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Using in situ neutron and gamma-ray spectroscopy to

1. utes PAGE 1 Material Configurations for Each PING Experiment 28 2 Y ray lines to analyze for inelastic Y ray spectra time window optimization 44 3 HPGe gamma ray line intensities IL and uncertainties o during different time windows for a 6 33 hr PING acquisition on the bare Columbia River basalt monument For the 1779 and 6129 keV activation peaks the half lives are 2 3 min and 7 1 s respectively Note the Activation column includes data from all times that the neutron pulse was off Neutron thermalization begins even before the fast neutron pulse turns off at 100 us and it reaches a peak at approximately 100 us and then slowly decays therefore the H n y 2223 keV gamma ray line appears in both the inelastic scattering and thermal neutron capture windows due to the time windows selected Tor tlie Se Proces SES xui ones wales evened Eder 48 4 Fast neutron induced count rate and uncertainty for the 6129 keV l O n n y gamma ray peak for ten time slices during the PNG poulse 51 5 Energy Calibrations for Summed Time Sliced Granite Basalt and Asteroid Simulant Configurations Data using HPGe Bare and Boron Wrapped Detector 67 6 Granite Basalt CI1 chondrite meteorite element concentrations 78 7 Gamma ray line intensities and uncertainties for the PING granite monument data with the HPGe detector wrapped in a boronated rubb
2. PAGE Asteroid taxonomie CldsSt16 UOTIS EE 3 2 An illustration of the different types of space weathering processes that alter the 10 11 12 surface geochemistry of ASLELOICS EE 4 Illustration of PING mounted on a rover showing how it can be used to determine the bulk elemental composition over a 1 m surface area and down to 50 cm below the Surface EE E E 12 PING takes advantage of four different gamma ray producing processes inelastic scattering neutron capture neutron activation and natural radioactivity to determine the elemental abundance of the planetary material csseesseeceeceeeeeeeeeeeeeeees 14 Aerial view of GGAO This schematic of the outdoor gamma ray and neutron instrumentation testing facility shows the operations control building as well as the 47 m diameter safety perimeter surrounding the two existing 1 8 m x 1 8m x 0 9 m Pranite and basalt monure nts sace ute b dti cetus aa udt a das peto tet adu ps 21 A drawing of the soil profile performed by Gunther Kletetschka and Julia Bodnarik on their shoveled out 0 9 m x 0 9 m x 0 6 m meter pit in the middle of the field at GGAO With 2 Idm tall erass on EI EE 22 Image of the test facility with the operations building left the basalt monument covered with the homogenous C type asteroid layering simulant right and granite rion ment EAL SELON oc oec me dran eg 23 Image of PING components on the C type asteroid simula
3. 12098 0235 nA Hr Exposure 2565340 Hr Interlock Tee 00 00 00 e Setting 00 00 00 TI P 385 E v SZ SCIENTIFIC Figure 9 PNG Main GUI Display b The system should be in a fault state since the HVPS disable box red interlock button is pushed down Click on Fault Analysis on the Screen pull down menu tab to view the current system faults Li anus a HCH Fault Analysis 0x0002 0x0000 0x0000 0x0000 0x0000 0x0000 F Main DNC Board Faults F RED User Interlock F gt End Fault Analysis er Int tr i On Stande 10000 Hz E Mounal 150 DF Meutrons Mode State Totakeas FAULTED 1z02 17 03 watt 2569539 He UU U U P 385 zm EM Pulses 1771537 SCIENTIFIC Figure 10 Fault Analysis Window PNG Operations Manual 02 02 201 1 Page 8 of 11 140 A window will pop up showing system faults The example in Figure 10 shows a fault indicating that the user interlock is in the open state the HVPS disable box red button is pressed down First insure that all personnel are clear from PNG and outside of the 250 foot radius radiation keep out zone Then twist and release the red button and click on the Clear Faults button on the GUI interface This will bring the PNG system into the IDLE state shown in the State display box on the Main GUI interface 2 Setthe Beam Current and High Voltage a Enter in your beam current A and high voltage kV settings for the PNG by typing their values into the boxes
4. 182 9 cm gt Granite Monument Asteroid Simulant HPGe Crystal HPGe Aliis PNG Source amp 182 9 cm 182 9 cm amp 182 9 cm gt PNG Source Figure 43 Aerial view of MCNPX geometry and space of HPGe crystal and PNG source point on top of the granite basalt and asteroid layering simulant configurations The second input script used the F2 tally surface tally of the HPGe detector crystal surface to define the input gamma ray energies and intensities for the cylindrical gamma ray beam source that is aimed axially at the HPGe detector crystal to determine the gamma ray efficiency of the detector for different gamma ray line energies by providing a F8 pulse height tally units energy volume normalized to one input particle 74 e g MeV cm photon for the gamma rays detected in the volume of the HPGe detector crystal The first input scripts were run for 50 hrs each on 128 processors on the NASA Center for Climate Simulation NCCS Discover cluster Westmere for a total number of particles of 2x10 neutrons per script using MCNPX version 2 6F March 2008 and the associated data and cross section libraries The second input scripts were run for 15 minutes each on processor on an HP Pavillion Elite HPE with an AMD Phenom II X6 1060T 3 20 GHz processor 16 0 GB RAM and a 64 bit operating system running Windows 7 Ultima
5. Table 21 ActLabs Concord Grey Granite Elemental Assay Report A09 1100 Final Report Activation Laboratories Report Date 14 04 2009 Concord Grey Granite Elemental Assay Activation Laboratories Ltd Ancaster Ontario Canada Analyte Symbol gd Mess oul Tois ol Mass sl sau sel Azos rezosm wall weg UntSymbo m g a vw ai v a al veo vw o ose Detection Limit os ooj ooj wel f oof oof oof oof aal aal oe Analysis method panaa Pew m e mal wl i Analyzer Fusce Fusce Fusce Fus ice rusce Easrsoe LJ iof oof aal wl el awa ooi ae tao oa aal os wEsTsibE 109 229 aa oo aal mei aal am 7200 al 1 73 ose oe Eerspecemwi LL j f 743 2 155 oos os wesrsbe cena LL P stats Aal oos oz paver eramo LL II LI IL asi ol ad aal o p Analyte Sub cao wel wei mol ol iof sel el el va co w pom pem ppm ol oe Detection Limit oof oof ooj aan ol oof tft A d 20 Ja Easrsoe oe sof sz oza wel osf al s wu al d a wesrsioe os sa sa ol ol wl soo a oA o so af lt a PAVER os sof am o2 aal awe aal af of wall d 20 EAST SIDE CERAMIC 09 al sa o2u ol o74 1o09 ai wd 10 al Ja Paver ceramic el 294 vi ve ol o7e am d d e al JI a SSES Analyte symbol cu al el ol wl ml sd v z nof vof wx Easrsoe Lo ml al d 2 el eef sl ol aal af al a Westsie lt o 7o 24 15 9 ei
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8. Tables Charts SmartArt Formulas Data Review a ZB L Edit Font Number Format Cells Themes Calibri Body 12 E Wrap Text General x Eer E g g Tei Lab EE ssi HM E EL n0 mssss v Q 0 00 iti x Paste BjIjU EI A gt Sio 3 0 Conditiona Styles Insert Delete Format Themes Aa g C1 2 fx PCM WP u o un uu wo Ka T D E H I J Pest L M N o 909 5991 Fixed 13495 525 Fixed 0 8170512 Fixed 1 25 Fixed 1 36048 2 4796 Gauss Tail 2089 Fixed 1032 84878 Fixed 2 470864 Fixed 1 25 Fixed 4 114259 9 9974 Gauss Tail 2298 Fixed 1298 37902 Fixed 2 569585 Fixed 1 25 Fixed 4 27864 10 606 Gauss Tail 2507 Fixed 1388 98895 Fixed 2 668306 Fixed 1 25 Fixed 4 443022 11 232 Gauss Tail MEN mg Sheetl ka B Normal View Ready sum 7803 5991 vw Figure 30 Example of a MS Excel file with the copied report 61 3 The energy and corresponding centroid channel are entered into a new Igor table an XY graph is created of channel vs energy and a straight line y mx b is fit to the points where m gain and b offset Under Windows select New Table New Graph New Layout New b Close SEW Send To Back ABE Bring To Front dE Show D Hide E Control D Help Browser Help Windows Command Window EI Procedure Windows Data Browser Graphs Tables Layouts Other Windows Recent Windows rT
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10. A mineralogical chemical systhesis Meteoritics and Planetary Science 36 1661 1672 20 Feldman W C et al 2004 J Geophys Res 109 EO7S06 21 Boynton W V et al 2004 Space Sci Rev 110 37 22 Boynton W V et al 2002 Science 297 81 23 Prettyman T H et al 2003 IEEE Trans Nucl Sci N50 1190 24 Goldsten J O et al 2007 Space Sci Rev 131 339 25 Evans L G et al 2001 MAPS 36 1639 26 Mitrofanov I G et al 2010 Space Sci Rev 150 183 27 Mitrofanov I G et al 2008 Astrobiology 8 793 28 Akkurt et al 2005 Nucl Inst Meth B 241 232 29 Schweitzer J S 1993 Subsurface Nuclear Measurements for Geochemical Analysis 1993 Chap 23 in Remote Geochemical Analysis Elemental and Mineralogical Composition Topics in Remote Sensing 4 Carle M Pieters and Peter A J Englert Eds Cambridge University Press 30 McCoy T J T H Burbine L A McFadden R D Starr M J Gaffey L R Nittler and others 2001 The Composition of 433 Eros a Mineralogical Chemical Synthesis Meteoritics and Planetary Science 36 1661 101 31 Grau J A et al IRRMA 92 Raleigh NC 8 11 Sept 1992 1993 Int J Rad Appl Instr Part E 7 173 32 Parsons A et al 2011 Nucl Instr and Meth A 652 674 33 Schweitzer J S 1993 Subsurface Nuclear Measurements for Geochemical Analysis 1993 Chap 23
11. Graph Macros Table Macros Layout Macros Other Macros TYT YFF Y Figure 31 Image of Windows panel in Igor Under the first column enter the relevant energies This will be your Y AXIS eoo Tablel wave O RA LI v L i 1779 1 5107 z 5518 A 6129 4 Figure 32 Image of the gamma ray energy list in the new table 62 e After the energy values are entered right click on wave0 and Rename the wave to Energy Rename Objects Waves from Target current Name Type New Name mot 000 00 o Wave Energy o E wave b Packages gt bb WinGlobals To Cmd Line ToClip Help Cancel Figure 33 Image of the Rename Objects window in Igor e Inthe second column paste the values copied from the excel file these will be your Channels rename the column appropriately eoo Tablei Energy waveO 909 599 Figure 34 Image of the gamma ray channel list in the new table 63 e After both columns are named create a new Graph by selecting New Graph under the Windows menu Under the Y Wave s column select Energy Under the X Wave column select Channel New Graph Y Wave s X Wave root MoreChoices root 44A o Al uy H A ele amp Channel From Target EN Energy amp Energy AD fi amp fit Channel EI fit Energy EN fit amp fit Channel E ES ix EI Gauss 1l EM Gauss
12. IV nan F Esc 5 208 V pm V H 37 r2 C 846 343 307677 100 233017 Cep I Esc Free v Free Faxed v Fee v 2 875107 1 89748 1 25 4286 31 64331 Esc Fxed vw Fed v Faxed v Fxed 3 893544 1 90902 1 25 3120 02 47658 Esc Fed Fixed Fixed v Faced 4 811 762 1 9148 1 25 2008 37 3080 06 Esc Faxed Fred Fxed gt Fxed fni opgnppbeoe A Asint Ice D pnt 373 X 911 76 Y 25724 dX e Jes BR LI LET e LE es n Nm d Wid aa 0 4 0 Pea Amp Load Epoch Params Load Peaks Parameters Save Parameters Report Fit Folder A wet xed ESTETIS EC T55 7 Troe fam 203 Troe z T704 0 Junction Fixed 71 25 ints 74 num free params 3 Figure 39 Fitting four peaks on top of a Ge sawtooth peak Note the better baseline fit aqua blue lines due to the exclusion of peaks lime green that are not currently being fit in the peak fit window purple lines No peak parameters file in use Baseline 6139 28 2 6389 2 51596 3 589 x 1 Peak 0 Gauss Tail area 3207 03261 2 79 Amplitude Free 2372 02437 66 2808 Centroid Free 1765 51923 0 0 68758 Width Free 2 3288541 0 0598263 gauss 3 8778 True FWIM 7 0677 Junction Fixed 100 Peak 1 Gauss Tail area 55171 0795 9 46 Amplitude Free 35981 0915 3405 31 Centroid Free 1781 35
13. Schematic of the cross section perpendicular to the cylindrical axis of the n type HPGe detector crystal 33 Radiation is measured by the detector according to the number of free charge carriers between the detector s two electrodes produced by ionizing radiation interacting with the crystal creating free electron hole pairs 62 The intensity of the detected radiation 1s proportional to the number of electron hole pairs The ionizing radiation creates a number of electrons that are transferred from the valence to the conduction bands and an equal number of holes are created in the valence band When a potential is applied across the detector s two electrodes the electrons and holes travel in opposite directions to the electrodes resulting in a pulse that is measured by an outer circuit described by the Schockley Ramo Theorem Since the energy to create an electron hole pare 1s known the measurement of the number of electron hole pairs is proportional to the intensity of the incident radiation on the detector Neutron Detectors A Cd wrapped He epithermal neutron detector aluminum cylinder length 15cm aluminum cylinder radiusz1 25cm Cd wrap _ thickness 0 02cm He gas pressure 0 035g cm 200atm and a bare He thermal neutron detector aluminum cylinder length 15cm aluminum cylinder radius 1 25cm He gas pressure 0 035g cm 200atm from the University of Tennessee were used to collect neutron data for the PING instrument ex
14. What techniques have been sed 6 What do we want to know about asteroids and how can we get this re eene RE 7 What do we not know about asteroids essen 7 What are the advantages of in situ vs orbital neutron gamma ray Ie Sure Phe E 8 What possible in situ measurement techniques can be used to obtain the C complex asteroid bulk oeeochemstrg essere 10 PRS TATE TIVE AS UE TNE a A E A A 10 EE 13 Gamma Tay BEE EES 15 Neutomdatr a HALE EE 16 Studying the subsurface elemental composition of asteroids using PING 17 Teste PING On OQ iii asit nti a quote o c5 a aatauess tiene Vien muansendadasentawenta 17 Testing PING on an asteroid simulant cc cecccccccccccceeeseeeeceeceeeeeaeeesseeeeees 18 IL EXPERIMENT DESCRIPTION errestan a e 20 Design of the Goddard Geophysical and Astronomical Observatory GGAO neutron gamma ray instrumentation test facility sese 20 Neutron gamma ray instrumentation test facility eeeeeeessessss 20 Design of physical rock configurations cc eeeeeescccccceceseeeeeeecceeeeeeaaaeeeeeeeees 23 Meter sizod Ee E Ee 24 Experimental Rock Conteuratons esses 27 PING experimental equipment set up on rock configurations 29 vi PING experimental equipment description 30 P ulsed neutron reese eet ee E vdoal quete E Eet 30 Acquisition electronics gamma ray and neutron detectors 32 EE ee EE eg 32 NEI
15. 00 We 25 0 Beam Cunent nS m Y On Standby 10000 Hz ow A Norme 150 Bee Nes Ree 31 SOFT RT BEAM EI E os Time 00 00 00 ELE 00 00 SCIENTIFIC Figure 12 Startup on the Main GUI Display PNG Operations Manual 02 02 201 1 Page 10 of 11 142 5 Standby the PNG a Toggle the Mode labeled software switch from the NORMAL position to the STANDBY position High Voltage kV 75 Getter Current A 2 42 50 100 150 AU 200 High Voltage 200 0 1600 1200 Gab 40 ao 8 d Neutrons 125 Pulser Internal E ye ELA Hz o o DES Newtons Mode 25 Ki 0 o 3 5 x State Totalizer Beam Control HV Control STANDBY EECEXJ 2565213 Hi rees P385 Setting 00 100 00 00 00 Pulses 62300 2 SCIENTIFIC Figure 13 Standby Mode Screenshot b You will want to use the Standby mode when a rapid re start is required since it allows you to stop neutron production for short periods of time The HV will remain at the value that you configured and the reservoir current will stay at the value necessary to maintain your configured beam current There will be an indication of a small about of beam current on the main GUI display inherent in the HVPS measurement circuit but this is not an indication of target current The bleed off current is 1 A for every 20kV of HV The system will maintain the standby state for up to 15 minutes and then go back to the idle
16. 1 5 Ci 55 5 GBq of tritium works by having ions accelerated to a target and 14 MeV neutrons are produced through the reaction D T gt n He The tube is pulsed electronically and consists of a source to generate positively charged ions Figure 11 is an illustration of a PNG that consists of one or more structures to accelerate the ions usually up to 80 kV a metal hydride target loaded Tritium Deuterium lon Tritium Deuterium Figure 11 A schematic of a PNG 31 with either deuterium tritium or a mixture of the two and a gas control reservoir also made of a metal hydride material Figure 12 is a photograph of a generator 61 J Figure 12 A picture of a Cockroft Walton neutron generator Acquisition Electronics Gamma Ray and Neutron Detectors During these experiments we acquired event by event time tagged channel energy and time information or time stamped list mode TLIST data using Lynx Digital Signal Analyzer DSA electronics connected to an n type Ortec GMX Series HPGe portable coaxial detector system University of Tennessee thermal bare He and epithermal Cd wrapped He detectors and a PNG positioned on top of various rock and layering configurations shown in Figure 4 The Lynx DSA reading out the HPGe and thermal and epithermal neutron detectors were connected directly to the PNG to synchronize the start of each data acquisition run with the start of a neutron pulse Gamma Ray Detector An
17. 1 a Gauss 2 A Gauss_2 EI Gauss_3 22 Gauss A ignore E Axis left Swap Trace X amp Y Axes Axis bottom Title Style none Display Energu vs Channel Dok To Cmd Line ToClip Help Cancel Figure 35 Image of the New Graph panel 4 A new energy scaled spectrum wave is created with the applied energy calibration e Under the Analysis menu select Curve Fitting Curve Fitting Quick Fit Fourier Transforms Convolve Correlate Differentiate Integrate Smooth Filter Resample Wave Stats Sort Histogram Statistics Compose Expression Interpolate Packages b Wave Arithmetic Panel Figure 36 Image of the Analysis menu 64 Set Function to line Y Data to Energy and X Data to Channel The resulting graph s are your original line and the curve that fits your data Curve Fitting Function and Data rulers Data Options Coefficients Output Options Function Y Data _ From Target Energy line X Data If you have only a Y wave select calculated Channel New Fit Function Edit Fit Function E Use Multiple Processors Show Equation Commands a bx No Error Dolt To Cmd Line ToClip Cancel 5000 4000 3000 2000 1000 1200 1400 1600 1800 2000 2200 2400 F
18. 1 log pdf 120330Gel TLTOOI 1 capture filtered pdf 120330Gel TLTOOI 1 DANA filtered pdf 120330Ge1TLTOO1 1 inelastic filtered pdf 120330Ge1TLTOO1 2 log pdf 120330Gel TLTOOI 2 capture filtered pdf 120330Gel TLTOOI 2 DANA filtered pdf 120330Ge1TLTOO1 2 inelastic filtered pdf 120406Gel TLTOOI 1 log pdf 120406Gel TLTOOI 1 capture filtered pdf 120406GelTLTOOI 1 DANA filtered pdf 120406GelTLTOOI 1 inelastic filtered pdf 113 120406GelTLTO0OI 2 log pdf 120406Gel TLTO0OI 2 capture filtered pdf 120406GelTLTO00I 2 DANA filtered pdf 120406GelTLTOO1 2 inelastic filtered pdf 120408GelTLTOOI log pdf 120408Gel TLTOOI capture filtered pdf 120408GelTLTOOI DANA filtered pdf 120408GelTLTOO1 inelastic filtered pdf 120410Gel TLTOOI log pdf 1204 10Gel TLTOOI capture filtered pdf 120410Gel TLTOOI DANA filtered pdf 1204 10Gel TL TOO inelastic filtered pdf 120411Gel TLTOOI log pdf 120411Gel TLTOOI capture filtered pdf 120411 Gel TLTOOI DANA filtered pdf 12041 1 Gel TLTOOI inelastic filtered pdf 120412Ge1TLTO001 1 log pdf 120412Gel TLTO002 log pdf The thermal and epithermal neutron data is listed in the following files 110823Hel TLTOOI log pdf 110823Hel TLTO002 log pdf 110824Hel TLTOOI log pdf 110824Hel TL T002 log pdf 110824Hel TLTO003 log pdf 110824Hel TLTO00OA log pdf 110824Hel TLTOOS log pdf 110824Hel TL T0O6 1 log pdf 110824Hel TLTOOO log pdf 110824Hel TLTO007 log pdf 110824Hel TLTOOS log pdf 110930Hel TLT0
19. 3 150 650us filtered pdf 120322GelTLTO002 DA 4NA 18 3 650 1 999 9us filtered pdf 120322Gel TLTOO2 inelastic filtered pdf The available data for the 2 3 configuration 1s as follows 120302GelTLTOOI log pdf 120302Gel TLTO0OI capture 16 150 650us filtered pdf 120302GelTLT001 DANA 16 650 1 999 9us filtered pdf 120302Gel TLTOOI inelastic filtered pdf 120305Gel TLTO00O3 log pdf 120305Gel TLT00O3 capture 17 3 150 650us filtered pdf 120305GelTLTO003 DANA 17 3 650 1 999 9us filtered pdf 120305Gel TLTOO3 inelastic filtered pdf 120305Gel TLTOOA log pdf 120305Gel TLTOOA capture 17 3 150 650us filtered pdf 120305Gel TLT004 DANA 17 3 650 1 999 9us filtered pdf 120305Ge1TLT004 inelastic filtered pdf 116 120306Gel TLTOOI 1 log pdf 120306Gel TLTOOI 1 capture 17 1 150 650us filtered pdf 120306Gel TLT001 1 DANA 17 1 650 1 999 9us filtered pdf 120306Gel TLTOOI 1 inelastic filtered pdf 120306Gel TLTOOI 2 log pdf 120306Gel TLTOOI 2 capture 17 1 150 650us filtered pdf 120306Gel TLT001 2 DANA 17 1 650 1 999 9us filtered pdf 120306Gel TLTOOI 2 1inelastic filtered pdf 120306Ge1TLT002 log pdf 120306Gel TLT002 capture 17 1 150 650us filtered pdf 120306GelTLT002 DANA 17 1 650 1 999 9us filtered pdf 120306Gel TLTOO2 1inelastic filtered pdf 120307Gel TLTOOI 1 log pdf 120307Gel TLTOOI 1 capture 17 4 150 650us filtered pdf 120307Gel TLT001 1 DANA 17 4 650 1 999 9us filtered pdf 120307Gel TLTOOI inelastic filtered pdf 120307Gel
20. HPGe detector on top of Columbia River basalt Figure 17 is a plot of four different gamma ray spectra for a 6 33 hr live time acquisition with the PING instrument using a HPGe detector on the basalt monument consisting of 1 a total gamma ray spectrum in black including all neutron nuclei gamma ray processes 2 an inelastic gamma ray spectrum in red created by only selecting gamma ray events during the PNG pulse for t 20 100 us 3 a neutron capture gamma ray spectrum in green created by only selecting gamma ray events after the PNG pulse for t 150 650 us and 4 a delayed activation and natural activity gamma ray spectrum in purple created by only selecting gamma ray events for t 650 999 us Note that as expected different gamma ray lines appear in these spectra Our technique thus allows us to isolate gamma ray events for specific interactions from a single element without accumulating excessive background when the peaks are not actually present 43 Even if a better energy resolution detector like HPGe is used gamma ray line identification can still be challenging due to multi element neutron nuclei interactions that produce gamma rays at the same energy but from different elements Table 2 lists examples of gamma ray line energies and their possible sources from neutron nuclei interactions with different elements demonstrating how multiple elements can contribute to the same line energy Note that the first entry in Table 2 con
21. LO AZOTOT Tv6 9 ST00000 0 uMou xun c0 3 9 c0 3 9 0 300 2 Tv6 9 c Tv6 9 S 100000 0 S T wdd n 8T8ZTT00 0 SC 3C S Te ae4soec c Vc 3v6cvE T SbTZ89T00 0 990 7 TvS0 0 uwouxun I0 307 s I0 30c S 0 300 9 990 ZE 9 990 ZE TvS0 0 Ty s IM S 9T S0 386662 T LC 3LE TC 3IS S8 vc 3v6cvE T 6 vc 87000 ZOTO ZT SvE O O uMou xun 0 3 E 0 3 V0 300 8 LOTO ZT 8 Z0TO ZT Sv O 0 Spe 9 91M 2 9 OI 3PZ9Tv EIN T 3 SETS t vc 3v6cvE T TTI Hp609 T68CO 8 c 800000000 0 uMwou xun 00 3Z8 Z 00 4ZS 2 S0 300 T68Z0 8EZ T68zZO 8Ez 800000000 0 8 qdd n c6 60 3TOZv7 T vpc 3v L VI 3p8 9 1 vtct3v6cvE T OT 36 6v7 T I8 0 CEC 620000000 0 uMouxun 00 30t Z 00 30t Z V0 300 T TSE0 ZET T T8E0 ZEZ 620000000 0 6c qdd cs uL 06 TT J69ZEE Z 9c 3 vT 394890 Z Vvc 3v6cvE T OT 4S9 97 S 8 086 80Z TT000000 0 umouxun c0 30 c0 30 S0 300 2 8 086 80c Z 8 086 80z TT000000 0 OTT qdd Ig 8 60 38SvS C Sc 3Z T 9T 3P 079 T vtc 3v6cvEe T 80 395907 7 72 20Z Sc00000 0 uMou xurn I0 30Z I I0 30Z7 I I0 300 1 e Zoc I ec Z07 SZ00000 0 S c wdd Se dd c8 60 3 ECLT vc av vI 34 0 6 VvCtdV6cvE T OT dELZV6 O E9E vOC CvT1000000 0 uMwouxun 00 30t 00 30t V0 300 Z ELSE POT c EE8E v0c v 1000000 0 cv qdd zc LL I8 L0 3c9 08 4 cc 39 ST 3E vS40 C vtct3v6cvE T 60 drrySrS T 6800 T 000000 0 uMou xurn c0 397 Z0 39Z E
22. LaCla gamma ray scintillation detector iv He thermal neutron detectors v He epithermal neutron detectors i BNC and HV cables NOTE Depends on detectors being used for the experiment 2 Uncover the Granite or Basalt monument by removing the rope and the tarp and placing them next to the granite You will need to recover the granite with the tarp and secure it with the rope when you are finished doing experiments for the day 3 Take the Equipment to the monument i PNG in the white box li Radiation detectors i e gamma ray and or neutron detectors ii Lynx DSA s iv Ethernet switches v BNC HV Ethernet and power cables necessary for the equipment being used PNG Operations Manual 02 02 201 1 P age 3 of 8 127 4 Setup the power communication and PNG interlock cables a Power cable setup i Take one orange power cable out to the monument and attach one end of the cable into the power outlet box located near the granite monument li Take the other end of the power cord and attach the short orange power cord with 3 outlet plugs to the power cord iii Attach two power strips to the short orange power cord with 3 outlet plugs and place them next to the granite b Ethernet communication cable setup i Locate the two red Ethernet cables located on spools inside Building 206 on the telescope platform near the stars to the right of the door as you enter the building li Insure that one Ethernet cable is connected to the s
23. Material 43 Lunar and Planetary Science Conference No 1544 2012 PING was tested on a total of 10 experimental rock configurations summarized in Table 1 of Chapter II and provided in more detail in Appendix II to determine the sensitivity to biogenic precursor elements e g C O and H and rock forming elements e g C H O Si Ca Fe Al Mg K Th and U necessary to unveil the volatile and organic nature and basic geochemistry of C type asteroids Determining the elemental concentrations as well as subsurface features in these most primitive asteroids will aid in answering important questions about the early history formation and evolution of the Solar System and Earth While not all of the experimental data collected with PING for these 10 configurations have been analyzed in this thesis the data are summarized in Appendix II Instead only the granite monument basalt monument and asteroid simulant configurations were selected for analysis These configurations were strategically 76 selected because one must understand the bulk properties of our selected granite and basalt standards before one can interpret results from more complex layering configurations using basalt granite and polyethylene materials The additional data collected for the remaining 7 configurations will be presented in future journal article publications The gamma ray and neutron experimental and MCNPX data were analyzed to determine the ratios o
24. SEA LT 39 IT 8 VC 3 07c8S I Z0 36S8CT S 1966 IS S0 349999 7 uwou xun 00 30T 00 30T v0 300 9 I966 IS 9 1966 te S0 3 9999 Z 29999999 9Z oz e ep 2iu1e485 aale eAe wdd SW SN4 90 JET6ES T tz 3v0 S LT IE8ESO E YZ 3E0Z8S T Z0 37 0 6 1 STY6 OS 90 d 8 6 umouyun 00 3t0 S lt Ee v0 300 T STv6 0S I sTv6 0S 90 JEEEER S ELEEELEES S S exep 21u1e485 994S eAe wdd dOI Shd 80 36S56t T Lc 3 6 8T 3 ZT06 T vC 3 078S T 90 380c071 Z8T7IO 6 GO JEEE8O T umou xun 0 307 6 0 307 6 90 300 Z8TZTO S Z8TZT0 6 S0 3 80 T EEES OT I eyep 5iueJ85 9974S ang wdd dOI Shd 90 3t7CV9 Z 7 4S9 Z 9T1 324046 6 vPC 3 078S I 80 34vCOE O T16S5S6 vv 90 d EE 8 7 uMou xun T0 3Ss9 7 T0 3S9 Z 90 300 8 T6SS6 vt L loteeeett 90 3EttE8 C EEEEEEB C I exep 2iu1e4e5 994S eAe wdd dOI Shd S0 3S2067 T 8Z IL Z 2 2 3698 v vC 3 0788 T S86S8020 0 0 v666 STI L 9447C 8y 0 uMouxun v0 307 7 v0 307 7 v0 300 vY666 ST v666 ST LE9LLZESY O 9 29 ees TO O sepiXO wouy O wns IM dOI Shd 90 4ZZ62 8 Sc 38 I 61 38 909 v VC 3 078S T S0 3p6TT6 7 197 6 0 9 6T06000 0 uwou xun I0 308 I I0 308 T 90 300 2 I9 46 0 Z T9ZEZ6 0E 9 6106000 0 41999999070 I0 0 SOZd 9o1 dOI Shd S 8982000 0 vc 3r9 61 386469 t vPc 3 078S8 T S0 398696 7 498 v vVTICVTOO 0 uMouxuf 00 3019 00 30T 9 0 300 T L98 ZV 798Zv vvTCVTOO 0 L9999TLEZ O TO O ZOLL gp dOI Sna 6 9 00 0 SEI
25. Tc 36vb6V T vPC 3 07c8S8 T S8SO0TTOO O 860 6 989EZEbO 0 uMouxun 00 350T Z 00 30T Z v0 300 T 960 6 1 860 6 989 7 v0 0 E807 S TO O OZA 991 ddI SN4 66v c9000 0 Sc 3v T7 4S285S T p7 5 078S T T8ZS86000 0 Z4686 7c Z8ETS9ZZO O uMwouxun T0 300 t T0 300 b 90 300 Z LL686 7Z c 024686 cc c8 TS9770 0 EEEEEEESO E I0 0 OZEN IM dOI Shd 87 901000 0 SC 3 v OZ IZZELY Z vc 3 078S8 T ZEE9STO00 O 8400r 9S80S592900 0 uMwouxun T0 30 v T0 30 v 0 300 t 8Z0 0t 7 8Z0 0b 98705929000 1999999 8 0 TO O 023 IM dOI Shd 90 3ST0ET Z 9z 3 9 OZ 3ZZTET T VC 3 0c8S I S0 368 ST SOE vZ vSZ8EZT00 0 umouxun 20 30 9 c0 30 9 v0 300 9 SOE vc 9 0so vc vSZ8EZT00 0 EEEEEE88Z O I0 0 OBW 991 dOI Shd 8Z0ST000 0 EZ JEE T 6T 5966Z1 T p7t HEO78S T 90 3bvCVT 4 6v08 6 vS 6 26 000 0 uMwouxun TO HEE T TO 3 E T 90 300 6 6708 6 vS 6 6v08 6 vs Z6 76E000 0 2999990S50 0 TO O OUN M dOI Sna vScSc8000 0 LEE Oz 36c9 7 vPC 3 078S T S9Sh0Z000 0 Sv8 SS S6E CvTTO 0 uMouxun 00 3SS 2 00 4SS 2 0 300 2 Sv8 SS c sv8 ss S6EZHTTO 0 EEEEEEEE9 T TO O 1 0294 1M dOI Snd 89 66000 0 Sc 3E c TZ 59LLEE b vC 3 078S T T68T1p 200 0 8EST86 9Z 97v086 0 0 uMou xun T0 30 Z I0 30 Z 90 300 2 8 ST86 9c Z 8EST86 9Z X 97v086 40 0 ELEEEBLE T TO O EOZIY M dOI Shd 8 v80 00 0 Sc 39 T 2 366 26 T vc 3 078S8 T 99 98T710 0 Gg gc EvILZZvE 0 uMou xun T0 309 T T0 309 T v0 300 SS80 87
