"user manual"
Contents
1. CANBERIRA DETECTOR SPECIFICATION AND PERFORMANCE DATA AFTER REPAIR Specifications Detector Model GR2019 Serial number b 85535 Cryostat Model 7500SL Preamplifier Model 2002CSL Cryostat description or Drawing Number if special Vertical Dipstick type 7500SL Physical Characteristics Geometry Coaxial one open end closed end facing window Diameter 46 5 mm Active volume es E Length 51 mm Crystal well depth mm Distance from window outside 3 mm Crystal well diameter mm Electrical Characteristics Depletion voltage 34000 Vde Recommended bias voltage Vde 24500 Vde Leakage current at recommended bias 0 01 nA Preamplifier test point voltage at recommended voltage 1 0 Vde Resolution and Efficiency after repair With amp time constant of 4 Hs Tsotope Co Co Energy keV 122 1332 839 178 Peak Compton 50 8 1 Rel Efficiency 17 4 eo te Tests are performed following IEEE standard test ANSI IEEE std325 1996 Standard Canberra electronics used See Germanium detector manual Section 7 Ay pte fa F ze Tested by peg Date February 9 2004 fa d Approved by Date February 9 2004 CANBERRA Semiconductor is an ISO 9000 certified company GDAME008 E 19 04 01 IA Figure 8 Detector specification for DET_2 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 A detector will be damaged if it is allowed to warm up whilst2. Pulse shape overshoot undershoot and correct return to the baseline This is adjusted by the Pole Zero control which is below the shaping zs control on the Amplifier It is a recess in the panel marked PZ Observing the shape of the waveform and rotating the PZ adjuster left and right with a precision screwdriver reveals that the pulse can be exaggerated in a positive and negative manner When the pulse base assumes as horizontal a shape as possible then the Pole Zero is correctly set A small change in the fine gain will not change Pole Zero but when setting up a new detector or if the coarse gain on the amplifier is changed the Pole Zero should always be checked The pulse has now been optimised and will produce the best possible analyses for the given equipment 11 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 8 PC and software overview Once the pulse has been optimised the next step is to perform an energy calibration This is done through the applications software loaded on the PC Genie 2000 Version 2 1 Genie 2000 gamma analysis software allows not only energy calibration but gamma spectrum analysis background subtraction reference peak correction efficiency correction including the LabSOCS geometry composer nuclide identification and quantification interference correction weighted mean activity and Minimum Detectable Activity MDA calculations cascade summing corrections
3. parent daughter decay correction and reporting Genie 2000 also has an add in Quality Assurance package Details and step by step instructions to using this software can be found in the Genie 2000 Operations Manual LabSOCS Calibration Software Manual and the QA Software Users Manual There are several sub menus within Genie 2000 found within the start up menu 8 1 VIRTUAL DATA MANAGER The Virtual Data Manager controls the inter process communication within Genie 2000 and connects each Genie 2000 functionality It is automatically booted on PC start up cannot be altered and should not be closed as any acquisition in progress will be lost 8 2 MCA INPUT DEFINITION EDITOR The first step in using a Genie 2000 system is to create at least one MCA input definition MID so the system knows what kind of MCA is installed or connected to the system For most systems the Input Definition can be set up quickly and easily by using the MID set up wizard For more complex systems there is a MID editor available to configure the input definition Unless a new detector or MCA is being set up there is no need to edit a MCA file 83 MID SET UP WIZARD The MID set up wizard is adequate in most cases to set up the MCA Input Definition Step by step instructions on how to set up a MID can be found in the Genie 2000 Operations manual pages 23 27 Once the new MID is set up it will be automatically loaded into the MCA Runtime Configuration Database and th
4. Absorber2 0 Source Detector Figure 12 LabSOCS simplified beaker template form Canberra Industries Inc 2002 18 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 To set up an efficiency calibration for a spectrum go to the Calibrate menu and select by ISOCS LabSOCS This will display the select input file box Click Run Geometry Composer and select the simplified beaker template Figure 12 Select a detector from the drop down list and this will build the detector specific information into the model Enter the physical dimensions and parameters of the geometry using the template diagram in Figure 11 which will describe the source and its relationship to the detector Enter the density and material of the beaker and the sample either using the list of materials or by constructing a chemical formula of the composition in MuEditor Figure 13 Double clicking on any of the materials in the Material Library list will bring up a box containing composition information for that material Je Editor of mu library d genie2k isocs data parameters mu04_8ib txt y x m Chemical Formula Composer agdas New Substance Composition Add As r Material library Component Component Balance Allowable Addition 100 000 Dea Component Double click for Info Formula Clear B EI p Si ae Mass _ percentage Element xX n 1 2 atom ratios gt F
5. amp cooling MCA Detector PC with GENIE 2000 Software amp QA Figure 2 Diagrammatic representation of gamma spectrometer system Not to scale The detector is held vertically above the liquid nitrogen dewar by means of locking screws either side of the copper rod which is immersed in the liquid nitrogen The position of the detector s upper surface is such that it is in the most central position achievable within the lead castle This castle or shielding is designed to reduce the influence of background radiation and improve the detection capability such that relatively small low level samples can be counted The shield is made predominantly from lead as its high density and high z value make it a good absorber of background radiation A 10 cm thickness of lead is commonly used as this provides the optimum shielding Figure 3 The radiation interacting with the shield induces X ray fluorescence in the Pb giving an additional source of background counts This is overcome by the use of a graded Pb Cd Cu shield in which a Cd lining is used to absorb the Pb X rays and an inner Cu lining to absorb the Cd X rays Figure 4 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 Figure 3 Outer lead shielding Figure 4 Inner cadmium copper shielding The high voltage power supply the amplifier and the multi channel analyser MCA are housed in and powered by a Nuclear Instrument Module relay rack NIM Bin The electrical p
