GammaVision How to Guide Make Gamma Ray
Contents
1. Note In the next section you will manually build an efficiency library and calibrate your system for efficiency Calibration Wizard vs energy In Steps 1 21 and 1 22 you will insert the Fig 21 peaks that you wish to include For this procedure be sure to insert the peaks beginning with the lowest up to the highest energy th Library ORTEC 11 30 17 4M Thu 12 26 00 1 21 Begin selecting the nuclides for the efficiency calibration beginning with the lowest energy peak in your nuclide list In this example Am 241 is the lowest energy nuclide in the 2 L Marinelli standard source Move to the Am 241 peak RSRREE by using the Peak selection tool on the right hand sidebar of the MCA window Fig 23 Check the energy of each peak by clicking Delete Erity Peak Info as in Step 1 8 or by viewing the Recal save status line at the bottom of the MCA window Fig 23 Efficiency T able 2 59695 O02 B 5946 002 at 661 6600 kel Enter Calc r 000E 003 7000E 003 29r r1E 002 2 977r2E 002 3 9547E 002 3 9547E 002 2 HO4B6E 002 1173 24 1 6793E 002 1 6761E 002 0 07 1332 50 T 5503E 002 1 5512E 002 0 06 1836 01 1 3129E 002 __ 1 3128E 002 _ 0 014 Delete Entry Recall Save Polynomial od 1 22 Follow the following procedure for Below onoma lil each peak selected Choose Enter from the Fig 24B i ie Calibr window Fig 24A an entry will2. Cancel Settings 3 4 Upon completion of the count choose Analyze Entire Spectrum in Memory Fig 47 The Sample Definition File stored all analysis option parameters that were created in Step 2 A report will be generated on the Spectrum on Disk screen this action will invoke the Notepad Display analysis Results software to create the report that was setup in Step 2 13 Fig 39 Peak Search ROI Report Entire spectrum in memory Fig 46B Interactive m viewed atea Fig 47 3 5 The report contains all relevant data and information about the calibration collection date and time spectral analysis program and a summary of the activities of the nuclides in the PondB library that was created in Step 2 Fig 48A Sample description B 9 meters Pond B Sept 2008 Sampling Spectrum Filename D GammaVision Workshop fon s Machine Sept2666Samp ling PondB9m Ant Acquisition information Start time Live time Real time Dead time Detector ID H8 Dec 2Z088 08 37 14 86498 B 11 1 Fig 48A Calibration PG AGE Filename 1835 2 L Marinelli GEH 100 FondE9m nd Energy Calibration Created ero offset Gain Quadratic 87 Dec 2668 16 58 34 0 059 kell 0 217 kel fchannel 23S5E 68 kel channel 2 Efficiency Calibration Created Type Uncertainty Coefficients 16 Dec 2068 10 29 37 Polynomial 1 863 0 728344 3 254841 H 848199
3. ENG anmmavision Workshop Gamma Browse Browse OF Cancel Help Fig 36 Analysis Options Fy x Sample System Decay Report Analysis Corrections Isotopes Laboratory name FerkinE Imer ORTEC Operator name ORTEC User MOA Type PEAK SEARCH SENSITIVITY Traditional ORTEC Library Least Most OI ma a 5 Unita Bg Multiplier i o0000 i pEi Divisor i o0000 Activity Bg SIZE i Ko Match width 0 5000 PHM kev Fraction Limit 0 0000 Percent File for Suspected Nucldes E UeerSuspect Lib Browse Cancel Help Fig 37 Sample System Decay Reporf Analysis Corrections Isotopes Decay Correction Date BA r00 Time 2 00 00 AM M dyu h mm ss tt I During Acquisition Sample Collection I Collection Sample Start Date Ea Time 8 3714 AM Sample End Date 12 5 00 Time 8 3714 4M Midu h mm 2 tt Cancel Help Fig 38 Note GammavVision has the ability to create numerous Analysis Options zia custom reports The settings chosen here will generate a Sample System Decay FeportfhAnalsis Conections Isotopes simple report for illustration For more detailed reports please consult the GammavVision 32 V5 2 manual Uncertainty Reporting ie Percent Counting Activity i Total Reporting Options 2 14 Click the Analysis tab to choose an Analysis Method Library
4. appear in the Efficiency Table Select the Fig 24A entry in the table then click Calc Calibr Eq Fa Efficiency Efficiency Calculation Worksheet EAE from the Calibr ox BEENA window Fig 24B J 7 7o01e 003 Cancel at 18366177 kev Calc Assay from Certificate Peak Measured from Spectrum the Efficiency Calculation Date 4 1 98 12 00 00 Pla Date 12 6 00 5 31 42 PM Teale hl Ady h mm ss t CPS 12 95 allie Worksheet window Delete Entry Muclide Recall Save will appear Fig Activi 16220 GPS F Half Life 157788 00 Days 24C Complete Uncertainty 5 0000 Gammas 100d 3 6300E 0 Mode i Above the form using the From Library D Am 241 Pobnomil ial information from Linear z Fig 24C your Standard Polunomial Certificate and click Calculate Efficiency When you have completed the form and the efficiency has been Fig 25A calculated click OK to return to the MCA window mem 0 Energy key 3559 Fig 25B 1 23 Repeat this procedure for each nuclide in your standard source that you wish to include in the efficiency calibration Be sure to insert the peaks in ascending order by energy 1 24 Once you have selected the peaks for your efficiency calibration choose Polynomial from the Mode list in the Calibr window Fig 25A The resulting fit should look similar to the one obtained in this example Fig 25B 1
