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Version 4.04.00 Princeton Gamma-Tech Instruments, Inc. Nuclear

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1. 119 Co ONDA e exe xar a xoda bara RERE 119 Appendix D Warning and Error Codes 121 Appendix E 1055 2 125 PPGT Introduction PRINCETON GAMMA TECH 1 introduction Welcome to the Quantum Family of Windows based MCA software for nuclear spectroscopy This set of software products provides analysts with powerful tools for accomplishing their analytical tasks This manual covers all the features of the following Quantum software variations QuantumMCA provides support for a broad range of hardware with tools for qualitative analysis QuantumGold adds full function quantitative analysis for nuclear spectroscopy to the features of Quantum MCA Quantum GeD includes both qualitative and full quantitative analysis features for germanium detec tors only lt does not support Nal 11 detectors or QCC mode QuantumGe is the same as Quantum GeD but does not include deconvolution analysis capabilities QuantumNalD has both qualitative and quantitative analysis for Nal detectors only QuantumNal is the same as QuantumNal but does not include deconvolution analysis capabilities 1 1 Conventions This manual uses the following typographic conventions File Exit Menu items are shown in bold mixed case with colons separating submenu items SHIFT Names of keys are shown in small capital letters CTRL SHIFT A plus sign between ke
2. y 110 195 o pojtea 10U SI wnyoads Mewud ATI 10N p sn 5891042121 Medij p sn jou saiualdijja Medij OMO son ea uin oH 94 L Indu yorum sayloads YUM One 0 L Aq Ho uo S lH dS eym 91 198 0 Indjno qolun S ll dS YUM p nunuo2 eu lul WOOD Winjuend 201 14 jqnoq sy atedueis Indu ue JO snyeis ou 195 buHiS sy b l i sy YlUMINdupxIIo HO JO UO 1ndino ue 19S Buuis sy b lu sy eym sy uolux indinolxz s s s jeue 5911 ul 8010 010 sn IM 5 Azeulud SU JOU JO 1 Bums sy Quagresnes 102 Quantum HapGT PRINCETON This page intentionally blank PPGT Analysis Algorithms 103 PRINCETON GAMMA TECH Appendix A Analysis Algorithms This document describes the analysis algorithms and the supporting general routines on which these algorithms are built The low level algorithms will be described first so that the description of the more complex procedures will be more straight forward A 1 Numerical Computation Routines Propagation of Errors Propagation of errors is a complex task in most analytical software When a value has an uncertainty associated with it and it is used in a calculation then the error must be computed for the resulting value In P
3. 75 6 HelpforHelp aa amp xu amp amp Bk ol do ii kond Ro dk ls i8 15 8 3 About MCA 75 9 Procedures 6 660454 585 5448 s s x ba REDE BO BBB 76 9 1 Loading a Spectrum 76 9 2 Saving a Spectrum 76 9 3 Adjusting the Spectrum Display Range 77 9 4 Creating Editing and Deleting ROIS 78 9 5 Identifying ROls 79 9 6 fc lifing Data xx s etek m sias paei a 80 9 7 Acquiring and Using a Background Spectrum 80 9 8 Setting Up Calibration 81 9 9 System Calibration Using the Auto Calibrate Functions 81 9 9 1 Csi37 Coarse Adjust 81 9 9 2 Fine Energy Calibration 82 9 9 3 Resolution Calibration 82 9 9 4 Efficiency Calibration 83 9 9 5 Calculating Detector Efficiency 84 vii vii Quantum WPGT PRINCETON GAMIMA TEGH 9 10 Creating a Calibration Standard 85 9 11 Manual System Calibration 86 9 11 1 Manual Two Point Calibration 86 9 12 System Calibration Using ROI Centroids 87 9 13 System Calibration Manua
4. 53 PRINCETON GAMIMA TEGH Table of Contents 6 3 3 Manual Resolution Calibration 54 6 4 Detector Parameters 55 6 5 Clearing Calibrations 57 6 6 TOOLSCUO s i e sira ii a a a EA ES ER MDB e E wea 57 6 6 1 Configuring the ToolSetup 58 6 6 2 Choosing Sensitivity and Limits Settings to Optimize Results 62 6 7 Selecting a Report Font 64 6 8 Selecting a Display Color 64 7 Analysis Tools 66 7 1 Spectrum Calculator 66 5 CONVOINNONS a sas x 2 900 2 EZ 2 vec DERA 5 67 7 3 ChanmnelData 68 TA ULU soyus pedradas m E 68 z BOLDeAIS 62 655646 oot 24 Bo mens E E 68 7 6 Peak Search 70 7 7 Peak Identify All Quantum Software 71 7 7 Repon Formals yi cas sardea azan dd xx A ar NA lm ws 71 7 8 Rapid Scan Quantitative Analysis Systems Only 72 7 9 Analyze with Deconvolution 73 7 10 Analyze ROI Directed 74 7 10 1 Saving Analysis Data with Spectrum 74 8 Help Menu 75 8 1 Contents
5. Maxl Click Max to display the full horizontal energy range of the spectrum 2 1 2 2 To control the expansion more precisely select the desired vievving region in the display using the right mouse button Bring the pointer to the start of the area of interest Press the right mouse button and drag out the gray area to the end of the desired range Release the mouse button Area selected painted with the right mouse button Quantum MCA Gold L x Fie Edit View Setup Analysis Tools Help muz Eu152 Edw Lin Log C Sait 28351 sss gla 1 Auto ax 419 hil L n GAMMALIB MDB pr 0 ELT 50000 Rate 34266 cps 2 Static 1 1049 1 x En n PAF chamei PE Comb lif nm DP a A Lo yl 26341 Start energy End energy To move the displayed range move the displayed r range RE gt E OO im 41 integeiif r FWHM m EEE Als nu FERA EE Channel 1259 Counts 233 ROI ROD Net Intega Displayed range If you have the auxiliary spectrum displayed the full primary spectrum will still be shown there Two red lines will mark the beginning and end of the energy range displayed in the main spectrum area To move just the position of the displayed range press the left mouse button on the square in the scroll bar above and drag to the new position To change the displayed range press the left
6. A 5 Quantitative Analysis Algorithms A 5 1 Analyze Rapid Scan The Rapid Scan algorithm is based on the Peak Finder and Peak Identify algorithms described above In Rapid Scan algorithm only those isotopes which have the USE flag in the radiations database set to true will be considered In the Rapid Scan algorithm the following computations are made 1 The smoothed background spectrum is subtracted channel by channel from the data 2 The Peak Finder is run to find any peaks in the spectrum if no ROIs are set or if the prompt Use Current ROIs is answered no ROlupdate is run to get a complete set of values for the QROI structures Peak Identify is run to determine which of the peaks in the spectrum belong to which iso topes The activity for each line is calculated according to the equations below The total activity for the sample is calculated as described below 110 Quantum PP GIT PRINCETON GAMIMA TEGH 100N 5 Activity 725 where the units are Bq FYL 100 2 71 4 65 _ K MDA Dis ao FYL Here F again represents the detector efficiency in percent which requires the normalizing factor of 100 in the numerator Y is the theoretical intensity of the line as given by the database and Lc is the elapsed live time of the sample spectrum is the continuum background count The A represent the activities calculated for each line in the spectrum which has been identified as belonging to an isotope in the
7. 8 2 Help for Help Selecting this menu option displays information about how to use Help 8 3 About MCA Check here to find the version number for your PGT Quantum MCA software 76 Quantum PGT PRINCETON GAMMA TECH 9 Procedures This section of How to procedures covers most common operations There are references to impor tant sections in the manual rather than detailed explanations of all the options 9 1 Loading a Spectrum Section 3 1 The File menu has three options for loading a saved spectrum from disk Section 3 4 page 31 File Load to Buffer puts the selection into the first empty memory buffer The spectrum and all its calibrations are loaded into that buffer File Load Spectrum Data Only puts the selection into the current primary spectrum memory The spectrum and its calibrations will overwrite the current data If the primary spectrum is con nected to a Live device the spectrum to be loaded must be compatible with the device you are try ing to load to Specifically they must be of the same type and the device must support enough ADC channels to load the data You will also be warned that device parameters and calibrations will be replaced After making the selection the Load Spectrum dialog box will appear T Zi nucisar specta vil El alee Select the directory folder using the E a drop down menu in the top field 2 1037 1 ane E 2 1060 1 ans Only the PGT file format
8. 2 3 3 ADC Controls The first set of ADC controls affect the digital interface between the amplifier and the ADC ADC Gate Mode Dead Time Mode Normal Anticoincidence Simple Busy Lowes Coincidence Gedcke Hale External C Off z Dead Time Input Polarity 1 Pileup Reject Input Gate Input Pol Gate Input Mode C Negative Positive Off on Peak Deteet Pol Negative Level Busy Dead Output Polarity E Pileup Rei Input Pol Negative Positive EdgeSens Negative Positive Negative Positive Positive lu The ADC gate mode gate input polarity and gate input mode should be set to correspond to your amplifier The most common settings are Anticoincidence Positive and Level Sensitive The dead time mode may be selected from any of the available settings Consult your ADC manual to find out the differences between the supported methods There may be differences in the implementation of these methods even when the documentation calls them by the same name The dead time input and output polarity should be set to correspond to your amplifier Likewise the pileup rejector input should match the output of your amplifier or should be turned off if it is not connected Some devices provide an ability to store a count of the pulses above the ULD in the last channel You may choose to do this by selecting place in last ch
9. ID File Name or Device Contains information about memory contents If an ID label was entered it is displayed If the spectrum was saved or loaded from disk the associated file name will be shown If the spectrum is live the MCA device on which data was taken will be shown Each of the four possible states of a memory has different consequences Empty Indicates a memory that is not in use and cannot be selected for dis play until a spectrum is loaded into it Static Designates a memory containing a spectrum loaded from disk It can not be used for data acquisition None of the setup parameters asso ciated with this memory can be changed Live Indicates a memory connected to a live device Data can only be acquired into a live memory Failed If a device in the hardware search configuration does not respond at startup then its state when the program last exited will be restored and the memory flagged as failed You cannot collect data on a Quantum WPGT PRINCETON GAMMA TEGH failed device A failed device will be restored to Live if it is found the next time the software is started 1 7 1 1 Freeing a Memory Free Selected Free All B To free a memory select it by clicking on its Memory button State and ID will tum red and click the Free Selected button The memory is now available for future use You can also click the Free All but ton to free all static memories at once You cannot clear the primary memory th
10. The easiest approach to system calibration is with the Setup Auto Calibrate functions 9 9 1 Cs137 Coarse Adjust To do an initial linear 2 point adiustment of the coarse and fine gains and the bias voltage you must have a Cs137 source 1 For a new system or when the system has changed select Setup Auto Calibrate In the control panel select Setup Calibration Setup Place the Cs137 in the usual source position for your detector Section 6 2 3 Select Setup Auto Calibrate Click the Cs137 Coarse Adiust button Spectrum collection vvill start automatically and the electronics adiusted as needed You will be asked if you wish to do an Initial Setup You must do this the first time but if your setup has not changed you can then answer No the next time The coarse adiustment will then take just 30 60 seconds 4 If a quadratic calibration exists for this system you will be asked if you want to replace it with the linear calibration Unless your system has changed answer No You may save the spectrum if you wish to keep a record as part of the daily audit information 82 Quantum PGT PRINCETON GAMIMA TEGH 9 9 2 Fine Energy Calibration The Fine Energy Calibration requires a source with at least five lines covering the energy range of interest For quantitative analysis with QuantumGold systems the source must be a calibrated stan dard so that an efficiency calibration can also be done Collect the spectrum or load the
11. The entire family of PGT Avalon software products store spectral data in a common format in a binary file with the ANS extension This file format consists of four sections a a 1536 byte header contain ing all of the setup and calibration information b the data stored as an array of long integers c a set of ROI descriptors one for each ROI defined and d a set of ZAF data blocks containing analytical information for each element analyzed The details of each section are discussed below C 1 PGT Spectrum Header The 1536 byte spectrum header contains all of the information necessary to process a spectrum for quantitative analysis or the circumstances under which it was acquired The structure of the header is shown below Type MaterialStruct 36 bytes MtlKey As Integer MtlName 0 To 9 As Byte z 1 To 3 As Integer f 1 To 3 As Single Density As Single pad 0 To 1 As Byte End Type ANS Header Visual Basic Version Rev 4 Member Byte Range Description Type ansheader rev As Integer 4 0000 Revision Code General Information id 0 To 71 As Byte 0002 Spectrum id RESV0O074 0 To 5 As Byte 0074 General reserved area alignment StartDate As Double 0080 Time in Windows Format Acq First Started StopDate As Double 0088 Time in Windows format Acq Last Ended Status Information ElapsedRT As Double 100961 Elapsed real time in sec XXX XX ElapsedLT As Double 0104 Elapsed live time in sec XXX XX Elap
12. directed quadratic calibration PPG T Procedures 87 PRINCETON GAMIMA TEGH 9 12 System Calibration Using ROI Centroids Manual calibration can be performed by using the centroids of the ROls in the spectrum There should first be a coarse linear calibration either by the Manual Calibrate Two Point method or the Auto Calibrate Cs137 Coarse Adjust procedure 1 After collecting the spectrum of a known source with at least five lines that span the energy range of interest make sure ROls are placed on the peaks 1507 2 Select Setup Manual Calibrate Energy by ROI Centroids A listing of all the ROls in the spectrum will be displayed Ea Manual Multi Point Calibration File Centroid Gross Standard chn cnts kev Err 27 089 120 1 20 363 800 1 10 124 300 1 2 931 000 7853 2 265 100 5 2 920 0001101 Enter Energy of Each Line to be Included in Calibration ROI Energy Linear Previous Next 1403 0 Execute Previous e Quadratic Enter Energy 3 Inthe Manual Multi Point Calibration list select each peak you wish to use in the calibration and enter its true energy You can select a line either by simply clicking on it or by pressing the Next or Previous buttons 4 When all of the energies have been entered select either Linear or Quadratic The latter will give more accurate results 5 Press Execute The errors between the standard values and the new calibration will be dis play
13. ground contributes to the spectrum by setting the background icon to show Tr il To see the spectrum with no background click the icon to the subtract sei ting Note This does not change the data in the spectrum just the display To change the data you must save the spectrum after subtracting the background PPGT Procedures 81 PRINCETON GAMMA TECH 9 8 Setting Up Calibration Section 6 3 Before a system can be calibrated you must specify the number of channels in the MCA and the full scale energy range This establishes the energy range per channel 1 With the primary spectrum connected to a live device open the Hardware Control ADC2 panel and select the Group Size number of channels and the Conversion Mode In the Bias Preamp tab enable the bias voltage if your system permits Select Setup Auto Calibrate In the Calibration panel select Setup Calibration Setup from its menu bar Click on the radio button for the full scale energy range in keV or 5 Select Setup Manual Calibrate Set Energy Range and click on the desired full energy range for your work If your detector is suitable only for work up to 4 MeV for example do not choose 8192 keV 8 MeV for the full scale range Half of the MCA channels will be wasted and the resolution will suffer A table of keV channel values for different numbers of channels and full scale ranges is on page 42 9 9 System Calibration Using the Auto Calibrate Functions
14. tor Inthe Bias Voltage panel in the PreAmp Bias tab of the Hardware Control dialog box enter the target bias voltage and click Enable if your system supporis bias control Click on the Amplifier tab and set the course gain Try the lowest value first e Click Acquire Adjust the Fine Gain in the Amplifier tab Stop and restart acquisition as you adjust the coarse and fine gain When the two separated peaks appear close to their expected chan nels adjust the ADC settings especially the Lower Level Discriminator value to reduce the low energy noise When the primary spectrum is connected to a live device the first item in the Manual Calibrate menu lets you select the full scale energy range 0 5 Mev Full Scale 1 0 Mev Full Scale 2 0 Full Scale 3 0 Mev Full Scale 4 0 Mev Full Scale 6 0 Mev Full Scale After completing the manual calibration perform the linear Two point Energy Calibration Section 6 3 1 and or the Energy Calibration by ROI Centroids Section 6 3 2 6 3 1 Manual Two Point Energy Calibration The Manual Calibrate Two Point Energy calibration allows you to select two points on a spectrum and assign an energy to each one To run the calibration Expand the spectrum so that you can observe the first peak Bring the pointer to the center of the peak and left click e Enter the correct energy for that position Repeat the procedure for the second point Setup Menu 53
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16. Edit system parameters System Parameters Edit the annotations on the screen Edit Screen Annotations e Edit the nuclide libraries Library 4 1 Copy Spectrum Display Options You can access three Copy Spectrum Display options from the Edit menu Use Copy Spectrum to Clipboard to copy the current spectrum display area including annota tions to the Windows Clipboard The bitmap image is identical to the screen image and can then be pasted into a report or Paint program Use Copy Metafile to Clipboard to copy a bitmap representation of the current spectrum display area to the Windows Clipboard When pasted into a report or into the Paint program the image will show the display area with a white background for printing Use Copy Spectrum to New Memory to make a duplicate of the primary spectrum in a free mem ory buffer You can then modify this copy while leaving the original data unchanged This option is also useful when working with or analyzing data from one sample while collecting data on another You will get better screen and processing response if you make the copied spectrum the primary spectrum and do not display the data being acquired or use the commands in the Spectrum Dis play Control dialog box to turn off the display of the live memory 4 2 Edit System Parameters Choose Edit System Parameters to open the System Configuration dialog box 36 Quantum HPGT PRINCETON GAMIMA TEGH This dialog box contains
17. Energy ntensity For an isotope to be even considered in a particular peak identification routine the USE box to the right of the hal life information must be selected This is the way to create a particular library for use in a specific analysis situation Enable just those nuclides which occur in your routine samples To see only those selected nuclides in the library select the Show where use is True only box at the top of the panel The Nuclide submenu will show only the enabled isotopes To save this library choose File Clone Library from the Nuclear Library Editor file menu Initially all efficiencies are shown as 0 00 When you run calibration the efficiencies determined from the standards are entered for the elemenis in the current library To use these efficiencies to analyze spectra you collect ffom unknowns choose Setup Tool Setup to open the Tool Setup dialog box Select Use Library Efficiencies If Use Library Efficiencies is selected the Lib readout will be green If it is not selected the Lib readout will be red To clear all the efficiencies associated with the selected isotope click Clear Isotope Efficiencies The following information is displayed in the Radiations Data Table of the Nuclear Library Editor dia log box TYPE Defines the primary radiation type for example G gamma SUBTYPE If using x rays specifies the line for example KA1 If using other types of radiation this field may contain desig
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19. The center of a peak is defined as the centroid of the positive lobe of a top hat filter convolved with the background subtracted spectral data The top hat convolution does an excellent job of removing the slowly varying continuum and simultaneously performs a shaping and averaging Generally the value produced as the center will be a more accurate estimate of the line s energy that the centroid The cal culation consists of applying a top hat filter of order M to the region of the spectrum containing the peak M is set equal to the ROI width provided M gt 7 and M lt 101 The peak of an ROI is defined as the highest channel within the ROI The FWHM of an ROI is computed from the background and continuum subtracted spectral data An estimate of the FWHM is computed by starting at the peak of the spectrum and searching to high and low energies until a channel with less than half of the peak counts is found A linear interpolation is then done using this channel and the next channel closest to the peak to determine the FWHM If the FWHM is greater than 12 channels and the spectrum type is not germanium then the data is smoothed using a quadratic smooth of order M M is determined as 0 5 times the initial estimate of the FWHM in the peak plus 1 provided M gt 5 and M lt 25 The same algorithm is then used to recalculate the FWHM from the smoothed data The second moment M2 and the third moment M3 are calculated according the following eq
20. WA GONVENHONS 226244628434 G48 64 Eee Es gl Be ERE GERE 1 1 2 Recommended Hardware Configuration 1 13 installation iyu na zs d s SA m dn dip b di Rab en R E hd m 2 1 3 1 Directory and Path 2 1 4 Hardware Communications Setup Procedure 2 1 4 1 Choosing a Connection Device 3 1 5 Starting the Software 5 1 6 Setting Up the System 6 1 7 Spectrum Display and Memory Control 6 1 7 1 Selecting Spectrum Display and Memory Control Parameters 7 1 7 2 Spectrum Data Readout 8 1 8 User Interface Conventions 8 1 8 1 Data Entry Controls 8 1 8 2 Left Mouse Button 9 1 8 3 Right Mouse Button 9 1 8 4 Detaching the Cursor from the Mouse 10 1 8 5 Keyboard Controls 10 2 MainDisplay 11 2 1 Main Toolbar m0 6 ww sy ee df ap d qid ar EE DD Bl donos 13 2 1 1 Display Control Buttons 15 2 1 2 Adjusting the Display Range 16 21 3 Isotope Markers 18 2 1 4 Manual Peak Identification 19 2 POlTOoDAr sszsgsnrs
21. a second derivative filter with a width dependent on the application type and ADC conversion gain It picks up overlapped peaks particularly good for Nal and other scintillation applications in QCC mode but tends to miss small broad peaks It may pick up more spurious peaks if your spectrum is noisy To eliminate these try setting a lower Stat uncertainty cutoff in the Tools Setup dialog The sensitivity of both filters can be adjusted by setting the Integral and Power parameters which apply to the results of the filter s convolution Their values are shown in the last two columns of the report Use them to adjust the settings in the Tool Setup dialog A peak satisfies the integral requirement if the inte gral of the positive lobe of the filter function is greater than the specified value The power parameter is defined as the integral of the positive lobe of the filter function divided by the width of the lobe This parameter has the greatest effect on finding small wide peaks such as those that might exist in using Nal spectra for wipe analysis In addition certain peaks may be excluded based on the properties of the peaks themselves using the Low Energy and Stat Uncertainty cutoff parameters Section 6 6 1 After the peak search is performed the software displays an interactive peak search result window Move the cursor to one of the rows of peak information and double click the left mouse button to high light the line and advance the spectru
22. eV List Box Within a dialog window a box listing available choices for example the list of all available files in a directory If all the choices will not fit the list box has a vertical scroll bar Live Memory Buffer A spectrum which has been allocated with the NEW function or by loading a setup Data can be acquired into this memory Macro A series of recorded actions in the Microsoft Excel program which can be recalled at will Mac ros can be assigned to special keys called shoricut keys or to longer descriptive names Mass Number The number of nucleons protons and neutrons in the nucleus of an atom Maximize Button The small box containing an Up arrow at the right of the title bar Mouse users can click the Maximize button to enlarge a window to its maximum size Other users can use the Maximize command on the Control menu MDA An acronym for Minimum Detectable Activity Although specific formulations vary the MDA is a measure of the detection limit based on the statistical precision assigned by the operator Menu Bar The horizontal bar containing the names of all the application menus It appears below the title bar Menu A list of items most of which are Windows commands Menu names appear in the menu bar near the top of the window You use a command on a menu by selecting the menu name then choos ing the command MeV The symbol for 1 million electron volts or 10 eV Minimize Button The small box contain