26. Test Facility at NASA s Goddard Space Flight Center 41st Lunar and Planetary Science Conference 41 p 2581 2010 An outside neutron and gamma ray instrumentation test facility was constructed at NASA GSFC to evaluate conceptual designs of gamma ray and neutron systems that are intended to be proposed for future planetary lander and rover missions We describe this test facility and its current capabilities for operation of planetary in situ instrumentation utilizing a 14 MeV pulsed neutron generator as the gamma ray excitation source with gamma ray and neutron detectors in an open field with the ability to remotely monitor and operate experiments from a safe distance at an on site building The advantage of a permanent test facility with the ability to operate a neutron generator outside and the flexibility to modify testing configurations is essential for efficient testing of this type of technology Until now there have been no outdoor test facilities for 20 realistically testing neutron and gamma ray instruments planned for solar system exploration The test facility at GSFC shown in Figure 5 consists of two 1 8 x 1 8 x 0 9 meter Figure 5 Aerial view of GGAO This schematic of the outdoor gamma ray and neutron T fety f P Pr instrumentation testing d facility shows the operations control building as well as the 47 m diameter safety perimeter surrounding the two existing 1 8 m x 1 8 m x 0 9
27. Z TO 4SS Z S0 400 7 VESC6 8ST C vESC6 8ST 240000000 cL I0 0 wdd SW SN4 qL S9 VLVELECO0 0 07 36 v 9T 3C8 v8 b7 579079 T 80 3 8886 7 SC Z ST V00000 0 umouxun v0 306 v0 306 t 0 300 SC 4ST SC ZST V00000 0 Lv Top wdd SW SN4 po v9 S0 3CSTvC 8 Ic 39 v 9T 3P9T6 T Vc 3c9079 1 80 IZSSOT T 96 TST 89100000 0 uMouxun 0 309 v 0 309 v 0 300 T V96 TIST I v96 TST 89100000 0 89 T S00 0 wdd SW SN4 n3 9 vOZESE000 O T7Z 38 S 91 324680 9 vZ 4Z90Z9 T 80 3S9 SZ X 9O9E OSI S 9S00000 0 uMouxur 0 308 S 0 308 S 20 300 oC Ost E 9E OST S9S00000 0 S9 S I0 0 wdd Sw sn4 ws z9 S0 JTHE9 T EZ JS0 S LT IS8SEZ E Vc 3729079 1 40 379966 1 vcCvVvI 8820000 0 uMouxur TO 3S0 S I0 3S0 S 20 300 VC vVT e vv 8820000 0 EN S0 0 wdd SW SN4 DN 09 LO 3vvTTE 6 c 3ST T 91 316960 8 VPC 3Cc9079 1 80 48T966 h 9 06 0vT 0Z00000 0 uMouxur TO 4ST T TO 4ST T S0 300 2 S9 06 0vT 2 89406 0tT 70400000 0 v0 I0 0 wdd SW SN4 Jd 6S 10 348480 t SZ J3 9 LT 38988v 9 PC 3C79079 1 Z40 3 8 00 ott Ott 19500000 uMouxun I0 30 9 I0 30 9 0 300 T 9TT ObT T 9TT OPT 19850000 0 La S0 0 wdd SW SN4 92 8S 90 3vc61 2 vc 3vT 6 LT431S 6 2 b 479079 T LO A8ZSE8 T SS06 8 T sSz0000 0 uMouxun 00 3vT 6 00 3PT 6 v0 300 2 SS06 8 T Z SS06 8ET SSZ0000 0 ENER S0 0 wdd SW SN4 e1 LS 90 384690 S vc 3c 1 8T 328vCZ V vPc 3c9079 1 90 3c69097 SEET 8S 000 0 uMouxuf 00 307 T 00 307 T 0 300Z ZE LET LEE GET 8S 000 0 ger wdd dOI Snd eg 9S 80 IZ9ES E c 36 c ST 3
28. a 50 pulsed neutron generator synchronized with gamma ray and neutron detector data acquisition combined with the ability to post process acquired time tagged event by event data A unique benefit of incorporating a pulsed neutron generator with a time tagged event by event data acquisition system is that regions in time containing suspicious data can be isolated and removed from the data set for further inspection without affecting the usefulness of the remaining data Systematic errors in data are nearly impossible to anticipate but often can be identified when examining the post processed data Examples include systematic errors caused by equipment operating parameter changes such as temperature effects on a detector response or as illustrated in the data shown in Table 4 below changes in the time dependence of the turn on of neutron induced gamma ray flux that occurs during the PNG burst period Table 4 Fast neutron induced count rate and uncertainty for the 6129 keV O n n y gamma ray peak for ten time slices during the PNG pulse Time Time Uncertainty Range Slice iis cts us EMEN Or a ee I I 6 50 60 42 23 LB 050 Is dT d o X 9 80 90 46 a We demonstrate the merit of saving event by event time and energy data with our H I I I I analysis of the gamma ray count rate of the 6129 keV peak from neutron inelastic scattering on Do for a 2 hr live time gamma ray acq
29. be stable on geologic time scales the observed ice must have formed been exposed or delivered very recently Since ice is expected to be stable a few meters to a few tens of meters below the surface of 24 Themis 16 such an ice layer may serve as a reservoir replenishing the exposed ice through slow sublimation and re condensation on the surface and near subsurface as suggested by theoretical models of the main belt comet 133P Elst Pizarro 17 These recent observations coupled with ground based meteorite analysis suggest that our current understanding of C complex asteroids is very limited Understanding their elemental composition is a key component to understanding their formation and evolution and can also provide information that will help scientists better understand the origin formation and evolution of our Solar System and possibly the biogenic precursors that may have sparked the life on Earth Therefore a technique that is capable of making bulk surface and subsurface elemental composition and water ice depth measurements would not only be well suited to testing this hypothesis by evaluating the abundance and composition of ice and other volatiles in the near subsurface but we can measure the properties of the meteorites on Earth to strengthen the connection between C complex asteroids and carbonaceous chondrites leading to a greater understanding of how the planets were formed since asteroids are the most primitive bodies in the
30. characteristic gamma rays emitted by the excited nuclei and 3 neutron detectors to measure the count rates and energies of the neutrons that are scattered back up toward the surface The combination of a PNG with gamma ray and neutron detectors has been used to measure elemental composition in the oil well logging industry for many decades 33 34 While there is an extensive literature 33 35 36 37 38 39 40 about how to carefully map and quantify elemental compositions in the down the borehole geometry of an oil well there have been limited efforts to apply this technology to measurements made from the surface 41 42 43 44 45 B 46 477 12 We note that PING differs significantly from the Dynamic Albedo of Neutrons DAN experiment on the Mars Science Laboratory MSL DAN is an instrument designed to detect subsurface hydrogen water while PING is designed to determine the full bulk subsurface elemental composition of the regolith in addition to having better sensitivity to hydrogen as DAN since DAN doesn t produce enough neutrons to get to as low a level of uncertainty as can be done with a higher output PNG where this is from the combination of the number of neutrons per pulse times the number of pulses that can be produced for a single measurement The hardware configurations differ in two significant ways while DAN consists of its PNG and a set of neutron detectors PING includes a gamma ray spectromet
31. data set is in another corresponding tlistdata txt file The tlistdata txt files are in ASCII format and contain two columns listing the channel and time for each recorded event The filtered txt files are in ASCII format and contain header information describing the PNG gamma ray detector Lynx acquisition system settings time slice information and columns for channel energy and counts for either inelastic capture or delayed activation and natural activity gamma rays The thermal and epithermal neutron tlistdata txt logs are provided in ASCII format The PDF filenames provided in the subsections below list the log filenames and first two pages of the time sliced data files for all ten configurations Granite The available data for the Granite configuration is as follows e 111005Ge1TLTOOI log pdf e 121101GelTLTOOI 1 log pdf 121101GelTLTOO1 1 capture filtered pdf 121101Gel1TLTOO1 1 DANA filtered pdf 21101GelTLTOO1 1 inelastic filtered pdf e 121102Gel TLTOOI I log pdf 121 102Gel TLTOOI 1 capture filtered pdf 121102Gel TLTOOI 1 DANA filtered pdf 121 102Gel TLTOOI 1 inelastic filtered pdf e 121102Gel TLTOOI 2 log pdf 121 102Gel TLT0OI 2 capture filtered pdf 121102Gel TLTOOI 2 DANA filtered pdf 121 102Gel TLTO0I 2 inelastic filtered pdf e 121104Gel TLTOOI 1 log pdf 121 104Gel TLTOOI 1 capture filtered pdf I121104Gel TLTOOI 1 DANA filtered pdf 121 104Gel TLTOOI 1 inelastic filtered pdf e 121104G
32. different for Figures 44 45 and 46 due to the difference in the way each material moderates neutrons Tables 16 17 and 18 show the calculated macroscopic thermal neutron absoption cross section calculation spreadsheet for the granite monument the basalt monument and the asteroid simulant based upon an independent elemental assay Thermal Neutron Timing Histogram of Granite Monument x He thermal n detector k Double exp fit LOG COUNTS 200 400 T 800 10D0 TIME user Fastn Epithermal Thermal n Diffusion n amp Thermal n Figure 44 Experimental thermal neutron dieaway results and fit for the granite 91 Thermal Neutron Timing Histogram of Basalt Monument He thermal n detector Double exp fit Single exp fit Single exp fit 1000 LOG COUNTS 0 600 800 10b0 TIME psec Fastn Epithermal amp Thermal n Diffusion n Thermal n Figure 45 Experimental thermal neutron dieaway results and fit for the basalt Thermal Neutron Timing Histogram of Asteroid Simulant He thermal n detector Double exp fit 4o LOG COUNTS 9 8 7 6 600 800 1000 Fastn Epithermal Thermal n Diffusion n amp Thermal n Figure 46 Experimental thermal neutron dieaway results and fit for the asteroid simulant 92 cO0 3vVT T 908S28066 0 OT 3ISS9S Z Sc 3C S VI 389 6 v VC 3 07c8S T OT 3 S8TT E 990 C 10000000 0 umouxu
33. el sof wl en d al a EAST SIDE CERAMIC lt 10 al d af d ei d an al mal d al a WesTSIDE cERAMIC lt 10 el ad 14 5 el ed oa wel ad 2 nl a paver ceramic IL d wl al d d ei ad ol wl ai 2 al a ee AmayteSymbo S al oe sw Go a wl Sm o al m ty paver wf oaj maj aof od mi d oa od 0 505 4s3 oss zm REESEN Analyte Symbol Ho E amp m ww ww m ee e wu paver os 154 zelt ei oaf 43 18 a d al osf aal aa paver ceramic ose el ozaj asoj oas velo a el si d al ai 106 APPENDIX II EXPERIMENTAL ROCK CONFIGURATIONS PING was tested on a total of 10 experimental rock configurations to determine the sensitivity of the instrument to elements necessary for biogenic precursors such as C O S and H and major rock forming elements to help reveal the volatile and organic nature and bulk geochemistry of C type asteroids and differentiate between different asteroid classes The 10 experimental rock configuration images layering grids PING component spacing measurements notes neutron and gamma ray experimental data logs and post processed time sliced data are presented in this appendix Table 22 lists all of the data acquired using PING on top of the 10 experimental rock configurations Table 22 Raw TLIST gamma ray thermal and epithermal neutron data collection totals for data acquired with PING on the 10 experimental rock configurations Hel and He2 refer
34. experimental value is due to the real presence of carbon and not the carbon counts coming from the element O Further work on refining the Monte Carlo model to account for the counts due to the equipment especially in the Al and Fe peaks will be pursued in the near future Neutron The thermal neutron dieaway data was analyzed for the granite basalt and asteroid layering configurations and compared to their elemental assays to determine the thermal macroscopic neutron absorption cross sections of each configuration The dieaway curves were each fit with a double exponential due to the fact that there are 90 competing neutron processes shown during different time intervals as indicated by fast neutron epithermal and thermal neutron thermal neutron and neutron diffusion The 14 MeV fast neutrons slow down through the process of elastic scattering off of elements in the regolith producing epithermal neutrons that are further slowed down through inelastic scattering that then results in thermal neutrons that can be captured by other elements and final neutron diffussion occurs since no all neutrons that interact in the regolith are absorbed Figures 44 45 and 46 show the fitted thermal neutron dieaway for the granite monument the basalt monument and the asteroid simulant displayed as a fuction of time during the PNG pulse period x axis and number of neutrons detector in counts y axis The thermal neutron region of the exponential fit is
35. for time slices 1 through 10 t 0 100 us which is 40 1 cts us 0 82 cts us The difference between these two averages is two times the statistical uncertainty resulting in a systematic error that would compromise the accuracy of derived elemental concentrations Energy Calibrating Spectra Using Igor Pro 6 2 Software PING time sliced TLIST data are analyzed by using the Igor Pro 6 2 Software and procedures created by Dave Hamara at the University of Arizona in Tucson Arizona The raw TLIST data are initially processed to obtain y ray spectra in different time regimes e g inelastic scattering capture delayed activation and natural activity time windows relative to the neutron pulse to minimize spectral interferences This is done 53 because some spectral interference can be eliminated by subtracting peaks in one region from the same peak in other regions to eliminate contributions when the same energy peak can be created from a different element Each set of data for a defined time window acquired on a physical rock configuration with the same PING prototype set up is then individually energy calibrated and interpolated to put all spectra on the same energy scale using Igor Each spectrum is individually calibrated because of the different outdoor conditions that occur due to variations in temperature humidity during different times of day and time of year that data were collected The basic energy calibration for each spectrum fo
36. in Remote Geochemical Analysis Elemental and Mineralogical Composition Topics in Remote Sensing 4 Carle M Pieters and Peter A J Englert Eds Cambridge University Press 34 Herron S L et al 1993 Remote Geochemical Analysis Elemental and Mineralogical Composition eds C M Pieters and P A J Englert pp 507 537 Cambridge University press New York 35 Ellis D V Schweitzer J S Ullo J J 1987 Nuclear Techniques for Subsurface Geology Ann Rev Nucl Part Sci 37 213 36 Grau J A Schweitzer J S Ellis D V Hertzog R C 1989 A Geological Model for Gamma Ray Spectroscopy Logging Measurements Nucl Geophys 3 351 37 Grau J A Schweitzer J S Hertzog R C 1990 Statistical Uncertainties of Elemental Concentrations Extracted from Neutron Induced Gamma Ray Measurements IEEE Trans Nucl Sci 37 2175 38 Hertzog R Colson L Seeman B O Brien M Scott H McKeon D Wraight P Grau J Ellis D Schweitzer J Herron M 1989 Geochemical Logging with Spectrometry Tools SPE Formation Evaluation 4 153 39 Schweitzer J S Ellis D V Grau J A Hertzog R C 1988 Elemental Concentrations from Gamma Ray Spectroscopy Logs Nucl Geophys 2 175 40 Schweitzer J S 1991 Nuclear Techniques in the Oil Industry Nucl Geophys 5 1 2 65 41 Mills Jr W R Givens W W Neutron Die Away Experiment for Luna
37. labeled Beam Control and HV Control on the main GUI interface DNC t S f Fie Screen Abo Beam Current nA 0 3 High Voltage kV 0 Getter Current A 1 75 50 0 50 100 150 2 00 00 mu Beam Cunent Pulser Internal B wg m 10000 Hz D on Nomad 15 0 DF Neutrons Mode C n 0 160 J 0 State Totalizer Beam Control HV Control E IDLE ummerm EE Exposure 2555340 Mr Interlock Tee 00 00 00 d Setting 00 00 00 P 385 wi mmm Thermo SCIENTIFIC Figure 11 PNG Main GUI Display b The Beam Current A High Voltage kV and Getter Current A status boxes along the top of the main GUI interface will display the current values for the PNG when it is Off or On and producing neutrons 3 Setup the Pulser a Click on Pulser Setup on the Screen pull down menu tab and the Pulser Setup window will pop Enter in the PNG settings for frequency and duty cycle into the boxes for your experiment Additional options are available in this window including configuring the PNG pulse timing and selecting an external pulse source b Figure 11 shows an example of the Pulser Setup window with the two buttons that allow you to save the setup greyed out and not available You must first click on the File tab enter the TMFP password and press the Enter button on your key board to configure the pulse options to prevent the system from being accident
38. m granite and basalt monuments Basalt Monument Granite Monum structures of granite and basalt in the middle of an open field with an approximately 50 m radius radiation safety perimeter A soil profile was conducted shown in Figure 6 to determine what the drainage would be like in the field and what kind of foundation was necessary support the granite and basalt monuments The composition of the soil was predominately sand and clay so it would provide good drainage As a result of the soil profile and consultation with George Pellettieri president of Pellettiere Associates Inc landscape architecture amp construction in Warner NH it was decided that both the granite and basalt monuments would be supported on 2 4 x 1 2 m horizontally placed posts that are placed on top of a crushed stone circular area of 3 1 to 3 7 meters in diameter and 31 cm in depth 21 pre Ecol ia G Ze eil l pn Hai GRR ae O G f ae ny ei LAN Bled en d wv e z Q0 j Y rx WM t L4 O 7 x PALE d PS E C if le em ee ne a n ie a Ak DHE K Oe ren 1 HH D j lt gt Le e d a gem T 2 Le V 7 d e HF Um m Wi FE i FO 3 o Figure 6 A drawing of the soil profile performed by Gunther Kletetschka and Julia Bodnarik on their shoveled out 0 9 m x 0 9 m x 0 6 m meter pit in the middle of the field at GGAO with 2 1 m t
39. pdf 120313Gel1TLT001 DA NA 16 2 650 1 999 9us filtered pdf 120313Gel TLTOOI inelastic filtered pdf 115 2 3 120314Ge1TLT001 1 log pdf 120314Ge1TLT001 1 DA NA 17 9 650 1 990 O0us filtered pdf 120314GelTLTOO1 1 inelastic filtered pdf 120314Gel TLTOOI 2 capture 17 9 150 650us filtered pdf 120314GelTLTOO1 2 log pdf 120314Gel TLT001 2 DA cNA 17 9 650 1 999 9us filtered pdf 120314GelTLTO001 2 inelastic filtered pdf 120314Gel TLTOOI capture 17 9 150 650us filtered pdf 120315Gel TLTOOI 1 log pdf 120315Gel TLTOOI 1 capture 18 150 650us filtered pdf 120315GelTLTOO1 1 DA NA 18 650 1 999 9us filtered pdf 120315Gel TLTOOI 1 inelastic filtered pdf 120321 Ge1 TLTO00I 1 log pdf 120321 Gel TLTO0OI 1 capture 17 150 650us filtered pdf 120321GelTLTOO1 1 DA NA 17 650 1 999 9us filtered pdf 120321GelTLTOO1 1 inelastic filtered pdf 120321GelTLTOO1 2 log pdf 120321 Gel TLT001 2 capture 17 150 650us filtered pdf 120321 GelTLT001 2 DA NA 17 650 1 999 9us filtered pdf 120321Gel TLTOOI 2 1nelastic filtered pdf 120322GelTLTOO1 1 log pdf 120322Ge1TLTOO1 1 capture 18 150 650us filtered pdf 120322GelTLTO0O1 1 DA NA 18 650 1 999 9us filtered pdf 120322Gel TLTOOI 1 inelastic filtered pdf 120322GelTLTOOI 2 log pdf 120322Gel TLTO0OI 2 capture 18 3 150 650us filtered pdf 120322Gel TLT001 2 DA 4NA 18 3 650 1 999 9us filtered pdf 120322Gel TLTOOI 2 1nelastic filtered pdf 120322Ge1TLT002 log pdf 120322Gel TLT002 capture 18
40. properties but more sophisticated MCNPX models are needed to properly model PING experiments The benchmarked Monte Carlo model can then simulate PING measurements on asteroids which could be used to determine bulk asteroid properties differentiate between asteroid types and thus strengthen their connection to meteorite compositions This research firmly establishes that PING can obtain important geochemical information on asteroids from neutron transport and elemental analysis A future asteroid mission with PING will have substantially increased science return providing a direct subsurface regolith description without needing to drill or disrupt the surface We have demonstrated that compositions for specific asteroid types can be fabricated in large volume structures on Earth permitting experiments with a benchmarked Monte Carlo program to predict mission responses to optimize the science return prior to launch Approved Keivan G Stassun Ann M Parsons USING IN SITU NEUTRON AND GAMMA RAY SPECTROSCOPY TO CHARACTERIZE AND DIFFERENTIATE ASTEROIDS by Julia Gates Bodnarik Dissertation Submitted to the Faculty of the Graduate School of Vanderbilt University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Physics May 2013 Nashville Tennessee Approved Keivan G Stassun Ann M Parsons Jeffrey S Schweitzer Arnold Burger Kelly Holley Bockelmann David J Ernst Copyright
41. state The PNG must be producing neutrons to allow you to enter standby C To exit standby mode and return run mode toggle the Mode switch from the STANDBY position to the NORMAL position USE CAUTION Although the PNG is not producing neutrons in Standby mode HV is still applied and the tube has sufficient pressure to make neutrons as soon as the ion voltage is applied It is not recommended to use this setting for activities that would put personnel in close proximity to the PNG The system can resume neutron production immediately upon exiting the standby state and returning to the idle state by simply toggling the Neutron switch from the OFF position to the ON position on the main GUI display 6 Stop the PNG a To stop neutron production and fully turn off the PNG Toggle the Neutron labeled software switch from the ON position to the OFF position b Stop the PNG when before you make changes to the PNG settings when personnel is in close proximity to the PNG or when you are done with your experiments Wait approximately 20 30 minutes before going out to the granite or basalt monument with a gamma ray detector to avoid exposure to a high flux of delayed gamma rays from the monument NOTE For additional information please consult the Thermo Scientific MP320 PNG Manuals PNG Operations Manual 02 02 201 1 Page 11 of 11 143
42. the elemental building blocks from which the planets were formed Studying the organic and inorganic geochemistry of these ancient bodies can provide a window into the formation and evolution of the planets and the origin of life itself Ongoing geochemical studies of primitive asteroids have been a critical contributing factor governing present models of planetary formation and solar system evolution Carbonaceous asteroids spectral type C or C complex are of particular scientific interest since they are a possible source of Earth forming planetesimals and contain volatiles water and organic materials that could be biogenic precursors This evidence primarily comes from two sources including carbonaceous chondrite meteoritic studies and telescopic observations of C complex asteroids However these sources reflect observations from widely contrasting spatial scales presently yielding a void in the continuum of microscopic to macroscopic evidence The link between the mineralogy and elemental composition of carbonaceous chondrite meteorites and C complex asteroids 1s tenuous and unclear since one is comparing the measured composition of the bulk of these meteorites with micron thick surface composition measurements of these asteroids and the asteriod surface measurements may not be representative of the bulk composition of the C complex asteroid Therefore it is very difficult to determine which meteorite came from which type of asteroid requiring d
43. this previous work due to the lessons learned after reviewing the PTC tests as well as earlier work on calibrating the NEAR 17 detector performed in a geometry that was much closer to the approach taken here This work was conducted using a new PING prototype constructed from off the shelf components and tested outdoors at a facility that was constructed near NASA GSFC This test site provides two known well characterized meter sized standard rock monuments and various layering configurations on the top of the monument using rock and polyethylene tiles as explained 1n Chapter II Testing of PING on an Asteroid Simulant In order to optimize PING for an asteroid lander it needed to be tested on a known and well characterized meter sized asteroid sample or analog material simulant Ideally one would like to use 3 m of primitive carbonaceous chondrite meteorites analogs to C type asteroids However there are currently only 9 of the most primitive carbonaceous chondrite meteorites in existence on Earth a total amount of approximately 2 kg so a simulant was constructed An appropriate asteroid simulant must have nearly the same neutron response as the C type asteroid to be studied The asteroid simulant must have an equivalent neutron spatial distribution within the volume similar neutron moderation properties and equivalent neutron absorption processes similar average macroscopic neutron absorption cross section as that of a C typ
44. to the 3He thermal and epithermal neutron detectors UT stands for the detectors borrowed from the University of Tennessee and Navy stands for the detector borrowed through Stan Hunter from the Navy HPGe Bare 107 Date 3 23 12 3 26 12 3 29 12 3 30 12 4 6 12 4 8 12 4 10 12 4 11 12 4 12 12 8 23 11 8 24 11 9 30 11 4 00hrs pn Note Shift in timing data at 83 minutes 108 Date He2 UT 2 26 12 N A 2 27 12 N A 2 28 12 N A 3 1 12 N A 8 83hrs N A 4 15 12 4 00hrs 4 16 12 5 98hrs 4 17 12 5 00hrs 4 18 1 1 32hrs 4 19 12 N A 4 24 12 N A 4 25 12 N A N A 18 58hrs 1200hrs 1630hs Date HPGe Bare HPGe Boron Cap Hel UT Hei UT NA N A NA N A JN HPGe Bare HPGe Boron Cap He1 Navy He2 Navy 5 7 12 N A 4 37hrs 4 47hrs N A NA Date HPGe Bare HPGe Boron Cap He1 Navy He2 Navy Date 4 15 12 4 16 12 4 17 12 4 18 12 4 19 12 4 24 12 4 25 12 The HPGe gamma ray raw TLIST data logs and portions of the time sliced experimental data for inelastic scattering 10 100 us capture 150 650 us and delayed activation and natural radioactivity 650 1000 us for all 10 configurations can be acquired upon request from the author The raw tlist txt data log files are in ASCH 109 format and list the parameters and settings for the gamma ray detector PNG Lynx acquisition system settings and indicate that the master raw
45. wdd SW SN4 L0 3487 EZ JTT Z 9T IZS86S T vC 3 078S8 T 80 37POTO T 6Zv6 08T 90 3 828 T uMouxuf TO JTT Z TO JTT Z v0 300 T 6Lv6 08T 1 6276 08T 90 3 828 T E 828 T TO O e ep drue 994S aoAp wdd SW SN4 90 3 v748 7z 3C0 T 9143896 vPC 3 078S8 T 80 39266 72 GESAT 90 3 87 uMouxun ZO 3Z0 T ZO 4Z0 T Z0 300 Z 6b SZT Z 6p 8ZT 90 3 87 t 9c v ro e ep Diwesad 994S ang wdd SW SN4 Z0 4Z60ST T GEN ST 3688p T vPC4 3 078S T OT 3 TTIV 6 L96 v T L0 3499p9 T uwouxufi TO HEL L TO HEL L 0 300 T L96 vLT 1 296 vZT L0 3499v9 T 49999979T 0 z00 0 e ep 5iue482 994S ang wdd SW SN4 80 3900TS S 2 399 ST 38vS0S T vPC 3 0728S T OT 3I9TS 6 vO ELT Z0 4L9979 T uwouxuf T0 399 TO 399 c0 300 bO ELT vO EZT 90 3 99v7 1 L999999v7 T TO O e ep 5iue485 994S ang wdd SW SN4 90 3S207 T 7Z 3E0 T 9T 38vL9T T vPC 3 078S T 60 396 4 TZvE6 SOT 90 3 99pZ T uMwouxun ZO 3 0 T ZO 5 0 T S0 300 Z Tcvt 6 89T c Tevt 6 89T L0 3SCT 7 ScTC O S00 0 e ep 5iueJ85 994S ang wdd SW SN4 L0 IT9SZ E ZZ 3Z9 T ST 3VF6600 Z vPC 3 078S I 60 38t0 7C 1 92 Z9T L0 3SZT 7 uMou xun c0 379 1 ZO 4Z9 T 0 300 9c 49T 97 Z9T 90 FEEE6H T CLELCEELSH T TO O e ep JJwesad jaajs ang wdd SW SN4 L0 3 9S7S 6 7 3S9 9 9TI 3EvCEV T VPC 3 078S T 60 3 E vS0 6 CEOE6 v9T 90 dE 6p T uMouxun I0 3s9 9 T0 389 9 S0 300 c ZEOES HOT Z ZEOE6 POT L0 3499TE S Z99
46. weight percent values from the data This is done by normalizing all elements to Si so that one can compare them to the MCNPX inelastic window ratios Tables 13 14 and 15 list the gamma ray experimental and MCNPX ratios for the granite basalt and asteroid simulant Each table consists of 5 columns showing the isotopic ratio identifications Ratio the experimental ratio Exp Ratio between each gamma ray line Si gamma ray line for all gamma rays listed in Tables 10 12 the uncertainty of the experimental ratio with relative uncertainty 6 in units of the MCNPX gamma ray line ratios MCNPX Ratio corresponding to the same gamma ray lines in Tables 10 12 and the relative uncertainty of the MCNPX ratio o in units of As seen in Table 13 for the PING granite experiment the Na Si experimental isotopic ratio and uncertainty is 0 233 5 67 as compared to the MCNPX ratio and uncertainty that 1s 0 026 37 79 Even with the large uncertainty associated with the MCNPX ratio the two ratios differ approximately by a factor of 10 The Al Si experimental ratio as compared to the MCNPX ratio is 0 738 1 14 and 0 119 4 69 differing by approximately a factor of 6 The Fe Si experimental and MCNPX ratios and 85 uncertainties are 0 561 1 15 and 0 043 7 88 differing approximately by a factor of 10 The C Si experimental and MCNPX ratios and uncertainties are 0 181 3 82 and 0 100 3 12 differing approximately by a factor of 1 8 The O S
47. workers as the major source of Earth s present water inventory 6 based in part on the similarity in isotopic composition between the hydrogen in the Earth s oceans and in the water in these carbonaceous chondrites Matching these primitive meteorites to their asteroid parent bodies 1s thus very important to the understanding of the origin and evolution of the planets in our solar system Currently the best candidates for the parent bodies of carbonaceous chondrites are C complex asteroids 7 8 assigned by the Bus DeMeo asteroid classification taxonomy 9 10 Unfortunately VIS and NIR spectroscopy of C complex asteroids provides limited compositional information since their spectra are relatively featureless and the emission is very weak in this wavelength band Perhaps the strongest evidence for a compositional relationship between C complex asteroids and carbonaceous chondrites comes from reflectance spectroscopy of the OH absorption features in the 2 7 3 5 micron region 11 12 13 Most although not all C complex asteroids have a substantial water of hydration feature that is similar in spectral shape to that found in the spectra of CM Mighei like carbonaceous chondrites and attributable to bound OH in phyllosilicates Ground based spectroscopy in the 3 micron region has also recently provided evidence for water ice and organics on the surface of asteroid 24 Themis 14 15 Since the surface of this asteroid is too warm for ice to