6. and place it in the source spacer on the centre of the detector Close the castle lid Connect the amplifier to the Picoscope Oscilloscope using the provided BNC cable via the Unipolar Output socket on the front of the Amplifier to input A on the Picoscope Select the appropriate polarity given on the detector certificate on the Amplifier controls Select the Pico icon on the desktop of the PC The Picoscope front end should display a representation of an oscilloscope with X and Y axes and due to the systems intuitive software pulses from the Amplifier should be displayed Alternatively a stand alone oscilloscope could be used to assess the pulses If the oscilloscope is observed whilst switching between the various y S settings on the shaping control on the amplifier the step between the leading edge of the peak and the 10 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 trailing edge can be minimised Adjustment of the shaping time constant to the recommended shaping time from the detector certificate 4 u sec should achieve best results 7 2 POLE ZERO It is also important that the pulse returns to the baseline without over or undershoot The correct position as well as incorrect positions is shown in Figure 10 Over Compensation Pole Zero Correct 50 mV div Under Compensation 20 psec div Figure 10
7. 18101e 002 4 0 1400 00 9 419 7e 003 40 2000 00 7 20292e 003 4 0 Cross over Comment IRONSTONE_10 FE_HIGHORG_DET_1 Description ISOCS IRONSTONE_10 FE_HIGHORG_DET_1 Eff Geom ID 10_HIGHORG_DET_1 coca o Figure 14 Efficiency results display O Canberra Industries Inc 2002 To see the efficiency curve Figure 15 click show Efficiency Calibration Curves g x Curve High Energy e Dual Linear Empirical Interpolated Low Energy Measured Scale C Linear Log Order of low mde So g E Order of the 10 100 1000 mm Pre EE Energy ke Peak E Drop Pk Datasource E E 009 Data Sample Spectra Files lronstones J687_Det1_Full_pot CNF InfEff 1 15 e 002 7 274e 001 In E 1 731e 001 In E 2 1 802e 000 In E 3 6 990e 002 In E 4 DK Cancel Help Print Figure 15 Efficiency calibration curve Canberra Industries Inc 2002 To further check the efficiency points are well fitted click on List Pks This will list the energy of each peak and the percentage deviation from the efficiency curve Ideally the percentage deviation should be zero or close to it If this is not the case go back to the efficiency results and insert a crossover point at around 150 200 keV This should improve the fit of the curve and reduce the percentage deviation Once this is saved that efficiency will apply to the spectrum open in Genie 2000 It is als
8. is not one them make one with the certificate file editor The calibration box will appear on your screen On the 60 second calibration spectrum that was collected move the two markers to surround one of the easily identifiable peaks Click on markers and the peak between the two markers will be assessed and registered in the calibration Do this to one other easily recognisable peak so that two points are registered in the calibration Then click on Auto for the rest of the peaks in the spectrum to be registered Click next on show An energy versus channel number graph will be shown which should be linear and through the origin Now the energy calibration is complete The Energy recalibration option from the calibrate menu allows quick recomputation of the energy vs channel curve It is useful to carry out this check regularly to maintain correct energy calibration 16 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 9 2 EFFICIENCY CALIBRATION 9 2 1 Efficiency Efficiency calibration can only be carried out once the energy calibration is complete The absolute photopeak efficiency is outlined in the equation below Counts per second observed in the spectrum photopeak Ey Efficiency Ey lt lt Emitted gamma rays per second by the source Ey Two factors determine the absolute photopeak efficiency of a system 1 Geometry Geometry means the distance between the detector and the
9. ml polycarbonate pots with a screw lid to avoid leakage These pots are supplied by Lab 3 1 Dragon Court Crofts End St George Road St George Bristol BSS 7XX Tel 0870 4445553 And manufactured by Bibby Sterilin Ltd Stone Staffs STIS OSA Each sample pot is placed in the appropriate sample holder and placed over the detector The sample holder merely holds the sample in the centre of the detector so that the pot is placed in exactly the same place each time This is particularly important when using the LabSOCS calibration The sample container still lies directly on the detector 21 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 10 2 ANALYSIS SEQUENCES Analysis sequences are used to automate each stage of the analysis and are very useful when running batches of samples Under the Execute Analysis sequence there are several analysis sequences for different sample geometry different detectors the QA source and standards for each matrix For example there is the RR_water_DET_1 analysis sequence which is matrix specific to 250ml pots of water and detector specific to DET_1 By selecting this you will be prompted to edit the sample information and select an efficiency file Once these have been completed the acquisition acquire start button can be hit The acquisition runs until it reaches the preset live time or until it is manually stopped The analys
10. 04 28
11. A software The definitions of the items to be tracked can be specified through the Add defs menu These definitions include peak search Nuclide Energy line Generic background or manual options Extract is also under the Add defs menu and can be used to extract the definitions and set up of a current database to create an identical database This would be useful for example when making up three databases for different sample matrices on the same detector For the QA source there is a database to monitor FWHM Activity and peak energy of Am 241 Cs 137 and Co 60 on each detector Likewise the water sediment and vegetation standards each have a database for each detector and are monitored in a similar way Databases for each sample matrix on each detector monitor the Co Minimum Detectable Activity as this is the main nuclide of interest for our most significant current customer These QA databases for standards and the QA source can be found in W GRF GammSpecLab QA Once these databases have been established every analysis is automatically transferred during the analysis sequence to the correct QA database This therefore collates the data runs the QA algorithms and flags up warnings if the data fails the pre determined criteria 113 LIMIT CHECKING There are broadly two types of limit checking in the QA software Boundary tests or Statistical tests Boundary tests issue a warning if a value such as the centroid of a peak d