23. incident angle to detector 0 normal Window thicknesses in microns Keys for the materials in the detector definitions Detector dead layer in cm Optimim Bias for this detector Maximum Bias for this detector Reserved for detector find peaks convolution type find peaks convolution avg threshold find peaks convolution integral threshold find peaks bkg width find peaks bkg gap as multiplier of FWHM find peaks ROI width as multiple of FWHM Acceptable range for manual bkg roi chans Spectroscopy type being performed O Gamma 1 Beta 2 Alpha 3 EBEAM 4 XRAY 5 PIXE Flags for analysis 0000 0000 0000 QOCA C no continuum correc A no ambient correc O a FWHM 1 a b E EMatch a EMatch b Lov energy cutoff for peak search Acceptable statistical uncertainty Ka for MDA calculation Kb for MDA calculation Full scale energy of calib in keV Label which replaces Energy on X axis Minimum intensity for a line to be considered in analyses Reserved for tool settings Link to Sample Database Amount of sample in user specified units Uncertainty in amount of sample User specified units for sample quantity Date to report activity as of General reserved space HpGT PGT File Structure 119 PRINCETON GAMMA TEGH Data to describe additional sections of file SpecStart As Integer 1008 First channel in file SpecEnd As Integer 1010 Last Channel in file NZAPs As Integer 1012 Number of ZAP s
24. to Zama FR pecirum LIFE IME delete the last entry or to delete the entire line To carry out the calculation press OK The contents of any spectrum memory can be selected to be part of the equation using a spectrum button for example S 4 for spec trum four The elapsed live time can also be selected by using a live time button for example LT 3 for the live time of spectrum three The following examples illustrate the types of calculations that can be done To copy data from one memory to another e g copy spectrum 3 to spectrum 5 simply enter S 5 S 3 To strip spectrum 2 from spectrum 1 correct for different elapsed live times in the two cases and then store the result in spectrum 3 enter S 3 S 1 S 2 LT 1 L1 2 WPGT Analysis Tools 67 PRINCETON GAMIMA TEGH 7 2 Convolutions The Convolutions tool provides a wide range of r convolution filters for analyzing spectra The results of the filter are displayed in the auxiliary display if the auxiliary screen mode is selected Convolution filters Convolutions form the basis for most peak identification routines nad and many other analytical functions do a ee 207 Convolutions 2nd Derivative The filters are available in a wide range of widths and include the following types gi Top Hai C Peak Finder e Quadratic Smooth e First Derivative Second Derivative e Top Hat e Peak Finder Smooth difference 1st De
25. which shows the results of the latest convolu tion of the primary spectrum A hardware control panel for software control of the MCA hardware The tabs contained in this panel are described in Section 2 3 PPGT Main Display 13 PRINCETON GAMMA TECH Preamp Bias Amplifier ADC ADCZ Stabilizers EstemalContols Presets Shaping Type Coarse Gain Amp Selection Bipolar Gaussian 32 z 2 Internal s External Unipolar Gaussian Amp Input Polarity C Gated Integrator 2 Negative Positive te i Pp z Triangular Fine Gain Agi Reject na Shaping Time Const 1 2068 BL Restoration Rate ise R na usec oo 3 Aak Pileup Reject Output Polarity lil 3 Negative Positive A spectrum information panel containing acquisition and analysis information for the primary spectrum The gray fields report the acquisition date and the Elapsed Real Time Counts The Spec ID field is where you can enter a label of up to 72 characters which is displayed in the Spectrum Display and Mem ory Control dialog box For Quantum products which include quantitative anal ysis fields are provided for the activity reporting date and for the quantity uncertainty and units of sample mass or volume Spec ID MGS1 1049 Eu152 2836755 154 3886677 Eu155 3070863 052191 Elapsed Real Time 561 13 im
26. 0 then this value is a multiplier of the FVVHM for the peak Othervvise this value is expressed in channels Whether values are stored as FVVHM multipliers or channels they are converted to channels for the specific peak for use in actual calculations The Continuum Background correction is calculated as follows First a channel by channel subtraction is done of the background spectrum from the sample spectrum Background Corrected Count 7 el 106 Quantum PP GIT PRINCETON GAMIMA TEGH Here Lc is the elapsed live time of the sample spectrum and Lp is the elapsed live time of the background spectrum The continuum correction is then given by computing the center channel of each continuum back ground region low and high and assigning to this channel value note it may be a fractional channel the average counts in the region For example if the low continuum background region contained three channels as shown below the result would be as shown Channel Counts 123 1845 124 1915 125 1878 Avg 124 1879 3 The continuum correction is then calculated on a channel by channel basis as follovvs p es s 7azS where i is the channel L is the average channel of the low continuum background region H is the average channel of the high continuum background region Lis the average counts in the low continuum background region H is the average counts in the high continuum background region Calculation of the uncertainty
27. 2 00 existing entries Click either New cm or Edit to make the menu and 310 cm Incidence Angle 0 00 den fields accessible Detector Size Optimum Bias 2200 Maximum Bias Voltage Voltage 56 Quantum PP GIT PRINCETON GAMIMA TEGH The detector model supports up to four window materials The material for each layer is selected from a drop down list of available materials In the Detector Window Parameters Material panel enter your best estimate of the thickness of the windows in the appropriate fields All window thicknesses are in units of micrometers 10 meters 10 cm Enter the information corresponding to your detector in the Detector Size panel If you are using a cylindrical detector such as a 3x3 Nal select Cylindrical and enter the diameter and thickness If you are using a detector with a well geometry also enter the well diameter and depth If you are using a detector with a coaxial geometry enter the core diameter and the core depth When determining the core diameter include the dead layer surrounding the core The sample to detector distance should be set for all non well geometries For well geometries set this parameter to zero The detector entrance angle is the angle between the normal to the detector window and the direction to the source For a source direcily in front of the detector this angle is zero For well detectors or in cases where the source covers a very large solid an
28. 6 1 Energy Per Channel 6 2 Automatic Calibration Setup Auto Calibrate automatically adiusts the MCA hardvvare calibrates the system for channel vs energy and for Quantum products vvith only quantitative analysis capabilities calibrates the efficiency of the detector Quantum Note Before using the Auto Calibrate function make sure the items in the Tool Setup dialog box Setup Tool Setup are correct Also check the detector type see Manual Calibration on page 52 to make sure that the type and voltage limits are correct This information will be used by Auto Calibrate to optimize the detector perfor mance and avoid voltages that exceed your detector s safe limits All the Auto Calibrate routines require the use of calibration standards see Creating and Editing a Cal libration Standard on page 44 PG T Setup Menu 43 PRINCETON GAMIMA TEGH 6 2 1 Calibration Setup Select the appropriate Calibration Standard from the menu f there is no standard you must create a new one see Creating and Editing a Calibration Standard on page 44 with the information for your source standard Choose Setup Auto Calibrate The System Auto Calibrate dialog box willopen Choose Setup Cal ibration Setup to open the dialog box shown below User C 1024 2048 C 3072 User Calibration Standard Cs137 C 151 9 Editi New Standard Select the appropriate Full Scale Energy range to set the full s
29. ANS will El21050 2ans E Speaks ans appear first To see other supported EE QCC spectrum example ANS formats choose from the menu at the Files of type field Then dou ble click on the file or click once to File nam DRE Open Open highlight it and press Open o 257 les of type ersion 3 Cancel Open as read only 9 2 Saving a Spectrum The File Save as Spectrum selection opens a dialog box similar to that for loading a spectrum To change the current directory click in the field at the top and choose from the drop down menu You may also click the New Folder button and create a new directory for your work Select the file type Only the PGT default file type ANS has a 1536 byte header the data for each channel and the definition for each ROI All of the information necessary for quantitative analysis is stored in the file header Other supported file types can be selected Enter a name for the file You do not need to include the extension Click Save 5 77 PRINCETON GAMIMA TEGH 9 3 Adjusting the Spectrum Display Range To examine a spectrum more closely it is usually necessary to expand the display range that is to show a smaller portion of the total spectrum In addition to the Horizontal Compress and Expand but tons at the upper right the mouse can be used to select the area of interest Section 2 1 1 Bring the cursor to the
30. Cob 155 5125 Ene Peak 86 5 Std Activity Cuci rgy gt Standard Het Int 86 5168 04 15 31 Calibration Standard Decay Corrected Cuci 49 83 48 02 12E H2 75E H2 Efficiency EFF Curve Delta 123 17 748 3 617 599 a H 44H 886 5 215 Status Elapsed Real Time Elapsed Live Time Peak Counts C3137 Coarse adjust Fine Energy Cal Resolution Cal ficiency Cal Nuc lide Fuihh EuiS5 5125 PPG T Procedures 85 PRINCETON GAMMA TECH 9 10 Creating a Calibration Standard You must have a calibrated standard source to create a calibration standard The information entered in this panel is taken from the certificate provided by the source manufacturer Section 6 2 2 1 Select Setup Auto Calibrate In the dialog box select Setup Calibration Setup To edit an existing standard select that standard from the drop down menu in the center panel For an entirely new standard it does not matter which standard is selected Click Edit New Stan dard This opens the Edit Standard dialog box pe E aeng a dard change any fields as required ID MGS1073 0000000 3 To create a new standard click Nevv This vvill clear all URA MM DD YYYY fields Nuclide Activity 4 Enter all the nuclides in the Mn54 7 standard Click on the coso xi menu button to select from the drop dovvn list Fut5s E 5 Inthe Activity
31. Display and Memory Control Parameters on page 7 for more information about this screen TE Memory Display control opens the Spectrum Display and Memory Control M Display primary spectrum displays only the primary spectrum Spectra are selected enabled in the Spectrum Display and Memory Control dialog box enabled in the Spectrum Display and Memory Control dialog box Tile overlay spectra determines the display mode of multiple spectra In over lay mode left all spectra are displayed in a single window In tiled mode below left each spectrum appears in its own horizontal window See exam Display all selected displays all selected spectra Spectra are selected rara T M N les of both display modes on page 12 The five Auxiliary spectrum data panel buttons below are used to change the dis play area between spectrum display only and spectrum display with an auxiliary spec trum or data panel section m 3 Spectrum infor Auxiliary spec Spectrum con Hardware con mation panel trum display of volution display trol panel for full primary software control spectrum of the MCA Lines mode connects the dots making each spectrum easier to distinguish It only shows the highest point in each column of pixels Bars mode provides a vertical bar for each channel giving the appearance of a solid display This mode makes each spectrum even easier to distinguish but can be slow on older PCs Dots mode plots one dot
32. IP Address An IP address cannot be automatically assigned to your device Ask your network administrator for an address and then type itin the space below linin ar lPaddress autometical of speci an B 6025 IP Address fio f po eo Subnet Mask 255 to fb fb 3738016 10004 OK Apply Cancel The Subnet Mask must match the setting in your computer To check the setting in your computer select the Network icon in the control panel highlightTCP IP and then select Properties After the setting has been sent to the SYS8000 it must be turned off and then back on for the new IP Address setting to be used Finally use the hardware search program to find the SYS8000 using Ethernet instead of RS 232 Introduction PRINCETON GAMIMA TEGH Click on Ethernet in the MCA Devices Auto Configuration dialog box Select ANS Ethernet You must then enter the IP address of the device General Categories of Devices Serial Port RS 485 Plua In Cards GPIB 4881 V Ethernet USB Specific Device Types M ANS Ethernet Include in Search Quantum Ethernet Wadd 10 of of 67 Quantum Ethernet P Add Of of 010 Quantum Ethernet IPad Of Of ofo Quantum Ethernet P Add Of of ofo Once you have checked all of the devices you wish to scan click Update The program will interrogate the ports and locate any MCA devices Each device located will be listed in th
33. PRINCETON GAMMA TECH e Click OK Enter Energy Select Second Point with Mouse 3405 Ea MM A linear energy vs channel calibration is then computed from the designated points This is a quick approach to getting a reasonable calibration You can use it with a saved spectrum if you are certain your system has not changed However if your work requires higher accuracy calibrate using the Energy by ROI Centroids method 6 3 2 Manual Energy Calibration by ROI Centroids Energy by ROI Centroids is a multi point manual calibration procedure The system displays a list of all ROIs for a spectrum including their centroids You may assign energies for as many ROIs as you want for use in either a linear or quadratic calibration To run the calibration Choose Setup Manual Calibrate Energy by ROI Centroids to open the Manual Multi Point Calibration dialog box below Select peaks with known energies by left clicking to select them from the list You can also use the Next or Previous buttons to move through the list A full height marker appears on the main spectrum display indicating the peak selected For a better view of the spectrum during peak selection move the dialog box out of the way or minimize it Enter the energy of the selected line in the Energy box After you have entered the energies for all the selected ROls select either a Linear two point or Quadratic multi point calibration 54 Quantum PGT PRI
34. QCC spectra than in linear spectra The Power parameter will have little effect except in linear spectra with wide weak peaks The meaning of the Sensitivity parameters is very different for the Overlapped and Low Pk To Bkg modes In Low Pk to Bkg mode the Integral parameter will typically be propor tional to the net peak integral In Overlapped mode it is a measurement of the smoothed magnitude of the second derivative and reflects places where there are sharp changes in the spectrum shape The meaning of the Limits parameters is independent of the search mode because the lim its always apply to the peaks themselves The Uncertainty cutoff is useful under any condi tions to screen out peaks that are indistinguishable from noise li is generally easier to set the parameters slightly too sensitive and then erase unwanted ROls than to try to get exactly the right setting Some of the measurements such as Power and Uncertainty may be affected by the reso lution of your ADC As you increase the number of channels you increase the width and decrease the height of the peaks If you change the conversion gain of your system you may need to adjust your search parameters 64 Quantum PRINCETON GAMIMA TEGH You can obtain greater control over the peak detection and matching process by combining the sensi tivity and limits For example the Overlapped Peaks search mode will often give large numbers of apparently false peaks in
35. adjacent lines by less than 4 times its FWHM or its stored FWHM is greater than 1 5 times its calculated FWHM at its center energy 71 72 Quantum PRINCETON GAMMA TEGH 7 8 Rapid Scan Quantitative Analysis Systems Only File Repor Type Activities reported as of Measurement Date NUCLIDES FOUND WITH HIGH PROBABILITY 8 592 Y B Corr Coeff 0 955 Activity 135742 1215 9 RAD CENTER GROSS NET ROI Activity INT cnts cnts ASSIGNMENT 40 4 123 16 209814 458 92692 666 Eu1548 123 100607 248 01 18761 591 92 5842 723 53 15534 4 8 137 14907 9 Oo 9 757 03 4753 1 3 g 4 8 76 3613 125 13132 9 2413 90 6266 z 5400 102 8709 116 12495 28 94 166 Fuls4 247 112 Fuls4 591 153 Fuls4 722 111 Fuls4 756 122 Fuls4 873 103 Fuls4 996 130 Eu 154681004 131 Eu13 5481274 34 Eu 15481506 142292 109261 123147 106426 124950 152533 144004 163979 2976186 673 49 8144 996 61 6796 1005 10 10423 1274 90 13444 1596 91 770 HE HE HE HE HE HE HE O O O Un un 20 20 Ma O 20 DO qo pi 1 9 B 3 9 ait 3 B E NUCLIDES REJECTED MDA 152 3046 2 10 15 lines found corr The Analyze Rapid Scan routine simultaneously calculates quantitative information along with the qualitative information of the Peak Identify routine The activities it calculates will only be correct if the system has been properly calibrated f
36. all lines for the specified isotope which lie inside the ROI The total intensity is then used to calculate the activity The report simply lists the calculated results for each nuclide that had been identified in the spectrum i Analysis Report by Nuclide Ea File Report Type Activities reported as of Heazurement Date HUCLIDES ANALYZED 4 680 Y H Activity 0 231 1 08E 02 uli CENTER NET ROI keY cnts ASSIGNHENT 86 56 z not 277 1558 86 5 105 34 5 261 257 Eul55 105 3 13 542 Y H Activity 4 229 4 40 02 uli 13 542 EC Activity 4 229 4 40 02 uli CENTER ROI keY ASSIGNHENT 121 64 E Eu15286 121 8 244 79 E EulS2 244 7 344 37 E EulS2 344 3 411 24 2 Eu1528 411 1 This approach works well for many Nal applications and alpha spectra It is also useful for many other applications where specific lines and nuclides are being analyzed 7 10 1 Saving Analysis Data with Spectrum A summary of the analysis data can be saved with the spectrum Choose Spectrum info for the display mode The white fields let you enter a spectrum ID the activity Quantity and Units Save the spectrum This information is now included in the spectrum header and can be viewed with View Setups PPGT Help Menu 75 PRINCETON GAMMA TECH 8 Help Menu The first level of on line help for Quantum software is Tool Tips Bring the screen cur impp sor over any toolbar icon to see the name of that tool For m
37. analysis by saving a set of ROIs created in one spectrum and using them in another series of spectra collected under the same conditions Choose File Merge ROIs to perform the same actions as the Load ROIs command except that any existing ROIs are retained The new ROIs are added to the already existing ROIs Choose File Save as ROIs to save the ROIs from a specific spectrum The ROI file contains the energy window name and nuclide association 3 1 Print Options Choose File Print Spectrum to print a full page spectrum display with minimal additional information The layout and energy range is identical to the current layout of the screen display Choose File Print Primary and ROIs to print only the primary spectrum as displayed and its associ ated ROI information You can configure your printer to print these options in either portrait or landscape mode 3 0 1 Report Setup Use the commands contained in the File Report Setup dialog box to customize the report headings You can include the current date as the third line of the heading and print ROIs as wide lines By default data is printed in full color output but you can select Send to Printer as B amp W to print out the results in black and white Setup Report Formats Print Spectrum The Print Spectrum dialog box includes a olni list of report header options Check each box DS 2 to the left of each option you vvant to appear nnunuuuuuu in the printed rep
38. analytical processes is for the most part transparent to the user The analyt ical software can automatically set ROIs as needed However the system allows you to set ROIs man ually and to edit ROIs set by the software See Creating Editing and Deleting ROIs on page 78 for additional information on setting and editing ROIs for manual analysis ROls are handled quite differently from those in a classical MCA There are two main types of ROIs e Foreground Unknown Identified Background Because of the major differences in the way background ROls are used and processed they are counted and processed separately PPGT Main Display 21 The ROI field provides information on the current ROI To make an ROI current left click it The field background color and the ROI color in the spectrum indicate the type and status of the ROI In the PGT default colors e Red indicates unknown foreground ROIs e Green indicates identified foreground ROIs e Magenta indicates background ROIs Some additional foreground ROI capabilities exist The isotope ID field shows which nuclide if any is associated with the ROI The association can happen automatically through one of the identification procedures or it can be set manually by holding down the ALT key while clicking on the center of the ROI and selecting a nuclide from the line list pop up The ID for foreground ROIs can be set by the user or can be filled in automatically by an analysis procedu
39. associated with the is quite complex to calculate precisely The uncer tainty in S is approximately 5 Jn where n is the number of channels in each continuum back ground region When PGT software automatically sets background regions the low and high continuum regions are the same width and are symmetric about the peak In this special case we can simplify the calculation as follows Continuum Counts K NR z s X 2N i L i H where Np is the number of channels in the ROI Ny is the number of channels in each continuum background region and the two sums are the total counis in each of the continuum back ground regions Here the estimate of the uncertainty in K is much easier to calculate being given by N 2 E Here attention must be called to the potentially large multiplier Np 2N Since most software uses only a single channel for computing the continuum background on each side of the peak large uncertainties can be introduced in the result when a peak sits on a large continuum back ground PRINCETON GAMIMA TEGH PPGT Analysis Algorithms 107 The net counts for the ROI are then given simply by N C B K The activity is not computed by ROlupdate t is computed by the specific analytical routine being used The centroid is computed from the background and continuum corrected spectral data according to the formula SSE Centroid 7 where is the energy of the channel
40. close the dialog box 5 3 ROI Toolbar Display Choose View ROI Toolbar to display the ROI toolbar in the main data display window Note that the ROI toolbar must be open in order to show ROIs and ROI labels on the displayed spectrum or spectra If the toolbar is not displayed you can still view ROI information in the status bar When you move the pointer within an ROL in the primary spectrum the ROI label its integral and centroid are displayed Quantum PGT PRINCETON GAMMA TECH 6 Setup Menu The Setup menu contains a series of commands used to access the various calibration and system setup functions Auto Calibrate Manual Calibrate Detector Parameters Clear Calibrations Tool Setup Select Screen Report Font Select Display Colors Two Point Energy Energy by AO Centroids Resolution Calibration 6 1 About System Calibration Table 6 1 shows the energy per channel for different numbers of channels and full scale energy ranges The number of channels is set in the Group Size panel in the ADC2 tab of the Hardware Control panel see ADC Controls on page 24 You can set the energy range using either the Auto Calibrate or the Manual Calibrate functions Number of keV per Channel for Selected Full Scale Energy Ranges o lo5Mev 10MevV 120MevV 140MeV 8 0 MevV 1 0 MeV 2 0 MeV 4 0 MeV 6 0 MeV 1024 keV 2048 keV 4096 keV 8192 keV 10 0 keV ch 20 0 keV ch 40 0 keV ch 80 0 keV ch 1600 0 keV ch Table
41. for each data channel classic MCA mode Use this mode if you want to see every data point when all of the channels are dis played 16 Quantum PP GIT m PRINCETON GAMIMA TEGH Quantum Note The display mode you choose dots lines or bars will affect the appearance of your data in ways you may not realize In dots mode a point is drawn on the screen for every channel If you are viewing an 8192 channel spectrum then 8192 dots will be drawn Since there are between 500 and 800 pixels across the spectral image depending on your video resolution there may be several points plotted in every column of pixels You see a band of data across the screen In lines and bars modes multiple channels may be mapped onto a single column of pixels The pixel plotted is the highest pixel within the column This gives your data an appearance of reduced statistical noise If you were to compare a raw spectrum to a smoothed one in one of these modes the smoothed one would appear to fall below the raw data when viewed over the maxi mum size As you zoom in to smaller sections of the spectrum you would see that the smoothed data does actually pass through the center of the statistical noise Be aware of how the data is displayed so you will not be misled Grid horizontal vertical both none leis you choose whether to include a grid on the screen display to make peak positions and heighis easier to esti mate Vertical grids divide the screen i