48. y Mn n yp a 8 E o NO Bei Si n pp 40554 7 Al n yp 28668 Fe n pB Mn n yp Fe n pp Mn n yp ON N N N 2614 Th 20 T 2783 7 94 26797 28TH OT 18979 1438 mas a p 16 6129 arm 23470 0 98 fO npB 5019 L81 O npB 3450 2 17 bea KH 0 78 MEN 8l Table 8 Gamma ray line intensities and uncertainties for the basalt monument data with the HPGe detector wrapped in a borated rubber cap for different timing windows during the PNG pulse period total acquisition live time 15 23 hrs The that it is the excited state of the isotope 1 e 2 Mg through the Sim Mg reaction Inelastic Scattering Window Thermal Neutron Capture Window jen cts 2089 7 24 70 Fe n pp Mg n y Mn n yp 5893 24065 66399 symbol means x Mg means that it is the excited state of Delayed Activation amp Natural Activity 96 cts 69m 119 Geck 228TH _ 20877 Fe n pB Mg n yB Mn n yp a tet P ON 5399 4 97 1963 8Si n pB Si n pp Ala 27212 TAIB MK 19156 Fe n pp Mn n yp Manz 361 2211 An n y 2223 H n y 43443 2614 Th 2i 4438 11089 16 6129 Gran Y 52465 O n pp mene o 2311 NEN i 30 m E Es O N 00 N 5 IA No o l O npB 4427 1 96 S O n pp 3060 2 31 82 Table 9 Gamma ray line intensities and uncertainties for th
49. zo 300 Z 65 00Z c es 00c T 000000 0 OTE qdd SC 5H 08 80 319 97 6 7 388 6 vPI 3VvC988 6 b7 dv6Zve l OT H99T9 7 S8996 96T SbT000000 0 uMouxun T0 388 6 I0 388 6 S0 300 2 GS996 96T Z SS996 96T Sv1T000000 0 SbT qdd gue ny 64 80 311v88 9 z 3T ST 31Tv088 9 VC 3v6CvE T 60 38T97T S 8 0 S6T T00000 0 uMou xun T0O 300 T T0 300 1 0 300 c 8Z0 S6T Z 8Z0 S6T T00000 0 I wdd ld 8Z 90 346 8 T cc 397v ST 39 8v7 vc 3V6CvE T 60 dvT6Tp C LTC C6T S95000000 0 uMouxun c0 397c 20 397 v 0 300 LTC C6T LEI zer S9 000000 0 Got qdd s JI LL 80 J SZ6Z S EZ JES T ST 38T6Sv Vc 3v6cvE T 60 JE8SZS Z7 EC O6T 67000000 0 uMouxun TO 3ES T IO 3ES I 20 300 CZ oer c 06T 61000000 0 06v qdd Se SO ER 80 3CATTv C c 38 8 bT 36S0bZ Z vc 3Vv6cvE T OT dp 0vO c Z0c7 98T 8 0000000 0 uMouxun T0 308 8 T0 308 8 0 300 T LOZ 98T T ZOZ 98T 8 0000000 0 8E qdd T eu SZ 80 3189S7 T 7 4S8 T bT 38S 62 9 VC 3V6CvE T OT H3S 8S0 8 gest 60000000 0 uMouxun TO 3S8 I I0 3S8 I Z0 300 T v89 8T I r8 E8T 60000000 0 6 qdd E M bl 60 39 C6T C EZ JTT Z tT 3v06 0 T VC 3v6CvVE T TT HEOLEL L 6Lv6 081 10000000 0 uMouxun TO JTT Z TO JTT Z V0 300 T 6Zv6 08T 1 6Z76 08T VT0000000 0 FI qdd SC SL Z 80 3808S0 8 cc 3c0 1 bT 380006 2 VC dV6CvE tT OT H89788 8 6V 8 T S0T000000 0 uwouxun ZO 4Z0 T ZO 4Z0 T Z0 300 Z 6b SLT c 6v 841 S01000000 0 SOLO wdd ges JH ZL 80 3 7E8v T 7 3 L 4 PTI 3v8816 T bT AP6ZvE T OT H0887V T 4 96 v
50. 00 Z8TZIO S Z8TZT0 6 60 4S Z S200 0 wdd Se eg v 90 3 50 9 t 7 4S9 Z LI ALbZ9L T VC 3v6CvVE T LO AvZTE t T6SS6 vt 6S00000 0 umouxun TO 4S9 Z T0 3Ss9 c 90 300 8 T6SS6 vt 8 OT6SS6 vP 6800000 0 6 S wdd m 2S TZ S0 39STSO T 8c 3aZ c CC 349v68 vC 3v6cvE T 880T006Z0 0 666 ST v9v O umouxun v0 307 C v0 307 C v0 300 v666 ST v666 ST v9v O vov 9 91M 0 8 90 360t Tv 4 Sc 38 T 6T 3P681T t VC 3V6cvE T SO ATTL90 T9ZEZL6 OE S6000 0 uMwouxun I0 308 T I0 308 I 90 300 2 I9 46 0 Z T9ZEZ6 0E S6000 0 0S6 wdd d ST S0 3CT0ES Z vc 3r9 6T 3SvvEC T Vct3v6cvEe T 90 3vTC6T 6 798 Zt bv000 0 uMwou xurn 00 3019 00 3019 0 300 T L98 V 1 298 Lb Vv000 0 Ott wdd LL ec S0 391796 GGG 6T 4ZT688 T Vc 3v6cvE T SO ATLZ90b T 960 6 SS000 0 uwouxun 00 30T Z 00 30T 7 V0 300 T 860 6 1 860 6 SS000 0 oss wdd Se z 6T 628911000 0 SZ 3v 0z 3 Z4026 7 VC 3v6cvE T 88p T7000 0 4468677 S00 0 uMwouxun I0 300 v T0 300 b 90 300 Z LL686 7Z Z 0Z2686 7Z S00 0 000s wdd eN TT T98 T000 0 ScC 3 v 0c 38v 7C vct3v6cvE T c 00vP2000 0 8Z0 0b c9600 0 umouxun I0 30 t TO J0 b 0 300 t 8Z0 0 v 820 0t 79600 0 c96 0 9 91M e 0c vS9 000 0 9c 3 9 TZ 56S6SE S b7 dv6ZvE T 8756066 000 SO F 260 0 uMou xun c0 30 9 c0 30 9 V0 300 9 SO vc 9 0s0 vc L60 0 6 9 91M BW ral 6TZ0 9000 0 EZ JEE T DEEN VC dv6cvE T SO JSZTES E 6v08 6 v5 v6T00 0 umouxun TO AEE T TO 3E
51. 000000 0 LS0 0 wdd eos ng 9 90 36 0Z7 Ic 38 S ST 3746 T VC 3v6cvE T 0T 3909 6 6 9 OST S1000000 0 uMwouxun 0 308 S 0 308 S 0 300 oC oer 9 OST S1000000 0 ST O wdd ws c9 L0 3I8C9T C 7 4S0 S DEEN VC 3v6CVE T 60 FET68T E vZ vVT 9 000000 0 uwouxun TO 3S0 S T0 3S0 S Z0 400 aaa rC vVT 97000000 0 9p 0 wdd PN 09 80 J9Z0 0 T EZ JST T tT 3648S6 8 Vct3V6cvE T OT Av0TZ9 9 89 06 0vT 60000000 0 uMouxuf TO 3ST T TO JST T sS0 300 Z S89 06 0vT c s9406 0v1 V60000000 0 v60 0 wdd ges dd 6S 60 369 t Sc 3E 9 STI 3 4ECV6 S Vct3v6cvEe T 60 dI6bCV v 9TT ObT 29000000 0 uMwou xurn I0 30 9 I0 30 9 0 300 T 9IT OvT I 9T1T OvT 29000000 0 z9 0 wdd ooo 92 8S 80 36859 0 c vc 3vl 6 GT 5861 L772 pZ Av6ZvE T 60 38169 T SS06 8 T S 2000000 0 uMouxun 00 3vT 6 00 3vT 6 v0 300 Z GS06 8ET Z SS06 8ET S 2000000 0 SEZ O wdd e LG 80 3IZZSZ C vc 3c I 91 36086c C VC dv6cvE T 80 HpCTTIZ T ZCE ZET S 200000 0 uMwouxun 00 3071 00 307 T 0 300 7 LCE LET LEE 4 1 S c00000 0 SEZ wdd eg 9S 80 39SZ9S S EZ J6 Z ST 3S86T6 T VC 3v6cvE T 60 36S862v T SPSO6 CET 61000000 0 uMwouxun T0 306 Z T0 306 Z s0 300 Z GvS06 ZET Z SvS06 ZET 610000000 6T 0 wdd Ee SG 80 3 7T78 C vpc 3c9 ST 38E 0SS v Vc 3V6cvE T 60 38 88 Zvv06 97T v000000 0 uMouxun 00 307 9 00 307 9 S0 300 Lvv06 92T Zvv06 97T 7000000 0 V 0 wdd I S LO 3IZZET T ETA 9T 39902v 7 VC 3v6cvE T 80 3I
52. 02 1log pdf 110930Hel1 TLT003 log pdf 110930Hel TL TO00O5 log pdf 110930Hel TLTO006 log pdf 120406Hel TLTOO1 1 log pdf 120406Hel TLTOO1 2 log pdf 110823He2TLTOOI log pdf 110823He2TL TO002 log pdf 110824He2TLTOOI log pdf 110824 He2TL T002 log pdf 110824He2TLT003 log pdf 110824He2TLT004 log pdf 110824He2TLT005 log pdf 1 10824He2TL TOOO6 1 log pdf 110824He2TLTOOO log pdf 110824 He2TL T007 log pdf 110824He2TLT008 log pdf 1 10930He2TLTOOI log pdf 120410He2TLTOOI log pdf 12041 1He2TL TOOI log pdf 120412He2TLTOOI 1 log pdf 120412He2TLT004 log pdf The available data for the 2 1 configuration 1s as follows 120226GelTLTOOI log pdf 120226Gel TLTOOI capture filtered pdf 120226GelTLTOOI DANA filtered pdf 120226Ge1TLTOO1 inelastic filtered pdf 120227GelTLTOOI 1 log pdf 120227Gel TLTOOI 1 capture filtered pdf 120227GelTLTOOI 1 DANA filtered pdf 120227GelTLTOO1 1 inelastic filtered pdf 114 e 120227Gel TLTOOI 2 log pdf 120227Gel TLTO0OI 2 capture filtered pdf 120227GelTLTO00OI 2 DANA filtered pdf 120227GelTLTOO1 2 inelastic filtered pdf e 120227GelTLT002 log pdf 120227Gel TLT002 capture filtered pdf 120227Ge1TLT002 DANA filtered pdf 120227Gel TLT002 inelastic filtered pdf e 120227GelTLT003 log pdf 120227Gel TLT003 capture filtered pdf 120227GelTLTO003 DANA filtered pdf 120227Gel TLT003 inelastic filtered pdf e 120228Gel TLTOOI I log pdf 120228Gel TLTO0OI 1 capture filtered pdf 120228Gel TLTOOI
53. 03e jueuus 4 Z O Aysuap ou 21018 SseuJ Je ouJ uonejue uoo uomnpes sso uondjosqe uoyn u euueu idoosoJ45luJ M uoiueduio5 S JSIVUSIDS A1 e1jaue d Uz is AOE loU Il YN xag IW IN el eo V LOL uonsoduJo je1ueuls 3 eapuou TIO JU DUIIS pIOI9 S 201 107 suone no eo uomnoos ssoJo uondosqe uoqmnou puy ordoosoJoeui pore no eo eu git AL Table 19 lists the comparison of the thermal neutron absorption cross section obtained from the fitted experimental thermal neutron dieaway data and the calculated macroscopic thermal neutron absorption cross section calculation spreadsheets shown in Tables 16 18 for all three configurations It is important to note that the calculated macroscopic thermal neutron absorption cross section for the layered asteroid simulant 1s based on CII carbonaceous chondrite calculations and the macroscopic thermal neutron absorption cross section was obtained from the layered asteroid fitted experimental thermal neutron dieaway data There is good agreement between the calculated and experimental 2 values Table 19 Granite basalt and asteroid simulant calculated and experimental macroscopic thermal neutron absorption comparison Note the asteroid simulant calculated value 1s based upon CTT carbonaceous chondrite calculations ya cm Homogeneous Homogeneous Layered Granite Monument Basalt Monument Asteroid Simulant 0 0114 0 0179 0 0264 Exp 0 0119 x 2 1396 0 0189 2 43 0 0246 8 09 96 C
54. 06 0vT 6TT0000 0 6 TT TO O e ep owed 994S ang wdd SW SN4 L0 340186 Z Sc 3 E 9 8T 3v8997 T vPC 3 07c8S T Z0 359 00 8 9IT OPT ZZTT000 0 uMou xun T0 30 9 T0 30 9 0 300 T ott opt T OTT OPT ZZTT000 0 Arn S0 0 exep 21u1e485 1994S AL wdd SW Snd 90 3 9290 S vc 3vT 6 LI 4668 S S vC 3 078S8 T Z0 381T0S SS06 8ET S0 d3E 98 p uMouxuf 00 3bT 6 00 3pT 6 F 200 2 SS06 8 T Z SS06 8ET S0 3 98 ELEEELED gt S0 0 exep 21u1e485 994S SAe wdd SW SN4 90 39T789 vc 3c S8T 3 T0 0 vPc 3 078S8 T 90 3290v6 1 SEET S 992000 0 uMou un 00 3071 00 307 T 0 300 Z LCE LET LEE ET 99Z000 0 S 99c eaep 21u1e485 993s ane wdd dO2I Shd 90 3SSTZT 9 SEIN LT 38801T Z vPC 3 078S T Z0 387v 1 SvSOG CET S0 3E EZZ T uMouxuf T0 306 c TO 306 c S0 300 2 SvYS06 7 T Z SbS06 ZET GO AEEELL T E EEEEEL LT ro eyep 5iue485 994S ane wdd SW SN4 80 3S2 0t T vc av s ST 3T996S 7 vPC 3 07c8S8 T 60 38S7Cv9 9Z TI7T 000000 0 uMou uf 00 30tb S 00 30t S 0 300 T 9L TZT T O9L TZT z000000 0 aasn eo DN e ep Diwesad 994S ang wdd SW snd 80 3 2969 4 Sc 3E 9 LT 3 9T77 T vPC 3 078S T 80 36174 TZ STT 90 3 999T 6 uMwouxufi T0 30 9 I0 30 9 0 300 Z TZ 8TT Z OTZ STT 90 3 9991 6 199999991 6 I e ep owe 994S ang wdd SW SN4 L0 5S0 29 Z cC 3v6 I ST 398 Z T vPC 3 07C8S T OTI dtP60 98 SIS VII T000000 0 uMou ufi cO 3v6 l Z0t3v6 T 0 300 STS VIT 8I8VTT T000000 0 aasn
55. 1 DANA filtered pdf 120228GelTLTOO1 1 inelastic filtered pdf e 120228Gel TLTOOI 2 log pdf 120228Gel TLTO0OI 2 capture filtered pdf 120228Gel TLTO0OI 2 DANA filtered pdf 120228GelTLTOO1 2 inelastic filtered pdf e 120228Gel TLTOO2 log pdf 120228Gel TLT002 capture filtered pdf 120228Gel TLTO0O02 DANA filtered pdf 120228GelTLT002 inelastic filtered pdf e 120228Gel TLTOO3 log pdf 120228Gel TLTO0O3 capture filtered pdf 120228Gel TLTOO3 DANA filtered pdf 120228GelTLT003 inelastic filtered pdf e 120301Gel TLTOOI 1 log pdf 120301 Gel TLTOOI 1 capture filtered pdf 120301 GeI TLTOOI 1 DANA filtered pdf 120301 Gel TLTO0OI 1 inelastic filtered pdf e 120301Gel TLTOOI log pdf 120301 Gel TLTOOI capture filtered pdf 120301 Gel TLTOOI DANA filtered pdf 120301 Gel TLTOOI inelastic filtered pdf e 120301Gel TLTOO3 log pdf 120301 Gel TLTOO3 capture filtered pdf 120301 Gel TLTOO3 DANA filtered pdf 120301 Gel TLT003 inelastic filtered pdf EE The available data for the 2 2 configuration 1s as follows e 120312Gel TLTOOI 1 log pdf 120312GelTLTOO1 1 capture 17 150 650us filtered pdf 120312GelTLTOO1 1 inelastic filtered pdf 120312Gel TLTOOI 2 capture 17 150 650us filtered pdf e 120312GelTLTOO1 2 log pdf 120312GelTLTOO1 2 DA NA 17 650 1 999 9us filtered pdf 120312GelTLTOO1 2 inelastic filtered pdf 120312GeTLTO001 1 DA NA 17 650 1 999 9us filtered pdf e 20313Gel TLTOOI log pdf 120313GelTLTOO1 capture 16 2 150 650us filtered
56. 1009Gel TLTOO2 DANA filtered pdf 121009Gel TLTOO2 inelastic filtered pdf 121009Gel TLTO00O3 log pdf 121009Gel TLT003 capture filtered pdf 121009Ge1TLT003 DANA filtered pdf 121009GelTLT003 inelastic filtered pdf 121010Gel1 TLTOOI log pdf 121010Gel TLTOOI capture filtered pdf 121010Gel TLTOOI DANA filtered pdf 121010Gel TLTOOI inelastic filtered pdf 121010Ge1TLT002 log pdf 121010Gel TLTO002 capture filtered pdf 121010Gel TLTOO2 DANA filtered pdf 121010Gel TLTOO2 inelastic filtered pdf 121010Gel TLTOO3 log pdf 121010Gel TLTO0O3 capture filtered pdf 121010Gel1 TLTOO3 DANA filtered pdf 121010Gel TLT003 inelastic filtered pdf 111 e 121010Gel TLTOOA log pdf 121010Ge1TLT004 capture filtered pdf 121010Ge1TLT004 DANA filtered pdf 121010Gel TLTO0OA inelastic filtered pdf e 121010Gel TLTOO5 log pdf 121010Ge1TLTOOS capture filtered pdf 121010Ge1TLT005 DANA filtered pdf 121010Ge1TLTOOS inelastic filtered pdf e 121010Gel1TLT006 log pdf 121010Gel TL TOOO6 capture filtered pdf 121010Gel1 TLTOOO DANA filtered pdf 121010Gel TLTOOO inelastic filtered pdf e 121010Gel TLTOOT7 log pdf 121010Gel TLTO0O7 capture filtered pdf 121010Ge1TLT007 DANA filtered pdf 121010Gel TLT007 inelastic filtered pdf e 121010Gel TLTOOO log pdf 121010Gel TLTO0OO9 capture filtered pdf 121010Gel1 TLTOO9 DANA filtered pdf 121010Gel1TLTOOO9 inelastic filtered pdf The thermal and epithermal neutron data is listed in the following files e 110821He
57. 10808 P 62176 08T 28000000 0 umou un TO 3IT C TO 3IT C v0 300 T 6Zv6 08T T 6zv6 08T 8000000 0 L8 0 TO O wdd SW SN4 eL EZ 90 48SE96 Z ZZ 4Z0 T 9T 58bS06 2Z bZ 4290Z9 T 80 IZ8Z6L T GESAT Z 00000 0 umouxun ZO 4Z0 T Z0 4Z0 T 20 300 Z 6v 8ZT 2 ev 8Z1 2 00000 0 ZE T O wdd SW SN4 JH eL L0 388 7 7 2 JEL L ST 388688 2 vPC 3729079 1 60 J6TE8L T Z96 v4T Z1 000000 0 uMou un TO 3EZ Z TO 3EZ Z 0 300 T L96 bLT 1 796 v41 ZT 000000 0 DG 2000 wdd SW SN4 nq TZ L0 JEETZ8 9 c 399 91 3S 98 T VC 3C9079 T 80 3200ST I vO EZT 66100000 0 uMouxun T0 399 T0 399 0 300 VO EZT O ELT 66100000 0 eet Top wdd SW SN4 qA OZ L0 31T 90 cc 3 0T ST 368 6 C VC 3C9079 1 60 3 0S 8 T TCvE6 89T T 000000 0 uMouxun 0 3 0 I ZO HE0 T S0 300 c Icvt 6 89T c TICv 6 89T 1 000000 0 Leg S00 0 wdd SW SN4 wL 69 90 39 vt SEW EELER b 579029 T 80 3 v C Tl 97491 1200000 0 uMouxun 720 4729 T 7Z0 4Z9 T Z0 400 92 491 9c 491 T200000 0 EI I0 0 wdd SW SN4 43 89 L0 31996 t DECK ST 3E849v 4 vZ 47Z90Z9 T 60 IT0809 cEO 6 v9T 94000000 0 uMouxuf TO 3S9 9 T0 4S9 9 S0 300 2 c 0 6 HOT e e 0 6 v9T 94000000 0 9ZL 0 I0 0 wdd SW Sn3 oH L9 S0 3286 8 cc 3 6 9T 3p887T v vPc 3c9079 T1 80 J369 vS8 C S CO9T vT700000 0 uMouxuf ZO A0E 6 20 30 6 0 300 S Z9T 0S Z9T 1 00000 0 bly I0 0 wdd SW SN4 Aq 99 LO 3vCC 8 T c 3S8 C ST 3TICVE Z VC 3C9079 1 60 3 v0 S v VES TE BST 4000000 0 uMouxun TO 4SS
58. 11 SOC FNG eene i RE EMI IM MEME 11 PNG Operations Manual 02 02 2011 P age 2 of 8 126 Equipment and Monument Preparations The steps to prepare the NASA GGAO Planetary Geochemistry Flight Instruments Test Site equipment and the granite or basalt monument to run experiments are as follows 1 Insure you have all the necessary equipment for your experiment The equipment you may be using includes but is not limited to the following items a Personnel equipment i Work gloves li Sun screen iii 4096 Deet bug spray to avoid getting ticks b Power cables and strips i 1 orange power cable ii 2 power strips c 2 Ethernet switches d 2red Ethernet cables located on spools inside Building 206 on the telescope platform near the stairs to the right of the door as you enter the building e 1 gray interlock cable for PNG kill switch located on a spool inside Building 206 on the telescope platform near the stairs to the right of the door as you enter the building f Lynx Digital Signal Analyzers DSAs with power cords NOTE The number of Lynx DSAs needed depends on the experiment requirements g MP320 Pulsed Neutron Generator PNG in a white box located near top of the ramp on the telescope platform Refer to the MP320 PNG Quick Start Operations Manual h Gamma ray and neutron detectors NOTE Depends on the experiment requirements i Ortec HPGe solid state gamma ray detector li LaBra gamma ray scintillation detector iii
59. 120417Gel TLTOO2 DANA filtered pdf 120417Gel TLTOO2 inelastic filtered pdf e 120418Gel TLTOOI log pdf e 20419Gel TLTOOI log pdf e 120419Gel TLTOO2 log pdf e 12042AGel TLTOOI log pdf 120424Gel TLTOOI capture filtered pdf 120424GelTLTOOI DANA filtered pdf 120424Gel TLTOOI inelastic filtered pdf e 120425Gel TLTOO2 log pdf 120425Gel TLTOO2 capture filtered pdf 120425Ge1TLT002 DANA filtered pdf 120425Gel TLT002 inelastic filtered pdf e 120425Gel TLTOO5 log pdf 120425Gel TLTOOS5 capture filtered pdf 120425GelTLTOO5 DANA filtered pdf 120425Gel TLTO00OS5 inelastic filtered pdf e 20429Gel TLTOOI log pdf e 120430Gel TLTOOI log pdf 120430Gel TLTOOI capture filtered pdf 120430GelTLTOOI DANA filtered pdf 120430Gel TLTOOI inelastic filtered pdf e 120501Gel TLTOOI 1 log pdf 120501 Gel TLTOOI 1 capture filtered pdf 120501 Gel TLTOOI 1 DANA filtered pdf 120501 Gel TLTOOI 1 inelastic filtered pdf e 120503GelTLTOOI log pdf 120503Gel TLTOOI capture filtered pdf 120503Gel TLTOOI DANA filtered pdf 120503Gel TL TOOI inelastic filtered pdf The thermal and epithermal neutron data is listed in the following files e 20419HeI TLTOOI log pdf 120419Hel TLTOO2 log pdf 120424HelTLTOOI log pdt 120425Hel TL T002 log pdf 120425HelTLT005 log pdf 120425Hel TLT007 log pdf 120429HelTLTOO1 log pdf 120429Hel TLT002 log pdf 118 e 120415He2TLTOOI log pdf 120416He2TLTOO1 log pdf 120416He2TLTOO2 log pdf 120417He2TL TOOI log p
60. 2 p Energy Scale 121102Ge1TLT001 1 DA filtered txt Equation 4353742 4542 p Energy Scale 110821Ge1TL T005 1 inelastic filtered txt Equation 0 84505 3 0542 p Energy Scale 110821Ge1TLT005 1 capture filtered txt Equation 0 7496 3 0546 p Energy Scale 110821Ge1TLT005 1 DA filtered txt Equation 0 0073299 3 0539 p 67 Gamma Ray Peak Fitting Using the Fit Gauss with Tail Igor Pro Function Each peak in the gamma ray spectra represents a unique isotope The area of the peak represents the number of gamma rays detected which is used to determine how much of that isotope is present The peaks are fitted using Igor Pro fitting tools to measure the area of each peak and minimize the reduced X and error of each peak fit To perform a peak fitting Select Fit Gauss With Tail Gamma gt Fit Gauss With Tail and select the wave to fit from the dropdown menu initially labeled Spectrum a graph should then appear Using the instructions described above the user should be able to find add and fit a peak If a user wants to add multiple peaks they can do so In order to add multiple peaks the user should place the purple markers around the edges of all of the peaks they would like to fit as opposed to just a single peak as described above Then place the circle marker on each of the peaks that are to be added and add them each individually The user may then fit the peaks to the spectrum one at a time or all at once it 1s
61. 2013 by Julia Gates Bodnarik All Rights Reserved To my amazing parents and brother Martha Andy and Michael providing me with the will strength perseverance and support to see this dissertation through to its completion and To my family friends mentors colleagues and mentees for their insight mentorship and infinite support iii ACKNOWLEDGEMENTS This work would not have been possible without the financial support of the VIDA fellowship the NASA Goddard Space Flight Center Co OP program the NASA PIDDP program the NASA IRAD program the Tennessee Space Grant and the National Science Foundation I am especially indebted to Dr Arnold Burger Dr Keivan Stassun Dr Ann Parsons Dr Jeffrey Schweitzer and Dr Jason Dworkin who have been supportive of my career goals and who have worked actively to provide me with the protected academic and professional time to pursue those goals I am grateful to everyone whom I have had the pleasure to work with during this and other related projects especially my NASA Goddard Space Flight Center Astrochemistry group members including Suzanne Nowicki Dr Jacob Trombka Dr Ann Parsons Dr Jeffrey Schweitzer Dr Min Namkung Dr Richard Starr Dr Larry Evans Dr Timothy McClanahan Dr Lucy Lim Samuel Floyd Dr Joseph Nuth Dr Jason Dworkin and all of the interns I worked with and mentored including Jessica Marbourgh Dan Burger Robert Forsythe Amber Keske Robert Jenkins and Rose Pe
62. 4 S8100000 0 S8 T wdd sy EE 90 36 0t T vc 3 e c LT 3CP OT 9 Vtc 3V6CvE T 0 3E8vVS V T9 ZL 0000 0 uMouxun 00 30 Z 00 30 Z Z0 400 Z I9 zZ TITL 0000 0 EE wdd 95 ZE L0 566ELb S vc 36 c LT 38S288 T Vvc 3v6cvEe T 0 39SS0p T C 69 8600000 0 uMouxun 00 306 Z 00 306 c 0 300 T 24 69 tT EZZ 69 8600000 0 8 6 wdd EE e5 TE 90 368 c8 C vpc 3Tr T 8T 3LTZ9S Z Vtc 3V6CvE T 90 JT9TT6 T 6 S9 ScT000 0 uMou xur 00 30T T 00 30T T c0 300 c 6 S9 c e s9 ScT000 0 ScT wdd uz oe S0 318pv0 t vc 367 6T 3 7 90 T VC 3V6cvE T 90 37v6 4 oke Ca S0S000 0 uMouxun 00 367 00 36Z 0 300 9vS 9 9vs 9 S0S000 0 SOS wdd no 6z 696v TT1T00 0 vyc 3 v v 0 3989TS 2 b7t dv67ve T STPZ9TOO0O 69 8S TTO O uMwou xur 00 3E v t 00 3E v v v0 300 2 v 69 8S c v 69 88 TTO O TT IM ges IN 8c S808ct000 0 EZ IZL E 6T 34Z0ST T Vc 3v6cvE T 90 3Z069S 8 ZEE6 8S S0S000 0 uwouxun TO 4ZL TO IZZ E 90 300 6 c 6 8S 6 00ZEE6 8S S0S000 0 S0S wdd SE 05 Lc bZTZTZ000 0 vc 3r 6T 3EE vV8 9 VC dV6cvE T S0 dveS960 8 1966 TS S9c00 0 uMouxun 00 30T 00 30T V0 300 9 T966 TS 9 1966 TS S9700 0 0S9z wdd Dei vc 90 3t940 4 vpc 3v0 S 8T 3 66bv T vCt3v6cvE T 90 3796 0 T1 STt6 0S SS0000 0 uMwouxun 00 3v0 S 00 370 S v0 300 T STv6 0S 1 STv6 0S SS0000 0 SS wdd A EZ cT 3TEZCV Lc 3 6 PIT3VESCL E Vtc 3v6cvE T OT AZOpZZ 78T7TO 6 60 3s 7 uMou xun 0 307 6 0 307 6 90 3
63. 4T Z0000000 0 uMouxun TO 3 EZ Z T0 3E Z Z 0 300 T L96 VT 1 796 vZ41 S20000000 0 Sz0 0 wdd RE m TL 80 3SZvvS v c 399 ST 3vALTVC T vc 3v6cvE T OT HCU9vC 6 vO EZT 91000000 0 uMou xurn TO H99 T0 399 0 300 vO EZT v0 ZT 91000000 0 09L 0 wdd qA 0Z 80 3669t0 c cc 3 0 1 vI 3 EL86 T Vc 3V6cvE T OT H86 V T TICVE6 89T Sc0000000 0 uMwouxun 0 3 0 T ZO 5 0 T G0 300 Z Icv 6 891 Z TZvE6 BOT S20000000 0 SZ0 0 wdd x uL 69 L0 3 TT80 C Z 4z9 T ST 3S9v87 T VC 3v6CvE T OT 4S6S9S 6 97791 91000000 0 uMou xurn c0 3c9 T ZO 47Z9 T 0 300 9Z L9T 9c 491 91000000 0 0910 wdd 13 89 80 JSZZE0 E EZ 3S9 9 tT 34L6SS v Vc 3V6CcvE T OT JLES6E E ZEOE6 YOT 9s0000000 0 uMouxun T0 3Ss9 9 I0 3Ss9 9 S0 300 Z ZEOES tat c e 0 6 tat 98 0000000 0 9900 wdd OH L9 90 3 VTZ76 T cC 3E 6 ST 390990 7 VC 3v6CvVE T 60 A9P8ES T S Z9T S2000000 0 uMouxun 2 0 30 6 20 30 6 0 300 S z9T 0s c9T SC000000 0 Sc O0 wdd ges Ad 99 60 389724 6 4 EZ JSS Z vpI 3VS97T E Vc 3V6cvE T OT HvTSCE C PES ZB BST ZE0000000 0 umouxun TO JSS Z TO JSS Z S0 300 2 VESC6 8ST Z vESZ6 8ST Z 0000000 0 L 0 O wdd qL S9 S0 3p 69 8 0z 36 b ST 3 0807 T VC 3V6cvE T 60 J98TZZ T SC ZST 000000 0 uMou xurn v0 306 t v0 306 v 0 300 Ern E SZ LST z000000 0 z o wdd SC po v9 90 AZTLTE Z Tc 39 p vI 3ICLEO S VC 3v6cvE T OT 36808 7 v96 IST ZS0000000 0 uMouxun 0 309 v 0 309 v 0 300 T b96 TST T p96 TST ZS0
64. 729079 1 OT AZS8TT E 990 7 10000000 0 uMouxun I0 307 S I0 307 s 0 300 9 990 7 9 990 2 T0000000 0 aasn to o gt TO O IM WI S 9T L0 39Tv9 T LC 3LE 6T 43v6ZV0 b vPc 379079 1 S0 37446V 0 ZOTO ZT 000 0 uMouxuf 0 3 0 3 V0 300 8 LOTO ZT 8 40TO ZT 000 0 0 0 Top 9 93M WI je301 5 2 9 80 36017 GEN ST 37TC06 b VPC 3Cc9079 1 60 3 8v70 T6870 8EC 4000000 0 uMouxun 00 3484 00 3484 S0 300 T68ZO 8EZ T68Z0 8E7 Z4000000 0 ZC0 Top wdd SW SN4 n c6 60 38Tvp8S 7 vC 3v L vPTI43PIC6VP Z IZ90Z9 T OT IZ8HST Z T8 0 CEC S0000000 0 uMouxun 00 30t Z 00 30t Z t0 300 T I8E0 CEC T T8EO ZEZ 0000000 0 so o S0 0 wdd SW SN4 uL 06 IT 3ITI6SS 7 9z 3 vTI 368vS Z vc 3c9079 1 OI dPTISSZ v X 8 086 80c 10000000 uMwouxuf 0 30 0 30 S0 300 2 8 086 80Z e 8 086 80c 10000000 aasn r o T O wdd SW SN4 Ig 8 60 3 8v9 9 Sz 3 1 91 39Z 0T6 bZ 4Z90Z9 T 80 JgETETV C C Z0Z S00000 0 uMouxuf I0 307T I0 307 T I0 300T coc T Z ZOZ S00000 0 qasn s S wdd SW Sn4 qd ze 60 386 v T vc dv VTI 399v96 bZ 54Z90Z9 T 0OI d8t9vPv C EESE vOC S0000000 0 uMouxur 00 30t 00 30t v0 300 c ELBE HOT c EE8E vOC S0000000 0 aasn so o gt so o wdd SW Sn4 LL T8 80 3ECvVST 8 c 3S8 T ST 369Z0t v bZ 47Z90Z9 T 60 A9Z6TL BEST S000000 0 uMouxur TO 4S8 T T0 4S8 T Z0 400 T v8 8T T v8 8T S000000 0 qasn s o S O wdd SW SN4 M vL LO 3Tbv9 T c 3IT c ST 39616 Z bZ 47Z90Z9 T 60 3
65. 8 6T7 T VC 3Cc9079 1 OI JSTPZS SvSOG CET T000000 0 uMouxur T0 306 c T0 306 c S0 300 2 SySO6 CET c SvSO6 CET 1000000 0 aasn r o T O wdd SW SN4 S2 SG 80 3Zv V T vc 3v S ST 366199 C VC 3C907c9 T 60 38SCv9 l ZT ZT 20000000 uMouxun 00 30t S 00 30t S 0 300 T 9 T7T T O9Z TZT z000000 0 aasn z o gt co wdd SW SN4 qs TS 60 317009 8 Sc 3E 9 9T 361S9 T F r concot 60 368 CV 8 TZ 8TT T00000 0 uMouxun I0 30 9 I0 30 9 0 300 7 IZ81I Z 0TZ 81I 100000 0 I I wdd SW SN4 us Oe L0 3Sc8 7 7Z 4v6 T GT 3LbT bt vZ 5790Z9 T Oot tbten g ST 8 VII T000000 0 uMouxun Z0 3v6 I Z0 3v6 T 0 300 8T8 VTT 8T8 PTT 1000000 0 aasn r o T O wdd SW Sn4 ul 6v L0 3S0668 9 EZ J9S 9 9T 369TS0 T VC 3729079 1 60 3v68V 9 7898 LOT 000000 0 uMouxur T0 39S 9 T0 395 9 v0 300 2 c898 Z0T Z Z898 ZOT 000000 0 LO S O wdd SW sn4 5v Ly 80 4Z27S6 8 vc 3s9 c 9I 3v8 E VPC 3C79079 1 980 3v9v80 0 v6 S6 Z00000 0 uMouxur 00 4S9 Z 00 4S9 Z 20 3001 v6 S6 I1 v6 S6 200000 0 qasn z gt c wdd SW SN4 oW ev L0 39v06v E LT 38TS 0 bZ 479079 T LO AS8ZZ8 T 8E906 Z6 vLT0000 0 uMouxur 00 4ST T 00 3ST T S0 300 2 8 906 26 c 8 906 76 vL10000 0 vL co wdd SW SN4 qN Ty L0 3SCvCE S Sc 3S8 T 81T 3 6 48 C bZ 5790Z9 T 90 358S 7 T vec T6 Z9T000 0 umou un TO 4S8 T TO 4S8 T 0 300 2 vec T6 2vec l6 Z9T000 0 ZOT T wdd SW SN4 JZ Ov ZO ASTEZ6 D vc 38c T DREMS bZ 3790Z9 T Z0 3EE E C S8S06 88 TTZ0000 0 umou yun 00 387 I 00 387 T S0 300 Z S8S06 88 Z S
66. 8S06 88 TTZ0000 0 TIZ S O wdd SW SN4 A 6 S0 3 6926 T SEVEN 6T 3TSZ6S T b 47z90Z9 T 90 IZS9Z8 6 Z948 T98000 0 uMouxuf O0 3IZ T O0 3IC T 20 3001 c9 78 1 29 28 1980000 T98 wdd dOI Shd JS 8 80 4S8ST0 Z SC 3L LT 381968 T VC 3C907c9 T 40 3 007T I 849t S8 T0000 0 umouxun I0 307 I0 30Z7 v0 300 8 9v S8 849v s8 T0000 0 OT T wdd SW SN4 qu LE 20 49059 r vc 3 LT 3VSTS0 T b7 579079 T 80 d 9 9 9 9I76 vZ S00000 0 uMouxun 00 30 t 00 30 t S0 300 c EIN c 091c6 v4 00000 0 aasn s S wdd Sw sn4 sy EE 80 3 S 9 9 vec 3 c 9T 3PST06 C tc 3c9079 1 80 36 06 T T9 74 T00000 0 uMouxun 00 30 c 00 30 2 0 300 c TZL e 100000 0 T S O wdd SW SN4 95 ZE 90 IZEETZ T tz 36 Z LT 398 8T b vZ 5790Z9 T Z40 3v9188 7 74 69 8T0000 0 uMouxun 00 306 2 00 306 2 0 400 T 22 69 T EZZ 69 810000 0 8T I wdd SW SN4 eS TE 90 JEZ9ZL Z ve 3rT 8T 36 8 V C Vc 379079 1 90 J6Z6ZS T 6 S9 I000 0 uMouxur 00 30T T 00 30T T Z0 300 Z 6 S9 Ziler eg I000 0 oot oE wdd Sw sn4 uz oE 90 34689 9 vc 364L 8T 37CS8 T bZ 579079 T 90 39STOT T 9bS E9 0000 0 uMouxur 00 367 00 367 0 300 9pS 9 9vS o 0000 0 0Z OT wdd SW SN4 no 6c S0 36Z7v 8 T EISCHT S8T43PZTVT b v 4z90Z9 T 90 JS9SSS Z7 v 69 88 ST000 0 umou un 00 3Et t 00 3E t t v0 300 2 v 69 8S c v 69 8s STO00 0 OST oc wdd SW SN4 IN 8z S0 36Tv6T b c 37 ST43ZvVZ 7T T Z 3Z9079 T 40 3 0786 9 ZErege Tv0000 0 uMouxun TO 37 E T
67. 987 0 127624 Width Free 2 6411 298 0 051299 gauss 4 3978 True FWIM 8 0155 Junction Fixed 100 Peak 2 Gauss Tail area 24365 9242 177530549 228 Amplitude Free 64243 0168 1 14051e 11 Centroid Free 1778B 71457 380252 Figure 40 a Right A triple peak fit with an appropriate baseline b Left Zoomed in view of the Igor peak fitting report outlined in red showing that the Peak 2 area fit outlined in aqua blue has a large error and requires adjustments to improve the Dis accuracy 69 Neutron Data Analysis The work presented in these next two sections is from J G Bodnarik J S Schweitzer A M Parsons L G Evans and R D Starr PING Gamma Ray and Neutron Measurements of a Meter Scale Carbonaceous Asteroid Analog Material 43 Lunar and Planetary Science Conference No 1544 2012 The epithermal and thermal neutron dieaway data can be analyzed to determine the H content and macroscopic thermal neutron absorption cross section of the bulk material The H content was not determined from the epithermal neutron experimental and MCNPX data due to time constraints but it will be determined and presented in a publication in the foreseeable future We experimentally tested and verified the absorption properties of the granite monument the basalt monument and basalt layering asteroid simulant neutron properties analogous to a CII carbonaceous chondrite meteor
68. 999TES 0 TO O e ep 5iueJ82 994S ang wdd SW SN4 90 39 18 t zc 3 E 6 ST 3609 T S VPC 3 078S T 60 36 17C S COT L0 3499T1 S uwouxun c0 30t 6 0 30 6 0 300 SG zort 0S Z9T 0 00000 0 ZO E TO O ep 21619 ae3s aAe wdd SW SN4 L0 310999 7 EZ 3SS C 91 38c900 VC 3 0c8S T 80 392006 1 v SC6 8SI Z0 00000 0 umouxuy TO JSS Z TO JSS Z s0 300 Z VESC6 8ST c v S76 8ST LO 3 E8V 9 E E EEESV9 O TO O e ep 21u1e482 Jae3s ane wdd SW SN4 6096T1 000 0 07 36 v ST 3Vp97CS 9 vPC 3 078S 1 60 3S6CCT v SC ZSI L0 J3 ESp 9 umouxun V0 306 v v0 306 t c0 300 Sc ZST E SZ LST SSv00000 0 ossy I0 0 exep 2iure485 994S eAe wdd SW SN4 S0 JpTZ69 Z Tc 39 v ST 38v7S8 S VPC 3 078S T 60 AVE669 E v96 IST Z0 4Z9T79 uwouxun 0 309 v 0 509 b 0 300 T v96 IST TI r96 IST L0 3491c9 S 1999912980 S00 0 eep 2iuIe485 394S SAe wdd SW Snd LS8TEVOO0 0 Tc 38 s 9T 3T8Sbv vPC 3 0788 T 80 38590 v0 Y9E OST 90 3 99 0 7 uwouxun 0 308 S 0 308 S c0 300 oC oer g oe osT 90 3499 0 Z 1999999704 TO O e ep D1wWeisd 394S SAe wdd SW SN4 S0 3 6 0 Z 2 3S0 S LT 3808 0 t vC 3 078S8 T Z0 39vCSS 7 vecvVI S0 3 9189 UMouxun TO 3S0 S TO 3S0 S 20 300 veCvvT Eve vv S0 3 9189 19999918 9 so o e ep olweJad 9974S AL wdd SW SN4 90 38v9 S T Z 3ST T LT 3409 T vC 3 078S8 T 80 3S7Svp 8 S9 06 0vT 6110000 0 uMouxun TO SST T TO SST T S0 300 2 S89 06 0vT 2 594
69. Basalt Monument Columbia River Basalt PING Experimental Configuration Figure 48 shows an image of the PING instrument set up on top of the Columbia River Basalt monument The PNG is on the left hand side of the basalt monument followed by the epithermal and thermal He 3 neutron detectors in the center and the HPGe detector on the righthand side of the basalt Figure 49 is a schematic of the dimensions of the Columbia River basalt monument Figure 50 is a sketch of the dimensions distance and spacing of the PING components from one another and Figure 51 are additional notes taken during the experiment 120 Figure 48 Image of the PING instrument prototype on top of the Columbia River Basalt monuement taken on 08 21 2012 1 83 m 0 61 0 61 m 0 61 d 0 61 Figure 49 Schematic of the Columbia River Basalt monument dimensions 121 E 18 25 Sa AA p GE SE amo 7 RBIS E DEE vado Lo tele ez E be pua Sift in Zu FL Tool 007 e Feel sie ag emi SCH WEE k Pemo pods Byles Vu 7 SBE ren Sem kzal Y ORAZ shou n dia ik SEO pr Zo 2 APP HA Por WM Lo loce Figure 51 Notes from the basalt monument PING experiment 122 Asteroid Simulant Asteroid Simulant PING Experimental Configuration Figure 52 shows a picture of the PING instrument set up on top of the asteroid simulant The PNG is on the left hand side of the configuration followed by the epithermal and therm
