Model SMM-701G HTS NDE System
Contents
1. b T Shielded E rt e First cooling time 15 min Time to heat above Te 10 sec Cooling after heating 15 min 1 10 100 1000 10000 Frequency Hz Gradient resolution vHz Figure3 G40810 White Noise measured at 100 Hz 40 fT cmNHz noise at 1 Hz 140 fT cmNHz 2 3 1 1 Measurements in a non superconducting shield Additional measurements were made at Tristan in a non superconducting mu metal shield These tests determine the bandwidth and voltage transfer function for each device Operation at various gains and ranges are verified using the customer s electronics Testing is done using Hewlett Packard 34401 A DMM 35665A dynamic signal analyzer and other appropriate test equipment Typically multiple average FFT s are taking using a Hanning window to give the spectra shown below Because of the local environmental noise even inside a mu metal shield these measurements show different noise levels than the results shown in Figure 3 77 vs 40 fT cmNHz in a superconducting shield It should be noted that HTS SQUID sensors typically show a 10 30 variation from device to device dB Mag 18 256Hz AVG 160 182 Figure 4 G40810 bandwidth measured at Tristan These tests were not to demonstrate ultimate performance in a remote environment but to verify proper operation of the SQUID electronics higher noise is typical of unshielded Page 5 of 39 op2. 10 3 2 3 Cooling the system from room temperature 11 NORMALT OPERATION cir ee 12 4 1 REFILLING THE DEWAR WITH LIQUID NITROQGEN eR 12 HLS Sensor Cool Downi and O duo etes thal a E teles ia aed 13 4 2 DEWAR WARMSUPPROGCEDIUR E ice tme esa etae es En eco deti 13 4 3 SAFETY PRECAUTIONS FOR HANDLING CRYOGENIC LIQUIDS t7 14 4 3 4 Extreme Cold Coyer Eyes Exposed Skin tei ide b S LR Aes 14 43 2 KEEP AIR AND OTHER GASES AWAY FROM LIQUID HELIUM cnm 14 43 5 KEEP EXTERIOR SURFACES CLEAN TO PREVENT 15 43 4 PRESSURE RELIEF DEVICES MUST BE ADEQUATELY 15 REEPTEOQUIPMENT AREA VVEEEWENTIEATED i duerme ies 15 DATA ACQUISITION AND SCANNING SOFTWARE eee eee eoo reete eene oett teet aae e sete teet haee esee e e eee ede 16 5 1 BLOCK DIAGRAM re E copa ne ren cL ey 16 5 2 DOTAR ate dt vee seitens 16 DM ADC FOUL TIE J sce bad sence 18 SV MES s IM 19 5 3 DPEEDZADIUSTNIENTE A ioi e Me yet M DEM M Me SiS 19 5 4 TOF MA
3. or otherwise without prior written permission of Tristan Tristan reserves the right to change the functions features or specifications of its products at any time without notice Any questions or comments in regard to this product and other products from Tristan please contact Customer Service Tristan Technologies Inc 6185 Cornerstone Court East 106 san Diego Ca 92121 Phone 858 550 2700 FAX 858 550 2799 info tristantech com http www tristantech com Page iv of iv 1 WARRANTY Tristan Technologies Inc warrants products to be free from defects in material and workmanship Obligations under this warranty shall be limited to replacing repairing or giving credit for the purchase price at Tristan s option of any instrument returned shipment prepaid to its factory for that purpose within one year of delivery to the original purchaser provided prior authorization for such return has been given by an authorized Tristan representative This warranty shall not apply to any instrument which Tristan s inspection discloses to have become defective or unworkable due to abuse mishandling misuse accident alteration negligence improper installation or other causes This warranty shall not apply to any instrument or component not manufactured by Tristan When products manufactured by others are included in Tristan s equipment the original manufacturer s warranty if any is extended to purchaser to th
4. Display and 3D Scan Display Page 19 of 39 gt main vi ACT HJ Successful E initialization of 2 table SMM 701 Tristan Technologies Inc MAE San Diego CA 5 Tue 30 Sep 2003 at 16 45 43 4 h 1 System Initialization mode has been completed Magnetic Field Imaging System www tristantech com Proceeding to System Operation mode F SQUID Acquire Excitation Move 5 File 2 Grad Color Input Range measure time ms 2 1000 1 3 7 gt Lighting settle time ms 1 100 sample rate Hz 100k Lat i re Lon gt 2 00 9 il 0 00 0 Fill Color 5 3 00 9 4 00E 9 7 E p 5 00E 9 o Eo eT 1 00 0 D Levels 10 n Y 1 00E 0 71 Sample 0 100 ad HAN 1 Z max 0 00 0 Zmin 0 00E0 Z delta 0 00E4 0 x mm Y mm 2 mm J User Notes STOP 5 4 1 User Log The User Log is a tool which displays and logs software commands for use in documenting scanning experiments see Figure 185 The logs are automatically saved in the C MagScan System_Log directory in separate folders for the month and year of the log A separate log is kept in the folders for every time the software is run and is automatically named by the date and time of the software start When the box to the right of the user log display is checked the displa
5. EEEEGTSIN 31D SOCAN EE BENE Ret Da rios Ne perc 29 FIGURE 34 POINTSIN O D SCAN DISPLAY dente bd ash odes 29 FIGURE 35 SURPACECONTOURSIN 2D SCAN DISPEASCSi ioci eet inis etie 30 FIGURE 36 SURFACE NORMALS IN 2D SCAN DISPLAY no eure sane voa soe Delect 30 FIGURE 37 SAMPLE VS REFERENCE IN 3D SCAN DISPLAY PUE dT 3l FIGURE 38 FACE X Y PLANE INS D SCAN DISPLAY cioran pad tul tratta e botte UNE 32 FIGURE 39 DB DXSCANOPEMAGNELIC DIPOEE a 33 FIGURE 40 MAGNETIC FIELD GRADIENT DB DX GENERATED BY A MA CURRENT WIRE ORIENTED IN THE Y DIREC II J NR T HC 33 FIGURE 41 PEU CG ED 38 FIGURE 42 SIBICAIEPUENDICATOR COPORS Sq ds uu MID P MD A E TE II P PI RE 38 Page iii of iv TABLE OF TABLES REPORT AEn reo mn Ma M E Em UE MED M EE E 8 Tristan Part Number 3000 120 Revision Record Dae 7 September 07 2003 Initial Release September 27 2004 Modified for 7010 1998 2004 by Tristan Technologies Inc All rights reserved No part of this manual may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording
6. SQUID sensor reaches room temperature dry the body of the SQUID sensor Probe observing ESD precautions and then store with desiccant When testing the SQUID cables at room temperature limit the current by using a manual range on a low current digital multi meter Do not use the auto range function of the digital multi meter Select the KO range Do not heat the SQUID using HEAT button on the Tristan model iMC 303 SQUID Control Electronics or equivalent heating circuit at when the SQUID sensor is at room temperature Ship the SQUID sensor with the shunting plug attached and in a closed container with desiccant inside NEVER allow the SQUID to sit in a sealed dewar with water condensed on the bottom WARNING MOISTURE DAMAGE DUE TO FAILURE TO FOLLOW THESE INSTRUCTIONS WILL VOID THE WARRANTY Page 39 of 39
7. Table 1 Dewar Test Report Results The dewar gap is defined as the distance between the inner cold tail and the bottom of the outer room temperature tail Because of the 0 3 thermal contraction of G 10 from room temperature to 77 K the inner tail length will shrink and increase the tail gap 075 2 0 20 2 0 4 535 Um 5 364 _ 5 000 3 001 2 143 O RING we 44 40 UNC 2B 1 ONI T A 10 900 3 438 Figure 5 model NLD 530 dewar dimensions in inches 2 3 4 Insert and sensor orientation Figure 6 NLI 53G Probe The probe is designed to allow the sensor to be oriented in either the dBz dx or dB dz direction Normally the system is delivered with the sensor in the horizontal dBz dx or dBz dy orientation Figure 7 Figure 7 SMM 701G probe in the horizontal orientation Page 8 of 39 To change orientation horizontal lt gt vertical if the probe dewar is cold follow the warm up instructions in section 4 2 When the probe is warm if there is any rf shielding e g aluminumized Mylar superinsulation carefully remove it assuming you plan to reuse it The HTG 10N SQUID sensor is held on to a semi circular G 10 block by two 2 42 56 x 5 round head G 10 screws the removable block is fastened to the probe cylinder by another two screws Remove them and the semi circular block and re orient the HTG 10N SQ