12. British Geological Survey NATURAL ENVIRONMENT RESEARCH COUNCIL Gamma Spectrometry Laboratory User manual Geoscience Resources and Facilities Directorate Internal Report IR 04 174 BRITISH GEOLOGICAL SURVEY INTERNAL REPORT IR 04 174 Gamma Spectrometry Laboratory User manual C Emery M Strutt Key words Gamma spectrometry LabSOCS QA Bibliographical reference EMERY C STRUTT M 2004 Gamma Spectrometry Laboratory User Manual British Geological Survey Internal Report 1R 04 174 28pp O NERC 2004 Keyworth Nottingham British Geological Survey 2004 BRITISH GEOLOGICAL SURVEY The full range of Survey publications is available from the BGS Sales Desks at Nottingham and Edinburgh see contact details below or shop online at www thebgs co uk The London Information Office maintains a reference collection of BGS publications including maps for consultation The Survey publishes an annual catalogue of its maps and other publications this catalogue is available from any of the BGS Sales Desks The British Geological Survey carries out the geological survey of Great Britain and Northern Ireland the latter as an agency service for the government of Northern Ireland and of the surrounding continental shelf as well as its basic research projects It also undertakes programmes of British technical aid in geology in developing countries as arranged by the Department for International Development a
13. IM Bin followed by the HVPS A red LED should light up to indicate either positive or negative bias The LEDs are above and below the voltmeter If the certificate polarity agrees with the illuminated LED it is not necessary to change the bias polarity If however the polarity is different to the bias stated on the detector certificate the HVPS must be corrected To do this the HVPS and NIM Bin must be switched off The HVPS module should be removed from the NIM Bin and the left hand cover plate from the module should be removed by unscrewing the 5 screws With the module on its side locate the OUTPUT label Between this and the back of the unit should appear the word Positive or Negative on a 10 cm long plug orientated left to right with the polarity printed on it To change the polarity rotate the retaining plate in a clockwise fashion withdraw the plug away from the Output label and replace the plug with the correct polarity facing upwards Replace the retaining plate the cover and the screws The polarity should now match the polarity stated in the detector certificate Checking the NIM Bin is switched off place the HVPS back into the NIM Bin and connect the black BNC cable between the High Voltage J1 socket at the rear of the module and the BNC connector on the detector Only one connector fits and is attached to a black cable from the preamplifier Once this is achieved the connection should be covered with th
14. NUAL CONFERENCE ON BIOASSAY ANALYTICAL AND ENVIRONMENTAL RADIOCHEMISTRY NOVEMBER 15 19 1998 ALBUQERQUE NM BRONSON F L VENKATARAMAN R YOUNG B 1998 OPTIMUM SIZE AND SHAPE OF LABORATORY SAMPLES FOR GAMMA SPECTROSCOPY WITH VARIOUS SIZE AND SHAPE GE DETECTORS PRESENTED AT THE 44 ANNUAL CONFERENCE ON BIOASSAY ANALYTICAL AND ENVIRONMENTAL RADIOCHEMISTRY NOVEMBER 15 19 1998 ALBUQERQUE NM BRONSON F L VENKATARAMAN R 2000 VALIDATION OF THE ACCURACY OF THE LABSOCS MATHEMATICAL EFFICIENCY CALIBRATION FOR TYPICAL LABORATORY SAMPLES PRESENTED AT THE 46 ANNUAL CONFERENCE ON BIOASSAY ANALYTICAL AND ENVIRONMENTAL RADIOCHEMISTRY NOVEMBER 12 17 2000 SEATTLE WASHINGTON CANBERRA INDUSTRIES 2001 CANBERRA GERMANIUM DETECTORS USERS MANUAL CANBERRA INDUSTRIES 2002 MODEL S505 QA SOFTWARE USERS MANUAL CANBERRA INDUSTRIES 2002 GENIE 2000 OPERATIONS MANUAL CANBERRA INDUSTRIES 2002 GENIE 2000 CUSTOMISATION TOOLS MANUAL CANBERRA INDUSTRIES 2002 MODEL S574 LABSOCS CALIBRATION SOFTWARE USERS MANUAL CANBERRA INDUSTRIES 2002 MODEL 573 S574 ISOCS LABSOCS VALIDATION amp VERIFICATION MANUAL DEBERTIN K AND HELMER R G 1998 GAMMA AND X RAY SPECTROMETRY WITH SEMI CONDUCTOR DETECTORS P51 60 NORTH HOLLAND GEHRKE R J AND DAVIDSON J R 2005 ACQUISITION OF QUALITY GAMMA RAY SPECTRA WITH HPGE SPECTROMETERS APPLIED RADIATION AND ISOTOPES VOLUME 62 MARCH 2005 PAGES 479 499 AVAILABLE ONLINE OCTOBER 20
15. aintaining the nuclide libraries that are used for both qualitative and quantitative radionuclide analysis The standard library provided with Genie 2000 STDLIB NLB contains 109 nuclides and 511 energy lines which covers all of the commonly determined radionuclides In addition to this there are four master libraries containing about 800 nuclides and 31 000 energy lines It is also possible to customise a library from the standard or the master libraries This is useful when providing specific analysies to a customer 14 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 8 7 CERTIFICATE FILE EDITOR The certificate file editor creates and maintains copies of certificate files from the suppliers of certified radioactive standard materials e g a certificate file from a mixed radionuclide standard solution from the National Physical Laboratory These files are used to program efficiency calibrations when using the conventional radioactive standard efficiency calibration method New certificate files can be made by extracting correct information from nuclide libraries or from previous certificate CTF files 15 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 9 Calibration 9 1 ENERGY CALIBRATION The principle of energy calibration is to establish the correct relation between the energy of the gamma emission and the energy channel it is found in It is imperative that the system is properly ene
16. ality control Sample duplicates and blanks are also analysed within sample batches from customers these are quality control QC samples In addition Quality Assurance QA software is run on the system that can use the generated QC data and data directly from sample analysis 11 1 QA SOFTWARE BASICS The Quality Assurance QA package is compatible with Genie 2000 and allows you to interactively establish a database of key system performance parameters It warns you if over time the parameters drift outside the allowable warning and error limits that are set A comprehensive statistical analysis reporting and plotting facility is provided for tracking system performance and stability over time The software s audit trail allows verification of the systems performance Firstly System gain and the energy calibration are monitored by tracking the peak centroid location of one or more peaks commonly found in the samples or calibration standards This is done at BGS by counting a specially designed QA source consisting of point sources of Am 137Cs and Co once a week on each detector The spectra collected are then fed into the QA software and the peak centroids and Full Width Half Maximum FWHM are tracked The spectra collected from these 600 second QA source counts should be analysed using the analysis sequence DET_1_QA_ Count or DET_2_QA_ Count for analysis on DET_1 and DET 2 respectively System efficiency is monitored by periodic