70. E lO Serera E E sed oe dex PR pes duse 34 Lynx DSA electronics and acquisition software 36 III DATA ANALYSIS AND MCNPX CALCULATIONS eerte 39 EX EE EE EE 39 Gamma ray data analysis ciet i Idae etel input oreet chat buUo does sede tubi bu pu ad besepeius sius 40 The TLIST data acquisition techmoue eeeesseeoeeeesssssssoeeeesssssssserresssssseees 40 TLIST dat analysis tec nique iov i deat PO to dle 42 Improved gamma ray measurement precision eesssssssseeterrssssssseererssss 46 Identifying and removing sources of systematic error using TLIST data 50 Energy calibrating spectra using Igor Pro 6 2 software 53 Putting energy calibrated spectra on one energy scale using Igor Pro 6 2 66 Gamma ray peak fitting using the fit gauss with tail Igor Pro function 68 Neutron EE 70 MCNPX Gata analysis aset eege eege neun dip Fate ep dus 72 Geometry amd VISE D uites ptu ud Lem a MM LER e Le 73 Configurations modeled and approximations that were made 73 ENEE zma Ee 75 IV RESULTSANDINTERPRETA HON 5 it ett ito e i EI ttt eens 76 Results and IntetpretattOD us eege ees 11 OSAMA EE d PNG COUT ee 90 Ve EL E 97 REFERENCES EE 100 JAPPENDIS Fece ene mere een Oe meen err ane earn een ene ne ee eee er oe eee ee ee 105 va ale bib D dA E tc LN 107 usu SPIRI E 124 vii LIST OF TABLES TABEE
71. G components on top of the basalt layering asteroid simulant The basalt layering asteroid simulant material selection and construction was based on MCNPX 60 computer modeling results and ACTLabs independent elemental assay information MCNPX modeling was used to compare the neutron spatial distribution of a homogenous C type asteroid and basalt layering asteroid simulant to insure that the simulant and C type asteroid had similar neutron moderation properties To insure that the neutron response for the basalt sample is like that of a C type asteroid the key elements are that the thermal and epithermal neutron fluxes as a function of depth beneath the surface need to closely approximate those of a C type asteroid Figure 9 shows the MCNPX modeling results for the epithermal and thermal neutron fluxes as a function of depth beneath the surface for both a C type asteroid and the basalt layering asteroid simulant The basalt layering asteroid simulant model is in good agreement with the C type asteroid CI1 Ivuna like carbonaceous chondrite composition model The basalt layering asteroid simulant clearly mimics the neutron flux 25 distribution for the C type asteroid composition especially since the majority of the eamma rays produced through nuclear interaction processes will be coming from the surface down to 30 to 35 cm The fluctuations in position of the data points for the basalt layering simulant are due to the fact that the simulant is l
72. Gamma Ray Data Acquisition for In Situ Subsurface Geochemistry Nucl Inst and Methods in Phys Research A v 707 p 135 142 PING gamma ray and neutron data are acquired using custom software to control the digital signal analyzer electronics and synchronize time tagged event by event data acquisition with the start of each PNG burst These data coupled with MCNPX 55 computer simulations allow us to quantitatively determine the bulk elemental composition of the subsurface material for any solid body in the solar system The MCNPX calculations allow a statistical calculation of both the energy and the time of a gamma ray event detected in a detector The calculations take into account the primary factors involved in neutron production and transport and track most of the nuclear reactions on all elements present in the material many of the gamma rays that can be produced as well as their transport and detection at a specific point in space by a particular detector Thus the Monte Carlo calculations provide a direct relationship 39 between peak counts and elemental concentrations limited only by the count rate uncertainty and the calculation uncertainties generally less than 1 Gamma Ray Data Analysis The TLIST Data Acquisition Technique 66 Analyzing individual gamma ray peaks in a traditional PHA energy spectrum can be challenging due to both interfering lines and the background continuum resulting from multiple processes We redu
73. HAPTER V CONCLUSIONS Asteroids are the remains of the formation of the Solar System They provide us with a glimpse into the past and insight into how our solar system formed evolved and how life may have begun Unfortunately there is still a lot we do not understand about asteroids including which meteorites belong to which asteroid classes and types and what asteroid bulk geochemistry traits differentiate one type from another In order to find the answers to what we don t know about asteroids we must collect information on a wide variety of wavelengths and spatial resolutions One way to determine the bulk elemental composition of asteroids is through the development and testing of the Probing In situ with Neutrons and Gamma rays PING instrument on well characterized granite basalt and asteroid simulant monuments The asteroid simulant monument was designed with the help of a Monte Carlo model to have the same bulk elemental concentration as a typical CI1 asteroid and to have the same neutron response as a homogeneous asteroid The latter criterion ensures that experimental measurements on the asteroid simulant monument will have the same relationship between gamma ray peak count rates and elemental concentrations as would occur for measurements on the surface of a homogeneous asteroid The monuments are located at a unique facility implemented at Goddard Space Flight Center PING utilizes fast neutrons generated by a 14 MeV pulsed neutr
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76. P v0 3 MON Du Connect SHV HV here for HPGe detector 12V DC Power Connector Lynx does NOT have a ON OFF switch it is ON when the Computer Ethernet connector Connect the yellow power is plugged Ethernet cable from here to the Ethernet switch in and OFF when connected to the computer it is unplugged Connect the HV Connect the Inhibit Connect the preamplifier Shutdown HPGe HPGe detector cable power here using a cable Detector cable here to the TRP with a 9 pin D connector here to the HV Inhibit connector Inhibit connector Figure 7 Important Lynx DSA rear panel connectors for the HPGe detector ii Locate the 9 pin D connector the HV SHV connector the Output 1 BNC connector the HV Shutdown BNC connector and the Inhibit BNC connector on the HPGe detector iii Connect the HPGe detector preamplifier power Connect the HPGe 9 pin D connector cable to the grey 9 pin D extension cable Connect the grey 9 pin D extension cable to the Lynx s PREAMP connector iv Connect the HPGe detector negative HV power Attach a SHV extension cable to the HPGe HV SHV connector Connect the other end of the SHV extension cable to the Lynx HV connector v Connect the HPGE Output 1 HV Shutdown and the Inhibit BNC connectors to Lynx 1 Connect a skinny BNC extension cable to HPGe Output 1 BNC connector and connect the other end of the extension cable to the Energy connector on Lynx 2 Connect a skinny BNC exten
77. PHYSICS USING IN SITU NEUTRON AND GAMMA RAY SPECTROSCOPY TO CHARACTERIZE ASTEROIDS JULIA GATES BODNARIK Dissertation under the direction of Professor Keivan G Stassun and Dr Ann M Parsons Asteroids are remnants of the formation of the Solar System and provide insight into its formation evolution and how life may have begun An important issue is determining which meteorite composition is representative of which asteroid class and type n situ composition measurements would be one way to resolve this issue This dissertation contributes toward developing and testing of a neutron gamma ray spaceflight instrument for subsurface regolith composition measurements for landed asteroid missions The Probing n situ with Neutrons and Gamma rays PING instrument was tested at an outdoor test facility on well characterized granite basalt and asteroid simulant monuments with a variety of different layering configurations PING utilizes a 14 MeV pulsed neutron generator to probe the subsurface and uses neutron and gamma ray spectrometers to detect the resulting moderated neutrons and gamma rays The neutron and gamma ray energy spectra are used to determine bulk properties and the material composition We compared our experimental spectra both to Monte Carlo simulations and to independently verified elemental assays in order to establish a benchmarked Monte Carlo model This comparison shows that PING can quantitatively determine bulk asteroid
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79. Solar System and strengthening and studying the meteorite to asteroid composition connection would then lead to understanding of the elements and materials present during the formation of the Solar System What Techniques Have Been Used Most of the research concerning the geochemistry of C complex asteroids has been limited to either laboratory meteorite analog analysis or in situ and space based remote sensing using VIS NIR IR X ray XRS and gamma ray spectroscopy GRS 18 19 VIS NIR IR and XRS measurements only probe a few microns to a few millimeters deep to reveal the surface geochemistry of an asteroid However space weather processes Figure 2 as verified by laboratory measurements significantly alter the chemistry of the surface materials so that they are not representative of the bulk material In addition laboratory geochemistry composition measurements of small scale C complex meteorite analogs may not be representative of the overall bulk composition of C complex asteroids as seen from analysis of the Almahata Sitta meteorites 1 Passive remote sensing orbital GRS and or neutron spectroscopy NS measurements can be used to probe the subsurface of asteroids to tens of centimeters below the surface and can yield information such as the overall bulk geochemistry and presence of hydrogen However orbital gamma ray and neutron instruments depend on the Galactic Cosmic Ray GCR particle flux as the excitation source an
80. TLTO00O3 log pdf 120307Gel TLTO00O3 capture 17 1 150 650us filtered pdf 120307Gel TLT003 DANA 17 1 650 1 999 9us filtered pdf 120307Gel TLTOO3 inelastic filtered pdf 120309Gel TLTO00I 1 log pdf 120309Gel TLTOO1 1 capture 15 9 150 650us filtered pdf 120309Gel TLT001 1 DANA 15 9 650 1 999 9us filtered pdf 120309Gel TLTOOI 1 inelastic filtered pdf 120309GelTLT002 1 log pdf 120309Gel TLT002 1 capture 17 2 150 650us filtered pdf 120309Gel TLT002 1 DANA 17 2 650 1 999 9us filtered pdf 120309Gel TLTO00O2 1 inelastic filtered pdf 120309GelTLT002 2 log pdf 120309Gel TLT002 2 capture 17 1 150 650us filtered pdf 120309Gel TLT002 2 DANA 17 1 650 1 999 9us filtered pdf 120309Gel TLTO002 2 1nelastic filtered pdf 120309Gel TLTO00O3 log pdf 120309Gel TLT003 capture 17 6 150 650us filtered pdf 120309Gel TLT003 DANA 17 6 650 1 999 9us filtered pdf 120309Gel TLT00O3 inelastic filtered pdf 120305LB1TLTOO1 log pdf 120305LBITLTO0O3 log pdf 120305LBITLTOOS5 log pdf The thermal and epithermal neutron data is listed in the following files 120305Hel1TLTO002 log pdt 120305Hel TLT003 log pdf 120305Hel TL TOO6 log pdf 117 Ice 1 The available data for the Ice 1 configuration 1s as follows e 120416Gel TLTOOI log pdf e 120417Gel TLTOOI log pdf 120417Gel TL TOOI capture filtered pdf 120417Gel TLTOOI DANA filtered pdf 120417Gel TLTO0OI inelastic filtered pdf e 1 20417Gel TLTOO2 log pdf 120417Gel TLTO0O2 capture filtered pdf
81. actor of 2 5 and this difference is most likely due to the lack of Al in the model as mentioned in the discussion about Table 13 The lower value of the MCNPX Na Si ratio could be explained by the distance and location of the PNG and HPGe detector on the basalt monument as mention in the Table 13 Both O Si experimental and MCNPX ratios are in fairly good agreement with one another and differ on average by a factor approximately 0 9 However Fe Si experimental and MCNPX ratios are in very poor agreement with each other and differ by a factor of 82 The poor agreement can be due to the fact that the experimental ratios take into account everything in the experiment while the MCNPX model was constructed with only a point source for the PNG and a HPGe crystal for the HPGe detector at approximately the correct distance and location from the PNG As previously discussed the model didn t include the HPGe detector housing and dewar the PNG housing or either of the neutron detectors and the locations of the detectors and PNG were at the same approximate locations as on the granite monument The absence of these pieces of equipment could explain the low value of the Fe Si ratios since the PNG and HPGe housing and dewar contained a great deal of Al and some steel which contains Fe As seen in Table 15 for the PING asteroid simulant experiment the Na Si experimental isotopic ratio and uncertainty is 0 176 5 97 as compared to the MCNPX ratio and uncertaint
82. al Composition Topics in Remote Sensing 4 Carle M Pieters and Peter A J Englert Eds Cambridge University Press 59 Bodnarik J G et al PING Gamma Ray and Neutron Measurements of a Meter Scale Carbonaceous Asteroid Analog Material 43 Lunar and Planetary Science Conference No 1544 2012 60 D B Pelowitz et al 2005 MNCPX User s Manual Version 2 5 0 LANL Los Alamos LA UR 05 0369 61 A M Parsons personal communication 2009 62 Knoll G G 1999 Radiation Detection and Measurement 3 edition Wiley p 365 63 Knoll G G 1999 Radiation Detection and Measurement 3 edition Wiley p 508 64 CANBERRA Lynx Digital Signal Analyzer application note 2012 http www canberra com literature 438222 asp 65 D Burger personal communication 2011 66 J Bodnarik et al 2013 Time Resolved Neutron Gamma Ray Data Acquisition for In Situ Subsurface Geochemistry Nucl Inst and Methods in Phys Research A v 707 p 135 142 67 R J Radtke et al SPWLA 53rd Annual Logging Symposium Cartagena Columbia June 16 20 2012 68 Thermo Scientific MP320 Neutron Generator Operation Manual 69 Knoll G G 1999 Radiation Detection and Measurement 3 edition Wiley p 56 70 Randy A Schwarz Visual Editor Consultants www mcnpvised com 104 APPENDIX I ACTIVATION LABORATORIES LTD ELEMENTAL ASSAYS Concord Grey Granite Assay Activation Laboratories Granite Assay R
83. al He 3 neutron detectors in the center and the HPGe detector on the right hand side of the simulant See Figure 50 for PING dimensions and spacing PNG He3Th n detector HPGe y ray detector He Epi n detector d e CT T Dm um NV basalt amp poly layering ZS 1 8 m x 1 8 m x o 9 m Columbia River Basalt Monument gout Figure 52 Image of the PING instrument on the layered asteroid simulant 123 APPENDIX III PING EXPERIMENT OPERATIONS MANUALS The following two manuals explain the basic experimental operations for conducting PING experiments at the GGAO test facility 124 Julia G Bodnarik NASA Goddard Space Flight Center Code 691 02 04 2011 125 Table of Contents Equipment and Monument Preparations ceeeeeneeseeeeeeseeeneeseenneese nnns 3 Necessary Experiment Eoupment sse nennen nennen 3 Uncover the Monument oca onore tennessee a iai E iaaiaee Ke Take Equipment to the Monument 3 Setup the Power Communication and PNG Interlock Cables 4 Equipment Setup for PNG Experiments eee eceeeeeee nee ee nennen nnns 4 Open the PING GU BEN 8 Set the Beam Current and HV ccccccccccccceeesessee ceeeeeeeeeseeeeeceeeeseseeeseee reset naar nnn nnns 9 Setup the bulser nnn eeceeseseeeaeeceeeeeeseeesaees eeseesaeeaes 9 ETIN NR ETE TE 10 elle Me PNG T H
84. all grass on July 28 2008 We remotely operate PING on known samples minimizing background signals from neutron and gamma ray interactions with nearby structures shown in Figure 7 The facility is equipped with an operations building that provides power and communications to the monuments so users can operate and monitor their systems at a safe distance from the PNG The radiation safety perimeter is visually monitored during operation and a video and motion sensor surveillance system will be installed in the near future 22 Figure 7 Image of the test facility with the operations building left the basalt monument covered with the homogenous C type asteroid layering simulant right and eranite monument far right A unique feature of our test facility 1s the ability to perform layering studies using granite basalt and polyethylene tiles with dimensions of 0 31 x 0 31 x 0 013 meters 0 31 x 0 31 x 0 025 meters and 0 31 x 0 31 x 0 051 meters to simulate layers of water ice These materials can be stacked to simulate a variety of layering scenarios such as simulating the side of a crater or a homogenous C type asteroid In addition we can introduce other materials to test sensitivities of numerous elements Our large quantity of eranite basalt and polyethylene tiles and the ability to use various other layering materials affords us great flexibility in constructing numerous configurations to simulate a wide variety of pl
85. ally changed This will also allow you to set the Pls 1 Delay and Width and the Pls 2 Delay and Width for the logic pulses from SOURCE and Pulse Delay 1 connectors on the PNG electronics enclosure that you will use when taking PHA coincidence data acquisitions with Lynx PNG Operations Manual 02 02 2011 Page 9 of 11 141 f e Screen About Beam Current A 615 High Voltage kV 125 Getter Current A 2 41 PULSER SETUP External Input Frequency 10000 Hz Pls Delay 5 00 us Duty Factor 15 00 Pisi Width 10 00 Pis2 Delay 20 00 PIs2 Width 40 00 Standby Pis3 Delay 10 00 us A Ze ML 1 Mode PIs3 Width 5 00 BS Exit without Save SCIENTIFIC Pulses 518414 Figure 11 Pulser Setup Window 4 Start the PNG a Toggle the Neutron labeled software switch from the OFF position to the ON position b In the ON position the system will turn on the Lamp apply the high voltage and bring up the beam current by applying more current to the reservoir C You can monitor the progress of the PNG startup by looking at the beam current high voltage and getter current values in their current value display boxes and their graphs on the main GUI display The startup should look like the screen shot in Figure 12 E3 DNC z fn xi F e Screen About Beam Current LA 38 8 High Voltage KV 75 Getter Current A 2 43 500 DU 100 va tm
86. anetary surfaces geological features and environments Design of Physical Rock Configurations The work presented in these next two sections is from J G Bodnarik J S Schweitzer A M Parsons L G Evans and R D Starr PING Gamma Ray and Neutron Measurements of a Meter Scale Carbonaceous Asteroid Analog Material 43 Lunar and Planetary Science Conference No 1544 2012 The two meter sized structures at the test 23 facility are constructed out of Concord Grey Granite from the Swenson Granite quarry in Concord N H and Columbia River Basalt from the Corbett Station Quarry in Corbett Oregon These materials were chosen for various reasons including the ability to acquire more of the same exact material directly from each quarry for additional layering configurations and the ability for others to reproduce the experiments with known well characterized materials The granite structure was selected due to its uniform elemental composition its density and the ability to control water content outdoors due to its low porosity The basalt structure was selected due to its uniform elemental composition that was analogous to planetary bodies like Mars as well as its density and low porosity A sample of each monument was sent to ActLabs in Ontario Canada for a detailed independent elemental assay measured to ppb levels with the results in Appendix I In addition the size and placement of the structures in an open field was selected t
87. asurement confirmation and require deeper sensing techniques to discern the bulk nature of these asteroids Given our limited understanding of asteroids there 1s much that we need to know about them We still need to understand asteroid orbits the difference between the space weathered surface and pristine subsurface chemistry of asteroids the pristine organic and inorganic composition and distribution of asteroids on an atomic and molecular level and the internal structure density and porosity of asteroids that tells us about their impact and accretion history In particular making in situ bulk surface and subsurface elemental composition and water ice depth measurements would solidify the connection between C complex asteroids to carbonaceous chondrite meteorites leading to a greater understanding of how the planets were formed ASTEROID TAXONOMIC CLASSIFICATIONS E ECH RA HE TS SW eee t C Slight bluish to slight reddish slope 0 03 0 10 Hydrated minerals e Shallow to deep absorption blueward of 0 5 um Silicates C B F G zeg Hydrated asteroids with absorption at 0 7 and 3 0 um Organics Slightly reddish spectrum E 0 18 0 40 E Enstatite rich E absorption features at 0 5 and 0 6 um M 0 10 0 18 M metallic Nickel lron Blue Red P 0 03 0 10 P Carbonaceous Organics S Moderately steep red slope A lt 0 7 uim 0 10 0 22 Stony composition JI Shallow to deep absorption at 1 0 and 2 0 uim Magnesium Iron silic
88. at the user s discretion If at any point the user needs to ignore a section of the graph in order to more accurately fit a peak or for any other reason they can drag the two cursors the circle and square from the bottom left section of the graph to the section s that they would like to 1gnore Circle marks the beginning square marks the end Then moving back to the tailfit panel window click Add under Baseline Fit Exclusions To remove exclusions simply select the exclusion in question and click Remove For a more detailed view of multiple peak inclusion and baseline inclusion see Figures 4 and 5 68 below for visual examples In order to add fit and analyze peaks see the section entitled Energy Calibrating Spectra Using Igor Pro 6 2 Software for more detail EE Igor Pro 6 22A File Edit Data Analysis Macros Windows Graph Misc Help GizmoZoom Gamma TelemetryFiles Engineering Image Models MESSENGER Mapping t amp E tailfit panel 5 tailfi 3 Spectrum s ine Baseline Fit Exclusions GetCusors FaBaseine AutoZoom Add Peak FRAI Mulreg F From To Baseline G Left 71 875 Right 03356 Peak Region Left 1831 605 Right 1919 949 Baseline 46352 5 24 8276 x 1 7 Hold Baseline During Ft 7 Always Refit Baseline V Straight Line Baseline Expone PEAKS Peak Centroid Width Junction Amplitude Area vil o0 c s156 Mwis3s Vi J 107128 W A 3675_
89. aten 62 32 Image of the gamma ray energy list in the new table ce eeceececceceseesseeseeeeeees 62 33 Image of the Rename Objects window in Igor ce eeeccccccceccceesseeeeeeceeeeeaeaaesseeeeees 63 34 Image of the gamma ray channel list in the new table eeeeeeesssessss 63 35 Imaseor the New E e E 64 30 Image ot TE E EE 64 247 Image or the Curve FUNE panels tee 65 235 Image of the Curve oe EE 65 39 Fitting four peaks on top of a Ge sawtooth peak Note the better baseline fit aqua 40 4 42 43 44 blue lines due to the exclusion of peaks lime green that are not currently being fit in the peak fit window purple lines eese 69 a Right A triple peak fit with an appropriate baseline b Left Zoomed in view of the Igor peak fitting report outlined in red showing that the Peak 2 area fit outlined in aqua blue has a large error and requires adjustments to improve the fit s EE Lasers rpc a Sees EO wade niadeeeioene 69 Cartoon illustrating the comparison of the average macroscopic thermal neutron absorption cross sections from experimental and calculated data 71 Equations used to calculate the theoretical average macroscopic thermal neutron absorption cross section for bulk materials ssssseeeessssssssoerrsssssssseerrsssssssseerressssss 71 Aerial view of MCNPX geometry and space of HPGe crysta
90. ates SQAKD Blue gt Red V Moderate to steep red slope A 0 7 uim 0 20 0 60 Volcanic basalts Very deep absorption at 1 0 um Plutonic rocks Blue gt Red Figure 1 Asteroid taxonomic classifications 3 s S L 0 9 um D Relatively featureless spectrum 0 02 0 06 Primitive carbonaceous Steep red slope Organic rich compounds D T ia a liad Hydrated minerals _ Cosmic and Solar Wind Micrometeorite Solar Rays Implantation Bombardment e Sputtering Vaporization tier BAe too CCS eae Kat O POOR OSES ee Se SE ORO C e eite A IOS off pea o Pra CS OS d F KX vgglutinate Formation O isl o E FAT PIR woot es ORO ESQ FOP PS ec 50 Figure 2 An illustration of the different types of space weathering processes that alter the surface geochemistry of asteroids 4 What Do We Know About Asteroids What is the State of the Asteroid to Meteorite Connection Carbonaceous chondrites the most primitive and unaltered type of meteorites known have an elemental composition that is likely similar to that of the nebula from which the Solar System formed Carbonaceous chondrites are thus of particular interest to the scientific community since they are a possible source of Earth forming planetesimals 5 and contain volatiles water and organic materials that could be biogenic precursors Planetesimals formed in the outer portions of the asteroid main belt have been advocated by some
91. ayered and the C type asteroid 1s homogenous PNG He3 Th n detector HPGe y ray detector He Epi n detector 1 8 m x 1 8 m x 0 9 M Columbia River Basalt Monument Figure 8 Image of PING components on the C type asteroid simulant 26 Epithermal Neutron Flux Distribution with Penetration Depth 6 00E 06 79 C Type Asteriod Basalt Layering Simulant 5 00E 06 4 00E 06 3 00E 06 7 2 00E 06 Neutron Flux neutrons cm 1 00E 06 4 0 00E 00 4 0 Neutron Penetration Depth cm Thermal Neutron Flux Distribution with Penetration Depth 8 00E 06 1 7 C type Asteriod Basalt Layering Simulant 7 00E 06 6 00E 06 4 5 00E 06 4 4 00E 06 3 00 06 2 00E 06 Neutron Flux neutrons cm 1 00E 06 1 0 00000 0 5 10 15 20 25 30 35 40 45 50 Neutron Penetration Depth cm Figure 9 Graphs of the MCNPX computer modeling results of the epithermal and thermal neutron flux distribution as a function of neutron penetration depth for the C type asteroid blue and the basalt layering asteroid simulant red Experimental Rock Configurations PING was tested on a total of 10 experimental rock configurations summarized in Table 1 and described in detail in Appendix II to determine the sensitivity to elements 21 necessary for biogenic precursors such as C O S and H and for rock forming elements to unveil the volatile and organic natu
92. between the PNG pulse and the acquisition electrons you will want to use the SOURCE PULSE and DELAY 1 PULSE connectors THE DELAY 2 PULSE connector is not active in our PNG Figure 7 Source Pulse and Delay 1 Pulse Connectors i Lynx PHA coincidence acquisition connections Connect a BNC cable from the SOURCE PULSE or DELAY 1 PULSE connector on the PNG electronics enclosure to the Lynx GATE connector on the back of the Lynx box PNG Operations Manual 02 02 2011 Page 6 of 11 138 li Lynx PHA synchronization acquisition connections Connect a BNC cable from the SOURCE PULSE or DELAY 1 PULSE connector on the PNG electronics enclosure to the Lynx SYNC connector on the back of the Lynx box 5 Turn on the power to the PNG There is one KEY SWITCH three LEDs and a locking RED POWER BUTTON located on the top of the PNG electronics enclosure The steps to turn on power to the PNG are as follows De E CM 7 E X RED LED NEUTRONS ON Figure 8 PNG Top View a Turn and release the large red power button to enable power to the PNG The GREEN LED will light up indicating that the electronics are powered up and the YELLOW LED will light up indicating the PNG interlocks are all satisfied The main AC DC power button will power up the PNG when twisted turn clockwise and will turn off power to the PNG when depressed b Insert the bronze key into the key switch and turn the key 74 turn clockwise This will energize the PNG putti
93. box Set up the HVPS disable box inside Building 206 next to the computer Insure that the red twist button is pushed down on the HVPS disable box so that neutrons are not inadvertently produce during set up Twist and release the button when you are ready to produce neutrons HIGH VOLTAGE POWER SUPPLY DISABLE Figure 3 a Interlock Connector b HVPS Disable Box PNG Operations Manual 02 02 2011 Page 4 of 11 136 d RS232 TO ETHERNET ADAPTER CABLES Connect the RS232 end of the RS232 to Ethernet adapter to the RS232 port on the PNG electronics enclosure Connect the gray Ethernet cable between the RS232 to Ethernet adapter and the Ethernet switch to communicate to the host PC Figure 4 a RS232 Connector b RS232 to Ethernet Adapter e NEUTRON LAMP CABLE Place the neutron lamp in a visible location on top of the granite or basalt monument at a safe distance from the PNG The neutron lamp cable must be connected to the LAMP connector on the electronics enclosure for the PNG to run b Neutron Warning Lamp Figure 5 a Lamp connector PNG Operations Manual 02 02 201 1 Page 5 of 11 137 f AUXILIARY JUMPER CABLE Insure that the auxiliary jumper cable is attached to the AUXILIARY connector on the electronics enclosure This must be connected for the PNG to run Figure 6 Auxiliary Connector g ADDITIONAL CABLES SOURCE PULSE amp DELAY 1 PULSE CABLES If you are running an experiment that requires synchronization