8. before proceeding Run the TUNE Utility When turning off the system set Bias and Mod and Skew to 096 disconnect the CC 6 composite cable s and then turn off AC power When disconnecting all cables disconnect the 5 pin LEMO connector first then the 10 pin LEMO connector 4 2 DEWAR WARM UP PROCEDURE If the SQUID magnetometer probe is not in the dewar then pouring out the liquid nitrogen or letting the liquid nitrogen evaporate is acceptable However since HTS SQUID sensors will be damaged by exposure to moisture section 7 2 special Page 13 of 39 precautions must be taken when warming up dewars that are being used to cool HTS SQUIDs To prevent exposure to moisture immediately remove the probe and place the probe inside a tight fitting plastic bag to prevent excessive condensation of moisture sure that a desiccant is inside the bag When the probe and sensor has warmed up to room temperature place the probe in a moisture free container 9 a dry box The sensor can be removed from the probe or the stored attached to the probe If the probe and SQUID sensor are kept together the dry box dimensions must be greater than 10 cm 4 diameter x 46 cm 18 to able to accommodate the probe After removing the probe turn the dewar upside down to pour out the remaining nitrogen Be sure not to pour the liquid nitrogen on anything that could be damaged Then let the dewar warm up to room temperature leave the neck tu
9. dx or dBz dy orientations Figure 7 3 2 2 Connecting LEMO connectors Page 10 of 39 If the SQUID sensor is not attached to cryogenic insert remove any shunting cap that is attached Figure 9 LEMO shunting connector Do not twist the cap when removing or attaching it Otherwise the LEMO connector pins can be sheared off When inserting the shunting cap or connectors be sure that the red spot on the female connector is lined up in the center of the slot or its corresponding red spot on the male connector Figure 10 correct connector alignment Do not twist or attempt to force the connector as that can cause the pins to break Figure 11 Figure 11 bent pins from twisting connector during improper attachment 3 2 3 Cooling the system from room temperature Install the funnel in the neck of the dewar Fill the dewar by slowly adding LN until full Remove the funnel and slowly lower the probe into the dewar Avoid freezing the o ring and pump out fitting When fully lowered secure the probe to the dewar with the proper hardware Remove the fill tube plug and install the funnel into the fill tube Slowly pour into the funnel until LN2 vents from the vent port Wait a moment and then add more LN until it again vents from the vent port Repeat this sequence until adding causes immediate venting The dewar is now filled Remove the funnel and replace it with the fill tube plug Leave the vent port
10. mm 0 00 0 00 75 00 PosLimit mm 75 000000 75 000000 38 000000 NegLimit mm 75 000000 75 000000 75 000000 Center mm 0 00 0 00 38 00 N 25 25 1 Step mm 1 00 1 00 1 00 MotorEnable TRUE DAQ NumChans 2 CoilCalibration fT V 2 00E 9 1 00E 0 ExcitationCalibration fT V 8 47E 7 MeasureTime ms 998 SettleTime ms 100 InputRange V 10 0 10 0 HighPassFilter 0 LowPassFilter 0 Gain 1 Offset 0 Slew 0 ExcitationFreq Hz 0 000000 Amplitude fT 1 00E 9 Decimation FALSE ExcitationAmplitude fT 1 00E 9 Misc FLL resource 1 DataRootPath C MagScan Experiment_Data TemporaryRootPath C MagScan Temporary 6 TROUBLE SHOOTING The greatest obstacle to SQUID measurements is external noise sources Metallic shielding can minimize external noise act as a low pass eddy current shield In the case of HTS SQUID sensors the use of high permeability mu metal shields such as the Tristan MS 830 can significantly attenuate external field variations This assumes that any electrical inputs to the experimental region have been appropriately filtered Powerline or microprocessor clock frequencies can severely degrade performance Unfortunately if external objects are to be measured external shields are not appropriate However external shields are helpful in verifying proper operation of the SQUID system and electronics When measuring external fields the SQUID magnetometer must operate in an environment the
11. 00 3200 000000 1250 000000 MotorSet steps rev 3200 3200 3200 MotorVelocity 50 000000 MotorAccel 20 000000 ResetPos mm lt 9 5125 8 2812 15 5000 InitPos mm 0 00 70 00 5 00 PosLimit mm 75 000000 75 000000 38 000000 75 0000007 75 000000 75 000000 Center mm 0 00 0 00 38 00 572 Oy Step mm 1 00 1 00 1 00 MotorEnable TRUE DAQ NumChans 2 CoilCalibration 2 50 8 1 00 0 ExcitationCalzsbratiou tfIlI V s8 4TETJ7 MeasureTime ms 998 SettleTime ms 100 InputRange 10 0 10 0 HighPassFilter 0 LowPassFilter 0 Gain 1 Offset 0 Slew 0 ExcitationFreg Hz 0 000000 Amplitude 1 00 9 Decimat Lon FALSE ExcitationAmplitude 1 00E 9 Misc FLL resource name COM1 DataRootPath C MagScan Experiment_Data TemporaryRootPath C MagScan Temporary 5 3 Speed Adjustment The speed can be adjusted Go to C MagScan Configuration ini Current ini is the most recent settings and Default ini is the factory default Change the row for MotorVelocity There is no absolute position feedback so if you make it too high it will miss steps and have an inaccurate position We do not recommend speed settings above 100 5 4 The Main Window At the end of the software initialization process the Main window remains see Figure 174 The Main window is broken down into five different sections namely the User Log Parameter Input Time Display Status
12. D Scan Display oelecting Point removes the surface smoothing from the display and shows the point of data that were acquired see Figure 34 4 color WX Figure 34 Points in 3D Scan Display Page 29 of 39 Surface Contours may be added to surface for better perception of the 3D surface see Figure 3532 The number of contour levels on the graph is selectable by changing the Level value 4 T 2 t Figure 35 Surface Contours in 3D Scan Display Surface Normals may be displayed as well see Figure 363 ij color Anode MX JJ SurfaceNormal Jf Sampe Figure 36 Surface Normals in 3D Scan Display Page 30 of 39 When data different data sets are loaded as sample and reference two can toggled between the Sample and Reference for purpose of comparison see Figure 3 4 Additionally the Sample vs Reference setting subtracts the reference amplitude from the sample amplitude for each measured value of X and Y to display the differences between two data sets For use in noise reduction a series of data sets should be collected without a sample on the scanning stage to be used as the reference Then a series of data sets can be taken with samples In the sample vs reference mode the average background and environmental noise will be significantly reduced z Grad dj Color Lighting Lat mmmn L