17. ally counting a certified mixed radionuclide standard of known activity and monitoring the activity values for selected peaks A standard for each sample matrix is analyzed at the start and end of each sample batch or as often as the workload on the detectors allows The analysis sequences for DET_1 are as follows SED_STD_DET_1 VEG_STD_DET_1 Dilute_Water_DET_1 Full_Water_DET_1 for the sediment vegetation dilute and full water standards respectively Each analysis sequence sends the data from each analysis to the correct QA database An identical set of analysis sequences and QA databases are set up for DET_2 System background can also be tracked This is unlikely to be an issue in the Keyworth laboratory as the background should be low and should not change much It is however still worth analyzing the background regularly to check for example that no contamination event has occurred and also so that the most contemporary background is being subtracted from the sample counts A background spectrum for each detector is subtracted during analysis Temperature and humidity at the time of analysis can also be tracked but this must be manually input into QA and at present is not done in the BGS laboratory 23 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 11 2 QA DATABASES A database is set up to track each detector and each sample type separately A new QA database will automatically be created on starting the Q
18. ate the data values for bias and monotonic trends 11 4 REPORTING There are several reporting options including results from last test reports visual data plots and summaries of a variable s values over time deviation from the norm and alarm conditions Under the Results menu there are three reporting options Last measurement reports Full report or a bias summary which looks for a trend in the data of course there shouldn t be a trend Report templates can be customized through modification of an ASCII template 25 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 12 Further Information 12 1 EQUIPMENT AND SOFTWARE SUPPLIER CONTACT DETAILS Canberra Harwell Building 528 10 Unit 1 Harwell International Business Centre Didcot Oxfordshire OX11 OTA Telephone 01235 838 319 12 2 ONLINE INFORMATION Online product information and search facilities can be found at www canberra harwell com 12 3 CERTIFICATES AND DETECTOR SPECIFICATIONS All source certificates mixed radionuclide standard solution certificates detector specifications etc are filed in the top drawer of the cabinet in the laboratory 124 USER MANUALS The Canberra Harwell pdf user manuals are stored on the PC in the laboratory under D Genie2k pdfs docs The following paper copies of the user manuals are in labelled box files on the shelves in the laboratory E008 Equipment manuals e Can
19. berra Germanium Detectors Users Manual Contains technical information about equipment start up and running the system e Multiport II Multichannel Analyser Users Manual 26 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 Software Manuals Genie 2000 Read Me First Genie 2000 Operations Manual Genie 2000 Customisation tools manual Genie 2000 Canberra Harwell Training Course Notes QA Software Users Manual LabSOCS Manuals LabSOCS Calibration Software Users Manual ISOCS LabSOCS Validation and Verification Manual ISOCS LabSOCS Detector characterisation report Detector S N B02146 DET_1 ISOCS LabSOCS Detector characterisation report ACK 84038 Detector S N B 85535 DET_2 Verification of the ISOCS characterisation of the Canberra LabSOCS system for Harwell DET_1 12 5 BGS CONTACTS Dave Jones Cathy Emery Mick Strutt John Davis dgi bgs ac uk KW Room D007 Extn 3576 cemery bgs ac uk KW Room D008 Extn 3038 mick mvo ms KW Room D002 Extn 3304 currently overseas jrda bgs ac uk KW Room E205 Extn 3592 27 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 References ADAMS F AND DAMS R 1975 APPLIED GAMMA RAY SPECTROMETRY SECOND EDTITION PERGAMON PRESS ISBN 0 08 006888 X BRONSON F L YOUNG B VENKATARAMAN R 1998 MATHEMATICAL EFFICIENCY CALIBRATION OF GE DETECTORS FOR LABORATORY SAMPLE GAMMA SPECTROSCOPY PRESENTED AT THE AAT AN
20. ch have been supplied to BGS for each detector Calibrations can be performed for many different sample shapes from cylindrical objects viewed from end to Marinelli beakers The simplified beaker model is used in the BGS gamma spectrometry laboratory as it best describes the standard sample geometries used Figure 11 Validation testing of the laboratory geometries was accurate to within 4 5 standard deviation at high energies and 7 standard deviation at low energies These uncertainties are believed to be consistent with the errors inherent in calibrations with radioactive sources when the many variables involved are considered Bronson et al 1998 17 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 Picture Scale C Auto 1 1 side and bottom thickness Absorber s Figure 11 LabSOCS simplified beaker template diagram Canberra Industries Inc 2002 LabSOCS Template SIMPLIFIED_BEAKER Delete Help r Template Version Detector and End Cap _ r Geometry Information Jeone_or_cylinder none e Description none Save Data As User Comment leen D st Diam fo Length fo none m Set Sample via Dimensions Scale Dimensions Ze mm cm inch C Volume ml C Weight g C otm M Geometry Elements Dimensions m Density and Material lt Select from List Desorption d2 dz Jas as bien Material Call MuEditor L I 0 none Sample 0 Absorberl 0
21. cssccessccssccessee lS Figure 12 LabSOCS simplified beaker template form ENEE enen LS Figure 13 MULE EEN E Figure 14 Efficiency results display ccccccccsccccccsccccccsccsccsccccccssccccesscsssessss 20 Figure 15 Efficiency calibration CUrve c cceccsccccccscccccccccscccccesccsscsscessessseQ0 111 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 1 Introduction This document intends to inform the reader both generally about gamma spectrometry and more specifically of the system and procedures in place at the British Geological Survey gamma spectrometry laboratory Keyworth Gamma decay equipment specifications requirements and set up are firstly discussed Calibration for both energy and efficiency are outlined followed by acquisition and analysis Quality assurance procedures are then detailed and demonstrated 2 Gamma Decay Radioactive decay is a spontaneous process in which an unstable nucleus emits radiation in the form of a sub nuclear particle or a photon of electromagnetic radiation and is converted into a new nucleus of lower internal energy Radioactive decay involves a transition between a defined quantum state of the original nucleus and a defined quantum state of the product nuclide The energy difference between the two quantised levels involved in the transition is called the decay energy and is characteristic of that transition This decay energy appears as the kinetic e
22. de Libr ry editor beier geen A AA ADA a iS 14 8 7 Certificate EE 15 Cal Dra Ur Ee LO 91 Entro Ee 16 92 Efficiency Calibration ii al 17 10 Acquisition and analysis EE Al 11 10 1 Sample Ge ORIG TIES ches cece See se te ea Saal Sk eat E a A ean a 21 A A A A IO 22 10 3 REPO AAA SAVING ds ease 22 Quality ASSUTADCO orto astroa setea oO ote da eteevs ee eRe OS FEI e e TEE 23 ELA EE 24 11 3 Limit CHC CK tas 24 Le Repo ati i 25 12 Further Information ii o 20 12 1 Equipment and software supplier contact details 26 12 2 Online AA 26 12 3 certificates and detector speciticaonsss 3 E 26 12 4 ee 26 12 5 ee 27 E EN FIGURES Figure 1 Conductor Semi conductor and Insulator properties ccsccsecessscssscesed Figure 2 Diagrammatic representation of gamma spectrometer system enn Figure 3 Outer lead Shiela ine ti eege Figure 4 Inner cadmium copper Shielding ccsccsscccssccssccccsccsccccscccsscccssccsscceed Figure 5 Detector T DET Divina A AA AO Figure 6 Detector 24DET Lia A A Figure 7 Detector specification for DEI Leen Figure 8 Detector specification for DET_2 cccccsccccccscccccccccsccsccccccssccscesseee Figure 9 NIM Bin housing HVPS amplifiers and ADC MCA cccccseceeceecessceed Figure 10 Pulse shape overshoot undershoot and correct return to the baseline 11 Figure 11 LabSOCS simplified beaker template diagram cccs