94. c lines shown in Table 3 These gamma rays are also produced in the other two spectra by delayed activation reactions see Table 2 Therefore the 1779 and 6129 keV gamma ray lines in the summed spectrum have a better statistical precision of 0 48 and 1 10 as compared to 1 00 and 1 67 inelastic spectrum and 0 52 and 1 42 delayed activation spectrum because there are more counts in the summed spectrum Gamma ray peaks will obviously have the best statistical precision if the counts recorded at all times are summed However when there are times where counts are produced by more than a single reaction on a single element there is no longer a linear 48 relationship between the counts in the peak and the concentration of a single element To get the most accurate result for an element s concentration it is thus necessary to remove all of the counts measured at times when they can be produced by multiple reactions or by different elements see Table 2 While this procedure may reduce the statistical precision somewhat it significantly improves the accuracy which would otherwise be deteriorated by assigning counts to the wrong element This problem can be seen when looking at the data for the 1779 keV peak in Table 3 One would like to have the 1779 keV peak that occurs during the high energy neutron pulse be only due to silicon However there is also a peak at the same energy that is due to the delayed activity of aluminum Since dela
95. cable between the Lynx GATE and the PNG Source Pulse BNC connectors c Set up a second Lynx DSA as explained in section 3a on page 4 of this manual d Connect a skinny BNC extension cable between the HPGe Output 2 cable connector and the Lynx Energy connector on the second Lynx DSA e Connect a BNC cable between the Lynx GATE on the second Lynx DSA and the PNG Delay Pulse 1 connector PNG Operations Manual 02 02 201 1 P age 8 of 8 132 Julia G Bodnarik NASA Goddard Space Flight Center Code 691 27 fan 2 04 2011 133 Table of Contents Pulsed Neutron Generator Setup riii esos ie Iunceus SEENEN ENEE ENNEN 3 Connect the Cables iotbebhNc eese nennen nennen nnne ens 3 Turn On the Power to the nh 7 Pulsed Neutron Generator SelUp ui reci tabu vba ced NR UC E FExd Eed Pair UE 8 Open Ine PING GU ll eT Tc TP 8 Set the Beam Current and HV 0 cccccccccessseeccecee ceaeeeeeeeeceseeaeeeeceeeesesee rennen serena nnn nnns 9 Setup me E 9 otan ME PNG EE 10 Standby the PN 11 op he PNO e 11 PNG Operations Manual 02 02 2011 Page 2 of 11 134 Pulsed Neutron Generator Setup The steps to setup and run the Thermo Scientific MP320 Pulsed Neutron Generator PNG are as follows 1 4 Insure the PNG is setup in a safe area the GGAO Test Site consistent with federal regulations and the NASA GSFC Radiation Safety Office approved Radiation Producing Source Operati
96. carus 200 698 701 3 From An Introduction to Asteroids a Fact Sheet accompanying Asteroid Sample Return A Many Layered High Payoff Multiple Choice Problem by Dante Lauretta Joe Nuth Carl Hergenrother Bashar Rizk John Oberright John Galloway John Marshall Jason Dworkin Dave Folta Frank Vaughn Vladimir Lumelsky Bob Jenkens Bill Cutlip and Laura Via presented to NASA Headquarters Science Mission Directorate October 7 2008 4 Illustration created by Sarah Noble at NASA GSFC http www interplanetsarah com SpaceWeathering html 5 Nuth J A 2008 Earth Moon Planet 102 435 445 6 Morbidelli A Chambers J Lunine J I Petit J M Robert F Valsecchi G B and Cry K E 2000 Source regions and time scales for the delivery of water to Earth Meteoritics amp Planetary Science 35 1309 1320 7 Burbine T H McCoy T J Meibom A Gladman B and Keil K 2002 Meteoritic parent bodies Their number and identification Asteroids IIT 653 667 8 Clark B E Ziffer J Nesvorny D Campins H Rivikin A S Hiroi T Barucci M A Fulchignoni M Binzel R P Fornasier S DeMeo F Ockert Bell M E Licandro J and Moth Diniz T 2010 Spectroscopy of B type asteroids Subgroubs and meteorite analogs Journal of Geophysical Research Planets 115 E14 9 Bus S J and Binzel R P 2002 Phase II of the small main belt asteroid spec
97. ce and over an area with a 1 m radius PING also employs gamma ray and neutron detectors to measure the energies and fluxes of the emitted gamma rays and scattered neutrons that reach the surface Since each isotope emits gamma ray lines at characteristic energies the measurement of their count rates is used to determine how much of each element is present in the soil The neutron detector count rates are used to determine hydrogen content such as in hydrous minerals and water the bulk thermal neutron absorption cross section and soil density distributions Since high energy neutrons and gamma rays travel far into the regolith PING can make deep subsurface measurements over a large area without the need for any kind of mechanical penetration of the surface 11 Rover Neutron Y ray Detectors Detector cb I D fast n f is Py Te ix io dE y ray from y ray from delayed inelastic neutron scattering activation Y ray from neutron capture y ray from radioactive decay Figure 3 Illustration of PING mounted on a rover showing how it can be used to determine the bulk elemental composition over a 1 m surface area and down to 50 cm below the surface of an asteroid PING is a landed instrument that consists of three basic components 1 a PNG that emits intense pulses of fast 14 MeV neutrons that are either scattered or captured by the nuclei in the planetary material below the instrument 2 a gamma ray spectrometer to measure the
98. ce these effects and obtain higher gamma ray line sensitivity with increased signal to noise by recording gamma ray time and energy in an event by event mode synchronized to the start of each PNG pulse We use our custom MultiScan software and the Canberra Lynx DSA in TLIST mode to record the energy and time temporal resolution 0 1 us of each event detected during a PNG pulse cycle We obtain a master data set that is not limited to predetermined coincidence timing gates set for specific nuclear processes This master data set can be sliced in many ways without loss of information or requiring additional measurements with different data acquisition window settings Figures la and b illustrate the results of our post processing of TLIST gamma ray data for various timing windows The sharp lines shown in this figure are merely used to demonstrate how one can take advantage of time slicing gamma ray data An important benefit of this technique 1s that for specific gamma ray peaks different windows may be selected than those that apply to the bulk of the data For example a 40 delayed activation peak that does not interfere with a capture peak can have an analysis window that starts well before the bulk of the capture gamma rays have disappeared a ge d Natural Radioactivity di Delayed p Activation Inelastic Thermal Scattering Mate e i Capture b Inelastic Scattering Thermal Neutron Capture Delayed Act
99. cerning the nature of these objects What are the Advantages of In Situ vs Orbital Neutron Gamma Ray Measurements The key differences between ground based in situ and orbital neutron gamma ray measurements are their excitation source and their spatial resolution in situ neutron gamma ray instrumentation can utilize a pulsed neutron generator source while orbital neutron gamma ray instruments utilize cosmic rays In addition the spatial resolution or radius of the area probed for in situ measurements is 1 m in radius as compared to orbital measurement spatial resolutions proportional to the altitude of the spacecraft above the surface of the object being probed on the order hundreds of kilometers in diameter The advantages of using a Pulsed Neutron Generator PNG on the surface are 1 a known mono energetic 14 MeV neutron source 2 a flux of neutrons much greater than available from GCRs and 3 the pulsed nature of the neutron flux PNGs are superior to other neutron sources such as cosmic rays and radionuclides 28 for the excitation of subsurface materials PNGs can produce neutron fluxes several orders of magnitude greater than that from cosmic rays and unlike cosmic rays or radionuclides provide a monoenergetic neutron source that makes measurements easier to model and interpret Most importantly pulsing the neutrons permits discrimination between gamma rays produced promptly by inelastic scattering of the fast neutrons obse
100. ces only the epithermal signal The bare He 3 tube predominantly detects the thermal neutrons since He 3 has a higher cross section for thermal than for epithermal neutrons and provides a predominately thermal neutron signal The neutron energy distribution and the time dependence of these signals produced by a pulsed neutron experiment like PING can be interpreted to provide information on layering configurations hydrogen content average atomic density and soul porosity 58 59 Studying the Subsurface Elemental Composition of Asteroids Using PING Testing PING on Earth An earlier PING prototype was tested in 2006 by J Trombka s Goddard Space Flight Center GSFC X ray Gamma Ray and Neutron Instrumentation group indoors at Schlumberger s Princeton Technology Center PTC This first prototype consisted of Schlumberger s PNG and NASA GSFC s HPGe and neutron detectors that were suspended using a wooden frame over a meter sized plastic tub filled with crushed stone with varying amounts of water Unfortunately these initial test results were ambiguous due to many factors including neutron interaction with everything in the room including the samples being tested The test took place in a small room that included a lot of high Z and hydrogenous material so that there was a high probability of both neutrons and gamma rays scattering off the room walls and contents and back into the detectors This dissertation differs significantly from
101. cle produced electrons As shown in the reaction 63 in Figure 14 a neutron colliding with a He nucleus will produce a proton at 764 MeV which will ionize the gas Figure 14 also shows a schematic of a gas detector where approximately 25 000 ions and electrons are produced per neutron 4 x 10 coulomb and the cross section for He The only difference between the bare He thermal neutron detector and the Cd wrapped He detector is that the bare He detector predominately detects thermal neutron due to the high cross section of He for n detection and some epithermal neutrons while the Cd on the Cd wrapped epithermal neutron He detector absorbs the thermal neutrons and hence mainly detects epithermal neutrons due to the high cross section of Cd to absorb thermal neutrons 35 n He gt H H 0 76 MeV g 5333 barns 18 Figure 14 Schematic of a He neutron gas detector Lynx DSA Electronics and Acquisition Software A Canberra Lynx DSA is used to acquire data from each gamma ray and neutron detector used for a PING measurement Figure 15 a and b are an images of the front and back of the Lynx DSA A more detailed description of While the Lynx DSA hardware 64 features multiple data acquisition modes including coincidence gated Pulse Height Analysis PHA and event by event TLIST mode operation of the Lynx DSAs in TLIST mode required the development of custom software Lynx DSA data acquisition can be performed using e
102. ctor Connect the yellow power is plugged Ethernet cable from here to the Ethernet switch in and OFF when connected to the computer it is unplugged Figure 2 Important Lynx DSA rear panel connectors for the LaBr3 LaCl3 detector ii Locate the 12V 12V BR2 preamp female connector the HV SHV connector and a SIGNAL BNC connector on the LaBr3 LaCl3 detector preamplifier voltage divider base shown in Figure 3 PNG Operations Manual 12V 12V this is the detector preamp power connection Connect the BR2 male preamp power connector here HT this is the HV connection Connect SHV HV Signal this is the cable here detector signal output Connect BNC cable here Figure 3 LaBr3 LaCl preamplifier voltage divider base connection ports 02 02 2011 P age 5 of 8 129 iii Connect the LaBr LaCl detector preamplifier power Connect the cable with the 9 pin male BR2 connector between the Lynx s PREAMP connector and the scintillation detectors preamplifier 12 V 12 V power connector The 9 pin male connector end of the cable shown in Figure 4a will be connected to the 9 pin female connector labeled PREAMP on the back of the Lynx DSA shown in Figure 2 The BR2 male connector end of the cable shown in Figure 4b will be connected to the 12 V 12 V BR2 female connector on the back of the scintillation detector shown in Figure 3 The PREAMP connector on the back of the Lynx includes a bail mechanism that your shoul
103. d Peak Region Folder Make csv files Load Background Control Waves Save Background Control Waves Background Report Load Epoch Peak Params Edit Epoch Peak Params Figure 22 Image of the Gamma menu 56 e Under the Spectrum menu select your wave Spectrum Wave wavename EN From To Baseline Add Left 409 6 Right 3686 4 Remove Peak Region Clear All Left 1228 8 Right 2867 2 onsolidat Baseline 0 0 x 0 7x42 7 0 2 Pass Peaks Fit v Hold Baseline During Fit V Always Refit Baseline PEAKS C Straight Line Baseline _ Exponential baseline Peak Centroid Widti ad Epoch Paran ad Peaks Paramete ave Paramete Report Fit Folder Figure 23 Image of the Fit Gauss With Tail window 57 e On the graph zoom in close to desired peak with purple cursors as close to peak as possible and blue cursors fitting the trend of the background If cursors are not visible on screen cluck Get Cursor Then select the round cursor at the bottom left of the screen and drag it to the peak so your window resembles the above image s wave wavename beste pnt 910 JE pnt Figure 24 Fit Gauss With Tail gamma ray spectrum window e Click Add Peak if a different peak type is desired select it here Additionally if the user wishes to account for a Doppler broadened peak select the checkbox If not click OK 1 8 0 0 AddPeakTypePanel Peak Typ
104. d have a spatial resolution proportional to the altitude of the spacecraft above the surface of the object being probed Thus remote sensing GRS and or NS orbital and close fly by missions e g Lunar Prospector 20 Mars Odyssey 21 22 Dawn 23 MESSENGER 24 NEAR 25 and LRO 26 27 typically require long observation times on the order of months to years since they rely on GCR interactions with the regolith Consequently both the orbiting spacecraft s distance to the planet and the GCR flux greatly affect the probability of detecting gamma rays and neutrons emanating from the surface What Do We Want to Know About Asteroids and How Can We Get the Information What Do We Not Know About Asteroids The laundry list of what is not known about asteroids is lengthy As mentioned previously there is current lack of information on multiple spatial and depth scales that greatly hinder our understanding of primitive asteroids To strengthen the connection between the geochemistry of carbonaceous meteorites to C type asteroid parent bodies as well as test current and future theories about subsurface H reservoirs space weathering effects solar system formation and evolution and possibly the origin of life it is necessary to obtain in situ subsurface bulk elemental composition information about these asteroids to infer their subsurface mineralogy and compare it with other observations to create a more detailed picture that will aid in dis
105. d use to secure the preamplifier s power cable to the Lynx DSA Figure 4 a Preamp 9 pin male connector b Preamp BR2 male connector iv Connect the LaBr LaCl detector positive HV power The LaBr4 LaCls detectors require positive high voltage power Connect the SHV cable shown in Figure 5 between the detector preamp s HT a k a HV connector shown in Figure 3 and the Lynx s HV connector shown in Figure 2 Figure 5 Example of a SHV Cable v Connect the LaBr LaCl detector BNC gamma ray signal cable to Lynx Connect a BNC cable shown in Figure 6 from the SIGNAL connector on scintillation detector s preamplifier voltage divider base shown in Figure 3 to the ENERGY connector on the back of Lynx shown in Figure 2 Figure 6 Example of a BNC cable PNG Operations Manual 02 02 2011 P age 6 of 8 130 b Connect a HPGe gamma ray solid state detector to a Lynx DSA i Locate the HV ENERGY PREAMP HV INH and the TRP INH connectors on the Lynx DSA The Lynx DSA shown in Figure 7 has several rear panel connectors of interest including a HV SHV connector a HV SHV connector a 9 pin female PREAMP connector a 12V DC Power connector for the Lynx AC power adapter and an Ethernet connector The Energy signal comes in here Connect the BNC cable from here to the detector signal output VAIDOOOO c 2004 PRA ACO SS SYNC CHGR ADY CHOR ROY we c mcs SWEEP ADY CH ADY wes aca ss fart JALA CP vo amp
106. df 120417He2TLTOO2 log pdf 120418He2TL TOOI log pdf Ice 2 The experimental configuration was constructed however due to time constraints no data was collected Data will be collected in the future for this configuration Ice 3 The available data for the Ice 3 configuration 1s as follows e 120507Gel TLTOOI I log pdf 120507Gel TLTOOI 1 capture filtered pdf 120507GelTLTOOI 1 DANA filtered pdf 120507Gel TLTOOI 1 inelastic filtered pdf e 120507Gel TLTOOI 2 log pdf 120507Gel TLTO0OI 2 capture filtered pdf 120507Gel TLTOOI 2 DANA filtered pdf 120507Gel TL TOOI 2 inelastic filtered pdf e 120508Gel TLTOOI 1 log pdf 120508GelTLTOO1 1 capture filtered pdf 120508Gel TLTOOI 1 DANA filtered pdf 120508Gel TLTOOI 1 inelastic filtered pdf The thermal and epithermal neutron data is listed in the following files e 120507Hel TLTOOI 1 log pdf e 120507Hel TLTOOI 2 log pdf Concord Grey Granite Monument Concord Grey Granite PING Experimental Configuration Figure 47 shows a picture of the PING instrument set up on top of the Concord Grey granite monument The PNG is on the left hand side of the granite monument followed by the epithermal and thermal He 3 neutron detectors in the center and the HPGe detector on the right hand side of the granite See Figure 50 for PING equipment dimensions and spacing 119 Figure 47 Image of the PING instrument prototype on top of the Concord Grey Granite monument Columbia River
107. e Peak Region Clear All Left 306 639 Right 812 378 onsolidat Baseline 6694 79 15 6936 x 0 00895418 x 2 1 1 2 Pass Peaks Fit V Hold Baseline During Fit V Always Refit Baseline PEAKS Junction _ Straight Line Baseline _ Exponential baseline Peak Centroid Width 0 209 599 C Ese Fixed Amplitude Area 0 817051 1 25 Fixed Fixed 9295 64 1349355 Fixed Delete vad Epoch Paran ad Peaks Paramete ave Paramete Report Fit Folder Figure 28 Setting all of the peak parameters to Fixed 60 Repeat for all four energies eg 1779 5107 5618 6129 When finished select Report at the bottom of the tail fit window eoo Compact Param Report 0 1 e 3 4 D EE t t t t t t a E Peak Source Centroid Centroid Area Area Width sigma Sigma 12 20 2012 15 31 01 1 000 S wave wavename Rob was here Peak O 909 5991 Fixed 13485 5235 Fixed 8170512 Peak 1 2089 0000 Fixed 1033 84878 Fixed 2 470864 Peak 2 2298 0000 Fixed 1298 37902 Fixed 2 958585 Peak 3 2307 0000 Fixed 1388 986895 Fixed 2 668306 EL Figure 29 Image of the Compact Parameter Report window Copy the data from the Compact_Param_Report window and put it into an Excel file Copy the information in the third column under Centroid eoo F Workbook1 wa 8 ffj G Ed amp o6 5 I o w E 2o E elt o e Q Search in Sheet f Home Layout
108. e Gauss Tail _ Doppler broadened OK CANCEL Figure 25 Add Peak Type window 58 e Under Centroid and Width set both options to Free and set Junction to Fixed and enter in a value of 100 eoo tailfit panel Spectrum Wave wavename Baseline Fit Exclusions From To Baseline Add Left 884 763 Right 542 163 Remove Peak Region Left Right 912 378 Baseline 669 4 79 15 5835 x 000895418 x 2 1 2 Pass Peaks Fit vf Hold Baseline During Fit vf Ahways Refit Baseline m straight Line Baseline PEAKS Peak Centroid Widtl lunctior Amplitud p log 181396 1 25 732061 C Ese Free Free Calc Free had Epoch Paran ad Peaks Paramete ave Paramete Report Figure 26 Peak parameter values for the new peak added in the Fit Gauss With Tail panel 59 Clear All onsolidat _ Exponential baseline Area 27420 1 Delete Fit Folder On the graph click Fit AID tailfit Graph s wave wavename et Cursor it Baselin uto Zooi Add Peat REAN Aulreg Fi Indo Mov AJ s wave wavename NA mie 1 Figure 27 Selecting the Fit All button the Fit Gauss With Tail spectrum graph e Under each option set status to Fixed Spectrum S wave wavename Baseline Fit Exclusions To Baseline Add Left 884 769 Right 942 163 Remov
109. e asteroid In addition the asteroid simulant must be located in a region free from any nearby structures this can be achieved by using the outdoor planetary neutron and gamma ray instrumentation testing facility described in Chapter II 18 To meet these requirements an asteroid simulant was constructed using alternating layers of basalt and polyethylene on top of a basalt monument located at the test facility at NASA GSFC based on Monte Carlo N Particle eXtended MCNPX computer modeling results and Activation Laboratories ACTLabs located in Ontario Canada elemental assay information PING experimental gamma ray and neutron data were collected on the granite and basalt monuments the asteroid simulant and other various layering configurations The experimental data taken on the two monuments and the asteroid simulant were analyzed and compared with MCNPX models to quantitatively determine and verify the elemental composition sensitivity and precision of PING measurements for selected elements 19 CHAPTER II EXPERIMENT DESCRIPTION Design of the Goddard Geophysical and Astronomical Observatory GGAO Neutron Gamma Ray Instrumentation Test Facility Neutron Gamma ray Instrumentation Test Facility The work presented in this section is from J Bodnarik L Evans S Floyd L Lim T McClanahan M Namkung A Parsons J Schweitzer R Starr and J Trombka A Unique Outside Neutron and Gamma Ray Instrumentation Development
110. e asteroid simulant data with the HPGe detector wrapped in a boronated rubber cap for different timing windows during the PNG pulse period total acquisition live time 46 15 hrs for the asteroid simulant experiment The symbol means that it is the excited state of the isotope 1 e SS Mo means that it is the excited state of Mg through the m or Mg reaction Thermal N eutron Capture Delayed Activation Inelastic Scattering Window amp Natural Activity cts 3009 10 5 ng 13073 10 3 69 Ge K 9323 2287 20874 6376 Fe n pp Fe n pp Mg n yB 47839 Mo n yp 182841 Mnn yB Mn n yp a 2 ge amp 5 78 ER 15459 127 86610 0 65 28 Si n pp 34659 24152 56 Fe n pp 1562 1018 2 2203 MEE Ge i 762 2211 Alma We CU Bi 3987 2223 Hy KH 2614 Th TI 74967 4957 4438 S 26327 1 00 mi ASTh 9T 18979 16 O n n y 6129 am On pi NIS OO wli oo in N Or SIE gt A olo Mo WN CO Once the gamma ray lines have been fit during different time windows during the PNG pulse period the next step is to subtract out any contributions due to different processes on multiple elements so that one is left with a gamma ray line due to a single process on a single element Tables 10 11 and 12 show the results and uncertainties for 83 the line cleaning of the elements listed for the granite monument th
111. e basalt monument and the asteroid simulant configuration The elements that were selected were based upon the MCNPX model results for the inelastic window Each of these tables lists the gamma ray line energy E in units of keV the gamma ray line identification ID the gamma ray line intensity Ig in units of cts and the relative uncertainty ol in units of 9o in a time window over the total live time acquisition of 16 21 hrs for the granite monument 15 23 hrs for the basalt monument and 46 15 hrs for the asteroid simulant where the inelastic window for the n n y gamma ray reactions is 10 100 us the capture window for the n y gamma ray reactions is 150 650 us and the delayed activation and natural activity window 1s 650 1000 us Table 10 Gamma ray line cleaning results and uncertainties for the granite monument 3Na n n y 17144 19 04 1779 Z nn 73439 221 Alnny 54l86 096 Table 11 Gamma ray line cleaning results and uncertainties for the basalt monument 5Na nn y 18086 1779 Si nny 53124 484 6129 oan 224655 099 84 Table 12 Gamma ray line cleaning results and uncertainties for the asteroid simulant wen P d o keV cts 96 Nana 9792 1779 8Si n n y 55577 1811 gt Fe n n y 80854 2211 Al nanv 65796 lc n n y 74967 9 44 4 e 6129 O n n y 25371 Next determining elemental ratios is an interim step to calculating elemental
112. ear Earth Asteroid Rendezvous Shoemaker NEAR Shoemaker Mission was the first mission to orbit an asteroid and included both an onboard XRS and GRS in its instrument suite The XRS and GRS measured both naturally occurring radioactivity X rays and GCR induced gamma rays were used to determine the elemental composition and geochemistry of the surface and subsurface of the Eros asteroid However many complications throughout the mission including low GRC flux due to being at Solar maximum and an incorrect radial distance orbital insertion distance around Eros yielded little usable information about the bulk composition of the asteroid The most useful XRS and GRS information was obtained when the NEAR Shoemaker spacecraft made a soft crash landing on the surface of Eros Both the orbital and in situ measurements relied solely on GCRs as the excitation source to produce gamma rays used to infer the geochemistry of the Eros 30 Although progress has been made in understanding the nature of primitive asteroids it is clear that additional geochemical information is needed to link primitive meteorites with their associated asteroid parent bodies One way to address this problem is to use in situ non destructive neutron gamma ray analysis techniques that can measure the bulk subsurface elemental composition These measurements can be used to infer mineralogy H content and other properties that can be compared with results from various other
113. econd Ethernet port on the back of the Z series main operations computer and the other Ethernet cable is conneted to the second Ethernet port on the back of the Dell backup operations computer iii Run these cables from the building out to the monument iv Connect each long red Ethernet cable into its own separate Ethernet switch by plugging each long red Ethernet cable into one of the Ethernet switch ports labeled numbers 1 through 7 on the Ethernet switch v Proved power to the Ethernet switches by attaching the Ethernet power cords between the Ethernet Switches and a power strip Equipment Setup for PNG Experiments The steps to setup the equipment to run PNG experiments on the granite or basalt monument are as follows 1 Setup the PNG on the monument Refer to the MP320 PNG Quick Start Operations Manual 2 Setup a platform for the electronics by placing the closed large white PNG container or the large wooden HPGe container next to the monument on top of its wooden 4 x 4 supports 3 Setup the Lynx DSA s The quantity of Lynx DSA s and their setup will depend on the experiment a Basic setup for a Lynx DSA This section only explains how to setup power and communications to a single Lynx DSA without connecting a detector Detector and acquisition mode specific connections will be explained in subsequent sections of this manual i Place the Lynx DSA the Ethernet switches and the power strips on top of the large containe
114. eeper sensing bulk measurement techniques to discern the bulk composition and nature of C complex asteroids The main source of elemental composition information for C complex asteroids 1s from their optical Ultraviolet UV Visible VIS Near Infrared NIR and Infrared IR properties which include their spectral reflectance characteristics albedo polarization and the comparison of optical spectroscopy with meteorite groups corresponding to asteroids of every spectral type However these spectral reflectance measurements used for asteroid taxonomy are not particularly informative due to the lack of strong spectral features Figure 1 shows the asteroid taxonomy classifications demonstrating our minimal understanding of asteroids from UV VIS and IR measurements With two exceptions 1 2 there is no direct link between meteorites and their parent body asteroids For example a given meteorite may be determined to be from a C complex family of asteroids but we don t know which asteroid taxonomic type it belongs to Finally UV VIS and IR measurements are limited to probing the first few microns of the surface of asteroids However we know that these top microns are strongly space weathered from solar wind exposure micrometeorites etc and are substantially different from the bulk material as seen in Figure 2 Consequently these sources of information reflect observations from widely contrasting spatial scales a lack of in situ me
