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M86-E01007 GADDS User manual.book

1. Apparent 20 Size mm 4 1 40 20 40 60 80 100 120 140 160 1 19 25 0 09 0 26 0 54 1 04 1 41 1 62 1 63 1 44 1 08 0 59 2 9 63 0 03 0 11 0 25 0 51 0 70 0 81 0 82 0 73 0 55 0 31 5 3 85 0 03 0 09 0 19 0 27 0 32 0 33 0 30 0 23 0 14 10 1 93 0 03 0 08 0 13 0 16 0 17 0 16 0 13 0 08 20 0 98 0 03 0 05 0 07 0 08 0 08 0 07 0 05 30 0 67 0 01 0 03 0 04 0 05 0 06 0 05 0 04 40 0 52 0 02 0 03 0 04 0 04 0 04 0 04 50 0 44 0 01 0 02 0 03 0 04 0 04 0 04 90 0 34 0 01 0 01 0 02 0 03 Table 2 22 Beam divergence 20 spread in as a function of and 20 with a 0 5 mm collimator 6 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 40 20 40 60 80 100 120 140 160 1 32 08 0 14 0 43 0 89 1 73 2 35 2 69 2 71 2 40 1 80 0 98 2 16 04 0 05 0 19 0 42 0 84 1 16 1 34 1 36 1 21 0 92 0 51 57 6 42 0 05 0 14 0 32 0 45 0 53 0 55 0 50 0 39 0 23 10 3 22 0 05 0 14 0 21 0 26 0 28 0 26 0 21 0 14 20 1 64 0 05 0 09 0 12 0 14 0 14 0 12 0 09 30 1 12 0 02 0 05 0 07 0 09 0 10 0 09 0 07 40 0 87 0 03 0 05 0 06 0 07 0 07 0 06 50 0 73 0 01 0 03 0 05 0 06 0 06 0 06 9
2. M86 E01007 GADDS User Manual System Configuration 2 3 Goniometer and Stages The purpose of a goniometer and sample stages is to establish and control the geometric relationship between primary beam sample and detector All GADDS configurations are based on a D8 or PLATFORM for earlier ver sions goniometer The D8 goniometer is a high precision two circle goniometer with indepen dent stepper motors and optical encoders for 0 and 20 circles The selectable driving step size can be as small as 0 0001 The goniometer reproducibility is 0 0001 The D8 goniometer can be used in horizontal 0 20 vertical 0 20 and vertical 0 0 geometry Typical GADDS systems are built on the D8 goniometers in horizontal 0 20 geometry Figure 2 9 A vertical 0 0 configu ration is also available D8 Goniometr in theta 2theta horizontal configuration for GADDS systems top view eu Aca ha A i CATNTUFUR IRAIN S PEMA PODA B inner circle for omega stage Figure 2 9 D8 goniometer and two tracks for X ray tube and optics and detector stationary track for x ray tube and optics T slot for sample alignment system M86 E01007 System Configuration GADDS User Manual The central opening in the 0 ring provides the maximum possible flexibility for different sam ples and sample stages The offset track m
3. M86 E01007 GADDS User Manual Residual Stress 6 1 6 GADDS System Requirements The conventional method requires that the sam ple surface normally stay within the diffractome ter plane during data collection scanning A two position chi stage at y 0 5290 position or an XYZ stage or a cradle at y 0 yg 90 position can satisfy this requirement The new 2D stress method will work for any of the current sample stages fixed chi two position chi 1 4 circle cradle and XYZ stage The laser sample alignment system is highly recommended for residual stress measurement XYZ stage is nec essary for stress mapping function The 1 4 cir cle Eulerian Cradle or similar kind stages with all rotations c w 6 and translation X Y Z can dramatically increase GADDS stress tensor capability One example is to measure residual stress of a steel sample using the GADDS Microdiffraction system with Cr Ko radiation The configuration is shown in Figure 6 8 The XYZ stage can be replaced by a two position stage if stress tensor measurement is desired The detector position can be set to an appropriate value depending on the diffraction peak position For most ferrous alloys steels 211 peak at approximately 156 209 is used The detector is set at D 15 cm and highest swing angle 143 The w tilt is achieved by o rotation The relation between and vy tilt is given by 180 w 09 6 9 For example
4. gt GADDS General Area Detector Diffraction System V4 1 15 Copyr 1997 2003 Bruker ProJect File Edit Collect Process Analyze Peaks Special User Help SrMnO3 films Corundum 500snout 00 001 gfrm 02 13 04 08 57 39 Created 01 28 04 Mag Quad T 0 2 Theta 40 000 Width 0 0000 Counts 1290000 Time s 120 00 Distance 14 950 Size 1024 2th begi 23 300 2th en 56 000 chi begi 121 00 chi en 58 400 Distance 14 800 FloodFld 1024_015 Spatial 1024_015 1024x1024No HISTAR Figure 3 17 1D diffraction pattern M86 E01007 3 27 Basic System Operation GADDS User Manual 5 A pop up window will appear prompting you to save the integrated data Enter the file name title and set the file format to DIF FRACplus You can append add integra tion results from several frames into one DIFFRACplus file by checking the Append checkbox INTEGRATE Options x T e coumdum gt File name Corundum 500snouf es Format pFFRACpus H M Append Y N Scale factor ho Figure 3 18 Integrate options window 3 28 M86 E01007 GADDS User Manual Phase ID 4 Phase ID 4 1 Overview GADDS is a very powerful tool for analyzing the chemical composition of powder samples Because of its capability to collect the diffracted intensity from a large angular range the area detector has strong advantages compared to a conventional point detector system The large area of the GADDS detector allows for a large 20 range t
5. Step 5 spawn EVA and perform a search match operation n y i see your EVA manual on how to do this 6 Testthe script file by placing GADDS into command mode using Special Command Mode Then type PhaseID corund Corundum Test Sample Corundum 1 00 00 Within the script file PhaselD slm 1 is replaced by corund 2 is replaced by Corundum Test Sample 963 is replaced by Corundum and 964 is replaced by 1 00 00 M86 E01007 10 19 Script Files GADDS User Manual You can now process numerous samples using this script For example you could enter these commands at the command line prompt GADDS GPhaseID SampleXYZ Unknown geologic sample XYZ from stone quarry XYZ 2 00 00 GPhaseID A1234 Unknown whitish powder Sample A1234 A1234 5 00 00 10 20 M86 E01007 GADDS User Manual Script Files 10 5 Adding Script Files to the Menu Bar as User Tasks Scripts that are run frequently should be added to the menu bar as a user task which permits easy execution of the script file by a click of the mouse Up to 12 user tasks may be added to the menu bar by editing the GADDS SYS DATA usertask ini file and then restarting GADDS You can create user tasks used by all GADDS users or you can create different user tasks for different GADDS users Example You wish to add the PhaselD script created in the previous section to the menu bar so all your users can easily access the script The steps are
6. 6 4 2 Example 2 2D Method Comparison Between 2D Method and Conventional Method The residual stresses in the end surface of a carbon steel roller were measured by the con ventional method and the new 2D method The roller is a cylinder 1 long and 6 8 in diameter The stress data was taken from the center of the roller end The sample was loaded on the XYZ stage of the GADDS microdiffraction system A total of 7 frames were taken with w angles at 33 48 63 78 93 108 123 corresponding to y tilts of 69 54 39 24 9 6 and 21 for a nega tive detector swing angle with Cr Ka radiation Figure 6 25 shows the frame collected at 123 The 211 ring covers the x range from 60 to 120 In order to have sufficient back ground for each profile the x range of 67 5 to 112 5 was used for stress analysis First the frame data was integrated along the x angle in the interval of Ay 5 A total of 9 diffraction pro files were obtained from the x integration The diffraction profile at each y value is an integra tion in the range from x VeAy to y YeA y For example the profile at y 70 is the y integration from 67 5 to 72 5 The peak position 20 for each y angle was then obtained by fitting the profile with Pearson VII function A total of 63 data points in the form of 20 y can be obtained from the 7 frames M86 E01007 Residual Stress GADDS User Manual Figure 6 25 The diffraction data collected w
7. 2 Left click Process gt Spatial gt Unwarp to correct for spatial distortion Enter the num ber of frames in the second line and the full output file name in the third line Options for Process Spatial Unwarp Ea First input frame filename Sframe B it frames to process 1 First output frame filename Frame 1 gfrm E Suppress unwarping beam ctr Y7N Iv Check for yes Max display counts 7 cn Figure 3 14 Options for Process Spatial Unwarp window NOTE The output file name can be identical to the input file name Many users add a u to the original file name to mark it as unwarped Also if you want to unwarp a series of frames enter the full name including extension of the first data file in the first line 3 24 M86 E01007 GADDS User Manual Basic System Operation 3 8 Basic Data Analysis and 3 Select an integration area in one of the fol Preparation lowing ways For an initial analysis of the 2D data use the e _ If you know the integration range enter start special GADDS cursors from the Cursors menu and end values for 2 theta and chi in the See M86 Exx008 GADDS Reference Manual first four lines Press OK and hit Enter The for details integration result will appear e Press OK to exit the window A blue frame appears One at a time select numbers 1 4 and move the edges of the blue frame with To create and analyze a 1D diffraction pattern the arrow keys or by dragging the mouse to perform th
8. WIDTH 10 0 SCANTIME 4 TITLE 2 amp SAMPLE 3 NUMSAMPLE 0 NAME 1 RUN 0 FRAMENO 003 amp DISPLAY 16 REALTIME CLEAR MODE Scan SCAN SINGLERUN 1 2THETA 95 0 OMEGA 42 5 PHI 0 0 CHI 54 74 AXIS 2 amp WIDTH 10 0 SCANTIME 4 TITLE 2 amp SAMPLE 3 NUMSAMPLE 0 NAME 1 RUN 0 FRAMENO 004 amp DISPLAY 16 REALTIME CLEAR MODE Scan Step 3 integrate each frame into a raw range 10 18 M86 E01007 GADDS User Manual Script Files LOAD 1 0 001 DISPLAY 63 SCALE n OFFSET 0 0 INTEGRATE CHI 5 000 35 000 120 000 60 000 NORMAL 3 STEPSIZE 0 1 INTEGRATE WRITE TITLE FILENAME 1 FORMAT DIFFRACplus SCALE 1 0 LOAD 1 0 002 DISPLAY 63 SCALE n OFFSET 0 0 INTEGRATE CHI 30 000 60 000 115 000 75 000 NORMAL 3 STEPSIZE 0 1 INTEGRATE WRITE TITLE FILENAME 1 FORMAT DIFFRACplus APPEND amp SCALE 1 0 LOAD 1 0 003 DISPLAY 63 SCALE n OFFSET 0 0 INTEGRATE CHI 55 000 85 000 115 000 75 000 NORMAL 3 STEPSIZE 0 1 INTEGRATE WRITE TITLE FILENAME 1 FORMAT DIFFRACplus APPEND amp SCALE 1 0 LOAD 1 0 004 DISPLAY 63 SCALE n OFFSET 0 0 INTEGRATE CHI 80 000 110 000 115 000 75 000 NORMAL 3 STEPSIZE 0 1 INTEGRATE WRITE TITLE FILENAME 1 FORMAT DIFFRACplus APPEND amp SCALE 1 0 Step 4 merge multi range raw file into single range raw file SYSTEM GADDSSSYSTEM merge 1 raw 1 Merged raw
9. Blue rings will be overlaid on the frame s diffrac tion pattern The rings indicate the theoretical position of the calculated standard pattern 5 Adjust the sample to detector distance and x and y beam center settings so the rings of the calculated pattern coincide with those of the measured one To adjust the settings toggle between center mode changing x and y and calibrate mode changing the distance by pressing C and nudging the rings with the arrow keys until you get the results shown in Figure 3 11 5 1 Use the y parameter to get symmetry around the horizontal axis i e the deviations between the calculated and measured pattern are identical for the top and bottom of the detector 5 2 Use the x parameter to locally adjust the ring sections of measured and cal culated rings in the detector center 5 3 Use the distance parameter to get full coincidence M86 E01007 GADDS User Manual Basic System Operation GADDS General Area Detector Diffraction System V4 1 15 Copyr 1997 2003 Bruker ravect File EIE fect jeer Hele SrMn0O3 films Corundum 500snout_00_001 gfrm 02 10 04 16 44 38 Created 01 28 04 LEU elev 1 0 2 Theta 40 000 width 0 0000 Counts 1290000 Time s 120 00 Distance 14 950 Size 1024 Lambda 1 542 Distance 14 800 Angle 40 000 X center 514 00 Y center 514 83 2Th 70 000 x Ome 40 000 Y Phi 0 000 Zz Chi 90 000 Aux Shutter CLOSED Distance 14 850 FloodFld 1024 015 Sp
10. raw For the above example the filename is strs norm raw The next step is to calculate stress using DIF FRAC STRESS software DIFFRACP us STRESS can open the data saved in the last step For data format compatibility reasons the v tilt of GADDS data is saved as the y value for DIFFRACP S STRESS As such DIFFRACP us STRESS will process GADDS data as if it were collected in side inclination mode although the GADDS data was collected in iso inclination mode This will not change the stress result as long as the absorption and polarization correc tions are not performed in DIFFRACP us STRESS These corrections can be made in GADDS before data processing with DIFFRAC plus STRESS Verify that those correction func tions are disabled when analyzing GADDS data with DIFFRAC S STRESS Refer to the DIF FRAC 5 STRESS manual for details M86 E01007 Residual Stress GADDS User Manual 6 3 Stress Evaluation Using 2 Select Analyze gt Stress gt Biaxial 2D to acti Two Dimensional Data vate a parameter input menu for stress data 2D Method processing Figure 6 16 Input the following parameters For GADDS software version 4 0 or above the IST E new two dimensional approach is added to the es m Analyze menu All data processes and stress atheta start 15100 chietart 65 00 Step size 0 05 evaluations are performed within GADDS soft theta end 160 00 Chiend 115 00 GofS
11. ure 9 4 1 For accurate determination of the beam center and sample to detector distance cal ibrate the beam center and detector dis tance using a calibration standard and materials such as silver behenate Figure 9 4 At 30 cm you can observe five orders of silver behenate 00 reflections Stan dard files std for calibration are located in either the SAXS SYSDATA directory or the SAXI SYSDATA directory You can create additional calibration files with a text editor such as NOTEPAD Figure 9 4 Scattering pattern from silver behenate a low angle calibration material M86 E01007 9 9 Small Angle X ray Scattering GADDS User Manual 3 Readjust the beam stop to the center of the beam by checking the shadow of the beam stop with the conic cursor F9 The above calibration frame then redisplays with 4x magnification in Figure 9 5 The conic cur sor shows that the beam stop position is higher than the true beam center 4 In this case you should readjust the beam stop until the calibrated conic cursor is con centric with the shadow of the beam stop Figure 9 5 The center of the beam stop is above the center of conic circle 9 10 M86 E01007 GADDS User Manual Small Angle X ray Scattering 9 2 3 Data Collection A rat tail tendon sample is used as an example of data collection and to test the SAXS perfor mance The SAXS result measured with NanoSTAR a high end system dedicated to SAX
12. 0 01 0 01 0 01 0 01 0 01 40 0 52 0 01 0 01 0 01 0 01 0 01 50 0 44 0 01 0 01 0 01 0 01 90 0 34 0 01 0 01 M86 E01007 System Configuration GADDS User Manual Table 2 13 Beam divergence 20 spread in as a function of o and 20 with a 0 5 mm collimator 30 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 40 20 40 60 80 100 120 140 160 1 32 08 0 04 0 11 0 22 0 43 0 58 0 67 0 67 0 59 0 45 0 24 2 16 04 0 01 0 05 0 11 0 21 0 29 0 33 0 34 0 30 0 23 0 13 5 6 42 0 01 0 04 0 08 0 11 0 13 0 14 0 12 0 10 0 06 10 3 22 0 01 0 03 0 05 0 06 0 07 0 06 0 05 0 03 20 1 64 0 01 0 02 0 03 0 03 0 03 0 03 0 02 30 1 12 0 01 0 02 0 02 0 02 0 02 0 02 40 0 87 0 01 0 01 0 02 0 02 0 02 0 02 50 0 73 0 01 0 01 0 01 0 02 0 01 90 0 56 0 01 0 01 0 01 Table 2 14 Beam divergence 20 spread in as a function of o and 20 with a 0 05 mm collimator 15 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 1 40 20 40 60 80 100 120 140 160 1 3 21 0 01 0 0
13. GGCS Depress button A then press AXIS PRINT button The goniometer will drive to the first optical alignment position where the goni ometer head s X amp Z axes are perpendicular to the microscope s view direction if not your base angles are wrong View your sample through the microscope VIDEO program or LCD monitor depending on your system We will refer to these as microscope in the remainder of this proce dure For the moment assume that the micro Scope s crosshairs are properly aligned You can rotate the crosshairs physically on microscope software controlled on VIDEO can t on LCD for easier viewing Align crosshairs simple axis with phi axis and the division axis with tick marks perpendicular to phi axis Using goniometer head tool adjust Z verti cal and X left right until the sample is cen tered on the crosshairs While viewing the sample in the micro Scope use the manual control box Phoe nix Press ENTER GGCS Press AXIS PRINT Goniometer will drive phi by 180 The sample will move away from the crosshairs then return It should stop cen tered on the cross hairs yes jump to step 9 If not then your crosshairs are mis aligned which is extremely common 8 1 Using the goniometer head tool move the sample half way to the crosshairs use the tick marks Repeat this step adjusting the sample position until the start and end positions coincide If the Z crosshairs is misaligned
14. In this section we automate loading the library sample information entry and the start of data acquisition Automating the loading and unload ing of libraries involves robotics which is beyond the scope of this document We will use remote control of the GADDS program to send the new library information sample information and then start the data acquisition script The project information lines may store library infor mation The title information lines store individ ual well information The amount of information stored in frame headers is limited Raw headers are even more restrictive 11 6 M86 E01007 GADDS User Manual Automation 11 4 Remote Control Remote control of GADDS is performed by sending individual SLAM commands via win sockets from your master control program MCP Between GADDS and MCP resides the SMARTservice software layer on the frame buffer computer MCP talks to SMARTservice and SMARTservice talks to GADDS Unfortu nately the SMARTservice program is no longer supported by Bruker but it is supplied as is Install and run SMARTservice before starting GADDS SMARTservice can start GADDS online and GADDS off line but won t connect to the off line GADDS Only GADDS online will connect to SMARTservice Use the latest ver sion of GADDS Instrument status from SMART service is not yet implemented Our MCP generates several script files and sends them to the frame buffer computer To
15. M86 E01007 GADDS User Manual Residual Stress Considering the coefficient of Op as 1 2v E O11 012 O22 and Oph can be solved by least squares method When doing scan only 04 is equivalent to the conventional in iso inclina tion mode or when doing v or xg scan only O is equivalent to the conventional in side inclination mode NO O43 0 For biaxial stress with shear where Osa 20 and 23 we have Pii O11 Pio O12 P5 022 P13 013 P23 093 Poh Oph In sin Og sino 6 6 The biaxial stress state corresponds to the straight line of the d sin y plot And the biaxial stress with shear is the case when there is a split between the data points in y side and y side The general normal stress o and shear stress ty at any arbitrary given angle are given by Op 941 cos t 045 Sin20 c55Sin To 0130050 c53Sin 6 7 6 1 3 Relationship Between Conventional Theory and 2D Theory In order to find the relationship between the con ventional theory and the new 2D theory we first compare the configurations used for data collec tion in both cases The conventional diffraction profile is collected with a point detector scanning in the diffractometer plane or a position sensi tive detector mounted in the diffractometer plane The 2D diffraction data consists of dif fracted X ray intensity distribution on the detec tor plane The intensity distribution along any line defined by a fixed
16. MAG command see the SAXS Software Reference Manual 269 0204xx sec tion 5 1 4 With this command you can increase the number of pixels per degree using a selected area of the detector This is an elec tronic interpolation technique which produces smoother images For example the command FLOOD REPROCESS NORMAL PJ ZOOM FL XMIN 4096 YMIN 4096 MAG 2 will use a quarter of the detector about the beam center The number of pixels will remain 1024x1024 starting from the origin XMIN YMIN but each pixel is now 50 um instead of the usual 100 um The maximum recommended magnification is 4 M86 E01007 Small Angle X ray Scattering GADDS User Manual Adjusting the Beam Stop 1 Adjust the X and Y micrometers to visually position the beam stop in the center of the detector Position the glassy iron foil in the X ray beam path At low generator power open the shutter Alternatively the Fe99 source may be used Perform a 30 second ADD Display the frame with a maximum display count of 1 The position of the beam stop should be evi dent on the frame by the image of a dark cir cle A CAUTION Avoid exposing the detector to the direct beam To avoid detector damage never let the intensity exceed 200 CPS pixel Three situations can occur 1 No direct beam is observed In this case if a rotating anode generator is used open the shutter and allow the beam to warm the beam stop at the power level to be
17. Residual Stress 6 1 2 Theory and Algorithm of 2D Method The two dimensional approach has been devel oped to evaluate stress from 2D diffraction data The principle of the 2D method is to use all the data points on diffraction rings to calculate stresses getting better measurement results with less data collection time 3 5 The diffracted beams from a polycrystalline sample form a series of cones corresponding to each lattice plane as is shown in Figure 6 2 a The incident X ray beam lies along the rotation axis of the cones The apex angles of the cones are determined by the 20 values given by the Bragg equation The apex angels are twice the 20 values for forward reflection 20 90 and twice the values of 180 20 for backward reflec tion 20 gt 90 The y angle is the azimuthal angle from origin at the 6 o clock direction with rotation axis on the incident X ray beam in the opposite direction The y angle defines each diffracted beam on the diffraction cone The y angle here is not to be confused with the sample rotation y angle in 4 circle goniometer convention The dif fraction cones from an unstressed polycrystal line sample are regular cones in which 20 is independent of y and 20 209 Introducing a stress into the sample distorts the diffraction cone shape so that it is no longer a regular cone The 20 becomes a function of y 20 20 y this function is uniquely determined by the stress tensor and the sample orie
18. The measured stress with the conventional method and the new 2D method Conventional The new method with different numbers method of data points 3 points 5 points 7 points 9 points 776 62 MPa 769 38 775 33 777 26 769 23 850 m 1 ee PT s gool 800 fe 51 750 9 Q P ni 23 4 points ta 700 ge ue e m n 62 E 650 o 2 600 550 SUV 3pts 5pts 7pts 9pts METHODS a b Figure 6 26 Comparison of the conventional method and the new method with different numbers of data points a Data points taken from the diffraction ring total of 9 points from the diffraction ring in the x range of 67 5 to 112 5 with Ay 5 b Measured stress and standard deviation by different methods and from various numbers of data points M86 E01007 Residual Stress GADDS User Manual 6 4 3 Example 3 Stress Mapping with 2D Method Residual stress mappings on friction stir welded samples are measured on a GADDS with Huber 1 4 circle Eulerian cradle using the 2D method 6 The system with XYZ stage allows users to select the mapping area and steps The stress results are processed and mapped to the grid based on the user selected stress component The stress is measured on the aluminum 31 1 planes with Cr Ka radiation The X ray beam size is 0 8 mm in diameter Each diffraction frame is collected in 30 seconds and 5 frames per stress
19. a2 0 and a3 lt 0 The swing angle is sometimes called detector two theta in M86 E01007 Introduction and Overview GADDS User Manual GADDS documents and software We will use 20p to represent the detector swing angle here after in this manual It is very important to distin guish between the Bragg angle 20 and detector angle 20p 20 is the measured diffraction angle on the data frame At a given detector angle 20p a range of 20 values can be measured The 20 value corresponding to the center pixel is equal to 20p Users should be able to tell the dif ference between two parameters although the same symbol may be used for both variables in GADDS software or documents M86 E01007 GADDS User Manual Introduction and Overview 1 4 Diffraction Data Measured by an Area Detector Without any analysis an area detector frame can provide a quick overview of the crystallinity composition and orientation of a material If the observed Debye rings are smooth and continu ous the sample is polycrystalline and fine grained If the rings are continuous but spotty the material is polycrystalline and large grained Figure 1 11 Incomplete Debye rings indicate orientation or texture Figure 1 10 If only indi vidual spots are observed the material is single crystal which can be considered the extreme case of crystallographic texture Figure 1 9 Often you can visually determine the number of phases when the phases h
20. or A operator B A and B are strings which may include replaceable parameters and replaceable variables but not program variables Use single quotes around replaceables If both A and B are integers they are converted to integers before performing the operation Likewise if both are reals or one real one integer they are converted to reals The operator must be either or for equal lt gt or l for not equal gt for greater than or equal lt for less than or equal gt for greater than or lt for less than Multiple operators A B C are not allowed M86 E01007 10 27 Script Files GADDS User Manual Example similar to example in 10 6 For 3 different samples you collected an entire frame series with various numbers of frames and then noticed that the configuration settings were incorrectly set The wavelength distance and beam centers were erroneous You need to correct the frame headers for each frame in the frame series This task is ideally suited to using a 2 level nested script file and flow control The first script UpdateSamples slm would look like ON ERROR THEN CONTINUE UpdateFrames Corund_0 001 UpdateFrames Corund_1 001 UpdateFrames Corund 2 001 The second script UpdateFrames slm would look like Exit this script file on any error ON ERROR THEN STOP LET SF 1 Loop until Display Next gives error WHILE
21. tcollimates the beam divergency The exit beam divergency is controlled by the capil lary dimensions diameter and length and the critical angle of total reflection e tcan produce significant intensity gain on the sample relative to pinhole collimators M86 E01007 System Configuration GADDS User Manual Table 2 25 shows that 0 1 to 1 0 mm capillaries give practically the same spot sizes on the sam ple as the corresponding double pinhole colli mators The capillaries produce large intensity gain relative to the corresponding double pin hole collimators In the case of small beam size a special combination of capillary and pinhole may be favorable A capillary of large diameter captures more radiation near the source and transports it with less intensity loss The pinhole with smaller diameter defines the final beam size The combination can obtain more uni formly distributed radiation energy on the sam ple Table 2 25 Intensity gain calculated and experimental and beam spot size including 90 energy on sample for monocapillaries compared with double pinhole collimator Capillary Cu Ka radiation 8 0 keV Mo Ka radiation 17 4 keV Collimator Pinhole Gain Gain Spot Gain Gain Spot Spot 90 size d calc exp 90 calc exp 90 mm 0 10 110 66 0 18 39 40 0 14 0 10 0 30 15 10 0 34 5 6 5 9 0 31 0 31 0 50 7 4 6 0 0 50 2 6 3 0 0 49 0 50 1 00 3 4 4 2 0 89 1 2 1 5 0 97 0 98
22. then the rota tion center will be above or below the crosshairs Sometimes it is useful to coarsely adjust the Y position see steps 9 amp 10 9 Using the manual control box 9 1 Phoenix Press 2 then ENTER 9 2 GGCS Press B then AXIS PRINT Goniometer will drive phi by 90 M86 E01007 GADDS User Manual Basic System Operation 10 11 12 Using goniometer head tool adjust Y left right until sample is centered on the crosshairs or the true crosshairs center as determined in step 8 While viewing the sample in the microscope perform use the manual control box Phoe nix Press ENTER GGCS Press AXIS PRINT Goniometer will drive phi by 180 The sample should remain centered in the true crosshairs center Optional Use the other two optical positions Phoenix 3 amp 4 GGCS C amp D to double check your sample centering Axis Button Position 3 Circle Position 4 Circle 1 2 theta A o 2 omega B x Base Position 90 in Base Position 90 in 3 phi C 2 theta 180 in x 180 in o 4 chi D w 180inchi 90 180 in o 90 ino ino 13 Exit optical command by pressing ESC on the frame buffer s keyboard For reflection samples The procedure for mounting and aligning samples on the goniome ter head is assumes no laser attachment 1 Mount the sample to the goniometer head then attach assembly to the goniometer Sta
23. 0 23 0 30 0 246 0 101 0 42 0 80 0 060 0 060 0 33 0 50 0 266 0 148 0 64 0 80 0 060 0 060 0 53 0 80 0 327 0 148 0 97 0 80 0 060 0 060 0 83 The table also shows that the beam divergency decreases continuously with decreasing pinhole size for the combination of double pinhole colli mator and monochromator In some cases the application requires small beam size but not necessarily the small divergence We recom mend that you remove the pinhole 1 from the collimator tube to achieve higher beam intensity Table 2 8 gives the comparison between double pinhole collimators and single pinhole collima tors in terms of intensity gain the approximate ratio of single to double pinhole beam diver gency and beam spot size on sample 2 12 M86 E01007 GADDS User Manual System Configuration Table 2 8 Comparison between single pinhole collimator and double pinhole collimator in terms of intensity gain beam divergency angle p and beam spot size on sample D Collimator Intensity Single Double size gain pinhole pinhole d mm Single b x D mm b x D mm double 0 05 gt 20 0 174 0 14 0 041 0 07 0 10 16 0 184 0 20 0 082 0 14 0 20 4 0 205 0 31 0 164 0 29 0 30 2 4 0 225 0 42 0 225 0 42 0 50 1 2 0 266 0 64 0 266 0 64 0 80 1 0 0 327 0 97 0 327 0 97 The microdiffraction collimators are 50 um and 100 u
24. 1 Using NotePad open the file usertask ini which is located in the GADDS SYSDATA directory default is C saxi gadds32 2 Edit the file to add a new section for the PhaselD script See header of usertask ini for format 1 menu amp Phase ID help Collect integrate and merge data into 5 to 110 degree range slam D frames PhaseID parm 0 Basename Enter the basename jobname for all filenames parm 0 Title Enter sample title parm 0 Sample Enter sample name parm 0 Scan Time Enter scan time in seconds or as time string M86 E01007 10 21 Script Files GADDS User Manual 3 Save the file The final usertask ini file should look like User Task Initialization File for GADDS NT Format 84 Starts section for user task number 4 menu xxx menubar text inside quotes help xxx menubar help text inside quotes optional Slam xxx Slam command inside quotes without replaceable parms parm type xxx xxx parm type xxx xxx upto ten replaceable parameters with three values A P type is currently unused use 0 prompt text inside quotes R prompt help text inside quotes optional 1 menu amp Phase ID help Collect integrate and merge data into 5 to 110 degree range slam D frames PhaseID parm 0 Basename Enter the basename jobname for all filenames parm 0 Title Enter sample title parm 0 Sample Enter sample name parm 0 Sca
25. 1 X ray Powder Diffraction X ray diffraction XRD is a technique used to measure the atomic arrangement of materials When a monochromatic X ray beam hits a sam ple in addition to absorption and other phenom ena we observe X ray scattering with the same wavelength as the incident beam called coher ent X ray scattering The coherent scattering of X rays from a sample is not evenly distributed in space but is a function of the electron distribu tion in the sample The atomic arrangement in materials can be ordered like a single crystal or disordered like glass or liquid As such the intensity and spatial distributions of the scat tered X rays form a specific diffraction pattern which is the fingerprint of the sample There are many theories and equations about the relationship between the diffraction pattern and the material structure Bragg s law is a sim ple way to describe the diffraction of X rays by a crystal In Figure 1 1 the incident X rays hit the crystal planes in an angle 0 and the reflection angle is also 0 The diffraction pattern is a delta function when the Bragg condition is satisfied 2d sinO where A is the wavelength d is the distance between each adjacent crystal plane d spac ing and 0 is the Bragg angle at which one observes a diffraction peak 0 Figure 1 1 The incident X rays and reflected X rays make an angle of 0 symmetric to the normal of the crystal plane The diffraction
26. 2 7 Standard GADDS Systems 0 00 cette 2 37 2 8 Standard GADDS Systems for Combinatorial Screening 000 eee eae 2 45 2 8 1 Reflection Mode Screening 00 c cee eee 2 46 2 8 2 Transmission Mode Screening 000 c eee eee 2 48 2 8 3 Sample Stage and Screening Grid 0 0 0 cc eens 2 52 2 8 4 Retractable Knife Edge 0 eee 2 54 2 8 5 Diffraction Mapping and Results Display lisse 2 59 3 Basic System Operation 5 1x weariness WR ee DRE DURO dn 3 1 3 1 Starting the System ect Sacheakane epe b ek eee ed hed cO ud ihe ares 3 2 372 Selecting Optics ott tete p ves hela s ime emnes ied nsa 3 3 3 3 Choosing the Detector Position l iiiisiseee res 3 3 3 4 Detector Aberration Analysis lllseeeeeleee nn 3 5 3 4 1 Flood Field Correction ssssesseleeeee eae 3 8 3 4 2 Spatial Correction eode ur dames EN LEM UAE UNDO Ce DUE Ee E 3 10 3 5 System Calibration 2 setae bae AGH eae RR EARN wee ae ed C ea ae 3 14 3 6 Sample Positioning obese Leeks dee ceded uno Ed pcr deb ae been we 3 18 3 6 1 XYZ Stage Sample Positioning 0 000 e eee 3 18 3 6 2 Goniometer Head Sample Positioning 00 cece eee 3 19 3 6 3 Collision Limits for Your Sample 0000 cece tees 3 22 3 7 Data Collection zre tot ee foe Soba G4 be nia d a gems Were re belt abe x 3 23 3 7 Scan Method s ers ede dA eh a el wh Id bcd ee See ae he ate ds 3 23
27. 7 1 Size broadening calculated from the Scherrer equations for a given crystallite size t A and 20 value with C 0 9 anda 1 54184 A t A 20 5 10 15 20 30 40 50 60 70 80 20 3 98 3 99 4 01 4 04 4 12 4 23 4 39 4 59 4 85 5 19 30 2 65 2 66 2 67 2 69 2 74 2 82 2 92 3 06 3 24 3 46 40 1 99 2 00 2 00 2 02 2 06 2 12 2 19 2 30 2 43 2 59 50 1 59 1 60 1 60 1 61 1 65 1 69 1 75 1 84 1 94 2 08 100 0 80 0 80 0 80 0 81 0 82 0 85 0 88 0 92 0 97 1 04 200 0 40 0 40 0 40 0 40 0 41 0 42 0 44 0 46 0 49 0 52 300 0 27 0 27 0 27 0 27 0 27 0 28 0 29 0 31 0 32 0 35 400 0 20 0 20 0 20 0 20 0 21 0 21 0 22 0 23 0 24 0 26 500 0 16 0 16 0 16 0 16 0 16 0 17 0 18 0 18 0 19 0 21 1000 0 08 0 08 0 08 0 08 0 08 0 08 0 09 0 09 0 10 0 10 2000 0 04 0 04 0 04 0 04 0 04 0 04 0 04 0 05 0 05 0 05 4000 0 02 0 02 0 02 0 02 0 02 0 02 0 02 0 02 0 02 0 03 M86 E01007 GADDS User Manual Crystal Size 47 231 p Ww rrt eun2mmt2H 16 8 2 theta in degrees 33 5 Figure 7 2 u 111 peak from a semiconductor tab tape Profile fitting with a Cauchy function gives a peak location of 43 455 20 and a FWHM of 0 300 Using LaBg as an instrumental
28. 80 100 120 140 160 1 12 83 0 03 0 08 0 17 0 33 0 45 0 52 0 52 0 46 0 34 0 19 2 6 42 0 01 0 04 0 08 0 16 0 22 0 26 0 26 0 23 0 18 0 10 5 2 57 0 01 0 03 0 06 0 09 0 10 0 10 0 10 0 07 0 04 10 1 29 0 01 0 03 0 04 0 05 0 05 0 05 0 04 0 03 20 0 65 0 01 0 02 0 02 0 03 0 03 0 02 0 02 30 0 45 0 01 0 01 0 02 0 02 0 02 0 01 40 0 35 0 01 0 01 0 01 0 01 0 01 50 0 29 0 01 0 01 0 01 0 01 0 01 90 0 22 0 01 0 01 M86 E01007 System Configuration GADDS User Manual Table 2 17 Beam divergence 20 spread in as a function of o and 20 with a 0 3 mm collimator 15 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 40 20 40 60 80 100 120 140 160 1 19 25 0 04 0 12 0 26 0 50 0 68 0 78 0 79 0 69 0 52 0 28 2 9 63 0 01 0 05 0 12 0 24 0 33 0 39 0 39 0 35 0 26 0 15 5 3 85 0 01 0 04 0 09 0 13 0 15 0 16 0 14 0 11 0 07 10 1 93 0 01 0 04 0 06 0 07 0 08 0 07 0 06 0 04 20 0 98 0 01 0 03 0 03 0 04 0 04 0 03 0 03 30 0 67 0 01 0 02 0 03 0 03 0 03 0 02 40 0 52 0 01 0 01 0 02 0 02 0 02 0 02 50 0 4
29. E01007 Texture GADDS User Manual 5 30 M86 E01007 GADDS User Manual Residual Stress 6 Residual Stress The GADDS system has very strong residual stress measurement capability The two dimen sional 2D detector and laser sample alignment system give GADDS advantages over other instruments in dealing with highly textured mate rials large grain size small sample area weak diffraction stress mapping and biaxial stress tensor This feature along with phase analysis texture and other functions will make GADDS more desirable to users in semiconductor elec tronics and auto industries GADDS can measure residual stress strain using one of two approaches conventional or two dimensional These are discussed in detail in the following sections 6 1 Principle of Stress Measurement 6 1 1 Theory of Conventional Method In the conventional approach GADDS data on each frame is reduced by integration to a one dimensional diffraction profile so that the area detector measures stress in the same way as a linear position sensitive detector PSD This approach involves collecting data with GADDS and evaluating stress using DIFFRAC 4s STRESS software The fundamental equation used for conventional stress measurement is given as 1 2 xD 2 LESE m n2 2 Epy 44008 sin y ey Sin2osin y o5sin sin v 13C0s sin y Ea3SiNOSiN y 33C0S V 6 1 M86 E01007 Residual Stress GAD
30. Figure 9 10 Small angle scattering pattern of a polymer sheet cross section showing a hexagonal columnar structure Types of samples for small angle X ray scatter ing include Polymers fibers Wood products Detergents surfactants Lipids membranes Liquid crystals Catalysts ceramics Glasses M86 E01007 Small Angle X ray Scattering GADDS User Manual 9 4 References 1 O Glatter Small angle techniques International Tables for Crystallography Volume C edited by A J C Wilson pp 89 112 Kluwer Academic Publishers Dordrecht The Netherlands 1995 L E Alexander X Ray Diffraction Methods in Polymer Science Krieger Publishing Company Malabar Florida 1985 F J Balta Calleja and C G Vonk X ray Scatter ing of Synthetic Polymers Elsevier Science Pub lishing Company New York 1989 S Fakirov Z Denchev A A Apostolov M Stamm and C Fakirov Morphological charac terization during deformation of a poly ether ester thermoplastic elastomer by small angle X ray scattering Colloid Polym Sci 272 1363 1372 1994 P Fratzl and A Daxer Structural Transforma tion of Collagen Fibrils in Corneal Stoma During Drying An X ray Scattering Study Biophys J 64 1210 1214 1993 P Fratzl F Langmayr and O Paris Evaluation of 3D Small Angle Scattering from Non Spherical Particles in Single Crystals J Appl Cryst 26 820 826 1993 O Glatter and O Kratk
31. M86 E01007 System Configuration GADDS User Manual Table 2 9 Beam divergence 20 spread in as a function of and 20 with a 0 05 mm collimator 30 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 1 40 20 40 60 80 100 120 140 160 1 3 21 0 01 0 02 0 04 0 06 0 07 0 07 0 06 0 04 0 02 2 1 60 0 01 0 02 0 03 0 03 0 03 0 03 0 02 0 01 5 0 64 0 01 0 01 0 01 0 01 0 01 0 01 0 01 10 0 32 0 01 0 01 0 01 0 01 0 01 20 0 16 30 0 11 40 0 09 50 0 07 90 0 06 Table 2 10 Beam divergence 20 spread in as a function of o and 20 with a 0 1 mm collimator 30 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 7 40 20 40 60 80 100 120 140 160 1 6 42 0 01 0 02 0 04 0 09 0 12 0 13 0 13 0 12 0 09 0 05 2 3 21 0 01 0 02 0 04 0 06 0 07 0 07 0 06 0 05 0 03 5 1 28 0 01 0 02 0 02 0 03 0 03 0 02 0 02 0 01 10 0 64 0 01 0 01 0 01 0 01 0 01 0 01 0 01 20 0 33 0 01 0 01 0 01 0 01 30 0 22 40 0 17 50 0 15 90 0 11 M86 E01007 GADDS User Manual System Con
32. Q4y COS Q4 1 M86 E01007 Texture GADDS User Manual X N Y Figure 5 11 Relationship between the external physical coordinate system of the sample and an internal crystallographic reference frame In fibers uniaxial orientation is the most com monly observed symmetry If the z axis is taken as the fiber axis then cos o4 cos 4y Sub stitutions simplify the Pythagorean relation and lead to the Hermans orientation index fH 3 cos 9 1 which is an analytical representation of orienta tion of unit cells in a specimen based on the second moment of a specific unit cell axis e g the fiber axis with respect to a specific direction in the specimen e g the machine direction In films and sheets biaxial orientation is more common White and Spruiell modified the treat ment for uniaxial orientation to obtain biaxial ori entation indices fB 2 cos o1 cos pry 1 fB 2 cos o cos o 1 Regardless of whether uniaxial or biaxial orien tation is present the orientation factors are usu ally displayed as diagrams which show the relationship between the crystallite orientation and the orientation of the sample For the simul taneous calculation of Hermans and White Spruiell indices the pole figure can be submit ted to POLE FIGURE ORIENT A graphical representation of the orientation indices known as a Stein triangle is obtained using POLE FIGURE STEIN This met
33. SAMPLE Corundum NUMSAMPLE 0 NAME corund RUN 0 FRAMENO 001 amp DISPLAY 16 REALTIME CLEAR MODE Scan SCAN SINGLERUN 1 2THETA 45 0 OMEGA 17 5 0 PHI 0 0 CHI 54 74 AXIS 2 amp WIDTH 10 0 SCANTIME 1 00 00 TITLE Corundum Test Sample amp SAMPLE Corundum NUMSAMPLE 0 NAME corund RUN 0 FRAMENO 002 amp DISPLAY 16 REALTIME CLEAR MODE Scan SCAN SINGLERUN 1 2THETA 70 0 OMEGA 30 0 PHI 0 0 CHI 54 74 AXIS 2 amp WIDTH 10 0 SCANTIME 1 00 00 TITLE Corundum Test Sample amp SAMPLE Corundum NUMSAMPLE 0 NAME corund RUN 0 FRAMENO 003 amp DISPLAY 16 REALTI CLEAR MODE Scan SCAN SINGLERUN 1 2THETA 95 0 OMEGA 42 5 PHI 0 0 CHI 54 74 AXIS 2 amp WIDTH 10 0 SCANTIME 1 00 00 TITLE Corundum Test Sample amp SAMPLE Corundum NUMSAMPLE 0 NAME corund RUN 0 FRAMENO 004 amp DISPLAY 16 REALTIME CLEAR MODE Scan GI Step 3 integrate each frame into a raw range LOAD corund0 001 DISPLAY 63 SCALE n OFFSET 0 0 INTEGRATE CHI 5 000 35 000 120 000 60 000 NORMAL 3 STEPSIZE 0 1 INTEGRATE WRITE STITLE FILENAME corund FORMAT DIFFRACplus SCALE 1 0 LOAD corund0 002 DISPLAY 63 SCALE n OFFSET 0 0 10 14 M86 E01007 GADDS User Manual Script Files GRATE CHI 30 000 60 000 115 000 75 000 NORMAL 3 STEPSIZE 0 1 GRAT WRITE TITLE FILENAME corund FORMAT DIFFRACplus APPEND amp SCALE 1 0 LOAD corund0 003 DISPLAY 63 SCALE n OFFSET 0 0 1 RATE CH
34. The choice of sample to detector distance for a texture experiment depends on the resolution required to separate adjacent diffraction lines and the need to collect multiple poles simulta neously For most metals and polymers the dis tance is 6 cm To sample a larger number of crystallites an oscillator can be attached to the two position x stage or 4 cradle A maximum of 12 mm of stroke is attainable Two types of oscillators exist 1 rotation below translation Rot Trans and 2 translation below rotation Trans Rot The Rot Trans design can be used with the 14 cradle Trans Rot samples different grains as a function of rotation Rot Trans samples the same grains as a function of rotation The following are other general considerations for texture measurements e For disk space considerations the recom mended frame size for complete pole fig ures is 512x512 For fiber texture plots 1024x1024 frames can be used e For pole figure data collection a 0 5 mm collimator is recommended Smaller colli mators are only necessary when collecting selected area microtexture data e The recommended sample to detector dis tance for texture measurements is 6 cm Larger distances are only necessary to resolve closely spaced lines For reflection measurements adjust the machine direction MD of the sample to be vertical when x 90 then use GONIOME TER UPDATE to set 0 before starting pole figure data collection If t
35. User Manual S XS Figure 2 20 Standard Centric Eulerian 4 Cradle System 2 42 M86 E01007 GADDS User Manual System Configuration The specifications and application features of the five standard systems are listed in Tables 2 30 and 2 31 A custom system can be built by modifying one of the five standard systems Table 2 30 Specifications and major components of the five standard GADDS systems in horizontal configuration Specifications Basic Fixed Chi Microdiffraction Stress Texture Eulerian 1 4 Cradle Large or Small Major Components same for all five Horizontal D8 0 20 goniometer and microprocessor control unit D8 radiation safety enclosure Base cabinet Kristalloflex 760 X ray generator Outer circle track for detector Stationary track for X ray tube and optics SDOF tube mount HI STAR area detector system and frame buffer computer Graphite monochromator and pinhole collimator support GADDS software Major Components Fixed chi stage and goniometer head opti cal microscope 0 5 mm pinhole collimator XYZ stage Laser video sample alignment sys tem 0 05 0 1 0 3 and 0 5 mm pinhole collima tors Two position chi stage Laser video sample alignment system 0 5 and 0 8 mm pinhole collimators Huber or Centric Eule rian 1 4 cradle Laser video sample align ment system 0 05 0 1 0 3 0 5 and 0 8 mm pinhole collima tors X ray Tar
36. X rays about the takeoff angle The monochroma M86 E01007 System Configuration GADDS User Manual tor can be used for takeoff angles from 3 to 6 typically set to 6 The graphite crystal cannot resolve K 4 and Kj lines so it is aligned to the K line The monochromator is designed to use various anode materials Their 20 angles are listed in Table 2 6 You may need to input the 20m value if you choose to process data with polarization correction See the service manual 269 005502 for PA monochromator for mono chromator alignment Table 2 6 Bragg angles of graphite crystal 002 plane for various target materials Target Materials Ka Wavelength Bragg angle 20M Ag 0 560868 9 58 Mo 0 710730 12 14 Cu 1 541838 26 53 Co 1 790260 30 90 Fe 1 937355 33 51 Cr 2 29100 39 87 2 2 2 Pinhole Collimator The pinhole collimator is normally used to con trol the beam size and divergence In GADDS Systems the pinhole collimator is normally used with a monochromator or a set of cross coupled G bel mirrors Figure 2 6 shows the X ray beam path in a pinhole collimator achieved with two pinholes apertures of the same diameter d sep arated by a distance h F is the dimension of the projection of focal spot or beam focus projection from the monochromator or G bel mirrors The distance between the focus and the second pin hole is H The distance from the second pinhole to the sample