42. lines and their relative heights When you change the isotope selection the current markers will be erased and the markers for the new isotope will appear The easiest way to move to adjacent isotopes in the list is to click in the Isotope drop down list to select it Then press the keyboard 7 or key to move to the next entry in the list or press or to move to the previous isotope You can move through the entire list this way You can also type in the new isotope symbol and press the key board TAB to show the new set of markers To examine a particular line more closely click on the Line List for Selected Isotope button to the right of the Isotope drop down list to open a pop up menu displaying all the enabled lines for the selected isotope right If you left click a line in the list a blue vertical line at that energy will appear on the display If you expand the spectrum to view just that peak and its sur roundings you can observe the shape of the peak and how well it is centered on the line Energy Intensity Use the T and J keys to move through the list 2 2 ROI Toolbar The Region of Interest ROI toolbar is located at the bottom of the main data display screen just above the status bar Peak Background ROI ROI Markers Edit ROls F o arzumuza 10 1520 121 8 Netintegrat 96 057 7055 RR KEN x q K Current ROI Estado ID Peak htegral Peak FWHM Clear ROIs The use of ROIs in most
43. of atoms of a radioactive nuclide which decay in unit time in the equation N N e 9 where N is the initial number of atoms present and N is the num ber of atoms present after some time t Disintegration Nuclear A spontaneous nuclear transformation radioactivity characterized by the emission of energy and or mass from the nucleus When numbers of nuclei are involved the process is characterized by a definite hal life Display Controls A data panel that allows user specified screen display options to be accessed and selected Double Click To rapidly press and release a mouse button twice without moving the mouse Double clicking carries out an action such as opening an icon 127 128 Quantum PP GIT PRINCETON GAMIMA TEGH Efficiency Counter or Detector A ratio of the number of counis recorded in a photo peak relative to the number of photons emitted Electron Volt eV A unit of energy equivalent to the amount of energy gained by an electron in pass ing through a potential difference of 1 volt Larger multiple units of the electron volt are frequently used viz keV for thousand or kilo electron volts MeV for million electron volts and BeV for billion electron volts 1 eV 1 6 x 1072 erg Electron Negatively charged particle which is a constituent of every neutral atom Unit of negative electricity equal to 4 8 x 1079 electrostatic units or 1 6 x 1079 coulomb its mass is 0 000549 atomic mass units Eleme
44. on these primitives a variety of com mon operations are available for users who do not want to be forced to write their own software The looping constructs deserve special mention since their use is more complex than the simple directives provided by the other commands The Loops command should be placed early in the file immedi ately after Connect is a good place to allow the user to select the number of iterations before the loop begins Any number of loops can be used and they can be nested up to a depth of 10 The AutoSaveSpc command should only be used inside a loop From the QScript interface the first four characters of the text in the text box to the right of the AutoSave button will be used as the prefix for the stored spectra When running scripts using QScript you should be certain to copy rename or save the spectra saved as part of the script or change the script itself because otherwise the saved spectra will be overwritten the next time that script file is run If you forget a step while making a script file you can enter the com mand at a later point and then cut and paste it to the correct line Or you can just type it in keeping in mind that the commands are case sensitive You may also find it easier to use different values when creating the script running a short analysis time like LivePreset 10 for example and then editing the values later once you have verified that the script performs the sequence you
45. search list Since an isotope can have more than one line associ ated with it we calculate the activity of each isotope as the weighted average activity of the lines found for the isotope The weighting function w is the ratio of the measured activity to its uncer tainty Weight W A o LWA Isotopic Activity A Fw W 1 1 Uncertainty o 5 A 5 2 Analyze ROI Directed In the ROI directed approach the user assigns a Nuclide to each ROI in the spectrum This can be done through the Peak Identify or Analyze Rapid Scan functions by manually setting the Nuclide field on the ROI panel or a combination of both An ROI can cover a single line a multiplet of lines or sev eral unresolved lines the four Ba133 lines from 286 keV to 384 keV which form a large glob on Nal systems To determine the theoretical intensity of the ROI the system searches the library for all lines for the specified isotope which lie inside the ROI The total intensity is then used to calculate the activ ity To use the ROI Directed approach you need to do the following BEFORE selecting the function 1 Set an ROI over each peak in the spectrum you want to be included in the analysis You can do this manually or by using Peak Finder You can use Peak Finder and edit its results 2 Associate a nuclide with each ROI Either use Peak Identify Rapid Scan or manually set the associated nuclide in the ROI control panel 3 Make sure the appropriate l
46. still be red Use ALT left mouse to see what possible nuclide s have lines in that region It may be a nuclide line that was disabled in the Library or an unexpected nuclide that was not selected for Section 4 4 inclusion Use box not checked page 37 In the spectrum display all identified ROIs are now green The ROI field will also be green it includes the ROI number its label and its ID 90 Quantum PP GIT PRINCETON GAMIMA TEGH 9 15 Quantitative Analysis Rapid Scan Quantitative analysis is available only with the QuantumGold This requires that you have used cali brated source standards to create calibration standards and have run the Efficiency Cal procedure in Setup Auto Calibrate 1 Section 7 8 page 72 2 Make sure your system is fully calibrated and that the Tool Setup entries are correct Collect the spectrum Select Analysis Tools Rapid Scan The software does a Peak Search followed by Peak Identify with quantitative resulis included Check the spectrum display for unidentified ROIs or missed peaks Identify them if needed and delete any peaks that are not true nuclide peaks Re run Rapid Scan You may find that it is advisable to do the separate Peak Search and Peak Identify routines on the first soectrum to optimize their results Save the report or print it by selecting File Save Report as Text File or File Print Report from the report window menu bar 9 16 Quantitative Analysis with Deconvolu
47. sy uolls nboe 10 SWI OU JOS Buus sy sy 99 QScript 9ABS InISS ns MO aves 1 0 U AES 4 40 odes HulAes JO weuyzed pijea yed 1SII Ul 10U d 1SIS yoda eue jou adAjsisAyeue d Wodsy sisAjeue Ajuap ye d y uap yeed Buns Woda ye d au DPUIJYCOd sem yde aweu lli pue Woda jdods ISNIN od IsiS jeuy 49 au o 1 e yewo Buijs ul IOH 40 n EA PISA IOH 40 YAN OH 18 u lolz 1049949 IOH 0 peubisse AHATOV IOH o poubisse JUdWaINSeewW 10111 05 011500 1 10 UOIISOd PIOJJUSD JO UONISOA IOH UI S JUNOD JON IOH UI SJUNOD UINNUNUOS IOH ul sjunoo punoJbyoeg IOH UI SJUNoD 5850 01 14 VAIN AAALAC AAL ALLOV AV 431 LAN LNOOs ODA MOPUIM WINUBND OU SZILUIXEIA Bus se oziwixeN MOPUIM UINJURND OU 9ZILUIUIA Bus se ziuluiy T PRINCETON GAMMA TECH P p s nb au Aq MO 5 om ou poubisse s s dwoo Bulls unas aU peisenbas anjeA MO SI IOH 3y YoIUM O pilonN 20 20 0 1 45 uo d
48. the matching lines in the spectrum and the lines of the isotope The intensity of each measured line corrected for detector efficiency is correlated against the theoretical intensities from the database A line is assigned to a particular isotope if it is most highly correlated to that isotope and the abso lute value of the correlation coefficient is greater than 0 4 The Rapid Scan approach depends on there being exactly one line in the library for a given isotope for each peak in the spectrum If several lines from the isotope form an unresolved multiple or if there are overlapping lines from different isotopes this approach will not yield good results Analysis Tools 73 PRINCETON GAMMA TECH A detailed description of the calculations performed in all PGT analytical routines is provided in Appendix A 7 9 Analyze with Deconvolution Analysis Tools Analyze with Deconvolution is the best procedure for spectra with unresolved mul tiplets or overlapped lines from different isotopes The ROIs are first deconvoluted into Gaussian peaks which then replace the original ROls Each new ROI is more readily matched to the lines in the library The report generated has the same format as that from Analyze Rapid Scan After the analysis is complete a Deconvolution display window pops up to show the same portion of the spectrum as the main display area This shows the Gaussian peaks as different colored solids the orig inal spe
49. the output to the nearest possible value Finally some devices have one or more general purpose input or output bits Output bits can be checked on and off using the external out bits check boxes Input bits show up as green lights when driven true or gray when false For many of these controls you will need to consult your hardware manual for more details on the cor rect values to enter or to find out which connectors provide the necessary signals 2 3 6 Presets PreAmp Bias Stabilizers Controls Presets Count Preset Type Real Time secs Live Time secs Integral Integral of all ROIs ICR Counts fo fi 80 fo C Integral of Selected ROI C SCA Counts Peak ents Gross ROI Statistics External Counts ni Net ROI Statistics C Off Enable Presets The system supports three simple presets real time live time and peak and one general purpose count preset Not all hardware devices support all of these presets and some presets are more accu rate than others in certain devices Only the modes supported by the particular hardware device will be displayed on the presets panel Preset values are entered into the appropriate boxes In order for pre sets to take effect they must be enabled by selecting the Enable Presets check box Presets are loaded into the hardware at the start of the next data acquisition Therefore to change a preset while running you must stop acquisition change the pr
50. this option the Load Spectrum dialog box will open Load Spectrum E P Warming Loading a spectrum inta liwe memor will replace all device parameters and calibrations Proceed Click Yes to continue Click No to cancel the operation Note Some MCA device memories cannot be overwritten The existing calibrations hardware parameters and setup associated with the primary spectrum are unchanged allowing you to load and analyze a series of spectra using the same set of device calibra tions Make sure this is what you want to do since the parameters associated with the spectrum file will be ignored even if they are different If library efficiencies were used in analyzing the spectrum to be loaded there will be one of two warn ings The associated library exists but efficiencies may have changed since acquisition OR The associated library was not found All efficiencies will be calculated from the Calibration Equation If the second warning displays the Use Library Efficiencies in the Tool Setup will be automatically switched off 3 3 Import User Import User is a new feature that allows you to convert spectrum files in other formats into ANS format for use with Quantum software This option is only available if the stand alone application file QtmCon vert exe is in the same directory as Quantum PPGT File Menu 31 PRINCETON GAMMA TECH Choose File Import User to open the Qtm Spectrum file import u
51. to set the card up with IRQ and DMA channels enabled When the stage is reached where the National Instruments software recognizes the controller card and the PCA M units attached to it the Quantum software will be able to control the PCA M It is recommended that you run the controller card with IRQ enabled Otherwise the response time of the unit is considerably slower Note that some National Instruments controller cards such as GPIB do not run under Windows NT or Windows 2000 1 4 1 4 Ethernet Quantum correctly supports simultaneous acquisition from up to four Ethernet acquisition units Newer MCA products such as the MCA8000 and System 8000 use Ethernet 10 100 base T and RS 232 To use the ethernet connection first check for the presence of NETSETUP EXE in the Quantum folder Establish communications with the SYS8000 using an RS 232 communications cable Use the HVVSsuper exe hardware search program set for 19200 baud and then test run Quantum to verify communications with the SYS8000 Quit all Quantum related software Then run NETSETUP EXE In the panel click on the IP Address tab You will see the system device ID displayed in the lower left corner of the TCP IP Ethernet Setup dialog box This verifies that the program is communicating with the System 8000 Enter the IP Address The address used to test the unit at the factory is 10 0 0 67 and you may continue to use this address m TCP IP Ethernet Setup Ioj x
52. try to determine what isotopes these peaks represent PGT software uses a multi pass correlation technique to determine what isotope each line is most likely to represent Only those isotopes which are enabled in the library being used will be considered For these isotopes only the lines marked as enabled will be considered Pass 1 Energy Matching In pass 1 the center energy of each peak in the spectrum is compared to the energy of each line in the library The number of lines in the library which match the peak within Ewindow is recorded in Hits Similarly a record is kept of the number of lines for each isotope which have matches in the spectrum Pass 2 Correlation Calculation In pass 2 a cross correlation coefficient is computed for all isotopes which have one or more lines which match the peaks of the spectrum The cross correlation coefficient is defined as 2 Eang 2727 Here A is zero unless the energy associated with database line i is within Ewindow of the energy associated with the peak j Y is the theoretical intensity of the spectral line from the database S is the net counts of the ROI and F is the efficiency of the detection system for the energy in question This cross correlation coefficient is extremely sensitive to the match in theoretical and measured intensities of the lines One should generally expect values of 0 75 or greater for the correlation coefficient when peak to background ratios are reasonable
53. used and the thresholds for the TXint and TXavg parameters for accepting a peak The specified convolution is then applied to the background subtracted spectrum The result is scanned starting at channel zero for positive values When a positive value is encountered the beginning of a region is marked The integral and average of the positive lobe is computed until a negative value is encountered These parameters are then compared against the acceptance levels specified If BOTH values pass then a new ROI is created The following parameters in the QROI structure are computed StrEnergy EndEnergy GrossCounts Center and Peak The ROI type is set to 1 and the ID is set to UNK xxxxx where xxxxx is the energy of the center of the peak PGT MCA emulation packages allow the user to adjust the sensitivity of the peak finding algorithm by changing the values of TXint and TXavg The overlapped mode in the peak finder setup utilizes the second derivative filter In the low peak to background mode one of the two top filters is used The sys tem decides on the simple top hat or variable top hat depending on how much the resolution of the peaks varies across the spectrum In most cases the Peak Finder is immediately followed by ROlupdate to fill out the information in the ROI PPGT Analysis Algorithms 109 PRINCETON GAMMA TECH A 4 Peak Identification Once a spectrum has ROls set either by Peak Finder or by the user the next step is often to
54. will become the full scale value and autoscaling will be turned off The auxiliary spectrum display has its own Expand Vertically and Contract Vertically buttons This display is always in linear mode An enhanced live mode maintains the spectrum at 96 of the display s full height by allowing the full scale value to be changed in non power of two incremenis After the first few seconds the spectrum display remains nearly constant as the counting statistics improve 2 1 3 Isotope Markers Quantum software provides both automatic and manual peak identification Both functions use the Nuclide Library to match the line energy with a nuclide See Nuclear Library Editor on page 37 for instructions on editing this library Manual identification is done through the nuclide display controls in the main toolbar while automatic identification uses the Analysis Tools options see Analysis Tools on page 66 and labels the identified peaks using the ROI toolbar markers see ROI Markers on page 21 Click Library left to open the Select Library dialog box The menu lists all the available libraries Left click to EE ORE NES en select the appropriate library and click OK To close the unu dialog box vvithout making any changes click Cancel GAMMALIB MDB The name of the selected library will be displayed on the primary spectrum information line If it is dis played in green the Tool Setup has Use Library Effi
55. 0 2 Stabiizess Extemal Controis Preses 1 Zero Stabilizer j Gain Stabilizer Mode Zero ROI Mode l Gain ROI ott Start End C Off Start End Areenan TE ps0 p97 AARAA ampie Time 10649 10684 ROI Centering l Number po ROI Centering Number Po Drift correction Drift correction poooz Reset Reset Off __PreAmp Bias abc ADCZ st bilizers L Controls r Zero Stabilizer Gain Stabilizer Mode Zero ROI Mode ROI nif Start End Off Start End le Ti Sample Ti Edge Eenterma bu h l m Edge Centenng m Auto Auto C HO Centering Number 4 RUI Centering Number Drift correction a Drift correction a poz Reset Foon Your ADC may have the gain and or the zero stabilizer available Each one allows you to select a mode if available time constant if available and ROI In addition to switching the stabilizer off the two available modes are edge centering which computes the drift in the center of the ROI by changes in the heights of the channels at the edges of the ROI and ROI centering which uses the complete ROI centroid to determine a drift in the ROTs position On a few devices the gain stabilizer can operate over multiple ranges to accommodate different types of detectors Simply enter the desired range in percent and the nearest value will be selected Fo
56. 0652 DetSourceDist As Single 0656 DetIncAngle As Single 0660 DetWinThick 0 To 3 As Single 106641 DetMt1 0 To 3 MaterialStruct 0680 DetDeadLayer As Single 0816 DetBiasOptimum As Single 0820 DetBiasMax As Single 108241 RESV828 0 To 3 As Byte 0828 Tool Settings PKmode As Integer 0832 PKpwr As Integer 0834 PKintg As Integer 0836 BKGwidth As Integer 0838 BKGspread As Single 10840 ROlvidth As Single 108441 BKGROIRange As Integer 1069461 APPType As Integer 0850 AnalysisCtrl As Integer 0852 EMatchMode As Integer 0854 EwinA As Single 0856 EwinB As Single 0860 PKminengy As Single 10864 As Single 0868 MDA_Ka As Single 0872 MDA_Kb As Single 0876 EnFullScale As Integer 10880 XaxisLabel 0 To 11 As Byte 0882 padl As Integer lineminintensity As Single 0894 RESVOS98 0 To 5 As Byte MKRB 0898 Sample information SampleKey As Long 0904 SampQuantity As Single 0908 SampQuantUnc As Single T09121 SampUnits 0 To 3 As Byte 0916 SampActivDate As Double 109201 Reserved space RESVO928 0 To 79 As Byte 0928 HPG T PRINCETON GAMMA TEGH Detector Type 0 Nal 1 HPGeN 2 HPGeP 3 SiLi 4 GasF 5 510 Detector shape 0 Cyl 1 Well 2 Coax 4 Detector Name Thickness of detector Diameter of detector Diameter of well Depth of well source to detector distance
57. A TECH INSTRUMENTS REPRESENTATIVE HAS BEEN ADVISED OF THE POSSIBIL ITY OF SUCH DAMAGES PRINCETON GAMMA TECH INSTRUMENTS WILL NOT BE LIABLE FOR ANY SUCH CLAIM BY ANY OTHER PARTY This limited warranty gives you specific legal rights Some states provide other rights and states do not allow excluding or limiting implied warranties or limiting liability for incidental or consequential damages As a result the above limitations and or exclusions may not apply to you Furthermore some jurisdic tions have statutory consumer provisions which may supersede this section of the Agreement GENERAL If any provision of this Agreement shall be unlawful void or for any reason unenforceable then that pro vision shall be deemed severable from this Agreement and shall not affect the validity and enforceability of the remaining provisions of this Agreement This Agreement is governed by the laws of the State of New Jersey US GOVERNMENT RESTRICTED RIGHTS The Software and accompanying materials are provided with Restricted Rights Use duplication or dis closure by the Government is subject to restrictions as set forth in subparagraph b 3 ii of The Rights in Technical Data and Computer Software clause at 252 227 7013 Contractor manufacturer is Princeton Gamma Tech Instruments 1026 Route 518 Rocky Hill NJ 08553 USA VFapiGT Table of Contents PRINCETON GAMMA TECH Table of Contents 1 Introduction 1
58. AMMA TECH lonization Path Track The trail of ion pairs produced by an ionizing radiation in its passage through matter lonization Total The total electric charge of one sign on the ions produced by radiation in the pro cess of losing all of its kinetic energy For a given gas the total ionization is closely proportional to the initial ionization and is nearly independent of the nature of the ionizing radiation It is frequently used as a measure of radiation energy lonization The process by which a neutral atom or molecule acquires a net positive or negative charge Isobar One of two or more different nuclides having the same mass number but differing in atomic number Isomer One of several nuclides having the same number of neutrons and protons but capable of existing for a measurable time in different quantum states with different energies and radioactive properties Commonly the isomer of higher energy decays to one with lower energy by the process of isomeric transition Isotope Stable A non radioactive isotope of an element Isotope One of several nuclides having the same number of protons in their nuclei and hence having the same atomic number but differing in the number of neutrons and therefore in the mass number Almost identical chemical properties exist between isotopes of a particular element The use of this term as a synonym for nuclide is to be discouraged keV The symbol for 1000 electron volts or 10
59. ARE ONLY FOR PURPOSES DIRECTLY RELATED TO THE USE OR SUPPORT OF PGT HARDWARE AND SOFTWARE SOFTWARE LICENSE AGREEMENT THIS AGREEMENT IS A LEGAL CONTRACT BETWEEN YOU THE END USER AND PRINCETON GAMMA TECH GOVERNING YOUR USE OF THE SOFTWARE THIS AGREEMENT SHALL ALSO BE BINDING ON ANY SUBSEQUENT AUTHORIZED LICENSEE IF YOU DO NOT WISH TO AGREE TO THE TERMS OF THIS AGREEMENT PROMPTLY RETURN THE COMPLETE SOFTWARE PRO GRAM PACKAGE WITH THE CD PACKAGE S TO YOUR POINT OF PURCHASE YOU WILL RECEIVE A FULL REFUND PROVIDED YOU RETURN THE FULL SOFTWARE PACKAGE IF YOU HAVE ANY QUESTIONS CONCERNING THIS AGREEMENT CONTACT PRINCETON GAMMA TECH INSTRUMENTS ATTN SALES 1026 ROUTE 518 ROCKY HILL NJ 08553 609 924 7310 LICENSE Princeton Gamma Tech Instruments grants you the right to use one copy of the Software on a single user computer or on a single terminal or workstation of a multi user computer or local area network Each workstation or terminal on a multi user computer or a local area network must be separately licensed by Princeton Gamma Tech Instruments You may not sublicense rent or lease the Software but you may transfer the Software and accompany ing materials to another user if there is no possibility that the software will be used on more than one computer at a time The new recipient of the Software and accompanying materials accepts this Agree ment and is licensed under the terms of this Agreement upon initially using the Softwa
60. Channel Data displays the data in the primary spectrum as a tabular output of eight channels per line The onscreen report is truncated because of length but all the data appear when the report is printed or saved to a file 7 4 ROI Data The ROI Summary Report is a listing of any defined regions of interest ES ROI Summary Report EI File ID ASSOCIATED CENTER NUCLIDE Eul526 Eul55 Eul526 155 UNK 6 Eul55 Eu1556 105 Co57 122 1 Eu1546 123 UNK e 188 Eu1526 244 Eul546 247 UNK 296 Eu1526 344 UNK 367 UNK 371 Eul526 411 1520 444 UNK 582 CU A 1 2 3 4 5 6 7 8 9 He iF mmm br br br H Hr he H H H h rr i hH h 111 mm o a a a o a 1 GGeuQQuQQQQQQQQQQQQ ORR AD O CD AD NIM ha The list includes ROI number e ROI ID e Associated nuclide e Centroid energy e Gross Counts and error e Net Counts and error e FWHM Move the cursor on top of one of the rows of the ROI report and double click the left mouse button to place a marker at that peak in the spectrum The report can be saved to a text file or sent to the printer with the selections from the File menu of this panel Select File Exit to close the panel 7 5 ROI Details Analysis Tools ROI Details displays a list of information calculated by the system for each ROI in the spectrum The following information is included Quantum Parameter Description Gold Name assigned to ROI 12 characters su
61. GT software values which have an uncertainty associated with them are stored in tRES structures which consist of a variable of type double for value and another variable of type double for uncertainty Calculations with tRES structures are done with a series of subroutines which calculate a new value and its uncertainty tCalcAB R A B 2 2 2 o B oF A o tCalcABC R A B C 2 DZ 2 20 2 wed 2 D2 xe o B C o A CCO tCalcAoverB R A B 2 52 Bro AO tCalcABoverC R A B C 1 gB o A o A B C oz tCalcAoverBC R A B C A A 2 2 2 2 Or B2C 04 B ir Oc tCalcAplusB R A B O 0 0 tCalcAminusB R A B O 0 0 104 Quantum PP GIT PRINCETON GAMIMA TEGH Though no explicit routine is defined for the general case remember that the general form of propaga tion of errors for Z which is a function of two parameters X and Y defined by Z f x 9 y Where X has an error o associated with it and Y has an error o associated with it then the error associated with Z is given by of of 08 Ox dy Unless specifically noted otherwise calculations done using variables with associated uncertainties follow the above calculational process 2 2 2 0 _ o A 2 ROI Data Calculations When a peak in a spectrum is analyzed we create a Region Of Interest ROI over the peak In PGT software the start and end of this region i