5. Fig 48C EEHEHE sUHHARYFY F HUCLIODES I H Time of Count Time Corrected Uncertainty Activity Activity Counting Bg L Bq L gt AHPLE 2 Sigma NHuclide Total C3 137 RA 226 8856E 61 3 60491E 08 TH 234 f r99 0E 00 AH 241 lt x 1 09 08E H1 MDA value printed Activity printed but activity lt MDA 1265E 681 d 6495E6E 68 f 3567E 681 1 89 77E 61 5 6915E 08 3 2259E 681 2 43376E 01 6 6178E 008 3 25556E 01 2 46977E 01 Activity lt MDA and failed test Area lt Critical level Failed fraction or key line test Halflife limit exceeded Figure 48 Excerpts of information included in the report that was created in Step 2 The report contains Sample Identification information Fig 48A calibration data Fig 48B and a summary of the activity concentration of the nuclides of interest Fig 48C Congratulations By following this How To Guide you have completed a number of the steps needed to make gamma ray measurements using GammaVision 32 V5 2 You have also familiarized yourself with a number of the important features and tools that will make implementing GammavVision for your application simpler and faster Reference 1 Gilmore G amp Hemingway J D 1995 Practical Gamma Ray Spectrometry John Wiley and Sons NY NY 2 Knoll G F 1989 Radiation Detection and Measurement Second Edition John Wiley and Sons NY NY 0901 ORTEC HOTLINE 800 251 9750 wiww ortec o
6. counting GammaVision also allows the user to decay correct during sampling the Collection check box under Sample Collection Since our analyte is Cs 137 t1 2 30 2 years the corrections for our example are negligible the sample was collected over a 30 minute time period and count time is about one day much less than the 30 year half life 2 13 Click the Report tab Fig 39 e Uncheck the four Reporting Options checkboxes e Choose Percent and Total under Uncertainty Reporting and 2 Sigma under Confidence level to report a 2 sigma confidence level uncertainty as a percent of the activity concentration you may also choose to report uncertainties in activity units e Under Output check Display Analysis Results and choose Program You must choose a text editor to display the results In this example we have chosen NOTEPAD EXE Choosing these options invokes the NOTEPAD text editor and displays the report when an analysis is performed Analysis Options EE Analysis Options EAE sample System Decay Report Analysis Corrections Isotopes File JEG ammavision Workshop GammaV i fe Creation 12 29 00 11 30 44 4M Edition 12 25 00 17 55 52 Description One Day Count for Pond B Samples Presets Analysis Range Random Summing From 200 To eoon jo Background Type f Auto Point 3Point 5 Point Nuclide Library Save As Calibration Internal I Internal 7 JESU zer PondB Lib
7. library to the list of Edit File Fig 14A nuclides contained in the Fiecall Save Standard Certificate for your Fi O C standard source You ma brew 3 y C FWHM Files of type Giammavision Libary I delete nuclides from the list I No FWHM Cal Fig 14B by highlighting the nuclide and selecting Cut Fig 16 Auto Calibrate Fig 13 Editing Calib Lib Creation 4 73 7868 10 56 04 AM Edition 475795 8 19 53 AM Select Peak Ce137 Sr 113 Select File 58 Edit ny Hg 203 e m 241 Rank Energy Percent List end a9 03 3 6100E 000 2 22 16 8 6000F 001 24 94 1 7O00E 001 Fig 15 Inzert Cut Edit Cut Insert Copy ee Insert Paste Fig 16 Cd 109 Cadmium Half Life 436 Days Uncertainty 5 4000 Calibr RA EG Energy Peak 6136 05 E 1332 4017 ke Table 6 Energies Delete Energy Recall Save Fit Energy C FWHM M No FWHM Cal Auto Calibrate Cancel 1 16 To add a nuclide to the list click Insert Input the Nuclide Name Half Life and Uncertainty information from the standard certificate and click OK Fig 17 The check boxes in this window are designed to flag nuclides of your choice for reporting purposes We ll skip this for now 1 17 Choose Auto Calibrate in the Calibr window to calibrate energy and FWHM Fig 18A The energy calibration table and a graphical
8. representation of the fit will appear The energy vs channel fit should appear linear Fig 18B If not return to step 1 14 and carefully compare the list of nuclides in the library to the list of nuclides on your standard certificate the energies must match Another way to check the energy calibration is to inspect the Delta values in the Energy Table Fig 18C These values are a measure of how well the calibration fits the actual data points For a well shielded system the Delta values for a good energy calibration should be small typically less than 1 1 18 Inspect the FWHM calibration by selecting FWHM in the Calibr window The table and aoe graph will immediately E 88 0341 keV display Fig 19 The E trend for the FWHM is 11 Energies increasing with energy Delete Energ although non linear Recall Save 1 19 Save the energy trew calibration by choosing So i F No PWwHM Cal weve a mg Calibr E window Browse to the Auto Calibrate directory where you Fig 18A Fig 18B would like to store the Channel Insert Library Nuclide EES Huclide Hame Hate o EE Uncertainty ooo Nuclide Flags Thermal Neutron Activation T T Fast Neutron Activation F T Fission Product I T Naturally Occurring Isotope H T Photon Reaction F Charged Particle Reaction C T No MDA Calculation iM D Activity Mot in Total 59 47 405 67 oo U2