37. and adding it to the menu bar BRUKER ANALYTICAL X RAY SYSTEMS Micro diffraction Laser video alignment micro wire 20 micron wire is positioned with the laser video microscope XRD Phase ID application proves it is Copper As ml BRUKER ANALYTICAL X RAY SYSTEMS Micro diffraction Laser video alignment car paint Lackgplitter ajs jz BRUKER ANALYTICAL X RAY SYSTEMS Micro diffraction Laser video alignment c Figure 4 8 Typical applications for forensic work M86 E01007 Phase ID GADDS User Manual 4 10 M86 E01007 GADDS User Manual Texture 5 Texture 5 1 Overview A major part of condensed matter like minerals rocks soils ice but also artificially synthesized phases like metals ceramics etc are found to be polycrystalline Bunge Classic examples of materials that have been examined by texture analysis are geologic samples rolled metal sheets and polymer fibers New materials that are examined include thin film layers on silicon and superconductor thin films The sample mor phology is defined by properties like position crystallite size grain boundaries shape and orientation of the individual crystallites Crystal lographic texture also known as crystallite ori entation distribution is an important property of materials The meaning of orientation becomes obvious when looking at macroscopic properties that are anisotropic for single crys tals Misarranged
38. and external methods This correction is unnecessary if the same material is examined and its density var ies no more than 20 The Compton scattering table used by GADDS is SAXI GADDS32 COMPTON TBL which you can view using a text editor such as NOTEPAD Examples of the empirical formula syntax follow e AL 3 20 3 for aluminum oxide AloOs If O 2 were instead used a warning would be issued that no such entry exists in the scat tering table C12H2202N 2 for Nylon 66 For poly mers input the repeat unit Note that the default values in the table for C and O are not for covalently bonded systems Two new entries should be made in this table see Table 3 4 4 2B in the International Tables Vol III 1968 sind A 0 0 0 1 0 2 0 3 0 4 0 5 06 07 0 8 1 1 Cv 0 000 1 203 2 914 3 826 4 238 4 486 4 686 4 871 5 044 5 462 OV 0 000 0 966 2 777 4 275 5 243 5 818 6 170 6 408 6 593 7 025 8 4 M86 E01007 GADDS User Manual Percent Crystallinity To correct for Compton scattering 1 Compute the scattering function using PERCENT_CRYSTAL COMPTON 2 Specify the COMPTON qualifier with PERCENT_CRYSTAL INTERNAL or PERCENT_CRYSTAL EXTERNAL Pres ently PERCENT_CRYSTAL FULL does not allow for the Compton correction Internal Method PERCENT_CRYSTAL INTERNAL Figure 8 3 y Nylon powder You ll want to use the internal method when you se
39. and residual stress from precise locations on irregularly shaped parts including curved surfaces beamstop doa d am monochromator E e collimator X ray tube 9 c e instrument center fixed chi stage Figure 2 4 Typical X ray optics in standard GADDS includes X ray tube monochromator collimator and beam stop Also shown are the instrument center and the shadow of a fixed chi stage M86 E01007 GADDS User Manual System Configuration 2 2 1 Monochromator An important consideration for your system is that you will want to have an appropriate mono chromator for the characteristics of the source specimen and instrument geometry A crystal monochromator is typically used with a sealed tube or rotating anode generator to allow only a selected characteristic line K or K 4 to pass through the optics While X rays generated from a sealed X ray tube or rotating anode generator consist of white radiation and other characteris tic radiation lines most X ray diffraction applica tions need only the K or K line They need only this line because the white radiation pro duces an unwanted high background in the dif fraction pattern and the other characteristic lines produce extra and unwanted diffraction peaks rings in the diffraction pattern A crystal monochromator is illustrated in Figure 2 5 The single crystal has a d spacing d The wavelength of the X rays
40. area detector image frame is stored as intensity values on a 1024x1024 pixel grid The 20 and y values on each pixel are also given by GADDS The diffraction profile on a particular y line can be calculated from the 2D image by a y integration within a given x range The peak position at each y angle can be deter mined from the diffraction profile by one of the many available peak fitting methods The num ber of data points from one ring depends on the total y range and y integration steps The diffrac tion cone distortion due to stresses is recorded as a function 20 y All the information about the sample orientation diffraction cone orientation and diffraction cone distortion leads to the reso lution of the stress or strain S2 N Figure 6 3 The diffraction rings collected on area detectors at on axis or off axis positions M86 E01007 Incident beam GADDS User Manual Residual Stress In the sample coordinate system S4S585 the strain tensor is 11 12 13 21 22 23 31 32 amp where 42 21 13 31 and 23 32 The strain tensor in the sample coordinates the sample orientation y gt and the diffraction data y 20 are related by the following expres sion fiij fi5 15 f5 25 fi3813 3255 3633 in Sing sino 6 2 where strain coefficients f can be calculated from simplified equations listed in Table 6 1 In sin0g sin0 determines the d
41. center Figure 2 12b The 3D view of the laser video sample alignment system is illustrated in Figure 2 12c 5 4 eee m ac video right sample position t laser spot at cross hair of video image sample represents the measured spot on sample a c Figure 2 12 Laser video sample alignment system with a principle of laser video alignment system b image of laser spot and crosshair and c illustration of the laser video system M86 E01007 GADDS User Manual System Configuration The specifications and applications of the three sample alignment systems are listed in Table 2 27 Table 2 27 Specifications and Applications of Three Sample Alignment Systems 45 171x 1 36CCD 136 display Primary zoom magnification 0 75 3x Working distance 61 mm Field of view 8 2 mm Color video camera NTSC Picture element 768H x 494V Horizontal resolution gt 480 TV lines Frame grabber and image software User selectable video reticles System Specification Application Optical Magnification 40x Sample alignment suitable for capillary single crystal and Microscope Working distance 73 mm small samples System alignment Field of view 6 1 mm Reticle crosshair 20mm division Video Magnification Sample alignment suitable for capillary single crystal and Microscope 30 114x 1 26 CCD 136 display small samples Monitor the sample durin
42. click Process Flood Linear to dis field after FloodFld in the main window is able any existing flood field correction The set to linear main window will appear see Figure 3 4 Begin the flood field correction O GADDS General Area Detector Diffraction System V4 1 15 Copyr 1997 2003 Bruker ProJect File Edit Collect Process Analyze Peaks Special User Help SrMn0O3 films Irreg PF lowv 01 001 gfrm 02 09 04 15 25 49 Created 02 09 04 L 0 0 0000 3 000 37932 40 007 Distance 14 850 Size 1024 2Th 35 000 Ome 12 000 Phi 0 000 Chi 90 000 Aux Shutter CLOSED Distance 14 850 FloodFld LINEAR Spatial LINEAR 024x1024 Cu Bias Figure 3 4 Main window 3 8 M86 E01007 GADDS User Manual Basic System Operation 2 Left click Process gt Flood gt New The FLOOD NEW Options window appears see see Figure 3 5 FLOOD NEW Options 1024x1024 frames x Max seconds 30 00 Max counts fi 0000000 Max display counts n iv Realtime display Y N Output filename 1024 015 fl E Lower X 0 Lower Y 0 Magnification fi iv Open amp close shutter Y N Cancel Figure 3 5 FLOOD NEW Options window NOTE The GADDS software will suggest a default output filename in line 5 Do not change the filename The first four digits describe the detector resolution as set in the configuration table accessed with Edit Configure Edit For the HI STAR the digits can be either 1024
43. crystallites can cause exces sive earing in deep draw sheets breakage in fibers poor bonding in composites and high rejection rates for semiconductors As more materials are formulated at a molecular level texture must be specified and controlled to ensure proper product performance Texture analysis is the key to understanding material properties like e Mechanical strength and elasticity e Electrical resistance and capacitance e Thermal conductivity e Magnetic and optical properties e Scattering of electromagnetic or mechanical waves An example for a specimen with only one orien tation is a single crystal Ideal polycrystalline material has diffracting domains or crystallites that are randomly distributed Texture is described with respect to a sample coordinate system M86 E01007 Texture GADDS User Manual X ray diffraction allows the direct measurement of the hkl axes distribution by looking at a fixed 20 range while varying the sample orienta tion in the diffractometer The intensity distribu tion could be visualized as intensity mountains on the pole sphere where each unit of the pole sphere represents the diffracted intensity at a sample orientation The 3D pole sphere is typically reduced to a 2D pole figure by stereographic projection which is the primary representation used to describe crystallite orientation see Figure 5 1 amp Cullity 1978 These projections are relative to sample
44. data point at various vy and angles Two specimens were made by friction stir weld ing with rotation speed of 580 rpm and welding speed of 113 mm min and 195 mm min respec tively The specimens will be denoted as 113 and 195 thereafter The stress mapping takes 1 mm stepwise scan for 0 40 mm from the center line and 5 mm stepwise scan from 40 mm to the edges The specimen is loaded on the XYZ stage of the Eulerian cradle Figure 6 27 and each mapping spot is aligned to the instrument center with the laser video alignment system Figure 6 27 Specimen loaded on the XYZ stage of the Eulerian cradle and the mapping spot is aligned with the laser video system M86 E01007 GADDS User Manual Residual Stress The residual stress mapping results on the top surface with 40 mm from the center line are shown in Figure 6 28 The stresses in the longi tudinal direction 025 form a double peak profile symmetric to the weld center line A similar pro file was observed with neutron diffraction The relative small X ray beam size may be the cause of severe scattering data Longitudinal Normal Stress 150 100 50 113 o 195 113 195 Residual Stress MPa o 100 150 40 30 20 10 0 10 20 30 40 Distance from Weld Center Line mm Figure 6 28 Residual stresses in longitudinal direction O22 on the top surface within 40 mm from the weld center line M86 E01007 Resi
45. distribu tion along the Debye rings is inhomogeneous Consequently the scans strongly differ as a function of the scanning direction Figure 4 3 Schematic intensity versus 20 The intensity versus 20 plot shows the y integra tion result of the two dimensional intensity distri bution collected with an area detector The plot clearly shows all lines of the sample This is not true for the schematic point detector scans in Figure 4 1 After integration use DIFFRAC S Evaluation Search Match software and import the inte grated spectra This package allows you to use the ICDD PDF database formerly JCPDS for final phase identification See the DIFFRACP s EVA manual and Figure 4 4 M86 E01007 GADDS User Manual Phase ID R EVA phaselD EVA eee VM MM rc Li Be Na Mai K Ca Sc Ti V Cr Mn Fe Col Ni Cul Zn Gal Ge As Sel Br Kr Rb Sr Y Zr Nb Mo Te Rul Rh Pa Ag Cal In Sn Sh Te 1 Xe Cs Ba La Hf Ta W Re Os ir Pt Aul Hg TI Pk Bi Po At Rn Fr Ral Aci Cel Pr Nd Pm Sin Eu Gal Th Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am cml Bk Cf Es Fm Mal Nol Figure 4 4 Database search for unknown phases M86 E01007 4 5 Phase ID GADDS User Manual 4 2 Performing a phase ID analysis The following procedure contains the necessary steps to perform a phase ID analysis 1 Choose a wavelength that does not cause fluorescence i
46. estimated or pre determined 209 do use 156 for most steels This value is also used as initial peak 20 value in profile fitting so 204 lt 209 lt 205 Title Title to use the frame title or input other title File name The processed raw data will be saved in this filename HKL The diffraction plane index Young s modulus Poisson s ratio and anisotro pic factor Agx can be found in previous sections or literature Lineshape select one of the four peak fitting functions 3 Click OK to display the selected data region You can redefine 204 205 1 x by using the mouse or keyboard see Figure 6 17 GADDS General Area Detector Diffraction System V4 A 02 Copyr 1997 98 Bruker Project Efe Edt Colect Process Anaie Peske Special User Help o Time s 006 Distance 14 900 Size 1024 2th begi 153 00 2th en 160 00 chi begi 65 000 chi en 115 00 Distance 12 000 FloodFld LINEAR Spatial LINEAR 1024x1024 No PDC 1 2 3 4 Select edge M Move ENTER L button Integrate ESC O buttons Quit Figure 6 17 Selected data region on frame 201 205 x1 x2 define the selected diffraction ring 204 and 205 determine the background of the profiles y4 and xo determine the angular range of the diffraction ring The y integration range Ax of each profile is determined by Ax xa7x1 n It is very important to keep the parameters and settings consistent through all the measure ment
47. exposed to the X ray beam will be x and y away from the original spot In the past GADDS documents and software have used the symbol y or chi for both diffrac tion cone and sample orientation In this man ual we will adopt the two new symbols y gamma represents the direction of diffracted beam on the diffraction cone and v psi repre sents a sample rotation angle Users may see either the old or new symbol definition depend ing on the version of hardware or software but can normally distinguish the two parameters from the definition if they are aware of the differ ence 1 3 4 Detector Position in the Laboratory System As previously mentioned the detector position is defined by the sample to detector distance D and the detector swing angle a In the laboratory coordinates X Y Z detectors at different posi tions are shown in Figure 1 8 Figure 1 8 Detector position in the laboratory system X YLZ D is the sample to detector distance a is the swing angle of the detector Three planes 1 3 represent the detection planes of three 2D detectors The detector dis tance D is defined as the perpendicular distance from the goniometer center to the detection plane The swing angle a is a right handed rota tion angle above Z axis Detector 1 is exactly centered on the positive side of X axis and its swing angle is zero on axis Detectors 2 and 3 are rotated away from X axis with negative swing angles
48. figure a This must be edited to indicate the edge of the pole figure data The permutation parame ter IPER must also be set according to whether the GADDS pole figure data was collected in transmission or reflection In the transmission cases described in Figure 5 6 the IPER param eter has the value 312 In the reflection case described in Figure 5 6 the IPER parameter has the value 213 No additional processing is required for GADDS data exported with POLE FIGURE TEX TUREAT for use with ODF AT 5 14 Hermans and White Spruiell Orientation Indices Figure 5 11 shows the relationship between the external physical coordinate system of the sample and an internal crystallographic refer ence frame The angles between the axes 1 2 and 3 of the individual molecular units and the main sample directions x y and z are denoted 91x 02x 03x Pry Pay P3y ANd 12 927 937 In amorphous polymers there are no true crystal lites and one observes rotation around each of the molecular axes In polymers discrete crys tallites can be observed in which a crystallo graphic axis coincides with at least one of the molecular axes In addition this crystallographic axis is usually aligned with a physical axis As in other materials the crystal symmetry can range from cubic to triclinic and the standard rules concerning the position of rotation axes apply In any case the following Pythagorean relation must hold true COS Qi COS
49. for most steel with bcc bct crystal structure 209 156 the neutral o position is 102 If you want to set a stress data collection from y 45 to 45 with 15 steps you would have to set o step scan from 57 to 147 with 15 steps User Figure 6 8 The stress measurement configuration of GADDS Microdiffraction System M86 E01007 Residual Stress GADDS User Manual 6 1 7 Data Collection Strategy X ray diffraction measures stress by measuring the d spacing change caused by the stress The diffraction vector is in the normal direction of the measured crystalline planes It is not always possible to have the diffraction vector on the desired measurement direction In the reflection mode X ray diffraction it is easy to have the dif fraction vector normal to the sample surface but impossible to have the vector on the surface plane The stress on the surface plane or biax ial stress is calculated by elasticity theory The final stress result can be considered as an extrapolation from the measured values So that in the conventional sin y method several y tilt angles are required typically from 45 to 45 The same is true with an XRD system The diffraction vectors corresponding to the data scan can be projected in a 2D plot in the Options for Analyze Stress Scheme 2D x bep ooo S Bis jj Stress Peak fi 56 0 deg fil same way as the pole density distribution in a pole figure Th
50. frame corund0 001 e Use Peaks gt Integrate gt Chi to integrate from 5 to 35 degrees 120 to 60 in chi Save as file corund and no append e Use File gt Load to load the second frame corund0 002 e Use Peaks gt Integrate gt Chi to integrate from 30 to 60 degrees 110 to 70 in chi 10 Use Peaks gt Integrate gt Chi to integrate from 55 to 85 degrees 105 to 75 in chi Save as file corund and yes to append Use File gt Load to load the fourth frame corund0 004 Use Peaks gt Integrate gt Chi to integrate from 80 to 110 degrees 105 to 75 in chi Save as file corund and yes to append Merge the multi range raw file into a single range Use the Special gt System command to spawn the merge command Use the File gt Script Enabled command to toggle status which will stop the auto script ing feature Then close the GADDS pro gram Now we will edit the auto created script file using NotePad We need to add comments and to correct any mistakes and omissions 11 Start NotePad and load the PhaselD slm file Save gs Tile Carna and yes to eppend from the project s working directory Make e Use File gt Load to load the third frame sure word wrap is off corund0 003 Command GADDSSSYSTEM merge Figure 10 4 Options for Special System 10 10 M86 E01007 GADDS User Manual Script Files 12 Print the script file so you have a reference to refer to The fi
51. handed rotation angle about the laboratory axis Z When the center of the detector plane is right on the axis X the detector angle is zero In the manual and software this angle is denoted by a 20p or 2 theta Detector Distance The distance between the detection plane and the instrument center D also called sample to detector distance or crystal to detector distance Detector Plane The reference plane that the 2D diffraction pattern is measured A 2D detector is con sidered as such a plane in the diffraction geometry Detector Position Detector position consists of detector to sample distance D and detector swing angle a or 2 theta M86 E01007 GADDS User Manual Nomenclature and Glossary Diffraction X ray Constructive interference of X ray beams that are scattered by atoms of crystals Diffraction Cone The diffracted beams from a powder poly crystalline sample form a series of cones corresponding to each lattice index The rotation axis of the cone lies on the incident X ray beam Each cone shape is deter mined by the Bragg angle 20 and the azi muthal angle x Diffraction Pattern The experimentally measured values of intensities diffraction angles direction and order of diffraction for each diffracted beam obtained when a sample is place in a nar row beam of X rays or neutrons Diffraction Rings The conic section of the detector plane on the diffraction cones Also c
52. hardware limit switches from the manufacturing set tings for a particular application mark the original positions make a note and recover the limit switch immediately after finishing the application e Check all software limit settings immediately after starting the instrument and software or after changing components or a sample of different size and shape Manually drive each axis for the range to be used in data collection before starting an automatic data scan especially for a new sample or goniometer position Update the software limit settings based on data collection strategy and sample size Find a safe path from one goniometer position to another position driving all axes to the new positions randomly or simulta neously may cause a collision The safe path can typically be found by manually driving all axes from the existing position to the new position Add safe path positions in a slm file for automatic data collection Before starting an unattended long term data collection session take a test run first with the same data collection strategy but short collection time and coarse steps Before homing an axis drive other axes to clear space for the home position Then drive that axis to the vicinity of the home position Remember all of the emergency software or hardware measures to stop a run in case of danger of collision M86 E01007 GADDS User Manual Basic System Opera
53. if a set of 7 data frames strsnom 000 006 is used for stress evaluation open the first frame strsnorm 000 Figure 6 12 Input an appropriate High counts value so the dif fraction ring and background region are visi ble x Frame filename DABruker backuptStressistrsnorm 0O y El Window Level Quadrant foru zf Low counts fo a High counts Region le fee Y jee Magnification Poo Autoincrement I Preserve Graphics I Use orientation in header Add HKL Overlay Figure 6 12 Open file menu of GADDS F Display associated video image 2 Select Analyze Stress Conventional to activate the parameter menu for stress data processing Figure 6 13 and input the parameters shown x 2theta chi start fis2 00 deg start p 00 deg end 81 00 deg end 95 00 deg Normalize intensity 5 Bin normalized gt Step size jor Peak 2T fis60 deg Title STITLE sss File name stress raw j Figure 6 13 Parameter input menu for Conventional Stress Analysis 2theta start lower 20 of conic region 204 2theta end upper 20 of conic region 209 Chi start lower y of conic region 1 90 AX Chi end upper x y of conic region xy 90 AX Normalize intensity 3 for solid angle Step size 20 step size in the integrated profile data default 0 1 choose smaller value for sharper peak Peak 2T Input the estimated or pre deter
54. image 1D profile O D point Field of view 11 5 cm 10 15 cm point diameter area linear Pixel format 1024x1024 1x 1000 1 512x512 2000 Pixel size 105 um 210 mm 100 um N A Point spread 200 um function Quantum 80 80 70 90 efficiency 8 keV Sensitivity 1 photon pixel 1 photon pixel Figure 2 13 HI STAR Area Detector Dynamic range 5406 gt 10 107 The area detector has a large imaging area Overall count 10 x 10 s 5x104 s 105s 11 5 cm diameter for X ray detection It is sen rate sitive to X ray wavelengths corresponding to the Local count rate 200 cps pixel with N A 3 15keV energy range and is a true photon pixel 512x512 frame counting device with an absolute detection effi Noise rate 10 pixel s 2 10 s ciency of 80 percent It can collect a data frame Energy range 3 15 keV 5 50 keV of 1024x1024 or 512x512 pixels with the pixel Eneravr eolu Tez 189i ree size of 105 um 210 um for 512x512 frames tion AE E For most X ray diffraction applications the HI STAR system can be 104 times faster than a scintillation counter and 100 times faster than a linear position sensitive detector PSD Table 2 34 M86 E01007 GADDS User Manual System Configuration The HI STAR consists of an X ray proportional chamber with a precision two dimensional mul tiwire grid an integral pre amplifier high resolu tion high speed decoding electronics and a frame buffer computer for data collection stor age and detec
55. inverse transformation from the scattering intensity p n 23 l q qrsin qr dq 9 4 9 4 The equation gives the direct relationship between the measured scattering intensity I q and the PDDF p r More basic equations for the SAXS can found in a number of textbooks and literature listed at the end of this section M86 E01007 GADDS User Manual Small Angle X ray Scattering 9 1 2 X ray Beam Collimation The collimation system defines the size shape and divergency of the X ray beam The collima tion also determines the resolution of a SAXS system When GADDS is used for SAXS either the supplied pinhole collimators or custom made collimators are used for the system depending on the required achievable resolution Figure 9 1 shows the collimation of the SAXS system with pinhole collimator sample beam stop and detector The primary beam consisting of paral lel and divergent components is blocked by the beam stop The maximum angular resolution Omax iS given as Qmax Q4 t o 9 5 where o4 is the maximum angular divergence of the incident beam which is given in Table 2 7 of section 2 denoted as p And a2 is the maximum angular deviation of the X rays recorded in the detector defined by the beam spot on the sam ple D and the resolution element of the detec tor d D is listed in the same table as above and the spatial resolution d 20 2 mm for HI STAR detector D d 9 6 T 9 6 Oo T
56. line focus beam and point focus beam The size and shape of the focal spot is one of the most important features for an X ray genera tor Sealed X ray tubes normally have 2 to 4 beryllium windows through which X rays may exit The focal spot is typically rectangular with a M86 E01007 GADDS User Manual System Configuration length to width ratio of 10 to 1 The projection along the length of the focal spot at a takeoff angle from the anode surface is called spot focus or square focus or point focus The pro jection of the focal spot perpendicular to its length is called line focus Thus line focus and spot focus are separated by an angle of 90 around the tube cylinder The line focus is com monly used for the conventional diffractometer with point detector or PSD A standard GADDS system uses the spot focus The takeoff angle can be set from 3 to 7 6 for most systems Table 2 3 lists focal spot size line focus size and spot focus size at a 6 take 2 1 4 Focal Spot Brightness and Profile Focal spot brightness focal spot profile and X ray optics discussed in the next section influ ence X ray beam intensity The focal spot brightness is determined by the maximum target loading more specifically by power per unit area Table 2 4 gives the maximum target load ing and brightness power per unit area for some typical sealed tubes as well as some rotating anode sources equipp
57. may not accurately represent the angular position of measurement In this case the new 2D method should be used for stress calculation from the diffraction profiles generated at various y angles with a relatively small y Since the diffraction data includes both stress and texture informa tion 2D detectors also make it possible to mea sure stress and texture simultaneously This is necessary for corrections on the elastic anisot ropy caused by texture weld 718 XSI ress Nwe 1218608 008 Q5 13 9R 13 39 06 Created 10 17 97 Wag Quad i 4 Omega 36 000 width 0000 Counts 64 49 3 Time s 60 006 Nis lance 15 140 3 Size 1074 2 rrame was taken at No Weak 2 Theta 230 00 2 texture texture Omega 36 000 Phi 0000 2 chi 30 000 M x 14 993 2 stron Y 20 787 care g z 16 400 1 Aux 1 000 1 2 miss the diffraction ring Point detector or PSD will Disi ane e 10 000 Floodrid 1024 010 5patial 1024 010 1024x1024 No PLK Figure 6 7 Frames collected from samples with various degrees of texture from random powder to very strong texture With the very strong textured sample a conventional diffractometer may miss the diffraction ring M86 E01007 6 11 Residual Stress GADDS User Manual 6 1 5 Parameters The parameters required for X ray stress deter mination are crystal lattice parameter d spac ing Miller index X ray wavelength target material non stress two theta 209 Young s modulus E Poisson s ra
58. monitoring auto mission or reflection mode matic mapping grid for flat alignment and video moni matic mapping grid for flat samples transmission or toring transmission or samples transmission or reflection mode reflection mode reflection mode Phase ID Yes powder and small Yes especially for phase Yes powder and small Yes especially for phase sample preferred ID mapping sample preferred ID mapping Texture Pole figure or fiber plot o Pole figure or fiber plot Pole figure or fiber plot Pole figure or fiber plot and or scan for orienta scan only mapping ability and or scan for orienta choice of o y and scan tion coverage tion coverage for orientation coverage Stress Stress or stress tensor Stress or stress mapping Stress or stress tensor Stress or stress tensor o and 6 scans for stress ten o scan only and 6 scans for stress ten y and scans for stress Sor sor tensor Percent Yes Yes mapping capability Yes Yes mapping capability Crystallinity Micro Yes optional microdiffrac Yes mapping capability Yes optional microdiffrac Yes mapping capability Diffraction tion collimators are tion collimators are required required Thin Film Yes Yes mapping capability Yes Yes mapping capability Small Angle Optional helium beam path or vacuum beam path is required G bel optics is preferred for high resolution Scattering High Optional high temperature attachment is required Temp
59. near the amorphous region in the frames unless it is present under the crys talline line position The example in Figure 5 7 shows the effect of X ray absorption on pole figures The more pene trating Mo radiation samples more grains in the highly absorbing tungsten resulting in a smoother pole figure than obtained with Cu While the texture is qualitatively similar for each radiation it is not necessarily the case that the subsurface texture of the material is identical to its surface texture unless the sample has been prepared according to ASTM standard E81 90 Standard Test Method for Preparing Quantita tive Pole Figures which applies only to metals The sample surface texture could be the result of a machining operation such as cross sec tioning or grinding M86 E01007 GADDS User Manual Texture Figure 5 7 110 and 200 pole figures from a tungsten W cylinder collected with Mo and with Cu radiation Data was collected from the curved portion of the cylinder M86 E01007 5 15 Texture GADDS User Manual When merging multiple segments for a pole fig ure absorption corrections must be applied An empirical and an analytical method of absorp tion correction exist In the empirical method a reference pole figure is collected from a ran domly oriented specimen of the same material as the textured specimen This method is valid for infinitely thick samples in reflection or fibers and films in
60. or 0512 The fifth default digit is an underscore _ The last three digits stand for the sample to detector distance in cm e g 006 stands for the sample to detector distance close to 6 cm Using the filename as is without pathname the GADDS software will write the file to the frames default directory which enables the software to automatically reload the file If you want the file written to a different directory include that path name before the filename A o If using the glassy iron foil check enable the Open amp close shutter checkbox If using the Fe 55 source uncheck disable it Set the appropriate data fields to collect long enough to reach 10000000 counts for the total detector area Press the OK button to start data collection After the measurement is done the Flood Fld entry in the GADDS window displays the new correction table e g 0512_010 _fl Mount the brass plate to the detector sur face Ensure that the two pins on the detector fit the two mid size holes of the plate the elongated midsize hole is oriented to the negative 2 theta direction and the flat brass plate surface faces the detec tor window M86 E01007 Basic System Operation GADDS User Manual 3 4 2 Spatial Correction Using the same system setup and bias settings as for the flood field data collection perform the following steps 1 Left click Process gt Spatial gt Linear to dis able any e
61. send library information we create a script file called LibraryABC sIm We ll use the Project gt Edit command to send the library information but you could also use the Project gt New com mand which will use different folders for each library First create the script file with the library infor mation such as sample library information e g plate ID barcode technician s name You are limited to five lines of 72 characters each Example 11 4 Script file of library information File LibraryABC slm MCP created script 05 Nov 2002 Operator K Smith Project Edit amp Title Default well title 2 amp Formula Library title 1 amp Morph Library title 2 amp CCOL Library title 3 amp Density Library title 4 amp Densmeth Library title 5 Then execute this script by sending the win socket command M LibraryABC Next create the title information file containing sample information for each well Without this file the default well title is used for all wells You are limited to eight lines of 72 characters each Example 11 5 Title information file MCP created script 05 Nov 2002 Operator K Smith AO01 Title 1 for well A01 A01 Title 2 for well A01 etc up to 8 lines A02 Title 1 for well A02 etc H12 Title 1 for well H12 H12 Title 2 for well H12 etc up to 8 lines M86 E01007 Automation GADDS User Manual When GADDS moves to the next targ
62. shows that the data is good for biaxial stress tensor including the components 644 042 and 655 The scheme function can be used for a more compli cated data collection strategy to reduce the data collection time and still achieve the best result Prolect File Edit Collect Process Analyze Peaks Special User Help Figure 6 10 The 2D scheme plot simulated from the parameters in Figure 6 9 The diffraction vectors are clustered along S direction O GADDS General Area Detector Diffraction System 4 1 00 Copyr 1997 2000 Bruker Prolect File Edit Collect Process Analyze Peaks Special User Help Figure 6 11 The 2D scheme plot simulated from the same scan at 0 45 and 90 The diffraction vectors are distributed in S4 S2 and 45 directions The data is good for biaxial stress tensor M86 E01007 Residual Stress GADDS User Manual 6 1 8 Data Collection Procedures 1 Load sample Load the sample in a way that when o is in 90 position the incident beam hits the sample sur face in the perpendicular direction The sample coordinates are so defined that when o is set at 0 position S4 is opposite to the incident beam direction S is on the c rotation axis and S5 is the normal of the sample surface If the laser video sample alignment system is available the sample surface Z position should be aligned by bringing the laser spot to the center of the reti cule see Figure 6 22 2 Check coll
63. sub command or never take a sub command The combination of command and sub com mand directly relates to an entire dialog box in menu mode A few commands are only available in command mode and do not have corresponding dialog boxes such as the comment and the execute script com mands You may abbreviate the subcom mand but it must have enough characters to be distinguished it from all other subcom mands and qualifiers used for this verb Arguments The remaining components parameters and both types of qualifiers are collectively referred to as arguments Each argument consists of an argument name an argument value or both All argument names must begin with the slash character and have the form lt name gt All argument values consist of either a text string or a number Any argu ment value that contains slashes or embed ded spaces must be enclosed within double quotations for example TITLE My title has slashes and or spaces Some argu ments are required and if missing the pro gram will display that command s dialog box and wait for user input Missing non required arguments are defaulted to either the current default value or to N for Yes No input arguments Parameters Parameters consists of only an argument value and are recognized by the order in which they appear in the argument list In the command syntax descriptions in this manual N is used to refer to the Nth parameter in the list f
64. surface is g fee anti scattering sample pinhole 1 pinhole 2 Pinhole f d Ta dip Figure 2 6 Schematic of the beam path in a pinhole collimator showing the parallel divergent and convergent X rays and beam spot on sample surface The beam consists of three components paral lel divergent and convergent X rays The paral lel part of the beam has a size of d all the way from focus to sample The anti scattering pin hole is used to block the X ray scattering from the second pinhole The size of the anti scatter ing pinhole must be such that it allows no expo sure to direct rays from the focus M86 E01007 GADDS User Manual System Configuration The maximum divergence angle p is given by _ 2d p h 2 1 The maximum angle of convergence a is given by a E d h g 2 2 The maximum beam spot D on a flat sample facing the X ray source is given by D a 1 42 As shown in the equation the shorter the dis tance between the second pinhole and the sam ple or the longer the distance between two pinholes the smaller the beam spot on the sample The effective beam focus size fis determined by the pinhole distance h and the distance between the X ray source and the pin holes t a 28 1 h 2 4 If the actual X ray source F is larger than the effective focus size f the difference between F and f represents the wasted X ray energy Sometimes a micro focus tube is required
65. switch to merge adjacent frames in 20 and the same range in y 5 Use the Add Subt feature in the optional DIFFRACP SEVA toolbox to merge the adjacent frames in y and overlapping in 20 Alternatively use a profile fitting technique to obtain the integrated area for both the crystalline and amorphous peaks Remem ber to subtract the intensity contribution caused by Compton scattering before obtaining the integrated area for the amor phous and crystalline peaks The following discussion applies to a single fila ment or a carefully prepared fiber bundle Prep aration of a multiple fiber bundle should be done So that all of the fibers are oriented in the same direction and under the same tension Loose fil aments are undesirable Keep in mind that the X ray beam is only 0 5 mm or less in diameter so every fiber contributes to the diffraction pat tern Polymer percent crystallinity measure ments are performed in transmission Remember to use the beam stop The collimator size should be selected that is as near as possible to the diameter of the sample This reduces parasitic air scatter The trade off here is that for single fila ments which are typically under 50 um in diameter data collection times may be pro hibitively long As a compromise use a larger collimator and subtract a background frame collected under the same conditions in the absence of the sample Collect a background frame using a length of
66. system to block the direct beam from hitting the detec tor commonly in transmission mode diffrac tion Body Centered Cubic A crystal structure found in some metals Within the cubic unit cell atoms are located at all corners and cell center positions M86 E01007 Nomenclature and Glossary GADDS User Manual Bragg Law An equation that defines the diffraction con dition based on the relationship among the X ray incident angle to a crystal plane reflection angle from the crystal plane crys talline plane d spacing and the X ray wave length Characteristic Line X rays of definite wavelengths characteris tic of a pure substance generally a metal and produced when that substance is bom barded by fast electrons The typical char acteristic lines from an X ray generator are Ka Ka and Ka and Kf lines Collimator A device for producing a parallel beam of radiation Crystal A solid having a regularly repeating three dimensional array of atoms ions or mole cules Crystal Plane The repeating two dimensional atomic arrangement within a crystal Also called lat tice plane Crystallinity For polymers the state wherein a periodic and repeating atomic arrangement is achieved by molecular chain alignment See also percent crystallinity Detection Circle The scanning circle of a point detector within the diffractometer plane Detector Angle The detector swing angle is a right
67. the GADDS software left click Edit gt Configure User Settings see Figure 3 1 Enter the sample to detector distance noted in Figure 3 1 and choose either 1024 or 512 framesize 1024 is recom mended Options for Edit Configure User Settings x General User name Bruker Instrument Administrato Ste BrkerRXS Calibrationdatadirectory GADDSSCALIB 0 Minimum Po cps Timeout fio sec Characters in base frame name Characters in Run r Filename generation Temperature Controller Low temp device Y N Current temperature h n Base of Run Characters in Frame HTE Base of Frame Detector Direct beam X unw Direct beam Y unw Framesize Sample to detector face fi 4 850 cm 512 50 pixels 514 83 pixels fi 024 x Figure 3 1 Edit gt Configure gt User Settings window M86 E01007 GADDS User Manual Basic System Operation 3 4 Detector Aberration Analysis Before routinely collecting data with the D8 DIS COVER with GADDS you must perform a detector analysis which involves a flood field correction and a spatial correction In perform ing these corrections GADDS creates correc tion tables The flood field table is used to correct for inhomogeneities in the wire of the detector grids The spatial table is used to com pensate for parallax effects caused by the finite distance between detector grids and flatness of
68. the X ray illuminated vol ume V by the following transformation A G Ag d Jeep ga gt q is the scattering vector with modulus q gt 4r gt q sin0 Ae 4 is the scattering ampli tude of a single electron r is the vector that defines the position of a point relative to an arbi trary origin and p is the spatial distribution of electron density SAXS deals with the size range well above the interatomic distance so that p can be approximated as a continuous variable of the position T in the specimen The actual measured intensity is given by the prod uct amplitude 4 7 and its complex conju gate A4 4 K A A Q Ip pter ni v 9 2 where h is a constant defined by the conditions of the SAXS instrument The intensity distribu tion SAXS pattern as a function of 7 is uniquely determined by the structure in terms of its electron density distribution In principle the structure can be uniquely determined from the SAXS pattern For instance if the scattering is spherically symmetric i e 7 depends only on q then we have Kq 4z pin 8t dr 0 where p r is the so called pair distance distribu tion function PDDF which gives the number of difference electron pairs with a mutual distance between rand r ar within the particle We can see that like the electron spatial distribution 9 3 function p n p r is a function of the structure p r is given by the
69. the other lt 111 gt family members is 70 5 which is verified in the FTP by the second intensity peak It is important to remember that the crystallographic system of the film dictates where intensities are expected to be observed in FTPs The reciprocal and direct real space crystallographic directions are only coincident in cubic systems For example in Ti which has a hexagonal lattice the 100 reciprocal lattice plane is perpendicular to the 210 direction not to the 100 direction Ta Nsubstrate hkl M86 E01007 Texture GADDS User Manual The shape of the FTP curve provides a simple qualitative picture of the fiber or near fiber tex ture The area under the FTP can be integrated to obtain a quantitative representation of the tex ture strength from which pole spread and or pole tilt can be quantified With appropriate background correction of the measured raw data the linear background under the FTP can be used to quantify the percent random distribu tion of the grains Texture quantification is reported as the volume fraction or half width gg and 59 where o represents the half angle in degrees in which a specified fraction of the intensity 90 50 is contained For example the half angle containing 50 of the 111 grain orientations is c9 From this definition the smaller the value for oso the narrower the 111 grain distribution the smaller the pole spread and the stronger the texture Fo