62. Inpu F amp Other Differential Set 2000 aj Point E Leakage Current 7 Actual 3000 Pos The PreAmp and Bias controls are contained in a single panel These controls allow the selection of an internal or external preamp and allow the user to adjust the bias voltage set point and to enable or disable the bias supply The polarity of the bias supply if known will be shown and if the device sup ports an actual bias readout distinct from the set point this will be shown If a device supports any of the alarms select Enable to show the status of the alarm green for OK red for fault condition in the Status column The alarms are not otherwise interpreted by the software If the hardware supports an automatic shutdown capability select Auto Shutdown to instruct the hardware to shut down under the specified conditions f you wish to use this feature please verify with your hardware vendor that the auto shutdown capability of their hardware is compatible with your detector system 2 3 2 Amplifier Controls Preamp Bias Amplifier 0 2 ExtemalContols Presets Shaping Type Coarse Gain Amp Selection r m 32 Internal C External Bipolar Gausstar so J Unipolar Gaussian Amp Input Polarity C Gated Integrator Negative C Positive Pileup Reject Output Un Triangular Fine Gan Shaping Time Const BL Restoration Rat
63. Is after they have been set 22 Quantum PP GIT PRINCETON GAMMA TECH Each button has two symbols on it that indicate the effects it has on the right and left boundaries of the ROI to which it is applied e The arrow symbol indicates that the boundary of the ROI will be moved one channel in the direction of the arrow For example clicking the bottom right button would move both boundaries of the ROI one channel to the right e The vertical bar indicates that the corresponding boundary will not be moved For example clicking the second button of the top row would move the left boundary of the selected ROI one channel to the right while leaving the right boundary unchanged 2 3 Hardware Control Panels The Hardware Control panel is located below the spectrum display area In order to view the panel you must select and open it using the Auxiliary Display button on the main menu The contents of the panel depend on the type of MCA hardware you have The controls correspond to the current primary spectrum and change when the primary spectrum is changed When an active live piece of hardware is selected the relevant controls for the selected device appear If a failed device or a static spectrum is selected the system will display all the controls but they will be grayed out indicating that they cannot be modified The seven tabs provide access to the Preamplifier and bias controls PreAmp Bias Amplifier controls Amp
64. LOW Bu ROI BACKGROUND HIGH G PEAK GAP G GAP Fig 1 Region of Interest and Associated Continuum Regions PK The continuum correction is made by calculating a straight line subtraction of the continuum spectrum in the neighborhood of the peak The number of channels in the background region on each side of the peak and the spacing between the background region and the ROI are controlled by parameters set from the Tools Setup menu and stored in the spectra s header Quantum Note To override the automatically set continuum background regions set background type ROIs in the spectrum Manual background regions can be anywhere in the spectrum and of any width How continuum regions are set in the spectrum is controlled by three parameters which are stored in the spectrum header Some PGT software allows the user to adjust these parameters others use fixed values of these parameters The control parameters are shown in the following table BKGwidth Width of the Continuum Background region on either side of the peak This number is stored in terms of channels BKGspread Gap between the ROI and the Continuum background region If the spectrum uses a linear energy scale as indicated by ADCconvmode 0 then this value is a multiplier of the FWHM for the peak Otherwise this value is expressed in channels ROlvvidth Full width of the ROI If the spectrum uses a linear energy scale as indicated by ADCconvmode
65. M 6 Baud Rate 19200 ae Initial selection Search Results 1 4 1 Choosing a Connection Device You can use the following methods to connect the Quantum MCA products to your computer Serial port see Serial Port on page 3 e Plug in Cards see Plug in Cards on page 3 GPIB IEEE 488 see GPIB IEEE 488 on page 3 Ethernet see Ethernet on page 4 1 4 1 1 Serial Port To connect your MCA to the computer using one of your computer s RS 232 COM ports select ANS COM and the appropriate port COM 1 COM 2 COM 3 or COM 4 Older versions of Quantum prod ucts operate at 19200 baud Newer versions have adjustable baud rates Make sure the rates set in the hardware and software match Note that for Quantum products with a firmware display and printing capabilities the selected baud rate will also affect communications with the printer 1 4 1 2 Plug in Cards The Quantum software now supports Oxford Tennelec PCA3 and PCAP plug in cards These cards are not supported on any operating system based on Windows NT technology 1 4 1 3 GPIB IEEE 488 The Oxford Tennelec PCA M GPIB Multiport units are supported if the latest 32 bit IEEE 488 driver for Windows has been downloaded from the National Instruments web site www ni com Quantum WPGT PRINCETON GAMIMA TEGH After downloading and installing the software for the appropriate IEEE 488 controller card installed in your PC follow the instructions
66. NCETON GAMMA TEGH e Click Execute EM Manual Multi Point Calibration ROT Centroid Standard chrn kev Err 27 089 120 1 20 365 800 1 10 124 300 1 2 931 000 783 2 265 100 J 2 220 0001101 0001411 Enter Energy of Each Line to be Included in Calibration Energy ROI Linear f Previous Next 1408 0 Execute tv Quadratic The errors associated with the fit will appear in the display 6 3 3 Manual Resolution Calibration The Manual Resolution Calibration lets you manually perform either a linear resolution calibration or a quadratic calibration of the form Resolution A B E C E It is very important to perform a manual resolution calibration of your system in order to obtain accurate analytical results To run the calibration e Choose Setup Manual Calibrate Resolution Calibration to open the Detector Resolu tion Calibration dialog box below e Select each peak you want to include in the calibration by left clicking its name in the list and clicking Include to use it in the fit You can also use the Next or Previous buttons to move through the list Click Remove to delete a selected peak from the list A full height marker appears on the main spectrum display indicating the peak selected For a better view of the spectrum during peak selection move the dialog box out of the way or minimize it After you have selected all the peaks select either a Linear two point or Qu
67. PGT Detector Efficiency Model PRINCETON GAMMA TECH Appendix B Detector Efficiency Model Many different approaches have been used over the years to compute detector efficiencies Most soft ware packages have approached the problem by fitting a function of some type to the measured effi ciencies of a set of known standards The functions used have been many however the most common have been Polynomial in Energy a E where normally 1 would range from 0 to 1 2 or 3 1 Polynomial in 1 Energy Za JE where normally 1 would range from 0 to 1 2 or 3 Polynomial in Log Energy Za Log E where normally 1 would range from 0 to 1 2 or 3 All of these empirical models suffer from the problem that the efficiency of a detector can change very rapidiy at low energies A behavior which none of these equations can model well These empirical models vvere adopted because the calculation of detector efficiencies from first princi pals is extremely complex and computationally intensive In this software we approach the problem from a different point of view Personal computers are now sufficiently powerful to allow us to model the principal effects causing the energy dependence of the efficiency At low energy the efficiency is dominated by the effect of absorp tion in the windows of the detector and in any dead layers At higher energies the main effect is the detector s ability to absorb the incoming radiation At all energies the ge
68. PGT Quantum Family Software Users Manual Version 4 04 00 Princeton Gamma Tech Instruments Inc Nuclear Products Group 303C College Road East Princeton NJ 08540 609 924 7310 www pgt com Quantum Software User Manual PGT PRINCETON GAMMA TEGH PGT Quantum 4 04 00 02 00 Copyright 1993 2001 Princeton Gamma Tech Instruments All rights reserved The following are trade marks or registered trademarks of Princeton Gamma Tech Instruments formerly American Nuclear Sys tems Inc Quantum QuantumGold QuantumMCA Quantum Explorer Quantum Assayer Quantum WTC Quantum FDA Quantum LIB and Quantum X Printed in U S A TRADEMARK ACKNOWLEDGMENTS The following are registered trademarks of the companies listed Excel Visual Basic Access Windows 95 Windows NT Microsoft MS DOS and Windows Microsoft Corporation Intel Intel Corporation PCAP PCA3 Multiport Oxford Instruments Inc Other names are trademarks or registered trademarks of their respective holders PRINCETON GAMMA TECH pct IMPORTANT PLEASE READ CAREFULLY BEFORE USING OR COPYING THIS SOFTWARE NOTIFICATION OF COPYRIGHT THIS SOFTWARE IS PROTECTED BY COPYRIGHT LAWS AND INTERNATIONAL TREATY YOU MUST TREAT THE SOFTWARE LIKE ANY OTHER COPYRIGHTED MATERIAL COPYRIGHT LAWS PROHIBIT MAKING ADDITIONAL COPIES OF THE SOFTWARE FOR ANY REASON OTHER THAN SPECIFICALLY DESCRIBED IN THE LICENSE BELOW YOU MAY COPY THE WRITTEN MATERI ALS ACCOMPANYING THE SOFTW
69. PRINCETON GAMMA TECH 1 7 1 Selecting Spectrum Display and Memory Control Parameters 1 Left click the Memory button left on the toolbar to open the Spectrum Display and Memory TO Control dialog box This dialog box is used for a variety of memory selection and display con trol operations The example below shows the current contents of the available memories Spectrum Display and Memory Control DISPLAY PRI ENA MEMORY STATE ID FILE NAME or DEVICE 1 Live Device SAM905D 01 File 2 Static MGS1 1043 Eu152 2836755 Eu154 3885677 Eu155 3070863 052131 File 1 1043 1 3 Static MGS 2 SN 1060 Mn54 14800 Co60 5555 Sb125 5380 Eu155 4180 File 2 1060 1 4 Empty 5 Empty Emo 7 Empty e Emo The Spectrum Display and Memory Control dialog box contains the following five columns Display PRI Designates one primary spectrum always displayed in the primary spectrum color white in the PGT default colors Display ENA Enables the display of a spectrum The primary spectrum is always displayed and you can select additional specific spectra for display Memory Allows selection of memory buffers to be cleared When selected the entry displays in red and a Free Selected button appears Click the button to erase the selected memory and make it available empty State The system recognizes four states for a memory Empty Static Live and Failed See the list below for a description of each one
70. Quantum EPGIT PRINCETON GAMMA TEGH 102 Length information could not be read A communication packet for the current communication protocol requires an indication of the packet length and there ware a problem trying to read this information 103 Packet was not long enough A packet of known length was expected and only part of it was received This might indicate a faulty or disconnected cable 104 Packet checksum did not match This communication protocol supports a checksum for error detection and the check failed This usu ally indicates a temporary transmission error 105 Packet did not end correctly A communication packet arrived without the trailer information required by the protocol 106 Timeout during communication This is one of the most common errors and it usually indicates that a device is not online or a cable has become detached Check for these conditions and retry the operation Some devices including the PCA Multiport occasionally hang and need to be reset in order to resume normal communica tions 107 Received break character A break character a long sequence of one bits for the RS 232 communication protocol was detected This most commonly occurs when the baud rates of the two devices trying to communicate are not correctly matched 108 Received parity error For a protocol that supports parity checking this indicates a parity error in transmission 109 Received framing error The seq
71. Same as pressing the Acquire button in the main tool bar CTRL T Stops data acquisition Same as pressing the Stop button in the main toolbar CTRL R Erases the primary spectrum Same as pressing the Erase button in the main toolbar CTRL K Selects the Isotope drop down list orT Moves to the next isotope in the Isotope drop down list or 4 Moves to the previous isotope in the Isotope drop down list HOME If the spectrum view is expanded moves the view region to the lowest possi ble energy range END If the spectrum is expanded moves the view region to the highest possible energy range PGT Main Display PRINCETON GAMMA TECH 2 Main Display The main spectrum display window contains the following sections Title bar Menu bar e Toolbar Spectrum display area e Auxiliary display or data panels e Status bar Detailed descriptions of all the capabilities of the Menu bar functions can be found in Sections 3 8 Library in Use Title bar Primary spectrum info jew s Analysis T Tools Help Em MEDE 1 GAMMALIB MDB GAMMALIE MDB ulei Lin Log Sat un 500 00 s ak O ELT 3426 6 cps Rate 24 W Spectrum display area Auxiliary spectrum vertical expand contract unu Ts hannel Tez c Counts nts EP ROL 21 Centroid TE E Status
72. T View Menu Options 41 PRINCETON GAMIMA TEGH e Click Clear All to reset all offsets back to zero e Click OK to save the values and close the Spectrum Display Offset dialog box 5 2 Spectrum and System Setups Choose View Setups to open the View Setups dialog box and display all the setup parameters for a selected spectrum for a device unit or for the system The information is displayed in a text window as shown below Ed View Setups EI File Spectrum 0 9 9 9 is System Data Header for Spectrum 4 Spectrum ID MGS 2 SN 1060 Mn54 14800 Co60 5555 Sb125 5380 Eu155 4180 File Name 2 1060 1 Start Acquire Stop Acquire Elapsed Live Time 300 00 Elapsed Real Time 312 26 Elapsed Counts 0 0 Elapsed MCS Passes 3254 00 Average Dead Time 3 93 Presets Presets are Off Preset Live Time 0 secs Preset Real Time Preset Peak Preset Integral of All ROIs 0 Hardware Parameters Hardware Device at Bus Address Unit 4 Connected as Port O using device handle 0 Click the appropriate spectrum number in the Spectrum panel to view the information corresponding to a specific spectrum Select System to view system information The File menu contains three options Save az Text File Print Report Exit e Choose Save as Text File to save the information in the View Setups dialog box to a spe cific text file e Choose Print Report to print the contents of the panel e Choose Exit or click Exit to
73. Time Mode 0000 0000 000B IMMM B pos ADC busy out 1 pos ADC deadtime in MMM 0 simple busy 1 Loves 2 Gedcke Hale 3 extern Type of conversion 0 Lin 1 QCC MCS Mode 0000 0000 SAPa IIII S extern sync A pos ext adv pol P pos ext pulse pol a ext advance I 0 internal 1 SCA 2 ICR 3 ext 4 ROL Bit settings for external ADC PCAX etc Bit settings of external outputs ADC Zero Adjust Low Level Discriminator Upper Level Discriminator 256 512 OLA z 400 0512 62a Current Group ADC Digital Offset Gain Stabilizer mode 0 off 1 edge 2 ROT Gain Stab start region Gain Stab end region Gain Stab associated ROI number Gain Stab Current Value of correction Gain Stab Time period seconds Gain Stab Range of Correction Zero Stab start region Zero Stab end region Zero Stab associated ROI number Zero Stab Current Value of correction Zero Stab Time period seconds Zero Stab Range of Correction Dwell time or sample interval seconds REV2 Number of passes for MCS Reserved for ADC expansion HPGT PRINCETON GAMMA TECH Hardware Setup Presets PresetON As Integer 0336 RSRV0338 As Integer 0338 PresetRT As Long 0340 PresetLT As Long 10344 PresetPK As Long 0348 PresetCount As Double au PresetCntROI As Integer 103601 PresetCntMode As Integer 0362 RESV0364 0 To 3 As Byte 0364 Devname 0 To 15 As Byte 0368 devtyp
74. To place a spectrum annotation Hold down CTRL SHIFT and left click on the spectrum display where you would like the annotation to appear The Annotation Editor dialog box below will open Annotation Text Next Previous Delete Clearall 4 gt e e Enter the annotation text and click OK To identify lines e Hold down ALT and left click at a point in any energy calibrated spectrum The software will locate the characteristic radiation lines nearest that energy and display them in a pop up window This provides a quick way to identify possible nuclides e f you are trying to identify a peak ROI simply click on the center of the ROI and then click on the desired nuclide line listed in the pop up window This will assign the nuclide to the ROI 1 8 3 Right Mouse Button You can use the right mouse button in the following ways To drag to expand a region of the spectrum e Press the right button and drag out the gray region to select the expanded view e Release the button To click to a center point e Hold down CTRL and click the right mouse button to make that point the center point on the screen f the current horizontal expansion is set so that the selected point cannot be made the center for example if you are viewing full scale and click at 1 4 scale there will be some expansion but the point will not be exactly centered To click to a center point and expand e Hold down CTRL SHIFT a
75. XXX is Ge GeD Gold MCA Nal or NalD depending on what you have purchased Click OK Your CD ROM drive may be E G or some other letter rather than F Use whatever letter is appropriate for your system You may also use the Add Remove Programs icon in the Control Panel window The default directory for Quantum installation is C Program Files PGT Quantum You may choose a different location if you want Answer the on screen questions during the installation 1 3 1 Directory and Path Quantum automatically creates the following directories during installation C Program Files PGT Quantum is the root directory It contains all executable files C Program Files PGT Quantum Data is a data subdirectory lt contains configuration files report files standards and other data files C Program FilesiPGTiQuantumiLibs is a library subdirectory It contains several nuclide databases used with Quantum C Program Files PGT Quantum Manual contains the complete users manual in PDF format You must use Adobe Acrobat to open and read this file C Program Files PGT Quantum Qscript contains the source code for Qscript C Program Files PGT Quantum Spectra is the default location for storing spectra metafiles reports and ROI and system configuration files C Program Files PGT Quantum Temp is used for temporary file storage during the construction of reports and other similar operations 1 4 Hardware Communications Setup Procedure Before r
76. adratic multi point calibration e Click Execute WPGT Setup Menu PRINCETON GAMIMA TEGH The FWHM value for each peak is computed using a smoothed linear interpolation technique When a fit is executed the errors associated with the fit will appear in the display gs Detector Resolution Calibration File Centroid Include FEHH ker calc Click Include to Select Current Peak ROI Cl p Previous Next ie ad Execute 6 4 Detector Parameters Quantum has a sophisticated detector model that allows accu ss Detector Parameters Ea rate efficiencies to be calculated Detector Designation T over a broad energy range for a wide variety of detectors The Nal 7 7 ling Detector Window Parameters soun 7 Material Thickness pm HpGe N Detector Efficiency Model It is Window 1 A 01 very important that the correct l parameters be selected for the Window 2 None foo detector you are using The soft Window 113 None 0 0 Dead Layer ware is shipped with a variety of l Thickness um detector types in its database You Window 114 None z oo 700 00 can select one of these if appro priate from the Detector Cylindrical C Well v Coaxial Description menu If necessary you can also create your own Diameter 1 65 icm Well Core Diameter 0 80 em detector type or modify one of the Thickness po n Well Core Depth oo m 15 pth
77. ame to which the dead time is saved Selects which memory to control Prompts for name and saves the spectrum X in the Spectra sub directory Prompts for a spectrum ID Copy spectrum from one memory to another Reports the number of channels in the message line Opens File selection panel select SomFile txt file Opens File selection panel select id txt file Prompts for ROI number and reports net activity in message line GetCounts GetCounts Reports the maximum counts in the primary spectrum in the message line Quantity SampleQuantity quan Opens File selection panel select wt txt file tity As Single Units SampleUnits units As Opens File selection panel select units txt file String As String Date SampleDate Activity Opens File selection panel select date txt file Date As String As String Time SampleTime Activity Time As String As String Opens File selection panel select time txt file PPGT QScript 95 PRINCETON GAMMA TECH Command i E Loops Begin End AutolD AutoSave Preset Interval Input Msg External Program Call Wait Analysis Select Library Get Library Analysis Method Analyze Print Report Save Report Use Library Efficiencies LoadConfigY ANH DoNumPass X LoopBeg LoopEnd AutolD AutoSaveSpc SPEC WaitPreset WaitSeconds XX VVaitDig 1 XX VVaitDigMessage CallExtProgxXX WaitExiProgXXX SelectLib GAMMALIB MDB GetLibrary GetUseLibEff AnalyzeProgram Pr
78. an Up arrow at the right of the title bar The Restore button appears after you have enlarged a window to its full size Mouse users can click the Restore button to return the window to its previous size Other users can use the Restore com mand on the Control menu ROI Controls A data panel allowing creation definition and editing of regions of interest Root Directory The highest directory of a disk The root directory is created when you format the disk From the root directory you can create other directories Scattering Change of direction of subatomic particle or photon as a result of a collision or interaction Scroll Bars The bars at the bottom and right edge of a window whose contents are not entirely visi ble Each scroll bar contains a small box called a scroll box and two scroll arrows to allow different types of scrolling Scroll To move text or graphics up or down or left or right in order to see parts of the file that cannot fit on the screen Secular Equilibrium An equilibrium condition in which the decay product daughter nuclide has a much shorter hal life than the parent nuclide and the daughter nuclide activity increases in an expo nential manner governed by the daughter s hal life The equilibrium ratio of the activities is essentially unity Secular equilibrium is commonly observed in the natural decay series Select To highlight an item by clicking it with the mouse or using key combinations Selectin
79. annel but be aware that this may confuse opera tions such as autoscaling The ignore setting is more commonly used and is often the only one avail able Some devices which provide a linear gate output or a peak detect output allow you to set the polarity of these outpuis Stabilizers EstemalContols Presets ADC Zero ADC LLD ADC ULD i Group Number Conversion Mode x x x Group Size LINEAR 0 061 0 000 00 050 fi 6384 zi C acc Cony Gain fi 6384 The ADC2 panel provides controls for the ADC zero adjust the lower LLD and upper ULD level dis criminators ADC digital offset the group size and conversion gain the group number and the opera tion mode most commonly PHA or MCS though some devices also support SVAH sample voltage histogram and SVAL sample voltage list modes The group size refers to the number of MCA chan nels Click the spin box to change the number of channels The maximum is controlled by your hard ware Some PGT devices also support a choice of two conversion modes linear the default mode or HpGT Main Display PRINCETON GAMMA TECH e PGT s patented Quadratic Compression Conversion US Patent no 5 608 222 a mode par ticularly appropriate for scintillation spectroscopy 2 3 4 Stabilizers On PreAmp Bias Amplifer abc
80. are trying to achieve The following table lists the COMM commands used in QScript 97 QScript T PRINCETON GAMIMA TEGH P S ld D UOP H JON 10U SEM JON In ss oons sem 48510 MO 10U SEM ATI JON In ss oons sem lqEuz MO SE 14 payie4 pojiea INJsseoons SEM SE14 MO dois payie4 QAI 10U Sem oww OA ION InIss ons sem eJinboe dois HE1S 0 uonisinboy pojtea 4 Hnq AH uou OU nboe o pou ATI ION InJsseoons sem eJinboe ues MO peo 1 55900 5 MO Palle PEO 25 peol LUPINOO Buys jdus sem Ailo ds ISNIA peo NnJsseoons AMO PEO Jopeou PeO LUpjnog Buijs jdus sem jioods ISN wunsjoeds Mewnud Buas iniss oons a6ues ul jou JoqunN winjoeds pijeau lli IOH ue 10 SWBUyjed pijea oweu y JO e 41 anjea AUY dm s joo S OOL 9 1010 puke suogeigijeo eo 9 MH O UON BINDIJUOD OU JO sped UO UM S H S eym ofl UOIEINBYWUOS e JO weuyed P EA OWeU Hnq
81. areas that you know contain only background noise Because it detects changes in the second derivative it is sensitive to dips and spikes even at very low intensities A good way to cut down on these peaks is to take advantage of the Uncertainty cutoff which requires the peak to be clearly different from the background In the Low Pk To Bkg mode the Integral and Power are proportional to the net intensity and mean value of the peak and allow you to keep or eliminate weaker peaks as necessary 6 7 Selecting a Report Font Quantum displays many reports for example Setups Peak Reports and Identify Reports within scroll ing text boxes To correctly view these reporis you must display them in a fixed spacing font Although the only standard fixed spacing font in Windows is the default Courier New many systems have fonts that will display better on the screen Use the Setup Select Screen Report Font option to select such a font If data lines wrap Decrease the font size to line up the columns properly OR Expand the window by pressing the left mouse button on a window corner and dragging Click on the font style and size selections The sample box will show how the selections look Click OK to apply the selection Changes made in the Select Screen Report Font do not affect the fonts used by the printer 6 8 Selecting a Display Color The default colors of the display area the spectra and the other display items can be cha