9. will appear Energy Energy Table and Calibr Fig 12B These windows may be selected and moved by left clicking and dragging the upper colored part of each window ra w Efficiency Description Recall Calibration Save Calibration 1 12 From the Calibr window choose the E FARIGI Windows icon in the upper left hand corner and scroll to Destroy Fig 13 This will eliminate any existing calibration information Calibration Wizard Channel Energy Table X Fig 12A Note GammaVision manages analysis information in the form of T O e7 C T N E T libraries There are a number of libraries that are included with o leo ee tane 661 62 3047 76 661 67 0 01 Gamma Vision For calibrations the Calib library contains a list of common nuclides included in full soectrum calibration sources 1 13 Choose Library Select File Fig 14A The Calib library Fig 12B resides in the User directory by default If you have moved the Calib library browse to the correct directory Select the Calib library and click Open to load this library Fig 14B 1 14 Choose Library Edit GammaVision Editor Fig 15 A window appears containing _ Library Load Library File the nuclides included in this BEZAIA xa library and the peak Close Alt F4 eee sits a ee Lib estore Ee i Lib4 information for each peak i pa iea n Pe Inui 1 15 Compare the list in the eee T r en Calib
10. 25 To save the efficiency calibration click Save inthe Calibr enprese HE window browse to the working directory name the file and click swei GiGanmaViionHowto Gl ed E a Save Fig 26 1 26 Once the efficiency table file has been saved exit the calibration by clicking the X in the upper right hand corner of the Calibr window 1 27 Next save the complete calibration as a clb file that can be recalled at any time for analyzing samples of this geometry Filename 1835 2L Marineli Et and matrix 2 L water samples in the Model 138 Marinelli beaker Save as type En Fies Cancel geometry see Step 1 1 1 28 Choose Calibrate Save Calibration Fig 27A Browse to the working directory name the file a representative name is recommended and click Save Fig 27B A dialog box will appear to allow you to input a detailed description of the calibration Fig 27C Input the description and click OK Fig 26 Calibrate Save Calibration File EES Calibration Description Energy Save in E Gamma Vision HowTo Gl e k oF cil 1835 2 L Marinelli GEM 100 w Efficiency Cancel Description Fig 27C Recall Calibration Save Calibration Print Calibration Calibration Wizard Filename 1835 2 L Marinelli Cal Fig 27A Save az type Cb Files Cancel Fig 27B 2 0 Sample Type Setup Libraries and Analysis Options Note GammaVision is designed with the flexibili
11. J Gamma Vision HowTo Calibration Internal Iw ne Browse Intermal Iw ee Browse File name 2 Marinelli Water Sampled L seve Save az type Sdf Files ms Cancel Fig 35 2 10 Complete the Sample tab by performing the following Fig 36 can be used as a guide e Click Presets and place the cursor in the Live Time input box and type the number of seconds for your count for this example input 86 400 seconds a one day count Click OK and type in a description for your ample counts e Type in an Analysis Range From 200 To 16 000 and set Random Summing to 0 e Select the Auto Background Type e Click Browse to select the Nuclide Library that you created in Steps 2 1 to 2 7 e Click Browse to select the Calibration that you saved in Step 1 28 e Uncheck the Internal check boxes for Nuclide Library and Calibration 2 11 Click the System tab and perform the following Fig 37 can be used as a guide e Fill in the Laboratory and Operator name fields e Choose the Traditional ORTEC MDA Type e Set Peak Search Sensitivity to 3 e Complete the rest of the form as shown in Figure 37 2 12 Click the Decay tab and complete the form as follows Fig 38 can be used as a guide e Check the Decay Correction Collection checkbox this decay corrects to the sampling date e Fill in a Date and Time Note The During Acquisition checkbox decay corrects the sample for decay during
12. O02 nb 46 122 07 0 00 628 96 136 51 0 064 F642 165 86 0 023 391 67 energy calibration name the file a representative name is recommended and click Save Fig 20 Click the X in the upper right hand corner of the Calibr window to exit the efficiency calibration workspace The working energy calibration is now the file that you just saved this includes FWHM and energy vs channel number FYfHH Table Calibr AES Save Energy T able File EE Energy 59 1 01 0 98 3 49 Peak 3275 68 Savein E Gamma Vision HowTo A al ele 49 AEEA 58 03 1 03 1 01 1 972 MDEE 122 07 1 06 1 04 213 Enter 136 43 1 02 1 05 3 6422 Table 11 Energies Delete Energy Recall Save Filename 1835 2 L Marinelli Energy Cal FWHM K I No FWHM Cal Save as Ippe lentFies sts lt s sY Cancel Enerngy ke Auto Calibrate Fig 19 Fig 20 Pulse Ht Analysis Start 1 20 To begin the Efficiency Calibration choose Calibrate 3 Calibr a ES Calibrate Efficiency Fig 21 Next click the Windows Energy mae ieee icon in the upper left hand corner of the Calibr window t eel fe Reet and select Destroy Fig 22 This will eliminate any Description Table oe existing efficiency calibration information the energy Recall Calibration Restore and peak width calibration will remain intact save Calibration Print Calibration