23. e black plastic sheath on the detector bias cable The Amplifier 2022 should then be placed in the NIM Bin next to the HVPS Using the other BNC cable with the female connectors connect the detector signal output to the Amplifier ensuring that the LB1500 Cable Transformer is located between the unlabelled detector signal output and the cable This will only fit in one direction Connect the other end of the cable to the Input socket at the rear of the Amplifier module With the power still off connect the grey 9 way parallel cable between the detector and the Pre amplifier Power port at the rear of the Amplifier 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 6 3 POWER UP Firstly check all cables are properly connected and that all the connector sheathing is in place Observe the amplifier output with an oscilloscope The noise should be several hundred millivolts peak to peak with no detector bias applied The Pre amplifier Test Point Voltage from the detector Certificate should be noted 0 1 or 0 2 Vdc Locate the detector test point underneath the detector housing it is a small hole of approximately 3mm surrounded by a white plastic rim Using a multimeter place one terminal into this and the other to the castle frame A voltage close to the Pre amplifier Test Point Voltage should be achieved Switch on the NIM Bin at the mains and with the toggle switch on the right hand side of the bi
24. e is applied to a semi conductor at low temperatures no current will flow If however a gamma photon deposits energy in the crystal the resultant ionisation will result in promotion of electrons to the conduction band and a transient electrical pulse will be produced the magnitude of which will be proportional to the energy deposited in the crystal Germanium provides excellent properties for use as a gamma photon detector since it can be produced as very high purity intrinsic semiconductors in the form of large crystals Ion implanted electrical contacts are formed on the crystal which is contained under vacuum in a protective aluminium can The crystal is maintained at low temperature by mounting it on a cryostat containing liquid nitrogen with thermal contact between the crystal and the liquid nitrogen being established by a copper rod the cold finger 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 4 Equipment requirements and shielding The high purity germanium crystal in the protective aluminium can cooled via the cold finger by liquid nitrogen is attached to a series of electronic equipment that processes the signal a preamplifier an amplifier an analogue to digital converter ADC a Multi Channel Analyser MCA and lastly a PC This is shown below in Figure 2 Graded Pb Cd Cu Shield Detector amp Pre Amplifier Copper Amplifier High Voltage Power Liquid Nitrogen Dewar Supply supporting
25. e system is then ready to calibrate 12 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 8 4 GAMMA ACQUISITION AND ANALYSIS The gamma acquisition and analysis functionality is the backbone to Genie 2000 It performs many tasks 8 4 1 Energy calibration Using radioactive point sources with energies that span the full range of interest the relationship between the channel and the energy of the peaks is established This gives meaning to the spectrum and allows for correct identification of energy peaks and therefore of radionuclides Full energy calibration as well as quick energy calibration checks can be carried out see section 9 1 8 4 2 Efficiency Calibration Until recently efficiency calibrations at BGS were carried out using standards spiked with mixed radionuclides certified by the National Physical Laboratory They were prepared using similar matrices to the samples being analysed in the same geometries in order to maintain geometric consistency This was done via the gamma acquisition and analysis functionality by including the correct efficiency calibration from the certificated mixed radionuclide source within each analysis sequence This empirical form of calibration although accurate was time consuming if new sample matrices or geometries were analysed However BGS has now purchased mathematical efficiency calibration software LabSOCS This is also run through Genie 2000 Gamma spectrometry operates w
26. hase specifications and therefore the warranted performance of this detector are as follows Nominal volume _ ce Relative efficiency 35 Resolution 1 8 keV FWHM at 1 33 MeV ____ keV FWTM at 1 33 MeV 875 keV FWHM at 122 keV _ keV FWTM at_ Peak Compton 61 1 Cryostat well diameter ____ Well depth mm Cryostat description or Drawing Number if special Vertical Dipstick type 7500SL Physical Characteristics Geometry Coaxial one open end closed end facing window Diameter 60 5 mm Active volume tn EC Length 58 mm Crystal well depth mm Distance from window outside 5 mm Crystal well diameter mm Electrical Characteristics Depletion voltage 33000 Vde Recommended bias voltage Vdc 235000 Vdc Leakage current at recommended bias 0 01 nA Preamplifier test point voltage at recommended voltage 0 2 Vde Resolution and Efficiency With amp time constant of 4 us Energy keV FWHM keV FWTM keV Rel Efficiency Tests are performed following IEEE standard test ANSI IEEE std325 1996 Standard Canberra electronics used See Germanium detector manual Section 7 ae P 4 Date October 7 2003 Tested by F Approved by Y gt E Date October 7 2003 eo CANBERRA Semiconductor is an ISO 9000 certified company GDAME001 E 19 04 01 H i Figure 7 Detector specification for DET_1 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 DEI 2 c emety
27. igital Converter ADC functionality The PC is loaded with Genie 2000 software which fully supports and remotely controls the Multiport IT MCA Figure 9 NIM Bin housing HVPS amplifiers and ADC MCA There is also the option to attach an Oscilloscope or to use Picoscope software on the PC to check pulse shaping see section 7 1 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 6 Equipment set up and power up 6 1 DETECTOR SET UP AND COOLING Once the copper rod or cold finger is inserted into the dewar and the black collar at the top of the dewar is tightened the detector is then in place The dewar should be positioned beneath the castle so that the detector is placed as close to the centre of the castle as possible the optimum position for counting If the set up is from a warm start the dewar should be filled with liquid nitrogen and left for a minimum of 6 hours This allows the crystal to cool and stabilise Once the detector is cool and the green LED is visible on the Al can the detector is ready to have bias applied 6 2 ELECTRONICS AND HVPS With reference to the detector certificate of efficiency supplied at purchase establish the bias of the detector See Figures 7 and 8 Check that the power to the NIM Bin is off and Place the High Voltage Power Supply HVPS in the NIM Bin without the cabling to the detector Check the black voltage adjuster is set to 0000v and switch on the N