13. ID electronics and data acquisition hardware requires an area of 50 cm x 100 cm 2 x 4 If the scanning stage is mounted on a table or desk be sure that the platform is rigid Movement of the SQUID sensor relative to the Earth s magnetic field can cause vibrationally induced noise Do not put the scanning stage on a metal table or desk Placing the SQUID sensor near metal especially steel will couple magnetic field gradients into the SQUID sensor and significantly increase sensitivity to environmental noise The SQUID may not be able to hold lock in the presence of large gradients Likewise placing the system directly on a concrete floor that has rebar in it may couple gradients into the SQUID sensor To minimize the pick up of 60 Hz the SMM 701G should be placed as far from powerlines and distribution boxes as possible To reduce the influence of the scanning platform it may be worthwhile to mount the sample on a nonmagnetic platform 3 2 1 SQUID Sensor Orientation The NLD 530 dewar is glued GE 7031 varnish to a rectangular mounting plate that mounts on the z stage extension arm This is to ensure proper orientation of the dewar and probe The probe has indicating marks to indicate the x direction The scanning stage motors are labeled to indicate x y and x directions The NLI 51G probe has four mounting holes on the top plate that allow it to be rotated in 90 increments This allows the user to set the SQUID sensor to be in the dBz
14. M WHICH ARE NOT COVERED BY THE TRISTAN TECHNOLOGIES LIMITED WARRANTY SHOULD THE MOTION NEED TO BE STOPPED AT ANY TIME FOR AN EMERGENCY TURN OFF EITHER THE AC POWER OR ENABLE SWITCHES ON THE FRONT OF THE NATIONAL INSTRUMENTS MID 7604 MOTION CONTROLLER When the motor positioning sequence concludes the Motor Position Initialization Complete prompt appears see Figure 163 Once the OK button is clicked the software is ready for use Motor initialization complete or motor driver is powered off Figure 16 Motor Position Initialization Complete 5 2 1 Default ini file Motion MotorEnable TRUE MotorConv steps mm 3200 0 3200 0 1250 MotorSet steps rev 3200 3200 3200 MotorVelocity 50 0 MotorAccel 20 0 BeserPosimm 9 5125 9 2812 75 5000 InitPos mm 0 0 0 0 75 0 PosLimit mm 75 75 38 NegLaimrit 75 15 175 Center mm 0 0 389 Step mm 1 1 1 N 25 25 1 DAQ NumChans 2 CoilCalibration tT V 2 56 9 1 ExcitationCalibration f T V 8 47et7 MeasureTime ms 998 SettleTime ms 100 InputRange V 10 10 HighPassFilter 0 LowPassFilter 0 Gain 1 Offset 0 Slew 0 ExcitationFreg Hz 0 00 ExcitationAmplitude 1 9 Decimation FALSE Misc Page 18 of 39 FLLComPort COM1 DataDirectory C MagScan Experiment_Data TemporaryDirectory C MagScan Temporary 5 2 2 Current ini file Motion MotorEnabled TRUE MotorConv steps mm 3200 0000
15. N da rude nd TUER e 21 FIGURE 20 ACQUIRE PARAMETER INPUT OF MAIN WINDOW cecccsecccscccscccsccesccccccusccesccussceusceuscceeceusceusceuecs 22 FIGURE 21 EXCITATION PARAMETER INPUT OF MAIN WINDOW a 22 FIGURE 22 MOVE PARAMETER INPUT OF MAIN ese sese sese esas sense eese senes 23 FIGURE 23 SCAN PARAMETER INPUT OP M AIN WINDOW tutes eiu Pee Renee am Peu ated 24 FIGURE 24 FILE PARAMETER INPUT OF MAIN WINDOW ceceeeeeeeeeeettee hene ene nnne rese ese sese ese ese sese sese ese seen 24 FIGURE 25 DISPLEAY M MAIN WINDOW PTT 25 FIGURE 26 STATUS DISPEAY IN MAIN WINDOW detta toos Pre decre mec Ceuta etta teen oca 25 FIGURE 27 SD SCAN DISPLAS WINDOW 2813 EI P IQ MP eM Por M 26 FIGURE 28 SD ROTATION OF SD SCAN DISPLAY Peto dme e 26 FIGURE 29 ZOOMIN OF SD SCAN DISPLAY oS LM CE OLD DE MU 2 FIGURE 30 ZOONECOUT OF 31D SCAN DISPLA 27 FIGURE 31 PANNING OF SDISCAN DISPEAS gate co Ic E E in pc Deu 28 FIGURE 32 CURSOR ONIN SD SCAN DISPLAY aei eoe mer ue delta bb boa I usu ose tele Une RA 28 FIGURE 33 PAXGHTING
16. NN WINDOW C H 19 PE TEMP C boc cele ads cee fanaa tc acters 20 SE MEE 010 ELITR Tr 21 La 24 SOUS DISD ERREUR 29 DE A NEED 29 5 5 SOFTWARE I MEI E 32 5 6 SAMPDPESCANGS ni simus a EC ndn dnce mess a eae M mdr 32 5 7 PICE TONER NE 33 DEN Data Tle ea E E T E T ES 33 L72 icguutonDardmetebs file GuY entdHllsa ua iuueni teste 34 Page ii of iv 07 SHOOTING Poe 34 6 1 DOC CURRENT SUPPPEIES 52 A l ci I E ELO Pise MEE 35 7 MAINTENANCE eve E Isa v 36 7 1 PEMA R ME 36 Ta HIGH TEMPERATURE SQUID SENSOR 37 7 2 1 Handling for Shipping and or Storing at Room Temperature sss 37 TABLE OF FIGURES FIGURE 1 NIODELISMMSZOlGUICOMPONENTSU Re naw pO 2 FIGURE 2 MASK OF HTG 10N PLANAR GRADIOMETER INPUT COIL SHOWN AT 2X ACTUAL 4 FIGURE 3 G40810 WHITE NOISE MEASURED AT 100 Hz 40 FT CMNHZ NOISE AT 1 Hz 140 FT CMNHZ 5 FIGURE 4 G40810 BANDWIDTH MEASURED AT TRISTAN cccccsscccssccsccesccesccesccesccescceeccusccescces
17. OGIES LIMITED WARRANTY BE AWARE OF THE CONSEQUENCES OF MOVING OR CHANGING THE LIMITS OF THE MOTION BEFORE EXECUTING COMMANDS SHOULD THE MOTION NEED TO BE STOPPED AT ANY TIME FOR AN EMERGENCY TURN OFF EITHER THE AC POWER OR ENABLE SWITCHES ON THE FRONT OF THE NATIONAL INSTRUMENTS MID 7604 MOTION CONTROLLER SQUID Acquire Excitation Move Scan Y osition mm fo mm 10 000 Jio 000 E 000 limit mmn 75 000 75 000 138 000 limit mm 75 000 75 000 75 000 Figure 22 Move Parameter Input of Main Window The Scan tab see Figure 2320 controls the motion of the scanning stage during a measurement For each axis the Center value selects the position of the center of the area to be measured The Step value controls the distance the sample stage moves per step in each axis The N value controls the number of steps taken per axis The motion is carried out in the following order all positions of X are scanned for a given Y then the Y value changes and all positions of X for the new Y value are measured When all positions have been measured for a X Y plane are measured at a given Z then the Z value changes and all positions in the X Y plane for the new Z value are measured The yellow Scan button starts and pauses scans The numerical value to the right of the yellow scan button selects the number of times each position in X Y Z is scanned If the number of scans selected is greater t
18. UID sensor Be careful not to break the multi colored cabling The HTG 10N SQUID sensor should be mounted so that the cabling is arranged as shown in Figure 8 Figure 8 SMM 701G probe in the vertical orientation As mentioned in the vertical dB dz or dBy dz orientation the G 10 mounting block is not needed When in the desired orientation carefully tighten the G 10 screws and replace any superinsulation rf shielding Follow the normal cooldown procedure section 3 2 3 when finished To return to the dBz dx orientation reverse the procedure making sure that the G 10 mounting block is attached to the probe cylinder before mounting the HTG 10N SQUID sensor 2 3 5 Electronics and software See the User s Manual for iMAG HTS Multi Channel dc SQUID System for information on the use of the electronics and software 3 INSTALLATION 3 1 INITIAL INSPECTION All Tristan instruments and equipment are carefully inspected and packaged at Tristan prior to shipment However if a unit is received mechanically damaged notify the carrier and the nearest Tristan representative or the factory in San Diego California Keep the shipping container and packing material for the carrier and insurance inspections If the unit does not appear to be damaged but does not operate to specifications contact the nearest Tristan representative or the Tristan factory and describe the problem in detail Please be prepared to discuss all surrounding circum