13. ORTEC GammaVision 32 Version 5 2 How To Guide Make Gamma Ray Measurements Today Gamma Vision 32 V5 2 is an integrated gamma spectroscopy data acquisition and spectral analysis software program that operates with the ease of the Windows based operating system environment By reading in this How To guide you will learn the basics of GammavVision and begin making simple gamma ray measurements You will need a Standard Source and the certificate information for the calibration exercises carried out in the example System used for this How To Guide GammavVision is a dynamic software package that is capable of recognizing a number of hardware configurations The software is designed not only to determine the hardware that is connected but also to enable only those features of GammavVision that are supported by the hardware that you have connected GammaVision 32 V5 2 can support any mixture of the following types of units with proper hardware configuration and installation 916A 917 918A 919 920 921 926 92X NOMAD Plus NOMAD MicroNOMAD OCTETE PC TRUMP TRUMP PCI MicroACE DART DSPEC DSPEC Plus 92X l1 MatchMaker M CA and other modules The DSPEC Plus Digital Spectrometer was chosen for this How To Guide due to the increasing popularity of this state of the art product Components used for creating this How To Guide Item ORTEC Model No Description Function GammaVision 32 V5 2 A66 B32 Gamma spectrosco
14. Once you have determined the needed count time Copy to Buffer for your calibration you will need to preset a value for Zone the count time Choose Acquire MCB Properties cee Preset Limits Click in the Live Time input box and type MakRGl a the desired Live Time in seconds for your calibration Clear ROI j Feak Info Fig 11 Input FE Fig 10 1 10 Choose Acquire Start and allow the system to nu accumulate counts for the preset live time When the eaves acquisition is complete choose File Save and save the Fig 9 file to an appropriate working directory Presets Ei Ea Note There are three steps to conclude the calibration process Standard Presets MDA Preset Energy Calibration Peak Shape Calibration FWHM and Uncertainty Efficiency Calibration Each step involves selection of peaks in the T spectrum input of known peak information and archiving of the e6400 00 Live Time spectra and peak information You will calibrate the energy first oe Start Chan 7190 0 peak shape is also accomplished with this step Next save the mA width 657 energy calibration ent file to the working directory then calibrate for efficiency and save the efficiency calibration eft file Finally you will save the spectrum as a clb file that contains all the calibration information needed to analyze your samples Suggest Region Cancel Fig 11 1 11 Choose Calibrate Energy Fig 12A Three new windows
15. Ra 226 in the PondB Editor Window Fig 33 Repeat this MM NucideFlags exercise for Th 234 Close the Suspect list by clicking the X in the upper right hand corner of the window Close the PondB end library in the same way You will be prompted that the library has been changed and asked to save the changes answer yes to these questions and you will return to the MCA window Note You have now completed the steps necessary to calibrate your system for three basic parameters e Energy vs Channel Number met ff q Edt o Peak Shape FWHM Insert kopy Paste Hg 20 onset Dey e Efficiency vs Energy Nucide Cu H20 Now to create a template that can be applied to many samples Fig 30 We will apply the template to the analysis all samples in this group Editing PondB_Lib Ei ES Load Master Library File Move Am 241 Armeni iuni ai a User Close Alt F4 Half Life 432 v s Uncertainty 5 0000 T i how Mache WAT 2 Show Master Librar Nuclide Flags Hew Edit Am 241 Restore Peaks Sort Leed Ube Sicha AA kais 59 54 3 6300E 001 File name Suspect Files of type Gammavision Library Cancel Fig 32 Suspect Lib Editing PondB_Lib Ei leet Eopy Faste H 203 nst Pase J134 Le l A Creation 413788 1058 04 4M Am 24 Americium J 135 Hf 181 Edition 14729700 10 35 21 AM Half Life 432 Yrs Nuclide Sle Were f A