82. arying Confidence Intervals Background regions are automatically computed based on the ROIs set by the Peak Search tool The Width setting determines how many channels are set in the region on each side of the peak The Gap parameter determines whether the background region channels are immediately adjacent to the peak ROI or separated from them The separation is measured in units of FWHM and is energy dependent This feature is particularly useful in adjusting background regions to different types of specira Background Parameters When using linear MCAs the ROI width and gap are expressed in terms of multiples of FWHM For Nal spectra using linear MCAs these are good default choices ROI width 2 5 x FWHM Background width 1 channels Background gap 0 x FWHM When a QCC based MCA is used all peaks have the same width in channels so the ROI width and gap are expressed in channels rather than as a multiplier of FWHM The Tool Setup dialog will change to show the ROI Width and Background Gap in channels When the maximum energy is set to 2048 keV all peaks will be approximately 11 to 13 channels wide at the base For Nal spectra using QCC devices these are good default values ROI width 13 channels Background width 1 channels Background gap 0 channels Manual Background ROI Capture Range The Manual Background ROI Capture Range is similar to the Energy Window Manual Background ROI Capture Range Channels 72 62 Quantu
83. ate by ROI centroids 87 resolution 88 two point energy 52 86 mathematical algorithms 103 MDL parameters 62 memory buffer free 8 memory control see spectrum display control metafile 31 multi channel scaling 27 N nuclear library clone 39 editor 37 nuclide information reports 39 nuclide lines enable 37 134 Quantum O overlaid display 12 P peak identify 71 89 manual 19 peak search 70 89 peak width FWHM 60 preseis 26 primary spectrum 8 info line 14 printer setup 33 Q QCC 24 QCC Quadratic Conversion Compression ROI width 61 QScript commands 93 quadratic conversion compression see QCC qualitative analysis 89 quantitative analysis 90 ROl directed 91 with deconvolution 90 Quantum MCA version number 75 R rapid scan 90 rapid scan analysis 2 Region of Interest see ROI reports 1 by line 71 fonts 64 setup 33 resolution default peak widths 56 resolution calibration 47 ROI background capture range 61 parameters 61 clear 21 create 78 current 21 data report 68 detail report 68 edit 21 78 files 33 foreground 21 labels 21 manual create 9 manual identify 79 peak search 70 tool bar controls 20 PRINCETON GAMMA TEGH tool bar display toggle 41 width 60 S sensitivity 59 spectrum acquire 80 auto vertical height 77 calculator 66 copy options 35 expand 77 header information 115 load 29 load options 76 peak search 70 PGT file structure 115 qualitative analys
84. bar ROI tool bar 11 12 Quantum PRINCETON GAMMA TEGH The Spectrum display area can include up to eight spectra at a time Multiple spectra dis played in overlaid or tiled modes These display modes allow one region of the screen to be automati cally managed by the program providing virtually any user preferred data display Quantum Note In overlaid mode if there is no data in the primary spectrum for example when that memory buffer is connected to an MCA device that has not acquired any data but there is data in another memory you may think the system is broken when the cursor fails to read out the data from the spectrum you can see The primary spectrum is always shown in the primary spectrum color white in the default colors and its info is displayed Examples of the two modes are shown below i hh wh the t l L Reb sell 7 in My ft ul fly iy A AL id k E E j h UM f Al i 1 Ny 4 ne Overlaid mode All enabled spectra are displayed Tiled mode The spectrum display area is divided overlaid on one another in the full spectrum area into horizontal bands Each enabled spectrum is displayed in one of the bands The Auxiliary display area has four modes The auxiliary spectrum display of the full primary spectrum as shown in the sample screen on the preceding page A spectrum convolution display
85. bsequently changed by analysis programs Corr is the cross correlation value which is computed by the peak identify routine and by certain of the analysis routines It may be viewed as a probability that the line has been properly identified Hits is the number of lines is the database which could match this line A 3 Peak Finder PGT software employs a peak finding algorithm based on convolving the spectrum with one of several filters and then searching the result for positive lobes of sufficient strength There are three types of fil ters available 1 second derivative 2 simple top hat 3 variable width top hat The second derivative filter has the ability to detect overlapped peaks provided the overlapping peaks are partially resolved however it is not very effective when the peaks are broad or noisy The top hat filter is excellent at finding very weak peaks however it will not detect as two partially overlapped peaks The top hat fil ter s sensitivity is also strongly affected by the width of the filter compared to the width of the peak For maximum sensitivity the filter needs to be matched to the width of the peak Case 3 the variable width top hat filter attempts to optimize performance by adjusting the filter width to the measured resolution of the peaks in the spectrum This is the filter of choice for most spectra Peak Finder takes an input control structure which determines which filter will be used what order of filter will be
86. button to match the number of the device to be controlled If there is just one MCA card or device the default of 1 is correct Click on Pri mary to select this device Notice that the command was added to dE SE Ts the text in the edit window As you click Fie Connect the command buttons in the order that they are to be executed each command is added to the edit box The commands ie a T Primary will also be immediately executed by m E ee i Show Msg steels in surp it mistakes seme save nal s sri ue effects of the script If a mistake is K r FOR Gotas ati eal Es pal Beep Spectrum Load made that command can be changed Save Set ID Co HChannels Config _ Maximize or deleted using the normal editing dan capabilities in the edit window Press the Quantity Units Date Time View ROI right mouse button to see the editing commands o Begin End AutolD AutoSave 5 z mi P Mif ait External Program Continue to click command buttons n Preset nterval Input Hg Call Wait the order that you wish the Script file to SEE uzu em val gelin play them later As each command but Select Library Print Report Het Name u ton is activated the command is tested Get Library Analyze Save Report and the command text is added in the Alphaib mdb P Use Library Efficiencies edit box Once you have entered all the steps in your script click Save S
87. cale energy in keV If you want to use a different value select User and type the new value directly into the User text box To see the composition of the selected standard click Edit New Standard to open the Edit Standard dialog box See Creating and Editing a Calibration Standard on page 44 for a description of the com mands contained in this dialog box Click OK to exit 44 Quantum WPGT PRINCETON BAMMA TECH 6 2 2 Creating and Editing a Calibration Standard The Edit Standard dialog box contains commands allowing you to create and edit standards The text fields contain information corresponding to the currently selected standard s Edit Standard ID Mast 073 Date 10 10 1994 MMOD AY yy Nuclide Activity Mn54 0 55 Cob0 0 11 Eui hh 0 11 sbi25 0 19 Activity Activity Uncertainty Units 32 uCi E Delete New Save Preset Live Time To edit data e Click New to clear all the fields Inthe Date box enter the assay date and select up to six nuclides from the submenu listing the contents of the currently selected library Enter the Activity of each nuclide This information is obtained from the source documenta tion e Inthe Activity Units box select the units e In the Preset Live Time box enter the preset time to use for data acquisition when this source is used for calibration This time must match the actual spectrum acquisition time e Inthe ID panel enter a
88. cause of the low peak to background ratio The Quadratic Compression Conversion QCC system solves both problems by having the channel width of the converter at a particular energy be proportional to the energy resolution of the system at that energy In a QCC Nal 1T1 spectrum all peaks have the same FWHM expressed in channels independent of energy QCC technology can cover the entire energy range of interest with enough resolution to provide accurate spectral analysis while providing enhanced minimum limits for identification PG T Setup Menu 49 PRINCETON GAMIMA TEGH Select the Quadratic Compression Conversion QCC mode in the Conversion Mode panel in the ADC2 tab of the Hardware Controls dialog box Clear low energy peaks j High energy peaks hard to see Low energy peaks still undistorted Clearly visible high energy peaks o In 1000 1500 20000 Spectra of Eu152 top 1024 channels with linear compression bottom 512 channels with Quadratic Conversion Compression 6 2 7 Efficiency Calibration If you are using Quantum for quantitative analysis you must perform an efficiency calibration This cal libration allows you to calculate the individual line efficiencies for a particular standard If the primary memory contains data you will be asked if you want to use this data or take new data for the calibration process If the memory is Static the spectrum currently contained in the primary memory is used allow ing calibrati
89. ch as Nuclide or UNK XXX X Table 7 1 ROI Details PRINCETON GAMIMA TEGH er Quantum Start Chan First channel in ROI m nel ciano tusisasinso contr tonn sila n n is n m s l ond Moment Second moment of the ROI 3rd Moment Third moment of the ROI Gross Gross counts in the ROI and its error Counts HPGT Analysis Tools 69 Ambient Counts in the background spectrum in this ROI corrected for live time X Background ratio and its error Continuum Continuum counts based on a straight line between background ROls Background and its error Net Counts remaining in Peak after all corrections have been made and its Counis error Activity Activity of isotope associated with this peak and its error X MDA Minimum detectable activity X Nuclide Nuclide assigned to this peak Correlation Correction produced by Peak Identify or Search based analytical routines Library Matches Result of Peak Identify or Search based analytical routines the number of lines in the library which match this peak in energy Finder The integral of the positive lobe of the filter function used by Peak Integral Finder controlled in Tool Setup by Integral setting Finder Power Integral of the positive lobe of the filter function divided by the width of the lobe controlled in Tool Setup by Power setting Efficiency Detector efficiency for this energy X Intensity Radiation intensity and its error fro
90. ciencies enabled If the library name is in red Use Library Efficiencies has not been selected Show Hide Markers shows or hides nuclide line markers for the isotope selected in the Isotope drop down list Jacaza These are the markers used in manual peak identification The specific isotope lines that are labeled depend on the selected library In general standard detectors use NAILIB MDB and well detectors use WTCLIB MDB PPGT Main Display 19 PRINCETON GAMMA TECH Show Marker Menu opens the Markers dialog box where you select the type of marker to be Lil displayed You must choose one item in each rovv The current selection is displayed in red Markers Proportional Tall To Spectrum User Selected All Lines No labels Nuclide Nuchde E nergy Line amp Tag Tag Only Either click on the item you want or click the icon on the left to move through the selections The commands in the Marker Height row set the relative heights of the markers drawn on the screen You can choose e Height proportional to the intensity of the line Proportional Exaggerated low intensity lines Tall Height matching peak To Spectrum The commands in the Lines Displayed row allow you to select the lines to show on the display You choose Only lines in the library where the use box is checked User Selected e All lines in the database All Lines mm The commands in the Ma
91. column sb125 E enter the activity from the documentation that came with the standard 6 Enter the Activity Units Activity Activ that correspond to those eo Uncertainty Freset Live Time 76 Activity values uCi E P 300 7 Enter the Preset Live Time that vvill be used for system Delete New Save calibration The time entered here must be the time actually used to collect the spectrum that is the software will not correct if the time entered here does not match the time used in acquir ing the spectrum 8 The uncertainty in is taken from the documentation 5 is usual 9 Enter a descriptive name in the ID field 10 Enter the calibration date of the standard current date if not calibrated 11 Press Save and then Exit The standard can now be used to Auto calibrate your system with that source 1 f you do not have QuantumGold you can use a non calibrated source but you must enter dummy activities e g 1 in the Edit Standard dialog box 86 Quantum PRINCETON BAMMA TECH 9 11 Manual System Calibration The software lets you do the manual hardware adjustments and manual calibration as well In the Hardware Controls PreAmp Bias tab enter the target bias voltage and click Enable 2 Inthe Hardware Controls ADC2 tab enter the Group Size Select the full energy range from the Setup Manual Calibrate menu 3 Puta source in front of the detector In the Amplifier tab sel
92. commands used to edit the follow im 0 Refresh Rate During Live Acquisition Refresh Rate During Live Acquisition As Rapidly as Possible As Rapidly as Possible results in rapid spectrum update Update Every E Secs but may result in sluggish behavior for controls Display Units Selection Except for special circumstances a setting of 2 3 seconds for the refresh rate is recommended PHA Mode MCS Mode axis Units kev s Display Units Selection axiz Label Energy Time Defaults These fields allow the software to be used with non gamma ray spectroscopy applications Many of the internal features of the software such as the libraries and the calibrations Spectrum Information use fixed units of keV or channels The units entered here 12 Clear with Spectrum Erase are the units that will be displayed on the x axis of spectrum plots Spectrum Information Select Clear with Spectrum Erase to clear all spectrum information fields whenever a spectrum is erased Beep when Preset Reached when selected causes the system to beep three times when spectrum acquisition reaches preset Click Apply to apply the changes Click OK to exit 4 3 Edit Screen Annotations To add an annotation to the spectrum display Bring the pointer to the appropriate location Press SHIFT CTRL and left click The Annotation Editor dialog box will open e Enter the text and click OK The text will appear in the dis
93. cript This will bring up a standard Windows file save box with a default file extension of QSF Quantum Script File The file is saved as a text file so it can be edited with any text editor such as NotePad Once saved a script file can be loaded Load Script Save Script Erase Script Play Script and played as needed To test the script running automatically click on Play Script To invoke a saved script from a batch file or other program you can use the QScript program with the script file as its first argument and it will run the specified script exiting automatically when done f you plan to run a particular script often you can make an association with the QSF file type which will run QScript when you click on the script file Be aware that not all MCA devices support all the available script commands Because of this the example script files included with this disk will not run on all MCA devices 94 Quantum PRINCETON GAMIMA TEGH The following table lists the buttons on the QScript demo screen each of which represents one of the commands that are available in the scripting language Commands whose names appear in brackets are COM commands supported by the Quantum MCA software and can be used from any COM appli cation connected to the MCA program The other commands are interpreted by QScript and you may need to copy the implementation of these if you are writing your own controlling application Som
94. ctrum as a green line and the reconstructed spectrum as a red line When you expand the main display to show an overlapped peak this Deconvolution display will change similarly PFA 8 Tea Fa LL E Quantum EE Edit View Setup Analysis Tools Help m m ng108 Es z ELT 50000 Rate cps 2 Static 110491 A 152 l A Energy 1193 Channel 950 Counts 470 ROI Met Integral Centroid Click on one peak in either the main display or the Deconvolution display to make it the current ROI The Deconvolution display will show that peak as white To eliminate one of the ROls from the analysis click on it to make it the current ROI Click Delete ROI and then click Reanalyze to redo the analysis 74 Quantum ElpisiT PRINCETON GAMIMA TEGH If you close the Deconvolution display a Show Deconvolution Display button appears at the upper right of the toolbar Click this button to redisplay that window Yyl 7 10 Analyze ROI Directed In the ROI directed approach the user assigns a nuclide to each ROI in the spectrum This can be done through the Rapid Scan function by manually creating and identifying peak ROIs or a combination of both An ROI can cover a single line a multiplet of lines or several unresolved lines the four Ba133 lines from 286 keV to 384 keV which form a large glob on Nal systems To determine the theoretical intensity of the ROI the system searches the library for
95. d As Single Centroid no BKG Correction Peak As Single Peak location in ROI no BKG sub FWHM As Single FWHM w BKG correction End Type One structure is stored for each ROI The number of ROI structures is found in NROIs 120 Quantum EPGT PRINCETON GAMMA TECH This page intentionally blank HPG T VVarning and Error Codes 121 PRINCETON BAMIMA TEE Appendix D VVarning and Error Codes Many of the internal operations of this software package are designed to return informative failure codes in the event of a problem All of these internal error codes are represented by negative num bers while success is represented by a value of zero This section gives names for the defined error codes and explains some of the circumstances under which they might occur Some of these errors shown with the bug marking represent error codes that will usually not occur unless there is a bug in the software If one of these error codes is encountered please contact us so that we may help you solve the problem General Errors 0 to 99 0 No error This code represents successful completion and so should never appear in a warning message a 1 Other error x This represents an unexpected error type that could not be categorized in any other vvay 2 Could not allocate memory If an operation required more memory than was available either because free memory was too small or because the request was unreasonably larg
96. data window with info for the selected ROI this View ROI ith i thi simply demonstrates the use of GetROlData command and is not used in scripts Make the MCA screen large 1 Sample Puts message up on screen for a time change complete Table 10 1 Some notes on the various commands 1 If you click On in the Presets section be sure to click Preset in the Wait section after you enter Acquire into the script Otherwise any subsequent commands will be carried out before acqui 96 Quantum PP GIT PRINCETON GAMIMA TEGH sition is complete 2 The various Set commands will open a dialog box for you to enter a value or a file name The same is true of the Dead Time button 3 When you enter Get ID or Get Name into a script you must select a text file with the spectrum ID name or report name These can use the same file To create this file open NotePad or other ascii editor The contents of the file is the name you want to use It does not need to include the extension and therefore can be used for both the spectrum name and the report names Save it with a suitable file name to the Quantum folder or one of its subfolders Similarly you must create txt files for Quantity wt txt Units units txt Date date txt and Time time txt in the Spectrum section 4 Inthe Spectrum section Save opens a dialog box for you to enter a spectrum name and then saves the file to the Spectra folder Get Name takes the name from
97. ding tools used in the software depend on convolving the spectrum with some type of filter function Select the filter type in the Mode panel For calibration use Low Pk to Bkg and then change the Mode depending on your detector and analysis requirements Overlapped mode uses a second derivative like convolution operation It works well for spectra with relatively narrow peaks usually less than 25 channels FWHM that may have some overlap It will gen erally resolve two overlapping peaks if there is a noticeable inflection point t does not work well in spec tra with broad peaks or where channel to channel statistics are poor This is the usual setting for germanium detectors or Nal detectors in QCC mode The Low Peak to Background Low Pk to Bkg approach uses a variable width top hat filter whose width is optimized to the FWHM of the spectrum The system breaks the spectrum into regions and applies a top hat filter to each region The width of the top hat filter is related to the FWHM of the peaks in the region This approach is very sensitive to peaks with minimal data but is not adept at resolving overlapped peaks A fundamental limit on the algorithm is that the maximum width available for the top hat filter is 101 channels If the peaks are wide compared to 101 channels then the system may fail to find these very broad peaks Low Pk to Bkg is recommended for Nal detectors PPGT Setup Menu 59 PRINCETON GAMMA TECH For maximum effectivenes
98. don the document in a document window before you close the application Coincidence Summing Two or more gamma rays emitted from a single nucleus within very short time frames lt 1 07 s and with a preferred angular correlation This process in conjunction with count ing geometry gives rise to coincidence sum peaks Coincidence The occurrence of counts in two of more detectors simultaneously or within an assigned time interval Contamination Radioactive Deposition of radioactive material in any place where it is not desired particularly where its presence may be harmful Control Menu The menu appearing on every application that runs in a window and on some non Windows applications Icons some dialog boxes and windows within an application workspace also have Control menus For applications running in a Window and for icons and dialog boxes Control menu commands move change the size of and close windows For non Windows applications the Control menu commands transfer information and perform other miscellaneous functions Also known as System menu Control Menu Box The icon that opens the Control menu for the window It is always at the left of the title bar Cosmic Rays High energy particulate and electromagnetic radiations which originate outside the earth s atmosphere Coulomb Unit of electrical charge in the practical system of units A quantity of electricity transferred by a current of one ampere in one second Coun
99. e 1 2068 4 00 T Pileup Reject Output Polarity Auto Low Hmh d k Negative Positive Only some of the supported MCA devices supply fully computer controllable amplifiers The ones that do provide a wide range of different capabilities Four different peak shaping types and up to eight dif ferent shaping time constants are supported for each device If you do not know the shaping time con stants your device supports you can enter any value into the field and the system will select the nearest available value 23 24 Quantum PRINCETON GAMMA TEGH coarse and fine gain controls combine to produce an overall amplifier gain Although in principle the actual gain is the product of these two numbers it is often the case that there are slight nonlineari ties For this reason we recommend using a coarse gain seiting that places the fine gain near the mid dle of its range so that fine adjustments in either direction do not require another change in the coarse gain Some amplifiers allow the user to control the pileup reject output independent of the pileup rejeci inputs of the ADC If pileup rejection is being used the output should be turned on and the polarity should be set to match the polarity of the ADC The inhibit polarity should be set to match the inhibit output from the preamplifier and the input polarity should match the output of the preamplifier
100. e fi 2 96 22 18 40 Report Activity of fp Start Time y pe ab Elapsed Counts PP Quantity g i Units The Status bar displays information about the primary spectrum whenever the cursor is within the spectrum display or the auxiliary spectrum display regions of the screen The cursor position controls the display of channel or energy information and counis f the cursor is within a region of interest ROI the ROI identification ROI integral ROI centroid and ROI FWHM are displayed The informa tion is updated in real time for live acquisitions Energy 86 35 Channel 686 Counts 7725 ROI BEGE DD Integral 3 042 Centroid 86 54 2 1 Main Toolbar The toolbar is located on the top of the screen right under the menu bar You can use the toolbar but tons to make immediate changes in the format of both the spectrum and the screen display and con trol spectrum acquisition Nuclide markers control Spectrum display control Acquire Stop Erase Redraw Vertical display controls Horizontal display Deconvolution trum lay m 2 m display controls controls Display p SAMMALIB MDB br 202 M ELT 61 46 Rate M266 cps ilve MOD 0040330000 Library Used Primary spectrum info 14 Quantum HPGT PRINCETON GAMMA TEGH Acquire Stop Acquire When the primary spectrum memory is connected to a live MCA device the toolbar includes an acquire button to start spectrum acqui sition During acquisition