70. type This allows fine adjustment of the physical fiber axis with respect to the goniometer axis The wax should have good adhesion prop erties at temperatures up to 40 C and should not undergo elastic relaxation 7 Align the physical fiber axis vertically using the two position y stage or the fixed y stage with an adapter mount With this arrange ment you can observe a meridional reflec tion up to 30 with the detector at 6 cm For M86 E01007 8 13 Percent Crystallinity GADDS User Manual Percent Crystallinity of a Sheet Polymer sheet data collection is similar to that for reflection samples The difference is that in transmission with the detector at 6 cm the com plete Debye rings are on the detector The prep aration of the specimen is very important To mount polymer films that are rigid you can clip and hold them in place using a small alligator clip and mount the clip to a goniometer head If the film is not rigid you may be able to trim the piece and mount it in the fiber paper clip frame The width of the sheet should be equal to the sheet thickness if possible Otherwise the reflections arising from planes parallel to the surface will not be proportional in intensity to those out of plane The total transmitted inten sity is a linear function of the sample thickness t multiplied by an attenuation factor ut ltransmitted 0 te where u is the linear absorption coefficient of the mate
71. used during the mea surement for approximately 30 minutes prior to final beam stop adjustment 2 Partof the direct beam is observed In this case move the beam stop to block the direct beam 3 The direct beam is not obscured by the beam stop In this case follow correc tion in 2 above For 1024x1024 frames with MAG 1 each pixel is approximately 100 um Use the vec tor cursor to determine the number of pixels from the beam center to the beam stop cen ter and adjust the micrometers accordingly To finely align the beam stop set the gener ator power to the level to be used for data collection and make any necessary adjust ments as follows Assuming perfectly aligned pinholes the scattering about the X ray axis is symmetrical Therefore remain ing scatter around the beam stop if any should also be symmetrical If the pinholes are not perfectly aligned or positioned the asymmetrical parasitic scattering will be evident With an Anton Paar HR PHK you can eliminate this parasitic scatter by adjust ing the guard pinhole whose micrometer adjustments are located inside the sample chamber For G bel Mirrors and pinhole col limator systems adjust the beam stop to eliminate as much of this scattering as pos sible M86 E01007 GADDS User Manual Small Angle X ray Scattering Calibrating the Beam Center and Detector 2 Collect a calibration frame using silver Distance behenate powder sample as shown in Fig
72. value is calculated open the first frame in GADDS or move back to the first frame by pressing the Ctrl lt keys a few times M86 E01007 25 Residual Stress GADDS User Manual 2 Select Analyze gt Stress gt View 2D to acti vate the data display menu Figure 6 20 Input the following parameters by following the instructions at the bottom of the GADDS window STRESS VIEW options x 7 M M Figure 6 20 Stress result display menu 6 26 M86 E01007 GADDS User Manual Residual Stress 3 Click on OK to display the data one by one with the defined movie delay time see Fig ure 6 21 7 GADDS General Area Detector Diffraction System V4 A 02 Copyr 1997 98 Bruker Project File Edit Collect Process Analyze Peaks Special User Help Figure 6 21 The stress data points and the simulated diffraction ring corresponding to the measured stresses are displayed on the frame Stress on Almen Strip HRC 2 frames strsnorm 000 02 25 99 16 52 05 Created 07 29 98 Mag Quad 1 0 Omega 57 000 width 0 0000 Counts 138328 Time s 60 006 Distance 14 900 Size 1024 Frame was taken at Young Poisson Arx Sigma Sigma Sigma Sigma Distance FloodFld Spatial 1024x1024 7 6 6 5 4 4 3 3 2 2 M86 E01007 Residual Stress GADDS User Manual 6 4 Application Examples 6 4 1 Example 1 Conventional Method Residual Stress Measurement with GADDS Microdiffraction Syst
73. when a small beam size is used The actual beam divergence is also determined by the monochro mator and mirrors advancing the collimator in the beam path For example when cross cou pled G bel mirrors are used the X ray beam is almost a parallel beam and the divergence of the beam is smaller than the value calculated from equation 2 1 When the actual beam focus on the source f is smaller than f we have the following equations to calculate the maxi mum divergence f convergence a and beam spot size on sample D rs 225 2 5 T7 Heo 2 6 D B H g f 2 7 Table 2 7 lists the values of beam divergence convergence and beam spot on sample for a system with a 0 4 mm x 0 8 mm fine focus tube The graphite monochromator has a rocking curve of 0 4 and cross coupled G bel mirrors of 0 06 The beam divergence and conver gence angles should not be above these values M86 E01007 System Configuration GADDS User Manual Table 2 7 X ray beam divergence angle B convergence angle a and beam spot size on sample D for a 0 4 mm point focus tube with graphite monochromator or cross coupled G bel Mirrors Collima Graphite Monochromator G bel Mirrors tor Size d mm BO a D mm f mm B a D mm 0 05 0 041 0 017 0 07 0 15 0 041 0 017 0 07 0 10 0 082 0 034 0 14 0 30 0 060 0 034 0 13 0 20 0 164 0 067 0 29 0 60 0 060 0 060
74. y integrated profile is an average over the Debye ring defined by the y range The average effect is over a region of ori entation distribution rather than a volume distri bution Figure 6 5 The relationship between the y integration range Ay and the virtual oscillation angle Ay The virtual oscillation angle Ay can be calcu lated from the integration range Ay and Bragg angle 0 AY 2arcsin cos sin Ay 2 6 7 M86 E01007 Residual Stress GADDS User Manual For example Figure 6 6 is a frame taken from a stainless steel with large grain size If we inte grate from y 80 to 100 Ay 20 0 64 the virtual oscillation angle Ay 8 7 In the conven tional oscillation mechanical movement may results in some sample position error Since there is no actual physical movement of the sample stage during data collection the virtual oscillation has no such problem 05 12 98 Created Mag Quad Omega width Counts Time s Distance Size 2th begi 2th en chi begi chi en I n t e n s i t y Distance FloodFld Spatial 1 2 3 4 Select edge M Move ENTER L button Integrate Figure 6 6 A diffraction frame taken from a stainless steel The virtual oscillation by y integration over Ay 20 gives a smooth diffraction profile When the 2D method is used for stress mea surement the virtual oscillation effect is further enhanced due to the larger y range It is more important that th
75. 0 0 56 0 01 0 02 0 04 0 05 2 20 M86 E01007 GADDS User Manual System Configuration Table 2 23 Beam divergence 20 spread in asa function of and 20 with a 0 8 mm collimator 6 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm qe 40 20 40 60 80 100 120 140 160 IE 51 33 023 0 69 143 2 76 3 76 4 31 4 34 884 2 88 1 57 2 25 67 0 08 0 31 0 68 1 35 1 86 2 15 2 17 1 94 1 47 0 82 5 10 28 0 08 0 23 0 50 0 72 0 85 0 88 0 80 0 62 0 37 10 5 16 0 08 022 0 34 0 41 0 44 O 41 0 34 0 22 20 2 62 0 08 0 14 0 19 0 22 0 22 0 19 0 14 30 1 79 0 03 0 08 0 12 0 14 0 15 0 14 0 12 40 1 39 0 04 0 08 0 10 0 12 0 12 0 10 50 147 0 02 0 05 0 08 0 09 0 10 0 09 9 oeo FL 0 01 0 04 0 06 0 07 M86 E01007 2 21 System Configuration GADDS User Manual 2 2 4 Single and Cross Coupled G bel Mirrors Recent developments in X ray optics include graded multilayer X ray mirrors known as G bel mirrors A cross coupled arrangement of these optics for the GADDS system provides a highly parallel beam which is much more intense than can be obtained with standard pin hole collimation and a graphite monochromator For applications such as microdiffraction where a small spot size is desired G be
76. 0 CHI 54 74 AXIS 2 amp 1 00 00 TITLE Corundum Test Sample amp SAMPLE 0 NAME corund RUN 0 FRAMENO 002 amp HI 0 0 CHI 54 74 AXIS 2 amp TLE Corundum Test Sample amp SAMPLE 0 NAME corund E Scan 1 2THETA 95 0 OMEGA 42 5 P E Scan E n OFFSE corund FOR E n OFFSE 000 75 000 00 60 000 NORMAL 3 MAT DIFFRACplus SCALE 1 0 RUN 0 FRAMENO 003 amp HI 0 0 CHI 54 74 AXIS 2 amp 1 00 00 TITLE Corundum Test Sample amp SAMPLE 0 NAME corund RUN 0 FRAMENO 004 amp r 0 0 STEPSIZE 0 1 r 0 0 NORMAL 3 STEPSIZE 0 1 corund FORMAT DIFFRACplus APPEND amp E n OFFSET 0 0 000 75 000 NORMAL 3 STEPSIZE 0 1 corund FORMAT DIFFRACplus APPEND amp E n OFFSET 0 0 000 75 000 NORMAL 3 STEPSIZE 0 1 corund FORMAT DIFFRACplus APPEND amp M86 E01007 10 11 Script Files GADDS User Manual 13 Add comments to the script file Comments start with a exclamation as the first char acter of a line Use comments to identify the script file s purpose history parameters if any and major steps PhaseID slm Qualitative Phase Identification Script File Version 1 0 Created by KLS 06Jan98 Last modified by no one This script will collect 4 frames at 20 45 70 95 deg integrate and merge results into a single range RAW file for input into EVA s search match routine n tep 1 define a new pro
77. 0 39 5 10 28 0 04 0 11 0 24 0 34 0 41 0 42 0 38 0 30 0 18 10 5 16 0 04 0 11 0 16 0 20 0 21 0 20 0 16 0 11 20 2 62 0 04 0 07 0 09 0 11 0 11 0 09 0 07 30 1 79 0 01 0 04 0 06 0 07 0 07 0 07 0 06 40 1 39 0 02 0 04 0 05 0 06 0 06 0 05 50 1 17 0 01 0 02 0 04 0 05 0 05 0 05 90 0 90 0 01 0 02 0 03 0 03 Table 2 20 Beam divergence 20 spread in as a function of and 20 with a 0 2 mm collimator 6 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 1 40 20 40 60 80 100 120 140 160 1 12 83 0 06 0 17 0 36 0 69 0 94 1 08 1 08 0 96 0 72 0 39 2 6 42 0 02 0 08 0 17 0 34 0 47 0 54 0 54 0 48 0 37 0 21 5 2 57 0 02 0 06 0 13 0 18 0 21 0 22 0 20 0 16 0 09 10 1 29 0 02 0 06 0 08 0 10 0 11 0 10 0 08 0 06 20 0 65 0 02 0 04 0 05 0 06 0 06 0 05 0 04 30 0 45 0 01 0 02 0 03 0 04 0 04 0 04 0 03 40 0 35 0 01 0 02 0 03 0 03 0 03 0 03 50 0 29 0 01 0 02 0 02 0 03 0 02 90 0 22 0 01 0 01 0 02 M86 E01007 System Configuration GADDS User Manual Table 2 21 Beam divergence 20 spread in as a function of and 20 with a 0 3 mm collimator 6 cm sample to detector distance and 1024x1024 frames
78. 0 826 422 Cu 137 7 Copper fcc 3 615 1 278 220 Cr 127 8 129800 0 343 1 09 1 044 222 Co 118 1 0 829 331 Cu 136 7 o Brass fcc 3 680 1 901 220 Cr 123 4 100600 0 350 0 920 400 Co 153 2 0 823 420 Cu 139 1 p Brass bcc 2 945 1 202 211 Cr 144 6 74000 0 290 0 930 310 Co 146 4 0 850 222 Cu 130 1 Chromium bcc 2 884 1 177 211 Cr 153 0 279000 0 210 1 020 220 Co 122 7 0 912 310 Cu 115 3 Nickel fcc 3 529 1 248 220 Cr 133 7 199500 0 312 1 52 1 019 222 Co 122 9 0 810 331 Cu 145 0 M86 E01007 6 13 Residual Stress GADDS User Manual Materials a c duy HKL Target 20 E n Arx Parameter A A degree MPa Titanium c hep 2 951 4 686 1 247 112 Cr 138 8 120200 0 361 0 918 114 Co 154 6 0 821 213 Cu 139 5 Manganese hcp 3 210 5 210 1 366 112 Cr 113 9 44700 0 291 0 976 105 Co 133 1 0 899 213 Cu 118 0 Molybdenum bcc 3 147 1 285 211 Cr 126 0 324800 0 293 0 995 310 Co 128 0 0 841 321 Cu 132 6 Niobium bcc 3 307 1 348 211 Cr 116 3 104900 0 397 1 045 310 Co 117 7 0 884 321 Cu 121 2 Silver fcc 4 086 1 231 311 Cr 136 9 82700 0 367 0 938 331 Co 145 2 0 834 422 Cu 134 9 Gold fcc 4 079 1 230 311 Cr 137 1 78000 0 440 0 936 331 Co 145 8 0 833 422 Cu 135 4 Tungsten bcc 3 165 1 292 211 Cr 124 9 411000 0 28 0 914 222 Co 156 8 0 791 400 Cu 155 0
79. 007 GADDS User Manual Nomenclature and Glossary 13 2 Glossary 2D Detector Two dimensional detectors such as multi wire area detector CCD detector and image plate 2DXRD Two dimensional X ray diffraction system alternatively XRD Absorption As an X ray beam passes through a sam ple in addition to the scattered beam and transmitted beam its intensity is also reduced by absorption The extent of absorption depends on the path length of the beam through the sample the nature of the material and the wavelength of the inci dent X ray beam Anisotropic Factor A factor that represents the different physi cal properties in different crystal direction In this manual the anisotropic factor Apy is used for stress calculation Anode X ray The electrode in an X ray generator which emits X rays when bombarded by fast elec trons Also called target Area Detector A device for measuring 2D two dimen sional diffraction pattern at one time It can be a CCD detector image plate or multiwire detector In this manual it specifically refers to the Hi Star multiwire area detector Attenuation The intensity reduction of an X ray beam after passing though a material or a device attenuator Backward Diffraction The diffraction condition when 20 gt 90 Beam Center The pixel position of the direct beam on a 2D detector sitting at on axis position Beam Stop A device used in a diffraction
80. 07 Script Files GADDS User Manual 4 Place GADDS into auto script mode using the File gt ScriptFile command Give a file name of PhaselD and an Append value of N unchecked GADDS will automatically add the slm extension to the filename Script filename PhaselD Append Y N I Check for yes Figure 10 1 Options for File Scriptfile l 5 For GADDS 3 X users skip to step 6 For PERETE GADDS 4 0 users each sample should EN reside in a separate project Alternatively Crystal Number upto 4digits 0 22 you may consider the project to be qualita Title Corundum Test Sample tive phase identification and thus all sam m ples would belong to that project Use the Working Directory SPROJECT 0 Project gt New command Give a new values for Project information and Directory infor r Crystal Information Y PR mation parameters You may set Crystal crearet sss aasa information parameters to Cystal Coorp S SSS Maximum Dimension Intermediate Dimension MinmumDimension C lt CS 7 7 7 7 7 7 lt Measured Density DeniyMetod SOS Clear Crystal info Y Reset to defaults Y Figure 10 2 Options for Project New 30 8 MB86 E01007 GADDS User Manual Script Files 6 Collect first frame using the Collect gt Scan gt SingleRun command Start at 20 degrees in 20 and scan in w from 5 to 15 degrees Collect the second frame usin
81. 090 only the defocusing effect with reflection mode diffraction can be expressed as B _ sin 20 b sino 2 8 where o is the incident angle b is the incident beam size and B is diffracted beam size The defocusing with transmission mode with a perpendicular incident beam can be given as B D cOS20 4 sin20 where tis the sample thickness If the sample thickness tis negligible compared to the incident beam size b we have B cos20 lt 1 b 2 10 There should be no defocusing effect at all M86 E01007 System Configuration GADDS User Manual Figure 2 24 is a comparison between reflection mode and transmission mode diffraction with data frames collected from corundum powder With 5 incident angle a the reflection pattern shows severe peak broadening compared with no defocusing in transmission mode pattern b GADDS General Area Detector Diffraction System 4 1 11 Copyr 1997 2002 Bruker GADDS General Area Detector Diffraction System V4 1 11 Copyr 1997 2002 Bruker Project File Edit Collect Process Analyze Peaks Special User Help Project File Edit Collect Process Analyze Peaks Special User Help Figure 2 24 Diffraction pattern from corundum a reflection mode diffraction 5 incident angle b transmission mode diffraction with perpendicular incident beam 2 50 M86 E01007 GADDS User Manual System Configuration In many combinatorial screening applications such as
82. 2 0 04 0 08 0 11 0 13 0 13 0 11 0 09 0 05 2 1 60 0 01 0 02 0 04 0 06 0 06 0 07 0 06 0 04 0 02 5 0 64 0 01 0 02 0 02 0 03 0 03 0 02 0 02 0 01 10 0 32 0 01 0 01 0 01 0 01 0 01 0 01 0 01 20 0 16 0 01 0 01 0 01 0 01 30 0 11 40 0 09 50 0 07 90 0 06 2 16 M86 E01007 GADDS User Manual System Configuration Table 2 15 Beam divergence 20 spread in as a function of o and 20 with a 0 1 mm collimator 15 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 40 20 40 60 80 100 120 140 160 1 6 42 0 01 0 04 0 09 0 17 0 23 0 26 0 26 0 23 0 17 0 09 2 3 21 0 02 0 04 0 08 0 11 0 13 0 13 0 12 0 09 0 05 5 1 28 0 01 0 03 0 04 0 05 0 05 0 05 0 04 0 02 10 0 64 0 01 0 02 0 02 0 03 0 02 0 02 0 01 20 0 33 0 01 0 01 0 01 0 01 0 01 0 01 30 0 22 0 01 0 01 0 01 0 01 0 01 40 0 17 0 01 0 01 0 01 0 01 50 0 15 0 01 0 01 0 01 90 0 11 Table 2 16 Beam divergence 20 spread in as a function of o and 20 with a 0 2 mm collimator 15 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 40 20 40 60
83. 3 7 2 Add or Rotation Method sdy ea irae e EE KEA E a e RA E 3 24 3 8 Basic Data Analysis and Preparation 0 cee tee 3 25 4 Phase lD a gcc e ern ricer owe teenie area odia eure 4 1 4A Overview cuni mk REG Resa Sede eee DE eee doe ee A 4 1 4 2 Performing a phase ID analysis 0 0 cee en 4 6 M86 E01007 1 05 GADDS User Manual Table of Contents GMUIDOQU ee ee ee a ee ee ne ee ee 5 1 5 T OVelVieW x ocupa ieu estu ye eA e bee Rem NP A Pci ae huis bag 5 1 5 2 General Data Collection Considerations for Texture Analysis sesion 5 7 5 3 Preparation for the Texture Experiment 20 00 00 cee eren 5 9 5 4 Data Collection Considerations for ODF Analysis 0000 cece eee eee 5 10 5 5 Other Texture Representations 0 0 0 nns 5 11 5 6 Using POLE FIGURE SCHEME to Plan Strategy and Coverage 0 5 5 11 5 7 Using POLE FIGURE PROCESS sss ren 5 13 5 8 Polymer Orientation x pranise ea a E a rrr 5 17 5 9 Fiber Orientation iire nanei bi he Pee Seed tend 44x bel Meda a ae Pag Ps 5 18 5 10 Sheet Orientation lt lt i dacodacGad bead eei Peewee Seed eee REP A NO ete dbase 5 20 5 11 Near Single Crystal Thin Film Orientation 0 0000 0c eee 5 21 5 12 Semiquantitative Analysis with CURSOR Commands 0 00 e eset eee 5 22 5 13 Preparation for ODF Analysis with popLA and ODF AT 000 0c cence eee 5 23 5 14 Hermans and White Spruiell Orientation Indi
84. 4 0 01 0 01 0 02 0 02 0 02 90 0 34 0 01 0 01 0 01 Table 2 18 Beam divergence 20 spread in as a function of o and 20 with a 0 5 mm collimator 15 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 1 10 20 40 60 80 100 120 140 160 1 32 08 0 07 0 21 0 43 0 83 1 13 1 29 1 30 1 15 0 86 0 47 2 16 04 0 02 0 09 0 20 0 40 0 56 0 64 0 65 0 58 0 44 0 25 5 6 42 0 02 0 07 0 15 0 22 0 25 0 26 0 24 0 19 0 11 10 3 22 0 02 0 07 0 10 0 12 0 13 0 12 0 10 0 07 20 1 64 0 02 0 04 0 06 0 07 0 07 0 06 0 04 30 1 12 0 01 0 02 0 04 0 04 0 05 0 04 0 04 40 0 87 0 01 0 02 0 03 0 04 0 04 0 03 50 0 73 0 01 0 02 0 02 0 03 0 03 0 03 90 0 56 0 01 0 02 0 02 M86 E01007 GADDS User Manual System Configuration Table 2 19 Beam divergence 20 spread in asa function of o and 20 with a 0 8 mm collimator 15 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 40 20 40 60 80 100 120 140 160 1 51 33 0 11 0 33 0 68 1 32 1 80 2 06 2 08 1 84 1 38 0 75 2 25 67 0 04 0 15 0 32 0 65 0 89 1 03 1 04 0 93 0 70
85. 4 Remote control Phase 5 Audit trails Phase 5 Audit trails M86 E01007 Automation GADDS User Manual 11 1 Primitive Automation Let us examine automation with a practical example Assume we have a typical GADDS CS configuration i e theta theta geometry XYZ stage and laser alignment option which is ideal for high sample throughput Our samples are prepared in batches on sample libraries or plates Libraries can come in 24 48 or 96 well sizes Our libraries are 96 well Each well is labeled starting at A01 and ending at H12 Each plate has identification and possibly a bar code When a library of samples is produced plate information sample information and the bar code is entered into a database Our task is to perform Phase Identification on each sample First we will automate the handling of a single library Assume we have a guide on our XYZ stage so the library loading can be reproduced Map the well centers for wells A01 and H12 using the Scan GridTargets command and input the distance between each target in the grid increment The run target numbers are changed to the well id i e A01 to H12 Set run chars to three and run base to 36 in Edit gt Configure User Settings to properly record the well id In the following example a 96 well plate will be measured using a coupled scan mode two frames per sample with a 2 theta deviation of 20 The measurement angles frame width and sc
86. 6 E01007 Basic System Operation GADDS User Manual 3 4 Starting the System 3 1 1 D8 Series I K760 Generator 1 Turn on the generator See the generator manual for details on operation and diagno sis A CAUTION Increase high voltage and current in small steps for maximum tube life 2 Turn on the D8 controller or GGCS for PLATFORM systems with the enclosure Power button and log on to your computer Turn on the PDC HI STAR controller Start the GADDS software Start the GADDS software Wait for the pro gram to establish a connection to the goni ometer 6 Goto Collect Goniometer Generator Ramp up the generator voltage and current to your settings Give the generator s high voltage a minute to stabilize NOTE The argument provided in the Windows NT shortcut command defines the hardware configuration of the D8 DISCOVER with GADDS e g information about the installed sample stage the sample alignment tool etc The parameter nodiff disables communication with the Phoenix GGCS for this GADDS task It is often used for data evaluation while a new measurement is running See the Running GADDS section of M86 Exx008 GADDS Soft ware Reference Manual for further details 3 1 2 D8 Series II K780 Generator 1 Turn on the D8 controller with the green enclosure Power button 2 Turn on the generator high voltage by turn ing the switch clockwise Wait until you hear a click Turn on th
87. 7 shows the result from a phase identi fication measurement on ZrO ZrO2 9cm 50s a AR D a E N O 1024x1024 Cu Bias o o Lin Counts li f Thi E i T r M he PUR ge rp 1 Lees yu i rity ttt trp ere Poet ral ity yt OAFANWHKUADN 26 30 40 50 60 70 2 Theta Scale WlNew Frame File DUP zro2 9 2 raw Type 2Th alone Start 25 800 End 76 000 Step 0 010 Step time 50 0 s Temp 25 0 C Ro Operations X Offset 0 125 Import 137 1484 Baddeleyite syn ZrO2 Y 155 00 d x by 0 998 WL 1 54056 Figure 4 7 Phase identification measurement 4 8 M86 E01007 GADDS User Manual Phase ID XRD phase identification on very small samples is called Microdiffraction Due to its high speed and sensitivity the D8 DISCOVER with GADDS is ideal for these usually extremely time con suming applications The system can measure with beam diameters as small as 50 microns Figures 4 8a through 4 8c show typical applica tions for forensic work The measurements were performed on a 20 micron wire 4 8a different layers of a car paint 4 8b and on very small amount of different sands 4 8c NOTE See sections 10 3 and 10 5 for examples of creating a Phase ID script
88. AY NEW SAXI TEST cor30u 001 amp QUADRANT 0 LO 0 HI 100 amp X 255 Y 255 MAG 1 Because one purpose of script files is to operate the GADDS system in batch mode you do not wish to suspend the execution of a script when ever a warning condition exists Thus within script files warnings are displayed for only a few seconds before they time out and default to either OK or Yes You may override the time out by entering OK Yes or No at any time You can also control the command mode time out inter val by using the Edit gt Configure gt User Set tings GADDS 4 x or Edit gt Configure gt Edit GADDS 3 x command Finally do not confuse SLAM syntax with start up qualifier syntax While startup qualifiers which are used when starting GADDS from icon M86 E01007 GADDS User Manual Script Files 6699 or command prompt window allow either or between qualifier name and value SLAM only recognizes the convention Also SAXISSWCHAR can be used to override the default switch character for startup qualifiers but has no effect on SLAM qualifiers 10 2 Executing Script Files When the program is in command mode you can execute a script file by using the com mand which instructs the program to start accepting the SLAM commands within the script file as if each command was typed one at a time directly on the command line You must specify the name of the script file immediately aft
89. DDS User Manual Crystal Size 7 4 Data Collection for the Warren Averbach and Scherrer Methods Determination of all peak broadening due to instrumental parameters e g collimator size detector resolution beam divergence is critical Only peak broadening due to crystallite size can be considered in the crystallite size calculation The detector distance of 30 cm is chosen to maximize resolution and minimize peak FWHM due to detector resolution In this way peak broadening due to crystallite size is not obscured by instrumental peak broadening Data was collected with both a 0 1 mm collima tor and a 0 2 mm collimator with the same 20 and angles using LaBg Data collection times were adjusted to obtain comparable signal to noise No additional peak broadening of LaBg was observed with a 0 2 mm collimator above that observed with the 0 1 mm collimator It was observed that the 0 3 mm collimator did contrib ute additional peak broadening In crystallite size measurements on randomly oriented materials e g fine powders there is no reason to rotate or oscillate the sample If sample characteristics warrant sample rotation or oscillation e g the sample has preferred ori entation then the standard should be collected under identical measurement conditions NIST standard LaBg SRM 660 is used to determine instrument broadening With this standard all broadening is due to instrumental parameters With 99 of its part
90. DS User Manual where Epy is the measured strain in the orienta tion defined by and v angles and 44 42 22 43 23 and 35 are strain tensor components in the sample coordinates S S5S3 as shown in Figure 6 1 a a 95 S2 L Figure 6 1 Configurations for conventional stress measurement method a The relation between the measured strain and the sample coordinates S4S2S3 b Two kinds of v tilt In the equation 6 1 one 20 shift value d spac ing change is considered at each sample orien tation y This is suitable to the stress measurement with point detectors or one dimensional position sensitive detectors In the conventional stress measurement method the y tilt is achieved by two kinds of diffractometer configurations shown in Figure 6 1 b One is y axis Diffracted Incident beam beam Q rotation V rotation O diffractometer also called iso inclination configuration in which the w rotation axis is per pendicular to the diffractometer plane that con tains the incident and diffracted beams The other is y diffractometer or side inclination configuration in which the w rotation axis is in the diffractometer plane The sin2y method derived from equation 6 1 is most often used to calculate residual stress on the sample sur face in 9 direction og The details are described in 1 2 and the DIFFRAC 4S STRESS software manual M86 E01007 GADDS User Manual
91. E01007 2 3 System Configuration GADDS User Manual Table 2 2 Selection of target material with respect to the applications Target Typical Applications Ag Low absorption single crystal transmission diffraction with CCD detector Mo Low absorption single crystal transmission diffraction with CCD detector Cu Most powder diffraction stress texture thin films polymer SAXS single crystal Co Used for ferrous alloys steels to reduce Fe fluorescence ideal for residual stress Fe Used for ferrous alloys steels to reduce Fe fluorescence ideal for residual stress Cr Ideal for materials with large unit cell ideal for residual stress with high resolution 2 1 3 Focal Spot and Takeoff Angle The focal spot also called focal spot on target and takeoff angle are critical features in the pro duction of X rays by sealed tube and rotating anode generators Sealed tube and rotating anode generators produce X rays Figure 2 3 by bombarding the target sample with electrons generated from the filament cathode The area bombarded by electrons is called focal spot on target or simply focal spot and the angle between the primary X ray beam and the anode surface is called takeoff angle cathode T focal spot focus ee E jo takeoff angle spot focus Figure 2 3 Schematic of a sealed X ray tube showing filament cathode anode focal spot on anode takeoff angle projected
92. GADDS software Collect gt 20kV 5mA for sealed tube if the gen Goniometer Generator or press the erator is not in use for extended time Ctrl Shft G keys hours to days Table 2 5 Start up procedures for cold generator or new tube Pause in High Voltage Duration Total Operation time for days 55 kV 20kV 25 kV 30 kV 35 kV 40kV 45 kV 50kV 55kV 0 5 to 3 30s 30s 30s 30s 30s 30s 1min 2min 6 min 3 to 30 30s 30s 2min 2min 5min 5 min 10 min 10 min 35 min 300rnew 30s 30s 2min 2min 5 min 10 min 15 min 15 min 50 min tube M86 E01007 System Configuration GADDS User Manual 2 2 X ray Optics The function of X ray optics is to condition the primary X ray beam into the required wave length beam focus size beam profile and divergence The X ray optics components com monly used for GADDS systems and discussed in this section are a monochromator a pinhole collimator cross coupled G bel mirrors and a monocapillary Figure 2 4 shows an X ray tube a monochroma tor a collimator and a beam stop in a standard GADDS system It also shows the instrument center and the shadow of a fixed chi stage Using a point X ray source with pinhole collima tion enables you to examine small samples microdiffraction or small regions on larger samples selected area diffraction This config uration enables you to measure crystallographic phase texture
93. GLE RUN set 0 If the reflection occurs below 10 20 set 10 OY OT 9 Set scan axis equal 3 the axis Set step size for 2 Collect 16 frames Process the frames using POLE_FIGURE PROCESS without the FIBER option M86 E01007 Texture GADDS User Manual 5 10 Sheet Orientation Polymer sheet data collection is similar to that for reflection samples The difference is that with the detector at 6 cm the complete Debye rings are on the detector This reduces the number of required frames for pole figures by at least a fac tor of two The preparation of the specimen is very important For polymer films that are rigid it is possible to hold them in place using a small alligator clip mounted to a goniometer head If the film is not rigid a piece is often trimmed to mount in the same frame as the fiber The width of the sheet should be equal to the sheet thickness if possible otherwise the reflections arising from planes parallel to the surface will not be proportional in intensity to those out of plane The total transmitted inten sity is a linear function of the sample thickness t multiplied by an attenuation factor a ut ltransmitted o te where u is the linear absorption coefficient of the material Differentiating this equation the opti mal thickness of the sheet to obtain the maxi mum transmitted intensity is found to equal the inverse of the material s linear absorption coeffi ci
94. I 55 000 85 000 115 000 75 000 NORMAL 3 STEPSIZE 0 1 INTEGRATE WRITE TITLE FILENAME corund FORMAT DIFFRACplus APPEND amp SCALE 1 0 LOAD corund0 004 DISPLAY 63 SCALE n OFFSET 0 0 INTEGRATE CHI 80 000 110 000 115 000 75 000 NORMAL 3 STEPSIZE 0 1 INTEGRATE WRITE STITLE FILENAME corund FORMAT DIFFRACplus APPEND amp SCALE 1 0 E pH qu Q D H j a Q Step 4 merge multi range raw file into single range raw file SYSTEM GADDS SYSTEM merge corund raw corundMerged raw Step 5 spawn EVA and perform a search match operation n y i see your EVA manual on how to do this M86 E01007 10 15 Script Files GADDS User Manual 10 4 Using Replaceable Parameters within Script Files A replaceable parameter is an information placeholder that you add to a script file to permit automatic replacement of a different value for that parameter each time you run the script For instance you may want to insert a replaceable parameter for the script s title sample name or data files common uses of replaceable parame ters so that the script many be used for more than one sample Ten replaceable parameters are available 1 through 0 with 1 representing the first parameter 2 representing the second param eter and so forth You pass the information text for the replaceable parameter on the com mand used to invoke the script SLAM will replace all occurr
95. Mag Quad 1 0 Omega 50 000 width 250 Counts 193723 Time s 900 00 121 Distance 6 000 size 512 111 Frame was taken at 2 Theta 50 000 101 Omega 50 000 Phi 286 44 Chi 90 000 x 11 334 Y 7 995 zZ 1 781 Aux 6 877 Distance 7 460 FloodFld LINEAR Spatial test 512x512 HY Off thoose file function Figure 3 7 Screen during measurement M86 E01007 3 11 Basic System Operation GADDS User Manual GADDS software fits splines to the position of all local intensity maxima above the pre set threshold The splines describe a map function that moves the locations of the intensity maxima to the positions of the holes in the brass plate After the measurement is done the Spatial includes an X Y graph for pinpointing cen troids and a spotted grid with up to 19 rows and columns less for close sample to detector distances Each blue spot repre sents a centroid calculated from the spots of the transmitted rays The blue spots should form a regular complete and balanced grid slightly bowed toward the edges A grid missing spots along an edge as shown is acceptable However stray spots within or outside grid lines and jagged grid lines are not acceptable entry in the GADDS window displays the new correction table e g 0512_010 _ix On the screen appears a blue overlay see Figure 3 8 indicating that the software has analyzed the collected frame The overlay GADDS General Area Detector Diffrac
96. N UKER BRUKER ADVANCED X RAY SOLUTIONS MW General pee Detectot Diffraction System GADD Version duos USER MANUAL M86 E01007 1 05 NN UKER BRUKER ADVANCED X RAY SOLUTIONS General Area Detector Diffraction System GADDS User Manual Version 4 1 xx M86 E01007 1 05 This manual covers the GADDS software package To order additional copies of this publication request the part number shown at the bottom of the page 2005 1999 Bruker AXS Inc All world rights reserved Printed in the U S A Notice The information in this publication is provided for reference only All information contained in this publication is believed to be correct and complete Bruker AXS Inc shall not be liable for errors contained herein nor for inciden tal or consequential damages in conjunction with the furnishing performance or use of this material All product specifications as well as the information contained in this publication are subject to change without notice This publication may contain or reference information and products protected by copyrights or patents and does not convey any license under the patent rights of Bruker AXS Inc nor the rights of others Bruker AXS Inc does not assume any liabilities arising out of any infringements of patents or other rights of third parties Bruker AXS Inc makes no warranty of any kind with regard to this material including but not limited to the implied warr
97. Parameters 00 cee ee 12 4 12 3 Mapping Software Features 000 cece tees 12 7 13 Nomenclature and Glossary 00 cece eee eee 13 1 13 1 Nomenclature 5 2 ome Ee b pale Pe oth O ate hte G4 ub Pete aot id nd 13 1 13 2 Glossary orta ETE 13 5 13 3 Glossary of Software Terms 000 ccc re 13 12 M86 E01007 1 05 v Table of Contents GADDS User Manual vi M86 E01007 1 05 GADDS User Manual Introduction and Overview 1 Introduction and Overview 1 1 Introduction GADDS General Area Detector Diffraction Sys tem introduced by Bruker AXS Inc is the most advanced X ray diffraction system in the world The core of GADDS is the high performance two dimensional 2D detector the Bruker AXS HI STAR area detector The HI STAR is the most sensitive area detector a true photon counter with a large area The speed of data col lection with an area detector can be 10 times faster than with a point detector and about 100 times faster than with a linear position sensitive detector Most importantly the data has a large dynamic range and 2D diffraction information Compared to 1D diffraction profiles measured with a conventional diffraction system a 2D image collected with GADDS contains far more information for various applications By introduc tion of the innovative two dimensional X ray dif fraction XRD theory GADDS has opened a new dimension in X ray powder diffraction Phase ide
98. S is shown as a reference in Figure 9 6 The frame is in the magnification of 2x The chi integration profile in the chi range of 75 105 q 1 n gt vhs I n t e n s i t y A N 5j Li RIX 2 theta in degrees Figure 9 6 The SAXS frame collected with NanoStar magnified by 2x on rat tail tendon The chi integrated profile in the chi range of 75 105 and two theta range of 0 2 2 shows the second to above ninth order peaks chi integration box and two theta range of 0 2 2 shows the sec ond to above ninth order peaks of SAXS pattern from the rat tail tendon sample The scattering vector length q nm is also marked above the profile plot For Cu Ka radiation the relation between q and 20 is q nm 20 71x20 9 9 M86 E01007 Small Angle X ray Scattering GADDS User Manual The data frame collected with He beam path Figure 9 7 shows some parasitic scattering in the left of the beam stop but most regions around the pinhole are free from parasitic scat tering Figure 9 8 shows the same frame in 8x magnification The conic cursor marked the most achievable resolution which is about 250A equivalent to 0 35 in two theta and 0 25 nm 1 in scattering vector length q This is Figure 9 7 Data frame collected from rat tail tendon with He beam path maximum resolution with 30 cm He beam path 0 1 mm pinhole collimator 4 mm beam stop and Cu tube Figure 9 9 shows the da
99. SS software for stress anal ysis 12 08 97 Created Mag Quad Omega Width Counts Time s Distance Size 2th begi 2th en chi begi chi en it n t e ri S i t y Distance 0 FloodFld 2 theta in degrees Spatial Figure 6 24 A measured frame with chi integrated profile The green broken line box defines the chi integration region The blue broken lines indicate the shadow of the wires 1024x1024 frames SMsprg3u 006 11 42 00 12 08 97 1 0 147 00 0000 40790 120 00 15 000 1024 150 00 160 50 80 000 100 00 15 000 1024 015 1024 015 No PDC Fee FPF HEP NN MN M86 E01007 6 29 Residual Stress GADDS User Manual The results are listed in Table 6 3 The y tilt is achieved by iso inclination Q scan The resid ual stress values determined in scans of 7 and 19 steps agree very well The 19 points mea surement has a lower standard deviation about 3 5 Table 6 3 Residual stress measurement results of the inside surface of a stainless steel spring Number of frames 7 19 vy angles and steps 45 to 45 15 steps 45 to 45 5 steps Data collection time 14 minutes 38 minutes Measured stress 864 48 MPa 875 31 MPa d vs sin y plot Lattice Spacing in 10 10m 0 0 1 02 03 sin 2 Psi Lattice Spacing in 10 10m 0 0 1 0 2 0 3 0 4 05 sin 2 Psi 6 30 M86 E01007 GADDS User Manual Residual Stress
100. TRUE DO LOAD F gfrm USE CONFIG SAVE F gfrm DISPLAY NEXT INC F WEND To execute you would enter UpdateSamples Example For a sample you wish to add with the scan time dependant on the current 2T angle The first script MyAdd slm would look like IF 1 lt 0 0 THEN LET T 10 00 00 ELSEIF 1 0 0 THEN LET T 1 00 00 ELSEIF 1 gt 0 0 THEN LET T 10 00 00 END ADD T 10 28 M86 E01007 GADDS User Manual Automation 11 Automation Automation involves instrument operation with minimal or no user interaction to perform sample control 24 7 operation quality control or an audit trail To minimize user interaction you must first determine how each sample is handled on the instrument What varies between samples and what stays the same For sample control how are multiple samples mounted on the instru ment For 24 7 operation samples must be removed and replaced with the next samples usually by robotics Also the information for the new samples must be fed to the instrument Quality control and audit trail are side effects of automation By automating procedures and recording changes and steps i e an audit trail you can achieve consistent results and prove that you followed standard operating procedures SOP Automation is best implemented in phases Phase 1 Primitive automation Phase 2 Optimize automation Phase 3 Sample handling Phase
101. The cross section shows the beam stop and adjustment micrometer M86 E01007 GADDS User Manual System Configuration 2 7 Standard GADDS Systems A GADDS system can be built with the typical components introduced in the previous sections and many special components in various config urations for different applications Due to the modular design concept of the D8 DISCOVER GADDS systems have the compatibility and the flexibility to switch quickly and easily between different configurations and options Based on the majority of application requirements we have five standard GADDS systems in horizon tal configuration Standard Basic Fixed Chi System Figure 2 16 Standard Microdiffraction System Figure 2 17 Standard Stress Texture System Figure 2 18 Standard Huber Eulerian Cradle System Figure 2 19 and Standard Centric Eulerian 4 Cradle System Figure 2 20 M86 E01007 System Configuration GADDS User Manual Figure 2 16 Standard Basic Fixed Chi System 2 38 M86 E01007 System Configuration GADDS User Manual Figure 2 17 Standard Microdiffraction System M86 E01007 System Configuration GADDS User Manual Figure 2 18 Standard Stress Texture System 2 40 M86 E01007 GADDS User Manual System Configuration Figure 2 19 Standard Huber Eulerian 4 Cradle System M86 E01007 2 41 System Configuration GADDS
102. age over a range defined by beam size in the Z direction Since the diffraction data outside of the diffracto meter plane is not detected the material struc ture represented by the missing diffraction data will either be ignored or extra sample rotation and time are needed to complete the measure ment forward jd AMEN detection circle backward diffraction Figure 1 3 Diffraction patterns in 3D space from a powder sample and the diffractometer plane With a two dimensional detector the diffraction is no longer limited to the diffractometer plane Depending on the detector size distance to the sample and detector position the whole or a large portion of the diffraction rings can be mea sured simultaneously Figure 1 4 shows the dif fraction pattern on a two dimensional detector compared with the diffraction measurement range of a scintillation detector and PSD Since the diffraction rings are measured the variations of diffraction intensity in all directions are equally important and the ideal shape of the X ray beam cross section for XRD is a point point focus In practice the beam cross section can be either round or square in limited size M86 E01007 GADDS User Manual Introduction and Overview scintillation detector small spot measured W scan necessary long measuring time large 20 range measured simultaneously m medium measuring time m large 20 and c
103. alled Debye ring Diffractometer An instrument for measuring diffraction effects specifically for measuring the direc tions and intensities of diffracted beams from crystals Diffractometer Plane A plane defined by the laboratory axes X and Y In the conventional diffractometer with a point detector or linear PSD the dif fraction data is collected by scanning within the plane In a two dimensional diffraction system the detector center moves within this plane Divergence The angle between two extreme rays in an divergent X ray beam Face Centered Cubic A crystal structure found in some metals Within the cubic unit cell atoms are located at all corners and face centered positions Fiber Any polymer metal or ceramic that has been drawn into a long and thin filament Flood Field Correction A procedure to create a spatial mapping for the multiwire detector from exposure to a uniform spherically radiating point source The flood field correction does not alter the number of photons counted and reported It simply applies a spatial rubber sheet stretching and shrinking of reported posi tions so that the frame collected from a uni form source appears uniform M86 E01007 Nomenclature and Glossary GADDS User Manual Focal Spot On Target In a sealed tube or a rotating anode genera tor the area on the anode bombarded by electrons is called focal spot on target Depending on the size o
104. also called rolling direction RD or fiber axes for wires fibers Keep in mind that the reciprocal and direct real space crystallographic direc tions are only coincident in cubic systems Other conventions will be noted here for refer ence Metallurgists typically define a either iden tical to GADDS definition or as the angle from sample normal to diffraction vector which is a 90 a Beta is defined starting at RD which is p B 90 Polymerists define y chi instead of a as either y a or y 90 a Phi is used instead of Beta As Bruker AXS uses and y for diffractometer angles we will use a and p for pole figures for less confusion M86 E01007 Texture GADDS User Manual In Figure 5 2 the upper left quadrant shows measured reflections of multiple discrete grains in an inorganic thin film The upper right plot shows the 20 values for each of the lines The lower right plot a 2theta integration proves the existence of texture in the thin film and the lower left shows the final pole figure for the film Notice again that several hkl lines are col lected on the area detector simultaneously As long as corrections are made for sample absorption and polarization it is possible to col lect data for several hkl lines and thus several pole figures simultaneously which greatly reduces data collection time 10 20 30 40 50 60 70 Degrees 100 Degrees Figure 5 2 Raw data to p
105. an type can be easily modified depending on the user application and system configuration i e detector distance Example 11 1 Automatic handling of a library File 96wells slm Collect targets in a 96 well library Assumes GADDS CS system Assumes distance cm runbase 36 runchar 3 or this will fail Assumes Target list already defined by the grid targets command with run numbers A01 to H12 List of variables that are inserted into the script file before every measurement 1 jobname base of filename 2 scan time 1 00 minutes or seconds 3 title SFILE filename 4 sample name plate id 5 sample number barcode first collect all frames on all targets on error then continue scan multitargets 2 thetal 10 amp theta2 10 1 scantime 2 axis C amp width 20 title 3 sample 4 amp numsample 5 clear startrun 1 amp endrun 9999 mode step Integrate all frames on error then continue Targets A01 to A12 let SR A01 while SR lt A12 do 11 2 M86 E01007 GADDS User Manual Automation gadds scripts 96WellsSub inc R wend Targets B01 to B12 let R BO1 while SR lt B12 do gadds scripts 96WellsSub inc R wend Targets C01 to C12 let R C01 while SR lt C12 do gadds scripts 96WellsSub inc R wend Targets D01 to D12 let R DOL while SR lt D12 do gadd