16. cription of the file Ri cle formats included in GammaVision Fig 41 Fig 42 software 3 0 Sample Analysis and Reporting Acquiring File Settings EE Saving and a Simple Report General Export Impor ree Note When GammavVision performs an analysis a number of reports are generated some user driven some automatic The default settings for archiving these reports is located from the main MCA window under File Settings choose Directories to inspect the defaults Fig 43 To modify these settings choose Modify from the Directories tab and browse to the directory of your choice DAU serhCeth20 Spectra DL ser ROI Files DL ser Libraries DL ser Job Files D User Reports DL ser T able Files D User Sample Types DL ser Calibrations DL ser For our example we chose to display the reports but not to mora archive the reports Step 2 13 we could have easily chosen to create a report display it for review and archive the report in a user defined directory in Step 2 13 Fig 43 3 1 Fit your sample on the detector in the same manner as the standard source used for calibration In this example we are analyzing six water samples for Cs 137 The sample analysis and reporting characteristics that are common to all of the samples are included in the Sample Definition File sdf created in Step 2 The Live Time Preset was set in Step 1 9 Acquire MCB Properties Next we will set up an automated dialo
17. e we analyze 2 L ground water samples in a Marinelli beaker geometry The sample was collected from a seasonally anoxic lake in the Southeastern United States Our analyte of interest is Cs 137 with a primary gamma ray full energy peak of 661 7 keV To make these gamma ray measurements you will need to accomplish the following tasks e Calibrate the detector energy efficiency and peak shape e Count your sample e Analyze the spectrum e Create a report To best use this How To Guide it is recommended for the first time user in particular that the steps be followed in order from start to finish 1 0 Calibration Some things you should know You need to calibrate your system for three basic parameters e Energy vs Channel Number e Efficiency e Full Width at Half Maximum peak shape Energy vs Channel Number When a gamma ray photon is absorbed by a germanium detector a small signal often termed a pulse is produced The signal is amplified and filtered in such a way as to reduce noise and produce a clean signal The magnitude of the net signal is proportional to the energy of the photon i e photons with greater energies produce larger pulses A device called an Analog To Digital Converter ADC is used to convert each pulse into a channel number larger pulses will be converted into a higher channel Each pulse is registered as a count in a unique channel by the Multichannel Analyzer MCA The result is a histogram of pulse
18. e the embedded features of GammaVision to determine the number of net counts in a Region of Interest ROI Place the cursor to the left of the peak of interest Left click and drag the cursor across the energy peak a box will appear as you drag the cursor Fig 8A Once the box encompasses the entire width of the peak stop and unclick The box will remain in the window Next right click within the box and select Mark cae ROI Fig 8B The result is a highlighted ROI Fig 8C To view the Mak ROI attributes of the peak right click within the region and select Peak Info Fig 9 An information box will appear that contains relevant information ee about the selected region Fig 10 In this example we find that the number of net counts the area of the peak above the background for Fig 8B the 1173 keV Co 60 peak is 3 302 351 counts well in excess of the needed counts for good peak statistics lt 0 1 in this case for an energy calibration Repeat this exercise for other peaks of interest for your standard source Scale the count time for your calibration to ensure good statistics for all the certified nuclides in your Clear Copy to Buffer Zoom In Fig 8C MCB Properties Peak 5402 98 1173 33 key FWHM 2 05 PA 5 M 3 28 Library Co 60 Cobalt at 1173 24 2257 55 Bq Gross Area 3656497 Met Area 3302351 3511 Gross Net Count Rate 42 32 7 38 22 cps Start standard source i 1 9
19. ee ae Cs 137 Uncertainty 5 0000 e135 Audg6 9 P o Acie Faga Fig 31 xe 138 Au 198 end Cs 134 Ho 203 Cs 136 TI 208 1 Cs q137 Pb 210 2 8 Choose Analyze Settings Sample Type ee Fig 34A to open the Analysis Options dialog ecm Hoe Rank Energy Percent Ba 139 Bi 212 1 59 54 3 6300E 001 window Fig 34B 02 139 Bi214 Ce l41 Ra z24 2 9 Select the Sample tab We are creating a 113 Cela EE 7 amp template to use for many samples we will eae save this template as an sdf file that can be Eu152 Eu 1 54 applied to all our analyses Click Save As e132 Eu155 Gd 153 T w _ edt fc from the Sample tab browse to the working ee inset R22 Paste Ha 209 Insert Paste directory name the file and click Save Fig mea 35 Fig 33 Analyze Analysis Options X sample 5 stem Deca Re ott Anal sis Corrections lsoto es SS ee y J p M p Peak Search eee E ROI Report TERUR oe ile ooo Bro a E Enti n Geometry Correction Creation Edition Entire spectrum in memory Spectrum on Disk Peak Background Correction Description E Priesai Display analysis Results Average Energy Analysis Range Random Summing From f 0 To eoon jo Background Type f Auto C 1Point 3Pont 5 Point Nuclde Library lodine Equivalence DAC MPC Interactive in viewed area Fig 34A Select Defaults File Save ir