101. e particular item it is applied to will also change in the graphic readout Click OK to apply the colors and quit the panel Cancel undoes the changes you made while Default Colors returns the display to the original PGT colors Click Save to save the selections to a CLR file This is useful if more than one operator uses the system or if you wish to have different color schemes for different applications or different printers In the Save dialog enter a file name and click Save Click Load to restore the selected colors Quantum Note Be sure you remember the color you have chosen for the primary spectrum If you forget just select Setup Select Display Color and check the graphic 65 66 Quantum WPGT PRINCETON GAMIMA TEGH 7 Analysis Tools The Analysis Tools menu includes the spectrum processing and analysis Cece aces functions Convolutions Channel Data B l Data ROI Detail Feak Search Peak Identity Analyze Rapid Scan Analyze with Deconvolution Analyze FOI Directed 7 1 Spectrum Calculator The Analysis Tools Spectrum Calc pro P Spectrum Calculator o o O gram is used to generate a new spectrum by a channel by channel calculation based on one or more other spectra This can be used ku to do simple strip operations or quite com plex calculations The calculator provides Spectrum Buffers four functions for add for subtract for sta divide and for multiply Press E
102. e this error will occur 3 Not implemented The function requested is not implemented the software ri 4 Wrong number of arguments vw An operation was attempted that required more or fewer arguments than the number supplied ri 5 Input out of range vw One or more of the arguments given was beyond the capabilities of the device or function Examples include attempting to read MCA channels beyond 2047 in a device with only 2k of memory or attempt ing to perform a peak search operation with a peak width of zero channels The software is designed to prevent inappropriate settings so you should not see this message if everything is operating normally 6 A non communications time out occurred sm An operation that should have completed did not complete in a reasonable period of time See also error 106 7 String was longer than allowed A function such as a file operation was given a string such as a file name that was longer than the software could accept Communication Errors 100 to 199 100 Stray characters were received Unexpected input characters were received during communication This might indicate a bad cable connection or might occur if the device has entered an unexpected state perhaps through manual intervention 101 Packet did not begin correctly A communication packet arrived without the header information required by the protocol This usually indicates a temporary communication error 122
103. e As Integer 0384 DevAddr As Integer 0386 DevUnit As Integer r 0388 DevID As Integer 0390 RESV0392 As Integer 0392 DevStatus As Integer 0394 hPORT As Integer 0396 hdev As Integer 0398 RESV0400 0 To 15 As Byte 0400 Energy Calibration Data EnCalFlag As Integer 10416 EnCalType As Integer 10418 RESV0420 As Long T04201 EnCal 0 To 3 As Single 0424 EnCalUnits 0 To 3 As Byte 10440 EnergyShift As Single 10444 RESV 448 0 To 15 Byte 0448 Shape Calibration Data ShCalFlag As Integer 10464 ShCalType As Integer 0466 RESV0468 As Long 0468 ShCal 0 To 3 As Single 0472 RESV0488 0 To 7 As Byte 0488 EfCalFlag As Integer 0496 EfCalType As Integer 10498 RESVO500 As Long 0500 EfCal 0 To 8 As Single 0504 EfCalUnc As Single 0540 RESV0544 0 To 47 As Byte 0544 Background Model Data BkgModelFlag As Integer 0592 BkgModelType As Integer 0594 RESVO596 As Long 0526 BkgModel 0 To 3 As Single 110600 RESVO616 0 To 7 As Byte 0616 Efficiency Calibration data PGT File Structure Presets are on if true Alignment Real Time Preset Live Time Preset Peak Preset Count Presets replaces Integ preset ROI which is to serve for preset ROI Preset Counts mode 1 ROIS REVx GHN 970224 Reserved for presets Hardware on which spectrum was taken Device name Numeric ID of Dev
104. e libraries and use them with different hardware or analysis configurations 4 4 1 Library Editor Features To edit a library choose Edit Library from the main menu to open the Nuclear Library Editor dialog box Nuclide Half life Information Select Nuclide Select Library Show in Nuclide List Consider Isotope in Peak Identify Routines Nuclear Library Editor ojx m su VARIDI SS S NN arka to E Show where use is True only m NUCID 13065 Nuclide Half Life 550 0 05 F USE Iv Radiati Energy Unc BetaEndPt Unc Intensity 00 00 True Use line in analysis Clear Isotope Efficiencies Select the library to edit from the Database to Edit submenu The dialog box contains lists of lines of each isotope you can select for inclusion in an analysis Each library contains a specialized set of data for example gamma libraries show only gamma radiation and alpha libraries show only alphas Select the nuclide from the Nuclide submenu You can then edit the radiations associated with the nuclide 38 Quantum HapGT PRINCETON GAMIMA TEGH To enable or disable the use of a particular line in the analysis routines left click on the line s Use field to select it and choose True or False from Ea the submenu To include a line in an analysis and in the Line List for Selected Isotope dialog box right the entry must be set to True re
105. e number of orbital electrons surrounding the nucleus of a neutral atom and according to present theory the number of protons in the nucleus Symbol Z Attenuation Factor A measure of the opacity of a layer of material for radiation traversing it the ratio of the incident intensity to the transmitted intensity t is equal to l where and I are the intensities of the incident and emergent radiation respectively In the usual sense of exponential absorption e the attenuation factor is e where x is the thickness of the material and m is the absorption coefficient Attenuation The process by which radiation is reduced in intensity when passing through some material It is the combination of absorption and scattering processes and leads to a decrease in flux density when projected through matter Background detector or system The number of counts measured in an instrument when no sample is present The background counts or count rate may be subtracted from the total or gross counts measured in a sample The gross counts minus the background counts equals the net counts from the sample only Backscattering The deflection of radiation by scattering processes through angles gt 90 with respect to the original direction of motion 126 Quantum PP GIT PRINCETON GAMIMA TEGH Beta Particle Charged particle emitted from the nucleus of an atom and having a mass and charge equal in magnitude to those of the electron Bra
106. e of the interpreted commands actually communicate using COM commands as well for example Wait Preset calls GetAcquire to check whether a preset has been reached Please keep in mind that these commands are case sensitive and are being interpreted by a program so they must be entered exactly as seen in order to work correctly Clicking the command button auto matically enters the command correctly but be careful if you are editing the script manually Command Acquisition Acquire Stop Acq Get Status Erase Presets Off On Set Real Set Live Elapsed Times Real Live Dead Time Spectrum Primary Save Set ID Copy Channels Get Name Get ID ROL Data StartAcquire StopAcquire GetAcgStatus EraseSpectrum PresetsOff PresetsOn SetRealPreset XXX SetLivePreset XXX StoreDT DT txt SetPrimary 1 SaveSpectrum X SetSpectrumlDXX CopySpec 2 1 GetNumberCounts GetName GetID GetROlData 3 NET Turn on acquire for the device in the selected memory Turn off acquire Reports the status of the acquisition in the message line Erase the selected memory Turn off all presets for the selected device Turn on any presets for the selected device that have values entered Prompts user for desired preset seconds XXX Prompts user for desired preset seconds XXX Reports the elapsed real time in the message line at the top Reports the elapsed real time in the message line at the top Prompts user for file n
107. e scrolling report window PGT devices report model firmware version and serial number of the device Other devices may only provide a subset of this information When the search is complete exit the program Quantum Note If you have no hardware you must still run the hardware search software Click Update without selecting any devices to scan The system will not find any hardware but it will generate the configuration necessary for the MCA to operate 1 5 Starting the Software Double click on the Quantum icon to start the software program When the software starts it reads the configuration generated by the hardware search program One of the internal memories of the soft ware will be assigned to each device in the configuration If more devices are present in the configura tion than the number of available memories in the software the first devices will be assigned to all the memories and any remaining devices will be inaccessible If during initialization one of the devices does not respond an error message left will be displayed Make sure the ref Device found in HAS 2000 Not A di Devi IN Device found in Huds GUN Not Responding to Open Device erenced device is turned on and properly connected to the Retry system After you have corrected the problem click Yes to retry On some systems this error message will display the first time you run the software after rebooting the machine because the system does
108. e software attempts to extract as much information as possible from the files When Load to Buffer is used all setup parameters and ROls are also loaded The ROI details are recalculated once the file is loaded The library and informa tion on whether its efficiencies were used in analyzing the spectrum is also loaded from the spectrum header The loaded spectrum is placed into an unused static memory which then becomes a static memory Quantum currently supports the following file types for loading ANS Princeton Gamma Tech and American Nuclear Systems native file format Version 0 1 2 3 OXS Oxford Instruments file format SPT PGT IMIX and Oxford Instruments PCA format and Gamma Trak SPM Oxford Instruments older PCA format MCA Canberra S100 file format SPC Ortec System 5000 file format MAS Microbeam Analysis Society Version 1 1 30 Quantum HPGT PRINCETON GAMIMA TEGH 3 2 Load Spectrum Options Choose File Load to Buffer to place the data into the first empty static memory buffer The spectrum is always designated as Static To replace a spectrum select it as the primary spectrum and select File Load Spectrum Data Only You can also use File Load to Buffer to load a spectrum into a primary memory that is currently con nected to a piece of hardware a Live memory The device type must be the same as that of the stored spectrum file and the device must support enough ADC channels to load the data If you select
109. ect the coarse gain usually the lowest value to start Click the Acquire go button Stop and restart acquisition as you adjust the coarse and fine gains 4 When the peaks in the source are near their expected channels switch to the ADC2 tab to adjust the Upper and Lower Level Discriminators ULD and LLD as needed to reduce noise and dead time 5 Goonto a linear and quadratic energy calibration 9 11 1 Manual Two Point Calibration Section 6 3 1 page 52 Manual calibration requires that you collect the spectrum of a known source standard first 1 Choose the first peak for the calibration Press the right mouse at the left of the peak and drag to expand the spectrum enough to let you see the center of the peak clearly 2 Select Setup Manual Calibrate Two Point Energy Follow the directions in the pop up as follows Click the left mouse button once at the center of the selected peak That position will be entered into the POPP and the Enter Energy Select Second Point with Mouse cursor will flash in the Energy box Enter the correct energy for that nuclide me Move change the spectrum display range as needed until you see the second peak you wish to use Click the left mouse but ton at the center of that peak Enter the correct energy for that nuclide line Press OK Two Point Calibration This procedure does a simple linear energy calibration For accurate work follow this with the ROI
110. ector This information is combined with the detector type to determine whether the voltage will be fixed or variable over some range The system will only vary the bias voltage applied to scintillation detectors or gas flow detectors For HPGe and Si Li detectors set the optimum and maximum voltages very close together PGT Setup Menu PRINCETON GAMMA TECH To delete a detector from the database select the detector from the Detector Designation drop down list and click Delete To create a new detector click New and then fill in all of the information If you edit any information click Save to store the updated data in the detector database If you want to store the currently displayed detector information in the header of the primary spectrum click Apply This will invalidate any calibration curve computed using the Auto Calibrate Efficiency Calibration see Effi ciency Calibration on page 49 and you must re calculate the equation from the stored efficiency data Quantum Note Good detector parameters are essential for accurate results in Quantum MCA Gold and improve performance in Quantum MCA 6 5 Clearing Calibrations Setup Clear Calibrations clears ALL calibrations energy resolution and efficiency associated with a memory 6 6 Tool Setup The Tool Setup dialog box contains commands that allow you to set system parameters that affect the operation of many of Quantum s mathematical search and analysis tools You
111. ed at the bottom of the list 88 Quantum WPGT PRINCETON GAMIMA TEGH 9 13 System Calibration Manual Resolution Detector resolution calibration is highly recommended The software uses resolution information to match peaks to library lines In the Tool Setup dialog box the Energy Window for Line Matching selections also make use of the resolution Section 6 3 3 1 You may use the spectrum from the Energy by ROI Centroids calibration Select Setup page 54 Manual Calibrate Resolution Calibration The list of ROls in the spectrum opens gi Detector Resolution Calibration Centroid Include FWHH ker calc Chick Include to Select Current Peak RUI R Cl p Previous Next uzu Execute 2 To select a line to be used in the calculation click on it in the list and press Include Click on the next line of interest or click the Previous or Next buttons and again click Include If you change your mind click on the enabled line to select it again and press Remove 3 After all the lines have been entered select either Linear or Quadratic recommended Then click Execute PPGT Procedures 89 PRINCETON GAMMA TECH 9 14 Qualitative Analysis Peak Search and Identify Qualitative analysis is the basic function of Quantum MCA and the necessary first step in quantitative analysis 9 14 1 1 Peak Search After the system has been properly calibrated for both energy and resolution collect the spec tr
112. ed isotope File Print Ordered by Nuclide and File Print Ordered by Energy produce a complete list of all nuclides and radiations ordered either by nuclide or by radiation energy If the Show where use is True only box is selected just those enabled isotopes are included Data Clear All Efficiency Data erases all efficiencies in the database This is useful when you have cloned a library for use with a different hardware configuration 40 Quantum WPGT PRINCETON GAMIMA TEGH 5 View Menu Options The View menu includes options that affect the display of various types of information Display Offsets setups v ROI Toolbar 5 1 Display Offsets Choose View Display Offsets to open the Spectrum Display Offset dialog box Ea Spectrum Display Offset Percent Offset CLEAR ALL This dialog box contains commands allowing you to offset the vertical display for each spectrum The offset affects the display only and does not affect the data itself This function is useful when you want to view similar spectra in overlay mode as shown in the example below 1 H l K F r ly 4 Lindel atl SL Ree eae ee PA d gra pa H R Fo Vs dd pr a AA art A halal e Click the up and down arrows corresponding to the spectrum of interest to increase or decrease the offset by one unit at a time e Click Clear to reset an offset back to zero PPG
113. een as well as vertical scaling will be associated with the primary spec trum You cannot free a primary spectrum memory Prompt gamma The gamma ray emitted in association with a neutron capture in a target nucleus These gamma rays are coincident in time with the neutron capture and are typically higher energy several MeV than decay gamma rays Proton Elementary nuclear particle with a positive electric charge equal numerically to the charge of the electron and with a mass of 1 007277 mass units Quadratic Compression Conversion QCC Ultra fast pulse processing technique that automati cally corrects for the variations in peak widths as a function of energy in Nal detectors Reaction Nuclear An induced nuclear disintegration that is a process occurring when a nucleus comes into contact with a photon an elementary particle or another nucleus In many cases the reac tion can be represented by the symbolic equation X a Y bor in abbreviated form X a b Y in which X is the target nucleus a is the incident particle or photon b is an emitted particle or photon and Y is the product nucleus Resolution The ability of a detector system to discriminate between peaks spectral lines close to one another in energy the narrower the peaks the better the resolution FWHM Full Width at Half Maximum is a measure of resolution PPGT Glossary 131 PRINCETON GAMMA TECH Restore Button The small box containing a Down arrow and
114. ell Time Note that if you select MCS PHA mode the following features are disabled enabled e Markers e ROI FWHM e ROI centroid e Library ELT e Dead time e Rate e All peak search and identify analysis menu options If PHA is restored after MCS then the previous Energy calibration is restored 28 Quantum PGT PRINCETON GAMIMA TEGH Various MCAs implement their MCS modes in different ways Some of the MCAs supported by Quantum the PCA 3 and PCA Multiport only count evenis from an external signal input Others only support counting pulses within the SCA region between the lower and upper discriminator levels Others allow still other sorts of inputs such as input count rate or an internal reference The Dwell Time the amount of time for which data will be acquired in each channel must be set using the Pre sets tab while in the Hardware Controls screen mode The PCA3 and PCA Multiport only support a predetermined set of values for the dwell time The supported values can be found in the respective MCA hardware manuals In the software you can enter any value When the dwell time entry control loses focus the value you have entered will be reset to the nearest value supported by the hardware f an MCA device supports multiple passes enter the number of passes in the MCS Passes box Con sult your hardware manual to determine the input types and dwell times available and the maximum number of passes that can be performed PPGT Fi
115. er the background to compute net counts or centroids The background ROI can be user defined or created automatically based on the settings in this dialog box In QuantumGold the system can also store an ambient background spectrum for each memory This spectrum will be normalized and subtracted from the spectrum being analyzed If both Continuum BKG Correction and Ambient BKG Correction are selected the latter will be performed first followed by the continuum correction Select the appropriate check box to enable either correction Spectroscopy Type The commands in the Spectroscopy Type panel are used to make default decisions about issues such as the full scale energy This is particularly important when using the Cs137 Coarse Adjust feature Spectroscopy Type amp Gamma Beta Alpha 6 6 2 Choosing Sensitivity and Limits Settings to Optimize Results The values you choose for the peak search mode overlapped vs low peak to background the sensi tivity parameters integral and power and the limits parameters particularly the uncertainty limit can make a big difference in the number of peaks found in a spectrum If you set the numbers very small you may find hundreds of peaks in a spectrum Since you are limited to a maximum of 250 ROls the system may run out of ROls finding peaks at low energies and fail to mark anything at high energies If the val ues are set too large the system will only find very large peaks and miss sma
116. eset and restart the acquisition Note that changes between count type presets are not possible during a single spectrum acquisition and it is not recom mended that you use more than one type of preset at a time The count presets panel presents different options depending on the type of count preset selected When a selected ROI is required an additional panel opens to select an ROI The statistical presets should be entered in terms of minimum confidence in percent while the other presets are all in terms of integral numbers of counts To turn off either the counts preset or the time preset without turning off the other change the appro priate field to O or to a very large number This panel also provides an opportunity to set the dwell time for MCS operation when MCS mode is selected See the next section for details VFapiGT Main Display 27 PRINCETON GAMIMA TEGH Note Not all MCAs behave the same with respect to presets The software attempts to make all MCAs look the same by making the device stop counting when the elapsed time equals the preset time However some MCAs add a newly set preset to the existing elapsed time creating a situation where the device does not stop when the total elapsed time equals the preset time With these devices the actual preset may be the sum of the current elapsed time and the newly entered preset 2 3 Multi channel Scaling Mode MCS Quantum supports the MCS multi channel scaling data acq
117. eue AHENuenb sej PSJSAAIOH JO UeOSpidey Hoddns sis jeue AHEN uenb OU SI 9J9U H SIU 1S nb l Aluo Hod H Am u pi yeed HOd H yoeas yead ed pie d DulL MeE d od juodaH SIS IEUV p p lOH SISAIEUV ueos pidey YE ci 5 1 80 pidey uau sis jeue AHEMNuEnb sey HEMHOS yI PISO Ueospidey u Du 4 od Jsis jeuy uunno ds Asewud o jdde pue dnjas joo UI xoqyo y S rou tolH Aeq OS 94 119 sy 9 uunn ds Ayewiid o Adde pue dnjas joo ul xoqyo y S rou l l eqq asn v yo uouf Suus sy H4arT sn e ro sn o Meqi YOIUM 12 l S BuuIS sv uunsjoeds Mew ud SU UM paeyeloosse Meqi y JO y 190 d 1 p ll ds aul JO yod poonpoJd Ise y 1404 BuuIS sv uunno ds Areulud Su uo siskyeue Bus SY 100 QuantumMCA QuantumGold pb nunuo e lul WOS winjuenH 201 4 101 QScript T PRINCETON GAMMA TECH P peels uonisinhoe wnioads Arewud y YIIUM ye ewo SAMODUHAA UI SWI OU UO SI 1ndul HO SI Indu 9 Ul Jou SI UXlUM UEH JO 11 Indu Al 10U SI 5 Mewnd 10N MO puewwo y O puods 1 1ou pip
118. g does not initiate an action After selecting an item you choose the action you want to affect the item See also choose and highlighted Selection Cursor The marking device that shows where you are in a window menu or dialog box The selection cursor can appear as a highlight or as a dotted rectangle around the text in a dialog box option Self Absorption Absorption of radiation emitted by radioactive atoms by the material in which the atoms are located in particular the absorption of radiation within a sample being assayed Singlet An gamma ray photopeak that is free of spectral interferences Specific Activity Total activity of a given nuclide per gram of a compound element or radioactive nuclide Standard Radioactive A sample of radioactive material usually with a long half life in which the number and type of radioactive atoms at a definite reference date and time is known It is used as a radiation source for calibrating radiation measurement equipment Static Memory Buffer Designates a memory which has had a spectrum loaded from disc It cannot be used for data acquisition None of the setup parameters associated with this memory can be changed Sum Peak A peak at an energy that corresponds to the sum of two or more other peaks energies The term sum peak is usually restricted to true coincidence summing also called cascade summing A sum peak may also occur from random summing at high count rates because the ind
119. gOff As Integer 0258 ADCGSMode As Integer 0260 ADCGSROIStart As Integer 0262 ADCGSROIEnd As Integer 0264 ADCGSROI As Integer 0266 ADCGSOffset As Single 0268 ADCGSTau As Single 0272 ADCGSRange As Single 10276 ADCZSMode As Integer 0280 ADCZSROIEnd As Integer 10284 ADCZSROI As Integer 10296 ADCZSOffset As Single d ADCZSTau As Single 0292 ADCZSRange As Single 0296 ADCDwlSmpTime As Single 10300 ADCPasses As Long 10304 RESV0308 0 To 27 As Byte 103061 HPG T PRINCETON GAMIMA TEGH Coarse Gain Fine Gain Pole Zero Shaping time constant in microseconds Fast threshold setting 100 to 100 REV1 formerly AmpType 0 Bipolar Gaussian 1 Unipolar Gaussian REV2 2 Gated Integrator 3 Triangular REV2 Bitwise control word xxxx xBUF PxI paRr B BLR rate high U BLR user adjusted F fast disc user adjusted P pos ext inhib pol I ext inhib on positive input pol p ext preamp a ext amp R pos reject r reject on Preamp type 0 TrReset PulOpt 0 other Reserved for amp info Operating Mode O PHA 1 MCS 2 SVAH 3 SVAL ADC control word 0000 0000 PUL SOER P pos peak det U place pulses over ULD in last chan L pos LGO S ext sync r reject input on R pos reject in pol Gate Mode 0000 0000 0000 OEMM MM off 1 anticoin 2 coin E 0 level triggered 1 edge trig Dead