115. eir selected timing windows during the PNG 1000 us period inelastic window 10 100 us capture window 150 650 us and delayed activation and natural activity 650 1000 us for the PING granite monument experiment that was run for a total acquisition live time of 16 21 hours Table 8 lists the intensities and uncertainties of the gamma ray 80 lines analyzed and their selected timing windows during the PNG 1000 us period for the PING basalt monument experiment that was run for a total acquisition live time of 15 23 hrs Table 9 lists the intensities and uncertainties of the gamma ray lines analyzed and their selected timing windows during the PNG 1000 us period for the PING asteroid simulant experiment that was run for a total acquisition live time of 46 15 hrs Table 7 Gamma ray line intensities and uncertainties for the PING granite monument data with the HPGe detector wrapped in a borated rubber cap for different timing windows during the PNG pulse period total acquisition live time 16 21 hrs The symbol means that it is the excited state of the isotope 1 e E Mo means that it is the excited state of Mg through the 25Si n o Mg reaction Delayed Activation amp Natural Activity p ge u cts cts 1213 EN ON LA ge 9 Ge4 K 228 74 2084 26812 Fe n pp Mg n yB Mn n yp 8519 8 68 Mg nyp 5882 7 87 135102 0 ERG CE 9388 4 Si n pp Alma Fe n pB Mg n
116. el TLTOOI 2 log pdf 121 104Gel TLTO0OI 2 capture filtered pdf I121104Gel TLTOOI 2 DANA filtered pdf 121 104Gel TLTOOI 2 inelastic filtered pdf 110 The thermal and epithermal neutron data is listed in the following files 111005Hel TLTOOI log pdf 111005He2TLTOOI log pdf Basalt The available data for the Basalt configuration is as follows 110821 Gel TLTOO2 log pdf 110821 Gel TLT002 1 capture filtered pdf 110821 Gel TLTOO2 1 DA filtered pdf 110821 Gel TLTO002 1 inelastic filtered pdf 110821 Gel TLTO0O3 log pdf 1 10821 Gel TLT0O03 1 capture filtered pdf 110821 Gel TLTO0O3 1 DA filtered pdf 110821 Gel TL T0O3 1 inelastic filtered pdf 110822Ge1TLT005 log pdf 110822GelTLTOOS 1 capture filtered pdf 110822Ge1TLT005 1 DA filtered pdf 110822Gel TLTOOS 1 inelastic filtered pdf 110822Gel TLTOOO log pdf 110822Gel TL T0O6 1 capture filtered pdf 110822Ge1TLT006 1 DA filtered pdf 110822Gel TLTO00O6 1 inelastic filtered pdf 110822Gel TLTOOS log pdf 110822Gel TLTO0OS 1 capture filtered pdf 110822Ge1TLT008 1 DA filtered pdf 110822Gel TLTO0OS 1 inelastic filtered pdf 110822Gel TLTOOO log pdf 110822Ge1TLTOO9 1 capture filtered pdf 110822Gel TLTOOO 1 DA filtered pdf 110822Ge1TLTOO9 1 inelastic filtered pdf 110822Gel TLTOI1O log pdf 110822Ge1TLTO10 1 capture filtered pdf 110822Gel1TLTO10 1 DA filtered pdf 110822Gel TLTO010O 1 inelastic filtered pdf 121009Gel TLTO0O2 log pdf 121009Gel TLTOO2 capture filtered pdf 12
117. eport Tables 20 and 21 are the results of the independent elemental assay of the Columbia River Basalt and Concord Grey Granite performed by Activation Laboratories Ltd ActLabs in Ancaster Ontario Canada Table 20 ActLabs Columbia River Basalt Elemental Assay Report A09 1100 Final Report Report Date 7 20 2010 Activation Laboratories Columbia River Basalt Elemental Assay Activation Laboratories Ltd Ancaster Ontario Canada Analyte Symbol B Mass i west H Totai seid sio2 Azos rezosr wgl wei Cao ween UnitSymbo mal al al o ft em Detection Limit os oo onf oo aal oof aalt aal oof aal om Analysis Method JL PGNAA PGNAAL naaj mal IR Analyzer FUS ICP Fus cP FUS ICP FUS ICP FUSHICP FUS ICP Fus icP EEE Analyte Symbol KeO 209 Peos o mal ad el v cr o nf az utes S x em em em cem aem cem cep cen EE NN NES BE TET EUN ET MET AES SET ET E 115 1 499 0 48 0 08 100 1 26 1 215 350 41 150 70 100 EE AnalyteSymbo 1 Ga Ge As Ro ai wv ai wi Mo Ag vd Sn o eee ee Se ee Analyte Symbol 1 Cs Ba ta od P w Sm Eu Gd ww o zs pr AnalyteSymbo Tm Yo d Hj e wu ml a wd Gen Totals UntSymbo pom pem pem nl pom ppm pom oni nl ppm pom TDI MH EE E E E E E ST he otot E rusas el el el el el el reel el el i m 0 31 199 0 312 2 0 87 05 0 05 lt 5 04 2 83 0 72 0 01 105
118. er cap for different timing windows during the PNG pulse period total acquisition live time 16 21 hrs The 4 symbol means that it is the excited state of the isotope 1 e S Mg means that it is the excited state of Mg louem M CM M MM M E e 81 8 Gamma ray line intensities and uncertainties for the basalt monument data with the HPGe detector wrapped in a boronated rubber cap for different timing windows during the PNG pulse period total acquisition live time 15 23 hrs The symbol means that it is the excited state of the isotope 1 e x Mo means that it is the excited state of Me EEEE A PE A A E EE 82 9 Gamma ray line intensities and uncertainties for the asteroid simulant data with the HPGe detector wrapped in a boronated rubber cap for different timing windows during the PNG pulse period total acquisition live time 46 15 hrs for the asteroid simulant experiment The symbol means that it is the excited state of the isotope jg Mo means that it is the excited state of Me NEE 83 viii LIST OF TABLES CONT TABEE M PAGE 10 Gamma ray line cleaning results and uncertainties for the granite monument 84 11 Gamma ray line cleaning results and uncertainties for the basalt monument 84 12 Gamma ray line cleaning results and uncertainties for the asteroid simulant 85 13 Gamma ray element Si experimental and MCNPX ratios for the gra
119. er in addition to its neutron detectors PING also uses a PNG that can put out more neutrons per second and has the flexibility in pulse frequency and pulse width needed so that it can be tuned to work effectively with a gamma ray spectrometer as well as the neutron detectors Thus PING may be seen as the crucial next step after MSL DAN Neutron Transport Figure 4 illustrates the different physical processes that occur when planetary surfaces are stimulated by high energy neutrons Characteristic gamma rays are emitted by the nuclei in the material as they participate in the resulting inelastic neutron scattering thermal neutron capture and neutron activation processes The gamma ray energies and intensities measured by a spectrometer at the surface are used to determine elemental composition of the regolith A gamma ray spectrometer at the surface will also measure the characteristic gamma rays from the decay of naturally radioactive elements such as K Th and U that are commonly found in planetary materials No outside 13 stimulation of these elements is needed for gamma ray line production see Boynton et al 1993 48 Evans et al 1993 49 Feldman 2000 50 and Grau 1990 51 for a general overview of physics of neutron gamma ray techniques BIET y Rays from n Activation Y Inelastic Scattering Neutron Capture p Moderation N K U Th Fast Natural Seaerte Ne trons ID UI Figure 4 PING ta
120. ermal and thermal neutron detectors and the PNG are shown in the Figure 10 The same PING component spacing was used for all experimental rock configurations Appendix II has a more detailed description of both the experimental rock and PING instrument component spacing information T 6 ui 3a Com m Figure 10 Drawing of the spacing of the PING components using for each experimental configuration 20 PING Experimental Equipment Description PING employs a pulsed neutron generator to excite materials at and below a planetary surface and utilizes the penetrating nature of these fast neutrons and gamma rays to probe the subsurface soil composition over a 1 m area and down to depths of 10 100 cm PING s gamma ray spectrometer and neutron detectors measure the resulting gamma rays and neutrons that emerge from the planetary surface A gamma ray spectrometer measures the resulting inelastic scattering capture and delayed activation gamma rays emitted by the excited elements as well as gamma rays emitted from natural radioactive decay neutron detectors measure the number of the epithermal and thermal neutrons that reach the surface as a function of time relative to the initiation of each high energy neutron pulse PING gamma ray and neutron data are acquired using custom software to control digital signal analyzer electronics These data coupled with MCNPX 60 computer simulations let us quantitatively determine the bulk elemental co
121. es 7 8 and 9 Tables 7 8 and 9 are divided into four major sections the gamma ray line energy E in units of keV and three time windows during the 1000us PNG pulse period Each time window section lists the corresponding gamma ray line identification gamma ray line intensity Ig in units of counts and the relative gamma ray line uncertainty o in units of percent for time windows that contain gamma rays predominately produced by neutron inelastic scattering window 10 100 us thermal neutron capture window 150 650 us and delayed activation and natural activity window 650 1000 us Delayed activation and natural activity gamma rays are present in all of these time windows over the 1000us neutron pulse period and in some cases gamma ray capture lines may be present in the inelastic scattering window A word of caution to the reader about the gamma ray line identifications since all possible 78 gamma ray producing nuclear reactions have not been explored some of the gamma ray line energies in the different time windows may be misidentified The 440 585 847 1014 1460 1779 1811 1942 2203 2211 2223 2614 4438 and 6129 keV gamma ray lines were analyzed for each of the three configurations in Tables 7 8 and 9 The 440 keV gamma ray line is most likely produced in the inelastic f 69m window by the Na n n y reaction and the delayed activation o Zn in the capture window by the delayed activation of 9 Zn and in t
122. f 110824Ge1TLT006 1 DANA filtered pdf 110824Gel TLTO06 1 Inelastic filtered pdf 110824Gel TLTOOO log pdf 110824Gel TLTO0O06 Capture filtered pdf 110824Gel TLTOOO DANA filtered pdf 110824Gel TLTO00OO Inelastic filtered pdf 110824Ge1TLT007 log pdf 110824Gel TLT007 Capture filtered pdf 110824Gel TLTOO7 DANA filtered pdf 110824GelTL TOOT Inelastic filtered pdf 110824Gel TLTOOS log pdf 110930Gel TLTOOI log pdf 110930Gel TLTO0OI Capture filtered pdf 110930Gel TLTOOI DANA filtered pdf 110930Gel1TL TOOI Inelastic filtered pdf 120323Gel TLTOOI log pdf 120323Gel TLTOOI capture filtered pdf 120323Gel TLTOOI DANA filtered pdf 120323Gel TLTOOI inelastic filtered pdf 120323Gel TLTO00O2 log pdf 120323Gel TLTO00O2 capture filtered pdf 120323Gel TLTO002 DANA filtered pdf 120323GelTLTO002 inelastic filtered pdf 120326Gel TLTOOI 1 log pdf 120326Gel TLTOOI 1 capture filtered pdf 120326Gel TLTOOI 1 DANA filtered pdf 120326GelTLTOO1 1 inelastic filtered pdf 120326Gel TLTOOI 2 log pdf 120326GelTL TOO 2 capture filtered pdf 120326Gel TLTO00I 2 DANA filtered pdf 120326GelTLTO0OI 2 inelastic filtered pdf 120329Gel TLTOOI 1 log pdf 120329Gel TLTOOI 1 capture filtered pdf 120329Gel TLTOOI 1 DANA filtered pdf 120329GelTLTOO1 1 inelastic filtered pdf 120329Gel TLTOOI 2 log pdf 120329GelTL TOOI 2 capture filtered pdf 120329Gel TLTOOI 2 DANA filtered pdf 120329GelTLTOO1 2 inelastic filtered pdf 120330GelTLTOOI
123. f H C O Mg Na Al Fe and Ca to Si from the gamma ray data and determine the macroscopic thermal neutron absorption cross section from the thermal neutron dieway The H content was not determined from the epithermal neutron experimental and MCNPX data but it will be determined and presented in a publication in the foreseeable future Results and Interpretation Gamma Ray H C O Mg Na AI Si Fe Ca K Th and U gamma ray lines were analyzed in the experimental and MCNPX data for all three configurations These elements were chosen because they are major rock forming elements Due to their difference in concentration between both the granite and basalt monuments they are useful in differentiating between different types of asteroids Table 6 shows the selected independently assayed element concentrations wt for the granite the basalt and the CII carbonaceous chondrite meteorite analogous to a C type asteroid and used to determine and construct the asteroid simulant layering configuration that has the same neutron transport properties as this meteorite TI Table 6 Granite basalt CI1 chondrite meteorite element concentrations rr 09 0 03 2 02 C 0088 O 483 E 4497 O 4640 an 2 43E 03 5 00E 06 2 90E 06 1 39E 03 7 20E 05 8 00E 07 H C O Mg Na Al Si Fe Ca K Th and U gamma ray lines were analyzed in the experimental data for the granite basalt and asteroid simulant and are presented in Tabl
124. from the elemental assays of the granite basalt and CII carbonaceous chondrite analogous to the asteroid simulant and compared with the results obtained from the fitting of the thermal neutron dieaway data The experimental results are compared with the MCNPX results to benchmark the Monte Carlo model used to obtain the efficiency of the HPGe detector used to obtain the 71 absolute elemental weight percent concentrations used to model the epithermal and thermal neutron dieaway to obtain the H content and the macroscopic thermal neutron absorption cross section of the bulk material and provide a model that can be used to calculate the results for situations where it would be difficult to build an experimental configuration MCNPX Data Analysis MCNPX is a general use Monte Carlo radiation transport code used to track 34 different types of particles e g n p e and 2205 heavy ions for continuous energies from 0 1000 GeV using data libraries below 150 MeV n p e and h and models otherwise The user can specify the following in the input file 1 3 D object geometries using 1 and 2 degree surfaces tori ten macrobodies and lattices 2 material definitions or vacuum void for all defined objects and 3 interdependent source variables including both time dependent and time independent continuous sources 7 output tally types and many modifiers The computer code can be run on many computer platforms including Linux Un
125. he delayed activation and natural activity window by the delayed activation of mZ The 585 keV gamma ray line is most likely produced in the inelastic window from the excited state of e Mo K Mg through the A5Si n o Mg reaction the delayed activation of GetK X ray and the natural activity of STh TI in the capture window by Me n y the delayed activation of Ge K X ray and the natural activity of 5Th TI and in the delayed activation and natural activity window by the delayed activation of 9Ge K X ray and the natural activity of Th T The 847 keV gamma ray line is most likely produced in the inelastic window by Al niny and 2 Fe n n y and the delayed activation of Pepp Fe Mfo n yB AI and Mn n yp Fe in the capture window by the delayed activation of g Fe n pB Fe Mfo n yp AI and Mn n yp Fe and in the delayed activation window by the delayed activation of Fe n pB Pe Mfe n yB AI and Mn n yp Fe The 1014 keV gamma ray line is produced in the inelastic window by Al n n y and the delayed activation of Mfo n yB AI in the capture window by the delayed activation of 9Mfe n yD AI and in the delayed activation and natural activity window by the delayed activation of Mfe n yB AI The 1460 keV gamma ray line is produced in all three windows by the natural activity of K The 1779 keV gamma ray 79 line is produced in the inelastic window by 5Si nn y and the delayed act
126. he rocks Once this is achieved we have already demonstrated that a landed PING will provide very good precision in a reasonable time frame for typical mission parameters Of particular interest is the clarity with which elemental concentrations of carbon that are typical of carbonaceous asteroids can be readily obtained 98 The work reported here has firmly established that important geochemical information on asteroids based on elemental analysis and neutron transport can be obtained with instrumentation such as PING Thus a future mission to one or more asteroids can have substantially increased science return providing a direct description of the asteroid subsurface without drilling or otherwise disrupting the surface This will help provide information that can improve our understanding of the relation between meteorites and specific asteroid types Furthermore we have shown that asteroid composition can be fabricated in large volume structures on Earth which can also be modeled with MCNPX to allow direct experimental tests of specific asteroid types These asteroid simulant structures can be used together with a benchmarked Monte Carlo program to predict mission responses to optimize the science return before launch 99 REFERENCES 1 Jenniskens P et al 2009 The impact and recovery of asteroid 2008 TC3 Nature 458 485 488 2 Nesvorny D et al 2009 Asteroidal source of Lchondrite meteorites I
127. i experimental and MCNPX ratios and uncertainties are 0 548 0 70 and 0 473 1 38 differing approximately by a factor of 1 2 Table 13 Gamma ray element Si experimental and MCNPKX ratios for the granite In general all of MCNPX ratios are less than their corresponding experimental ratios by an average factor of 8 7 with the exception of the O Si ratios that differ by an average factor of 1 5 which puts the O Si experimental and MCNPKX ratios in fairly good agreement with one another However the Na Si Al Si and Fe Si experimental and MCNPX ratios are in poor agreement This poor agreement can be due to the fact that the experimental ratios take into account everything in the experiment while the MCNPX model was constructed using only a point neutron source for the PNG and an isolated HPGe crystal for the HPGe detector located at approximately the correct distance and location from the PNG The model did not include the HPGe detector housing and dewar the PNG housing or either of the neutron detectors The locations of the detectors and PNG were at the same approximate locations as on the granite monument The absence of these pieces of equipment could explain the low value of the Al S1 and Fe Si ratios since the PNG housing and the HPGe housing and dewar contain a great deal of AI 86 and some steel which contains Fe The low value of the MCNPX Na Si ratio as compared to the experimental ratio could be explained by the contribut
128. igure 38 Image of the Curve Fitting graph 65 5 The preceding steps are repeated for all spectra for each particular time window for each PING experiment configuration Putting Energy Calibrated Spectra on One Energy Scale Using Igor Pro 6 2 Each set of spectra for a given configuration and time window is put on one energy scale using a linear calibration that worked well for the data sets considered so there was not need to consider higher order polynomials and then summed together to increase the total number of counts and precision of the gamma ray lines This is accomplished by using the Igor interpolate2 function Let ywavel ywave2 ywave3 etc represent thel D spectral arrays waves that were individually calibrated for one configuration and time window and xwavel xwave2 xwave3 etc represent the waves that contain the energy scale for their corresponding spectra counts We use the interpolate2 Igor Pro routine to create ywave2_interp so that it has the same number of bins points as ywavel and corresponds to the spectral counts in xwavel In other words the ywave interp waves are shifted to a specified energy scale In this use of Interpolate2 the destination XY pair is ywave2_interp vs xwavel So xwavel is the destination X wave By setting I 3 we specify that the interpolation be done at the X values specified by the destination X wave The destination X wave 1s therefore not changed The destination X wave must already exi
129. ion of another element present in addition to Na that produces a gamma ray line that overlaps in energy with the 440 keV gamma ray line As seen in Table 14 for the PING basalt monument experiment the Na Si experimental isotopic ratio and uncertainty is 0 340 19 05 as compared to the MCNPxX ratio and uncertainty that is 0 050 13 97 Even with the large uncertainty associated with the each ratio the two ratios differ approximately by a factor of 6 8 The Al S1 experimental ratio as compared to the MCNPX ratio is 0 171 14 82 and 0 068 3 84 and they differ approximately by a factor of 2 5 The Fe Si experimental and MCNPX ratios and uncertainties are 0 820 1 17 and 0 010 40 29 even with the large uncertainty on the MCNPX ratio both ratios differ approximately by a factor of 82 The first O Si experimental and MCNPX ratios and uncertainties are 0 209 4 22 and 0 113 3 28 and they differ approximately by a factor of 1 8 The second O Si experimental and MCNPX ratios and uncertainties are 0 408 1 27 and 0 536 1 51 and differ approximately by a factor of 0 8 Table 14 Gamma ray Element Si experimental and MCNPKX ratios for the basalt In general all of MCNPX ratios are less than their corresponding experimental ratios with the exception of the second O Si ratio that is in more agreement with the 87 experimental ratio The Al S1 experimental ratio as compared to the MCNPX ratio differs by an approximate average f
130. ite by studying the time profile of thermal neutron absorption between PNG pulses using He thermal neutron detectors at the surface Figure 6 is a cartoon demonstrating how we can compare the average macroscopic thermal neutron absorption cross sections of the fitted experiment data to that of the calculated data from known elemental composition density and cross section information for the bulk material 70 Thermal n Time Profile Fit Decay Slope From Theory Hi S exp t t 1 T U Ave Macroscopic c Thermal n 2 Absorption E Cross section Ave Thermal n Time between PNG pulses Velocity Figure 41 Cartoon illustrating the comparison of the average macroscopic thermal neutron absorption cross sections from experimental and calculated data We calculated the theoretical average macroscopic thermal neutron absorption cross section 24 from ACTLabs elemental assay composition of samples of the granite the basalt and the CII carbonaceous chondrite meteorite the known material bulk density and known thermal neutron microscopic absorption cross sections using the equations in Figure 7 total elems C p N i elem bulk A Z V No and N en wia a E P fe elem i elem Figure 42 Equations used to calculate the theoretical average macroscopic thermal neutron absorption cross section for bulk materials 69 The macroscopic thermal neutron absorption cross section was determined
131. ither the Lynx web based interface or the Genie 2000 software package 64 both available from Canberra Industries Although the Lynx DSA hardware offers the required TLIST mode neither of these software options provides the flexibility and all of the capabilities we need for our specific instrument application The MultiScan software designed specifically for our project allows us to 1 acquire data in TLIST mode while synchronized to the PNG pulse 2 save data in ASCII format 3 analyze TLIST data for an unlimited number of 36 time windows and 4 perform multiple consecutive data acquisitions while maintaining the Lynx graphical analysis and configuration features a b The Energy signal comes in here Connect the BNC cable from here to the detector signal output Connect SHV HV here for HPGe detector OQdQodoldot c x 200V PHA ACO SS SYNC CHGR ADV CHGR RDY EE SWEEP ADV CH AOV MCS ACO SS GATE 6P V01 GP 02 GP 103 MON OUT a Re i Connect the HV Connect the Inhibit Connect the preamplifier Shutdown HPGe HPGe detector cable power here using a cable Detector cable here to the TRP with a 9 pin D connector here to the HV Inhibit connector Inhibit connector 12V DC Power Connector Lynx does NOT have a ON OFF switch it is ON when the Computer Ethernet connector Connect the yellow power is plugged Ethernet cable from here to the Ethernet switch in and OFF when connected to the computer it is
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133. ivation Natural Radioactivity Energy 10MeV Energy 10MeV Energy 10MeV Energy 10MeV Figures 16 Timing Windows and Sample Spectra a Placement of timing windows relative to each PNG pulse b Examples of different spectral shapes seen in different timing windows Figure 16a is an illustration of the PNG fast neutron pulse train and the intra pulse location of the different timing windows needed to separate the gamma rays that result from the inelastic scattering thermal neutron capture delayed activation and natural radioactivity processes Figure 16b is an illustration of the differences in the resulting energy and intensity of the gamma ray lines and background for each of these separated spectra 41 TLIST Data Analysis Technique We use the MultiScan software with Lynx DSAs to acquire TLIST data for gamma ray and neutron detectors with the start of a data acquisition synchronized with the start of a PNG pulse Synchronization of the PNG and DSA clocks insures the accuracy of these event times over multi hour data acquisition runs Our basic post processing procedure for the individual event by event data files is to take the modulus of the absolute times for the detected events with respect to the known PNG pulse period to derive the time of each event relative to the neutron pulse The next step is to put all of the files for a given experiment on the same time base The result is a master data set of energies and relative event times tha
134. ivation of 5Si npp Si and 7 Al n yB Si in the capture window from the delayed activation of 5Si n pp Si and 7 Al n yB 5Si and in the delayed activation and natural activity window by the delayed activation of 8Si n pB Si and Aln yp Si The 1811 keV gamma ray line is produced in the inelastic window by Fe n n y and the delayed activation of Fe n pB Fe and Mn n yB Fe in the capture window by the delayed activation of Fe n pB Fe and gt Mn n yB Fe and in the delayed activation and natural activity window by the delayed activation of ein pp Fe and Mn n yB Fe The 1942 keV gamma ray line 1s produced in the inelastic scattering window by Ca n n y and in the capture window by Ca n 7 The 2203 keV gamma ray line is produced in the capture window and the delayed activation and natural activity window by the delayed activation of U Bi The 2211 keV gamma ray line is produced in the inelastic window by Al n ny The 2223 keV gamma ray line is produced in all three windows by H n y The 4438 keV gamma ray line is produced in the inelastic window by C n n y and lO n n a C Finally the 6129 keV gamma ray line is produced in the inelastic window by l O n n y and O n pB O and in the capture window and the delayed activation and natural activity window by the delayed activation of O n pB O Table 7 lists the intensities and uncertainties of the gamma ray lines analyzed and th
135. ix Windows and OS X parallel with MPI MCNPXKX is the next evolution in a series of Monte Carlo radiation transport codes based as a superset of MCNPAC developed nearly sixty years ago and still maintained at Los Alamos National Laboratory The Monte Carlo Neutral Particles code MCNP the precursor to MCNPX is the internationally recognized Monte Carlo code for analyzing the transport of neutrons gamma rays electrons both primary source electrons and 72 gamma ray interactions producing secondary electrons and coupled transport e g secondary gamma ray transport resulting from neutron interactions Geometry and VISED MCNPX is a three dimensional Monte Carlo computer model in which the user can model neutron gamma ray and X ray transport using defined cross sections libraries provided in the code in a virtually defined environment The user can specify in an input deck a source detector objects and their geometries material specifications and elemental compositions as wells as the desired flux tally outputs for defined objects Input decks were created using the Visual Editor VISED 70 created by Randy Schwarz is an interactive graphical user interface tool that makes it easier to create and display objects geometries materials transformation sources and tally plots and the input deck to run using MCNPX Configurations Modeled and Approximations That Were Made I used the MCNPX Visual Editor Version A 24E t
136. kes advantage of four different gamma ray producing processes inelastic scattering neutron capture neutron activation and natural radioactivity to determine the elemental abundance of the planetary material Since the energy spectrum of the gamma rays given off following excitation by fast or thermal neutrons is a superposition of the characteristic lines of the isotopes of the various elements present all the major constituents of soil and rock can be identified by these neutron induced gamma ray emissions In addition measurements of the neutrons emerging from the surface will be particularly sensitive to the hydrogen carbon and oxygen content of the subsurface material and thus neutron detectors make excellent instruments for the detection of H water ice or frozen CO to depths of about 50 cm It 14 is the union of all three components PNG gamma ray spectrometer and neutron detectors that makes PING such a powerful approach Gamma Ray Spectroscopy Converting the measured gamma ray spectral data to elemental abundances begins with evaluating the peak areas of the many gamma ray lines of interest although the actual analysis process may be spectrometer dependent High Purity Germanium HPGe detectors provide the best energy resolution so that simple peak fitting techniques may be used However even the HPGe spectral analysis process may become complicated due to the presence of interfering lines 52 Peak fitting 1s al