20. erence section of this How To Guide Amplifier Amplifier ADC Baseline Restore Auto Freamplifier Type Fiesistor Feedback E Ama Clih siae 10 Se Cailean Secu 12 OF 00 2L Aerts 1825 Amwey mmr li 1 epi Ele Ae iu Tikes Detector Chrl lt Fri gt Detector Buffer F4 or Alt 6 Keypad Keypad t Logarithmic Automatic Baseline Zoom h keppadi Keypad Keypad 5 Ak F7 Zoom In oom Out Center Eull View Preferences Fig 5 Presets Fig 7 Thumbnail MDA Preset Optimize Input Polarity J Start Auto Stop Abo HIHI I Stabilizer High Voltage 1 7 The first step in the energy calibration is to collect a spectrum using a standard source consisting of nuclides with known energies The length of the count will be dependant on the count rate in the peak energy regions of your standard calibration source and the counting statistics that you would like to achieve A good rule of thumb for the number of counts in the full energy peak region for calibration is 100 000 0 3 counting statistics GammavVision allows you to preset a limit for the count time real time or live time peak centroid counts or Region Of Interest ROI integrated counts 1 8 To determine the needed count time choose Acquire Start Count for several minutes then choose Acquire Stop Here you will us
21. g that will guide the user through input of the parameters that are unique to the a ee individual samples in this group These Start Save Eleport Acquisition Settings Acquisition Settings EES Stark S aveAeport T Clear at Start Save File 2 P Auto lncrement File Prefix Cancel Eagt SI lee characteristics include ee n Eo Copy to Buffer Alt 5 4sk an Start Options e th le aa Sample Description A r l Sample Type sion Workshop Gamma vision HowTo Browse i Sample Size Acquisition Presets ew Stored Spectr 3 2 To setup the user dialog for input of Field iloa Operation F Sample Description these unique sample parameters choose gaase pom kag Acquisition Settings Fig 44 If the Ga F Collection Date 01 Dec00 Time 1200 00PM Sample Definition File created in Step 2 is Fig 44 I Sample Stat Date sims PSS not selected in the input box browse to the SampleEndDate Tm file location and choose open Place a checkmark in the iit wba boxes for Sample Description and Sample Size and click Fig 45 OK Fig 45 Sample Description 3 3 Select Acquire Start Dialog boxes will appear which require user input for sample information prior to the start of feces eens the acquisition Fig 46A B Input the information for each E dialog box and click OK The information is now stored with i the spectrum for analysis Once the input parameters are complete the count will begin B LI ha o kg
22. ision Editor Fig 28B Fig 28C Editing Calib Lib HES Move Cd 109 Cadrniurn 2 4 Since we are interested in Cs 137 and a few other Close Alt F4 Half Life 436Days naturally occurring radionuclides we may delete several of the Show master Library ee e isotopes used for calibration Save this library with a new name New edt C4108 that represents the type analysis it will be used for Click the fae Peaks Windows icon in the upper left hand corner of the editor and Pere Peak Flags G choose Save Library As Fig 29 Save the library with a Save Library As 2 16 8 6000F 001 24 94 1 7000E 001 representative name in this example we call the library PondB 2 5 To delete isotopes from the library highlight the isotope in the list with a single click and choose Cut Fig 30 Delete all of the isotopes in the library list except Cs 137 and Am 241 Cut Edit Cut Insert Eopy Paste nete Dre 2 6 To add nuclides to the library list click the Windows icon in the upper left hand corner of the editor and select Show Master Library Fig 31 Choose the Suspect library list from the User Fig 29 directory and click Open Fig 32 Editing PondB Lib Fy E 2 7 We will add Ra 226 and Th 234 to the library Highlight Ra Creation 4 13 88 10 58 04 AM Am 241 Americiur i i i ition Ha Half Life E 226 from the Suspect list with a single click Next click Insert _ aes Sa
23. k width with increasing energy is necessary for measurement of peak area and for peak fitting By convention peak width is measured by Full Width at Half Maximum GammavVision allows the user to calibrate peak width using the same spectrum as energy and efficiency In this example the auto calibration feature is used for peak width calibration Calibration Getting it Done 1 1 Fit the calibration source on the detector endcap and close the shield In this example a 2 L Marinelli beaker standard source was used The standard matrix is an epoxy with a density of 1 0 gecm the density of water The water samples to be analyzed must use this same 2 L Marinelli beaker geometry and be the same density 1 2 From the Windows desktop click Start Programs GammaVision 32 GammaVision Fig 1 This will invoke the GammavVision software Your view z will be of the Multichannel Analyzer MCA emulator window The MCA emulator H7 window is the main interface for working with GammavVision There are nine menus to choose from e File j Acquire Acquisition Settings e Calibrate EE e a e Calculate Ae e Analyze Cayto Bufer AK5 e Library gA e Services aires o ROI ZDT Display Select F3 Display MCB Properties 1 3 Choose Acquire Start to begin counting your standard source Fig 2 Count Fig 2 until there are well defined peaks visible in the main window Choose Acquire Stop