120. gle enter zero In the Detector Type panel select the appropriate type of detector This is very important since many of the subroutines depend on this information for selecting mass absorption coefficients and other crit ical parameters For Si Li and HPGe detectors also set the dead layer thickness in this panel Dead layer information should be available from your detector manufacturer In addition the default resolution model used for the detector when a Resolution Calibration is NOT available depends on the detector type as follows For Nal detectors a square root versus energy relationship is used for resolution with a res olution of approximately 8 FWHM at 661 keV DetRes 53 0 Sart energy 661 66 For HPGe detectors a linear model for resolution versus energy is assumed with a resolu tion at 1332 keV of 2 075 keV DetRes 0 6097 0 0011 energy e For SiD detectors used in alpha spectroscopy a 70 keV fixed peak width is used Por Si Li X ray detectors the following equation is used which gives a resolution of 140 eV at 5 89 keV DetRes Sart 19600 2500 energy 5 894 1000 For Gas Flow Proportional detectors the following equation attributable to Charles and Cooke 1968 is used DetRes 12 Sart E If a Resolution Calibration has been done it replaces these assumptions The last two parameters tell the system particularly the Auto Calibrate modes the optimum and max imum bias voltages for the det
121. he software Various conventions are discussed below Section 2 describes more of the controls and features available in the software 1 8 1 Data Entry Controls Single pieces of data are displayed by the software in recessed 3D controls If the background of the control is gray then the data is read only and cannot be edited If the background is white then the data can be edited If the data is associated with a parameter in the hardware when the data entry control loses focus if you press TAB or select another control with the mouse the data will be written to the hardware and immediately read back The value read back will then be displayed in the screen control This allows you to type in arbitrary values which are converted to the hardware s nearest acceptable values and then displayed for your information Introduction PRINCETON GAMIMA TEGH 1 8 2 Left Mouse Button You can use the left mouse button in the following ways To paint ROls e Press CTRL press the left mouse button in the primary spectrum and drag to define the region of interest ROI For more information on setting ROIs see Section 9 4 To select a spectrum or ROL e Display the spectra in tiled mode e Left click in the tile of the desired spectrum to make it the primary spectrum t will change to the primary spectrum color white in the PGT default colors Note To select an ROI for editing simply click on it to make it the current one
122. iated with an excited state of a nucleus usually following an alpha or beta decay beta minus positron emission and electron capture or resulting from fission produc tion of a neutron enriched nuclide Decay Constant The fraction of the number of atoms of a radioactive nuclide which decay in unit time see disintegration constant Decay Radioactive Disintegration of the nucleus of an unstable nuclide by the spontaneous emis sion of charged particles and or photons Default Button The command button in some dialog boxes selected as the most logical or safest choice This button has a bold border when the dialog box appears and pressing ENTER chooses the button Detector Radiation An instrument used to determine the presence of and sometimes the amount of radiation Dialog Window A rectangular box that either requests or provides information Many dialog windows present options to choose among before Windows can carry out a command Some dialog windows present warnings or explain why a command cannot be completed Directory A collection of files and subdirectories that are stored at the same location on a disk The name of the directory identifies its location Part of the structure for organizing your files on a disk See also subdirectory Discriminator An electronic circuit that outputs a logic pulse if the amplitude of the input pulse exceeds some assigned threshold Disintegration Constant The fraction of the number
123. ice Type 1 PCAP 2 PCAM 5 PCA3 Bus address of device Unit number 0 7 for P amp 3 IEEE addr 1 16 Pointer record in SPECD PRM Formerly device capabilities Device Status Port handle not valid from one session to another Device handle not valid from one session to another Reserved for device info Flag for valid energy calibration Type of energy calibration 0 linear 1 sgrt Formerly EnCalKey pointer to calibration data in data base Calibration constants X axis calibration units Amount this spectrum is shifted from the nominal energy calibration Reserved for energy calibration Flag for valid shape calibration Type of equation represented Formerly ShCalKey pointer to calibration data in data base Calibration constants Reserved for shape calibration Flag for valid efficiency calibration Type of equation represented Formerly EfCalKey pointer to calibration data in data base Calibration constants Calibration uncertainty Reserved for efficiency and other calibrations Flag for valid background model Type of equation represented Formerly BkgModelKey pointer to calibration data in database Calibration constants Reserved for background model 117 118 Quantum Detector DETType As Integer 10624 DetShape As Integer 0626 DetID 0 To 11 As Byte 106281 DetThickness As Single 106401 DetDiameter As Single 10644 DetWellDia As Single 0648 DetWellDepth As Single
124. ies of peaks in the spectrum to line energies from the radiations database A line and a peak are considered to match in F 4 P HM A B x Energy energy based on the Energy Window defined by the A and B parameters A 050 B 0 000 Energy Window for Line Matching Two approaches are available When A x FWHM is selected the energy window is based on the predicted resolution at the energy of the peak This mode is used with germanium detectors A good starting value for A is 2 5 When A B x Energy is selected the energy window is based on a simple linear equation This is the usual setting for Nal detectors in either linear or QCC mode Good default values for A and B in this mode are 8 0 and 0 05 respectively 60 Quantum H pGT PRINCETON GAMIMA TEGH The values given above are rather tolerant You may wish to decrease them as your system is tuned to optimal conditions You can see the value actually used for a peak by looking at the ROI Detail report You can observe the effects of the different approaches and of different values for A and B in the left hand peak of the graphic in the Tools Setup dialog box Library Efficiencies Use Library Efficiencies allows you to use the isotope efficiencies previously calculated and stored in the current library If you do not check this item the efficiencies will be recalculated FWHM Energy window for Peak width line matching Background gap Background ROI ROI Width a
125. ine Energy Cal Resolution Cal System Quadratic Energy Calibration using 152 H 13 Lines uf 13 matched in standard E Efficiency Cal Chan Net Counts Standard H B 26554 60 43 8 39 522 H B 26554 60 44 118 H B 26554 60 41 618 H B 45 400 1H7 1 121 783 162 6 244 699 196 3 344 281 303 3 vee 903 338 9 964 1351 363 5 1085 914 1188 335 1112 116 1468 611 If not enough lines match or there are too many extra lines you may see a warning in the report to adjust the sensitivity setting in the Tool Setup dialog box To open the Tools Setup dialog box without leaving the System Auto Calibrate dialog box choose Setup Tools Setup To reduce the sensitivity increase the Integral or Power value To save the report select File Save Report as Text File from the main menu in the System Auto Cal ibrate dialog box To print the report to the default printer choose File Print Report 6 2 5 Resolution Calibration Resolution is a measure of the ability of a detector system to discriminate between peaks The Full Width at Half Maximum FWHM is a typical unit of measure Run resolution calibration after running energy calibration to compute the resolution of the detector as a function of energy Resolution calibration can be done with any multi line standard containing five or more lines You should run the resolution calibration to replace the default values which are based on a very simplistic linear model of the detector 48 Q
126. ines in the nuclide database are enabled for each nuclide you have included PPGT Analysis Algorithms 111 PRINCETON GAMMA TECH Now select ROI Directed from the Tools menu When this approach is used the following calculations are performed 1 The smoothed background spectrum is subtracted channel by channel from the data ROlupdate is run to get a complete set of values for the QROI structures For each ROI the associated nuclide s radiations are searched for any enabled lines which fall within the ROI The intensities of these lines are summed and a weighted average efficiency is calculated The activity for each line is calculated according to the following equations The total activity for the sample is calculated as described below 100N 8 FIL Here 5 is the summing cortecuun mor we nuclear database Generally it will be 1 00 unless set by the user to another value Activity where the units are Bq p 100 271 465 JB MDA FYT The A represent the activities calculated for each ROI in the spectrum which has been identified as belonging to an isotope in the search list Since an isotope can have more than one ROI asso ciated with it we calculate the activity of each isotope as the weighted average activity of the ROIs found for the isotope Therefore Weight W A o LWA 47 1 Isotopic Activity i Uncertainty 112 Quantum EPGT PRINCETON GAMMA TECH This page intentionally blank P
127. ing a Down arrow at the right of the title bar Mouse users can click the Minimize button to shrink a window to an icon Other users can use the Minimize command on the Control menu Multiplet A spectral feature containing more than one photopeak within an energy region of the spec trum Each component of the multiplet add counts to the other peaks background The multiplet must be mathematically separated deconvolved to extract meaningful information about each peak 130 Quantum PP GIT PRINCETON GAMIMA TEGH Neutrino A neutral particle of very small rest mass postulated to account for the continuous distribu tion of energy among the particles in the beta decay process and to allow for conservation of momen tum in beta decay Neutron Elementary nuclear particle with a mass approximately the same as that of a hydrogen atom and electrically neutral its mass is 1 008982 mass units Neutrons are commonly divided into sub classifications according to their energies as follows thermal around 0 025 eV epithermal 0 1 eV to 100 eV slow lt 100 eV intermediate 102 to 10 eV fast gt 0 1 MeV Nucleon Common name for a constituent particle of the nucleus applied to protons and neutrons but will include any other particle found to exist in the nucleus Nucleus Nuclear That part of an atom in which the total positive electric charge and most of the mass are concentrated Nuclide A species of atom characterized by the const
128. intRprtProgram SaveRprtProgram XX Opens File selection panel to load an MCA configuration file Opens File selection panel to load an ROI file Sets number of loops X between LoopBeg and LoopEnd Use early in script file if number is zero program will request number of loops at run time Place holder in file for LoopEnd to loop back to Will cause file rewind back to LoopBeg for DoNumPass times Runs the Peak Identify program Saves spectra inside a loop using specified prefix concate nated with the loop number as the file name e g SPEC23 ANS limited to 4 character prefix Wait at this point for MCA preset to be reached Prompts for input of wait interval in XX seconds Prompts for external device selection and value waits for selected digital input to change to the selected value Prompts for Message to be displayed Start external program e g AutoLoad and do not wait for it to complete Start external program and wait for it to complete Selects which library to use for analysis Get library from the primary spectrum and get Use Library Efficiencies setting from the Tool Setup Select analysis program Use analysis method selected in text box above Print results of last analysis Prompts for file name and saves results of last analysis in file When checked sets the Use Library Efficiencies for the selected library m SetExtOut 1 1 Sets logic output This example sets output number 1 to True Opens a
129. ion Check your inputs to see if they make sense DLL specific errors 300 to 399 300 Current device does not support function If the current hardware device does not have a particular feature you may see this error For example if an attempt was made to set the amplifier gain on a device with no amplifier this would be the result ing error However the software is designed to display only the controls that are supported by the device so this usually indicates a software bug 301 Ran out of a DLL limited resource Some of the DLLs dynamic link libraries provided with the software support only limited numbers of certain objects such as device handles If the software attempts to use more of these than are avail able this is the error message you will see 302 Windows device driver returned an error This is the error for the general case of a failure while accessing a standard Windows device driver 303 Selecting a device failed general Selecting a hardware device as primary failed but no specific reason such as a communication error is known 320 File not found You tried to open a file that does not exist Check the filename and verify that the extension was the one you intended 321 Couldn t read desired data from file The file was truncated corrupted or otherwise unreadable Make sure that the file type was correct or that the correct file was selected This could also result from a disk error but the
130. is 71 quantitative analysis 72 ROl directed 74 with deconvolution 73 save 31 6 setup 41 supported formats 29 spectrum display expand range 17 grid 16 of set 40 tile overlay 15 tool bar controls 13 spectrum display control 6 State iv status bar 13 system auto calibrate 42 system configuration 22 system parameters 36 system setups 41 T tiled display 12 tool setup background correction 62 energy window 59 integral 59 low energy cutoff 59 MDL parameters 62 optimization 62 peak finding mode 58 power 59 statistical uncertainty 59 U user interface 8 mouse button usage 9
131. is way 1 7 2 Spectrum Data Readout When the system is in overlaid display mode all of the selected specira are displayed in the same win dow If there is no data in the primary spectrum for example when the primary spectrum is connected to an MCA device that has not acquired any data but there is data in another memory for example you loaded a spectrum for viewing it is easy to forget which spectrum is the primary one You may think the system is broken when the cursor fails to read out the data from the spectrum you can see m lt is important to remember that the primary spectrum is always displayed in the I primary spectrum color white in the PGT default colors Its reference is dis played at the top of the screen When you click the Spectrum Display Control button left the Spectrum Display and Memory Control dialog box will open with a list of all spectra including the primary spectrum currently being dis played Click the Tile Overlay button left to display all valid spectra in tile mode Click on the spectrum of interest to make it primary See Display Control Buttons on page 15 for a complete description of the display control buttons 1 8 User Interface Conventions This section describes the keyboard and mouse controls Every effort has been made to generate a consistent user interface throughout the software Understanding the conventions used can ease your becoming proficient in the use of t
132. itution of its nucleus The nuclear constitution is specified by the number of protons Z number of neutrons N and energy content or alternatively by the atomic number Z mass number A N Z and atomic mass To be regarded as a distinct nuclide the atom must be capable of existing for a measurable time thus nuclear isomers are sepa rate nuclides whereas promptly decaying excited nuclear states are unstable intermediates in nuclear reactions are not so considered Overlaid Mode In the overlaid mode all of the spectra are displayed using the full spectrum display window Each spectrum is displayed in a separate color If more than one spectrum is being displayed then all ROIs are displayed as red In the single spectrum case each type ROI is displayed as a differ ent color Positron Particle equal in mass to the electron and having an equal but opposite charge Power Stopping A measure of the effect of a substance upon the kinetic energy of a charged parti cle passing through it Presets Control A data panel providing access to the hardware presets available for controlling the acquisition of a spectrum Primary Spectrum A primary spectrum is one that is currently selected from either the memory buffer control panel or by clicking in its tiled display window Only one spectrum at time may be designated as primary although more than one spectrum may be concurrently displayed The data panel at the bot tom of the QUANTUM MCA scr
133. ividual events occur within a time period that is less than the peak pair resolving time of the amplifier Regardless of whether the summing is the result of nuclear or electronic effects the effect is to lose one count from each peak summing and to add one count to the sum peak A sum peak differs from a crossover tran sition in that a sum peak would not be present if the count rate were low enough and the sample were far from the detector Pair peak is a synonym for sum peak Swap File An area of your hard disk that is set aside for exclusive use by Windows in 386 enhanced mode This area is used only when your system runs low on memory Text Box A box within a dialog box where you type information needed to carry out the chosen com mand The text box may be blank when the dialog box appears or may contain text 132 Quantum PP GIT PRINCETON GAMIMA TEGH Text File A file containing only letters digits and symbols A text file usually consists of characters coded from the ASCII character set Tile A way of arranging open windows on the desktop so that no windows overlap but all windows are visible Each window takes up a portion of the screen Tiled Mode In the tiled mode the display window is divided into horizontal bands with one spectra dis played in each band All ROls are displayed as red In tiled mode the user can click with the left mouse button in one of the spectrum bands to make that spectrum the primary spectrum This fu
134. l Resolution 88 9 14 Qualitative Analysis Peak Search and Identify 89 9 14 1 PeakSearch 89 9 14 2 Peak dentify 89 9 15 Quantitative Analysis Rapid Scan 90 9 16 Quantitative Analysis with Deconvolution 90 9 17 Quantitative Analysis ROI Directed 91 10 QScript 93 Appendix A Analysis Algorithms 103 A 1 Numerical Computation Routines Propagation of Errors 103 A 2 ROI Data Calculations 104 Pao Peak FINOS separa Land ro eee da PA RA eae bee eee FY eee nd 108 A 4 Peak Identification 109 A 5 Quantitative Analysis Algorithms 109 A 5 1 Analyze Rapid Scan 109 A 5 2 Analyze ROI Directed 110 Appendix B Detector Efficiency Model 113 B 1 Common Parameters for ALL Detector TypeS 113 B 2 Nal and Germanium Detectors 114 Appendix C PGT File Structure 115 C 1 PGT Spectrum Header 115 C 2 Spectrum Data
135. lculated E E E n 0000 000 Include All Execute e Click on each line you want to include in the calculation and then click Include The Include button will change to Remove to allow you to remove an included line After you have selected all the lines click Execute Close the Detector Efficiency dialog box The results of the calibration are displayed in the System Auto Calibrate dialog box The display graphs the fit equation and the model efficiency equation The report lists the equation with its constants and other detector parameters These values are also included with the spectrum header i System Auto Calibrate File Setup Eff Cal Calibration Standard MGS1073 gt Status Elapsed Real Time Elapsed Live Time Peak Counts Cs137 Coarse adjust Fine Energy Cal Resolution Cal System Efficiency Calibration 11 Lines of 12 matched in standard NGS1673 Nuc lide Std Activity Decay Corrected i Cuci Hn5 4 m 49 E 603 Cob 5 48 2 155 n B2 E 602 Shi2s 5 95 2 Energy Efficiency Standard Het Int EFF Curve Nuc lide 86 54 8 123 17 748 617 Fuihh 599 1 i 155 886 a a 5125 52 Quantum EPGIT PRINCETON GAMIMA TEGH 6 3 Manual Calibration Quantum includes a manual calibration option To perform a manual calibration Place an appropriate source such as Cs137 in the usual operating position for your detec
136. ld indicate that the device is no longer online or that it has been reset in such a way that it can no longer identify when it is supposed to respond In the latter case you may need to re run the hardware search procedure HPG T VVarning and Error Codes 123 PRINCETON BAMIMA TEE 113 Response was invalid The response received for the current command was ill formed or outside of the valid range Although this might occur infrequently due to communication errors if you find it occurring frequently it probably indicates a software bug that should be reported 114 Timeout inside body of message Part of a message was received but the rest never arrived This could indicate a faulty cable or the equivalent Math Errors 200 to 299 200 Attempt to divide by zero S An operation needed to perform a division and the divisor was zero 201 Couldn t solve for discontinuities The input equations contained discontinuities that made their solution differentiation etc impossible 202 Result was an inexact approximation This indicates either an excessive accumulation of rounding errors or an attempt to solve a set of equations without enough input information 203 No parameters were variable An attempt was made to perform a fitting operation when all of the fitting parameters were fixed 204 Matrix was singular unsolvable A mathematical operation such as a matrix inversion was attempted for a set of inputs that had no solut
137. le Menu 29 PRINCETON GAMMA TECH 3 File Menu The file menu displays all the common file access functions of the program 3 1 Spectrum File Types Use the File Load commands to load many different file ls ypes Load Spectrum Data Only Import User The new feature for importing non PGT spectrum files is E ave Ligplay As Metafile implemented with a separate program QtmConvert exe The Load System Configuration program s source code is included for users who wish to add Bore Ge other file conversions The code contains comments outlining TERRE the steps required to implement new file conversions View Background Clear Background You can select the various supported file formats in the Load 5 Merge F ls to Buffer dialog box from the Files of Type submenu By Save As Rls default spectra are stored in the spectra directory created Print Spectrum during installation see Directory and Path on page 2 for alist ie ae and ROls Setu of directories in Quantum If you create or select a new folder it will become the new default You can select any drive or ER directory using the commands n the Load to Buffer dialog C Program Files PGT 2 Quantumspectra h aMGS1073 4N5 box C Program Files PGT Quantum specta Mad DT ANS C Program Files PGT 2G uantumspectraN ap ANS The native file type for PGT Quantum software is ANS When other file types are loaded th
138. lifier e ADC controls ADC ADC2 e Stabilizers External controls Presets The large number of ADC controls are distributed across two tabs The first is for the digital interface controls and the second is for more traditional spectrum controls PreAmp Bias and Amplifier are used almost exclusively to set up the system the very first time it is used After initial setup these tabs are seldom needed The Presets tab allovvs access to many spe cial preset modes These can be useful for special projecis but are usually not needed for general analysis vvork Once you have established a configuration that works well with your device it is strongly recom mended that you save this configuration by selecting File Save System Configuration You may even vvish to keep a copy of the small file this creates on a separate floppy since it contains all the important hardvvare and analysis setup information This file can be useful in several different vvays f you use the software in different configurations such as different time constant settings or gain values you can easily switch between them by loading a saved MCA configuration Make sure you assign each one a descriptive name so you can tell them apart f you upgrade your software in the future or need to reinstall it you can use the saved copy to easily restore all the configuration information e If your computer crashes or is accidentally rebooted without saving the necessar
139. light They are usually produced by bombarding a metallic target with fast electrons in a high vacuum In nuclear reactions it is customary to refer to photons originating in the nucleus as gamma rays and those originating in the extranuclear part of the atom as X rays PRINCETON GAMMA TECH A acquire data 80 acquisition setup 6 analyze with deconvolution 73 auto calibrate 42 coarse adjust 81 coarse adjustment 45 detector efficiency curve 84 efficiency 49 83 fine energy 46 82 resolution 47 82 auxiliary display 12 B background spectrum ambient 32 bias supply enable 23 C calibration 86 setup 43 calibration standard edit 44 85 channel data 68 channels number of 24 configurations save 32 convolution filters spectrum filters 67 D deconvolution display 14 detector efficiency 84 detector model 55 113 detector parameters 55 directories default 2 E efficiency calibration 49 83 energy range selection 42 error messages 121 ethernet 4 F FWHM full width at half maximum 60 H hardware controls 22 ADCs 24 Index 133 Index alarms 23 amplifiers 23 channels 24 conversion mode 24 external controls 26 preseis 26 stabilizers 25 hardware recommendations 1 hardware search 2 help menu 75 installation 2 isotope efficiency 38 isotope line list 20 isotope markers 18 option menu 19 K keyboard shortcuts 10 L library select 18 limits 59 line summary 71 M manual calibr