137. l and PNG source point on top of the granite basalt and asteroid layering simulant configurations 74 Experimental thermal neutron dieaway results and fit for the granite 91 xli LIST OF FIGURES CONT FIGURE eegene eege PAGE 45 Experimental thermal neutron dieaway results and fit for the basalt 02 46 Experimental thermal neutron dieaway results and fit for the asteroid simulant 92 47 Image of the PING instrument prototype on top of the Concord Grey Granite e EE 120 48 Image of the PING instrument prototype on top of the Columbia River Basalt monuement takenonm05 2 1 20 eet 121 49 Schematic of the Columbia River Basalt monument dimensions 121 50 Sketch of the PING equipment spacing used for all experiments 122 51 Notes from the basalt monument PING experiment sssseeeeeee 122 52 Image of the PING instrument on the layered asteroid simulant 123 xiii ACTLabs ASCII C complex CT1 CM CNF C type DAN D D DSA D T FWHM FWTM GGAO GRC GRS GSFC HDPE HPGe LRO MESSENGER MCNP MCNPX MPI MSL NASA NCCS NEAR NEAR Shoemaker NIR NS PHA PING PNG PTC Q value TLIST UV VIS VISED XRS LIST OF ABBREVIATIONS Activation Laboratories located 1n Ontario Canada American Standard Code for Information Interchange Carbonaceous asteroid spectral t
138. lTLTOO2 log pdf 110821He1TLT003 log pdf 110822He1TLT003 log pdf 110822He1TLT005 log pdf 110822He1TLT006 log pdf 110822He1TLT007 log pdf e 110821He2TLT002 log pdf 110821He2TLT003 log pdf 110822He2TLT003 log pdf 110822He2TLT005 log pdf 110822He2TLT006 log pdf 110822He2TLTO007 log pdf Asteroid The available data for the Asteroid configuration 1s as follows e 110823Gel TLTOOI log pdf 110823Gel TLTOOI Capture filtered pdf 110823Gel TLTOOI DANA filtered pdf 110823Gel TLTOOI Inelastic filtered pdf e 110823Gel TLTOO2 log pdf 110823Gel TLTOO2 Capture filtered pdf 110823Gel TLTOO2 DANA filtered pdf 110823GelTL TO0O2 Inelastic filtered pdf e 10824Gel TLTOOI log pdf 110824Gel TLT0OI Capture filtered pdf 110824Gel TLTOOI DANA filtered pdf 110824Gel TL TOOI Inelastic filtered pdf e 10824Gel TLTOO2 log pdf 110824Gel TLT002 Capture filtered pdf 110824Gel TLTOO2 DANA filtered pdf 110824Ge1TLTO02 Inelastic filtered pdf e 10824Gel TLTOO3 log pdf 110824Gel TLT003 Capture filtered pdf 110824Gel TLTOO3 DANA filtered pdf 110824Gel TL T003 Inelastic filtered pdf e 10824Gel TLTOOA log pdf 110824Gel TLT0O04 Capture filtered pdf 110824Gel TLTOOA DANA filtered pdf 110824Gel TL TOOA Inelastic filtered pdf 112 110824Gel TLTOO5 log pdf 110824Gel TLTO0O5 Capture filtered pdf 110824Gel TLTOOS DANA filtered pdf 110824Gel TL TOOS5 Inelastic filtered pdf 110824Gel TLTOOO 1 log pdf 110824Gel TLTOOO 1 Capture filtered pd
139. ma ray line from carbon 4 439 MeV is in a very accessible part of the gamma ray spectrum Since there are manageable spectroscopy challenges in reducing noise from interfering lines and analyzing the Doppler broadening of the carbon peak to get the best sensitivity for carbon we have used techniques for detecting and optimizing the sensitivity to carbon to be able to distinguish carbonaceous asteroids from other classes of asteroids and this will aid in strengthening the connection between C complex asteroids and their carbonaceous chondrite meteoritic analogs Neutron Data Analysis Converting neutron count rates by looking at the time dependence following the pulsed of neutrons at a single location to geochemical information requires the use of the same type of Monte Carlo simulations as in the gamma ray analysis The transport of neutrons through soil depends on both scattering processes that reduce the neutron energies down to the thermal range 0 025 eV and the diffusion of these thermal neutrons throughout the soil until they are captured The most commonly used neutron detector is the He 3 proportional counter tube 57 Separation of the thermal and epithermal neutron count rates in He 3 tubes is easily accomplished using a two detector system where a thin Cd shield covers one of the detectors Since Cd has a very high cross section for neutrons below 0 4 eV the Cd shielded detector cannot detect the 16 thermal neutrons and produ
140. mposition of the subsurface material for any solid body in the Solar System even bodies with a dense atmosphere PING can measure a wide range of elements e g C H O P S Si Na Ca Ti Fe Al Cl Mg Mn K Th and U depending on their abundance in the planetary material Pulsed Neutron Generator The PING instrument uses a Thermo Scientific MP320 14 MeV Deuterium Tritium D T PNG 19 shown in Figure 8 During the experiments The PNG beam current high voltage frequency and duty factor were set to 60 uA 50 kV 1 kHz and 30 10 respectively At these settings the PNG produced a neutron pulse width pulse period energy and rate of 100 us 1000 us 14 MeV and 3 x 10 n s respectively One can think of neutron generators as compact particle accelerators where the neutron generation process for the Deuterium Deuterium D D or D T compact generators is a follows The deuterons are accelerated toward a light target nucleus containing deuterium or tritium an applied voltage difference of about 100 300 kV and interact with either the deuterium or tritium in the target material causing fusion to occur in Helium isotopes and the production of neutrons deuterium deuterium reaction H 4H He n Q 3 26 MeV deuterium tritium reaction H 3H He n Q 2 17 6 MeV where the resultant neutron beam energy is uniform since the Q values are significantly larger than the initial particle energy A PNG containing
141. n I0 30Z S I0 30e s 0 300 9 990 ZE 9 990 ZE T000 0 aasn ro 0 gt TO O YIM WI L0 389TEE T LC 3LE 61 39SI1S6 v t 5 078S T SO 3 446v7 LOTO 7I 000 0 umouxun 0 3 0 3 v0 300 8 LOTO ZT 8 ZOTO ZT 000 0 0 0 I0 0 KI WI L0 3787TO Z ECH 91 596 97 6 VC 3 07c8S T 80 3 SS8 S T68ZO 8EZ S0 d 8E 6 T uMouxun 0043484 0043484 S0 300 T68ZO 8EZ E T68ZO 8EZ S0 JE8E6E T ELEEEBES ET TO O wdd SW SN4 90 3S8977 T SECH LT4316 S9 T vC 3 078S T Z0 396 v0 T T8EO ZEZ S0 dZ90T p 7 uMouxun 00 30r Z 00 304 v0 300 T T8E0 ZEZ T T8E0 ZEZ S0 3 9T V Z 199999T1 v2 so o e ep 5iujeJ85 994S eAe wdd SW SN4 OT 3SS07T 9 9c 3 E 9T 3IZVS8 T vC 3 07c8S T 80 39 C T T 8 086 802 Sv200000 0 uMou xurn 20 30 Z0 J0 S0 300 2 8 086 80c Z 8 086 80Z S z00000 0 Sv c T O e ep D wWesad 9974S aAe wdd SW SN4 80 3S8TC t Sc 34 T LT 3ZVTISY C vC 3 078S8 T Z0 JES89S T c Z07 Sc 0000 0 uMouxun T0 307 I T0 30Z T T0 300 I ZC A0 1 e Zoz Sc 0000 0 SZ S eyep Jiwesad 3974S ang wdd SW SN4 80 JSE0 6 9 vc dv 9T 3v 8 0 C vC 3 078S T 80 3 P887 T1 E8E vOC 90 3E E E9 7 UMouxun 00 30b 00 30t v0 300 2 8 VOZ c ee8e voc 90 JEEEE9 Z ELEEELEEN Z so o e ep 21u1e485 aas AL wdd SW Snd L0 381960 Z 2 3S8 T 9T J90EET T vC 3 0788 T 60 32079T 4 v8 8T 90 3 991 T uMwouxun T0 3S8 T TO 4S8 T Z0 300 T v8 8T WON 90 3 99T T L999999TE T S O e ep owe 994S SAe
142. n type Ortec GMX Series HPGe portable coaxial detector system crystal diameter 53 2 mm and crystal length 69 5 mm in the bare and enclosed in a borated rubber cap to reduce the effects of fast neutron damage of the Ge crystal configurations 32 was used to acquire gamma ray data The HPGe semiconductor gamma ray detector 1s attached to a portable liquid nitrogen dewar that cools the detector down to 77 K The HPGe detector used has the following specifications as originally specified and or measured by the Ortec manufacturer 1 detector model number GMX30 76 A PL 2 serial number 49 N22577A 3 cryostat configuration CFC GG 76 4 dewar model DWR 5 0G 5 dewar capacity 5 liters 6 detector cool down time 6 hours 7 static holding time 3 days 8 preamplifier model A232N 9 H V filter model 138EMI 10 H V filter serial number 9198922 11 high voltage bias 3500 Volts 3000 Volts after HPGe was repaired by the manufacturer and returned in August 2012 12 resolution Full Width at Half Maxium FWHM at 1 33 MeV Co 1 8 keV amplifier shaping time of 6 us 13 peak to Compton ratio Co 63 1 amplifier shaping time of 6 us 14 relative efficiency at 1 33 MeV Co 30 amplifier shaping time of 6 us and 15 peak shape FWHM Full Width at Tenth Maximum FWTM Co 2 4 amplifier shaping time of 6 us Figure 13 shows a schematic cross section of an n type coaxial detector p electrode n electrode Figure 13
143. ndows allows us to obtain the most statistically precise measure of the delayed activity so that we can retain the best possible precision for the net peak counts while substantially improving on the accuracy of the measured elemental concentration Once the counts in a peak are known to only be due to a single element and type of reaction MCNPX calculations can accurately relate the counts to elemental concentration It is also worth noting that the half lives of the delayed activations are typically at least 1000 times longer than the neutron period so they can be considered to be constant during the neutron generator pulse period as assumed in the above analysis eliminating the need to even correct for the half lives Identifying and Removing Sources of Systematic Error Using TLIST data When working with a weak constant neutron source e g from GCRs there is no need to record event by event time and energy data if the data are transferred periodically with reasonable frequency since each chunk of transferred data can be separately analyzed to identify a problem with the instrument e g deteriorated resolution and removed without compromising the entire concatenated data set However it is still difficult to determine if the collected data have been compromised due to other errors These difficulties can be mitigated for the case of in situ gamma ray and neutron spectroscopy measurements with the PING instrument since it takes advantage of
144. ng Procedure GSFC Form 23 6l Section 7 for Docket 709 0139 This includes posting radiation hazard signs along the test site 250 foot keep out perimeter doing a gamma ray and neutron radiation survey and having a spotter located outside Building 206 to insure that no one enters the keep out zone during PNG operations Insure that the PNG controller computer is located a safe distance from the PNG with appropriate shielding For our purposes the computer is located at GGAO in Building 206 at a safe distance from the PNG when it is being operated on the granite monument at our test facility Insure that you have uncovered the granite or basalt monument run all necessary cables from Building 206 to the monument and brought out all necessary equipment for the experiment Place the PNG on top of the monument Connect the cables to the PNG a Insure that the RESERVOIR J1 SOURCE J2 HV SIGNAL J3 and HVPS J4 cables are connected All of the PNG connector cables are unique and cannot be inadvertently interchanged Figure 1 a Electronics Connector End View b Source amp Reservoir End View PNG Operations Manual 02 02 2011 Page 3 of 11 135 b POWER CABLE Plug the AC power cable into the AC POWER connector on the PNG electronics enclosure Figure 2 AC Power Connector c INTERLOCK CABLE The 300 foot gray interlock cable must be connected to the INTERLOCK connector on the PNG electronics enclosure and the HVPS disable
145. ng it into a state where it is ready to produce neutrons Turn the key back turn counter clockwise to disable the system Exercise caution as the PNG could produce neutrons with a single command from the PNG software GUI if the HVPS disable box interlock button is not pushed down It is recommended that the key is in the disable position while personnel are setting up If the RED LED is illuminated than the PNG is most likely making neutrons and no personnel should be near the PNG If you are near the PNG and the red LED illuminates immediately push down the large red button to turn off power to the PNG PNG Operations Manual 02 02 2011 Page 7 of 11 139 Pulsed Neutron Generator Setup 1 Open the PNG Graphical User Interface GUI a Start the GUI by double clicking on the DNCII icon located on the Windows Start tab or the DNCII short cut on the Desktop If you are having problems finding the DNCII exe program it should be located on the installation directory CADNCII on the computer At this point the main interface screen shown in Figure 9 should be displayed ma DN fe fx Fie Screen Abo Beam Current pA 0 3 High Voltage kV X 0 Getter Current A 1 15 50 0 50 100 150 2 00 0 0 0 mem ad uu E Beam Cunent h Mo 0 75 100 25 0 75 0 i e 125 Pulser Internal E M 25 SN 10000 Hz Do Moisal 0 0 100 0 Ge 160 150 ei E 450 0 State Totalizer EN Beam Control HV Control DE
146. nite 86 14 Gamma ray element Si experimental and MCNPX ratios for the basalt 87 15 Gamma ray element Si experimental and MCNPX ratios for the asteroid SEET 89 16 The calculated macroscopic thermal neutron absoption cross section calculations for the granite THODLUPBDOTIL teuer Segen EE a 93 17 The calculated macroscopic thermal neutron absoption cross section calculations for Cine Dasdi MONN M tee 94 18 The calculated macroscopic thermal neutron absoption cross section calculations for Me aerO Sr db ai ee 95 19 Granite basalt and asteroid simulant calculated and experimental macroscopic thermal neutron absorption comparison Note the asteroid simulant calculated value is based upon CII carbonaceous chondrite calculations esesssseeeeeesssssssseersssssssese 96 20 ActLabs columbia river basalt elemental assay ccccccccccccesssseseeeeeeeeeeaeeesseeeeeees 105 21 ActLabs concord grey granite elemental assay 106 22 Raw TLIST gamma ray thermal and epithermal neutron data collection totals for data acquired with PING on the 10 experimental rock configurations Hel and He2 refer to the He thermal and epithermal neutron detectors UT stands for the detectors borrowed from the University of Tennessee and Navy stands for the detector borrowed through Stan Hunter from the Navy seeeessssssssseenssssssssseerrssss 107 1X LIST OF FIGURES SIG B rdc
147. nt ssssses 26 Graphs of the MCNPX computer modeling results of the epithermal and thermal neutron flux distribution as a function of neutron penetration depth for the C type asteroid blue and the basalt layering asteroid simulant red 21 Drawing of the spacing of the PING components using for each experimental EIERE C8 RN NE TE NODE ES 20 E ET ER eC T 3l A picture of a Cockroft Walton neutron generator eesesessseoeerssssssssscerrssssssseeeeees 32 LIST OF FIGURES CONT SIG B rdc PAGE 13 Schematic of the cross section perpendicular to the cylindrical axis of the n type LIP GE OOIe OP OE SA EE 33 14 Schematic of a He neutron POS CLS CLOE EE 36 15 Lynx DSA Images of a the front and b the back showing connection ports for 16 17 18 19 20 2L 22 23 24 25 26 21 28 HPGe Or tlie acquisition Syster E 37 Timing Windows and Sample Spectra a Placement of timing windows relative to each PNG pulse b Examples of different spectral shapes seen in different timing EH 4 Spectra from Different Time Windows Gamma ray spectra from a 6 33 hr acquisition using a HPGe detector on top of Columbia River basalt 43 Figure 18 Spectral Feature and Time Distribution a A portion of the non time sliced 6 33 hr gamma ray energy histogram fr
148. o create the two input scripts each for the granite monument basalt monument and asteroid simulant configuration input files The first input script for each of the three configurations described the geometries physical dimensions of the objects in the model including the PNG HPGe detector and the basalt granite or asteroid monuments material definitions e g ActLabs elemental assay of basalt granite or asteroid simulant composition HPGe detector crystal and other objects importances e g neutron and or photon importance for each object in the computer simulation the PNG neutron source HPGe detector and the F2 73 output surface tally units particle cm normalized to one input particle e g photons cm neutron for the HPGe detector crystal surface These models simulated 14 MeV neutrons generated from the PNG which was set a point source without any housing from 0 100 us neutron transport from the PNG and resultant generation of gamma rays produced from neutron nuclei interactions in the probed material configuration e g basalt monument granite monument or asteroid simulant layered configuration and air and the resulting gamma rays that reached the surface of the HPGe detector HPGe bare crystal only no housing Figures 8 shows the geometry and spacing of the PNG point source and HPGe crystal on each of the material configurations 182 9 cm 182 9 cm
149. o insure that the neutrons from the PNG were only interacting with the granite or basalt itself Meter sized Asteroid Analog In order to optimize PING for an asteroid lander we need to test PING on a known and well characterized meter sized test sample or simulant Ideally one would use 3 m of primitive carbonaceous chondrite meteorites analogs to C type asteroids However there are only 9 of the most primitive carbonaceous chondrite meteorites on Earth a total amount of approximately 21 kg so it was necessary to construct an asteroid simulant It was required that an appropriate asteroid simulant must have nearly the same neutron response as the C type asteroid The asteroid simulant must have an equivalent 24 neutron spatial distribution within the volume similar neutron moderation properties and equivalent neutron absorption processes similar average macroscopic neutron absorption cross section as that of a C type asteroid In addition the asteroid simulant must be isolated from human traffic to prevent interference from structures or even soil and flora which can be achieved by using our outdoor planetary neutron and gamma ray instrumentation testing facility To meet these requirements an asteroid simulant was constructed using 16 alternating layers of Columbia River basalt and high density polyethylene HDPE on top of a Columbia River basalt monument located at our testing facility Figure 8 shows the set up of the PIN
150. om PING data taken on the bare basalt monument b Time histogram showing how one can get better precision on the net peak area of each line shown in Table 2 by analyzing their respective energy histograms during different time slices during the PNG pulse period 46 Image of the Data and Load Waves menu files in Igor eseeeeessssss 54 Image of the Load General Text window ccccccccccccesssseseecceeeceeaeeneeeeeceeeeeeaeeeeees 55 Image of the Loading General Text window esses 55 ee he Grama MENi ee N E N bog H vabe n CUpd dot EUER 56 Image of the Fit Gauss With Tail window eeeeeeeeseeeeeeeeeenm mee 27 Fit Gauss With Tail gamma ray spectrum window eeeeeeeeeeeeeeeeeeeennnn 58 Acad Peak Type WNUN ee ee eege 58 Peak parameter values for the new peak added in the Fit Gauss With Tail panel 59 Selecting the Fit All button the Fit Gauss With Tail spectrum graph 00000eeeessess 60 Setting all of the peak parameters to Fixed eeeeeeeesssseeseeeernnnnneeeeeenen 60 Xl LIST OF FIGURES CONT FIGURE eegene PAGE 29 Image of the Compact Parameter Report window cccccccccsssseeeeeeeeeeceaeesseeeeeees 6l 30 Example of a MS Excel file with the copied report esssesssssoeeessssssssseeressssssseeeeres 6l ol Imasee or Windows Panel tM ISO 52 e IRE DURER NIS S deta dabiaactuseesi e
151. on generator to probe a meter radius area and down up to a meter into the subsurface 977 regolith PING s neutron and gamma ray spectrometers detect the resultant moderated neutrons and gamma rays that reach the surface The data collected are then analyzed and used to determine the bulk properties and composition of the regolith material probed A Monte Carlo model has also been established and benchmarked to be able to calculate the detector responses under a wide range of conditions Comparisons of PING experimental results to the Monte Carlo computer simulations and independently verified monument element assays show that more comprehensive MCNPX models are needed to properly model PING experiments in detail However we have shown that PING 1s capable of quantitatively determining the bulk properties of asteroids aiding in differentiating between different types of asteroids and strengthening their connection to meteorites The current MCNPX model is in excellent agreement with the experimental neutron responses but the detailed gamma ray count rates for a number of elements need more accurate modeling of the experimental instrumentation In one or two cases further investigation of possible sources of the production of specific gamma rays from competing elements and reactions will be necessary to get agreement between measured concentrations from specific gamma rays and the concentrations obtained from the laboratory determined assays of t
152. onstrate that one can distinguish between and separate interfering lines by nuclear process to improve both the peak identification and the measurement precision 45 27 Al n n y Doppler Broadened Moin pa SE Doppler Broadened Counts 2160 2180 2200 2220 2240 2260 2280keV Energy keV b 10000 Al n n Doppler Broadened H n y 1000 100 sch e Count Rate cts 10 usec 0 50 100 150 200 250 300 350 400 Time usec Figure 18 Spectral Feature and Time Distribution a A portion of the non time sliced 6 33 hr gamma ray energy histogram from PING data taken on the bare basalt monument b Time histogram showing how one can get better precision on the net peak area of each line shown in Table 2 by analyzing their respective energy histograms during different time slices during the PNG pulse period Improved Gamma Ray Measurement Precision By reducing the background separating a gamma ray spectrum by nuclear process improves the overall gamma ray line measurement precision As seen in Table 3 46 listing the total number of peak counts in an energy peak for different time windows many of the time gated inelastic scattering and capture lines show improved precision as compared with the same lines in the summed spectrum The 3539 and 4934 keV 5 Sin y capture lines show improved precision resulting from time gated analysis The precision of these S1 lines in the summed spectrum rep
153. ould be explained by the distance from the PNG to the HPGe detector as mentioned in the Table 13 discussion The C S1 and O Si experimental and MCNPX ratios are in fairly good agreement with one another and differ on average by a factor approximately 0 6 However Fe Si experimental and MCNPX ratios are in very poor agreement with each other and differ by a factor of 76 6 The poor agreement 89 can be due to the fact that the experimental ratios take into account everything in the experiment while the MCNPX model was constructed with only a point source for the PNG and a HPGe crystal for the HPGe detector at approximately the correct distance and location from the PNG The model did not include the HPGe detector housing and dewar the PNG housing or either of the neutron detectors and the locations of the detectors and PNG where at the approximate locations on the granite monument The absence of these pieces of equipment could explain the low value of the Fe Si ratios since the PNG housing and HPGe housing and dewar contained a great deal of Al and some steel contains Fe It is important to note overall that there is essentially no C present in the pure granite and basalt monuments therefore the experimental and MCNPX ratios are really due to the O n n a reaction Since the same amount or somewhat less because of no O in the high density polyethylene amount of oxygen should come from the asteroid simulant the significant increase in the
154. p7t dv6cve t 60 3 688 6 v6 S6 Z6000000 0 uMouxun 00 3S59 Z 00 3S9 2 Z0 400 T v6 S6 I v6 S6 26000000 0 c6 0 wdd Se ow ev 60 3vP4SST v VC 3ST T ST 369 T9 Vc 3v6cvE T 60 388069 7 8 906 26 SZ000000 0 umouxun 00 3ST T 00 3ST T S0 300 c 8 906 26 c 8 906 26 Sc000000 0 SCH wdd ON Ty 80 3 TZ90 T Sz 3S8 T 9T JTETHZ S VC 3V6CvE T 80 36TS Z v ZZ T6 6 00000 0 uMouxun T0 3s8 T T0 3s8 T 0 300 2 vec T6 ec ree T6 6 00000 0 6 E wdd SC DE Ov 80 4Z9TO E vc 38 T 9T 3Tv9SsE 7 Vtc 3v6cvE T 80 379vS T S8S06 88 9S8100000 0 uMou xun 00 38c T 00 38c T S0 300 c S98S06 88 c s8s06 88 9S100000 0 oer wdd A 6 L0 3C8 SE T Z JTZ T LT 3988TT T Vtc 3v6cvEe T 80 dEVTEE 8 79 28 00000 0 uMou xurn 00 3TC T 00 3TC T 0 300 T c9 8 1 z9 Z8 400000 0 EL wdd m JS 8 80 39T T ScC 3 9T 3Vv6ET9 Vvc 3v6cvE tT 80 3 0169 c7 849v S8 200000 0 uMou xun I0 307 I0 307 V0 300 8 9v G8 829v s8 200000 0 EZ wdd qu ZE Z0 470000 r vc 38 9 9T 3T1vC88 S vtc 3V6CcvE T 80 39208 v v06 64 S 00000 0 uMou xurn 00 3089 00 308 9 0 300 T v06 6Z T1 v06 64 S 00000 0 S E wdd 1g GE 90 3288 T v 2c 34T T LTc 3V9T S E Vvc 3V6cvE T LO 4ZS6S9 96 84 TZ0000 0 uMouxun TO SLT T TO SZT T Z0 400 96 8Z 96 8Z TZ0000 0 TZ wdd es vE 40 36SZv T vc 3 v 9T 3S09TE vc 3v6cvEe T 80 3s7C69p C 9TC6 v4 S8T00000 0 uMou xurn 00 30 t 00 30 t S0 300 c 9T26 v4 c o9Tz6 v
155. periments The gas proportional epithermal and thermal neutron detectors were used to measure neutrons detected as a function of time during the PNG pulse period to observe the epithermal and thermal neutron dieaway to determine the H content and thermal macroscopic neutron absorption properties of the bulk material The A He detector borrowed from Stan Hunter through the Navy was also used to collect data for the PING experiments but due to cable connection problems the data was deemed unreliable and therefore was not analyzed 34 basic bare He thermal neutron detector is a gas proportional counter consisting of a pressure vessel containing pressurized He gas and electrodes with an applied potential used to move charge within the gas for detection The detector includes a fine high voltage anode wire that has a strong electrostatic field that causes electrons to drift quickly to the anode and the positive heavy ions to drift to the cathode As the accelerated electrons approach the anode they have energies sufficient enough to ionize more gas This causes the electrons to participate in a Townsend avalanche which multiplies the electron charge bay a factor of 10 and remain localized along the wire near the event This event causes the detector which acts as a capacitor to discharge shghtly and the connected electronics record the resulting electrical pulse with a pulse amplitude that is proportional to the number of charged parti
156. r a particular PING experiment and time window is done as follows specific command line details can be found in Appendix III 1 The counts column in each time slice spectrum is loaded into an Igor profile table and assigned a wave name that refers to the spectrum s date and file number i e s namel s name2 etc e Under the Data menu select Load Waves gt Load General Text Browse Waves Load Waves SL Save Waves gt Load Igor Binary Make Waves Load Igor Text Duplicate Waves Load Delimited Text Load Image Load General Binary File Load Excel File Packages Change Wave Scaling Redimension Waves Insert Points Delete Points Rotate Waves Unwrap Waves Kill Waves Rename Data Browser Packages Figure 19 Image of the Data and Load Waves menu files in Igor 54 e Load anew filtered gamma ray spectrum file from your computer 0 0 8 Looking for a general text file Looking for a general text file Enable Plain Text Files A T al ae L3 HPGeBoron_Capt A Gl FAVORITES 4PGeBoron_Capt H rj 2 1_GelBo 0 66hrs old YF Preview rforsythe EEN P 2 1 Ge1Bo Gonrs pup GENERAL INFO 4PGeBoron_Inel P 120226Ge filtered txt Name 128226Ge1TLTBE laa DESKTOP 120227Ge filtered txt Scan number A of 1 i irati 120227Ge filtered txt Filename C Documents and A SERA Eh A fi ge Settings qamma sDesktop x 120227Ge fil
157. r and Planetary Surface Analysis Final Report 26 Jul 1966 26 Mar 1967 Mobile Oil Corp Field Research Laboratory 120 p 42 Mills Jr W R Givens W W Neutron Die Away Experiment for Lunar and Planetary Surface Analysis Progress Report 3 Jul 1967 28 Jun 1969 Mobile Research and Development Corporation Field Research Laboratory 124 p 43 Mills Jr W R Allen L S Neutron Die Away Experiment for Lunar and Planetary Surface Analysis Final Report 1 Jun 1970 30 Nov 1971 Mobile Research and Development Corporation Field Research Laboratory 110 p 102 44 Hearst J R Neutron Logging in Partially Saturated Media 22 Apr 1974 Preprint for the International Seminar on Instruments and Systems for Measuring and Monitoring Water Quality and Quantity Chicago June 4 1974 24 p 45 Mandler J W Continued Development of the Combined pulsed neutron experiment CPNE for Lunar and Planetary Surfaces Final Report 15 Jun 1971 23 Sep 1972 IIT Research Institute 65 p 46 Givens W W Mills W R Caldwell R L 1970 Cyclic Activation Analysis Nucl Inst and Methods v 80 p 95 103 47 Caldwell R L Mills Jr W R Allen L S Bell P R Heath R L 1966 Combination Neutron Experiment for Remote Analysis Science vol 152 no 3721 p 451 465 48 Boynton W V Evans L G Reedy R C and Trombka J I 1993 Determination of Planetar
158. r next to the monument Figure 1 Electronics on top of a large container next to the monument PNG Operations Manual 02 02 2011 P age 4 of 8 128 ii Attach the Lynx DSA power cord between the Lynx 12V 1 0 A power connector and one of the power strips iii Attach a yellow Ethernet cable between the Lynx connector and one of the available Ethernet switch ports labeled numbers 1 through 7 4 Setup the Gamma Ray Detector s This section describes how to setup and connect LaBr LaClz and HPGe gamma ray detectors to a Lynx DSA a Connect a LaBrj LaCl4 gamma ray scintillation detector to a Lynx DSA i Locate the HV ENERGY and PREAMP connectors on the Lynx DSA The Lynx DSA shown in Figure 2 has several rear panel connectors of interest including a HV SHV connector a HV SHV connector a 9 pin female PREAMP connector a 12V DC Power connector for the Lynx AC power adapter and an Ethernet connector Connect SHV HV here for LaBr LaCl detector 999600000 c Du PHa aca sS SYNC HGR ADV CHGR ROY Q O OG Oo o o o 5 o icy SWEEP ADY up MCSACOSS Di 6P V01 Cu eru GH ZAN i d oi IT E e Bel L TRP INN 521 H R LIP The Energy signal comes in here Connect the preamplifier Connect the BNC cable from here power here using a cable to the detector signal output with a 9 pin D connector 12V DC Power Connector Lynx does NOT have a ON OFF switch it is ON when the Computer Ethernet conne