106. and y NOTE The video camera has a zoom function that is supported in manual mode Adjust the sample height until the laser spot appears in the crosshair P right sample position sample laser spot at cross hair of video image represents the measured spot on sample Figure 3 12 Adjust sample height Transmission mode Ensure that the beam stop is attached to the collimator Drive omega to 30 Adjust the sample holder x and y coordinates so that the sam ple is centered in the crosshair Ensure that for the angles phi 0 90 180 and 270 the sample is centered in the crosshair For flat samples do not drive phi Align to the sur face Do not rotate M86 E01007 GADDS User Manual Basic System Operation For the Huber Centric cradle do not drive omega to 30 because the collision limit is 20 For flat thin samples e g polymer films pow der etc on a quarter cradle with phi equal to 0 drive omega to 0 Mount the sample In manual mode turn the camera and laser on Adjust the position of the sample with y and z Use x to bring the laser spot into the center of the crosshair When using a capillary on a cradle check the rotation of the sample after performing the steps above NOTE Generally in transmission mode the plain normal to the optical axis containing the geometrical sample center can be adjusted in focus at omega 55 At omega 30 the opti cal axis is parallel t
107. anipulation and interpretation Because of the unique nature of the data col lected with a 2D detector a completely new concept and new approach are necessary to configure the XRD system and to understand and analyze the 2D diffraction data In addition the new theory should also be consistent with M86 E01007 Introduction and Overview GADDS User Manual the conventional theory so that the 2D data can be used for conventional applications First we compare conventional X ray diffraction XRD and two dimensional X ray diffraction XRD Figure 1 3 is a schematic of X ray dif fraction from a powder polycrystalline sample For simplicity it shows only two diffraction cones one represents forward diffraction 20 lt 90 and one backward diffraction 20 gt 90 The diffraction measurement in the conventional diffractometer is confined within a plane here referred to as the diffractometer plane A point detector makes a 20 scan along a detection cir cle If a one dimensional position sensitive detector PSD is used in the diffractometer it is mounted along the detection circle i e diffrac tion plane Since the variation of the diffraction pattern in the direction Z perpendicular to the diffractometer plane is not considered in the conventional diffractometer the X ray beam is normally extended in the Z direction line focus The actual diffraction pattern measured by a conventional diffractometer is an aver
108. anties of merchantability and fitness for a particular purpose No part of this publication may be stored in a retrieval system transmitted or reproduced in any way including but not limited to photocopy photography magnetic or other record without prior written permission of Bruker AXS Inc Address comments to Technical Publications Department Bruker AXS Inc 5465 East Cheryl Parkway Madison Wisconsin 53711 5373 USA All trademarks and registered trademarks are the sole property of their respective owners Revision Date Changes 0 10 99 Original release 1 1 05 Added Sections 11 and 12 Revised Sections 1 2 3 5 6 7 and 10 ii M86 E01007 1 05 GADDS User Manual Table of Contents Table of Contents NONGO doen vex adu te betae Robes iea eee tacba a atouts ard esta Alta aie fet Seale ii 1 Introduction and Overview slsleeeleeeeeeeeeeeeeeere 1 1 LR eroi EE m 1 1 1 2 Theory of X ray Diffraction Using Area Detectors 0 eee eee 1 4 1 2 1 X ray Powder Diffraction 0 0 eee 1 4 1 2 2 Two Dimensional X ray Powder Diffraction XRD nr RC 1 5 1 8 Geometry Conventions llslsllllelsele hrs 1 8 1 3 1 Diffraction Cones and Conic Sections on 2D Detectors 0000 0 eee 1 8 1 3 2 Diffraction Cones and Laboratory Axes 0 000 cece eee 1 9 1 3 3 Sample Orientation and Position in the Laboratory System lsuuu 1 10 1 3 4 Detect
109. as always been a slow process due to limited beam intensity diffi culty in sample positioning and slow point detectors In the GADDS microdiffraction sys tem we have solutions for all of these problems The cross coupled G bel mirrors and the Mono Cap optics can deliver high intensity beams The laser video sample alignment system can accurately align the intended measurement spot of a sample to the instrument center where the X ray beam hits The motorized XYZ stage can move the measurement spot to the instrument center and map many sample spots automati cally The 2D detector captures the whole or a large portion of the diffraction rings so that spotty textured or weak diffraction data can be integrated over the selected diffraction rings Thin film samples with a mixture of single crys tal random polycrystalline layers and highly tex tured layers can be measured with all the features appearing simultaneously in diffraction frames Stress and texture can be measured quickly or even simultaneously with the new stress and texture approach developed for M86 E01007 GADDS User Manual Introduction and Overview XRD The texture can be displayed as a pole figure or fiber plot The weak and spotty diffrac tion pattern can be compensated by integration over the 2D diffraction pattern M86 E01007 Introduction and Overview GADDS User Manual 1 2 Theory of X ray Diffraction Using Area Detectors 1 2
110. asitic scattering If the scatter 0 10 0 08 0 143 0 15 599 231 ing signal from the sample is much stronger 0 20 016 0286 026 344 231 than the parasitic scattering or if the halo is 0 30 023 10418 10 34 257 281 evenly distributed around the beam stop the ee 0 50 0 27 0 639 0 43 207 231 parasitic scattering will not limit the achievable resolution Some efforts are necessary to G bel Mirrors reduce the parasitic scattering such as using 0 05 0 04 0 071 0 09 951 231 high parallel beam G bel mirrors smaller pin 0 10 0 06 0 131 0 12 716 231 hole size and appropriate pinhole combination 0 20 0 00 0231 0 14 620 231 Table 9 1 lists the beam divergence o4 the pri 0 30 0 00 0331 10 16 546 231 mary beam stop on the sample D the maxi 0 50 0 06 10531 1020 442 231 mum angular resolution ama the resolution R and the resolution limit of beam stop Fipg for various collimator sizes 0 05 mm to 0 5 mm at a sample to detector distance of 300 mm It can be seen that the beam stop determines the achievable resolution for most cases 9 4 M86 E01007 GADDS User Manual Small Angle X ray Scattering 9 2 Data Collection and Analysis 9 2 1 SAXS Attachments Installation Figure 9 2 shows the beam stop assembly attached to the HI STAR detector Figure 9 2 Small angle scattering beam stop attached to HI STAR detector Figure 9 3 shows the Helium b
111. ated back to the parent script or program HLET C A B LET C A B LET C A B LET C A B Define the value for a string variable using simple math Only a single operator _ or is allowed A and B can be variables or constants INC A INC base A INC16 A INC36 A Increment a string variable using the speci fied base Base must be between 2 and 36 If missing the base defaults to 10 ON ERROR THEN CONTINUE ON ERROR THEN NEXT ON ERROR THEN BREAK ON ERROR THEN STOP ON ERROR THEN EXIT Define how to handle error conditions After an error occurs you may e continue to process the next line in the script file e next iteration of a WHILE block e break out of a WHILE block then continue e Stop processing the current script e exit all scripting When nesting script files the on error value is inherited from the parent script or program New on error value is not propa gated back to the parent script or program Default is EXIT Outside of a WHILE block M86 E01007 10 25 Script Files GADDS User Manual BREAK is equivalent to STOP Errors in any flow control statement always generate at least a STOP CONTINUE and BREAK are treated as STOP IF conditional THEN ELSEIF conditional THEN optional Multiple ELSEIF s are allowed ELSE optional ENDIF Define blocks of commands that are condi tionally executed When the cond
112. atial 1024_015 1024x1024 Cu Bias love detector w mouse ENTER L button quit ESC O buttons restore C Center Figure 3 11 Adjust the rings 6 If you are the Instrument Administrator press Enter to update the current configura tion M86 E01007 3 17 Basic System Operation GADDS User Manual 3 6 Sample Positioning 3 6 1 XYZ Stage The sample positioning procedure makes sure that either the surface of a sample for reflection measurements or the geometrical center of the sample for transmissions mode is in the center of the diffractometer For this procedure you need either the video microscope or the laser video alignment system 1 Mount the sample to the sample stage Ensure that the major sample axes are par allel to the major axes of the sample mount and to the major axes of the sample stage e g an orthorhombic sample is mounted with its x y and z axes parallel to the x y and z axes of the xyz stage or of a stan dard goniometer head NOTE Ensure that the beam stop is attached to the collimator if you are going to measure in transmission mode or at 2 theta and omega angles below 2 2 Reflection mode optical microscope Drive omega to 0 and adjust the sample height until the focus line of the microscope is in the microscope crosshair Reflection mode laser video sample alignment system Drive 2 theta to 55 Use the video camera crosshair and laser spot to align the sample in x
113. ations Examples 00 RII n 9 15 9 9 T4 RBieferences ive p Ee Ea eh ee Bald wee aw eek as 9 16 10 Script Piles iiir cee oink ohana x re E Ae seem ES ees 10 1 10 1 SLAM Command Conventions 0 000 cece tees 10 2 10 2 Executing Script Files c Ms oe eid he wo ai Granth bana EMI oe RUN RUE RR es 10 5 iv M86 E01007 1 05 GADDS User Manual Table of Contents 10 3 Creating Script Files eux DREAM e xp a date eens eas TN ERES 10 7 10 4 Using Replaceable Parameters within Script Files 00000 0c ee eaeeae 10 16 10 5 Adding Script Files to the Menu Bar as User Tasks 00 00 cece eee eee 10 21 10 6 Nesting Script Filess tnb ret ig ve Mou as i eae meia pute depre qe 10 23 10 7 Flow Control Inside Script Files 0 0 00 ccs 10 25 11 Automation hacer racc ixa cc eR ERE psa duda EVER Y RESREYE 11 1 11 1 Primitive Automation osas saneras eta a a m ara 11 2 11 2 Optimize Automation minine r raaa a na ene ane eee REC ee eee AERE 11 4 11 3 Sample Handling esaia e aa eru E ele ote dae ho Yo aed cee ph es 11 6 11 4 Remote Control 0 0 0 0 06 eee 11 7 11 5 Audit Trails 24 iiber ER oi oa aa Peg eG EE Rede EE E 11 8 12 MapDIDQg weirs uci ee ce wen eos Roe kee ne eee RS ee ue 12 1 12 1 Procedure Demo Data ssssleeeeeee nen 12 2 12 2 Procedure Real Data 0 ccc re 12 4 12 2 1 Frames to Process i e ce ew ehe Shee eee Gale ee eae ea 12 4 12 2 2 Processing
114. ave different degrees of orientation texture Figure 1 9 Al TiN film on Si Specimen was rotated in 6 Note that the Al and TiN have the same 111 orientation and both have fiber texture The Al and TiN are highly oriented polycrystalline materials while the Si substrate is single crystal The stack is roughly 0 5 um thick Figure 1 10 Nylon 6 fiber with an inorganic filler Two distinct orthogonal orientations are visible The faint continuous rings are from the polycrystalline inorganic filler M86 E01007 Introduction and Overview GADDS User Manual Figure 1 11 Flexible TAB Tape Automated Bonding material The two phases are gold and copper The smooth and continuous rings are the fine grained gold The spotty rings belong to large grained copper The small divisions on the crosshair are 20 um When integrating an area detector frame in the x direction a standard powder pattern inten sity versus 20 diagram is obtained The added benefit of the area detector is that the intensities so obtained take preferred orientation into account This is a tremendous advantage when performing phase analysis on oriented materials such as clay minerals Area detector frames may also be processed to obtain texture infor mation in the form of pole figures fiber texture plots and orientation indices The coverage of the area detector frequently enables multiple poles with backgrounds to be collected simulta neousl
115. ay to your liking An example from the demo data is shown in the fol lowing figures Ani x 33 0 91 1 83 2 75 3 67 4 535 51 5 435 35 7 27 8 13 9 12 0 Print Figure 12 6 Default Settings M86 E01007 Mapping GADDS User Manual AdvilMap gmap 980 900 81 0 72 0 530 540 LE 450 LIE 36 0 27 0 18 0 80 Cancel Print Anl x N GO 4 CT OD 4 CO CO SCWOONOOE WN O coooooooooo Figure 12 7 Customized Settings 12 8 M86 E01007 GADDS User Manual Nomenclature and Glossary 13 Nomenclature and Glossary The nomenclature and glossary used in this manual are frequently referred by textbooks and literature and commonly accepted in the X ray diffraction field To avoid confusing you with a variety of different definitions of symbols and technical terms some of the symbols technical terms and abbreviations used in this manual are listed in the following sections The symbols and terms having no ambiguity may not be included in the list 13 1 Nomenclature a The detector swing angle to define the angle between detector center to the laboratory axis X alternatively 20p 2 Theta in GADDS software a The maximum angle of convergence a The takeoff angle the angle between exit beam and anode surface in the X ray tube a The angle defining the pole direction of a reflecting plane relative to a sample plane The stereographic projection
116. ble for reliable calibra tion of the sample to detector distance and beam center You can use either method Use manuals 269 023301 Detector Distance and Beam Center Calibration for GADDS and 269 02200 GADDS Application Test for instructions on one method or use the following 1 Mount corundum standard plate to the sam ple stage either as a flat sample for reflec Options for Collect Scan SingleRun x a Frames 1 Seconds frame 90 2 Theta 40 deg Omega 20 deg Phi 0 000 deg Xx 0 314 mm Y 0 000 mm z o 549 mm Scan Axis None Frame width 0 0 Mode STEP I Rotate sample Sample Osc xv x Amplitude fi mm Frame header information Tile Corundum C O OOOOOO Sample name Corundum Sample number MF tion measurements or in a capillary for transmission measurements See Sample Positioning for mounting details 2 Left click Collect gt Scan gt SingleRun and collect one or several frames at detector swing angles within the 2 theta range you need to calibrate See Data Collection for details on performing this step If using a corundum plate XY sample oscillations may improve the quality of the scan Chi 90 000 deg Aux 7 000 mm v Filename generation Job name Corundum 500um Run foo First filename Corundum 500um_0 0 001 gfrm Frame 1t oo1 Max display counts iv Realtime display Iv Pre clear Capture video image Auto Z Align Figur
117. broadening standard with a Cauchy FWHM of 0 133 the corrected FWHM is 0 167 and the Scherrer equation gives a crystallite size of 512 A 47 231 p Ww rrt ua2mmt2H 16 8 2 theta in degrees 33 5 Figure 7 3 Graphite coated beads Profile fitting the graphite peak with a split Cauchy gives a peak location of 25 705 20 and a FWHM of 2 748 Using LaBg as an instrumental broadening standard with a Cauchy FWHM of 0 133 the corrected FWHM is 2 615 and the Scherrer equation gives a crystallite size of 32 A Note that to ensure proper fitting of the graphite peak the substrate peak was also fit with a Gaussian profile M86 E01007 Crystal Size GADDS User Manual 7 3 Microstrain Broadening Peak broadening due to microstrain can also be determined This technique usually involves analysis of the peak profile shape from which contributions due to crystallite size and micros train are separated Microstrain in materials increases the line width as a function of 20 The deconvolution of the width from crystallite size and lattice distortion is based on the Warren Averbach method This method involves the measurement of the complete profile of multiple orders of the same reflection e g 100 200 300 In summary the peak profiles of the standard and unknown are deconvolved into Fourier coefficients that are corrected for instru mental broadening Plotting the Fourier coeffi cients as a function of
118. cally reliable corrections can be made This frame is subtracted from the original frame using FILE LOAD with the SCALE n qualifier which scales the background frame to the time of the data frame If there is significant absorp tion in the polymer sample the background frame should be scaled so that the parasitic scattering around the beam stop is reduced to near zero For 0 3 mm or larger collimators the 6 beam stop should be used Otherwise use the 4 beam stop M86 E01007 Texture GADDS User Manual 5 9 Fiber Orientation nss Figure 5 8 Wire fiber holder attached to an SEM specimen mount The dashed line is a fiber For orientation work the fiber should be mounted on a wire frame These frames are readily made from paper clips The length of the fiber should be no longer than 2 cm and the dis tance from the fiber to the back portion of the frame should be no longer than 1 5 cm The goniometer head used for mounting fibers should be of the eucentric type This allows fine adjustment of the physical fiber axis with respect to the goniometer axis The fiber frame can be affixed with wax or clay to an aluminum SEM specimen holder available from electron microscopy supply houses which mounts in the goniometer head The wax should have good adhesion properties at temperatures up to 40 C and should not undergo elastic relaxation The physical fiber axis should be aligned vertically either using the two positio
119. ces 0 000 cece eee 5 23 5 15 Fiber Texture Plots i vi adie s we Rak EG we EDA ee ae aa Pee De ee ake 5 25 5 16 References gave ears deu SAB Ee ane a eh BPR we Re ac RP ee aS 5 29 6 Residual Stress voz eek eke FEY dipsa bad e exe saa REPE Yd 6 1 6 1 Principle of Stress Measurement 00 00 cette eee 6 1 6 1 1 Theory of Conventional Method ssssssesese ren 6 1 6 1 2 Theory and Algorithm of 2D Method 0 cee ee 6 3 6 1 3 Relationship Between Conventional Theory and 2D Theory suse 6 7 6 1 4 Advantages of Using 2D Detectors 0 0 ee 6 9 6 16 Parametersc z ool Pew RE ee Ree ne Game dy Shad dpe c PG EMI Oe RO rv a 6 12 6 1 6 GADDS System Requirements 0 00 c eee 6 15 6 1 7 Data Collection Strategy 0 0 60 cae 6 16 6 1 8 Data Collection Procedures 0 00 c cette 6 18 6 2 Stress Evaluation Using One Dimensional Data Conventional Method 6 19 6 3 Stress Evaluation Using Two Dimensional Data 2D Method 00 5 6 22 6 4 Application Examples aA a A E D EE A A E a A 6 28 6 4 1 Example 1 Conventional Method Residual Stress Measurement with GADDS Microdiffraction System 0 00000 cette 6 28 M86 E01007 1 05 iii Table of Contents GADDS User Manual 6 4 2 Example 2 2D Method Comparison Between 2D Method and Conventional Method 6 31 6 4 3 Example 3 Stress Mapping with 2D Method s ses
120. copper or molyb denum with fast electrons The spectrum of the emitted radiation has a maximum inten sity at a few wavelengths characteristic of the target material M86 E01007 13 11 Nomenclature and Glossary GADDS User Manual XRD Two dimensional X ray diffraction system alternatively 2DXRD 13 3 Glossary of Software Terms Arguments Within script files arguments are parame ters valued qualifiers or non valued qualifi ers ASCII A file that consists of pure text characters no formatting codes Batch mode Non interactive processing of data typically done using scripts Command Within script files a command consists of a verb sub command and arguments Command mode Program mode where commands are type on the command prompt line Macro See script Menu Mode Program mode where commands are invoked from the menu bar and dialog boxes Nesting Calling one script file from within another script file is called nesting 13 12 M86 E01007 GADDS User Manual Nomenclature and Glossary Parameters Within script files parameters are argu ments for the command Typically these are required arguments Qualifier Within script files qualifiers are arguments for the command Typically these are non required arguments and can be either val ued or non valued qualifiers Replaceable Parameters Within script files the variables 1 to 0 are used as placehol
121. cross contamination between adjacent samples Figure 2 25 Transmission diffraction system for combinatorial screening M86 E01007 2 51 System Configuration GADDS User Manual 2 8 8 Sample Stage and Screening Grid The XYZ stage has a travel range of 100 mm 150 for transmission x 100 or 150 mm x 100 mm and a maximum loading capacity of 10 kg 5 kg for transmission with a 12 5 um position accuracy and a 5 um repeatability The instru ment center is defined by the cross point of the incident X ray beam and the center line of the detector The system automatically and sequen tially puts each cell in the material library into the instrument center based on the predetermined XYZ grid points The system can also generate an XYZ grid file by inputting the X Y coordinates of the starting point and end point and the sepa ration step between each grid point see Fig ure 2 26 2 52 M86 E01007 System Configuration GADDS User Manual End point X step POD OGDOO OY SGOOOGHOE 6000600006 OO OOOO O 6060600006 0 80 0 0 09 00 00 099 Starting point Figure 2 26 The grid points are determined by the starting Y step and ending points and steps M86 E01007 System Configuration GADDS User Manual 2 8 4 Retractable Knife Edge A motorized retractable knife can be used for reflection mode screening at low Bragg angle range to improve the resolution reduce the air scatt
122. ctor center to the laboratory axis X alternatively a 2 Theta in GADDS software The Bragg angle of the monochroma tor crystal The X ray wavelength The stress tensor with six components O11 O12 O22 O 13 O23 933 The left handed sample rotation angle about its surface normal or axis The axis is always perpendicular to x or v axis and the angle between the axis and o axis is xs The azimuthal angle about X defining the direction of the diffracted beams on the diffraction cone y starts at 6 o clock direction with right handed rotation axis in the opposite direction of X It is also called the diffraction cone x angle to distinguish from the instrument xg Chi in GADDS software The lower x boundary of 20 or x inte gration range chi begi in GADDS soft ware M86 E01007 GADDS User Manual Nomenclature and Glossary X2 Xg The higher y boundary of 20 or y integration range chi end in GADDS software The sample rotation angle about a rota tion axis within the X Y plane When 0 0 The xg is a left handed rotation with the axis on X and sample surface normal on Z at xg 0 The symbol x may be used to refer to this angle some times Chi in GADDS software The sample rotation with the same rota tion axis as x except different starting point x g 90 y The tilt angle between the sample sur face normal and the diffraction vector y tilt is use
123. cture with multiple orientations Polycrystalline materials could also be multiphase materials with more than one kind of crystal blended together Poly crystalline materials can also be bonded to dif ferent materials such as semiconductor thin films on single crystal substrates The crystalline domains could be embedded in an amorphous matrix or stressed from a forming operation Usually the sample undergoing X ray analysis has a combination of these effects Polycrystal line diffraction deals with this range of scattering to determine the constituent phases in a mate rial or the effect of processing conditions on the crystallite structure and distribution The myriad properties that can be measured with X rays are related to material purity strength durability electrical conductivity coefficient of expansion and so forth Analyses commonly performed on polycrystal line materials with X rays include Phase identification Quantitative phase analysis Texture orientation Residual stress Crystallite size Percent crystallinity Lattice dimensions Structure refinement Rietveld 1 2 2 Two Dimensional X ray Powder Diffraction XRD Two dimensional X ray diffraction 2DXRD or XRD is a new technique in the field of X ray diffraction XRD XRD is not simply a diffracto meter with a two dimensional 2D detector In addition to 2D detector technology XRD involves 2D image processing and 2D diffraction pattern m
124. d sample properties It differs for powders single crystals and textured materials For details see Blake 1933 and the Interna tional Tables 1967 Presently no Lorentz correction is implemented in GADDS The polarization correction depends on the inci dent beam optics e g Kp filter monochro mator G bel Mirrors If fiber or plate absorption corrections are desired it is faster to apply them as options of POLE FIGURE PROCESS rather than applying the CORRECTION command to the entire series of frames Use POLE FIGURE PROCESS to integrate the reflection of interest in each of the frames Typically 72 frames are collected 5 steps in gt and all frames are processed in sequence from 001 through 072 unless a frame number is manually changed to break the sequence M86 E01007 Texture GADDS User Manual For accurate ODF and percent random analysis background must be removed see figure 5 4 For unfamiliar systems the integration should be monitored to spot potential problems For example if a substrate reflection occurs in a background region the integrated area will be negative A status line on the bottom of the screen will indicate the number of pixels that were negative and the magnitude of the largest The remedy is to select a background away from the interfering intensity The background removal model in GADDS is linear If the mate rial has amorphous content background should not be removed
125. d for stress measurement in the conventional diffractometer The right handed rotation of the sample about Z When xg 90 and w 0 the sample surface normal is on Y_ o is also the angle between X and x axis Omega in GADDS software The anisotropic factor used in stress calculation The detector distance from the instru ment center also called sample to detector distance Res S4 The distance between two adjacent crystal planes also called d spacing The d spacing of a specific crystalline plane with index hkh The pinhole diameter in the collimator The unstressed d spacing normally used for stress measurement to repre sent d value without stress The strain coefficient used for strain measurement with six components f 7 fia foo 13 fo3 f33 The stress coefficient used for stress measurement with six components P11 P12 P22 P13 P23 P33 The modulus of the scattering vector most frequently used in the small angle scattering The resolution of a SAXS system defined as the theoretically largest resolvable Bragg spacing The resolution of limit of the beam stop of a SAXS system One of the macroscopic elastic con stants used for stress measurement also expressed as S hkl if the aniso tropic correction for a specific crystal line plane is considered M86 E01007 Nomenclature and Glossary GADDS User Manual 4 94 S2 One of the macroscopic elastic co
126. d the following window will appear xi Exit Load Baseline Zoom Simulate Profile Auto Manual Refine Save View Clear PDF2 Per_crystal Figure 12 4 Peaks window 6 Select Profile and then select Add xj Exit Add Delete Figure 12 5 Profile window 7 Select OK 8 Change values using 1 2 3 and 4 while moving the mouse Values 1 and 2 corre spond to the background region at low 20 while 3 and 4 represent the background region at high 20 9 Select Exit r 10 In the command line type MENU and hit return GADDS gt MENU 11 Repeat the procedure for mapping from the beginning to achieve the mapping result M86 E01007 GADDS User Manual Mapping 12 3 Mapping Software Features Once you have an active mapping array dis played there are several features within the pro gram that allow you to customize the display The first of these is in the drop down menus of the program itself Select the view menu to change the display of the map to see circular samples label values and even utilize a pass fail functionality for each data point Double click AdvilMap gmap Cancel on the intensity scale to change the color dis play and scale as well as the brightness and contrast In addition to these display changes right click on the map and select 3D plot to get a 3D image of the map Right clicking on the 3D map opens a separate window that allows you to customize the 3D displ
127. ddsnew merge b S1 2 raw S1 2 merge raw Note If the scan parameters are changed the integration range 2theta start end Chi start end also needs to be changed to the correct values 11 2 Optimize Automation In section 11 1 we automated our phase identifi cation on a single library of wells In this section our goal is to handle many plates as quickly as possible To do this we need to identify bottle necks and minimize efforts Bottlenecks to this process are the manual load ing of plates and sample information data acquisition i e two frames on each sample and data processing Data processing is faster than data acquisition so we can process the last library while we re collecting the next library Each well has different amounts of samples Some samples are amorphous and do not dif fract By identifying non diffracting samples early and then skipping those samples we mini mize effort For diffracting samples we identify the minimum data acquisition time The result is the most time efficient means of collecting data Let us say from experimentation with our sam ples we ve determined that frames below 1000 cps are too weakly diffracting for our purposes but frames with 250 000 total counts will pro cess and produce acceptable results We mod ify our previous script to perform a one second pre scan at the low 2 theta detector position and use frame header variables with flow control t
128. ders for text strings passed on the command line Script The ability to execute a series of commands as a single task is called scripting SLAM Scripting Lexical Analyzer Monitor which is the syntax for commands within script files Spawn Starting another program from within your current program Both programs are execut ing independently Spawn and Wait Starting another program from within your current program but only the new program is executing The original program is sus pended until the spawned program termi nates Subcommand Within script files the subcommand of the major grouping of commands such as DIS PLAY NEW Subroutine See nesting User task A script added to the menu bar is called a user task Variables Within script files the variables 9 1 to 98 can be used to denote the current value of the axes 20 to zoom Verb Within script files the verb is the command or major grouping of commands such as DISPLAY M86 E01007 13 13 Nomenclature and Glossary GADDS User Manual 13 14 M86 E01007
129. diffracted by the crys tal is given by the Bragg law 1 22dsinOy We can set the monochromator crystal to a diffrac tion condition such that only the wavelength of Ka1 satisfies the Bragg law X rays of other wavelengths are filtered out by the monochro mator As shown the X rays must also be in the correct direction to satisfy the diffraction condi tion Thus the reflected beam from a monochro mator with a perfect crystal will be a parallel X ray beam 20m knife edge ano e Figure 2 5 Illustration of a crystal monochromator Monochromatic X rays are obtained by diffraction from a single crystal plate In practice the reflected beam from a mono chromator is not strictly monochromatic due to the mosaic of the crystal measured by rocking angle The crystal type in a monochromator must be chosen based on the performance you require in terms of intensity and resolution Crystals such as Si Ge and quartz have small rocking angles accompanied by high resolution and low intensity while graphite and LiF crystals have high intensity and low resolution due to large mosaic spreads The monochromator crystal shape also varies from flat to bent to cut to curve A flat crystal is used for parallel beams and a curved crystal is used for focus geometry The standard GADDS system uses the flat graphite monochromator which gives the stron gest beam intensity The monochromator is designed to accept a limited angular range of
130. directions such as sample normal ND and machine or rolling direction RD For wires and fibers the sample axis direction is used for RD Typically one to four independent reflections hkl values are measured for a quantification of the major orientations in a material Using all co linear reflections such as 001 002 and 004 will not suffice It is necessary to examine reflec tions along each axis such as the 100 110 and 002 Pole figure data can be used to determine the Orientation Distribution Function ODF which quantifies the orientation density of the crystal lites and provides the volume percent of crys tallites oriented in specific directions In general the ODF gives the volume part in the investi gated volume for a given orientation respec tively a given orientation range While some orientation distributions require a three dimen sional orientation representation e g Eulerian angles texture in samples such as films and fibers can often be described with a compact description of the orientation since these sam ples are either one or two dimensional in nature The texture of many films and fibers can be described by a representation known as a Fiber Texture Plot FTP while polymer orienta tion is often characterized with Hermans and White Spruiell orientation indices The pole figure s relative intensity can be nor malized such that it represents a fraction of the total diffracted intensity inte
131. dual Stress GADDS User Manual 6 5 References 1 I C Noyan and J B Cohen Residual Stress Springer Verlag New York 1987 Jian Lu Handbook of Measurement of Residual Stress The Fairmont Press Lilburn GA 1996 Baoping B He and Kingsley L Smith A New Method for Residual Stress Measurement Using An Area Detector Proceedings of The Fifth Inter national Conference on Residual Stresses ICRS 5 Linkoping Sweden 1997 Bob B He Uwe Preckwinkel and Kingsley L Smith Advantages of Using 2D Detectors for Residual Stress Measurement Advances in X ray Analysis Vol 42 Proceedings of the 47th Annual Denver X ray Conference Colorado Springs Colorado USA 1998 Bob B He Residual stress measurement with two dimensional diffraction invited The 20 ASM Heat Treating Society Conference Pro ceedings Vol 1 pp 408 417 St Louis Missouri 2000 Bob B He et al Stress mapping using a two dimensional diffraction system Proceedings of 2001 SEM Spring Conference on Experimental and Applied Mechanics Portland Oregon USA 2001 36 M86 E01007 GADDS User Manual Crystal Size 7 Crystal Size A crystallite is the smallest diffracting domain in a material Crystallite size sometimes called grain size is not to be confused with particle size A particle may be comprised of many crys tallites Crystallite size can be correlated with various thermal mechanical electrical and magne
132. e crystalline x range The area of the amor phous region is scaled to the area of the M86 E01007 GADDS User Manual Percent Crystallinity crystalline region There can be multiple oriented crystalline peaks in the crystalline region unlike the internal method The amorphous region must have no crystalline scatter within its boundaries If the sample has unoriented crystallites the external method will include this scatter in the amor phous component This will lead to a lower crystallinity If the amount of material that is randomly oriented is constant this method is still valid as a relative measure of crystal linity Set the boundary for the crystalline scatter ing Figure 8 4 y Nylon fiber Full Method PERCENT_CRYSTAL FULL The full method is best to use when amorphous scattering has texture 1 Before using PERCENT_CRYSTAL FULL collect data so that the background is well determined that is so that the pixel to pixel variation is within 3c To ensure an acceptable variation use the box cursor 11 x 11 in 1024 mode to exam ine the counting statistics The background and the mean must be within 0 4 counts and with l c l 0x1 as you move the cursor around the background regions of the frame i e non crystalline low amorphous content regions Also use the pixel cursor with the right mouse button to examine the actual pixel values at higher 20 values You should see little variation
133. e 3 9 Options for Collect Scan SingleRun window M86 E01007 GADDS User Manual Basic System Operation NOTE Get the best results by measuring at detector angles where a diffraction line is expected At these detector angles the parame ters become independent 3 Left click Process gt Calibrate The following window will display Options for Process Calibrate x Calibration filename PDF no corundum std e Minimum relative intensity 5 Auto mode Y N Sample to detector distance 4955 Delta distance ros Detector angle 00 Delta angle 000 Detector X center 508 50 Detector Y center 514 83 Delta XY movement o5 Figure 3 10 Process Calibrate 4 2 Check that the above start value for sample to detector distance is close to 4 Setthe window parameters as follows the value on the scale 4 1 Ensure that the first line points to the file corundum std This is an ASCII data file that contains JCPDS powder diffrac tion file PDF information like d spac ings and relative intensities for the corundum standard For other standard materials you can create your own std file 4 3 Ensure that the detector center is close to 512 or 256 depending on whether you use low or high resolution M86 E01007 15 Basic System Operation GADDS User Manual A CAUTION Do not change the delta angle from 0 0 Doing so would destroy the fixed factory calibration
134. e GADDS software has a 2D Scheme func tion which simulates the diffraction vectors dis tribution relative to the sample orientation S4 and S The data scan strategy can be simu lated to estimate the outcome from the stress calculation Figure 6 9 shows the input parame ters for 2D scheme Stress Peak is the approx imate value of the stress free 20 2 theta is the detector position Omega Phi and Chi are the goniometer angles Distance is the sample to detector distance frames is the total num ber of frames collected in the data scan Scan axis can be set to 2 Omega 3 Phi and 4 Chi and Frame width is the scan step The parameters in Figure 6 9 are for a 211 peak of steel sample using Cr radiation p Scan Parameters 2 theta fA 43 0 deg Omega 57 deg Phi 0 0 deg Distance fi 5 0 cm frames 7 Scan axis 2 Omec Frame width fi 5 Chi 90 0 deg Figure 6 9 The input menu of the 2D scheme function used to plan the stress data collection strategy M86 E01007 GADDS User Manual Residual Stress The 2D scheme plot from the parameters in Fig ure 6 9 is shown in Figure 6 10 The diffraction vectors are clustered along the sample axis S4 So that the data collected with the above setting will yield the best stress result for c If we col lect the data with the same o scan at 0 45 and 90 the 2D scheme in Figure 6 11
135. e PDC HI STAR controller Start the GADDS software Start the GADDS software Wait for the pro gram to establish a connection to the goni ometer 6 Goto Collect Goniometer Generator Ramp up the generator voltage and current to your settings Give the generator s high voltage a minute to stabilize M86 E01007 GADDS User Manual Basic System Operation 3 2 Selecting Optics The universal beam path concept UBC offers a variety of X ray optics For specific applications beam path brilliance monochromacy diver gence and cross section are optimized with col limators single or cross coupled G bel Mirrors monochromators Monocaps slits pinholes etc Exchanging these optics is very easy Different collimators are delivered with standard systems Replace the collimator in use as follows 1 Open the collimator clamp 2 Carefully remove the collimator tube and mount the attached labyrinth to the new col limator 3 Position the new collimator in the collimator mount 4 Ensure that any monochromator or G bel Mirror exit is fully covered by the labyrinth and that the collimator position is fixed by both the setscrew and the spring loaded clamp of the collimator mount NOTE You can replace the pinholes within colli mators with the Bruker AXS pinhole tool First remove the collimator tip and screw the pinhole tool into the pinhole and then use the pinhole tool to pull the pinholes 3 3 Cho
136. e beam size sample to detector distance and air scatter A suitable standard should have no strain particles larger than 1 um no size broadening a similar lattice type as the material to be characterized and similar X ray absorption properties With a two dimensional detector data from a standard and an unknown must be collected at the same inci dent angle angle since the peak width var ies as a function of this angle Also as a general rule the value should be selected as the 20 value of the sample reflection to be character ized For reflections below 25 20 the o value may be selected larger than 12 the 20 value to avoid unnecessarily large instrumental broaden ing caused by the large projected area of the X ray beam at low incident angles If the material is suspected to possess microstrain e g the specimen is a thin film the Warren Averbach or Single Line methods should instead be used M86 E01007 GADDS User Manual Crystal Size 7 5 3o EV WESS 7 401 Koeta mw AD H o CEES eer 25 3 s 2 theta in degrees 34 5 Figure 7 1 NIST Standard Reference Material 660 lanthanum hexaboride LaBg Profile fitting of the peak shown gives a FWHM of 0 162 with a Gaussian profile and 0 133 with a Cauchy The subtraction of the standard peak from the unknown peak has two limits depending on whether the peaks have been fit with Gaussian or Cauchy Lorentzian functions These two f
137. e fig ure then use FILE LOAD to overlay each adjoining segment Zoom in on the region of the gap in the data and examine the map of pixel intensities From those values esti mate an average intensity scale factor Reload the segment of the pole figure to be scaled using the scale factor POLE FIGURE INTERPOLATE to fill in the gap The resulting pole figure may then be smoothed using SMOOTH The recom mended option is SMOOTH CONVOLVE 4 Repeat this procedure for all pole figure segments typically 2 or 3 Save the final pole figure M86 E01007 GADDS User Manual Texture 5 8 Polymer Orientation Data collection from polymers usually differs from that of three dimensional orientation in that the orientations are usually one or two dimen sional Therefore a complete pole figure is not required to obtain orientation information The simplest orientation is that of a fiber Usually the fiber axis is close to the chain orientation direction in a fiber This is described as the meridional direction in a pole figure The direc tion normal to the fiber axis is defined as the equatorial direction Fibers are usually rotation ally symmetric In other words if a fiber were mounted along the axis the same diffraction pattern would be observed regardless of the rotation For any given 20 range a single sam ple position is required to obtain orientation information in the equatorial plane The meridi onal reflecti
138. e following define the start and end values of 2 theta and chi To determine peak position before an integra tion use Conic Cursor F9 1 Left click Peaks Integrate Chi to inte grate the 2D diffraction data into an inten sity versus 2 theta plot and to determine peak position before an integration The Integrate window appears Options for Peaks Integrate Chi x 2theta Chi Start en deg Start 84 50 deg End 51 80 deg End 74 50 deg Normalize intensity 5 Bin normalized Step size 0 050 Figure 3 15 Options for Peaks Integrate Chi window 2 Setthe intensity normalization to 5 bin nor malization M86 E01007 3 25 Basic System Operation GADDS User Manual tion System V4 1 15 Copyr 1997 2003 Bruker Analyze PE j Eia Jern Hels SrMnO3 films Corundum 500snout 00 001 gfrm 02 13 04 08 56 10 Created 01 28 04 Mag Quad 1 0 2 Theta 40 000 Width 0 0000 Counts 1290000 Time s 120 00 Distance 14 950 Size 1024 GADDS General Area Detector Diffrac Brodec ile Edit Collett Process 2th begi 23 800 2th en 55 900 chi begi 120 60 chi en 58 700 Distance 14 800 FloodFld 1024_015 Spatial 1024_015 1024x1024No HISTAR 1 2 3 4 Select edge M Move ENTER L button Integrate ESC O buttons Quit Figure 3 16 Define the values of 2 theta and chi 3 26 M86 E01007 GADDS User Manual Basic System Operation 4 Press Enter A typical plot is shown in Fig ure 3 17
139. e following description you will change the mapping parameters to fit the FWHM of a selected peak throughout a data set 12 2 1 Frames to Process First frame first frame of the data set you want to analyze To frame number frame number of each frame from the data set typically 000 To run number run number of the last frame from the data set the software defaults to the last run in the series NOTE If the default run number is not true for this series of frames then the number of char acters in Run needs to be changed to the appropriate value under Edit gt Configure gt User Settings 12 2 2Processing Parameters Map Parameter Peak FWHM Mapping Options Type in Start and End values of both 2 theta and Chi for the peak you want to get FWHM information from or say OK Select them by choosing 1 2 3 or 4 and moving the mouse M86 E01007 GADDS User Manual Mapping 3 Choose 5 Bin Normalized and an appropri ate Step Size for the detector position PEAKS AUTO options Figure 12 3 PEAKS AUTO options 4 Hit OK within the PEAKS AUTO options window to perform the operation If you receive an error message then there is most likely no profile pro calibration file to profile fit the peak M86 E01007 42 5 Mapping GADDS User Manual e To set up a Calibration file go to Special Command mode in the GADDS software 5 1 Type PEAKS into the command line 5 2 Hit enter an