28. inal Material Composition Load into Density g cm3 jo library Name of the new substance funtited IN Comment Back to GC dialog Help Delete substance Figure 13 MuEditor Canberra Industries Inc 2002 Sample density can be calculated by Sample weight Sample volume and should be entered in the sample density box see figure 12 Give a description of the model in the Geometry information box as this will be the file name Once this efficiency model is saved and closed a Geometry Composer report will appear Click on the Check geometry validity icon and then on the generate efficiency points icon An efficiency file for that geometry has therefore been created Save and close the report and the select input file box will once again be showing From the drop down menu select the file needed the last one created will appear at the top of the list and click next The Select optional efficiency factor will be default set at efficiency again click next The efficiency results are then displayed Figure 14 19 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 Calibrate by ISOCS LabSOCS Efficiency Results x Efficiency Error Cross 100 00 3 76790e 002 100 150 00 4 08515e 002 100 200 00 3 65553e 002 8 0 Pe 300 00 2 79547e 002 8 0 500 00 1 88687e 002 6 0 Gina 700 00 1 47810e 002 6 0 1000 00 1
29. is sequence will then go through these stages e Peak locate unidentified second difference e Peak area Sum Non linear LSQ fit e Efficiency correction standard e Nuclide identification NID with interference correction e Detection limits Currie MDA e Reporting of each stage with header of sample information Analysis can also be carried out during acquire for example to check if a sample has reached a required MDA without disturbing the counting Analysis sequences are detector specific as the correct background from each detector should be subtracted from each spectrum There are also separate sequences for each geometry be it sediment vegetation or water to ensure the results are fed into the correct QA database Sample information is recorded both in Genie 2000 gamma acquisition and analysis and in a hard backed book in the laboratory There is one book per detector and it is vital that it is kept up to date 10 3 REPORTING AND SAVING Each spectrum collected is saved as raw data as a CAM File on the PC hard drive The report generated by each analysis is copied from the report window in Microsoft Word and saved Both the CAM file and the Word document from each sample are backed up onto the BGS network W GRF GammSpecLab 22 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 11 Quality Assurance Standards and certified reference materials are analysed at regular intervals to ensure good qu
30. ithin the bounds of extremely well constrained radiometric and physical processes such that these may be mathematically modelled Each detector has been thoroughly defined and LabSOCS modelled by the manufacturers so the exact parameters of each detector are known Each sample geometry and sample type model is set up in the Geometry Composer and the efficiency correction is then applied in the gamma acquisition and analysis window see section 9 2 2 8 4 3 Data acquisition Firstly a datasource must be opened From the Open datasource menu by selecting detector a list of the available detectors will be displayed Selecting for example DET _1 will open the control window for DET 1 By selecting Acquire start the data acquisition will be initiated on that current datasource At any time Acquire stop will stop the acquisition Acquisition will also stop when the preset time for the count was reached if it had been previously defined The pulses analysed by the MCA are proportional in size to the amount of radiation energy deposited in the crystal The total number of counts corresponds to the area under the photopeak In general the photopeak will lie on top of the Compton continuum which is generated by back scattering from higher energy gamma photons Adams and Dams 1975 13 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 8 4 4 Analysis of gamma spectra In order to analyse spectra a number
31. knowledgements Thanks are due to Canberra Harwell a Canberra Industries Inc subsidiary for their technical support and advice in particular to Ian Sinclair who provided training equipment checks and freely gave advice on a number of occasions David Jones of BGS gave not only support whilst the Laboratory was undergoing important changes he also helped to review draft chapters of this report Thanks also go to Jenny Cook John Davis and Simon Chenery all of BGS for their help and support Contents HOTEWOLK BET AAA AS NOAA A 1 bb amp N i Introd ctio ege du eggei A RT E E e E EEN Semiconductors and detection Of gamma rays ccecrcccssscccsssccssssccssssccsssscssssscesssscsssces 2 Equipment requirements and sShielding cccccssscssssscssssccssssscssssccsssscsssssccssssscsssssssee J Gamma spectrometry laboratory BGS Keyworth Detector specific information 5 Equipment Set up and power up cccconecmocconennecconnociccanenaniconecanacinnracacanconacacanenanonacaconacacinccanes Y DH JDEteCtorise Up and OO E A NA ES 9 6 2 Electronics and AV PS asc tee rat dees sartad EES E aa 9 63 POE ID EE 10 Pulse configuring for analysis oooooooossss LO Ti JP EE EE 10 K2 EG 11 PO and software OVEL VIEW AA deeg Sul Virtual Data E EE 12 8 2 MCA eegen 12 83 MID SETUP Wiat DEE 12 8 4 Gamma acquisition and analysis inci ici 13 8 5 Geometry COMIDO TEE 14 8 6 N c li
32. n Increase bias to 100 volts The noise at the amplifier output should decrease somewhat and the voltmeter should momentarily change before returning to its initial reading For detectors using positive bias the test point voltage change will go negative and for detectors using negative bias the test point voltage will go positive Increase the bias now to 500 volts The noise should be further reduced and the voltmeter should respond exactly as before Slowly increase the bias in 500 volt steps to the recommended value from the detector certificate observing the behaviour of the amplifier signal and the voltmeter after each increment The noise should remain constant after the depletion voltage is reached If the detector has just been cooled the system should be left to stabilise overnight as spectral drift can occur 7 Pulse configuring for analysis 7 1 PULSE SHAPING Pulse shape shaping time and best possible return to the baseline of the pulse is vital to achieve good resolution in the spectrum These are controlled by the amplifier Pulse shaping is important as long pulses would increase pulse pile up and therefore dead time A Gaussian shaped pulse is a good compromise between signal noise ratio and technical possibilities To achieve a pulse as close as possible to a Gaussian shape most amplifiers have 2 to 3 or more filters To asses the pulses produced by the detector select a source from the point source box e g Co