24. m 1 4 Look at the spectrum you have acquired To change the display e g fill colors Par rat and Region of Interest shading choose Display Preferences and select one of the sime tenet options For this example we will select the Fill All option from the Preferences Sane ea submenu Fig 3 The resulting spectrum contrasts the background in this example Gener Keypad Full View Alt F Use the thumbnail feature in the upper right corner of the main spectrum window to move from one part of the spectrum to another by left clicking and dragging the mouse Fig 4 Fig 3 Fillet Peas v Fill Multiplet Composites Preferences d Points Fill ROI Spectrum Colors Peak Info Font Color 1 5 Locate a full energy peak a clear sharp peak in the main part of the MCA spectrum and use the Zoom feature to look more closely at the structure of the peak There are three ways to use the Zoom feature First try the menu approach Drag the thumbnail until the peak of interest is roughly in the middle of the thumbnail Click on the peak in the main MCA window Click Display Zoom In to move closer Fig 5 Continue to move closer by clicking the Zoom In control button on the GammavVision tool bar Fig 6 Zoom out from the peak of interest using the same methodology You can also use the functions keypad lt gt to zoom in and keypad lt gt to zoom out In most cases the Number Lock on the computer keyboard mu
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26. peak list and additional uncertainty components T Library peak matrix Confidence level e Choose the WAN32 Program under Analysis Method B C1 2 3Sigma e Add any additional uncertainty components under Additional Teh Error in the example we determined that the volumetric Pa ay testes rete eau measurements of our samples contributed a 2 uncertainty File Froese component to the total uncertainty You may add a Random Progam CAWINNT NOTEPAD EXE Browse component in the Additional Error CRepotiwrterr Browse e Complete the rest of the form as shown in Figure 40 Note There are four analysis engines included in Cancel Her GammavVision Although these analysis engines incorporate Fig 39 the same fundamental constants and decay equations each program treats the sample analysis differently The WAN32 Analysis Options KE analysis program is a good choice for simple analyses with a Sample System Decay Report Analysis AConections Isotopes Additional Error Systematic Analysis Method Programm relatively small number of nuclides For a more detailed description of the GammavVision analysis engines consult the WANS Analysis 2 000 Es GammavVision 32 V5 2 Users Manual ral cat ee 2 15 The Corrections and Isotopes tabs will not be needed peee fico a for this analysis the check boxes should be left unchecked Analysis Peak Cutoff f 00 0000 a True Coincidence D Correc
27. py analysis software Ge Detector GEM 100 GEM100 High resolution gamma ray detector Vertical Cryostat CFG PV 1 Cooling unit amp housing for detector 30 Liter Dewar DWR 30 Liquid nitrogen LN holding tank Lead Pb Shielding NA Pb bricks with copper liner Digital Spectrometer DSPEC PLUS Digital soectrometer and MCA contains HV bias supply for detector and Ethernet Computer interface Interface ETHCBL1 or ETHRJ45 Ethernet connection 10Base2 coax and 10BaseT RJ 45 to coax converter Computer NA Windows 98 Pentium 233 64MB Memory Calibration Source NA 2 L Marinelli Beaker geometry purchased from Analytics Inc Atlanta GA 2 L Marinelli Beaker NA Model 138 G Purchased from GA MA Associates Miami FL Using This How To Guide Information in this How To Guide is restricted to the most relevant tools needed to begin using your system Calibration basics theories and fundamentals are touched on only to make clear the purpose of a given task There are a number of important steps required for an accurate calibration By following this How To Guide you will familiarize yourself with these steps and the steps needed to calibrate your system for almost any sample matrix and geometry In the example exercise we highlight the features of GammaVision needed to begin analyzing samples quickly We assume that your system is powered up and connected to a compatible PC and you have correctly installed the GammavVision software In the exampl