140. e most critical part of the operation is to find a suitable pinhole collimator to reduce parasitic scattering but not sacrifice too much of the beam intensity Ideally you should use the smallest available collimator 50 um or 100 um The limiting factors are data collection time and desired resolution While the pinholes cannot be repositioned within the standard collimator tube you may try different combinations of pinholes to reduce parasitic scatter The beam stop diame ter 4 mm and the available collimator sizes limit the achievable resolution This resolution is 200 250 A at the edge of the beam stop for a He beam path with the detector positioned at 30 cm using 1024x1024 frames and copper radiation Performing a Flood Field Correction Initial flood field and spatial corrections were done before installation of the beam stop and the beam path and these corrections may be adequate depending on your needs For instance some users collect flood field data with the beam stop in place while others con tend that a linear flood field is adequate with the detector at 30 cm and beyond The same holds true for the spatial correction with the fiducial plate However if the scattered image occupies only the center part of the detector and you wish it to cover more you can use an alternate cor rection method to refine the flood field and obtain smoother images You initiate that method with the FLOOD REPROCESS 1 2 XMIN YMIN
141. e overlap of the crystalline and amorphous regions i e in frames containing a continuous Debye ring and only for materials with a single crystalline peak or unresolvable peaks in the crystalline region While this method can be used for oriented peaks the external method is better suited for such materials For unoriented materials the start and end y values for the background must equal those of the peak Oth erwise the region bounded by the difference in the x values is also considered amorphous M86 E01007 Percent Crystallinity GADDS User Manual Before using the internal method you ll need to determine the boundaries To deter mine the boundaries of the crystalline and amorphous regions integrate the areas using PEAKS or DIFFRAC Profile an optional package and use profile fitting to deconvolve the crystalline and amorphous peaks If you use PEAKS do not use the default peak function which is too sharp Instead model the peak with PEAKS SIMU LATE with an appropriate FWHM The final fitting will show the extent 20 lim its of both peaks Enter these values for the lower and upper limits of this function Set the crystalline peak 20 limits but not so far out that the polynomial option for the amorphous background would be modeled as a straight line One approach to deter mine if you ve met this condition is to first compute the crystallinity based on a linear background then compare the result
142. e smearing effect caused by y weld 718 Stress wel718fu 007 1024x1024 17 38 12 10 17 97 m eo o o o H HM N NNN ww 10 000 1024 010 1024 010 No PDC ESC O buttons Quit integration in the conventional method can be minimized by using the 2D method In the con ventional method the y integrated profiles are treated as if the data were collected within the diffractometer plane y 90 While in the 2D method the data points along the diffraction ring are treated at their exact y values 6 10 M86 E01007 GADDS User Manual Residual Stress The diffraction frames collected with a 2D detec tor contain both stress and texture information Two functions can be derived from the diffrac tion ring One is the peak position as a function of y 20 20 y which is uniquely determined by the stress tensor and the sample orientation Another is the integrated intensity as a function of y I y which is determined by the sample texture Figure 6 7 shows four frames collected from samples with no texture weak texture strong texture and very strong texture For the case with very strong texture the conventional diffractometer using a scanning point detector or PSD will miss the diffraction ring so as not to be able to measure the diffraction peak For mild texture the virtual oscillation can be used for the stress calculation For strong texture the diffrac tion profiles integrated over a large y
143. eam path attached on the beam stop assembly Micrometer feedthroughs Figure 9 3 Helium beam path for small angle X ray scattering measurement The cross section shows the beam stop and adjustment micrometer feedthroughs The beam stop is attached through nylon wires to two linear motion feedthroughs The beam stop can be positioned accurately to the X ray beam center In order to reduce the air scatter ing a He beam path is normally attached to the beam stop assembly as follows M86 E01007 Small Angle X ray Scattering GADDS User Manual Attach the beam stop to the detector first ensuring that the beam stop flange mounts flush against the gasket on the detector face Apply a small amount of vacuum grease to the gasket surface before attaching the Plexiglas cones This ensures a gas tight seal If the gasket does not have precut holes through which the alignment pins for the fiducial plate extend then remove the align ment pins And use the threaded standoffs to secure the beam stop assembly to the detector Attach the Plexiglas cone to one of the Plexiglas rings before inserting the ring in the Plexiglas base Grease the large O ring then insert it in the groove on the Plexiglas base Attach the Plexiglas assembly to the beam stop using four long screws The orientation should be such that the gas inlet and outlet tubes are vertical The range of the sample to detector distance for
144. ed with a Cu tar get Table 2 4 Focal spot brightness for sealed tubes and rotating anode sources with Cu target off angle for typical X ray tubes used with Source Focal Spot Maximum Maximum GADDS t Size Load kW Brightness Systems mm x mm kW mm Table 2 3 Focal spot size line focus size and spot focus Normal focus 1x10 20 0 2 size of some typical X ray tubes Fine focus 0 4x8 1 5 0 5 Tube Type Focal Spot Line Focus Spot Focus Long fine focus 0 4 x 12 25 0 5 Size at Anode Size Size mm x mm mm x mm mm x mm Micro focus 0 15 x8 0 8 0 7 Normalfocus 1x10 0 1 x 10 1x1 Rotating 0 5 x 10 18 0 3 6 Anode Fine focus 0 4x8 0 04 x 8 0 4 x 0 8 Generator 0 3x3 54 6 0 Long fine focus 0 4 x 12 0 04 x 12 0 4 x 1 2 0 2x2 3 0 7 5 Micro focus 0 15x 8 0 005x8 0 15x 0 8 0 1 x 1 12 12 0 As shown the micro focus sealed tubes have the brightest focal spot of all sealed tubes Rotating anode generators have very high bril liance compared with sealed tubes The inten sity over the focal spot is not evenly distributed M86 E01007 2 5 System Configuration GADDS User Manual The focal spot profile is the intensity distribution over the area of the beam cross section and is eventually translated to the beam profile The beam profile is sometimes very important to the diffraction result The focal spot profile across the beam from fine focus and long fine focus sealed tube a
145. em This is an example of residual stress measure ment with the GADDS Microdiffraction System The residual stress on the inside surface of a spring was measured with Cr tube and 0 3mm collimator Since the size of the spring is rela tively small coil diameter 10mm wire diameter 1mm and coil pitch 4mm the Laser Video Sam ple Alignment System was used to position the inside surface of the spring The spring was made of precipitation hardenable stainless steel 17 7PH The 211 diffraction ring of the alpha phase was used for stress measurement Figure 6 22 shows the laser spot on the inside surface of the spring wire When the laser spot is in the center of the crosshair the sample sur face is aligned to the goniometer center Figure 6 22 The image from the laser video sample alignment system Figure 6 23 shows a part of the spring The inci dent X ray beam and diffracted beams can pass through the gap between spring wires so the residual stress can be measured nondestruc tively Figure 6 23 The video image showing a section of the spring The diffracted beams can pass through the gap between the wires M86 E01007 GADDS User Manual Residual Stress Figure 6 24 shows one of the measured frames with chi integrated profile The broken blue lines indicate the shadow of the wires For data eval uation the frames were first processed with the GADDS stress function and then imported to DIFFRAC S STRE
146. em a set of pinhole collimators and pinhole slits convert the line focus beam into a point focus beam Figure 2 7 b shows the cross coupled G bel mirrors used for an X ray source with point focus where a second G bel mirror turned 90 collimates the beam in the direction perpendicular to the first mirror M86 E01007 GADDS User Manual System Configuration V x ray source 1 first mirror Se second mirror X ray source point focus b Figure 2 7 a A single parabolically bent G bel mirror transforms the divergent primary beam from source into a parallel beam b In the cross coupled G bel mirrors the second G bel mirror turned 90 collimates the beam in the direction perpendicular to the first mirror M86 E01007 System Configuration GADDS User Manual For all applications requiring strong collimation of the beam G bel mirrors provide considerable intensity gains Experimental results show that the smaller the beam size the stronger the intensity gains from cross coupled G bel mir rors compared with a monochromator Figure 2 8 Therefore the cross coupled G bel mirrors are especially suitable for microdiffraction and small angle X ray scattering The specifications of G bel mirrors for various applications are listed in Table 2 24 The intensity break even point for G bel mirrors versus standard pinhole collimat
147. emperature stage a high temperature stage a Helium or vacuum beam path for SAXS a beam stop and align ment and calibration fixtures The whole system is controlled by a computer that uses GADDS software D8 DISCOVER with GADDS designed for speed precision flexibility versatility and reli ability is the new generation of our GADDS products The following sections will introduce the five major units several standard systems and some accessories based on the D8 series Due to the large variety of customer needs and the availability of new technologies and new components that make for numerous system combinations this section introduces only the most commonly used GADDS components Refer to other documents the GADDS Adminis trator Manual or consult our service personnel for components not covered M86 E01007 GADDS User Manual System Configuration 2 1 X ray Generator white radiation and characteristic radiation lines K and Kg and b K line a combination of two lines K 4 and Kj The X ray generator produces X rays with the required radiation energy focal spot and inten The spectrum consists of continuous radiation also called white radiation or Bremsstrahlung oe and a number of discrete characteristic lines 2 1 1 Radiation Energy For X ray diffraction the three most important GADDS can use a variety of X ray sources characteristic lines are K 4 and K 5 and Kp The from a sealed tube generator t
148. ences of 1 with the first text string 2 with the second text string and so forth Typically one modifies an existing script to use replaceable parameters When inserting replaceable parameters into a script file keep these rules in mind e You must delimit replaceable parameters with either spaces or single quotes within the argument value e If you wish to concatenate text and replace able parameters into a single argument value then you must use single quotes see last two rules e You may use a replaceable parameter to represent the entire argument value as in TITLE 1 e You may use a replaceable parameter to represent part of the entire argument as in FILENAME 261 001 e You may use more than one replaceable parameters in the argument value as in FILENAME 961 962 3 To execute a replaceable parameter script you would enter a command in the following format at the command mode prompt Q filename parm1 parm2 parmO where filename is the script file s filename slm is assumed parm1 is the text for 1 parm2 is the text for 2 parmo is the text for 0 For example if one enters PhaselD Unknown sample XYZ 1 00 00 SLAM replaces all occurrences of 961 with Unknown sample XYZ and 2 with 1 00 00 within the file PhaselD slm When using a script with replaceable parame ters keep these rules in mind 10 16 M86 E01007 GADDS User Manual Script Files You mus
149. ent The polymer sheet should be aligned similar to that of a fiber except that a machine direction should be set along the axis Once the sheet is in place so that the sheet normal is along the microscope axis update 0 with COLLECT GONIOMETER UPDATE Use POLE FIGURE SCHEME to plan the data collection strategy and use POLE FIGURE PROCESS to obtain the pole figure If the sheet is supported make sure the X ray beam does not hit the frame dur ing rotation otherwise an intensity of zero will be merged with a positive intensity collected at another orientation M86 E01007 GADDS User Manual Texture 5 11 Near Single Crystal Thin Film Orientation Orientation and texture are usually synonymous terms for the distribution of crystallites with respect to a sample direction For large single crystals or single crystal wafers orientation refers to the tilt of the crystallographic axis with respect to the sample surface In some cases two or more angles are necessary to define the orientation of the crystallographic axis to the sample axes These measurements are neces sary in quartz oscillators and single crystal tur bine blades The determination of these values is typically performed by Laue diffraction where the complete X ray spectrum from a tungsten X ray tube is used Laue was the first X ray diffrac tion technique used for characterization It is fast and is usually used in 100 industrial inspection applicat
150. ep size 0 05 Y 2 Figure 4 5 Peaks Integrate Chi Integration M86 E01007 GADDS User Manual Phase ID 11 Save the integrated scan in a separate file Use the DIFFRAC format 12 Repeat the last step for each frame Make manual sure you keep step width and integration mode constant The 20 ranges have to over lap in at least one point The End value of one range has to match one step of the next range 13 Use the Merge software tool to merge the scans GADDS General Area Detector Diffraction System V3 329 Copyr 1997 98 Bruker Ele Edt Collect Process Andyze Peaks Special User Help GADDS General Area Detector Diffraction System V3 329 Copyr 1997 98 Bruker Eje Edit Colect Process Andyze Peaks Speciel User Help 1 2 3 4 Select edne FNTFR hutton Tntenrate FSC Other E 1 2 3 4 Select edne M Move FNTFR hutton Tntenrate FSC Figure 4 6 Measured diffraction patterns 14 Use DIFFRAC S Eva to perform the data base search See the DIFFRAC 4S EVA Figure 4 6 shows a measured diffraction pattern from a textured sample surface The integrated diffraction spectrum is a function of the selected integration range GADDS General Area Detector Diffraction System V3 329 Copyr 1997 98 Bruker Eie Edit Colect Process Analyze Peake Special User Help 1 7 3 4 Select edne FNTFR I hutton Tntearate FSC other M86 E01007 Phase ID GADDS User Manual Figure 4
151. er the symbol You may follow the filename with the optional replaceable parameters as will be explained later in section 10 4 The methods for entering into command mode and starting a script file are as follows e Ifyou are already working in GADDS you can execute the Special gt Command Mode command which will change GADDS oper ation from menu mode to command mode The menu bar becomes gray disabled and the command prompt GADDS gt appears at the bottom of the window where you enter the script command e You can start GADDS with the startup quali fier COMMAND to immediately enter into command mode when starting GADDS Then you enter the script command at the command prompt GADDS gt e You can start GADDS into command mode and immediately start executing the script by using the startup qualifier with the script command attached for example GADDS COMMAND Q PhaselD M86 E01007 Script Files GADDS User Manual e You can setup and use the script as a user task as explained in section 10 5 To interrupt a script while it is executing press the control key combination lt CTRL C gt or lt CTRL BREAK gt This will stop the script execu tion and exit from the script returning the user to the program s command line prompt To exit command mode and return to menu mode simply type menumode and Enter on the command line by the GADDS gt prompt You may wish to add this Menumode co
152. erature M86 E01007 GADDS User Manual System Configuration 2 8 Standard GADDS Systems for Combinatorial Screening Combinatorial chemistry refers to techniques to fabricate test and store the resulting data for a material library containing tens hundreds or even thousands of different materials or com pounds Combinatorial investigations require rapid screening techniques to test and evaluate variations of composition structure and property within a material library X ray diffraction is one of the most suitable screening techniques because abundant information can be revealed from the diffraction pattern and X ray diffraction is fast and non destructive The concept of combinatorial chemistry was introduced about 30 years ago Instead of the traditional way of making and testing a few new materials one at a time the combinatorial tech nology allows scientists to fabricate test evalu ate and store the resulting data for a material library containing tens hundreds or even thou sands of different materials or compounds Combinatorial chemistry has become increas ingly accepted by academia government and industry in the past few years Excellent results have been achieved in the discovery and syn thesis of new phosphors catalysts zeolites and new drugs Combinatorial chemistry requires rapid screening techniques to test and evaluate the variation of composition structure and prop erty of the entire mater
153. ering and cross contamination The retract able knife edge is mounted on the stationary base independent of the sample translation stage so the knife edge stays at the same aligned position while each cell of the combina torial library moves into the X ray diffraction measurement position The retractable knife edge can be driven to two positions retracted position and extended position In retracted position a laser video alignment system aligns each cell to the instrument center In extended position the knife edge collimates the X ray beam for low angle diffraction The motorized retractable knife edge makes it possible to scan over the whole combinatorial library with auto matic sample alignment In the low angle diffraction measurement the incident X ray beam is spread over the sample surface into an area much larger than the size of the original X ray beam In combinatorial screening applications sample cells are located close to each other so the spread beam may cause cross contamination in the collected dif fraction data Therefore it is necessary to use a knife edge to limit the diffracted area Figure 2 27 shows the front view of the retract able knife edge in a 2D X ray diffraction system M86 E01007 GADDS User Manual System Configuration Figure 2 27 Front view of the retractable knife edge ona 2D X ray diffrac
154. et i e well the sample information for that target gets loaded using the FILE feature of the Scan command by passing FILE filename for the title parameter Start data acquisition by sending the winsocket command M 96WellsCollect lt jobname gt lt scantime gt lt FILE filename gt lt platename gt lt barcode gt MCP monitors the GADDS log stream When the data acquisition finishes start data processing in a separate process by send ing the commands w c saxi gaddsnew gadds thetatheta nodif com 96WellsProcess lt plateid gt You do not have to wait for process ing to terminate just load and start the next library 11 5 Audit Trails GADDS produces audit trails for instrument con figuration alignment and calibration changes Your MCP must create audit trails for sample tracking M86 E01007 GADDS User Manual Mapping 12 Mapping Mapping involves the comparison of multiple samples to each other using a predefined fea ture or characteristic of the data set The most common examples of these features include but are not limited to peak area peak 20 and peak FWHM By defining one such criterion the GADDS software is then able to extract that information from each frame of a data set In order for the software to function correctly the scans are required to be consecutive in run number as they would be in a grid targets array However each sample spot measured can be unique and not pa
155. f filament the focal spot is categorized as normal focus fine focus long fine focus or micro focus Forward Diffraction The diffraction condition when 20 lt 90 Four Circle Geometry Sample can be rotated about three axes omega phi and chi independently and detector can be rotated about a fourth angle two theta concentric with omega GADDS General Area Detector Diffraction System also refers to General Area Detector Diffrac tion Software Goniometer An instrument for measuring and moving angles Goniometer Head A device for aligning a sample by means of translation motion and in some models moveable arcs Integrated Intensity The total intensity measured at a given angular range such as chi integration 2theta integration and area integration Laboratory Coordinates The rectangular coordinate system in a dif fraction system with three axes X Y and ZL X is the direction of the incident X ray beam X Y plane defines the diffractome ter plane and Z defines the omega and two theta axes Lattice Plane The repeating two dimensional atomic arrangement within a crystal Also called crystal plane Least Squares Fitting Method A statistical method of obtaining the best fit of a large number of observations to a given equation This is done by minimizing the sum of the squares of the deviations of the experimentally observed values from their respective calculated ones L
156. figuration Table 2 11 Beam divergence 20 spread in as a function of o and 20 with a 0 2 mm collimator 30 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 1 40 20 40 60 80 100 120 140 160 1 12 83 0 01 0 04 0 09 0 17 0 23 0 27 0 27 0 24 0 18 0 10 2 6 42 0 02 0 04 0 08 0 12 0 13 0 13 0 12 0 09 0 05 5 2 57 0 01 0 03 0 04 0 05 0 05 0 05 0 04 0 02 10 1 29 0 01 0 02 0 03 0 03 0 03 0 02 0 01 20 0 65 0 01 0 01 0 01 0 01 0 01 0 01 30 0 45 0 01 0 01 0 01 0 01 0 01 40 0 35 0 01 0 01 0 01 0 01 50 0 29 0 01 0 01 0 01 90 0 22 Table 2 12 Beam divergence 20 spread in as a function of and 29 with a 0 3 mm collimator 30 cm sample to detector distance and 1024x1024 frames Apparent 20 Size mm 4 1 40 20 40 60 80 100 120 140 160 1 19 25 0 02 0 06 0 13 0 26 0 35 0 40 0 40 0 36 0 27 0 15 27 9 63 0 01 0 03 0 06 0 13 0 17 0 20 0 20 0 18 0 14 0 08 5 3 85 0 01 0 02 0 05 0 07 0 08 0 08 0 07 0 06 0 03 10 1 93 0 01 0 02 0 03 0 04 0 04 0 04 0 03 0 02 20 0 98 0 01 0 01 0 02 0 02 0 02 0 02 0 01 30 0 67 0 01
157. files see the demo loop script files located in the GADDS TEST directory default is C saxi gadds32 or see the examples later in this section 10 4 SLAM Command Conventions Each command within a script is entered in the SLAM command line syntax which is similar to the DOS command line syntax and to DCL under VMS You use this syntax to enter com mands in either a script file or on the command line at the GADDS gt prompt You do not use any special words for example begin or end in the script Branching logical and con ditional statements Flow Control was not allowed prior to release 4 0 14 Flow control is discussed later in Section 10 7 To understand a SLAM command you must become familiar with each component of a com mand Either a space or a required slash delim its each component For readability we recommend always using spaces to delimit SLAM components Command verb Appearing first the command verb also called name identifies the command or group of commands and has the form name You may abbreviate the verb but the verb must have enough characters to be distinguished it from all other legal com mand verbs Subcommand Whenever the verb designates a group of commands it is immediately followed by a subcommand which must begin with a slash character and has the form lt name gt M86 E01007 GADDS User Manual Script Files Commands will either always take a
158. for examining pole figures displayed in stereographic projection because a circle represents a constant area on a sphere This is not the case if the pole figure is displayed in polar projection This cursor pro vides the total intensity average intensity peak to background ratio I Sigmal and centroids in screen coordinates and stereographic angles It can be used to compare the intensity of a line at specific orientations For example to determine the intensity ratios of 111 to 200 for planes at 45 a in a drawing direction set the cursor at 45 a 0 B and compare the total intensities normalized by the 111 to 200 intensity ratio from the PDF card to account for structure factor differences Another application would be to examine an area of 10 solid angle at the center of a pole figure and compare it to the same solid angle at 54 74 a This would give the ratio of crystallites e g 1 1 2 1 in these two direc tions CURSOR CIRCLE can also be used to deter mine the tilt and twist of single crystal films Fig ure 5 10 shows the 111 pole figure from an epitaxial thin film on a Si substrate CURSOR CIRCLE can be used to determine the a and p centroids for the film and substrate reflections The difference in the a centroids gives the tilt of the film with respect to the substrate The differ ence in the p centroids gives the twist of the film with respect to the substrate This analysis is valid only for cubic ma
159. for the MERGE utility Then modify the line to read SYSTEM GADDSSSYSTEM merge corund raw corundMerged raw 16 Now we could simplify the script file some 17 Print the script file again what by deleting duplicate qualifiers from subsequent re issuance of the same com mand For example the second SCAN SINGLERUN command does not need to contain the qualifiers PHI 0 0 CHI 0 0 WIDTH 10 0 SCANTIME 1 00 00 RUN 0 DISPLAY 16 REALTIME CLEAR These arguments are not required and can be omitted The program will thus default to the settings used in the first SCAN SIN GLERUN command However we will leave the script as is M86 E01007 10 13 Script Files GADDS User Manual 18 Save the file and close NotePad The script should now look like PhaseID slm Qualitative Phase Identification Script File Version 1 0 Created by KLS 06Jan98 Last modified by no one This script will collect 4 frames at 20 45 70 95 deg integrate and merge results into a single range RAW file for input into EVA s search match routine Step 1 define a new project GADDS 4 users only PROJECT NEW CNAME Corundum 0 TITLE Corundum Test Sample amp WORKDIR SPROJECT FORMULA MORPH CCOL DENSITY amp DENSMETH CLEAR RESET Step 2 collect the frames and unwarp SCAN SINGLERUN 1 2THETA 20 0 OMEGA 5 0 PHI 0 0 CHI 54 74 AXIS 2 amp WIDTH 10 0 SCANTIME 1 00 00 TITLE Corundum Test Sample amp
160. for the Texture Experiment Consult the JCPDS ICDD database and exam ine the PDF card for the material If the card is not in the PDF file then collect a standard pow der diffraction scan rotating the sample in while scanning in Set y 54 74 to sample a larger unique section of reciprocal space than can be observed with y 90 For alloys and non stoichiometric materials PDF cards fre quently do not exist though there may be cards for related materials For thin films always determine the line positions because the layer of interest may have infused material causing peak shifts from the phase pure material To determine optimal data collection parame ters it is recommended to collect several frames with the sample in different orientations with respect to the X ray beam if possible at differ ent y settings In this way for example intense single crystal substrate peaks may be avoided For highly textured materials such as many electronic thin films it is important to scan over a 5 15 range to observe the textured reflections In summary confirm the phases present and get an overview of the orientation M86 E01007 Texture GADDS User Manual 5 4 Data Collection Considerations for ODF Analysis Pole figures collected for ODF analysis using the popLA software must cover at least 70 a For other programs the requirement may be as high as 80 a Consult the specific ODF soft ware documentati
161. g another Col lect gt Scan gt SingleRun command using 45 for 20 17 5 to 27 5 for o and 002 for frame number Collect the third frame using another Collect Scan SingleRun com mand using 70 for 20 30 to 40 for w and 003 for frame number Collect the last frame using another Collect Scan SingleRun command using 95 for 20 42 5 to 52 5 for c and 004 for frame number SCAN SINGLERUN options x Frames pooo 2 Theta o deg Omega fo deg Phi poo deg Chi ooo deg x0 000 Y 0 000 z 0 000 Aux 0 000 Scan Axis je Frame width oo Seconds frame fi 700 00 Bc orundum Tesi Sampie O Sample name Corundum Sample number MEN Job name coruna Run NN Frame zoo Max display counts ps iv Realtime display YN Iv Pre clear Y N T XENGEN output format Y N Mode ScanjOscillate Step Rotate sample Y N Capture video image Figure 10 3 SCAN SINGLERUN options M86 E01007 10 9 Script Files GADDS User Manual 7 For GADDS 4 0 users skip to step 8 For GADDS 3 X users only you will need to unwarp the frames next Use the Spatial gt Unwarp command specifying the first file name corund0 001 and the number of frames as 4 We will assume GADDS 4 0 and skip this command 8 Integrate each frame into a multi range raw file This requires a File gt Load and Peaks gt Integrate gt Chi commands for each frame e Use File gt Load to load the first
162. g data collection Save the video image into files System alignment Laser video Microscope Video features Magnification 40 280x 1 26 CCD 136 display Computer controlled zoom lens 1 7x Working distance 78 mm Field of view 6 0 9 mm Color video camera NTSC Picture element 768H x 494V Horizontal resolution gt 460 TV lines Frame grabber and image software User selectable video reticles Laser features Beam size lt 20 mm Variable neutral density filter manually adjustable from 10 to 80 transmis sion Laser pointer for accurate sample positioning suitable for reflection samples Micro sample and micro area alignment Monitor the sample during data collection Save the video image into files System alignment M86 E01007 33 System Configuration GADDS User Manual 2 5 HI STAR Area Detector The HI STAR Area Detector is a two dimen sional multiwire proportional counter MWPC and is the core of a GADDS system Figure 2 13 2 28 lists the specifications of the HI STAR area detector compared with a typical scintillation detector and PSD Table 2 29 lists the angular resolution for various detector distances Table 2 28 Specifications of HI STAR area detector some properties are compared with typical PSD and scintillation detector Specifications HI STAR PSD Scintillation Data format 2D
163. g on the detector face additional data must be collected usually at a second o value With a cradle when planning coverage using POLE FIGURE SCHEME change y first and o second At distances larger than 6 cm three or more values may be nec essary A typical second o value is 1 20 X with X 5 To fill in the center or north south poles of a pole figure the value of X increases as the y value decreases Adjust the value until the simulated pole figure is complete The cen tral part of the pole figure in reflection mode is always attainable at y 90 by setting 0 If rotation is available a 180 scan in 6 will give the complete central portion of the pole figure to a given B value The Projection Direction PD indicates the rela tionship of the sample normal to the X ray beam PD 1 is defined as the sample normal being parallel to the x ray beam when y 0 This is usually specified when examining poly mer sheets in transmission or with fibers PD 3 M86 E01007 Texture GADDS User Manual is defined as the sample normal being coinci dent with the z axis of the goniometer which is vertical In cases where both transmission and reflection pole figure data is collected the data should be processed as either PD 1 or PD 3 If the sample requires remounting POLE_FIGURE TILT and POLE_FIGURE ROTATE may be necessary to orient the pole figure properly with respect to the original sam ple set
164. get Material Detector to Sample Distance Cu optional Co Cr 6 cm to 30 cm Cu optional Co Cr 6 cm to 30 cm Cr optional Co Cu 6 cm to 30 cm Cu optional Co Cr 6 cm to 30 cm Measuring Range 20 65 at 6 cm detector distance 18 at 30 cm detector distance Resolution 20 0 10 at 6 cm 1024x1024 0 20 at 6 cm 512x512 0 02 at 30 cm 1024x1024 0 04 at 30 cm 512x512 Max Measurable 20 161 depending on the detector distance Smallest Step Size 0 0001 Reproducibility 0 0001 M86 E01007 System Configuration GADDS User Manual Table 2 31 Application Features of the five standard GADDS systems Applications Basic Fixed Chi Microdiffraction Stress Texture Eulerian 4 Cradle Large or Small Sample Type Powder in glass capillary Small or large samples Powder in glass capillary Small or large samples and Handling without preferred orienta thin films large wafer without preferred orienta thin films large wafer tion small or medium plate multiple samples tion small or medium plate multiple samples samples flat plate or accurate sample area samples flat plate or accurate sample area curved surface films foils selection alignment and curved surface films foils selection alignment and or fibers mount in trans video monitoring auto or fibers accurate sample video
165. grated over the pole sphere Typically the pole sphere is stereo graphically projected to the pole figure but you can also use polar projection for non standard uses Three projection directions are supported depending on how you mount your sample on the goniometer For fibers and wires project the pole sphere along X 1 For flat samples deter mine the direction of the sample normal typi cally either along X 1 or 2 3 Additionally you can tilt invert and rotate the projection of the pole sphere until you get the projection required M86 E01007 GADDS User Manual Texture In a pole figure displayed with the GADDS soft ware the angle alpha a is defined as the angle between the normal to the reflecting plane of interest that is the pole of interest and a phys ical reference plane in the sample for projec tion 3 the sample surface see Figure 5 1 a 90 y Figure 5 1 Definition of the angles a and p and stereographic projection For example in a cubic system a 100 pole fig ure which has intensity at o 90 implies that the 100 direction is normal to the surface A 111 pole figure from this sample would have intensity at a 54 74 which is the angle between the 100 and 111 directions The angle beta p is the angle between the normal to the reflecting plane of interest and a second reference direction orthogonal to the first direc tion usually a machine direction MD
166. he chain orientation direction in a fiber This is described as the meridional direction The direction normal to the fiber axis is defined as the equatorial direction Fibers are usually rotationally symmetric In other words if a fiber were mounted vertically the same diffraction pattern would be observed regardless of the setting For any given 20 range a single sample position is required to obtain orientation informa tion in an equatorial plane The meridional reflections usually have a maximum intensity at the Bragg angle This means that for an arbi trary sample position with respect to the incident beam different percent crystallinities would be determined based on the amount of the meridi onal reflection in the scan To determine the percent crystallinity all reflections that are not on the equator must be scanned The scanning of the sample introduces a pseudo randomiza tion of the pattern The equatorial amorphous and random components have one Lorentz cor rection and the meridional reflections have another In order to weight these classes of reflections appropriately 1 Determine the angle of rotation about or o that includes the meridional reflections for the same time as the equatorial reflections This is equivalent to having a powdered specimen 2 Determine the breadth of the rocking curve of the meridional reflections 3 Setthe scan range in COLLECT SCAN to start at 1 2 the reflection breadth f
167. he diffraction pattern will extend from 5 to 110 degrees in 20 Next you need to integrate the frame files into raw files Finally you need to merge the raw pattern into a single range for inputting into the search match rou tine Such mundane repetitiveness is ideally suited to using script files So let s create a script for this purpose Decide which functions you wish to auto mate By writing down the sequence of commands you are less likely to omit a cru cial step or invert the required order of com mands In our case we need to use Scan gt SingleRun to collect all the frames one each at 20 45 70 and 95 degrees in 20 Spatial gt Unwarp to unwarp the frames prior to integration Under GADDS 4 0 this step is automatically done during the scan com mand but GADDS 3 X users must include this step File gt Load amp Peaks gt Integrate gt Chi for each frame to convert each frame into a raw range The external MERGE utility to convert the multi range RAW file into a single range RAW file The external EVA program in batch mode to perform the search match operation Place your sample on the instrument or use the corundum sample Optically align the sample Because there is no automated way of mounting and aligning your sample we will create the script procedure to begin after the GADDS user manually did this step Place GADDS menu s into level 2 using the Special Level 2 command M86 E010
168. he resolution R defined as the theoretically largest Bragg spacing is given as R Notmax 9 7 where A is the wavelength of the X ray radiation Ris so chosen that for a lattice spacing smaller than R the angle between two consecutive orders of Bragg reflections is larger than aa The actual achievable resolution is also limited by the beam stop size B and the resolution limit of beam stop Rgs is given as 2L Res X B 9 8 The typical beam stop size is 4 mm in diameter for the GADDS He beam path and vacuum beam path The pinhole scattering is defined as the scattering from the pinhole materials sec ond pinhole in Figure 9 1 beamstop sample Pinhole collimator L T Figure 9 1 Pinhole collimation for SAXS M86 E01007 detector Small Angle X ray Scattering GADDS User Manual The region of the pinhole scattering is limited by Table 9 1 The resolution power of various SAXS the anti scattering pinhole third pinhole The configurations size of the anti scattering pinhole should be Sample Detector Distance L 300 mm small enough to block as much pinhole scatter Collimator D mm R Rps ing as possible but not so small as to touch the a a i A ERR PRU Graphite Monochromator primary beam The pinhole scattering observed as a halo around the shadow of the beam stop 0 05 0 04 0 071 0 09 951 231 is also called par
169. hi range measured simultaneously m measurement of oriented samples m very short measuring times 44 um intensity versus 20 by Figure 1 4 Coverage comparison point line and area detectors integration of the data M86 E01007 Introduction and Overview GADDS User Manual 1 3 Geometry Conventions 1 3 1 Diffraction Cones and Conic Sections on 2D Detectors Figure 1 5 shows the geometry of a diffraction cone The incident X ray beam always lies along the rotation axis of the diffraction cone The whole apex angle of the cone is twice the 20 value given by the Bragg relation The surface of the 2D detector can be considered as a plane which intersects the diffraction cone to form a conic section D is the distance between the sample and the detector and a is the detec tor swing angle also referred to as the detector 20 angle The conic section takes different shapes for different o angles When imaged on axis a 0 the conic sections appear as cir cles producing the Debye rings familiar to most diffractionists When the detector is at off axis position a 0 the conic section may be an ellipse parabola or hyperbola For conve nience all kinds of conic sections will be referred to as diffraction rings or Debye rings alternatively hereafter in this manual All diffrac tion rings collected in a single exposure will be referred to as a frame The area detector image frame
170. his is not done the pole figure can be tilted during data processing to orient the MD vertically in the pole figure The collimator tip may be removed to allow more sample clearance Using the manual control box verify that the SCHEME recommended measuring param eters do not cause collisions with the cur rent instrument configuration If the two position y stage is used verify that the appropriate y angle is set both on the stage and in the software Use collect goniometer fixedaxis to update x If pole fig ure data has been collected at any wrong fixed angle the value may be corrected with the FRMFIX utility Use filename to pro cess an entire series of frames When using an oscillator make certain the sample is securely fastened to its holder The Trans Rot oscillator for the two position y stage must be secured to the stage with its support rails After repositioning x on the two position x stage the sample height should be read justed After adjusting the sample height with the threaded knurled specimen mount M86 E01007 GADDS User Manual Texture for the oscillator snug down the set screw on that mount Use GONIOMETER UPDATE whenever the specimen is physi cally rotated e Verify that the angle is not so shallow that closely spaced peaks are overlapped due to broadening If a 4 cradle is used it is rec ommended to vary y rather than o to mini mize peak broadening 5 3 Preparation
171. hod may be used to determine the ori entation not only in polymers but also in other fibrous or sheet like materials It has been used on polypropylene sheets and talc many differ ent types of fibers and on films comprised of layers of different polymers In a multilayer the orientation of each layer can be determined as well as how each layer aligns itself with the layer below it This experiment is done using the o angle optimized to observe the specific layer similar to a glancing angle experiment Another application is the determination of the orienta tion of a mineral within a cut block The machine direction in this case is the direction that the sample was cut and is not related to any observed growth pattern M86 E01007 GADDS User Manual Texture 5 15 Fiber Texture Plots X ray diffraction can provide the orientation of a film with respect to its substrate The technique involves collecting pole figures Figure 5 12 which are stereographic representations of the grain orientations in three dimensional space The HI STAR area detector can collect large sections of many diffraction cones simulta neously which enables a complete range of grain orientations to be observed Figure 5 12 Al 111 on Si 100 substrate M86 E01007 Texture GADDS User Manual Texture strength can be quantified using Orien tation Distribution Function ODF software At least three pole figures are required for ODF a
172. ial library X ray diffrac tion is one of the most suitable rapid screening techniques because of the penetrating power of the X ray beam it is nondestructive to samples data collection is rapid and there is a lot of use ful information about the materials contained in the diffraction pattern X ray diffraction espe cially two dimensional X ray diffraction can be used to measure the structural information of a material library with high speed and high accu racy The D8 DISCOVER with GADDS for Combina torial Chemistry is designed for the rapid screening of combinatorial libraries The system design is based on two dimensional X ray dif fraction XRD theory A two dimensional multi wire area detector can collect a large area of a diffraction pattern with high speed high sensitiv ity low noise and in a real time mode A 2D dif fraction pattern contains information about the structure quantitative phase contents crystal orientation and deformation The laser video system ensures that each sample is aligned accurately on the instrument center The X ray beam is collimated to various sizes from 1000 to 50 um The vertical theta theta geometry and horizontally mounted XYZ stage allow one to load the combinatorial library with ease even for loose powders or liquids The GADDS software helps to select and save a record of the screen ing area and steps The diffraction results are processed and mapped to the screening grid ba
173. icles larger than 1 um LaBg contributes less than 0 01 FWHM due to size broadening This sample should be measured on the GADDS system with the fol lowing instrument parameters Radiation Cu Sample to detector distance 30cm Collimator 0 2 mm kV Ma 40 40 At least 1 hr As necessary Data collection time Sample rotation Sample oscillation As necessary As previously discussed the and 20 values should be selected appropriately Measurement conditions for the standard and unknown must be identical If crystallite size measurements are made in transmission it is important to match the thickness of the sample and the standard M86 E01007 Crystal Size GADDS User Manual 7 5 References 1 G Allegra and S Brickner Crystallite Size Dis tributions and Diffraction Line Profiles Near the Peak Maximum Powder Diffr 8 2 102 106 1993 R Delhez Th H de Keijser and E J Mitte meijer Determination of Crystallite Size and Lat tice Distortions through X ray Diffraction Analysis Recipes Methods and Comments Fresenius Z Anal Chem 312 1 16 1982 L Dengfa and W Yuming The Hook Effect of X ray Diffraction Peak Broadening of Multilayer Thin Films Powder Diffr 2 3 180 182 1987 H Ebel Crystallite Size Distributions from Inten sities of Diffraction Spots Powder Diffr 3 3 168 171 1988 H P Klug and L E Alexander X ray Diffracti