33. nd other agencies The British Geological Survey is a component body of the Natural Environment Research Council Keyworth Nottingham NG12 5GG T 0115 936 3241 Fax 0115 936 3488 e mail sales bgs ac uk www bgs ac uk Shop online at www thebgs co uk Murchison House West Mains Road Edinburgh EH9 3LA 0131 667 1000 Fax 0131 668 2683 e mail scotsales bgs ac uk London Information Office at the Natural History Museum Earth Galleries Exhibition Road South Kensington London SW7 2DE 020 7589 4090 T 020 7942 5344 45 Fax 020 7584 8270 email bgslondon bgs ac uk Forde House Park Five Business Centre Harrier Way Sowton Exeter Devon EX2 7HU T 01392 445271 Fax 01392 445371 Geological Survey of Northern Ireland 20 College Gardens Belfast BT9 6BS T 028 9066 6595 Fax 028 9066 2835 Maclean Building Crowmarsh Gifford Wallingford Oxfordshire OX10 8BB T 01491 838800 Fax 01491 692345 Parent Body Natural Environment Research Council Polaris House North Star Avenue Swindon Wiltshire SN2 1EU SS 01793 411500 Fax 01793 411501 www nerc ac uk Foreword This report intends to inform the reader generically about gamma spectrometry and more specifically of the system and procedures in place at the British Geological Survey gamma spectrometry laboratory Keyworth It is intended to be used for training of staff as a reference document for staff using the laboratory and to formalise the procedures in place Ac
34. nergy of the decay products and electromagnetic radiation Often the product nuclide is initially of higher energy than the ground state and undergoes a transition to a lower energy by the process of gamma decay The energy difference between the two states appears as a high energy photon of electromagnetic radiation known as a gamma ray eg B gt Lit gt Li 7 477 6 keV excited state ground state Gamma photon energies are typically in the range 20 keV to 2 MeV and they are characteristic of the nuclide undergoing decay or strictly the decay product It is this diagnostic capability that makes gamma spectrometry a viable technique and makes it the preferred option for the analysis of gamma emitting radionuclides Since gamma photons are uncharged they have a low efficiency for interaction with electrons with the result that gamma radiation is highly penetrating Unlike alpha and beta particles which transfer their energy to absorbers in many interactions gamma photons transfer their energy in a single photoelectric event or in a small number of scattering events Consequently almost all of the ionisation produced in the matter by gamma photons is secondary ionisation i e ionisation caused by the electrons ejected in primary interactions 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 3 Semiconductors and detection of gamma rays Semiconductor detectors have good absorption characteristics f
35. o saved as an efficiency calibration file so can be loaded for analysis of another similar sample of that geometry 20 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 10 Acquisition and analysis Once the amplifier shaping time and pole zero are satisfactorily set and the energy and efficiency calibration is complete analysis can begin To acquire a spectrum under the Edit menu click Sample info This will allow sample name ID weight and assay date to be edited The weight is important as the analysis results will be reported in Becquerels per gram of sample The assay date is also important as the software will decay correct back to the original sample date Once the sample information has been added an efficiency calibration can be loaded This is achieved by clicking the Load icon in the Edit sample information box The efficiency calibration file can be chosen from the list of existing calibrations or a new calibration can be made via the Geometry Composer see Section 9 2 2 10 1 SAMPLE GEOMETRIES Each sample type is counted in standard geometries and the correct efficiency calibration for this geometry sample type and sample weight is applied The standard geometries used are e Soil sediment and vegetation are analysed in 150 ml squat polystyrene pots with polyethylene snap lids These are ordered by the sample preparation facility at BGS Keyworth e Water is analysed in 250
36. of steps are carried out in this order detection of peaks determination of the energy of peaks determination of the peak areas peak area corrections for background and summing isotope identification using certified nuclide libraries activity calculation of isotopes and calculating of detection limits MDA These steps can be carried out individually or automated into analysis sequences see section 9 2 8 4 5 Reporting The analyst controls which stages of the analysis sequence are to be reported Again individual stages of analysis can be reported or each stage from an analysis sequence This is controlled through the analysis sequence by edit analysis sequence insert reporting By clicking on Set up Algorithm the stage of the analysis to be reported can be selected from the drop down box and output either to the screen or a printer 8 5 GEOMETRY COMPOSER The calibration algorithms in the LabSOCS calibration software require an accurate description of the counting geometry for each sample The Geometry Composer is a tool allowing the interactive definition of all geometry related parameters such as detector properties sample dimensions composition and densities Templates are provided within the Geometry Composer of many standard geometries and the simplified beaker template is used here at BGS see section 9 2 2 8 6 NUCLIDE LIBRARY EDITOR The Nuclide Library editor is for creating and m
37. or gamma radiation and produce very high resolution spectra This behaviour occurs because semiconductors have a very small energy gap between the valence and conduction bands Figure 1 ENERGY Conduction es band band band Valence __ A band Valence Valence band band Conductor Semiconductor Insulator Conduction band Small band gap energyA Conduction band permanently occupied permanently empty Figure 1 Conductor Semi conductor and Insulator properties Electrons in the conduction band are mobile and will move under the influence of an applied potential difference causing an electrical current to flow Crucial to the conduction process is whether or not there are electrons in this conduction band In insulators the electrons in the valence band are separated by a large gap from the conduction band in conductors the valence band overlaps the conduction band and in semiconductors there is a small gap between the valence and conduction bands This small conduction band gap energy Eg in a semiconductor is in the order of 1 eV which is small enough for thermal excitation of electrons to result in transitions from the valence band to the conduction band Therefore at room temperature the conduction band will be occupied and semiconductors will conduct electricity However at low temperatures the conduction band is effectively empty and semiconductors are insulators If a potential differenc