19. User s Manual for Model SMM 701G HTS NDE System Tristan Technologies Inc San Diego California USA copyright 1999 2004 Page i of iv 1 2 TABLE OF CONTENTS WARRANTY ic e ca v e p p a NH Ue saecu ud dieci de e n prec te Ue uM SEDE 1 GENERAL aua vea 2 2 1 INIRODUCTION sad ea an Sena ise 2 2 2 SS 2 UDISQOLSVSIOUDTGCODDOBOHIS dcos ed Li cadis 3 2 3 MEASURED PARAMETERS AND FACTORY TEST DATA cen 4 VON MEO TID 4 232 oural Dewar r rameter anche D Lose 8 2 94 JUsertand Sensor 8 23 Blecronics and SO 9 INSTACLA ION ounner 9 3 1 5 UNIO 9 312 REPACKING POR RETURN SHIPMENT oc er ere eee eds 10 344 2 RETURN FROM CUSTOMERS OUTSIDE TEE USA ie elec ceste ie bee eed recentis 10 3 2 INORN DAI INSTAIDDATIONG i eite ste den ii E e aaa tec bes eo dus coepi Dd ict Ms 10 Sd GOOCH SenSOR Or CIA ON o lo pts iN eu eL cd 10 D2 DEMO
20. atus of the system The Channel is always set to a value of 1 because the system contains a single channel of data acquisition The X Y Z values display the current position of each axis of the motion control stages The Scans value is an indicator of the progress of the system as it is running a scanning measurement If one scan is selected and is measuring 100 different positions then the scan value will increase by 0 01 each time a measurement is taken At the end of a measurement the scan value is equal to the number of scans selected To add experiment information to the user log for purposes of documentation select the User Notes button This feature allows the user log to be used as a limited laboratory notebook WARNING if you want to stop the scan process do not press the STOP button press the button When the Stop button is pressed the software will shut itself down After it has done so it is safe to close the main window x mm Y mm 2 mm Channel J 1 1000 4 76 00 Scans NaN User Notes Figure 26 Status Display in Main Window 5 4 5 3D Scan Display The 3D Scan Display see Figure 274 is an analysis tool which can be used in real time with current data or with previously acquired data Amplitude is displated in fT femtoTesla Strictly speaking because the SQUID sensor is a gradiometer the units should be fT cm The fT notation is used for software compatibility with other Tristan SMM scanning SQUID syst
21. be open Turning the dewar upside down will minimize the amount of moisture that may condense inside the dewar If this procedure is used it will be necessary to make sure that any water which condenses in the dewar is removed prior to using the system again This can be done by wiping it out using a rag on the end of a rod or by blowing room temperature air into the tail of the dewar WARNING DO NOT BLOW HOT AIR INTO THE DEWAR AS THIS MAY CAUSE FAILURE OF THE EPOXIED JOINTS 4 3 SAFETY PRECAUTIONS FOR HANDLING CRYOGENIC LIOUIDS The potential hazards of handling liquid helium stem mainly from the following properties WARNING LIQUID NITROGEN IS EXTREMELY COLD THE LOW TEMPERATURE OF LIQUIND NITROGEN AND CONDENSE AND SOLIFIFY AIR DO NOT LET LIQUID NITROGEN BE CONFINED IN A CLOSED SPACE VERY SMALL AMOUNTS OF LIQUID NITROGEN ARE CONVERTED INTO LARGE VOLLUMES OF GAS NITROGEN IS NOT LIFE SUPPORTING 4 3 1 Extreme Cold Cover Eyes and Exposed Skin Accidental contact of liquid nitrogen or the cold gas that results from its rapid evaporation may cause a freezing injury similar to a burn Protect your eyes and cover the skin where the possibility of contact exists Eye protection should always be worn when transferring liquid helium 4 3 2 KEEP AIR AND OTHER GASES AWAY FROM LIQUID HELIUM The low temperature of liquid nitrogen can solidify another gas Solidified gasses and liquid particularly solidified air can p
22. cceusseusccucceussensess 5 FIGURE 5 MODEL NLD 530 DEWAR DIMENSIONS IN 8 FIGURE 6 MEOS URN T m 8 FIGURE 7 SMM 701G PROBE IN THE HORIZONTAL ORIENTATION cccccsccccsecccescccensccescscesccseseseeecseeeceseusesensess 8 FIGURE 8 SMM 701G PROBE IN THE VERTICAL ORIENTATION ccccccccsscccsecccescccesscseuscscesceseseceeecsesecseensesensees 9 FIGURE 9 LEMO SHUNTINGCONNEC TOR a I ORIS fe 1 FIGURE 10 CORRECT CONNBCTOR ALIGNMEBNT eee 11 FIGURE 11 BENT PINS FROM TWISTING CONNECTOR DURING IMPROPER ATTACHMENT 11 FIGURE 12 ADDING LIQUID NITROGEN TO COLD DEWAR 12 FIGURE 13 DATACACOUISTION BLOCK DIAGRAM isso teniente S EcL aan 10 FIGURE 14 INT ALIZATION FILE WINDOW eon 17 FIGURE 15 MOTOR POSITION INITIALIZATION PROMPT cost era tei eb eebeban te coe Tr FIGURE 16 MOTOR POSITION INITIALIZATION eese sese se enses nean 18 FIGURE 17 eI UR M DM REDE 20 FIGURE 18 USERLEOG SECTION OF MAIN WINDOW Pda eno ioct etienne 0 20 FIGURE 19 SOUID PARAMETER INPUT OF MAI
23. e it can be very effective in attenuating rfi As mentioned above significant gradient noise can be introduced if the dewar is positioned near a metal fixture such as a steel filing cabinet or a power distribution box If a planar gradiometer is being tested rotating the gradiometer anywhere from 309 909 can often make a significant change the measured gradient noise During the initial testing be sure that the system is on a sturdy platform A flimsy table may cause motion induced noise Also be sure that the platform or whatever mounting is being used is free of any ferromagnetic contaminants Avoid using conductive metal tables as they can couple in gradient noise 6 1 dc current supplies When generating dc currents avoid the use of any power supply driven by 60 cycle ac current Many current sources have a large amount of high frequency noise in their output This is frequently large enough to prevent reliable operation of the system This will show up as rapid jumps in the output voltage or in the extreme case a steady full scale drift in the output which indicates that the feedback loop is completely inoperative In this situation you will observe that the SQUID s periodic transfer function triangles will be severely degraded or completely unobservable The Tristan model CCS Constant Current Source has a relatively noise free stable current supply The article Constant current supply of 3 ppm stability and resettabil
24. e extent permitted by that manufacturer Tristan reserves the right to make changes in design at any time without incurring any obligation to install same on units previously purchased There are no warranties which extend beyond the description herein This warranty is in lieu of and excludes any and all other warranties or representations expressed implied or statutory including merchantability and fitness for purpose as well as any and all other obligations or liabilities of seller including but not limited to special or consequential damages No person firm or corporation is authorized to assume for Tristan any additional obligation or liability not expressly provided for herein Page 1 of 39 2 GENERAL INFORMATION 2 1 INTRODUCTION This instruction manual contains installation operation and maintenance instructions for the model SMM 701G HTS SQUID gradiometer measurement system supplied by Tristan Technologies Inc The model SMM 701G HTS NDE System block diagram is presented in Figure 1 has been designed and built by Tristan Technologies Inc The system includes the following basic components e Liquid Nitrogen Dewar System HTS SQUID Gradiometer Probe iMAG SQUID Electronics AC Magnet System Sample Motion Control System Data Acquisition System 2 2 SYSTEM COMPONENTS Please check the enclosed packing list carefully when unpacking the equipment to verify that everything is present and undamaged We