174. iffraction cone distortion at the particular y 20 position Table 6 1 Equations for Calculation of Strain Coefficients fj Strain fa fi f22 fi3 fog fas Coefficients hy 2hyh ho 2h4h 2hsh h3 a sin 0 cos o sin y cos 0 sin o b cos y cos 0 c sin 0 sin o sin y cos 0 cos o h4 acoso b cos y sin c sin y sin h asin b cos y cos c sin y cos p h3 b sin y c cos y In GADDS x is used instead of y so use y 90 yg in the equation Use o vy and p angles in the equation even if the rotation is not available For example for fixed chi holder use yg 54 74 or y 35 26 in the equation for XYZ stage v or rotation are not available use 0 in the equation Mg hafa are components of the unit vector of the diffraction vector H pg expressed in the sample coordinates Equation 6 2 is the funda mental equation for strain and stress measure ment by diffraction using 2D detectors which gives a direct relation between the diffraction cone distortion and strain tensor Since it is a lin ear equation with six unknowns in principle the strain tensor can be solved with six y 20 data points The least squares method can be used to solve the strain or stress tensor with very high M86 E01007 Residual Stress GADDS User Manual accuracy and low statistics error For isotropic materials there are only two independent elas tic constan
175. ine Focus The projection of the focal spot perpendicu lar to the focal spot length with a takeoff angle is line focus The line focus is com monly used for conventional diffractometer with point detector or PSD M86 E01007 GADDS User Manual Nomenclature and Glossary Line Geometry The geometry configuration or X ray optics for an X ray diffraction system using line focus X ray beam commonly associated with a point detector or PSD Microdiffraction Diffraction applications with small sample or small micro area on a sample The X ray beam size used for microdiffraction is in the range from a few hundred microns down to microns or sub microns Monocapillary A glass tube used for collimating X ray beam by total external reflection Monochromatic Consisting of radiation of a single wave length or of a very small range of wave lengths Monochromator A device used to select radiation of a single wavelength by use of diffraction from an appropriate crystal such as a graphite crys tal Parallel Beam All rays of an X ray beam travel in the same direction within a limited cross section size The cross section size of the X ray beam does not change with distance Parallel Optics An X ray optical device which delivers a parallel X ray beam such as collimator and G bel mirror Parasitic Scattering The scattering picked up by the detector from the region around the direct beam caused by p
176. inhole scattering Percent Crystallinity The ratio of integrated X ray diffraction intensity from the crystalline peaks to the sum of the crystalline and amorphous inten sity Point Detector A detector used to measure the diffracted X ray intensity one specific angle at one time The data collected at one time is treated as one point in the diffraction pattern The typi cal point detectors are scintillation counters proportional counters and semiconductor detectors It can also be called OD zero dimensional detector Point Geometry The geometry configuration or X ray optics for an X ray diffraction system using point focus X ray beam commonly associated with a 2D detector M86 E01007 Nomenclature and Glossary GADDS User Manual Pole Figure The stereographic projection of pole density space distribution of a polycrystalline sam ple Pole Image Similar or identical to pole figure but not necessarily a stereographic projection Pole Sphere Spherical representation of pole density space distribution Powder Diffraction Diffraction by a crystalline powder or a polycrystalline sample The diffraction pat tern consists of lines or rings rather than separate diffraction spots PSD Position Sensitive Detector Commonly 1D linear PSD RAG Rotating anode generator Reflection Since diffraction by a crystal may be consid ered as reflection from a lattice plane this term is also
177. ion is about 0 3 to 0 4 mm Thus for applications such as tex ture or phase identification from a bulk pow dered specimen which ordinarily employ collimators larger than 0 4 mm there is no ben efit to using G bel mirrors In fact the low diver gence of the resulting beam can cause poor statistical grain sampling in such cases Table 2 24 Specifications of the single G bel mirror and the cross coupled G bel mirrors Intensity Ratio mirrors monochromator Goniometer D500X D8 GADDS SMART Beam parallel parallel parallel Focus line focus line focus point focus Dimension 40x20 40x200r 40x20 60x20 mm 60x20 No o X Experiment gt d spacing 31 38 31 38 31 38 40 50 Range A lt Radiation Cu Co Cr Cu Co Cr Cu Cu a oe 93 8 8 Approximate 2 5x 2 5x 2 5x 2 0x 20y Cu Angle of 0 6x 0 6x 0 6x 1x Acceptance Collimator Pinhole Size mm Beam 0 05 0 05 0 05 0 05 Divergence 0 07x 0 07x 0 07x 0 07x Figure 2 8 Comparison of X ray intensity between cross Max Beam gt 0 5 gt 0 5 20 5 20 5 coupled G bel mirrors and monochromator for various Size mm collimator pinhole size The solid line represents experimental value and the broken line is the computer Monochro Ka Ka Ka Ka matization simulated values M86 E01007 GADDS User Manual System Configuration 2 2 5 Monocapillary The monocapillary is a c
178. ions In some cases only a small section of the pole figure is necessary to represent the necessary sample orientation information Other widely used partial pole figure representations include rocking curves and fiber texture plots A rocking curve o scan is the simplest check for orienta tion In single crystal work it is a way to check for crystal quality if only one orientation exists If more than one orientation exists then two or more crystals exist with different orientations for that specific reciprocal lattice plane In general rocking curves give a good relative comparison of texture strength The full width at half maxi mum FWHM of the fiber texture plot quantifies the pole spread with a larger FWHM indicating a weaker more random texture Two other methods used to characterize orientation mostly in the polymer field and are related to direction cosines of intensity weighted pole figures The functions are described by the Hermans and the White Spruiell orientation indices 5 6 Using POLE FIGURE SCHEME to Plan Strategy and Coverage Sample shadowing is one of the difficulties that can be overcome using POLE_FIGURE SCHEME For a given set of data collection con ditions the simulated pole figure can have a central hole in reflection mode or the poles missing in transmission mode To fill in this missing polar data which is caused by the a p angles not being in the diffracting condition or the reflections not bein
179. ions Using characteristic radiation sev eral reflection centroids can be determined with out a goniometer and the orientation can be determined based on a known unit cell Usually the sample must have a specific orientation within set tolerances The measured diffraction pattern and orientation information obtained is compared to theoretical values or standard pat terns Diffraction analysis software usually inter acts with the production line in an accept or reject mode For single crystal thin films on single crystal sub strates an area detector can provide a view of reciprocal space in a short period of time Sin gle crystal analysis techniques can then be used to determine orientation matrices for both the film s and substrate The resulting orienta tion matrices provide the information necessary to determine the angle between any sample direction and a crystallographic direction This type of an analysis is faster and more descrip tive than pole figures for single crystal films on single crystal substrates In addition if both the orientation matrix of the film and the substrate are determined the relationship between the two cells can also be determined This type of single crystal analysis is relatively advanced A simpler though less powerful approach is avail able using CURSOR commands M86 E01007 Texture GADDS User Manual 5 12 Semiquantitative Analysis with CURSOR Commands CURSOR CIRCLE is useful
180. is normally stored as intensity values on a 1024x1024 pixel grid or a 512x512 pixel grid incident beam Figure 1 5 A diffraction cone and the conic section with a 2D detector plane M86 E01007 GADDS User Manual Introduction and Overview 1 3 2 Diffraction Cones and Laboratory Axes Figure 1 6 describes the geometric definition of diffraction cones in the laboratory coordinates system X Y_Z Figure 1 6 The geometric definition of diffraction rings in laboratory axes GADDS uses the same diffraction geometry conventions as the conventional 3 circle goni ometer which is consistent with the Bruker AXS P3 and P4 diffractometers In these conven tions the direct X ray beam propagates along the X axis Z is up and Y makes up a right handed rectangular coordinate system The axis X is also the rotation axis of the cones The apex angles of the cones are determined by the 20 values given by the Bragg equation The apex angels are twice the 20 values for forward reflection 20 lt 90 and twice the values of 180 20 for backward reflection 20 gt 90 The y angle is the azimuthal angle from the origin at the 6 o clock direction Z direction with a right handed rotation axis along the opposite direc tion of the incident beam X direction The y angle here is used to define the direction of the diffracted beam on the cone In the past y was used to denote this angle it was changed
181. ishes the task for you Thus it is convenient and accurate to think of a script as a means for automating operation of the diffractometer or frame processing from a higher level Some typical uses of scripts are to e Automate repetitive tasks commands via a single command e Process samples in batch mode without user intervention e Simplify menu input by hiding unneeded entries e Customize the menu bar with user task commands e Create demo loops for presentations Scripts are comprised of one or more script files which are simply ASCII files that contain a list of commands where each command is executed in sequential order That is GADDS simply starts at the beginning of the script file and pro ceeds one line at a time until it reaches the end at which point it stops You can create script files in two ways using the auto script recorder or a text editor The auto script recorder can help you get started creating scripts After you ve assigned a script to a user task running the script is as simple as clicking the menu item M86 E01007 Script Files GADDS User Manual Bruker AXS script files are sometimes called SLAM files for Scripting Lexical Analyzer and Monitor By convention Bruker AXS script files have the extension slm Wherever GADDS asks for the name of a script file the slm exten sion is assumed unless you specifically give a different extension For examples of script
182. ision limit Manually drive w position of the sample stage to the minimum and maximum o angles for all the samples on the stage to ensure no collision between the sample stage and the detector and the laser video microscope All selected mea surement positions should be tested if XYZ stage is used for multiple sample or stress map ping The and v rotations should also be checked if the fixed chi stage the two position stage or the circle stage is used for and y scans during data collection 3 Data collection Data collection functions such as SingleRun MultiRun and MultiTarget are all suitable for stress data collection 4 Unwarp frames Unwarp the data frame before stress evaluation if this step is not performed automatically 5 LPA correction and absorption correction optional The LPA Lorentz polarization air faceplate absorption and sample absorption correction can also be performed before stress evaluation It is however not necessary for most cases Experiments shows that the correction contrib utes less than 1 variation in the final stress values M86 E01007 GADDS User Manual Residual Stress 6 2 Stress Evaluation Using One Dimensional Data Conventional Method For GADDS software version 3 323 or later the conventional stress function is added under the Analyze menu First follow these steps to pro cess the data in GADDS 1 Load or open the first frame For example
183. ith the HI STAR area detector The frame is collected on a steel roller at 123 A total of 7 frames were collected at angles from 33 to 123 A total of 9 profiles can be obtained from each frame by y integration over Ay intervals of 5 The data points at 4 90 from 7 frames a typi cal data set for an Q diffractometer are used to calculate stress with the conventional sin w method For the 2D method in order to compare the statistical error between different numbers of data points the stress is calculated 3 5 7 and 9 data points on each frame The results from Stress Test 07 22 97 09 34 22 Created 03 05 97 Mag Quad 1 0 Omega 123 00 width 0000 Counts 4358113 30 Time s 1800 0 Distance 14 920 27 Size 1024 25 2th begi 150 00 2th en 159 00 22 chi begi 67 500 chi en 112 50 20 chi step 5 degree 17 chi from to 70 67 5 72 5 75 72 5 77 5 80 77 5 82 5 85 82 5 87 5 90 87 5 92 5 95 92 5 97 5 100 97 55 102 5 105 1025 107 5 110 107 5 112 5 the conventional method and the new 2D method are summarized in Table 6 4 and com pared in Figure 6 26 The measured residual stress is compressive and the stress values from different methods agree very well With the data taken from the same measurement 7 frames the new method gives lower statistical error and the error decreases with increasing number of data points from the diffraction ring M86 E01007 GADDS User Manual Residual Stress Table 6 4
184. itional expression evaluates to true the block of commands after the IF statement is exe cuted and all ELSEIF and ELSE com mand blocks are ignored When conditional is false the next ELSEIF statement is treated as an IF statement When all con ditionals are false the block of commands after the ELSE statement is executed Nesting of multiple IF statements is not allowed WHILE conditional DO NEXT WEND Define a block of commands to be exe cuted possibly repeatedly whenever the conditional evaluates to true When WEND is reached control returns to the WHILE statement and the conditional is re evalu ated When conditional is false control con tinues after the WEND statement Thus the WHILE block of commands is repeatedly executed until either the conditional becomes false or an error occurs In version 4 1 16 NEXT forces a jump back to the WHILE statement Use LET WHILE and INC statements to emulate a for loop as in LET N 1 WHILE N lt 12 DO command block executed 12 times INC N WEND Use NEXT to skip subsequent commands inside a WHILE block as in LET N 1 WHILE N lt 12 DO INC N command block executed 12 times IF clause THEN NEXT ENDIF more commands may or may not get executed WEND 10 26 M86 E01007 GADDS User Manual Script Files conditional Conditional expressions must be in the form TRUE FALSE
185. ject GADDS 4 users only Place the PROJECT command here Step 2 collect the frames and unwarp Place all SCAN commands here Step 3 integrate each frame into a raw range Place all LOAD amp INTEGRATE commands here Step 4 merge multi range raw file into single range raw file Place the SYSTEM command here Step 5 spawn EVA and perform a search match operation n y i see your EVA manual on how to do this 14 Check for omissions within the script file and enter the appropriate syntax for any missing commands Only the last command to spawn EVA is missing from our script As there are many version of EVA will leave this command to the user to determine see your DIFFRAC S EVA manual 10 12 M86 E01007 GADDS User Manual Script Files 15 Check for errors or unwanted features in the script file such as expanded logical names or non echoed information For instance in the PROJECT NEW com mand the working directory s value was expanded from the logical name of PROJECT Change it back to read PROJECT NEW CNAME Corundum 0 TITLE Corundum Test Sample amp WORKDIR S PROJECT FORMULA MORPH CCOL DENSITY amp DENSMETH CLEAR RESET In the MERGE utility the inputs were not echoed to the script file This is typical of spawned utilities or programs Refer to the Merge section of the GADDS Software Ref erence Manual or the SLAM Appendix for the complete command line syntax
186. l mirrors can offer greater intensity than conventional optics The low divergence of the beam incident on the sample from G bel mirrors also decreases the width of crystalline peaks improving the resolu tion of a GADDS system The G bel mirror is a parabolic shaped multi layer mirror Multilayer mirrors reflect X rays in the same way as Bragg diffraction from crystals so multilayer mirrors can be used as a mono chromator In contrast to a conventional crystal monochromator G bel mirrors are manufac tured so that the d spacing between the layers varies in a controlled manner The appropriate gradient in the d spacing depends on factors which include wavelength the location of the mirror with respect to the source and the appli cation for which the mirror is designed Figure 2 7 a illustrates a single G bel mirror The G bel mirror is parabolically bent which causes a divergent beam striking the mirror at different locations and angles to yield an intense and highly parallel beam With Bragg diffraction the radiation is monochromatized to K while Kg and Bremsstrahlung are suppressed The single mirror can be used with either a point focus or line focus tube In Bruker UBC univer sal beam concept optics a single mirror is cou pled with a line focus tube The combination allows an easy switch between line focus geom etry and point focus geometry without changing the X ray tube When these optics are on a GADDS syst
187. le collimator or monocapillary The multiwire detector has a pixel resolution of 100 um or 200 um witha frame size of 1024x1024 or 512x512 The detector can be set at a sample to detector dis tance between 6 cm to 30 cm depending on the application For larger angular coverage ata short distance 65 measuring range at 6 cm or high angular resolution at a long distance 0 02 resolution at 30 cm M86 E01007 System Configuration GADDS User Manual 2 8 2 Transmission Mode Screening In an XRD system the diffracted X rays are measured simultaneously in a 2D range so no slit or scanning step can be used to control the instrument broadening The beam spread over the sample surface can not be focused back to the detector Figure 2 23 shows geometry of 2D diffraction in reflection mode a and transmis sion mode b Defocusing effect is observed with low incident angle over a flat sample sur face in reflection mode diffraction In reflection mode the diffracted beam in low 26 angle is narrower than the diffracted beam in high 20 angle In transmission mode with the incident beam perpendicular to the sample surface no such defocusing effect is observed incident beam sa mp la a Figure 2 23 Geometry of XRD a reflection mode b transmission mode M86 E01007 GADDS User Manual System Configuration If one looks at the cross section on the diffracto meter plane and forward diffraction 2
188. le should look like PROJECT NEW CNAME Corundum 0 TITLE Corundum Test Sample amp WORKDIR D frames Corundum0 FORMULA MORPH CCOL DENSITY amp DENSMETH CLEAR RESET SCAN SINGLERU WIDTH 10 0 SCANTI SAMPLE Corundum NU DISPLAY 16 REALTI SCAN SINGLERU WIDTH 10 0 SCANTI SAMPLE Corundum NU DISPLAY 16 REALTI SCAN SINGLERU WIDTH 10 0 SCANTI SAMPLE Corundum NU DISPLAY 16 REALTI SCAN SINGLERU WIDTH 10 0 SCANTI SAMPLE Corundum NU DISPLAY 16 REALTI corund0 001 DISPLAY 63 SCAL LOAD OAD HH eH SCALE 1 0 LOAD INTEGRATE C TEGRATE W corundO0 TEGRATE C TEGRATE W corundO0 INTEGRATE C GI DH Gl E CLEAR MOD E 1 00 00 TI iral CLEAR MOD iz E CLEAR MOD HI 3 000 359000 120 0 RITE STITLE FILENAME 002 DISPLAY 63 SCAL HI 30 000 60 000 115 RITE STITLE FILENAME 003 DISPLAY 63 SCAL HI 55 000 82 000 II5 SCALE 1 0 LOAD SCALE 1 0 SYSTE INTEGRATE W corundO0 INTEGRATE C INTEGRATE W RITE TITLE FILENAME 004 DISPLAY 63 SCAL HI 80 000 110 000 115 RITE TITLE FILENAME GADDSSSYSTEM merge E Scan 1 2THETA 70 0 OMEGA 30 0 P 1 2THETA 20 0 OMEGA 5 0 PHI 0 0 CHI 54 74 AXIS 2 amp 1 00 00 TITLE Corundum Test Sample amp SAMPLE 0 NAME corund RUN 0 FRAMENO 001 amp CLEAR MODE Scan 1 2THETA 45 0 OMEGA 17 5 0 PHI 0
189. low rate clean water and filter 1 2 Make sure all the safety interlocks work properly and are set correctly 1 3 Set the key switch to position I Posi tion Il is reserved for qualified service personnel so you should not operate the generator on this setting M86 E01007 GADDS User Manual System Configuration 2 Start the generator 3 2 When increasing the generator power 2 1 Press the Heater key for approximately manually alwayeincraase voltage het and then current When reducing the 2 seconds and wait until the LED in the Heater key lights continuously generator power always reduce the current first and then voltage a Jhen press the ON Key Ane aaa 3 3 When using a new X ray tube or when ON signal lamp and radiation warning the generator has been shut down for lamps light the LED in the Heater key more then 12 hours observe the follow goes off the LED in the ON key lights ing start up procedures Table 2 5 And the display values read kV 20 i unless suggested otherwise by the mA 5 See the Operating Instructions manufacturer An automatic start up if the generator responds differently routine can be selected for new tubes 3 Adjust the voltage and current see Operating Instructions 3 1 You can adjust the voltage and current 3 4 To increase the lifetime of X ray tubes manually for PLATFORM GADDS or set the generator to standby mode through
190. lt 30 between pixels If these conditions are not met add to the col lected frame After collecting a satisfactory frame unwarp the frame and smooth it using CONVOLVE 2 Save this processed frame M86 E01007 Percent Crystallinity GADDS User Manual Figure 8 5 A Nylon fiber frame with air scatter removed B smoothed Nylon fiber frame with air scatter removed C amorphous scatter from PERCENT_CRYSTAL FULL D crystalline scatter difference frame of A and C 8 8 M86 E01007 GADDS User Manual Percent Crystallinity Enter PERCENT_CRYSTAL FULL and start with the defaults to see what part of the crystalline pattern appears The radius and height parameters affect the shape of the sliding ellipsoid used to char acterize the non crystalline scatter The smaller the radius parameter the closer the background surface follows the frame image The height parameter affects the shape of the sliding ellipsoid A height of zero obtains a disk A height equal to the radius parameter produces a sphere Adjust the pattern as appropriate If the crystalline peaks are sharp increase the height parameter If no crystalline features appear on the frame with the default values decrease the radius parameter until a crystalline pattern is observed Then increase the radius until the resultant pattern is free of the crystalline scatter The initial radius can be determined with the vector cursor Set the curs
191. m in diameter For quantitative analysis texture or percent crystallinity measurements 0 5 mm or 0 8 mm collimators are typically used In the case of quantitative analysis and texture measurements using too small a collimator can actually be a detriment causing poor statistical grain sampling In such cases you can improve statistics by oscillating the sample Crystallite size measurements are usually measured with a 0 2 mm collimator at 30 cm sample to detector distance The choice of collimator size is often a trade off between intensity and the ability to illu minate small regions or to resolve closely spaced lines The smaller the collimator the lower the photon flux that strikes the sample and the longer the count time to acquire statisti cally significant data 2 2 3 Sample to Detector Distance and Angular Resolution The divergence of the X ray beam is a function of collimator size sample to detector distance and 20 The tables that follow can be used to determine a suitable collimator size and sample to detector distance to resolve closely spaced peaks In all cases the standard two pinhole collimators are assumed which have a sample to front pinhole distance of 8 mm Only the more common combinations of collimator sizes and sample to detector distances are tabulated These tables are for reflection mode Transmis sion mode values for the apparent beam size can be located by translating by 90 o 90
192. mand Collect Detector Fe Bias to set the Fe settings For other radiation turn the bias switch to Fe settings as marked on M86 E01007 Basic System Operation GADDS User Manual the PDC Note that the lowest field on the right is set to Fe Bias 3 Left click Collect gt Goniometer gt Drive The Goniometer Drive options window will appear see Figure 3 3 Options for Collect Goniometer Drive X Figure 3 3 Options for Collect Goniometer Drive window M86 E01007 GADDS User Manual Basic System Operation 4 Enter values in the first and second line to drive the detector out of the primary beam Consult Table 3 1 for appropriate goniome ter and generator settings for 2 theta and omega Sample to detector Detector and Fe foil Generator power for 0 5 distance assembly rotation angle and 0 8 mm collimator 6 cm 50 40kV 5mA 10cm 50 40kV 10mA 15cm 45 40kV 10mA 20 cm 40 40kV 15mA 25 cm 30 40kV 20mA 30 cm 20 40kV 20mA 35 cm 15 40kV 25mA Table 3 1 Recommended angle and generator power for the amorphous Fe foil calibration NOTE For theta theta systems set theta1 tube to the angle in Table 3 1 and theta2 detector to zero M86 E01007 Basic System Operation GADDS User Manual 3 4 1 Flood Field Correction The correction filename and additional related information display in the lower right corner of the GADDS window Note that the 1 Left
193. mined 206 use 156 for most steels This value is used to calculate y tilt M86 E01007 Residual Stress GADDS User Manual Title Title to use the frame title or input other title File name The processed data will be saved in DIFFRAC format into this filename raw for all y angles 201 200 x1 x defines the integrated region 204 and 205 determine the background of the profiles x4 and x determine the integrated region along the diffraction ring Normally use ADDS General Area Detector Diffraction System V4 A 02 Copyr 1997 98 Bruker fe Edt Coen Poc 02 25 99 Created Mag Quad Omega width Counts Time s Distance Size 2th begi 2th end chi begi chi en Distance FloodFld Spatial 1024x1024 1 2 3 4 Select edge M Move ENTER L button Integrate ESC O buttons Quit Stress on Almen Strip HRC 55 frames strsnorm 000 Ay 5 to 10 degrees i e integrate over the x range of 85 95 or 80 100 3 Click OK to start processing You can rede fine 201 205 x1 X2 using the mouse for each frame After you have defined the inte grated region click the mouse on the region to process the data see Figure 6 14 10 03 01 07 29 98 1 0 12 000 LINEAR LINEAR No PDC Figure 6 14 The y integration region on data frame M86 E01007 GADDS User Manual Residual Stress After the above steps GADDS saves the pro cessed data in DIFFRAC format
194. mmand as the last command of the script particularly for scripts called as user tasks Several example scripts are provided in your system The scripts are stored in the GADDSS TEST directory and are used as part of the demo loop To execute this demo routine on the frame buffer PC GADDSSTEST gadds You can also start a script execution that uses replaceable parameter see section 10 4 For example to start a script that takes four replace able parameters the first is the filename the second is the sample title the third is the sam ple name and the fourth is the scan time would look something like PhaseID cor My sample Corundum 60 00 M86 E01007 GADDS User Manual Script Files 10 3 Creating Script Files You can create and edit script files with any ASCII text editor such as NotePad under NT Word processors Write WordPad Word or WordPerfect do not work for creating script files GADDS also contains an automatic script generating function which logs each interac tively executed command as the equivalent SLAM command into a script file see the File gt ScriptFile command for more details To create your script file s you may either use the auto script generating facility an editor or both The example below uses both Problem Suppose you simply wish to identify the phases of a sample which is often called qualitative phase identification You need to collect several frames so that t
195. n stants used for stress measurement also expressed as 2S hkl if the aniso X tropic correction for a specific crystal line plane is considered One of the sample coordinates It is in Y the same direction as the sample trans lation axis X except the origin is fixed on sample One of the sample coordinates It is in the same direction as the sample trans lation axis Y except the origin is fixed on sample One of the sample coordinates It is in the same direction as the sample trans lation axis Z except the origin is fixed on sample One of the sample translation coordi nates with the origin on the instrument center X is in the opposite direction of the incident X ray beam when w 0 0 X normally lies on the sample surface One of the sample translation coordi nates with the origin on the instrument center Y normally lies on the sample surface angle and makes a 90 right handed angle from X One of the sample translation coordi nates with the origin on the instrument center Z is normally in the direction of the sample surface normal One of the laboratory coordinates X is in the direction of the incident X ray beam One of the laboratory coordinates Y lies in the diffractometer plane and makes up a right handed rectangular coordinate system with X and Z One of the laboratory coordinates Z is up from the center of instrument and perpendicular to the diffractometer plane M86 E01
196. n Time Enter scan time in seconds or as time string 4 Re start GADDS 10 22 M86 E01007 GADDS User Manual Script Files Example You wish to add the PhaselD script created in the previous section to the menu bar so only yourself can easily access the script The steps are 1 Create a directory for GADDS customiza tion files for your exclusive use C saxi GADDSSmith 2 Copy do not move the GADDS customiza tion files to the new directory These files are lut std and usertask ini 3 Use Start gt Settings gt Control Panel gt Sys tem to add or modify the GADDS SYS DATA environment variable in user space to point to the new directory 4 Modify the GADDS SYSDATA usertask ini file as in the previous example 10 6 Nesting Script Files You may create and execute nested script files which are a script file within another script file Some typical uses of nesting script files are to e Simplify the script file by replacing repeated sections with a nested script file e Simplify the script file by replacing similar sections with a nested script file that uses replaceable parameters e Create a subroutine procedure that may be called from several different script files e Reorder replaceable parameters e Modify concatenate passed replaceable parameters and pass new replaceable parameters to a nested script You start script files using the command By inserting an command
197. n before and during data collection GADDS uses three types of sample alignment systems optical microscope video microscope and laser video microscope systems The optical microscope allows you to directly observe the sample in a magnified image with a crosshair to determine the sample position Fig ure 2 11a The video microscope system includes a micro scope head with manual zoom a color CCD camera and a frame grabber to capture and display the image of the sample Figure 2 11b User selectable reticles are available in the video software You can set the crosshair posi tion and calibrate the image to determine the sample position and size Since the video image can be captured with the safety enclosure closed the video microscope can monitor the sample s state and position during the data col lection You can also save the image as a com puter image file a Optical microscope b Video microscope Figure 2 11 Sample alignment systems a optical microscope and b video microscope M86 E01007 System Configuration GADDS User Manual The laser video sample alignment system is based on a patent owned by Bruker AXS Inc The cross point of the laser beam and the opti cal axis of the zoom video are pre aligned to the instrument center Figure 2 12a The laser image spot falls on the center of the crosshair when the sample surface is positioned at the instrument
198. n the sample If you have to change X ray tubes see your GADDS Administrator and refer to the GADDS Administrator s Manual Mount the sample See also section 3 Use high resolution 1024x1024 mode Move the detector to the appropriate detec tor distance Make sure you can resolve all lines at that distance See also section 3 for calibration e Single frame Phase ID for quick qualitative results Multiframe Phase ID for better results especially reflection mode 5 Make sure you measure the lowest diffrac tion line available from the sample Note that in reflection geometry the smallest detectable reflection is at 20 beam stop 6 Setup a SingleRun measurement to collect at one or several detector and angles Make sure the 20 coverage for the different goniometer positions overlaps Best resolu tion is obtained close to 20 2m because of focusing effects in reflection and minimum absorption effects in transmission 7 Choose a collimator with a diameter that matches the sample dimensions Start the measurement and wait Load the first frame 10 Left click Peaks gt Integrate gt y integration see Figure 4 5 and select the region to be integrated the normalization mode 3 and an appropriate step width typically 05 Options for Peaks Integrate Chi xi 2theta Chi Start 20 00 deg Start 60 00 deg End 30 00 deg End ft 20 00 deg Normalize intensity 5 Bin normalized St
199. n y stage or with an adapter mount for the fixed x stage With this arrangement a meridional reflection up to 30 can be observed with either the fixed or two position x stages with the detector at 6 cm For the 4 cradle this restriction is removed by plac ing x 0 After setting the fiber axis vertical for both the two position and fixed y stage COL LECT GONIOMETER FIXED AXES should be used to set y 0 When this is done process ing the pole figure with PD 1 the fiber axis will be vertical on the pole figure diagram If the fiber is instead mounted at 54 74 the y value should not be updated If angles 30 must be col lected on the meridian the sample must be physically remounted so that the fiber axis is horizontal For those measurements x should be updated to 90 M86 E01007 GADDS User Manual Texture For equatorial reflections pole figure data is col lected in a single frame and processed using the POLE_FIGURE PROCESS FIBER option The resulting pole figure will show a rotationally sym metric data pattern Figure 5 9 shows a data frame and 200 pole figure from a bundle of Kevlar 149 fibers Figure 5 9 Data frame left and 200 pole figure right from Kevlar 149 fibers Meridional reflections are collected as follows 1 With the physical fiber axis vertical set 0 with COLLECT GONIOMETER UPDATE and set y 90 with COLLECT GONIOMETER FIXED AXES 2 In SCAN SIN
200. nalysis which may lead to undesirably long data collection times In addition many ODF programs have difficulty handling sharply tex tured materials which is the case with many electronic thin films Since most thin films have symmetrical fiber or near fiber texture in which the orientation distribution possesses rational symmetry about the substrate normal the tex ture strength can be quantitatively represented from a single pole figure as a Fiber Texture Plot FTP Figure 5 13 Intensity Tilt Angle a 0 20 40 60 80 Figure 5 13 Fiber texture plot of Al 5 26 M86 E01007 GADDS User Manual Texture The FTP is essentially a slice integration from the center a 0 to the outer edge a 90 of the pole figure An a 0 represents reciprocal lattice planes oriented parallel to the substrate while an a 90 represents reciprocal lattice planes oriented perpendicular to the substrate see Figure 5 14 In reality measurement of ori entation perpendicular to the substrate requires X ray diffraction in transmission rather than reflection so most FTP representations extend from a 0 to a 85 The example shows the Al 111 planes parallel to the Si 100 substrate s x Nrilm hkl L1 L1 L1 1 1 f 1 substrate 1 La qq d l Figure 5 14 Angle between the substrate normal and the normal to a given diffraction plane Np Since Al is cubic the angle between the 111 plane and
201. ntation Figure 6 2 a The diffraction cones from an unstressed polycrystalline sample and the diffraction cone distortion due to stresses b Sample orientation in terms of y and angles M86 E01007 Residual Stress GADDS User Manual Figure 6 2 b shows the sample orientation angles o v and 548585 are sample coordi nates with S4S5 on the sample surface plane and S5 as surface normal At o y 0 S is in the opposite direction of the incident X ray beam and S points up and overlaps with axis The o axis is fixed on the laboratory coor dinates is a rotation above a horizontal axis and 6 is a left hand sample rotation about its normal S5 y axis varies with rotation and axis varies with and v rotation y and xg have the same axis but different starting position and rotation direction and x j 90 y The surface of the area detector can be consid ered a plane intersecting with the diffraction cones Figure 6 3 shows the diffraction data col lected on the area detector o is the detector swing angle When imaged on axis a 0 the conic sections appear as circles When the detector is at off axis position a 0 the conic section may be an ellipse parabola or hyper bola For convenience all kinds of conic sec tions will be referred to as diffraction rings hereafter in this paper All diffraction rings col lected with a single exposure will be referred to as frames The
202. ntification Phase ID can be done by integration over a selected range of two theta 20 and chi x A direct link to the ICDD data base profile fitting with conventional peak shapes and fundamental parameters quantifi cation of phases and lattice parameter indexing and refinement make powder diffraction analy sis easy and fast Due to the integration along the Debye rings the integrated data gives better intensity and statistics for phase ID and quanti tative analysis especially for those samples with texture large grain size or small quantity Texture measurement using an area detector is extremely fast compared to the measurement using a scintillation counter or a linear position sensitive detector PSD The area detector col lects texture data and background values simul taneously for multiple poles and multiple directions Due to the high measurement speed GADDS can measure pole figures at very fine steps allowing detection of very sharp textures M86 E01007 Introduction and Overview GADDS User Manual GADDS is the best tool for quantitative texture analysis Stress measurement using the two dimensional area detector is based on a new 2D stress algo rithm developed by Bruker AXS which gives a direct relationship between the stress tensor and the diffraction cone distortion Since the whole or a part of the Debye ring is used for stress calculation GADDS can measure stress with high sensitivity high
203. nual 1 16 M86 E01007 GADDS User Manual System Configuration 2 System Configuration GADDS systems are available in a variety of configurations to fulfill requirements of different applications and samples A system normally consists of the following five major units each of which may have several options e an X ray generator to produce X rays e X ray optics to condition the primary X ray beam e a goniometer and sample stage to establish and manipulate the geometric relationship between primary beam sample and detec tor e asample alignment and monitor to assist users in positioning the sample into the instrument center and in monitoring the sample state and position e adetector HI STAR Area Detector System to intercept and record the scattering X rays from a sample and to save and display the diffraction pattern into a two dimensional image frame Figure 2 1 shows a typical system X ray Optics Me a e e d ej X ray Generator a Area Detector Sample Alignment Goniometer and Sample Stage and Monitor Figure 2 1 Five major units in a GADDS system X ray generator sealed tube X ray optics monochromator and collimator goniometer and sample stage sample alignment and monitor laser video and area detector M86 E01007 System Configuration GADDS User Manual In addition to the five major units there are other accessories such as a low t
204. o a rotating anode Ka1 and K 5 lines are so close in their wave generator RAG to synchrotron radiation with lengths that they are also called K doublet The CCD detector The sealed tube generator is the K line is about twice the intensity of Kyo If the most commonly used X ray source in the two K lines cannot be resolved they are simply GADDS system referred to as K line The wavelengths of char 2 1 2 X ray Spectrum and Characteristic acteristic lines are determined by the target Lines anode materials of the X ray generator Table 2 1 gives a list of common target materials and their wavelengths Table 2 2 lists typical applica tions for each target material X rays generated by sealed tubes or rotating anode generator have an X ray spectrum which presents intensity vs wavelength Figure 2 2 Table 2 1 Wavelengths of characteristic lines of common target elements dis Target Energy Wavelength A 10 1 nm Ka keV Ka Kal Ka2 Kb 2 Kg Ag 22 11 0 560868 0 5594075 0 563789 0 497069 E E Mo 17 44 0 710730 0 709300 0 713590 0 632288 Cu 8 04 1 541838 1 540562 1 544390 1 392218 Co 6 93 1 790260 1 788965 1 792850 1 62079 E ah Fe e40 1 037356 1 936042 1 939980 1 75661 a b Cr 5 41 2 29100 2 28970 2 293606 2 08487 Figure 2 2 X ray spectrum generated by a sealed X ray tube or rotating anode generator showing a continuous M86
205. o be analyzed without any movement of the sample and detector This results in a huge speed advantage over conventional sys tems See the comparison between point posi tion sensitive and area detector in Figure 4 1 M86 E01007 Phase ID GADDS User Manual scintillation detector 1 l m small spot measured m scan necessary m long measuring time m large 20 range measured simultaneously medium measuring time Figure 4 1 Comparison between a point position sensitive and area detector large 20 and chi range measured simultaneously measurement of oriented samples m very short measuring times intensity versus 20 by integration ofthe data M86 E01007 GADDS User Manual Phase ID The GADDS software allows easy integration of the 2D diffraction data into intensity versus 20 plots This enables the collection of powder pat terns even from large grained and textured sam ples without losing information See Figures 4 2a through 4 2c Figure 4 2 From a large grained and textured sample M86 E01007 4 3 Phase ID GADDS User Manual The schematic intensity I versus 20 plots show the results of a point detector scan through a dif fraction pattern which is shown in the upper right corner of each plot The red arrow indi cates the scanning direction of the point detec tor Due to the non isotropic sample structure large grains and texture the intensity
206. o describe the orientation of a sample in the diffractometer The three angles are omega xg goniometer chi and phi Since the y symbol has been used for the azimuthal angle on the diffraction cones in this manual we use x to represent the y rotation in the 3 and 4 circle goniometer Figure 1 7 a shows the relationship between rotation axes o xg gt and the laboratory system X Yi Z is defined as a right handed rotation about Z axis The o axis is fixed on the laboratory coor dinates y is a left handed rotation about a hor izontal axis The yg axis makes an angle of with X axis in the X Yj plane when c0 The Xg axis lies on X when o is set at zero is a left handed rotation The axis overlaps with the Z axis when xg 0 The axis is away from the Z axis by x rotation for any nonzero x angle Figure 1 7 Sample rotation and translation in the laboratory system a Relationship between rotation axes and X Y 2 coordinates b Relationship among rotation axes Xg Ws 4 and translation axes XYZ Figure 1 7 b shows the relationship among all rotation axes o xo v gt and translation axes XYZ o is the base rotation all other rotations and translations are on top of this rotation The next rotation above c is the yg rotation y is also a rotation above a horizontal axis y and x have the same axis but different starting posi tions and rotation directions and xg 90 y In orde
207. o minimize effort For data consistency all frames on the same well must have the same acquisition time M86 E01007 GADDS User Manual Automation Example 11 2 Pre scan File 96WellsCollect slm Collect targets in a 96 well library Assumes GADDS CST system T2 Assumes distance 25 cm runbase 36 runchar 3 or this will fail Assumes Target list already defined with run numbers A01 to H12 jobname base of filename Scan time 1 00 in minutes or seconds 60 title S FILE filename sample name plate id sample number barcode o oe N Il o oP oe CO 0 I first collect all frames on all targets on error then continue Targets A01 to H12 let SN 01 while SN lt 96 do Drive to next target and quick screen pre scan for diffraction statistics scan multitargets 1 thetal 2 5 amp theta2 2 5 1 scantime 1 axis 2 amp width 10 title 3 sample 4 amp numsample 5 clear startrun N amp endrun N mode scan amp oscillate XY amplitude 1 Skip weak diffractor 25 cps is background Also prevents divide by Lh zeros IF GC 1000 THEN echo Skipping WELL diffraction is too weak Collect for 500 000 counts on first frame low 2T frame ELSE Calculate count time needed for 500 000 counts LET T 500000 GC Collect 1st frame 2T 0 Omega 5 to 5 for T2 systems scan singlerun 1 the