38. rgy calibrated to allow correct identification of nuclides The amplifier gain and the ADC zero define the final position of the peaks in the spectrum DET_1 has 16 381 channels spread over an energy range of 1 5 2831 keV DET_2 has 16 370 channels spread over a 1 2916 keV range The relationship between energy and channel should always be linear in these systems Both detectors are not calibrated for energies below approximately 50 keV due to noise X rays and high self adsorption at low energies With the amplifier shaping time and pole zero satisfactorily set the lower and upper energy ranges of the region of detection can be established and an energy calibration can be performed To energy calibrate the system count a multi line source or sources which give a good span over the energy range of interest For example a low energy emitter such as Am and in addition Co and Cs would give such a range of energies These sources are good for calibration as they have well defined singlet peaks without interference Collect a short spectrum of approximately 60 seconds Under the calibration menu select energy full This option gives a number of ways to energy calibrate by certificate file by nuclide list by calibration file or manually The best way is by certificate file as an accurate certificate can be created and used repeatedly so choose the by certificate file option Choose a certificate file from the list if there
39. rifts by more than X channels from where is should be located Statistical tests issue an investigate warning if a value varies by more than 2 sigma and an action warning if a value varies by more than 3 sigma from its historical norm from a normal value that you have specified or in the case of certified standards from certified value There are five types of test that can be performed Sample Driven Test This test specifies that the mean value used in the limit testing is to be based on historical values of the parameter being tested The calculation of the mean can also be limited to a specific time period if need be User Driven Test This test uses user defined mean and standard deviation entries for the statistical test Bias Value Test This is the type of testing to use when the parameter being measured has a known certified value for example standards and certified reference materials The known values are entered into the True Value text input field Boundary Test This test allows the establishment of absolute limits on the amount of variation acceptable in the parameter being tracked For example in the case of peak centroid more than plus or minus 2 24 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 channels from the expected location is not acceptable so Lower and Upper limits of 2 channels either side of the MCA expected channel number are entered Trend Test These tests interrog
40. sample the sample shape spatial distribution and density 2 Intrinsic efficiency of the detector The intrinsic efficiency of the detector is geometry independent and energy dependant Counts per second observed in the detector Intrinsic efficiency z gt Gamma rays which hit the detector This should not be confused with relative efficiency which is the efficiency of the Ge detector when compared to a 3x3 Nal detector IEEE Standards This is what is stated in the detector specifications see Figures 7 and 8 9 2 2 LabSOCS efficiency calibration As was discussed above geometry is very important when calibrating for efficiency Previously efficiency calibration was performed using standards which had similar density and z value characteristics to the samples and were spiked with mixed radionuclide solutions Recently there has been a move away from this approach towards mathematical modelling The LabSOCS mathematical efficiency calibration software uses a combination of Monte Carlo calculations and discrete ordinate attenuation computations At the factory the complete dimensions of each detector their mounting and hardware were placed into a MCNP a Monte Carlo technique model A large number of point computations were then run covering the 50 7000 keV energy range a 0 50m distance range and the 0 360 degree angular range This large set of detector specific data was combined into a series of mathematical equations whi
41. the bias is applied It is therefore imperative that the detectors be kept cool so the dewars are filled weekly with liquid nitrogen In practice a full dewar should last three weeks but 1t is not best practice to run the risk of allowing the detector to warm up There is a LED light on the outer Al can around the detector that is green when the detector is cool and red if the detector has been allowed to warm up It therefore should always be green Whilst filling the IN gas will flow out of the outflow pipe at the top of the dewar When the dewar is full liquid will spurt out of this outflow pipe into a small dewar positioned beside the detector This is a potential hazard that new users must bear in mind A set of 3 cables 2 coax with BNC connectors and a 9 pin serial connector are provided with the detector A further 50 ohm coax is required to connect the amplifier to the Multi Channel Analyser and another to hook up the oscilloscope to the amplifier for observation of pulse shaping The NIM Bin provides a large power supply and houses the various modules that may be used Figure 9 It should not be used for storing modules that are not needed as noise may be generated by a faulty module High Voltage Supply Modules Canberra 3106D for DET_1 and Canberra 3105 for DET_2 and Canberra 2022 Amplifier Modules are installed in this NIM Bin Also housed in the NIM Bin is the Canberra Multiport II Multi Channel Analyser MCA with Analogue to D
42. ulses produced by the crystal are amplified in the pre amplifier and shaped amplified and noise filtered in the amplifier The pulses are then converted to a digital signal by an analogue to digital converter ADC and processed in the MCA which analyses the pulses according to amplitude Proportionality is maintained in all of these processes so the pulses analysed by the MCA are proportional in size to the amount of radiation energy deposited in the crystal The PC which is interfaced with this equipment controls the acquisition analysis and QA software 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 5 Gamma spectrometry laboratory BGS Keyworth Detector specific information The BGS gamma spectrometry laboratory in Keyworth has 2 high purity germanium Canberra detectors Detector one DET_1 Figure 5 the newer of the two detectors is a 35 efficiency detector with a recommended bias voltage of ve 5000 Vdc full detector specification in Figure 7 Detector two DET_2 Figure 6 has a relative efficiency of 17 4 and a recommended bias of ve 4500 Vdc full detector specification in Figure 8 Figure 5 Detector 1 DET_1 Figure 6 Detector 2 DET_2 1R 04 174 Gamma Spectrometry Laboratory User Manual Version 1 0 CAN DETECTOR SPECIFICATION AND PERFORMANCE DATA Specifications Detector Model GC3518 Serial number b 02146 Cryostat Model 7500SL Preamplifier Model 2002CSL The purc
Download Pdf Manuals
Related Search