25. ems Page 25 of 39 T E e Figure 27 3D Scan Display in Main Window The display may be rotated in any direction see Figure 285 by using the computer mouse to place the cursor on the display press and hold the left mouse button and move the mouse lt Figure 28 3D Rotation of 3D Scan Display Page 26 of 39 Holding down the ALT key of the computer keyboard pressing and holding the left mouse button and moving the mouse allows for zooming in and out of the display see Figure 296 and Figure 307 A a surface Figure 29 Zoom In of 3D Scan Display Jj color Amplitude oT surface 6 7268 Figure 30 Zoom Out of 3D Scan Display Holding down the SHIFT key of the computer keyboard pressing and holding the left mouse button and moving the mouse allows for panning of the display see Figure 318 Page 27 of 39 Figure 31 Panning of 3D Scan Display The Cursor button turns on a cursor see Figure 329 which may be moved about the graph using the left mouse button to find amplitude at data point positions Amplitude fT Figure 32 Cursor On in 3D Scan Display Page 28 of 39 The Lighting feature see Figure 33 allows a virtual light to be powered and moved in latitude and longitude for better perception of the 3D surface Jj color d p E Figure 33 Lighting Effects in 3
26. eration Reducing external noise contributions can be very difficult In gradiometers especially in a laboratory environment significant noise can be introduced if the dewar is positioned near a metal fixture Section 4 3 discusses ways to reduce the influence of environmental noise sources 2 3 2 Test configuration SQUID Controller used IMC 303 S N 1098 Flux locked Loop used iFL 301 H S N 2071 SQUID sensor used HTG 10N S N G40810 System Channel 1 Test Setup Gain x100 Slew Normal Heater Test Heat Time 20 sec Cool Time gt 20 min Autotune Triangle Amplitude 2 4 V peak to peak Tune Parameters in mu metal shield unshielded 9 22 04 Bias 28 30 Bias 28 30 Mod 33 25 Skew 52 18 Note that tune parameters can vary and can be dependant on environmental noise Gain X100 X100 TE Slew Normal Slow 681 Balance gt 400 1 with respect to 60 Hz measured in the dBZ dy orientation 2 3 2 Unshielded Operation For planar gradiometers testing is also done in an unshielded environment Completely unshielded operation was achieved c f Figure 39 Chame Loop Locked Yes Page 6 of 39 7 of 39 2 3 3 Dewar Parameters The dewar construction Figure 5 is outer case is fiberglass with vacuum space superinsulated nitrogen reservoir and neck Volume 1 19 Liters Boil off no probe Dewar Tail Gap warm 4 1 mm cold 5 2 mm
27. ewar is equipped with a vacuum space evacuation valve mounted on the dewar top Before opening this valve a leak tight connection should be made to it and the pumping line to the valve should be evacuated using a leak detector or a pumping station equipped with a diffusion pump and cold trap or other pumping system with equivalent capability The cold trap is necessary to prevent back streaming of pump oil into the vacuum space after it has reached a low static pressure Page 36 of 39 OPEN THE VALVE VERY SLOWLY AND OBSERVE THE PRESSURE IN THE DEWAR DO NOT BEGIN PUMPING UNTIL YOU OBSERVE THE PRESSURE If you observe a high pressure more than a few torr you should pump the vacuum space very slowly by opening the valve as little as possible A satisfactory vacuum is about 100 200 millitorr when the whole dewar is at room temperature Depending on the pressure it may take up to 24 hours to obtain a satisfactory pressure WARNING DO NOT LEAVE THE DEWAR PUMPING UNATTENDED Since most of the time required is for outgassing of the surfaces in the dewar it is better to pump the dewar for 15 minutes every few hours There is little advantage to leave the pump connected continuously If your leak detector indicates any helium gas it may be advantageous to flush the vacuum space once with nitrogen gas Slowly fill the vacuum space with 10 torr of nitrogen gas this should not be done at a rate faster than 1 torr per
28. gen diffusion that occurs during normal operation through the warm upper portion of the neck tube Large quantities of air water and other gasses are also outgassed from the warm interior surfaces of the dewar vacuum space However there is a getter in the vacuum space which absorbs large amounts of gas when the dewar is cold Eventually the vacuum space of the dewar will need to be re evacuated This will become obvious in one of two ways e The nitrogen evaporation rate will increase during normal operation If the evaporation rate has increased by more than 30 you should consider pumping the vacuum space e You will be unable to transfer liquid nitrogen All of the nitrogen transferred into the dewar will immediately evaporate If the vacuum is extremely poor the outside of the dewar may get cold and even condense water especially along the tail If you suspect a poor vacuum use the following procedure to check and pump on the vacuum WARNING EXTREME caution must be used when examining the vacuum There are many fine layers of superinsulation in the vacuum space Rapid changes in pressure may cause rupturing of the superinsulation Therefore NEVER abruptly open the dewar vacuum space to atmospheric pressure the dewar vacuum should be slowly vented over a period of about 15 minutes The nitrogen reservoir must always be at room temperature when gas is admitted to the vacuum space or when it is being pumped The d
29. han one the measured values from each scan are averaged for each position measured The Clear button removes existing data which is being displayed Page 23 of 39 Figure 23 Scan Parameter Input of Main Window The File tab see Figure 24 controls the handling of acquired data The yellow Save Data button allows acquired data to be saved The Save Image button allows the current 3D scan display to be saved as a jpeg image The Load Sample button allows previously acquired data to be displayed on the 3D scan display for analysis The Load Reference button allows previously acquired data to be loaded as reference data for sample comparison and noise reduction purposes The Delete button allows for previously acquired data to be selected and removed from the computer Figure 24 File Parameter Input of Main Window 5 4 3 Time Display During a measurement the Time Display see Figure 25 gives a real time 1D picture of the Amplitude and Phase relative to the magnet output of the data being acquired The controls below the graphs allow for pan and zoom functions within the display Page 24 of 39 Right clicking mouse while pointing the cursor over the graph opens more graph controls 0 00E 0 nes M eoo ea oon IO Amplitude 5 00 9 1 00 0 Samples Figure 25 Time Display in Main Window 5 4 4 Status Display The Status Display see Figure 263 gives information regarding the current st
30. horizontal orientations the bottom of the sensor is recessed 1 mm above the bottom of the probe These distances must be added to tail gap to determine the sensor to sample distance Normallly the coil to room temperature distance is 10 mm when the dewar is cold The SQUID sensor was initially tested in a HTS superconducting shield to eliminate all external environmental noise contributions Testing was done using Tristan iMAG 300 SQUID electronics The flux transfer function and noise fT cmVHz was determined The test results of the supplied SQUID sensor is shown in Figure 3 as a function of frequency The white noise guaranteed lt 70 fT cmNHz was measured at 100 Hz and is listed along with sensitivity at 1 Hz not a guaranteed value but shown for informational purposes Faley M I Poppe U Urban K Paulson D N Starr T and Fagaly R L HTS dc SQUID with a gradiometric flux transformer Proceedings of the 4th European Conference on Applied Superconductivity EUCAS 99 Barcelona Published in Inst Phys Conf Ser No 167 p 509 512 2000 Page 4 of 39 540810 6 cable length ni cmtb Bias 42 94 Mod 6 6 peaks i 37 00 2 4 V ee 040810 n shik EE Unshielded 1 1 E Ee me EIU P ill TUE iil L