208. o or unchecked entry Some parameters and valued qualifiers may use special variables as their value These are 1 which refers to the current value of the 20 axis Q2 for o 3 for 6 4 for y 5 for X 6 for Y 7 for Z and 8 for zoom Release 4 0 14 added 9 for delta axis Also all param eter and valued qualifiers can take replaceable parameters 1 to 0 for their value or partial value as will be discussed later in section 10 3 Release 4 0 14 adds both replaceable variables 96A to Z see section 10 7 and new special variables P for project name Q for folder Q F for filename J for jooname R for frame run and QN for frame number which refer to the currently loaded frame Release 4 1 13 adds additional special variables A for anode Cu Q C for total counts D for description project name S for seconds T for title 1st line W for wavelength Kavg which refer to the currently loaded frame While special variables cannot be used in flow control statements all variables and replaceable parameters may be used in any SLAM command In release 4 1 13 all special variables can now be used in flow control statements Each SLAM command consists of one or more SLAM lines in the script file SLAM lines are lim ited to 512 characters and SLAM commands are limited to 1024 characters You can continue a long SLAM command on the next line by placing an ampersand at the end of the line for exam ple DISPL
209. o the surface 3 6 2 Goniometer Head m YLID Crystal Sample Mounting Screw ad x Z Axis Lock Z Axis Adjustment Y Axis Lock Y Axis Adjustment X Axis n Adjustment X Axis Lock Figure 3 13 Goniometer head showing X Y and Z adjustments Samples mounted on a goniometer head see Figure 3 13 can be used in either reflection or transmission mode Transmission samples must be centered to the goniometer center while reflection samples must have the sample sur face touching the goniometer center For transmission samples The procedure for mounting and aligning samples on the goniome ter head is 1 Mount the sample to the goniometer head and then attach the assembly to the goni ometer M86 E01007 Basic System Operation GADDS User Manual Start GADDS online version for your partic ular stage Collect gt Goniometer gt Optical command and verify the base angles are correct Base Angles Values 2 THETA 0 or 60 or some out of the way position so that microscope is easily accessed OMEGA D8 variable usually about 30 330 PLATFORM 30 330 Aztalan 90 270 P4 0 or 330 345 with LT D8 0 PLATFORM 0 Aztalan 0 P4 30 D8 PLATFORM 54 74 or 54 74 Azta lan 45 P4 330 Typically one uses the fixed chi value on systems with a chi axis Using the manual control box Phoenix Press SHIFT F1 1 then ENTER
210. of this angle on the 2D pole figure is the radial distance from the outer circle of the pole figure Alpha in GADDS soft ware Omax The maximum angular resolution of a SAXS system M86 E01007 Nomenclature and Glossary GADDS User Manual Ay AX Ej 209 20 The azimuthal angle between the pole direction and a reference direction The stereographic projection of the angle on the 2D pole figure is the angle from 3 o clock position in the counterclockwise direction Beta in GADDS software The maximum divergency angle of the X ray collimation The angle symbol reserved to replace y in the future document except xg The nomenclature x Ax x4 and yo may appear as y Ay y1 and Yo in some future documents Virtual oscillation angle for stress mea surement using the 2D detector y integration range The strain tensor with six components 15 12 22 13 23 33 The Bragg angle The angle between incident X ray beam or reflected beam and the reflecting crystal plane Com monly denoted as 20 2 Theta in GADDS software The unstressed Bragg angle normally used for stress measurement to repre sent 20 value without stress The lower 20 boundary of 20 or x integration range 2th begi in GADDS software 205 20p X1 The higher 20 boundary of 20 or y integration range 2th end in GADDS software The detector swing angle to define the angle between dete
211. of screws is present on the beam stop for this alignment Another air scatter effect arises from inci dent beam scattering which is a function of the sample geometry The best approach is to reduce this effect by putting the sample as close to the incident beam as possible and use a beam that is smaller than the sample This practice eliminates the shadow on the detector which is absorption of the air scatter before the sample Compton incoherent scattering contributes to the diffuse background in an X ray diffraction pattern in a way that can be modeled M86 E01007 Percent Crystallinity GADDS User Manual 8 2 Data Evaluation for Two Dimensional Data 8 2 1 Methods Supporting Percent Crystallinity Four methods that support percent crystallinity calculation are available with GADDS These are Compton Internal External and Full Exter nal and internal methods employ user specified areas of frame data for a relative measurement of percent crystallinity Thus the value obtained is not absolute The same is true of the PERCENT CRYSTAL FULL method Compton Method PERCENT CRYSTAL COMPTON Compton scattering can make a substantial con tribution to the background intensity If it is not corrected for the percent crystallinity value can be artificially low especially for polymeric mate rials For further discussion see Alexander 1985 Compton scattering can be modeled and removed in both the internal
212. ol lection is automatically scanned over all of the cells in the material library Selection of screen ing parameters includes integrated intensity maximum intensity peak width FWHM peak 20 position crystallinity internal external and full and various stress components The screening results can be displayed in a color coded map 3D surface plot or pass fail map with user defined criteria as is shown in Figure 2 31 Figure 2 30 2D frames and integrated diffraction profiles each from a single library point M86 E01007 System Configuration GADDS User Manual Figure 2 31 The screening parameters are displayed in color scale 3D surface plot or pass fail plot on the material library map 2 60 M86 E01007 GADDS User Manual Basic System Operation 3 Basic System Operation This section covers the procedures used in basic system operation of the D8 DISCOVER with GADDS including steps for turning on the system choosing the detector position collect ing detector correction files calibrating the sys tem positioning the sample and collecting data All functions used in this section are described in detail in the GADDS Software Reference Manual or in hardware manuals delivered for hardware components of the diffractometer It is assumed that the system is installed and aligned according to Bruker AXS standards M8
213. ole figure M86 E01007 GADDS User Manual Texture Figure 5 3 shows a 3D represented pole figure of a highly oriented thin film Two distinct orien tations are observed 90 and 45 with a weak third orientation normal to the surface Figure 5 3 Contours of oriented thin film M86 E01007 Texture GADDS User Manual C GADOS General Aves Detector Dillraction System V4 A 02 Copy 1397 38 Bruker Figure 5 4 Data processing M86 E01007 GADDS User Manual Texture 5 2 General Data Collection Considerations for Texture Analysis With the fixed y stage 842 050600 and two position y stage 842 050800 not all tilt angles a the angle between the incident beam and the sample normal are accessible With a fixed y stage complete pole figures to a 80 can only be collected for pole 20 38 With a two position x stage complete pole figures can only be collected for pole 20 lt 55 The 4 cradle 810 300500 can reach all tilt angles by adjust ing x appropriately The XYZ stage 842 050700 lacks and y motion so only the cen tral portion of the pole figure is observable With the XYZ stage the maximum a x0 in reflection mode only Figure 5 5 Effect of sample oscillation on a large grained aluminum specimen Data on the left is collected without sample oscillation data on the right is with sample oscillation M86 E01007 Texture GADDS User Manual
214. on Procedures for Polycrystalline and Amorphous Materials 2 4 ed John Wiley New York 1974 R C Reynolds Diffraction by Small and Disor dered Crystals In Reviews in Mineralogy Vol 20 Mineralogical Society of America Washing ton DC 1989 M86 E01007 GADDS User Manual Percent Crystallinity 8 Percent Crystallinity 8 1 Principle of Percent Crystallinity The crystallinity of a material influences many of its characteristics including mechanical strength opacity and thermal properties In practice crystallinity measurements are made both for research and development and for qual ity control X ray scattering occurs from both the crystalline and non crystalline material illumi nated with X rays The difference between the two types of scattering is in the ordering of the material Materials especially polymers have some amorphous contributions The ability to deconvolute the amorphous from the crystalline scattering is the key to obtaining a reliable num ber that is consistent with other techniques such as NMR and calorimetry M86 E01007 Percent Crystallinity GADDS User Manual Figure 8 1 A amorphous scattering B unoriented polycrystalline scattering C oriented polycrystalline and amorphous scattering As shown in Figure 8 1 X ray scattering from amorphous material produces a halo of inten sity which when integrated obtains a broad low intensity hump X
215. on for detailed requirements before collecting pole figure data For the mate rial of interest examine the Bravais lattice type on the PDF card If the reflections are indexed select the unique lines for the particular lattice For cubic tetragonal and hexagonal or rhom bohedral two lines are needed For monoclinic and orthorhombic three lines are required The trigonal case requires five pole figures due to an overlap of the hkl and khl reflections More lines may be required for the higher symmetry space groups if there is no sample symmetry For many sample symmetries it is unnecessary to collect pole figures covering 360 p since symmetry can be used to expand the collected data within the GADDS software using POLE FIGURE SYMMETRIZE and also within most ODF packages For an unknown system collecting the full pole figure is advisable The accuracy of an ODF series expansion depends on the number of terms in the series typically 16 The quality of the coefficients in the series depends on the number of unique pole figures used in the analysis and on the quality of the pole figure measurements Addi tional considerations for large grained materials or complex orientations are the statistical signifi cance of the grain sampling related to sample oscillation and the possibility of unobserved grains due to data collection conditions 5 10 M86 E01007 GADDS User Manual Texture 5 5 Other Texture Representat
216. on of the electron distribution in the sample A simple difference between the two is that WAXS has a diffraction 20 angle range of 0 5 to 180 while SAXS is in the range from 0 up to roughly 2 or 3 WAXS normally deals with long range periodicity in all three dimensions with the d spacing range from a fraction of 1 to 10 1 nm The crystal structures of most inorganic and organic materials fall into this cat egory The SAXS covers the size range between 10 and 1000 1 10 nm depend ing on the collimation system and not necessar ily with long range order within each particle The size shape and distribution of the particles are normally observed with SAXS With the HI STAR area detector the SAXS data can be collected at high speed Anisotropic fea tures from specimens such as polymers fibrous materials single crystals and bio mate rials can be analyzed and displayed in two dimension De smearing correction is not nec essary due to the collimated point X ray beam Since one exposure takes all the SAXS informa tion you can easily scan over the sample to map the structure information from the small angle diffraction M86 E01007 Small Angle X ray Scattering GADDS User Manual 9 1 1 General Equation and Parameters in SAXS SAXS pattern represents the scattering variation due to the point to point variations in electron density The variation can be expressed by the scattering amplitude of
217. ons usually have a maximum inten sity at the Bragg angle This means that several frames i e a rocking curve describe these reflections The rocking curve width is related to the distribution of the orientations of the molecu lar chains about the physical axis Note that in this discussion a rocking curve is not necessar ily an scan but may also be a or y scan depending on the orientation of the fiber This discussion applies to a single filament or a care fully prepared fiber bundle Preparation of a mul tiple fiber bundle should be done so that all of the fibers are oriented in the same direction and under the same tension Loose filaments are undesirable Keep in mind that the X ray beam is only 0 5 mm or less in diameter so every fiber contributes to the diffraction pattern Polymer orientation measurements are per formed in transmission Remember to use the beam stop The collimator size should be selected that is as near as possible to the diam eter of the sample This reduces parasitic air scatter The trade off here is that for single fila ments which are typically under 50 um in diame ter data collection times may be prohibitively long The compromise is to use a larger collima tor and subtract a background frame collected under the same conditions in the absence of the sample The length of time the background frame is collected can be less than that of the sample frame but long enough to ensure that statisti
218. or Position in the Laboratory System llsllellellelslses 1 11 1 4 Diffraction Data Measured by an Area Detector 0 00 ee 1 13 1 5 References so ELA ER CET e Ee eene det oae daraus v erbe E Ce EC Ere 1 15 2 System Configuration oscar rh hk eee 2 1 2 1 X ray Generator 5 2 vs eb Dri REXOV eem vd needed tede aad 2 3 2 1 1 Radiation Energy cocci es lee ule redu unde Pagi ee eid 2 3 2 1 2 X ray Spectrum and Characteristic Lines l lli iiie sees 2 3 2 1 3 Focal Spot and Takeoff Angle 1 2 0 2 0 cc cee 2 4 2 1 4 Focal Spot Brightness and Profile llle 2 5 2 1 5 Operation of the X ray Generator 0 2 0 ccc res 2 6 2 2 Klay Optics os o ees eg Meth oa Petedeeteher ws Bk eem bee onyx Sats deduci des open 2 8 2 2 1 Monochromator sius eter tee natin ee nee ate eg eee ba 2 9 2 2 2 Pinhole Collimator 0 2 0 0 000 cette ae 2 10 2 2 3 Sample to Detector Distance and Angular Resolution 00000e0 eae 2 13 2 2 4 Single and Cross Coupled G bel Mirrors liliis 2 22 M86 E01007 1 05 i Table of Contents GADDS User Manual 2 2 5 Monocapillary aio irra ue estore Xd CEPR en Oe wo Rr bU ae E A a 2 25 2 3 Goniometer and Stages 0 cnet eee 2 27 2 4 Sample Alignment and Monitor Systems 00 0c c eet 2 31 2 5 HI STAR Area Detector rdi e cette teens 2 34 2 6 Small Angle X ray Scattering SAXS Attachment 0 00 cece 2 36
219. or example 1 refers to the first parameter 2 refers to the sec ond parameter Up to ten parameters are allowed in a command the tenth being 0 Most parameter arguments are required Qualifiers Valued qualifiers and non valued qualifiers are collectively referred to as qualifiers Because they are identified by name quali fiers may occur in any order after the com mand name and may be intermixed with parameters Most qualifier arguments are not required You may abbreviate the quali fier s name but it must have enough char acters to be distinguished it from all other subcommands and qualifiers used for this verb Valued Qualifiers Valued qualifiers have the syntax lt name gt lt value gt where lt name gt repre sents the name of the qualifier and value is a text string S or numeric value lt N gt The value you specify for such a qualifier is related directly to the value you M86 E01007 Script Files GADDS User Manual specify for the corresponding input panel item in menu mode Non valued Qualifiers Non valued qualifiers have the syntax lt name gt and represents a corresponding menu mode input panel item which takes Y or N for yes or no as its value which includes all check box entries If the qualifier is present on the command line the effect is the same as if Y yes or checked was spec ified for the corresponding input panel item if absent the effect is an N n
220. or normal to a diffraction feature Record the length of the cursor D pixel from the statistics at the end of the screen Half the D pixel value gives the radius needed for the PERCENT_CRYSTAL FULL input screen The resulting frame from PERCENT_CRYSTAL FULL is an unwarped amorphous scattering frame Save the final frame under a new name To obtain the crystalline scattering frame use FILE LOAD with the original smoothed frame as the input file and the amorphous scattering frame as the background file using the argument SCALE 1 M86 E01007 Percent Crystallinity GADDS User Manual 8 2 2 Application Examples Depth Dependent Percent Crystallinity The GADDS system has high spatial resolution by virtue of its finely engineered point source and optics of fine magnification This magnifica tion enables sample properties to be character ized as a function of depth For example skin core effects in polymer sheets can be studied in transmission through thin sections The most convenient stage for such an operation is the XYZ stage though any stage can be used Figure 8 6 Depth dependent crystallinity measurements on polypropylene based material 200 um apart M86 E01007 GADDS User Manual Percent Crystallinity Percent Crystallinity of a Fiber Fibers are the most challenging samples for data collection and therefore determination of percent crystallinity Usually the fiber axis is close to t
221. osing the Detector Position 1 Ensure that the Detector Bias switch on the PDC is turned off N CAUTION To avoid damaging the detector always ensure that the Detector Bias switch is turned off before changing the sample to detector distance 2 Move the detector to the sample to detector distance you will use for your specific appli cation for optimum angular coverage and resolution per the following criteria e For the HI STAR area detector the angular coverage varies linearly from about 70 at 6 cm to 18 at 30 cm e Atthe same time the angular detector reso lution defined by tan angular detector res olution pixel dimension sample to detector distance changes from 1 02 in 2 theta for high resolution mode e n choosing the detector resolution and dis tance see also the tables in Section 2 To move the detector on the dovetail loosen the detector setscrews grasp and slide the detector at the dovetail mount for smoothest movement then tighten the set Screws M86 E01007 Basic System Operation GADDS User Manual AN CAUTION Avoid touching or scratching the detector window as it contains poisonous beryllium Position the detector precisely and with high reproducibility by putting a pin in the dove tail hole for the desired standard sample to detector distance Note the distance for later entry in the GADDS software Turn on the PDC and the detector high volt age In
222. ount mechanism allows the maximum 0 20 and o ranges for different configurations Two tracks are typically mounted on the D8 goniometer one for the X ray source and optics and one for the detector The T slot is available for mounting the sample alignment system or other attach ments A variety of sample stages are used in GADDS systems The sample stages are usually mounted on the inner 0 circle of the goniometer In 0 20 mode the sample rotation is defined as rotation so a sample stage directly mounted on the goniometer inner circle is also called w stage The most commonly used sample stages are fixed chi two position XYZ and 4 cradle Figure 2 10 M86 E01007 System Configuration GADDS User Manual d circle Eulerian Cradle c XYZ stage Figure 2 10 Four typical sample stages used in the GADDS system 29 M86 E01007 System Configuration GADDS User Manual Table 2 26 lists the specifications and typical Centric Motorized v X Y and Microdiffraction applications for these stages V Circle Z axes Phase ID Yoox Eulerian 11 lt g lt 98 Stress analysis Table 2 26 Specifications and Applications of Sample Cradle C8 lt v lt 101 Texture analysis Stages 0 c X Y mapping Stages Specification Application 40 mm X 40 mm High resolution 40 mm Y 40 mm diffraction Fixed Chi Motori
223. peak is observed at the Bragg angle 0 Figure 1 1 is an oversimplified model For real materials the diffraction patterns vary from the oretical delta functions with discrete relation ships between points to continuous distributions with spherical symmetry Figure 1 2 shows the diffraction from a single crystal and from a poly crystalline sample The diffracted beams from a single crystal point to discrete directions each corresponding to a family of diffraction planes The diffraction pattern from a polycrystalline powder sample forms a series of diffraction cones if a large number of crystals oriented ran domly in the space are covered by the incident X ray beam Each diffraction cone corresponds to the diffraction from the same family of crystal line planes in all of the participating grains The diffraction patterns from polycrystalline materi als will be considered later in the discussion of the theory and configuration of X ray diffraction using area detectors The theory also applies to any system with a two dimensional detector M86 E01007 GADDS User Manual Introduction and Overview Figure 1 2 The patterns of diffracted X rays a from a single crystal and b from a polycrystalline sample Polycrystalline materials consist of many crys talline domains numbering from two to more than a million in the incident beam In single phase polycrystalline materials all of these domains have the same crystal stru
224. ple with TITLE 2 Do not forget to add comments to explain arguments Print the script file Save script M86 E01007 10 17 Script Files GADDS User Manual The final script should look like PhaseID slm Qualitative Phase Identification Script File Version 1 0 Created by KLS 06Jan98 Last modified by no one This script will collect 4 frames at 20 45 70 95 deg integrate and merge results into a single range RAW file for input into EVA s search match routine Filename actually jobname part of filename Sample title often in double quotes Sample number often in double quotes Scan time may be time string HH MM SS S AP o9 oe oe A w Dp Step 1 define a new project GADDS 4 users only PROJECT NEW CNAME Corundum 0 TITLE Corundum Test Sample amp WORKDIR PROJECT FORMULA MORPH CCOL DENSITY amp DENSMETH CLEAR RESET Step 2 collect the frames and unwarp SCAN SINGLERUN 1 2THETA 20 0 OMEGA 5 0 PHI 0 0 CHI 54 74 AXIS 2 amp WIDTH 10 0 SCANTIME 4 TITLE 2 amp SAMPLE 3 NUMSAMPLE 0 NAME 1 RUN 0 FRAMENO 001 amp DISPLAY 16 REALTIME CLEAR MODE Scan SCAN SINGLERUN 1 2THETA 45 0 OMEGA 17 5 0 PHI 0 0 CHI 54 74 AXIS 2 amp WIDTH 10 0 SCANTIME 4 TITLE 2 amp SAMPLE 3 NUMSAMPLE 0 NAME 1 RUN 0 FRAMENO 002 amp DISPLAY 16 REALTIME CLEAR MODE Scan SCAN SINGLERUN 1 2THETA 70 0 OMEGA 30 0 PHI 0 0 CHI 54 74 AXIS 2 amp
225. polymorphism study in pharmaceutical chemistry and catalysis development in the oil industry a typical 20 measuring range is 2 60 It is necessary to run combinatorial XRD screen ing in transmission mode in order to avoid the defocusing effect A 2D diffraction system is designed for XRD screening in transmission mode for various applications including screen ing of material libraries for combinatorial chem istry As shown in Figure 2 25 the system is built on a vertical two circle goniometer An off set mounted XYZ translation stage yields space for an X ray source optics and X ray detector while it provides translations in X Y and Z direc tions for material library scanning and sample alignment A laser video sample alignment sys tem is mounted on the outer circle of the goni ometer so it can be driven away after alignment An optional motorized beam stop has two posi tions retracted position for loading unloading and aligning the sample and extended position during diffraction and scattering measurement In a transmission mode X ray diffraction mea surement the incident beam is typically perpen dicular to the sample so the irradiated area on the specimen is limited to a size comparable to the X ray beam size allowing the X ray beam concentrated to the intended measuring area In combinatorial screening applications sample cells are located close to each other Therefore transmission mode diffraction can also avoid
226. r the FTP in Fig ure 5 13 the reported w values representing the pole spread and texture strength are ogg 3 2 and oso 0 8 with 4 randomness The value t in Figure 5 14 represents the angle between the substrate normal and the normal to a given diffraction plane It is sometimes called the off cut or mismatch angle Its value is not important for the determination of a but is required to determine the relationship between the film and substrate orientations Because the FTP is essentially a slice of a com plete pole figure some of the information avail able in a complete set of pole figures is absent For example if the pole is not completely sym metric about the perfect fiber normal which can occur if the pole is tilted or spread in one direc tion the slice selected may misrepresent the true texture For this reason it is often useful to create FTPs from both one slice of about 10 and from a full 360 pole figure integration Oth erwise the more general ODF analysis is required M86 E01007 GADDS User Manual Texture 5 16 References 1 L E Alexander X Ray Diffraction Methods in Polymer Science Krieger Publishing Company Malabar Florida 1985 C F Blake On the Factors Affecting the Reflec tion Intensities by the Several Methods of X Ray Analysis of Crystal Systems Rev Mod Phys 5 3 169 202 1933 H J Bunge Texture Analysis in Materials Sci ence Butterwo
227. r to make the GADDS geometry definition consistent with other Bruker XRD systems the v angle will be used in the later version of GADDS system The next rotation above o and y is rotation The sample translation coordi nates XYZ are so defined that when o xg gt 0 X is in the opposite direction of the incident X ray beam X X Y is in the opposite direc tion of Y Y Y and Z overlaps with Z Z In GADDS it is very common to set the y 90 w 0 for a reflection mode diffraction as is M86 E01007 GADDS User Manual Introduction and Overview shown in Figure 1 7 b In this case the relation ship becomes X X Y Z and Z Y when o wy 0 The 6 rotation axis is always the same as the Z axis at any sample orientation In an aligned diffraction system all three rota tion axes and the primary X ray beam cross at the origin of X Yi Zi coordinates This cross point is also known as goniometer center or instrument center The X Y plane is normally the sample surface and Z is the sample surface nor mal In a preferred embodiment XYZ transla tions are above all the rotations so that the translations will not move any rotation axis away from the goniometer center Instead the XYZ translations bring a different part of the sample into the goniometer center Due to this nature if a sample is moved for the distances of x and y away from the origin in the X Y plane the new spot on the sample
228. ray scattering from a crystalline material produces well defined spots or rings which integrate to sharp higher inten sity peaks Percent crystallinity as obtained by X ray measurements is defined as the ratio of intensity from the crystalline peaks to the sum of the crystalline and amorphous intensities percent crystallinity lcrystalline lcrystaltine lamorphous The measured total intensity may have signifi cant contributions other than crystalline and amorphous scattering from the sample Air scat ter specimen holder scatter e g capillary glass scatter and Compton or incoherent scatter must be taken into account M86 E01007 GADDS User Manual Percent Crystallinity Figure 8 2 A Nylon frame with air scatter B air scatter frame C Nylon frame with air scatter subtracted You can correct air scatter occurring after the specimen and specimen holder scatter by mea suring blank frames under identical conditions as the sample with the exception of the mea surement time You subtract these frames from the data frames using FILE LOAD with the SCALE n qualifier which scales the back ground frame to the time of the data frame Note that the beam stop must not be repositioned between the measurement of the blank and data frames for measurements in transmission mode The beam stop will also cause considerable scattering if it is not properly aligned to block the primary beam A pair
229. re typically saddled in the center with the maximum near the edge The intensity at the center can be as low as 50 of the maxi mum The focal spot profile for RAG is normally more evenly distributed like a flat topped Gaus sian distribution The focal profile from a fine focus or long fine focus sealed tube can satisfy most GADDS applications The micro focus sealed tube and RAG may be necessary for some applications 2 1 5 Operation of the X ray Generator Correct and careful operation of an X ray gener ator is critical for satisfactory performance and useful lifetime All X ray tubes have a maximum power rating which defines the highest power input to the tube A cathode current vs anode voltage chart or table is normally supplied for a sealed tube The tube s filament current is also provided by the tube vendors D8 DISCOVER with GADDS uses the K760 or K780 X ray Gen erator C79249 A3054 A3 A4 The following information is for the K760 The K780 is only controlled by the software Detailed information for installation and opera tion is available in the vendor s Operating Instructions C79000 B3476 C182 06 Refer to the manufacturer s manuals if your system has a rotating anode generator RAG Generally you should adapt the following precautions when operating an X ray generator 1 Before starting the generator 1 1 Make sure the cooling water supply is available and running properly temper ature pressure f
230. rial Differentiating this equation the opti mal thickness of the sheet to obtain the maxi mum transmitted intensity is found to equal the inverse of the material s linear absorption coeffi cient You should align the polymer sheet similar to that of a fiber except that you should set a machine direction along the axis Once the sheet is in place so that the sheet normal is along the microscope axis update 0 with COLLECT GONIOMETER FIXED AXES If the sheet is supported make sure the X ray beam does not hit the frame during rotation If hit an intensity of zero will be merged with a positive intensity collected at another orientation M86 E01007 GADDS User Manual Percent Crystallinity Reflection Data Collection Reflection mode data collection for percent crys tallinity measurements is performed in a similar manner as transmission work except that only 45 of the diffraction sphere is available This low percentage is not a problem for powdered samples because the sample is rotated and o is scanned over 2 during data collection The low percentage does become a problem for plate and needle samples however For these samples prepare or mount the sample such that the unique axis or plate normal is not along a rotation direction This holds true for other sam ples with preferred orientation as well A check to see if most or all of the preferred ori entation was eliminated is to overlay a PDF card with
231. rom the peak maximum and set the scan width to the reflection breadth If multiple frames are necessary to collect data out to 68 20 with Cu radiation take great care when integrat ing x in overlapping 20 regions Try to obtain all of the meridional and equatorial reflec tions in one frame at low angles Usually the meridional reflections on most fibers become very weak above 30 20 In merging the integrations from the frames for profile analysis with DIFFRACP SProfile use the following scheme 1 Subtract a background scattering frame from each frame using FILE LOAD with the SCALE n qualifier which scales the back ground frame to the time of the data frame If the sample is broader than the beam use an attenuation factor GADDS obtains the scale factor from the absorption formula lylo e where u is the linear absorption coefficient of the material and tis its average thick ness For C H compounds the absorption is usually less than 3 Therefore if the M86 E01007 Percent Crystallinity GADDS User Manual background frame and the data frame were collected for the same time the scale factor would be 0 97 instead of 1 00 2 Integrate each frame setting y to a unique part of reciprocal space usually a quadrant 3 If two or more frames are required in y to obtain all the scattering check the y limits so the regions integrated over do not over lap 4 Use the MERGE utility with the S
232. rt GADDS online version for your partic ular stage Collect gt Goniometer gt Manual command Using the manual control box drive omega phi and or chi until the microscope is view ing down the sample s surface plane Using the goniometer head tool adjust X Y and or Z until the surface plane is center along the crosshairs cursor If possible drive 180 in omega and look down the other direction Exit manual command by pressing ESC on the frame buffer s keyboard M86 E01007 Basic System Operation GADDS User Manual 3 6 3 Collision Limits for Your Sample A GADDS system has many moving compo nents such as the detector X ray source optics and sample stages Caution must be taken to prevent collision between moving or stationary components and samples A collision may cause component damage sample dam age or misalignment In order to prevent colli sions between components and samples GADDS systems have many hardware limit switches and software controlled limits depend ing on the configuration Due to the complexity of a GADDS system and variety of sample size and shape those limit switches and software limits can protect the system only if used with caution Some good practices for operating a GADDS system are the following e Be aware of the locations and set limits of all the hardware limit switches Consult Bruker Service if you need this information e If itis necessary to relocate the
233. rt of a grid with equal spacing between targets M86 E01007 Mapping GADDS User Manual 12 1 Procedure Demo Data The GADDS software either offline or online versions must have loaded the project in which the data frames are located Project gt Load Once you have the project loaded go to Analyze gt Mapping Options for Analyze Mapping 7 X r Frames to process First frame MAP 0 001 gfrm El To frame number 001 To run number G Last frame MAP_0G_001 gfrm Processing parameters Map Parameter Ti SLAM Figure 12 1 Analyze gt Mapping Using the input information from above you will see a demonstration of how the mapping soft ware works Once started the GADDSmap soft ware automatically starts importing in computer generated data into a multiple spot array What you will see from the GADDSmap software is shown in Figure 12 2 12 2 M86 E01007 GADDS User Manual Mapping GE GADDSmap C frames 2003 Mar unknown0 MAP gmap File Edit view Window Help 1 d 1 mm Title Demo Test User GADDS user Site Bruker AXS Inc Zoom out the active document reduce Figure 12 2 GADDSmap Units Unknown M86 E01007 12 3 Mapping GADDS User Manual 12 2 Procedure Real Data In the evaluation of actual data however you will have to change the input parameters to fit the specific functionality that you are looking for In th
234. rths Boston 1982 H J Bunge ed Experimental Techniques of Texture Analysis DCM Informationsgesellschaft Germany 1986 B D Cullity Elements of X ray Diffraction Addi son Wesley New York 1978 C R Desper and R S Stein Measurement of Pole Figures and Orientation Functions for Poly ethylene Films Prepared by Unidirectional and Oriented Crystallization J Appl Phys 37 11 3990 4002 1966 International Tables for X ray Crystallography Vol II Kynoch Press Birmingham 1967 D B Knorr H Weiland and J A Szpunar Applying Texture Analysis to Materials Engi neering Problems J Materials 46 9 32 36 1994 D B Knorr and J A Szpunar Applications of Texture in Thin Films J Materials 46 9 42 47 1994 10 11 12 13 14 M Lorenz and K C Holmes Computer Pro cessing and Analysis of X ray Fibre Diffraction Data J Appl Cryst 26 82 91 1993 D E Sands Vectors and Tensors in Crystallog raphy Addison Wesley New York 1982 J L White and J E Spruiell Specification of Biaxial Orientation in Amorphous and Crystalline Polymers Polym Eng Sci 21 13 859 868 1981 Z W Wilchinsky Recent Developments in the Measurement of Orientation in Polymers by X ray Diffraction Adv X ray Anal 6 231 241 1962 H J Bunge Cesling Advances and Applications of Quantitative Texture Analysis Clausthal 1989 M86
235. s St Martin s Press New York 1970 S N Sulyanov A N Popov and D M Kheiker Using a Two Dimensional Detector for X ray Powder Diffractometry J Appl Cryst 27 pp 934 942 1994 Hans J Bunge and Helmut Klein Determination of Quantitative High Resolution Pole Figures with the Area Detector Z Metallkd 87 6 pp 465 475 1996 10 11 12 13 14 Kingsley L Smith and Richard B Ortega Use of a Two Dimensional Position Sensitive Detector for Collecting Pole Figures Advances in X ray Analysis Vol 36 pp 641 647 Plenum New York 1993 Bob B He and Kingsley L Smith Strain and Stress Measurement with Two Dimensional Detector Advances in X ray Analysis Vol 41 Proceedings of the 46th Annual Denver X ray Conference Steamboat Springs Colorado USA 1997 Bob B He and Kingsley L Smith Fundamental Equation of Strain and Stress Measurement Using 2D Detectors Proceedings of 1998 SEM Spring Conference on Experimental and Applied Mechanics Houston Texas USA 1998 Bob B He Uwe Preckwinkel and Kingsley L Smith Advantages of Using 2D Detectors for Residual Stress Measurements Advances in X ray Analysis Vol 42 Proceedings of the 47th Annual Denver X ray Conference Colorado Springs Colorado USA 1998 Roger D Durst et al The Use of CCD Detectors for X ray Diffraction invited paper to 1998 Den ver X ray Conference M86 E01007 Introduction and Overview GADDS User Ma
236. s You should select a set of parameters and settings for a particular material and use the same parameter and settings for all the same materials It is deceptive to compare stress val ues calculated with different parameters or set tings M86 E01007 Residual Stress GADDS User Manual 4 Click the mouse on the frame to process the data Calculated stress is reported as shown in Figure 6 18 Biaxial Stress Tensor from Area Detector data Figure 6 18 Stress result menu showing normal stress In the above example all the seven frames were collected with scan only 0 y 0 g 90 and w 57 72 87 102 117 132 and 147 respectively For stress tensor mea surement the data frames should be collected with two or more scanning angles For example for a set of seven frames collected at Frame 1 2 3 4 5 6 7 w 57x 72x 87x 102x 117x 132x 147x f Ox 45x 90x Ox 45x 90x Ox M86 E01007 GADDS User Manual Residual Stress Following the same steps the stress result is given as shown in Figure 6 19 Biaxial Stress Tensor from Area Detector data Figure 6 19 Stress result menu showing biaxial stress tensor The quality of the stress measurement can be evaluated by viewing the peak fitting data points peak 20 values and a diffraction ring calcu lated from the stress result Follow these steps 1 Afterthe stress
237. s com puted under the same conditions with a polynomial background The linear back ground should provide an upper limit to the crystallinity value The extent in y is arbi trarily chosen To be confident in your results repeat the measurements on the same system and obtain identical values of all angles as these are necessary External Method PERCENT CRYSTAL EXTERNAL The external method is used for oriented poly mers 1 To determine the boundaries of the amor phous region integrate this area using PEAKS or DIFFRACP 5Profile an optional package If you use PEAKS do not use the default peak function which is too sharp Instead model the peak with PEAKS SIMU LATE with an appropriate FWHM The final fitting will show the extent 20 limits of the amorphous region The amorphous region rather than the region containing both crystalline and amorphous scatter will give the best information on the extent of the amorphous scatter Enter these values for the lower and upper limits on the amorphous external function The same 20 limits can also be used for the crystalline region Examine the crystalline region with a 20 integration to determine the boundary in x to set for the crystalline scattering Note that the crystalline region must also contain amorphous scatter However this region must not overlap with the previously selected amorphous region The amor phous y range does not have to match th
238. s eee eee 6 34 6 5 Bieferences e skeen bd ecards ere ud Rar 6 36 T GEIyStal SITO iuis Qu a RR ERR gor Fa AR ROCA ARR eae EUR RA ee RU 7 1 7 1 Line Broadening Principles for Crystallite Size liliis 7 1 7 2 Instrumental Broadening 000 aa E nh 7 2 7 3 Microstrain Broadening i seso Tot pasip cc eee mes 7 6 7 4 Data Collection for the Warren Averbach and Scherrer Methods 2 0005 7 7 7 5 References Tet pesas bie poet Pade a bet ie ad toe A fee ho i vRprhrbass 7 8 8 Percent Crystallinity ead ux x ance 2 awed eee ee news owe Rc Ed 8 1 8 1 Principle of Percent Crystallinity 0 0 0 2 tees 8 1 8 2 Data Evaluation for Two Dimensional Data 0 0000 eee 8 4 8 2 1 Methods Supporting Percent Crystallinity liens 8 4 8 2 2 Application Examples lsseeeeeeeee RI en 8 10 8 3 Heferences o erp Uude nere E Re cq eere popuh bee aedi ee 8 16 9 Small Angle X ray Scattering 0000 e eee 9 1 9 1 Principle of Small Angle Scattering 0 0 0 cette 9 1 9 1 1 General Equation and Parameters in SAXS 0 0 00 ccc cee eee 9 2 9 1 2 X ray Beam Collimation 0 0 0 sse rh 9 3 9 2 Data Collection and Analysis 00 ccc tetas 9 5 9 2 1 SAXS Attachments Installation 0 0 0 c eee 9 5 9 2 2 SAXS System Adjustment and Calibration 0 00 00 ccc eee 9 7 9 2 9 Data Collections 0 evn ocean tnd tees Oe dre he ERE EUR wee pes ae VN 9 11 9 3 14 Applic
239. s scripts 96WellsSub inc R wend Targets E01 to E12 let R E01 while SR lt E12 do gadds scripts 96WellsSub inc R wend Targets F01 to F12 let R F01 while SR lt F12 do gadds scripts 96WellsSub inc R wend oe mn oo mn oo mn oo mn oo mn oo W oo el oo W oo W oo pel oo W Targets G01 to G12 let while Targets H01 to H12 SR H01 SR lt H12 do gadds scripts 96WellsSub 1 R inc R wend File 96wellssub slm let R G01 while SR lt G12 do gadds scripts 96WellsSub 1 R inc R wend Nested script file used by 96wells slm 1 jobname 2 run A01 A02 B01 etc If frame doesn t exist processing this frame don error then stop load and in we exit tegrate 1st frame display new 1 2 001 gfrm INTEGRAT 58 800 NORMAL 5 STEPSIZI TE WRITE TITLE amp INTEGRAT FILENAME BASENAME amp FORMAT DIFFRACplus SCALE 1 0 load and in DISPLAY NEXT INTEGRAT 71 300 NO INTEGRAT TE CHI 26 000 54 400 RMAL 5 STEPSIZE 0 050 TE WRITE STITLE amp BH UE CHI 10 600 31 500 122 600 amp 0 050 tegrate 2nd frame 109 200 amp M86 E01007 11 3 Automation GADDS User Manual FILENAME SBASENAME amp FORMAT DIFFRACplus SCALE 1 0 APPEND Now merge the two ranges into a single range system c saxi ga
240. sed on the user selected parameters M86 E01007 System Configuration GADDS User Manual 2 8 1 Reflection Mode Screening 04 track A 2D detector is mounted on a dovetail track the 05 track The XYZ stage is located with X Y in the horizontal surface and Z vertical A laser video system is used to align and moni tor the sample An XRD combinatorial screening system mainly for reflection mode screening is shown in Figure 2 21 drawing and Figure 2 22 photo All components are mounted on a vertical 0 0 goniometer The X ray tube and optics are mounted on a dovetail track referred to as the Laser video microscope Graphite monochromator Xray source Collimator XYZ stage Figure 2 21 Drawing of an XRD combinatorial screening system including a 2D detector X ray generator X ray optics monochromator and collimator theta theta goniometer XYZ sample stage and a laser video sample alignment and monitoring system 2 46 M86 E01007 GADDS User Manual System Configuration Figure 2 22 Photo of an XRD combinatorial screening system including a 2D detector X ray generator X ray optics monochromator and collimator theta theta goniometer XYZ sample stage and a laser video sample alignment and monitoring system The X ray beam is monochromatized with either a graphite monochromator or a multi layer mir ror The X ray beam can be collimated to vari ous sizes by using a pinho
241. speed and high accu racy It is very suitable for samples with large crystals and textures Simultaneous measure ment of stress and texture is also possible since 2D data consists of both stress and texture information Percent crystallinity can be measured faster and more accurately with the data analysis over the 2D frames especially for samples with anisotro pic distribution of crystalline orientation The amorphous region can be defined externally within a user defined region or the amorphous region can be defined with the crystalline region included when the crystalline region and the amorphous region overlap GADDS can also calculate and display the Compton scattering so the Compton effect can be excluded from the amorphous result The rolling ball algorithm calculates the percent crystallinity by extracting an amorphous background frame Small angle X ray scattering SAXS data can be collected at high speed Anisotropic features from specimens such as polymers fibrous materials single crystals and bio materials can be analyzed and displayed in two dimensions De smearing correction is not necessary due to the collimated point X ray beam Since one exposure takes all the SAXS information it is easy to scan over the sample to map the struc ture information from the small angle diffraction Microdiffraction data is collected with speed and accuracy X ray diffraction from small sample amount or small sample area h