28. s called a spectrum displayed as counts in channels in the MCA emulator window of GammaVision As pulses are received and processed GammavVision continuously shows the resulting spectrum Since the system has no advance knowledge of the energy of the incident photons an energy calibration is performed to assign the correct energies to appropriate channel numbers The energy calibration is performed by counting a standard source with known nuclide energies and instructing GammaVision to define channel numbers in terms of known energies This information is then used to evaluate unknown spectra Efficiency Calibration Only a fraction of the photons emitted from your sample will be registered as counts This fraction known as the efficiency is primarily a function of the energy of the emitted photons source geometry size of the detector and sample composition The efficiency is determined by counting a standard source of the same composition and geometry as your samples The standard source should consist of a suite of nuclides with energies that will include all nuclides of interest for your measurements In our example we will use the auto calibration feature of GammaVision to calibrate energy and efficiency of the system Peak Width Calibration The width of gamma ray peaks depends upon a number of statistical uncertainties involved in the processes of collecting and transmitting the gamma ray signal to the MCA Knowledge of the change in pea
29. st be enabled to use the keypad features Note As mentioned above an important parameter in accurate gamma ray measurements is the shape of the full energy peaks In order to correctly portray the peak width the transformation of pulses to counts in the MCA must be optimized This is accomplished manually by adjusting the pole zero feature in the system GammaVision automates this procedure using a computer algorithm located in the MCB Properties submenu in the main Acquire menu In this example a DSPEC Plus digital spectrometer is used 1 6 To optimize the shape of the gamma ray peaks for your system choose Acquire MCB Properties and click the Amplifier tab Adjust the Fine Gain to 0 67 and choose X1 for the Coarse Gain Fig 7 Click the Optimize control In a few moments the computer algorithm will automatically adjust the pole zero feature of the DSPEC Plus You will be alerted when the process is complete lia Arua hate oda naa ny wit wf lea are Im 2 TIE Bera tara 316915 Hut fo cep Nl Properties About Note Inspect closely one of the full energy peaks by using the Thumbnail and Zoom In features as described above A well shaped gamma ray peak will be gaussian in shape roughly symmetric about the centroid The base of the peak will be slightly higher on the low energy side of the peak due to a phenomenon known as Compton Scattering For a full explanation of this phenomenon consult the texts in the Ref
30. tion Peak Stripping Library Based D Manual Based 2 16 Since each sample is a slightly different volume not necessarily the same as the standard source the sample volume must be input This may be accomplished by using the Ask On Start or Ask On Save Options 2 17 To instruct GammaVision to ask for the Sample Volume when the user Saves the spectrum such as at the end of Second Library Browse Third Library Browse Directed Fit T the acquisition choose File Settings Fig 41 and check the ce Sample Size checkbox under Ask On Save Options Fig 42 Fig 40 This will ensure that a value is input for this parameter for every sample and File Cee General Export Import Directories allow the user to create a template useful for many samples N Recall Save File Format f Integer Chni Uncheck the Sample Size for now we Save will use the Ask On Start Option in Step Save s Ask On Save Options l Sample Description j meters Pond B Sept 2000 Sampling 3 instead Eel FF Sample Size hao L 2 18 Check Integer Spc under Save siete C Collection Date 9 21 00 Time 00 00AM File Format The Integer Spc format Ea Sample Stat Date 12 8 00 Time E3714AM should be used in most cases Consult Sample End Date 2 8 00 Time 297 14 AM the GammaVision 32 V5 2 User s Ext gL Gi Manual for a des
31. ty to create many custom application analyses The software includes four analysis algorithms each with a unique capability For this How To Guide we will use the WAN32 analysis program For a description of the analysis programs included in GammavVision please consult the GammaVision 32 V5 2 Users Manual GammaVision assembles the important parameters of gamma ray analysis in one convenient Windows dialog environment called the Sample Type in most cases a template is needed to allow the Operator to create one analysis for many samples The parameters that often require customization include e Calibration e Peak Library Data e Report Output Requirements e Decay Corrections e Method of Peak Analysis We will use the Sample Type environment to create a template to analyze 2 L water samples These samples were collected at varying depths O to 9 m from the water column of a small lake in the Southeastern United States 2 1 To begin create a library which includes Load Library File BES only the nuclides that we are interested in eaa lookin Sue Ff reporting for our analysis From the main F a ME Liz MCA window in GammaVision choose eel i Ra Library Select File Fig 28A List 3 EES suspect 2 2 Browse to the User Fig 28A directory choose the Calib library and click Open salar eal O C Fig 28B eka as ner 222 Edit animnavision Edito 2 3 Choose Library Edit List GammavV
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