31. ity application for a SQUID by Levy and Greenfield Review of Scientific Instruments volume 50 May 1979 pp 655 658 describe how to build a suitable current source Even if the current source is quiet rf pick up on the leads connected to the current source can introduce substantial rf interference If you suspect that rf interference from the current source or the leads connected to it is a problem you should observe the periodic transfer function using the Analog Output on the iMC 303 Controller rear panel This is described in Section 3 9 6 of the SQUID System manual First tune channel by pressing the TUNE Key Then switch to the MANUAL TUNE display and observe the sinusoidal transfer function via the Analog Output BNC The transfer function should look like a clean steady approximately sinusoidal signal with the current source disconnected from the probe If it is severely degraded when the current Page 35 of 39 source is connected to the probe you can be sure that it is causing a problem You will need to replace the current source or improve the shielding of the leads Alternatively you can install additional rf filtering in the output lines from the current source 7 MAINTENANCE 7 1 DEWAR VACUUM Prior to cooling down especially if the dewar has been at room temperature for a long period of time he dewar vacuum should be checked to verify that the vacuum space is evacuated There is a small amount of nitro
32. lug pressure relief passages and foul relief valves Plugged passages are hazardous because of the continual need to vent the nitrogen Page 14 of 39 gas which evolves as the liquid continuously evaporates Therefore always store and handle liquid nitrogen under positive pressure and in closed systems to prevent the infiltration and solidification of air or other gases Do not permit condensed air on transfer tubes to run down into the container opening 4 3 5 KEEP EXTERIOR SURFACES CLEAN TO PREVENT COMBUSTION Atmospheric air will condense on exposed nitrogen cooled piping Nitrogen having a lower boiling point than oxygen will evaporate first from condensed air leaving an oxygen enriched liquid that may drip or flow to nearby surfaces Areas and surfaces upon which oxygen enriched liquid can form or come in contact with must be cleaned to oxygen clean standards to prevent possible ignition of grease oil or other combustible substances Leak testing solutions should be selected carefully to avoid mixtures that can leave a residue that is combustible When combustible type foam insulations are used they should be carefully applied to reduce the possibility of exposure to oxygen enriched liquid which could upon impact cause explosive burning of the foam 4 3 4 PRESSURE RELIEF DEVICES MUST BE ADEQUATELY SIZED Even minor deterioration of the vacuum in the nitrogen container can result in significant evaporation Pressure relief devices fo
33. magnetic field of the earth that can be 10 orders of magnitude greater than its sensitivity The magnetic field at the surface of the earth is generated by a number of sources There exists a background field of 50 uT with a daily variation of 0 1 uT In addition there is a contribution below 1 Hz from the interaction of the solar wind with the magnetosphere The remaining contributions to external magnetic fields Page 34 of 39 are primarily man made These can be caused by structural steel and other localized magnetic materials such as furniture and instruments that distort the earth s field and result in field gradients moving vehicles that generate transient fields electric motors elevators radio television and microwave transmitters and the ever present powerline electromagnetic field and its harmonics It is highly advisable to perform initial tests in a magnetically shielded environment If you do not have a shielded room measurements made after midnight or on the weekend can be compared to measurements during the day to see if there are environmental effects In areas where rfi is extreme it is advisable operate the system in an rf screened eddy current room If this is not possible wrapping the dewar in household aluminum foil may improve the situation This acts as an eddy current shield While it may reduce the system s bandwidth depending on the amount of aluminum foil used and perhaps increase the system s white nois
34. minute It should then be re evacuated as described above This procedure may be repeated several times until the helium level is low WARNING THE PRESSURE IN THE VACUUM SPACE MUST NEVER BE ALLOWED TO CHANGE QUICKLY RAPID PRESSURE CHANGES WILL CAUSE PERMANENT DAMAGE TO THE THERMAL SHIELD AND SUPERINSULATION If the dewar does not perform well after pumping the vacuum or if it requires pumping at intervals more frequent than once a year there may be a leak in the dewar If you suspect this problem contact your Tristan representative for assistance 7 2 HIGH TEMPERATURE SQUID SENSOR ADVISORY In order to insure optimum performance for your Tristan High Temperature SQUID system the following handling precautions should be followed Carefully adhering to these procedures will allow your instrument to function accurately for the duration of the warranty period and beyond Please feel free to contact Tristan with any questions 7 2 1 Handling for Shipping and or Storing at Room Temperature SQUIDs are electro static discharge ESD sensitive devices Always store them in appropriate ESD safe packaging Page 37 of 39 Use appropriate static sensitive handling equipment such as ESD mats and wrist straps when handling and connecting High Temperature SQUIDs Connect the shunting plug at the top connector when the SQUID 15 not in use for extended periods and always for shipment See Figure 41 Shunting plug side view Shu
35. nting plug SQUID with SQUID without end view shunting plug installed shunting plug installed Figure 41 Shunting Plugs Be sure to install shunting plugs on the connector of the SQUID when it is not in use for extended periods or during shipping Store the SQUID sensor in a moisture free environment by using desiccant in conjunction with a closed container This ts especially important in humid or damp environments Typically desiccant Silica Gel appears blue when active and red or pink when saturated with moisture See Figure 42 SNP sme mtr DE p Ee T m Mas ee is aM fsa ges t vd ey TA Parr t gt T s T IT x E o gt 5 lt a gt d Ai als 4 3 tart Jus E d Ann m val NT e n LR S 243 L2 e IG OG GRAM dene dt AN PES i EU rr Lu ah Figure 42 Silica Gel Indicator Colors Page 38 of 39 color indicates that the desiccant is still active A Red color indicates that the desiccant should be replaced When warming the SQUID sensor immediately place the SQUID sensor in a plastic bag when it is removed from the cryogen to minimize the condensation of water vapor on the cold surfaces After the