159. r o TO e ep 5iueJ85 994S ang wdd SW Snd L0 34S0T8 t 2 398 9 ST 38TE E Z vC 3 0c8S8 T 60 d6cSE 9 p 7898 70T S 000000 0 uMou ur T0 398 9 TO 39S 9 0 500 Z 7898 ZOT z z898 Z0T S 000000 0 aasn s 0 EN e ep 5iueJ85 994S ang wdd SW Snd 80 3196 8 ECK 91 396767 vPC 3 E078S T 80 359v80 7 v6 S6 z00000 0 uMou xun 00 3Ss9 7 00 3Ss9 7 Z0 300 T v6 S6 1 v6 s6 90 FEEELE Z EEEEEEEEE Z 4 e ep JJwesad oe3s ang wdd SW SN4 LO 3TI9 7 vc 3ST T LT 3EVOZ7 C vPC 3 078S T Z0 3PISEP T1 8 E906 76 SO JEEEEE T uMouxun 00 3ST T 00 4ST T S0 300 c 8 906 26 ec 8 906 c6 S0 dEEEEE T E EEEEE ET co e ep 5iueJ82 994S ang wdd SW SN4 L0 3SC 6S V Sc 3S8 I 8T 3v8C8v C VC 3 0c8S T 90 35698T vec 16 L9T VT000 0 umouxun I0 3S8 I I0 3S8 I 0 300 c vec 16 c vec 16 Dudel 1999991 rt I e ep D1weseo 9974S aa wdd SW Sn4 LO 3tV9T vc 38 1 LT 3Zv 06 VC 3 078S T Z0 3 7SE8 1 S8506 88 S0 d49TE 9 T uwouxun 00 482 T 00 482 T S0 300 c S8S06 88 Z S8506 88 S0 3 91 9 T 1999991 9T S O e ep D1wesed aale AL wdd SW SN4 90 JZT8SE T ERAN 8T 39v77T T vPC 3 078S T Z0 3 0S60 79 28 S0 4 99TZ 9 uwouxun 00 3I T 00 3I7 I Z0 300 T 79 28 1 z9 Z8 S0 3 99T7 9 1999999179 c e ep 2iu1e485 8935 SA amp wdd dOI Shd 90 3S0TZt Z ScC 3 L 8T 36 v89 9 vPC 3 078S T 90 3909 T P 829 S8 S SE 000 0 uMouxun T0 30Z7 I0 307 v0 300 8 9v S8 879v s8 S SE000 0 S ESE I eyep
160. re as well as the basic geochemistry of C type asteroids Knowing the concentration of these elements as well as subsurface features in these most primitive asteroids will help answer important questions about the early history of the Solar System its evolution and the formation of the Earth Table 1 Material Configurations for Each PING Experiment Material Configuration Description amp Purpose Monuments simulate planetary analogs with each Basalt or Granite having a total volume 1 8 Monument m x 1 8 m x 0 9 m Concord Grey Granite and Columbia River Basalt Monuments Layering configuration simulates a homogenous C type asteroid meteoritic CII chondrite analog with a total volume 1 8 m x 1 8 m x 1 4 m C type Asteroid Simulant Asteroid Simulant 3 configurations consisting of the C type asteroid simulant covered with 2 54 cm 3 08 cm and finally Subsurface Water Ice 5 62 cm of basalt layers Subsurface Ice on with volumes of 1 8 m x C type Asteroid 1 8 m x 1 4 m 1 8 m x 1 8 m x 1 7 m and 1 8 m x 1 8 m x 2 0 m 3 configurations consisting of layers of basalt and polyethylene on top of basalt monument where the top layer and then the top 2 layers of basalt are replace with granite Basalt amp Granite Substitution Layering Element Substitution 28 PING Experimental Equipment Set up on Rock Configurations The spacing dimensions of the components of the PING instrument HPGe He epith
161. rea and all of my graduate student cohorts at Fisk and Vanderbilt University including Ebonee Walker Deatrick Foster Desmond Campbell and Brittany Kamai Each member of my Dissertation Committee has provided me extensive personal and professional guidance and taught me a great deal about scientific research and life I would especially like to thank Dr Ann Parsons Dr Jeffrey Schweitzer and Dr Keivan Stassun As my teachers mentors and friends you have all taught me more than I could ever give any of you credit for here You have all shown me through your actions what a IN good scientist and person should be as well as provided me with a work environment in which I have been able to flourish both professionally and personally No one has been more important in my life to me in the pursuit of this project than my family I would like to thank my ultimate role models my parents and brother whose love guidance and strength are with me in whatever I chose to pursue I would also like to thank my cousin and aunt Kara and Lillian Kozla who have always been there to cheer me up and help me see the forest through the trees TABLE OF CONTENTS IDE KIL SEIS eec 111 ACKNOWLEDGMENTS EE 1V LIST E EE viii LIST OE TE RT X ETS OF ABBREVIATIONS E XIV LANTRODUC HON E I What do we know about asteroids eeeeseessssssssssseeeeeeee eene 4 What is the state of the asteroid to meteorite connection ssse 4
162. resenting results without time slicing is 8 3 and 16 9 These same Si lines show improved precision 7 3 and 9 2 in the thermal neutron capture spectrum obtained from the removal of the gamma ray background due to inelastic scattering A similar but somewhat smaller improvement is seen for the 2211 keV Al n n y inelastic line 47 Table 3 HPGe gamma ray line intensities Iy and uncertainties 0 during different time windows for a 6 33 hr PING acquisition on the bare Columbia River basalt monument For the 1779 and 6129 keV activation peaks the half lives are 2 3 min and 7 1 s respectively Note the Activation column includes data from all times that the neutron pulse was off Neutron thermalization begins even before the fast neutron pulse turns off at 100 us and it reaches a peak at approximately 100 us and then slowly decays therefore the H n y 2223 keV gamma ray line appears in both the inelastic scattering and thermal neutron capture windows due to the time windows selected for these processes Summed Inelastic Scattering Thermal Neutron cte E Data Window Capture Window mem Te ID lg s ID d 2 ID lg cts 96 cts 90 96 cts 90 PESE pes os seem e Dmm E ee 2223 1892 161 Hay oeilazlnwa 88 74 gt wp ep p p pepper Ge 115 4934 1472 16 9 Siy 92 0p An interesting situation is observed for the 1779 keV Si nn y and 6129 keV O n n y inelasti
163. rved during the neutron generator pulse gamma rays produced by thermal neutron capture observed during the interpulse period and gamma rays from delayed activation and natural radioactivity observed towards the end of an interpulse period thus reducing background and line interference in these three separate spectra In addition a pulsed neutron source also allows for epithermal and thermal neutron die away measurements where the build up and decay of the epithermal neutron signal during and immediately following the neutron pulse may be used to infer the hydrogen content of surface and subsurface materials and the decay of the thermal neutron signal following each pulse may be used to infer the macroscopic thermal neutron absorption cross section of the bulk material 29 Orbital gamma ray instruments must depend on the GCR particle flux as the excitation source for gamma rays Using the GCR excitation source requires complex modeling of the interaction of the GCR high energy protons and higher Z elements with the regolith to produce a cascade of particles and eventually a neutron flux of about 13 n cm s rather than the isotropic 3000 n cm s available with a PNG Variations of the temporal and energy spectral characteristics of the GCR are typically accounted for by normalizing the measurements over a large spatial area where the composition does not change with time which 1s difficult on a planetary surface For example the NASA N
164. sensing techniques on the microscopic and macroscopic level What Possible n Situ Measurement Techniques Can Be Used to Obtain the C complex Asteroid Bulk Geochemistry In Situ Measurements Non destructive in situ neutron gamma ray analysis techniques have been used for decades in both the oil industry and for earth science research to determine such things as the bulk elemental composition porosity and density of materials 31 We 10 have developed and tested a prototype instrument named PING Probing n situ with Neutrons and Gamma rays 32 that leverages these well established techniques to measure the bulk subsurface hydrogen content and elemental composition of an asteroid without the need to drill below the surface These measurements can be used to transform the elemental concentration data into mineralogy data which can then be used to derive the bulk physical properties of the asteroid material PING can measure the abundance of nearly all important rock forming elements and volatiles e g C H O P S Si Na Ca Ti Fe Al Cl Mg Mn K Th and U depending on their abundance in the planetary material down to a depth of 50 cm thus making it ideally suited to determine the subsurface bulk composition of C complex asteroids The PING instrument as shown in Figure 3 uses a PNG to irradiate an asteroid with fast neutrons that stimulate the nuclei of the asteroid material beneath the instrument down to 50 cm below the surfa
165. sion cable to HPGe HV Shutdown connector and connect the other end of the extension cable to the HV INH connector on Lynx 3 Connect a skinny BNC extension cable to the HPGe Inhibit BNC cable and connect the other end of the cable to the TRP INH connector on Lynx PNG Operations Manual 02 02 2011 P age 7 of 8 131 5 Setup Lynx to PNG connections for PNG synchronized data acquisitions This section describes the additional connections that to be made between the Lynx DSA and the PNG for PNG synchronized experiments a Connect the Lynx DSA to the PNG for PHA Coincidence Acquisitions i Locate the Lynx GATE and the PNG Source Pulse BNC connectors These connectors can be found on the back of a Lynx box and the PNG front electronics ii Connect a BNC cable between the Lynx GATE and the PNG Source Pulse BNC connectors b Connect the Lynx DSA to the PNG for TLIST Acquisitions i Locate the Lynx SYNC and the PNG Source Pulse BNC connectors These connectors can be found on the back of a Lynx box and the PNG front electronics ii Connect a BNC cable between the Lynx SYNC and the PNG Source Pulse BNC connectors 6 Setup for multiple time gate PHA Coincidence Acquisitions This section describes how to setup for PNG synchronized Lynx PHA coincidence acquisitions using a HPGe detector and two 2 Lynx boxes a Connect the HPGe detector to a Lynx DSA as explained in section 4b on page 7 of this manual b Connect a BNC
166. so possible for scintillation spectrometers but the broader energy resolution may make peak identification and analysis more difficult To reproduce the measured spectra it is frequently necessary to develop a library of spectrometer response functions for each element likely to contribute 53 54 While the strength of the gamma ray lines depends on the concentration of the isotope of the element that produces the line the line strength except for the case of natural radioactivity also depends on other factors such as the water content and the presence of other neutron absorbing isotopes in the material Monte Carlo modeling is needed to take into account the complex ways in which the neutrons interact in planetary surface materials and affect gamma ray line production 55 Converting gamma ray spectra to elemental abundances is thus an iterative process where the material composition is adjusted until the predicted line fluxes match the measurements This forward modeling process is a standard technique and was used successfully to analyze gamma ray spectra from Mars Odyssey s Gamma Ray Spectrometer 56 15 A scientifically crucial capability of PING is its ability to detect subsurface carbon Knowing the concentration of carbon in comparison to the other major elements in primitive asteroids can be the key to understanding the initial composition of planets in our solar system and the basis for their subsequent geochemical evolution The gam
167. st The destination Y wave will be set by Interpolate2 to the same number of points as the destination X wave Table 5 shows the single energy calibration for the Basalt Granite and Asteroid Simulant configurations below 66 Table 5 Energy Calibrations for Summed Time Sliced Granite Basalt and Asteroid Simulant Configurations Data using HPGe Bare and Boron Wrapped Detector Bare Asteroid Inelastic Bare Asteroid Capture Bare Asteroid Delayed Activation amp Natural Activity Boron Asteroid Inelastic Boron Asteroid Capture Boron Asteroid Delayed Activation amp Natural Activity Granite Inelastic Granite Capture Granite Delayed Activation amp Natural Activity Basalt Inelastic Basalt Capture Basalt Delayed Activation amp Natural Activity Energy Scale 120329Ge1TLT001 2 inelastic filtered txt Equation 0 9513 2 4441 p Energy Scale 120329Ge1TLT001 2 capture filtered txt Equation 0 4590442 4441 p Energy Scale 120329Ge1TLT001 2 DANA filtered txt Equation 0 52955 2 4439 p Energy Scale 110824Ge1TLT003 inelastic filtered txt Equation 0 20147 3 0533 p Energy Scale 110824Ge1TLT003 capture filtered txt Equation 0 25758 3 0531 p Energy Scale 110824Ge1TLT003 DANA filtered txt Equation 0 03963 3 0534 p Energy Scale 121102Ge1TL T001 1 inelastic filtered txt Equation 0 54144 2 4542 p Energy Scale 121102Ge1TLT001 1 capture filtered txt Equation 0 41936 2 454
168. t can be sliced in any number of ways Slicing the data in time means establishing the boundary between times where different nuclear processes dominate The result is separate gamma ray spectra for the specific processes that have the event statistics characteristic of the total acquisition time Slicing the data in energy means establishing energy boundaries around spectral features whose time profile one wishes to study After generating this master data set with energy and relative time values we can analyze our gamma ray and neutron data to infer the bulk elemental composition density and subsurface layering of planetary bodies Gamma ray line identification problems can be lessened with the PING instrument by taking advantage of the pulsed nature of the in situ neutron source synchronized with the data acquisition system particularly if the neighboring energies originate from reactions having different time delays relative to the production of the neutron Naturally different reactions that occur at the same time such as prompt n n 42 n p and n a reactions that all require high energy neutrons cannot be separated from each other by selecting different analysis times Counts Summed Spectrum Inelastic Spectrum Capture Spectrum Delayed Natural Activities Spectrum 0 2000 4000 6000 8000 Energy keV Figure 17 Spectra from Different Time Windows Gamma ray spectra from a 6 33 hr acquisition using a
169. tains two gamma ray lines at slightly different energies They are grouped together because under many circumstances they cannot be separated Table 2 y ray lines to analyze for inelastic Y ray spectra time window optimization Possible Sources of Neutron Nuclei Interactions Gamma Ray Lines keV A n ny Al Fe n n y Ge Re n p Mn D te Mg n y Mg p Al Mn n y Mn B Te SSi n ny Si 5Si n p AI B Si Al n y AI B Si Ee n n y 6o 160 n p IN B 8O E mo E on gt 44 Problems with interfering lines can be dealt with by examining the time profile of the individual gamma ray lines Figure 18a is an example of a 6 33 hr summed HPGe gamma ray spectrum taken with PING instrument on top of the basalt monument In this spectrum there are many gamma ray lines that are clearly interfering with one another such as the Doppler broadened Al n n y H n y Na SE the Doppler broadened Mfe n n y and the Si n n y One way to distinguish Al n n y and the H n y gamma ray lines is by plotting the net peak area of the unresolved spectral feature in Figure 18a as a function of time as shown in Figure 18b to distinguish which line is present Figure 18b shows the time histograms of the net peak areas for the 2211 keV 7Al n n y and the 2223 keV H n y gamma ray lines The time histograms are the gamma ray count rates per 10 us time interval and dem
170. te Service Pack 1 Analyzing MCNPX Output The gamma ray net peak areas and uncertainties for F2 and ba tallies are determined by analyzing the data in the same way that experimental gamma ray data is analyzed in the Gamma Ray Peak Fitting Using the Fit Gauss with Tail Igor Pro Function section of this chapter Once the net peak areas and uncertainties are determined for the F2 and FS tallies the detector efficiency for a gamma ray peak energy is calculated by taking the ratio of the F8 tally F2 tally net peak areas and the uncertainty is calculated by taking the square root of the sum of the square of the uncertainties It is useful to note that the F8 tally gamma ray spectra only include inelastic scattering and thermal neutron capture gamma rays since MCNPX does not calculate gamma rays from natural radioactivity or delayed activation 75 CHAPTER IV RESULTS AND INTERPRETATION Some of the gamma ray results presented in this chapter will appear in the peer reviewed publication Parsons A Bodnarik J Evans L Nowicki S Schweitzer J Starr R Subsurface In Situ Elemental Composition Measurements with PING Proceedings of the 2013 IEEE Aerospace Conference in press Some of the neutron results presented in this chapter are from the peer reviewed publication J G Bodnarik J S Schweitzer A M Parsons L G Evans and R D Starr PING Gamma Ray and Neutron Measurements of a Meter Scale Carbonaceous Asteroid Analog
171. tered txt 281282 N26 128226Ge1TLTBBT Pictures 120228Ge filtered txt tlist txt RE ET EE ita Time started Februarv 26 o Downloads e e ee DL B3 21 46 PH 120228Ge filtered txt Time finished February 26 SHARED 120228Ge filtered txt 28012 86 82 14 PM L EPSON Workt 120301Ge filtered xt Aquisition mode Tlist L 2 gs66 bluearrow 120301Ge filtered txt Name 120226Ge1TLTOOL ca 12n3n16e filtered tet ature filtered twt Cancel Open Figure 20 Image of the Load General Text window e Skip the first two columns and name the last column as seen above Loading General Text CHANNEL ENERGY COUNTS B 4 99 72 1 2 53 8 2 B BB 24 3 2 36 8879 Provide Wave Names skip column skip column vf Double precision Overwrite existing waves Make table Skip this block 5 Wave wavenarme Column Number 2 Column Format Number Skip Column d Help Quit Figure 21 Image of the Loading General Text window 55 2 Four gamma ray peaks the 1779 5107 5618 and 6129 keV lines are fit using Hamara s Fit Gauss with Tail Igor routine to determine the centroid channel for each energy peak e Under the Gamma menu select Fit Gauss With Tail Utilities D Update Calc Params Calibrate Spectrum Manual Calibrator Auto Calibrator Spectrum Info Spectra gt counts hour Sandbox Display POI Table Load POI Table Save POI Table Loa
172. troscopic survey A feature based taxonomy Icarus 158 146 177 10 DeMeo F E Binxel R P Slivan S M and Bus S J 2009 An extension of the Bus asteroid taxonomy in the near infrared Icarus 202 160 180 11 Jones T D Lebofsky L A Lewis J S and Marley M S 1990 The composition and origin of the C P and D asteroids Water 1s a tracer of thermal evolution in the outer belt Icarus 88 172 192 12 Hiroi T Zolensky M E Pieters C M and Lipshutz M E 1996 Thermal metamorphism of the C G B and F asteroids seen from the 0 7 micron 3 micron and 100 UV absorption strengths in comparison with carbonaceous chondrites Meteoritics and Planetary Science 31 321 327 13 Rivkin A S Davies J K Johnson J R Ellison S L Trilling D E Brown R H and Lebofsky L A 2003 Hydrogen concentrations on C class asteroids derived from remote sensing Meteoritics and Planetary Science 38 1383 1398 14 Campins H et al 2010 Nature 464 1320 1321 15 Rivkin A S and Emery J P 2010 Nature 464 1322 1323 16 Schorghofer N 2008 Ap J 682 697 705 17 Prialnik D and Rosenberg E D 2009 Mon Not R Astron Soc 399 L 79 L 83 18 Gaffey M J Cloutis E A Kelley M S and Reed K L 2002 Mineralogy of asteroids Asteroids IIT 183 204 19 McCoy T J et al 2001 The composition of 433 Eros
173. uisition by the PING instrument set 51 up on the basalt monument Since the neutron inelastic scattering gamma ray production rate is proportional to the fast neutron flux we assume that a stable gamma ray count rate can be obtained from the time the pulse start signal 1s given to the PNG 10n source t 0 us We can examine the time dependence of the fast neutron induced gamma ray flux from the time of the pulse start signal to the end of the PNG pulse t 0 to 100 usec to look for anomalies In this example we generated gamma ray energy spectra for each of ten time Slices time slice width 10 us of the gamma ray data during the PNG pulse and determined the 6129 keV net gamma ray peak count rate and its associated uncertainty for each time slice Table 3 lists the time range for each time slice the 6129 keV peak count rates and the uncertainty in the count rates for each of the ten time slices Note that the count rates in the first and second time slices are inconsistent with the count rates in the 8 other time slices and that the count rate for these later 8 time slices 1s constant as expected The low 6129 keV gamma ray count rate during the first time slice t 0 10 us indicates that the PNG has not begun producing fast neutrons yet since there 1s a delay between the time that the PNG 1s sent the burst on command signal and the time when fast neutrons are actually being generated by the PNG The higher 6129 keV gamma ra
174. unplugged Figure 15 Lynx DSA Images of a the front and b the back showing connection ports for HPGe of the acquisition system The MultiScan software was written 1n Java since we needed to make the code cross platform and easy to understand so that others can make changes to the code when 37 necessary When starting a new data acquisition or scan the user can specify which of the multiple Lynx DSAs to perform the scan the acquisition mode PHA or TLIST the file format to save the data Canberra CNF file ASCII text file or both how many consecutive scans to perform and the duration of each scan in either live time or true time Settings can be modified quickly and easily within the software The data are both written to a file and presented in a large display window with multiple data visualization features The program also provides basic data analysis tools for both PHA and TLIST scans and off line TLIST data post processing time slicing tools as well as a diagnostic feature for monitoring the operating parameters within the Lynx DSA 65 Details of the experiment operations manuals can be found in Appendix III 38 CHAPTER III DATA ANALYSIS AND MCNPX CALCULATIONS Experimental Data Analysis The following sections Experimental Data Analysis through Identifying and Removing Sources of Systematic Error Using TLIST data are all from the peer reviewed publication in J Bodnarik et al 2013 Time Resolved Neutron
175. y count rate in the second time slice t 10 20 us is also inconsistent with the average value for the other slices and may be due to a systematic error induced by the gamma ray detector electronics In both cases we can choose to exclude these data points from further analysis since they are not representative of the constant inelastic gamma ray flux during the PNG pulse The number of neutrons produced between bursts is negligible 52 The PNG is designed to have a well defined repeatable neutron burst shape with a sharp 14 1 MeV neutron cutoff between bursts that enables optimum timing of the inelastic and capture measurements and a capture measurement uncontaminated by inelastic gamma rays 67 68 To be sure we would investigate the origin of the systematic errors that prompt us to remove the data from the main analysis Without this event by event time and energy data however these points would have been unexamined and included in the data skewing the results Excluding the data from the first 20 us will increase the statistical error on the mean value of the 6129 keV gamma ray production rate but will result in more accurate data that we can use to infer the bulk elemental composition of planetary material This is clearly seen by comparing the 6129 keV weighted mean count rate and uncertainty for time slices 3 through 10 t 20 100 us which is 42 1 cts us 1 10 cts ms versus the 6129 keV weighted mean count rate and uncertainty
176. y Composition by In situ and Remote Gamma Ray Spectrometry in Remote Geochemical Analysis Elemental and Mineralogical Composition ed C Pieters and P Englert Cambridge University Press pp 395 411 49 Evans L G Reedy R C and Trombka J 1 1993 Introduction to Planetary Remote Sensing in Remote Geochemical Analysis Elemental and Mineralogical Composition ed C Pieters and P Englert Cambridge University Press pp 167 198 50 Feldman W C et al 2000 Chemical Information Content of Lunar Thermal and Epithermal Neutrons J Geophys Res 105 E8 20347 20363 51 Grau J A Schweitzer J S and Hertzog R C 1990 Statistical Uncertainties of Elemental Concentrations Extracted from Neutron Induced Gamma Ray Measurements JEEE Trans Nucl Sci 37 2175 52 Evans et al 2006 J Geophys Res 111 No E3 53 Evans et al 2001 Meteoritics and Planetary Science 36 1639 1660 54 Prettyman et al 2006 J Geophys Res 111 E12007 55 D B Pelowitz et al 2005 MNCPX User s Manual Version 2 5 0 LANL Los Alamos LA UR 05 0369 56 Boynton W V et al 2004 Space Sci Rev 110 37 57 Knoll G F 1989 Radiation Detection and Measurement John Wiley and Sons New York Chapter 14 103 58 Schweitzer J S 1993 Subsurface Nuclear Measurements for Geochemical Analysis 1993 Chap 23 in Remote Geochemical Analysis Elemental and Mineralogic
177. y that is 0 087 17 35 Even with the large uncertainty associated with the MCNPX ratio the two ratios differ approximately by a factor of 2 The Al Si experimental ratio as compared to the MCNPX ratio is 1 184 1 27 and 0 134 5 43 and they differ approximately by a factor of 8 8 The Fe S1 experimental and MCNPX 88 ratios and uncertainties are 1 455 0 86 and 0 019 19 27 even with the large uncertainty on the MCNPX ratio both ratios differ approximately by a factor of 76 6 The C Si experimental and MCNPX ratios and uncertainties are 1 349 1 27 and 2 208 1 55 and they differ approximately by a factor of 0 6 The O Si experimental and MCNPX ratios and uncertainties are 0 457 1 35 and 0 675 1 95 and differ approximately by a factor of 0 7 Table 15 Gamma ray Element Si experimental and MCNPX ratios for the asteroid simulant Na Si 0 176 5 87 0 087 17 35 Nasi 0176 587 0087 1735 In general all of MCNPX ratios are less than their corresponding experimental ratios with the exception of the C S1 and the O Si ratios that are larger than its corresponding experimental ratios and are in fairly good agreement The Al Si experimental ratio as compared to the MCNPX ratio differs by an approximate average factor of 8 8 and this difference could be due to the lack of Al in the model as mentioned in the discussion about Table 13 The Na Si ratios differ by a factor of 2 The lower value of the MCNPX Na Si ratio c
178. yed activity peaks are present at all times if these counts were not subtracted from the peak measured during the high energy neutron pulse the derived elemental concentration would be much too high This effect can be seen in the data in Table 3 If we did no time gating and assumed that the 1779 peak was only due to silicon we would have 90480 0 48 counts and for oxygen at 6129 keV we would have 19920 1 1 counts The Si O ratio would then be about 4 5 Even rudimentary time gating changes the results to 31730 1 and 10900 1 67 counts respectively by selecting only the counts in the inelastic window The ratio of the 1779 to the 6129 is now 3 rather than 4 5 much closer to the ratio expected from the elemental abundances If we further correct the counts in the inelastic window by the contribution from the delayed activity the areas become 26273 1 2 and 10045 1 8 counts for the 1779 and 6129 keV peaks respectively and the ratio of S1 to O is now further reduced to about 2 5 This improved accuracy is obtained with only minor deterioration 49 in the percent error that is purely the precision of the measurement Note The actual S1 O ratio 1s approximately 0 5 however the energies of the lines used to determine the 1 and O content are of sufficiently different energies that the detector efficiency differs by a factor of four thus increasing the measured value from 0 5 to gt 2 The use of optimized time wi
179. ype C Ivuna like carbonaceous chondrite meteorite Mighei like carbonaceous chondrite meteorite Canberra file format Carbonaceous asteroid spectral type C a k a C complex Dynamic Albedo of Neutrons experiment on MSL Deuterium Deuterium Digital Signal Analyzer Deuterium Tritium Full Width at Half Maximum Full Width at Tenth Maximum Goddards Geophysical and Astronomical Observatory Galactic Cosmic Ray Gamma Ray Spectroscopy Goddard Space Flight Center High Density PolyEthylene High Purity Germanium detector Lunar Reconnaissance Orbiter Mercury Surface Space Environment GEochemistry and Ranging Monte Carlo N Particle computer code Monte Carlo N Particle eXtended computer code Message Passing Interface Mars Science Laboratory National Aeronautics and Space Administration NASA Center for Climate Simulation Near Earth Asteroid Rendezvous a k a NEAR Shoemaker NASA Near Earth Asteroid Rendezvous Shoemaker mission Near Infrared light Neutron Spectroscopy Pulse Height Analysis Probing n situ with Neutrons and Gamma rays Pulsed Neutron Generator Princeton Technology Center a difference in energies of parent and daughter nuclides Time stamped LIST mode Ultraviolet light Visible light Visual Editor interactive graphical user interface tool for MCNPX X Ray Spectroscopy X1V CHAPTER I INTRODUCTION Asteroids are remnants from the formation of the Solar System about 4 6 billion years ago and thus contain

Using in situ neutron and gamma-ray spectroscopy to

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