242. stance and automatically computing and installing a spatial correction for data subsequently col lected at the same distance Spot Focus The projection of the focal spot along the focal spot length with a takeoff angle is spot focus also called square focus or point focus The spot focus is commonly used with a 2D detector Synchrotron Radiation Radiation emitted by very high energy elec trons such as those in an electron storage ring when their path is bent by a magnetic field The radiation is characterized by a continuous spectral distribution a very high intensity a pulsed time structure and a high degree of polarization Takeoff Angle The angle between the anode and the exit X ray beam in a sealed X ray tube or RAG Target X ray The electrode in an X ray generator which emits X rays when bombarded by fast elec trons Also called anode Transmission mode The diffraction condition that occurs when the incident beam strikes the sample in one surface and the diffracted beam exits from the opposite surface The transmission mode diffraction commonly applies to thin plate samples White Radiation Any radiation such as sunlight with a con tinuum of wavelengths The term used here denotes the X ray radiation with such a con tinuum of wavelengths It is also called Bremsstrahlung X rays Electromagnetic radiation of wavelength 0 1 100A produced by bombarding a target generally a metal such as
243. t specify parameters where one is required Unspecified parameters are replaced by blanks which typically will cre ate problems executing the script file You must enclose inside double quotes any parameter that contains slashes or embed ded spaces You cannot use double quotes on any parameter that is used to represent part of an entire argument If your script file command is TITLEz 961 962 And you invoke the script command MyScript This is my sample XYZ The program will stop on the illegal com mand TITLE This is my sample XYZ The second double quote is in an invalid position Example Say you wish to identify the phases of numerous samples Rather than create a separate script file for each sample you can modify the script you created in previous section which identifies the phases of the specific corundum sample to use replaceable parameters as follows 1 Create and test the script without replace able parameters You have already done this in section 10 3 2 Determine which parameters should be replaceable Any parameter that is unique to the sample must be replaceable For this script use 1 for filenames 2 for the sample title 3 for sample name 4 for the scan time 3 Using NotePad edit the script file to use the replaceable parameters you have chosen For example in line 13 you would replace SCANTIME 1 00 00 with SCANTIME 4 and TITLE Corundum Test Sam
244. ta frame magnified by 4x The chi integrated profile in the chi range of 75 105 and two theta range of 0 3 2 shows the third sixth and ninth order peaks of SAXS pattern from the rat tail tendon sample M86 E01007 GADDS User Manual Small Angle X ray Scattering Figure 9 8 Conic cursor shows the maximum resolution by the beam stop edge at chi 90 is 248 A M86 E01007 9 13 Small Angle X ray Scattering GADDS User Manual chi integrati on box I n t e n E i t y 9 Qq 1 nm gt 2 theta in degrees Figure 9 9 The chi integrated profile in the chi range of 75 to 105 and two theta range of 0 3 to 2 shows the third sixth and ninth order peaks of SAXS pattern from the rat tail tendon sample M86 E01007 GADDS User Manual Small Angle X ray Scattering 9 3 Applications Examples Types of information obtainable from small angle X ray scattering include Lamellar repeat distance the distance from the center of one bi layer to the center of its neighbor which includes the thickness of associated water layers Radius of gyration the first moment of the scattering center distribution function Large scale structure 25 5 000 A with pinhole optics and long range order dis tances between similar structures For example the pattern in Figure 9 10 can yield the arrangement of a column structure its diameter and the distances between col umns
245. tal 5 0 amp theta2 5 0 axis 2 width 10 amp scantime T title 3 sample 4 amp numsample 5 name 4 run R amp frameno 001 display 15 realtime amp clear mode scan oscillate XY amp amplitude 1 Collect 2nd frame 2T 20 OM 5 to 5 scan singlerun 1 thetal 5 0 amp theta2 15 axis 2 width 10 amp scantime T title 3 sample 4 amp numsample 5 name 4 run R amp frameno 002 display 15 realtime amp clear mode scan oscillate XY amp amplitude 1 Collect 3rd frame 2T 40 OM 5 to 5 scan singlerun 1 thetal 5 0 amp theta2 35 axis 2 width 10 amp scantime T title 3 sample 4 amp numsample 5 name 4 run R amp frameno 003 display 15 realtime amp clear mode scan oscillate XY amp M86 E01007 11 5 Automation GADDS User Manual amplitude 1 ENDIF To next target in EditTargets list inc N wend The frame processing is extracted into a sepa rate script file Example 11 3 Frame processing File 96WellsProcess slm Process frames in a 96 well library Assumes Frames collected using 96WellsCollect sim Assumes Used run numbers A01 to H12 1 jobname base of filename Integrate all frames on error then continue Targets A01 to A12 let R A01 while SR lt A12 do gaddsSscripts 96WellsSub 1 R inc SR wend etc as in Phase 1 Primitive Automation example 11 3 Sample Handling
246. tectors There are many advantages of using 2D detec tors for residual stress measurement no matter if the conventional sin y theory or the new 2D theory is used The experiments have shown that advantages to using 2D detectors for stress measurement include but are not limited to high sensitivity high measurement speed high accuracy and virtual oscillation for large crys tals and textured samples In the case of materials with large grain size or microdiffraction with a small X ray beam size the diffraction profiles are distorted due to poor counting statistics To solve this problem with conventional detectors some kind of sample oscillations either translation oscillations or angular oscillations are used to bring more crystallites into diffraction condition In another words the purpose of oscillations is to bring more crystallites in the condition such that the normal of the diffracting crystal plane coincides with the instrument diffraction vector For 2D detectors when the y integration is used to gen erate the diffraction profile we actually integrate the data collected in a range of various diffrac tion vectors The angle between two extreme diffraction vectors is equivalent to the oscillation angle in a so called w oscillation Therefore we may call this effect virtual oscillation Figure 6 5 shows the relation between the y integration range Ay and the virtual oscillation angle Ay The 20 value of the
247. terials For more general crystal classes use the orientation matrix approach using PEAKS REFL ARRAY pro vided the films are near single crystal Figure 5 10 111 pole figure of an epitaxial thin film of SiGe deposited on a single crystal Si substrate The larger darker spots are from the substrate reflections CURSOR PIXEL gives the intensity at the inter section of the crosshairs and the values of a and p By definition o 0 at the outer edge and a 90 at the center of the pole figure Con versely y 0 at the center and y 90 at the outer edge of the pole figure CURSOR BOX CURSOR CONIC and CUR SOR VECTOR are not particularly useful for pole figure evaluation M86 E01007 GADDS User Manual Texture 5 13 Preparation for ODF Analysis with popLA and ODF AT Preferred Orientation Package Los Alamos popLA performs an ODF using vector meth ods The orientation space is divided up into a number of cells within which the ODF is assigned a constant value A simple initial value of each cell is determined from the experimental data The resultant pole figures from such an ODF are compared with the observed pole fig ures and adjustments are made to improve the match This process is repeated until no further improvement is observed Vector methods are best suited to ODF s which contain a few sharp features The second line of the popLA file contains an RM parameter which is the maximum pole
248. the hkl values of the measured reflections a crystallite size distribu tion and a microstrain distribution are obtained which yield an average crystallite size and root mean squared microstrain The Single Line method is based on the Warren Averbach method with additional assumptions i e crystal lite size broadening has a Cauchy profile while microstrain broadening has a Gaussian profile It can be used when only one diffraction peak is available for analysis provided that both crystal lite size and microstrain effects are present in the sample of interest The Single Line method also provides a crystallite size distribution but one of the assumptions is that the microstrain is constant DIFFRACP S Profile an optional package cal culates crystallite size using an implementation of the Scherrer equation DIFFRAC S Crysize an optional package implements the Warren Averbach and Single Line methods Refer to the software manuals and online help files of those packages for details Since the derivations and assumptions behind the Scherrer method and the Warren Averbach method differ see Klug and Alexander 1974 for details the average crystallite size values obtained from each method will not necessarily be comparable For many applications precision reproducibility is more important than absolute accuracy These methods and variations thereof are frequently used for quality control comparisons M86 E01007 GA
249. the HI STAR area detector The parallax effects disappear for long sample distances We recommend performing these steps every six to eight weeks and whenever you change the sample to detector distance For high reso lution applications you might have to perform them more often You should verify that the cor rect flood field and spatial corrections are loaded If not loaded see your Administrator and refer to the GADDS Administrator Manual NOTE If you perform this procedure at one dis tance then another and then return to a previ ous distance you can avoid performing this procedure again and instead automatically load the correction files and settings for that previous distance using the command Process gt Flood gt Load and Process gt Spatial gt Load Perform the corrections as follows 1 Mount the glassy iron foil for Cu radiation or the Fes source for other radiation on the sample stage and ensure that the sam ple and detector surface are parallel For exact alignment see Sample Positioning A Protective cap cover source when not in use Io detector Setscrew 55 Fe source must secures pin face detector Setscrew secures shaft Goniometer head Figure 3 2 Fe5 source mounting detail 2 Setthe detector bias switch for the radiation you will use as follows When using Cu radiation as the standard radiation set the bias switch at the PDC to Auto and use the com
250. the incident angle 04 diffract ing angle 05 and the gap 6 is S d5 cotd cotd for a given cell size or distance between the center of adjacent cells The required knife edge gap is given as EM Bo a cot0 cot0 If a range of 04 and 05 angles are used for the data collection use the lowest possible angles for this calculation Retract 2 knife edge Move XYZ stage to locate the next cell Align the cell to instrument center i Stop if Drive Z last cell down Collect diffraction data l Extend knife edge M86 E01007 GADDS User Manual System Configuration 2 8 5 Diffraction Mapping and Results Display The multiwire area detector can capture a large area of diffraction data containing information for various applications such as Phase ID qual itative or quantitative Percent Crystallinity Par ticle Size and Shape Texture and Stress Figure 2 30 shows two examples of the diffrac tion frame and integrated diffraction profile each from a single library point Almost all of the parameters measured by X ray diffraction can be used for the screening of material libraries The data collection grid including XYZ coordi nates of all the cells is determined by GADDS software based on the coordinates of the two cells at extreme positions lower left and upper right and step size between cells The data c
251. the intensities corrected for variable slits These patterns are from randomly oriented specimens If the measured intensities show the same trend then the data can be used for per cent crystallinity determination M86 E01007 Percent Crystallinity GADDS User Manual 8 3 References 1 L E Alexander X Ray Diffraction Methods in Polymer Science Krieger Publishing Company Malabar Florida 1985 International Tables for X ray Crystallography Vol III Kynoch Press Birmingham 1968 N S Murthy and H Minor General procedure for evaluating amorphous scattering and crystal linity from X ray diffraction scans of semicrystal line polymers Polymer 31 996 1002 1990 N S Murthy H Minor M K Akkapeddi and B Van Buskirk Characterization of Polymer Blends and Alloys by Constrained Profile Analy sis of X Ray Diffraction Scans J Appl Polym Sci 41 2265 2272 1990 K B Schwartz J Cheng V N Reddy M Fone and H P Fisher Crystallinity and Unit Cell Vari ations in Linear High Density Polyethylene Adv in X Ray Anal 38 495 502 1995 M86 E01007 GADDS User Manual Small Angle X ray Scattering 9 Small Angle X ray Scattering 9 1 Principle of Small Angle Scattering The physical principle of small angle X ray scat tering SAXS is the same as for wide angle X ray scattering WAXS Both techniques observe the coherent scattering from a sample as a functi
252. the replaceable parameter CorundO The second script UpdateFrames calls the third script Update Header with the replaceable parameter Corund0 000 The third script UpdateHeaders executes the commands LOAD Corund0 000 USER CONFIG SAVE Corund0 000 Once the third script UpdateHeaders termi nates flow returns to the next line of the second script which calls the third script with the replaceable parameter Corund0 001 Flow con tinues stepping through the entire frame series of files Corund0 000 to Corund0 071 Now the second script UpdateFrames terminates and flow returns to the next line of the first script which calls the second script with the replace able parameter Corund1 And so on 10 24 M86 E01007 GADDS User Manual Script Files 10 7 Flow Control Inside Script Files GADDS executes script commands sequen tially from first to last You can modify this sequence by using blocks of executable com mands and by transferring control to other com mands Requires release 4 0 14 Note Program variables such as 1 F etc are not translated inside any flow control statement LET A string value Define the value for a string variable A blank value is valid Any value that contains slashes or embedded spaces must be enclosed within double quotations When nesting script files the variable value is inherited from the parent script for program New variable values are not propag
253. tic properties and with other effects such as catalytic activity 7 1 Line Broadening Principles for Crystallite Size The traditional measure of crystallite size is based on the Scherrer equation CX Bcos0 where 1 is the X ray wavelength A B is the full width at half maximum FWHM of the peak radians corrected for instrumental broadening 0 is Bragg angle C is a factor typically from 0 9 to 1 0 depending on crystallite shape see Klug and Alexander 1974 and tis the crystallite size A The FWHM values are those of unre solved Ka peaks not those of resolved Ka peaks This equation shows an inverse relation ship between crystallite size and peak profile width the wider the peak the smaller the crys tallites M86 E01007 Crystal Size GADDS User Manual Not all peak broadening is due to crystallite size however Both instrumental broadening and microstrain can contribute to peak broadening and influence peak profile shape 7 2 Instrumental Broadening Determination of all peak broadening due to instrumental parameters e g collimator size detector resolution beam divergence is critical Only peak broadening due to crystallite size should be considered in the crystallite size cal culation To correct for instrument broadening a standard such as NIST SRM 660 LaBg lantha num hexaboride should be measured With this standard all broadening is due to instrumental parameters which includ
254. time long enough to ensure that statisti cally reliable corrections can be made Subtract this frame from the original frame using FILE LOAD with the SCALE n qualifier which scales the background frame to the time of the data frame If you observe significant absorption in the polymer sam ple scale the background frame so that the parasitic scattering around the beam stop is reduced to near zero For 0 3 mm or larger collimators use the 6 beam stop Other wise use the 4 beam stop M86 E01007 GADDS User Manual Percent Crystallinity the 4 cradle this restriction is removed by placing x 0 8 Use COLLECT GONIOMETER FIXED AXES to set y 0 If the fiber is instead mounted at 54 74 do not update the y value If you must collect angles gt 30 on the meridian physically remount the sample so Figure 8 7 Wire fiber holder attached to an SEM specimen that the fiber axis is horizontal For those mount The dashed line is a fiber measurements update x to 90 5 Tie a fiber no longer than 2 cm on a wire frame such as a paper clip fashioned as shown in Figure 8 7 The distance from the fiber to the back portion of the frame should be no longer than 1 5 cm 6 Affix the fiber frame with wax or clay to an aluminum SEM specimen holder available from electron microscopy supply houses Then mount the holder in the goniometer head The goniometer head used for mount ing fibers should be of the eucentric
255. ting FA M P P di TD lo WER M Transmission Transmission fiber PD 1 sheet PD 1 Figure 5 6 Relationship between the significant directions in texture specimens and their associated pole figure In Figure 5 6 the upper diagrams represent the physical sample while the lower represent the corresponding pole figures FA is the fiber axis MD is the machine direction This is usually a processing direction e g drawing or rolling direction TD is the transverse direction N is the normal direction MD TD and N are orthog onal The MD in the pole figure is determined by o Position the sample MD at for the result ing pole figure to have its MD pointing conven tionally vertical N pe TD M TD Reflection PD 3 M86 E01007 GADDS User Manual Texture Once a suitable set of data collection parame ters is determined with POLE_FIGURE SCHEME change the output filename from null to scan to update the scan lines in the MULTIRUN list The data collection parameters may be edited with COLLECT SCAN EDITRUNS e g reduce the default data collec tion time from 120 sec 5 7 Using POLE FIGURE PROCESS Once the pole figure frames are collected the following two processing steps are used to cre ate a pole figure 1 Apply Lorentz and polarization corrections if desired using the appropriate CORREC TION command The Lorentz correction depends on the diffraction geometry an
256. ting the X Y position of each X ray photon Data from the PDC transfers to the frame buffer computer over a 32 bit wide parallel data link allowing the frame to be dis played in real time as a 512x512 or a 1024x1024 pixel frame with 32 bit data for each pixel or to be stored in 8 16 or 32 bit frames Because the detector is sealed the xenon tube remains stable for years and adjustments to its circuitry are not usually necessary Adjustment of the detector bias is however required for use M86 E01007 System Configuration GADDS User Manual with different X ray sources Two preset bias settings are available normally one for the given X ray source and one for the calibration source Two settings can be selected automatically or manually 2 6 Small Angle X ray Scattering SAXS Attachment The small angle X ray scattering SAXS attach ment is designed for GADDS users to perform small angle X ray scattering measurements Figure 2 15 The beam stop assembly shown is mounted directly to the face of the HI STAR detector You align the beam stop using a pair of micrometers The helium beam path can be adjusted over a range of sample to detector dis tances The vacuum beam path designed for a long sample to detector distance of 60 cm is also available to achieve higher resolution micrometer k beamstop i Figure 2 15 Helium beam path for small angle X ray scattering measurement
257. tio v and anisotropic factor Agx Among these parameters the most important parameters are Young s modulus E and Poisson s ratio v In principle stress and strain values can be determined from any mea sured diffraction rings in either transmission mode or reflection mode using the 2D method with given E and v In order to have a higher angular resolution and enough sample rotation range diffraction rings with 20g in the range of 110 to 160 are preferred Table 6 2 lists the parameters for most commonly used materials These parameters are supplied only for your convenience Since the parameters especially E and v are different with different material con ditions different experimental methods or even different theoretical assumptions you are encouraged to determine the parameters based on your experience and sources M86 E01007 GADDS User Manual Residual Stress Table 6 2 The parameters of commonly used materials for stress measurement Materials a c du HKL Target 209 E n Arx Parameter A A degree MPa Ferritic and martensitic 2 866 1 170 211 Cr 156 0 210000 0 280 1 49 stest bec 1013 220 Co 124 1 Austenitic Steel fcc 3 571 1 268 220 Cr 130 2 180000 0 3 1 72 1 031 222 Co 120 5 0 798 420 Cu 149 8 Aluminum fcc 4 049 1 224 311 Cr 139 5 70600 10 345 1 65 0 929 331 Co 148 7
258. tion 3 7 Data Collection This section describes the main procedure for data collection and first data treatment NOTE Ensure that the detector cannot be hit with the primary beam by using a beam stop or suitable goniometer angles Use one of the following methods to collect data 3 7 1 Scan Method 1 Left click Collect Scan and 1 1 SingleRun to collect one or more frames while rotating one goniometer axis in step scan continuous or oscil lation mode 1 2 MultiRun to run several SingleRuns 1 3 gt MultiTarget to perform one SingleRun on many sample locations 1 4 CoupledScan to collect a raw spec trum in conventional Bragg Brentano geometry where 2 theta and omega are coupled in a 2 1 ratio NOTE Refer to M86 Exx008 GADDS Software Reference Manual for details on these scan options NOTE All data for these scans are saved and all of the corrections are applied automatically Frames are named using the job name run number and frame number with the file exten sion gfrm Frame series get the same job name and run number M86 E01007 Basic System Operation GADDS User Manual 3 7 2 Add or Rotation Method 1 Left click Collect gt Add to collect data at fixed goniometer angles or Collect gt Scan gt Rotation to collect one frame while rotat ing the phi axis with constant rotation speed Refer to the GADDS Software Ref erence Manual for details on these scan options
259. tion System 4 1 15 Jopyr 1997 98 Bruker OG x Elle Edit Collect Process Analyze Peaks Special User Help Spatial Calibration frames 0512_006 _br 02 09 99 13 56 03 Created 8 98 Mag Quai 0 Omega 50 000 width SS Counts 193723 Time s 900 00 121 Distance 6 000 size 512 111 Frame was taken at 2 Theta 50 000 101 Omega 50 000 Phi 286 44 Chi 90 000 x 11 334 Y 7 995 z 1 781 Aux 6 877 Distance 7 460 FloodFld LINEAR Spatial test 512x512 Hv Off Figure 3 8 Blue spotted grid M86 E01007 GADDS User Manual Basic System Operation NOTE Though the X ray spots still appear on the screen s background they are of no concern at this moment The grid is a scaled down repre sentation of the X ray spot pattern to provide space for the X Y graph 5 Check that all spots are present except for those along an edge and form the grid and that no stray spots or jagged lines exist If there are too few or too many spots left click Process gt Spatial gt Reprocess and enter the output filename Then increase the threshold if too many spots exist or decrease it if too few spots exist Press OK A new grid appears NOTE As a starting point when adjusting the threshold we recommend a threshold of 4 NOTE You might have to repeat the reprocess ing step 4 for threshold optimization M86 E01007 Basic System Operation GADDS User Manual 3 5 System Calibration Two methods are availa
260. tion system for combinatorial screening M86 E01007 2 55 System Configuration GADDS User Manual Figure 2 28 shows the retractable knife edge The knife edge tilt angle is adjusted with the adjusting knob to form a parallel gap between the knife edge and the sample surface The size of the gap is adjusted through the micrometer Figure 2 28 The retractable knife edge and the tilt and gap adjustments 2 56 M86 E01007 GADDS User Manual System Configuration The function of the knife edge in the extended position is shown in Figure 2 29 04 and 05 are the incident and diffracting angles respectively and 6 is the gap between the knife edge and the sample surface The knife edge collimates the X ray beam for low angle diffraction Parts of the primary X rays are blocked by the knife edge so they will not reach the adjacent cells on the other side of the knife edge right The dif Figure 2 29 The knife edge defines the area of diffraction fracted X rays from the adjacent cells before the knife edge left are also blocked by the knife edge Therefore only the diffraction from the defined area S can reach the detector The knife edge can also prevent the direct beam from hit ting the detector f f f j j f j j f j f j f j f j f f j M86 E01007 System Configuration GADDS User Manual The relationship between the size of the dif fracted area S and
261. to y to avoid confusion with the goniometer angle y The y angle actually defines a half plane with the X axis as the edge referred to as y plane here after Intersections of any diffraction cones with a y plane have the same y value The conven tional diffractometer plane consists of two y planes with one y 90 plane in the negative Y side and y 270 plane in the positive Y side y and 20 angles form a kind of spherical coordi nate system which covers all the directions from the origin of sample goniometer center The y 20 system is fixed in the laboratory systems X Y Z which is independent of the sample ori entation in the goniometer This is a very impor tant concept when we deal with the 2D diffraction data As mentioned previously the diffraction rings on a 2D detector can be any one of the four conic sections circle ellipse parabola or hyperbola The determination of the diffracted beam direc tion involves the conversion of pixel information into the y 20 coordinates In the GADDS system the y and 20 values for each pixel are given and displayed on the frame Users can observe all the diffraction rings in terms of y and 20 coordi nates with a conic cursor disregarding the actual shape of each diffraction ring M86 E01007 Introduction and Overview GADDS User Manual 1 3 8 Sample Orientation and Position in the Laboratory System In the GADDS geometric convention we use three rotation angles t
262. tor control Table 2 29 HI STAR detector resolution Mode Sample to Detector Pixel Size Resolution Distance Microns 1024x1024 30cm 105 0 02 1024x1024 15cm 105 0 04 1024x1024 6cm 105 0 09 512x512 30 cm 210 0 04 512x512 15cm 210 0 08 512x512 6cm 210 0 17 Figure 2 14 illustrates the cross section of the proportional chamber X ray Figure 2 14 Cross section and work principle of area detector The chamber is filled with a Xe methane gas mixture pressurized to approximately 4 atmo spheres The window is 80 transparent to 8 keV radiation and permits pressurized opera tion When an X ray photon enters the detector it interacts with the Xenon near the front win dow ionizing the gas and creating a cloud of electrons An electric field accelerates these electrons from the near window region through a drift region The detection grid consists of plane of fine anode wires located between two cathode planes of very fine pitched wires The electron cloud passes through the first cathode and is amplified by a factor of 2000 as it is col lected at the anode wire surface Analog signal processing electronics located directly behind the detector produce very low noise signals permitting high spatial resolution 200 um to be achieved at low charge gains of 2000 The position decoding circuit PDC con verts the analog signals from the detector into digital values represen
263. transmission The analytical method is based on the absorption coefficient and the sample thickness The first method is imple mented in many ODF programs while the sec ond is implemented in GADDS Keep in mind that the absorption coefficient of a material depends on the wavelength of X rays in use Also the units of the absorption coefficient and the thickness must be consistent e g cm and cm Typically if the absorption is less than 10 it can be ignored except if extremely accurate ODF results are desired If the density and chemical composition are unknown a method of selective integration and intensity scaling can be used as follows 1 When collecting data for this method break the frame sequence by a least one frame number e g 001 072 075 146 There should be a separate sequence for each o value used during pole figure data collection as previously determined using POLE FIGURE SCHEME 2 POLE FIGURE PROCESS each series of frames separately with the same 20 range but different y ranges Set the y ranges based on the fall off in the integrated inten sity observed using PEAKS INTEGRATE 20 This intensity fall off may be due to sam ple absorption or shadowing There should be a small e g 0 1 gap left between the specified y ranges They should not overlap This is done to enable the different seg ments of the pole figure to be properly scaled before merging Save the individual segments of the pol
264. ts Young s modulus E and Poisson s ratio v or the macroscopic elastic constants 1 7 S 1 v E and 8 v E Then we have Pj 0j P12 012 P13 013 P5505 P23 O23 P33 033 In sinOg sino 6 3 where Zar W fi V 3sofi S itis Pij Za W fii Sofi ifizj The anisotropy correction can also be included in the X ray elastic constants 12S hkl and S4 hkl to replace the macroscopic elastic con stants 2S and S4 The equations for calculat ing X ray elastic constants are 5 So hkl S Z Sal 3 0 2 T hk A Si hkl S4 1950 2 T hkl A nek ke Fh T hk h k P A 5 ARx 1 3 2ARX 6 4 The factor of anisotropy Ap is a measure for the elastic anisotropy of a material Values of Ary for the most important cubic materials are given in the following table additional values may be taken from literature Materials Anx Body centered cubic bcc Fe 1 49 base materials Face centered cubic fcc Fe base 1 72 materials Face centered cubic fcc Cu base 1 09 materials Ni base materials fcc 1 52 Al base materials fcc 1 65 The values of Any have to be given by the user in the calculation settings dialog For most com monly measured biaxial stress an approximate 20g will introduce a pseudo hydrostatic stress component Opp The equation becomes 1 2v sind D41941 P1209 42 D22025 E PRS m Sino 6 5
265. ubregions I5 Ware so the DIFFRACP us STRESS software is Normalize intensity 5 bin normal z I Reprocess only not necessary Follow these steps to process RPM and evaluate the stress data in GADDS Lineshape CE TRE I7 Fit Katpha2 1 Load or open the first frame For example Background fit Both 7 Cutoff 00 z if a set of 7 data frames strsnom 000 006 is used for stress evaluation open the first ou frame strsnorm 000 Figure 6 15 Input an m epe m appropriate High counts value so the dif Young s mod 210000 Poisson s ratio 0 28 Arx ino fraction ring and background region are visi Phi oo Psi 00 Stress Units MPa ble 0200 BEA 08 Figure 6 16 Parameter input menu for stress analysis using Quadrant Fut Low counts High counts z 2D method fae 2theta start lower 20 of conic region 204 A c meena E 2theta end upper 20 of conic region 205 Autoincrement l Preserve Graphics Use orientation in header I Display associated video image Chi start lower X of conic region R Chi end upper y of conic region Normalize intensity 3 for solid angle Figure 6 15 Open file menu of GADDS Step size 20 step size in the integrated profile data default 0 1 choose smaller value for sharper peak 6 22 M86 E01007 GADDS User Manual Residual Stress of Sub regions n Choose the number 3 to 64 of data points in the selected diffraction ring Peak 2T or d Input the
266. unctions have different mathematical properties concerning the addition properties of their FWHMs Gaussian profiles subtract in quadra ture as B2 U2 S2 BRN N CO LA oa while Cauchy profiles subtract linearly B U S where Bis the corrected FWHM for use in the Scherrer equation and U and S are the FWHMs of the unknown and standard peaks respec tively The above results can be derived using the Fourier convolution theorem with the differ ent function types Bear in mind that other pro file shape functions do not have the same additive properties of their FWHMs Usually Cauchy profiles are used for two dimensional detector work but the beam profile is Gaussian The smaller the crystallite size the closer the values obtained from the Scherrer equation for the Cauchy and Gaussian profile shapes will agree For example assume a sample has a dif fraction line at 30 20 and a line width of 2 83 and that a standard LaBg pattern has been mea sured with a line width of 0 09 This would yield crystallite sizes of 29 with a Gaussian fit and 30 with a Cauchy fit Now assume the same unknown has a line width of 0 26 This would produce crystallite sizes of 348 with a Gauss ian fit and 545 with a Cauchy fit Figure 7 2 shows the corrected full width at half maximum B computed from the Scherrer equation as a function of crystallite size t and 20 value M86 E01007 Crystal Size GADDS User Manual Table
267. use with the helium beam path is approximately 15 30 cm Before attaching the helium line you may mount a user supplied bubbler a water filled U shaped glass tube to the bottom gas port with 1 16 inch rubber tubing This device helps regulate the gas pressure and gives a visual indication of the flow rate 7 Attach the helium line to the top port Use the lowest pressure setting on the gas cylin der s regulator Failure to do so may cause the front cone to be propelled into the colli mator support 8 Though not a critical parameter increase the helium s flowrate slowly watching for bulging of the front Mylar window Signifi cant bulging indicates too high a pressure and too high a flowrate Typical purge rates are in the range of 100 500 cc min Once the cone has been initially purged of air elapsed time typically 30 60 min a lower flowrate may be maintained You may experimentally determine the required purge time as a function of the specific flow conditions by collecting frames at intervals and observing the decrease in background scatter with time If the SAXS beam stop attachment is to be used with our high temperature attachment we rec ommend operating the heater without its shroud Otherwise the plastic shroud material will contribute undesirable scatter M86 E01007 GADDS User Manual Small Angle X ray Scattering 9 2 2 SAXS System Adjustment and Calibration Selecting a Collimator Th
268. used to denote a diffracted beam Reflection Mode The diffraction condition that the diffracted beam exits from the same surface that the incident beam strikes on Sample Coordinates A rectangular coordinates fixed on the sam ple S4 S2 and S3 In a typical setup S4 and S lie on the sample surface and Ss is the normal of the sample surface Sample Orientation Sample orientation is determined by the three rotation angles xg and 9 Sample Position Sample position is determined by the three rotation angles c x and 4 and the three translation coordinates X Y and Z Sample Stage A device in a diffractometer to hold sam ple s and maneuver the sample orientation and translation The typical sample stages used in GADDS are fix chi 2 position chi XYZ stages and 4 circle cradle Sample Translation Sample translation is achieved by moving sample along the three translation coordi nates X Y and Z 18 10 M86 E01007 GADDS User Manual Nomenclature and Glossary Small Angle X ray Scattering SAXS The study of matter by analysis of the dif fraction of X rays with diffraction angles smaller than a few degrees that is less than 1 degree for copper radiation Spatial Correction A procedure to build and maintain a position table which corrects raw X Y positions of detector events The spatial correction is done by collecting a brass fiducial plate image at a specific detector di
269. within a script file you are calling a nested script file The primary script file is a first level script and it may call second level nested script files Script files may be nested up to three levels deep Re entry into an already opened script file is not allowed that is a sub level script file cannot call an upper level script file M86 E01007 10 23 Script Files GADDS User Manual Example For three different samples you collected an entire frame series of 72 frames and then noticed that the configuration settings were incorrectly set The wavelength distance and beam centers were erroneous You need to cor rect the frame headers for each frame in the frame series This task is ideally suited to using a 3 level nested script file The first script UpdateSamples slm would look like UpdateFrames Corund0 UpdateFrames Corundl UpdateFrames Corund2 The second script UpdateFrames slm would look like UpdateHeader 1 000 UpdateHeader 1 001 UpdateHeader 1 071 The third script UpdateHeader slm would look like LOAD 1 USE_CONFIG SAVE 1 To execute you would enter UpdateSamples GADDS executes scripts one line at a time If the line is a nested script command the entire nested script file must be executed and com pleted before GADDS continues with the next line of the original script file The first script UpdateSamples calls the sec ond script UpdateFrames with
270. xisting spatial correction Note that the field after Spatial in the main win dow is set to linear 2 Left click Process gt Spatial gt New The Options for Process Spatial New window appears Options for Process Spatial New x Max seconds Em Max counts fi 50000 Max display counts 7 M Realtime display Y N Output filename fi 024 015 ix Io sigmas spot threshold 8 0 M Open close shutter Y N Figure 3 6 Options for Process Spatial New window NOTE The total counts collected at this time will NOTE The GADDS software will suggest a be less than for the flood field data collection default output filename as shown in Figure 3 6 due to the brass plate Do not change the filename 3 Set identical parameters as for the flood field data collection 3 10 M86 E01007 GADDS User Manual Basic System Operation 4 Press OK to start data collection and collect one frame The spots in Figure 3 7 appear on the screen during measurement and rep resent the rays of light transmitted through the holes in the brass plate During this time the software calculates centroid posi tions for each spot ray from which later X Y calculations will be made for analyzing substances N GADDS General Area Detector Diffraction System 1 19 Copyr 1997 98 Bruker File Edit Collect Process Analyze Peaks Special User Help Spatial Calibration frames 0512_006 _br 02 09 99 13 56 03 Created 12 18 98
271. y eds Small Angle X ray Scattering Academic Press New York 1982 A Guinier G Fournet C B Walker and K L Yudowitch Small Angle Scattering of X Rays John Wiley New York 1955 R W Hendricks The ORNL 10 Meter Small Angle X ray Scattering Camera J Appl Cryst 11 15 30 1978 10 11 12 13 T C Huang H Toraya T N Blanton and Y Wu X ray Powder Diffraction Analysis of Silver Behenate a Possible Low Angle Diffraction Standard J Appl Cryst 26 180 184 1993 H P Klug and L E Alexander X ray Diffraction Procedures for Polycrystalline and Amorphous Materials 1st ed John Wiley New York 1954 O Paris P Fratzl F Langmayr G Vogl and H G Haubold Internal Oxidation of Cu Fe Small Angle X Ray Scattering Study of Oxide Precipitation Acta Metall Mater 42 2019 2026 1994 Proceedings of the VIIth International Confer ence on Small Angle Scattering Leuwen J Appl Cryst 24 413 877 1991 M86 E01007 GADDS User Manual Script Files 10 Script Files Scripts sometimes called macros are a very powerful feature of the GADDS software A script is a series of GADDS commands that you group together as a single command to accom plish a task automatically That is instead of manually performing a series of time consum ing repetitive actions in GADDS you can create and run a single script in effect a custom com mand that accompl
272. y in a small fraction of the time it takes a conventional texture diffractometer with a scintil lation detector to collect a single pole The HI STAR detector is a gas filled multiwire proportional counter It is a true photon counter which makes it extremely sensitive for weakly diffracting materials The extremely low back ground of the HI STAR makes it ideal for appli cations requiring long measurement times tens of minutes to hours such as small angle X ray scattering and microdiffraction M86 E01007 GADDS User Manual Introduction and Overview 1 5 References 1 B D Cullity Elements of X Ray Diffraction 2nd ed Addison Wesley Reading MA 1978 R Jenkins and R L Snyder Introduction to X Ray Powder Diffractometry John Wiley New York 1996 A J C Wilson International Tables for Crystal lography Kluwer Academic Boston 1995 Philip R Rudolf and Brian G Landes Two dimensional X ray Diffraction and Scattering of Microcrystalline and Polymeric Materials Spec troscopy 9 6 pp 22 33 July August 1994 J Formica X Ray Diffraction In Handbook of Instrumental Techniques for Analytical Chemis try edited by F Settle Prentice Hall New Jer sey 1997 N F M Henry H Lipson and W A Wooster The Interpretation of X Ray Diffraction Photo graphs St Martin s Press New York 1960 H Lipson and H Steeple Interpretation of X Ray Powder Diffraction Pattern
273. y y may be used alterna tively is a diffraction profile analogous to the data collected with a conventional diffractome ter Figure 6 4 shows the relation between a 2D detector and a conventional detector The dif fraction profiles at y 90 and y 90 270 on the 2D detector are equivalent to the diffraction profiles collected in the conventional diffracto meter plane Therefore you can use diffraction profiles at y 90 and y 90 on a 2D detector to imitate a conventional diffractometer In theory it has been proved that the conven tional fundamental equation is a special case of the 2D fundamental equation In the same way a conventional detector can be considered as a limited part of a 2D detector Depending on the specific condition you can choose either theory for stress measurement when a 2D detector is used If the conventional theory is used you have to get a diffraction profile at y 90 or M86 E01007 Residual Stress GADDS User Manual y 90 this is normally done by integrating the data in a limited y range The disadvantage is that only part of the diffraction ring is used for stress calculation When the new 2D theory is used all parts of the diffraction ring can be used for stress calculation Figure 6 4 Relationship between diffraction ring on 2D detectors and 1D detector on diffractometer plane 6 8 M86 E01007 GADDS User Manual Residual Stress 6 1 4 Advantages of Using 2D De
274. ylindrical tube with a smooth inner surface that may be used in place of a pinhole collimator The monocapillary is a product of capillary X ray optics which is based on the concept of total external reflection That is X rays can be reflected by a smooth surface when the angle of incidence is smaller than the critical angle 8 The critical angle is a function of the wavelength and materials The shorter the wavelength the lower the critical angle When X rays are reflected by the inner surface of a capillary at a grazing angle smaller than the crit ical angle of the capillary materials X rays are reflected with little energy loss The transmis sion efficiency depends upon the X ray energy the capillary materials reflection surface smoothness the capillary inner diameter and incident beam divergence The Kg radiation having higher energy than K has less trans mission efficiency For typical capillary materi als the critical angle is about 0 2 for Cu K radiation For GADDS systems the monocapillary trade name MonoCap is mounted inside a steel tube The tube is of the same design as the one used for the pinhole collimator Therefore it is easy to switch between pinhole collimator and monocapillary The monocapillary performs the following main functions e tcollimates the beam spatially to a variety of beam sizes for different applications You have a choice of monocapillary sizes from 1 0 mm down to 0 01 mm e
275. zed axis Phase ID with powder imme Zeami Xg 54 74 y 35 26 sample in capillary Max sample load 1 kg lt lt usually used Polymer applications Sphere of confusion with a goniometer head Texture and stress for 50 um with XYZ translation small samples Huber 4 Motorized y X Y and Microdiffraction 2 Position Motorized 6 axis The same as fixed chi Circle Z axes Phase ID Xg 54 74 and 90 y stage at cg 54 74x Eulerian 3 lt xg lt 94 Stress analysis 35 26 and 0 cg 90x is suitable for Cradle 0 lt o Texture analysis lt lt usually used reflection mode diffrac 75 mm X 75 mm X Y mapping with a goniometer head tion stress tensor 75 mm Y 75 mm High resolution with XYZ translation and microdiffraction 1 mm Z 12 mm diffraction XYZ Motorized X Y and Z Microdiffraction Max sample load 5 kg axes Phase ID Sphere of confusion Fixed xg 90 y 0 Stress analysis lt 50 um Fixed 0 no rota X Y mapping tion Multi target screening X Y and Z travels 50 mm Max sample load 10 kg Position accuracy 12 5 um Repeatability 5 um 2 30 M86 E01007 GADDS User Manual System Configuration 2 4 Sample Alignment and Monitor Systems Sample alignment systems assist you in posi tioning the sample into the instrument center and in monitoring the sample s state and posi tio

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