36. ol Down and Usage Do not touch the pins or connector of the SQUID Observe ESD precautions when connecting the SQUID s cables Do not measure SQUID cable resistances when cold Initial cool down of the SQUID is with the Tristan iFL 301 H flux locked loop electronics connected to the LEMO connectors at the top of the cryostat However do not yet connect the CC 6 composite cable s to the iFL 303 H Flux Lock Loop s Connect the CC 6 composite cable s to the Tristan model iMC 303 SQUID Control Electronics first Turn on the Tristan electronics with the SQUID not connected Go to SETUP MANUAL TUNING ENTER and then reduce Bias Mod and Skew to 095 Allow the SQUID electronics to stabilize for 10 minutes Connect the CC 6 composite cable s at the Flux Lock Loop first then connect 10 pin LEMO connector and then connect the 5 pin LEMO connector last If the SQUID is in a vacuum verify that the correct heater current limits are in place This is not normally applicable to the 703G system but is relevant if you are performing other tests Run the TUNE Utility Heat for about 3 seconds then pause for 2 minutes If the SQUID does not go normal as seen by observing the triangles as described in the User s Manual for iMAG HTS Multi Channel dc SQUID System you may increase the heat time in small increments until the SQUID goes normal If the heat time becomes excessively long contact Tristan or your local distributor for advice
37. on 4 Fill Color EN Surface Levels 20 10 J i e Sam vs Ref Figure 37 Sample vs Reference in 3D Scan Display To quickly view the graph from directly above the X Y plane click on the Face button see Figure 385 max 18 106 8 Zmn 6 726 86 zZ delta 1456 7 Page 31 of 39 z Grad jJ Color Lighting Lat jm _ Lon Fill Color Surface Levels 1 Jj Sample Zmax amp 10E 8 Zmin 6 72E 8 2 delta 1 48 7 Figure 38 Face X Y Plane in 3D Scan Display 5 5 Software Help A brief description of software features may be accessed at any time by pressing CTRL H and moving the mouse cursor over the main window To close the help either press CTRL H again or close the help dialog window 5 6 Sample scan It is recommended that the user begin with a simple object and to familiarize him herself with the capabilities of the SMM 701G This will allow the user to vary the scan parameters and compare their effects on a known output Page 32 of 39 Figure 39 dB dx scan of magnetic dipole Figure 39 shows a scan of a small magnetic dipole with the SQUID gradiometer in the horizontal dBz dx orientation tuning parameters given in section 0 The sample was made by cutting off a small 1 mm section of a paperclip Another sample could be a straight wire with a current flowing through it Figure 40 Section 6 1 discusses the difficulties associated with current s
38. open Page 11 of 39 CAUTION O rings located on the probe will not be flexible if cold and may easily be cracked Spare o rings are provided CAUTION To avoid contamination of the vacuum space do not freeze the pump out valve on the top of the probe or the gasket on the top of the probe during transfer 4 NORMAL OPERATION 4 1 REFILLING THE DEWAR WITH LIQUID NITROGEN After the initial nitrogen transfer subsequent transfers will be required on a regular basis The boil off time recorded in Table 1 for the dewar will be reduced when a probe is installed and operating The dewar is designed to operate in the vertical position and boil off will increase when the dewar is tilted from vertical The boil off of the dewar with probe should be measured this will determine the minimum time between refills of the dewar The dewar should be refilled periodically and should not be allowed to warm unintentionally via boil off Figure 12 Adding Liquid Nitrogen to a Cold Dewar Page 12 of 39 refill a cold dewar remove the fill tube plug and install the provided funnel into the fill tube Slowly pour LN into the funnel until LN2 vents from the vent port Wait a moment and then add more LN until it again vents from the vent port Repeat this sequence until adding liquid causes immediate venting The dewar is now filled Remove the funnel and replace it with the fill tube plug Leave the vent port open 4 1 1 HTS Sensor Co
39. ources Figure 40 Magnetic field gradient dB dx generated by a 1 mA current wire oriented in the y direction 5 7 File Format 5 7 1 Data file start description scan of paperclip 25x25 steps 1 0mm and 2 30 end description start miscvar gt File Format Version 1 0 Scan Start Time Tue 21 Sep 2004 at 14 38 20 7 h Scan Stop Time Tue 21 Sep 2004 at 15 14 25 7 h Total Scans 1 00 Total Samples 400 Total Channels 2 Center XYZ 0 00 0 00 30 00 Page 33 of 39 Step XYZ n XYZ 4 00 4 00 1 00 20 20 1 end miscvar gt start header X position mm deg end header start databody gt Y position mm Z position mm 40 000 40 000 30 000 3 20792E 7 0 00000E 0 8 10658E 2 0 00000E 0 36 000 40 000 30 000 3 06972E 7 0 00000 0 8 07005E 2 0 00000E 0 32 000 40 000 30 000 3 04671E 7 0 00000 0 8 00491E 2 0 00000E 0 32 000 36 000 30 000 3 12402E 7 0 00000E 0 8 44737E 2 0 00000E 0 36 000 36 000 30 000 3 13715E 7 0 00000E 0 8 41468E 2 0 00000E 0 40 000 36 000 30 000 3 11499E 7 0 00000E 0 8 35829E 2 0 00000E 0 Ch1 Amplitude fT Phase deg Ch2 Amplitude fT Ch2 Phase end databody gt 5 7 2 Acqusition parameters file current ini Motion MotorEnabled TRUE MotorConv steps mm 3200 000000 3200 000000 1250 000000 MotorSet steps rev 3200 3200 3200 MotorVelocity 50 000000 MotorAccel 20 000000 ResetPos mm 9 5125 8 2812 75 5000 InitPos
40. ower Cord Dell CD ROMs and Manuals National Instruments CD ROMs and Manuals RS 232 Cable Parker Motion Control Manuals Model SMM 701G Manual The country of origin for all components is the United States with the exception of the HTG 10N SQUID sensor whose country of origin is Germany is a registered Trademark of Tristan Technologies Inc Rights Reserved Page 3 of 39 2 3 MEASURED PARAMETERS AND FACTORY TEST DATA The following parameters were measured at Tristan prior to shipment Dimensions and weights are approximate and are given for reference only Performance data is the result of testing done at Tristan Boil off tests values were taken after thermal equilibrium was established Under ideal conditions you should expect to achieve similar performance in your laboratory but some differences are to be expected 2 3 1 SQUID sensor The HTG 10N is a flip chip design with a detection coil mounted directly above that of the Josephson loop Figure 2 shows the shape of the detection coil The center to center distance is 10 mm The effective baseline may be slightly larger because of the width of the patterned lines The black regions indicate where the YBCO superconductor is placed 15 mm 13 mm Y 10 mm i X Figure 2 Mask of HTG 10N planar gradiometer input coil shown at 2x actual size The plane of the SQUID chip is located 4 mm from the bottom of the HTG 10N SQUID sensor In the dBz dx or dBz dy
41. r liquid nitrogen equipment must therefore be of adequate capacity to release nitrogen vapor resulting from such heat inputs and thus prevent hazard due to excessive pressure This system has been designed to safely vent the evolving nitrogen gas in the event of any reasonable failure mode WARNING DO NOT MAKE ANY MODIFICATIONS TO THIS SYSTEM WHICH MIGHT AFFECT ITS ABILITY TO VENT NITROGEN GAS IN THE EVENT OF AN EMERGENCY SUCH AS LOSS OF VACUUM IN THE DEWAR VACUUM SPACE 4 3 5 KEEP EQUIPMENT AREA WELL VENTILATED Although nitrogen is nontoxic it can cause asphyxiation in a confined area without adequate ventilation Any atmosphere which does not contain enough oxygen for breathing can cause dizziness unconsciousness or even death Nitrogen being colorless odorless and tasteless cannot be detected by the human senses and will be inhaled normally as if it were air Without adequate ventilation the expanding nitrogen can displace air and result in an atmosphere that is not life supporting The issuing nitrogen gas 15 invisible Liquid containers should be stored in large well ventilated areas If a person becomes groggy or loses consciousness when working around nitrogen get them to a well ventilated area immediately If breathing has stopped apply artificial respiration If a person loses consciousness summon a physician immediately Page 15 of 39 5 DATA ACQUISITION AND SCANNING SOFTWARE 5 1 Block Diagram Figure 13 sho
42. recommend that you save the shipping crates for possible future use in case the system has been damaged and needs to be repaired Flux Locked Loop iMC 303 SQUID Controller Nitrogen Dew ar t Software data acquisition analysis motion control HTS SQUID Sampl Non Magnetic Stand off X Y Z Scanning Table Figure 1 Model SMM 701G components Page 2 of 39 2 2 1 List of system components Model iMC 303 iMAG SQUID Control Electronics Model iFL 301 H iMAG Flux Locked Loops Model NLD 530 T liquid nitrogen dewar LN filling funnel Model NL 51G 1 channel SQUID probe Model HTG 10N planar SQUID gradiometer dBz dx Model CC 6 six meter composite cables HTS iMAG User s Manual and Applications Disk X Y Z Motion System BNC 2090 Junction Box SH 68 to SH 68 Digital Cable MID 7604 Stepper Motor Drive Motion Control Cable 2 6 Motion Table 8 Motion Table QTY 2 57 Stepper Motor Attached to Motion Tables Dell 19 Monitor M992 Dell CD ROMs and Manual Power Cords Dell Precision 360 Workstation Windows XP Operating System National Instruments 4 Axis Stepper Controller National Instruments Multifunction Digital I O Dell Keyboard Dell Mouse P
43. ry to set this non zero to allow for mechanical and SQUID settling Input ranges controls the maximum range of the acquisition hardware for each channel The channel is selected by the numeric control and range by the menu The range is plus or minus the indicated value This controls the pre amplifier gain of the acquisition hardware Sample Rate is fixed at 100 kHz Page 21 of 39 Figure 20 Acquire Parameter Input of Main Window The Excitation tab see Figure 21 controls the output of the AC magnet Frequency sets the cycles per second of the signal and Amplitude sets the magnetic flux density at the bottom of the dewar tail When frequency is set to zero and amplitude is set to a non zero value the magnet output is DC When Amplitude is set to zero there is no magnet output This tab has been removed for the Wright Patterson installation as there is no AC magnet currently included with the system Figure 21 Excitation Parameter Input of Main Window The Move tab see Figure 229 controls both stage position and stage position limits To move an axis change the value for that axis for Position To redefine stage position limits change the value of the position to the desired limit and then click on the corresponding numerical value for either the or Limit Page 22 of 39 WARNING MOVING STAGES INTO OBSTRUCTIONS COULD CAUSE DAMAGE TO THE OBSTRUCTIONS AND OR TO THE SMM 701G SYSTEM WHICH ARE NOT COVERED BY THE TRISTAN TECHNOL
44. stances including installation and connection detail After obtaining authorization from the Tristan Page 9 of 39 representative return the unit for repair along with tag to it identifying yourself as the owner Please enclose a letter describing the problem in as much detail as possible 3 1 1 REPACKING FOR RETURN SHIPMENT If itis necessary to return the system you should repack the unit in its original container if available For this reason it is advisable to save the original crate sent by Tristan however if this is not possible use the following instructions for repacking 1 Wrap the unit in either bubble wrap or foam rubber 2 Cover the bottom of a sturdy container with at least 3 inches of Styrofoam pellets or shredded paper 3 Set the unit down onto the packing material and fill the rest of the container with Styrofoam or shredded paper The unit must be completely protected by at least 3 inches of packing material on all sides 3 1 2 RETURN FROM CUSTOMERS OUTSIDE THE USA To avoid delays in Customs clearance of equipment being returned contact the Tristan representative in your area or the Tristan factory in San Diego California for complete shipping information and necessary customs requirements Failure to do so can result in significant delays 3 2 NORMAL INSTALLATION The SMM 701G scanning stage including liquid nitrogen and SQUID probe requires an area of 75 cm x 150 cm 3 x 6 The computer SQU
45. ws the main components of the data acquisition system The software is described in section 5 2 1 ENC 2090 a IMc 303 rock Tua Te Ee Figure 13 Data Acquistion Block Diagram 5 2 Software Start To begin using the Tristan Technologies SMM 701G Magnetic Field Imaging System software double click on the MagScan exe shortcut on the desktop or from its location in the C MagScan folder After the software opens the Initialization File Window see Figure 1411 will open and prompt the user for a selection The Default ini selection will set all software parameters to the factory settings while the Current ini selection will set Page 16 of 39 software parameters to the previous parameter settings from last time software was run IE Initialization File Default ini Current ini Figure 14 Initialization File Window After the initialization file is loaded the software will prompt for Motor Position Initialization see Figure 1512 Be sure that the sample stage is free from obstructions before clicking OK button Figure 15 Motor Position Initialization Prompt Page 17 of 39 WARNING CLICKING THE OK BUTTON IN THE MOTOR POSITION INITIALIZATION PROMPT WILL ALLOW THE SAMPLE STAGE ASSEMBLIES TO MOVE IN ALL THREE RECTANGULAR COORDINATE AXIS SIMULTANEOUSLY OBSTRUCTIONS TO THIS MOTION COULD CAUSE DAMAGE TO THE OBSTRUCTIONS AND OR TO THE SMM 701G SYSTE
46. y auto scrolls to the bottom of the log to display the most recent commands To view previous commands from the current log uncheck the box and use the scroll bar at the right of the display To view logs of previous runs access the txt format files in the directory 30 Sep 2003 at 16 45 43 3 h System Initialization mode has been completed Proceeding to System Operation mode Figure 18 User Log Section of Main Window Page 20 of 39 5 4 2 Parameter Input The Parameter Input section of the main window provides the controls for setting up initiating and saving data The section is made up of six tabs each of which controls a different aspect of the measurement process The SQUID tab see Figure 196 has controls that perform functions available from the front panel of iMAG SQUID controller These functions are described in the iMAG SQUID Controller Manual These controls are disabled during a scan but may be used between scans or when a scan is paused SQUID Acquire Excitation Move Scan high pass filter Dc ll Low Pass Filter off offset 0 normal Figure 19 SQUID Parameter Input of Main Window The Acquire tab see Figure 207 has controls for the acquisition of data Measure time sets the duration of the acquisition used for the measurement of each point in a scan Settle time sets the duration of acquisition after a move that is discarded It may be necessa
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