140. ller peaks pGT Setup Menu PRINCETON GAMIMA TEGH Both of these values are strongly dependent on the ROI width count time and count rate Use the fol lowing approach to effectively select the sensitivity parameter values Start with the values set low so you do not miss peaks on a first pass at peak search 1 As an example for a one minute count time on a 1 microcurie source directly on the detector endcap try the following initial settings Nal spectra 1250 Si Li spectra 1024 Table 6 4 Sensitivity Parameters Set the low energy cutoff to an appropriate value and the statistical uncertainty to zero 2 Do a Peak Search and view the report on the screen Click on lines in the report to review the values of Integral and Power which seem to provide the cutoff sensitivity you desire Or look at the ratio of the net counts to the uncertainty in the net counis to decide how much uncer tainty you think there might be in the weakest peak you wish to consider 3 Change the settings in the Tool Setup dialog box If there are too many peaks found reduce the sensitivity by entering lower Integral values and or higher Power values Once you have set reasonable values of Integral and Power the uncertainty adjustment is often the most useful 4 Redo the Peak Search One or two passes through the above process should give you the desired sensitivity Keep in mind the following general rules You can use larger values in
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142. m PP GIT PRINCETON GAMIMA TEGH To allow the user to set a few manual background ROls and use the default background ROIs else where the system must know how far from the peak the user expects to set ROIs If a user defined background ROI is not found within the Capture Range it is assumed that the default background ROI computation is appropriate The capture range is set in channels so that it is easy for the user to tell whether a background ROI is close enough that it will be used Note that a background ROI might be used by multiple peaks if it falls within the capture range of all of them so a smaller capture range pro vides better control over which background ROls are used for which peaks MDL Parameters The MDL Parameters Minimum Detectability Limits panel allows better control over the presentation of the MDL HDL Parameters 270 4650 V Bkg Re See Analyze Rapid Scan on page 109 for a detailed discussion of the equation The two fields here let you adjust the values used in the equation ROI Analysis Control ROI Analysis Control is used to determine how the system will calculate backgrounds ROI Analysis Control W Ambient BKG Correction W Continuum BKG Correction In QuantumMCA only Continuum BKG Correction is used In the continuum background mode the system uses a background ROI on each side of an unknown ROI to draw a straight line under the peak The system then subtracts off the counts und
143. m cursor to that location in the spectrum PPGT Analysis Tools PRINCETON GAMMA TECH 7 7 Peak Identify All Quantum Software Analysis Tools Peak Identify performs a qualitative match between the peaks found by the peak search tool and the radiation records in the current database Any radiation that falls within the energy window specified in the Tool Setup dialog is included as a possible candidate for the peak a Analysis Repor by Nuclide Ed File Repor Type NUCLIDES FOUND WITH HIGH PROBABILITY 8 592 B Corr Coeff 0 955 CENTER GROSS NET ROT keV cnts cnts ASS IGNMENT 123 16 209814 458 92692 666 Euls4 123 248 01 18761 137 14907 166 Euls4 247 591 92 5842 76 3613 112 Euls4 591 723 53 15534 125 13132 153 Euls4 722 757 03 4753 69 2413 111 Euls4 756 73 49 8144 90 6288 122 Ful348 873 996 61 6796 82 5400 109 Euls4 996 1005 10 10423 102 8709 130 Fu135481004 1274 90 13444 116 12495 131 Fu11 5481274 1596 91 770 28 694 34 Eul5461596 li BE HE e l O O e HE e e e m mn 20 do Ma do ds DO do po 3046 2 10 15 lines found corr 7696 9 27 6 lines found corr 200 6 1 15 lines found corr The exact energy window used at a particular energy can be found by looking at the E Window item in the ROI Detail report Note that properly calibrating the system for energy and resolution is very important for accurate results To get the fullest benefit from the Peak Identify function care sh
144. m of the equation used is Qt rdi tlta e Hbpip E Qe eit tila e 1 e Hm F E Here E is the full energy peak efficiency i e the fraction of the photons emitted by the sample at energy E which result in net counts in the peak of that energy measured on the spectrometer The first 113 114 Quantum PP GIT PRINCETON GAMIMA TEGH factor in the equation 3 is the fraction of 4x subtended by the detector While this does depend on energy to some extent we will assume it to be a constant unless specified otherwise The second term represents the effect of filtering out part of the incoming radiation by various windows and detector dead layers Most of the software provides for two window materials 1 2 and a dead layer d on the detector The third term accounts for the finite thickness of the detector Gamma rays of higher ener gies will mostly pass through the detector unless it is very thick The final term is a arbitrary function of energy which is used to take into account the remaining properties of the detector which cannot be easily predicted One of the primary ones of these is scattering within the detector Energy Dependencies The linear mass absorption coefficients u have strong energy dependencies At energies below 100 keV discontinuities exist at each of the K L M N O and P X ray edges for the elements making up the windows To accurately model these effects the software uses a subroutine library
145. m the Library database Energy Window When search algorithms are employed this is the delta in energy within which a line is considered matched controlled in tool Setup by Energy Window for Line Matching Table 7 1 ROI Details 70 Quantum HapGT PRINCETON GAMIMA TEGH 7 6 Peak Search The Analysis Tools Peak Search is the automatic qualitative analysis function This program searches the spectrum for peaks and generates a list of all peaks found An ROI of type unknown is set over each peak with a width set in the Setup Tool Setup dialog The width and placement of these regions are set in the Tools Setup dialog Ambient background and continuum corrections are applied according to the tools settings Ed Peak Finder Report Ed File PEAK CENTER Peak Finder chan KeV Int Power m Hali O CM Ha a PS 630960 3319 96054 62278 2418 137209 I co 1 FF HE HE e l B E t t 1 FF HE HE e HE B E D D D OD 220 20 m B 9 T 9 3 1 0 1 9 3 There are two different peak finding filters available The Low Peak to Background filter is a variable width top hat It finds very weak peaks but does not function well in cases of massive overlap This filter is often a good starting point because it tends to be less sensitive to the detector resolution and it is easy to limit excessive peaks by modifying various cutoff parameters The Overlapped Peak filter uses
146. mouse button on one of the red lines and drag it in or out as desired 18 Quantum PP GIT PRINCETON GAMIMA TEGH 2 1 2 3 Vertical Controls The vertical display controls include a Lin Log Sat 28351 S m Auto readout of the maximum displayed verti cal range counts Select Auto to enable autoscaling In this mode each spectrum is individually autoscaled n linear and square root modes the highest point in the visible region of the spectrum is adjusted to 96 of full scale In log mode the closest decade is selected If the displayed horizontal energy range is moved the vertical range will be adjusted to reflect the highest peak in the new region The full scale value displayed is that of the primary spectrum If a new value is entered the system will use this as the new full scale value and turn off autoscaling if necessary To compare the absolute heighis of several spectra do NOT use autoscale Click to select linear square root or log vertical scales The linear and square root modes provide scales from 16 to 2 by powers of two The log mode provides a scale of 105 to 105 full scale To change the displayed vertical range click the Expand Vertically and Contract Vertically buttons Each click changes the displayed range by a factor of 2 or by a decade in log mode You can also type a vertical scale value directly into the white text box After entering the value press the keyboard TAB key The new value
147. must carefully select the correct settings for the tasks you are performing since inappropriate selections can produce invalid analytical results 57 58 Quantum EPGT 6 6 1 Configuring the Tool Setup Choose Setup Tool Setup to open the Tool Setup dialog box below The Tool Setup dialog box includes an interactive graphic to help you understand how the different settings can affect your analy S S Tool 5eluy Mode Energy RO See Winda amp Low Pk to Bkg Below Initial setup for Nal detectors Sensilivity Limits in QCC mode R l Width EgitoolSetup Mode 250 E FWHM o Oveklapped Low Pk to Bkg Background Parameters Sensitivity Energy Window for Line Matching Width Gap A Low Energy Cutoff E Ax FWHM C A B x Energy E 0 0 Chans FWHM 0 500 E 0 000 Stat Uncertainty ADI Analysis Control ooo Use Library Efficiencies F W Ambient BEG Correction cane Continuum BEG Conmeaction Manual Background ROI Copture Range Spectroscopy Type Channels 32 FWHM A s B x Energy E Gamma MDL Parameters Beta A 8 000 B 0 055 FUI Analpsis Control 12 Ambient BEG Corection Conimuum BEG Conection eno Bkg F Y L APPLY EXIT Above Typical initial setup for germanium detectors Channels RE HDL Parameters z710 4650 V kg F r Mode Setting All of the peak fin
148. name Do not use the following characters in the name Click Delete to delete a standard Once you delete a standard you cannot retrieve it Click Save to save the new or edited standard to the database Click Exit to close the Edit Standard dialog box PPGT Setup Menu 45 PRINCETON GAMMA TECH 6 2 3 Coarse Adjustment The coarse adjustment procedure adjusts the MCA hardware and performs a linear energy calibration Normally you will only need to perform a coarse adjustment before using your system each day but you might need to run the adjustment more than once a day if major changes are made to your detector or MCA To perform a coarse adjustment e Select the Cs137 calibration standard from the Calibration Standard menu in the System Auto Calibrate dialog box This standard must match your source e Position your Cs137 source in front of the detector and click the Cs137 Coarse adjust but ton You do not need to know the precise activity of your Cs137 source but note that the calibration can operate reliably only if the peaks are at least twice as strong as the ambient background e f a calibration already exists you will be asked if you want to replace it with the new linear calibration If all you need is a coarse adjustment for example if the temperature of your Nal detector has changed click No The software will retain the quadratic calibration and simply adjust it into place with the new coarse adju
149. nators such as MUL which indicates the line is a multiplet combination of other lines the actual lines are generally also included in the database This method of representation is particularly useful in libraries specifically intended for Nal based analysis where the detector resolution is not very good The WTCLIB MDB database makes extensive use of this approach ENERGY The energy of the radiation in keV followed by uncertainty BETA END Pt For betas only the end maximum energy of the radiation followed by uncertainty RAD INTENSITY The frequency of this radiation per 100 decays followed by uncer tainty EFFICIENCY Automatically filled in by the isotopic efficiency calibration function of Auto Calibrate Although the field is editable you should not modify the contents It is followed by uncertainty SUMM CORR The summing correction to be applied to each line of the nuclide in the calculation of activities It is a multiplier applied to the net counts of the line before the activity is computed This is useful in applica tions where true coincidence summing occurs such as in measuring Eu152 in a well detector Be extremely careful when attempting to use this parameter DOSE Dose in grad uCi hr USE This flag indicates that the line is displayed and used in searches of PPGT Edit Menu 39 PRINCETON GAMMA TECH the database You can add or delete library files to or from the lib directory Only valid mdb Quantum libra
150. nching The occurrence of two or more modes by which a radionuclide can undergo radioactive decay For example RaC can undergo a and b decay 9 can undergo b b and electron capture decay An individual atom of a nuclide exhibiting branching disintegrates by one mode only The frac tion disintegrating by a particular mode is the branching fraction for that mode The branching ratio is the ratio of two specified branching fractions synonym multiple disintegration Calibration System calibration involves correlating energy with MCA channel assignment Cascade A way of arranging open windows on the desktop so that they overlap each other with the title bar of each window remaining visible Cascading Menu A menu that opens from a command on another menu Check Box A small square box that appears in a dialog box and that can be selected or cleared When the check box is selected an X appears in the box A check box represents an option that you can set Choose To use a mouse or key combinations to pick an item that begins an action in Windows Circuit Anticoincidence A circuit with two inputs which delivers an output pulse if one input terminal receives a pulse but delivers no output pulse if pulses are received by both input terminals within an assigned time interval Click To press and release a mouse button quickly Close To remove a document window or application window from the desktop You can choose to save or aban
151. nction is not available if the ROI Data Panel is visible because the mouse is then used to set clear ROIs Title Bar The horizonial bar located at the top of a window and containing the title of the window On many windows the title bar also contains the Control menu box and Maximize and Minimize buttons Toolbar The graphic butions located just under the menu bar that provide access to various display or control functions These tools are similar to the function keys in DOS Transient Equilibrium An equilibrium condition atiained when a nuclide parent decays into another nuclide daughter and the hal life of the daughter is less than the half life of the parent In transient equilibrium the ratio of the activities increases with time at first and then approaches a constant value greater than unity Secular equilibrium is the limiting case of transient equilibrium when the daughter half life is much less than the parent s half life Transient equilibrium is observed in both the natural decay series of Th and U and in beta decay chains Wildcard Character A character that represents another character In filenames you can use the asterisk as a wildcard character to indicate any character or group of characters that might match that position in other filenames For example EXE represents all files that end with the EXE filename extension X Rays Penetrating electromagnetic radiations having wavelengths shorter than those of visible
152. nd Background Parameters These sections give you control of The ROI width for the peak The number of background channels e A desired gap between the peak and background ROIs The energy range of an ROI set around a normally distributed Gaussian peak is given by multiplying the ROI Width factor by the resolution of the peak The resolution in keV is determined as the full width at half maximum of the peak as determined by the resolution calibration If no resolution calibration is available a default width is used ROI Width 2 50 xP HH The ROI peak width is defined in terms of the full width at half tenth fiftieth and hundredth maximum To set an ROI equal to the FWTM of a peak set the ROI peak width parameter to 1 823 FVHM Full Width at Half Maximum VVidth at Half Maximum 1000 000 2355 395 FWTM Full Width at Tenth Maximum 1 823 4 292 FWFM Full Width at Fiftieth Maximum 2 375 5 594 FW 01M Full Width at Hundredth Maximum 2 583 6 070 Table 6 2 Definition of Peak Resolution Terms PPGT Setup Menu 61 PRINCETON GAMMA TECH You can also set the ROI width by selecting the desired two sided confidence interval The data in Table 6 3 present the ROI width factor as a function of this confidence interval To request an ROI width that will include 30 or 99 7 of the peak s counts set the ROI width factor to 2 55 Confidence Interval Width Factor 99 995 3 404 Table 6 3 ROI Width Factor for V
153. nd click the right mouse button to make that point the center point on the screen and simultaneously increase the horizontal expansion by a factor of two 10 Quantum PP GIT PRINCETON GAMIMA TEGH e f the new horizontal expansion is set so that the selected point cannot be made the center for example if you are viewing full scale and click at 1 8 scale there will be some expan sion but the point will not be exactly centered 1 8 4 Detaching the Cursor from the Mouse Except during live display you can gain keyboard control of the cursor when full height no auxiliary display is selected on the main toolbar Press CTRL D This will detach the cursor from the mouse and allow you to move it channel by channel with the arrow keys on the keyboard To reattach the cursor to the mouse press CTRL F You can use the disconnected cursor in all modes including ROI setting as described below 1 8 5 Keyboard Controls You can use keystroke combinations to control certain features of the MCA These shortcuts are partic ularly useful when you want to set ROIs or precisely move the cursor CTRL D Detaches the mouse from the cursor The cursor will appear as a full height white line This mode is not recommended for use while in live display CTRL F Reattaches the mouse to the cursor CTRL S If the cursor is detached starts the setting of an ROI CTRL E If the cursor is detached ends the setting of an ROI CTRL A Starts data acquisition
154. nergy calibration uses a multi line standard containing five or more lines to compute a qua dratic energy calibration of the system Eu152 is a good single isotope standard for this purpose since it has lines from 40 to 1408 keV If your work involves a different energy range select a standard or com bination of standards that cover the range in question To perform a fine energy calibration e Select the calibration standard from the Calibration Standard menu in the System Auto Calibrate dialog box Make sure the standard has lines which completely span the energy range of interest e Position the standard source in front of the detector and click Fine Energy Cal If there is no data in the primary live memory the energy calibration function will automati cally acquire new data and perform the calibration If there is data in the primary memory when you start the calibration you will be asked if you want to use the current data or take new data This option allows you to use a previously collected standard spectrum HpGT Setup Menu 47 PRINCETON GAMMA TECH e A calibration report and a display indicating how closely the lines match the standard shown in the example below are generated in the System Auto Calibrate dialog box Biel E in System Auto Calibrate File Setup Eff Cal Calibration Standard Eu152 Status 181 7 Elapsed Real Time 180 0 Elapsed Live Time 6 195 Peak Counts C137 Coarse adjust F
155. nged to suit your preferences Select Setup Select Display Colors to open the panel RGB color bars in Select Display Colors Drop down menu Selected color Hue selection bar Color saturation box Graphic display PPGT Setup Menu PRINCETON GAMMA TECH The display includes a graphic with all colored items in the spectrum display The eight lines at the right in the graphic represent the eight spectrum memory buffers while the spectrum in the display is shown in the primary spectrum color Select an item from the drop down menu and then select a color with the controls As you do so the item in the graphic display will change accordingly You can see whether the items of interest to you show up against the background and contrast sufficiently with each other To change the color of an item select the item from the drop down menu Then click the left mouse in the Hue selection bar and drag the rectangle to the desired color area That color will be shown at the upper left corner of the Color saturation box The upper right corner represents white while the bottom is black Click the left mouse button in the box and drag it around As you do so you will see the color become brighter deeper or lighter depending on where you are in the box The RGB color readouts will update as you move the mouse The color at the current position of the cursor in the Color saturation box is shown in the Selected color rectangle The color of th
156. not clear the buffers at power on If the device still does not respond consult the troubleshooting section of your hardware manual or call tech support Quantum PP GIT PRINCETON GAMIMA TEGH When the software starts it will restore the complete working environment from the last time the pro gram was executed The first time the program is run the user should check all hardware parameters to ensure they are correct for the hardware connected to the system 1 6 Setting Up the System Before you start collecting and analyzing data you must set system preferences and calibrate your system It is strongly recommended that you read the relevant sections in the manual so you under stand how the Quantum software works Before starting data collection read the procedures in Section 9 see Procedures on page 76 to familiarize yourself with the basic system operation 1 Choose Setup Detector Parameters from the main menu to set up your detector parame ters see Detector Parameters on page 55 2 n the Hardware Control panels see Hardware Control Panels on page 22 verify the cor rect settings for your system 3 Select Setup Tool Setup and make sure the items correspond to the default settings appro priate for your system see Tool Setup on page 57 4 Calibrate the system see Automatic Calibration on page 42 and Manual Calibration on page 52 1 7 Spectrum Display and Memory Con
157. nt Pure substance consisting of atoms of the same atomic number which cannot be decom posed by ordinary chemical means Energy lonizing The average energy lost by ionizing radiation in producing an ion pair in a gas or to create an electron hole pair in a semiconductor For air it is about 33 eV for high purity Germanium it is 2 95 eV pair Excitation The addition of energy to a system thereby transferring it from its ground state to an excited state Excitation of a nucleus an atom or a molecule can result from absorption of photons or from inelastic collisions with other particles File A document or application that has been given a name All documents are stored as files in Win dows Filename The name of a file Windows uses DOS file naming conventions Gamma Per Decay Abbreviated GPD this quantity is expressed as percent in our libraries and man uals The quantity is a ratio of the number of gammas emitted from the sample per 100 nuclear transi tions In prompt gamma libraries this quantity is the number of gammas per 100 neutrons captured More properly this quantity GPD should be called gammas per 100 nuclear transitions to account for all applications The quantity GPD is used as a fractional value in the activity equation for gamma spectroscopy Gamma Ray Short wavelength electromagnetic radiation of nuclear origin with a range of wave lengths from about 108 to 10 cm emitted from the nucleus Geometry G
158. ntegral of the positive lobe of the filter function divided by the width of the lobe This parameter has the greatest effect on finding small wide peaks such as those that might exist in Nal spectra for wipe analysis Both parameters are reported in the Peak Search report to allow the user to customize the results more easily To decrease sensitivity increase these values Limits Limits settings filter out particular peaks after the convolution has done its work If you have a detector which cannot detect any events below a given energy set the Low Energy Cutoff to this value in keV This is a simple way to prevent any lines Low Energy Cutoff in this energy region from being included in the analysis Suggested values are 20 EM keV for Nal or P type germanium detectors 10 keV for N type germanium with an 22 Stat Uncertainty aluminum window or 3 keV for N type germanium with a beryllium window a The Statistical Uncertainty limit allows you to filter out peaks based on the sys s Dev tem s computed confidence intervals For example a setting of 3 00 would require a peak to be three times stronger that the standard deviation of the counting statistics for that peak A setting of zero is used to turn off this limit so that every peak is found regardless of its uncertainty Limits Energy Window for Line Matching When the software tries to identify peaks or perform quantitative analysis it must compare the energ
159. nto 4 9 equal energy divisions The number of divisions is selected automatically as a function of the energy range displayed Horizontal grids are provided in overlaid mode or single spectra display The screen is divided into eighths by the horizontal grids in linear mode In log mode grid lines are drawn every decade Redraw is the screen refresh feature Background shovv no show subtract leis you display or subtract the ambient back ground spectrum that you acquired and designated with File Use as Background No show displays just the spectral data 2 1 2 Adjusting the Display Range There are three ways you can adjust the horizontal and vertical display range of a spectrum Use the mouse buttons also see Right Mouse Button on page 9 Use the control buttons on the right side of the toolbar e Adjust the range within the spectrum display itself PG T Main Display 17 PRINCETON GAMIMA TEGH 2 1 2 1 Horizontal Controls Each time you click Compress Horizontally far left or Expand Horizontally left the viewed energy range contracis or expands by a factor of two The center of the new dis play will be the same as in the previous display Use the scroll bar along the bottom of the display window to change the region of the spectrum being viewed The readouts on the lower left and right of the data display Eg T 208647 show the upper and lower limits of the displayed energy range
160. o stop before the preset time press Stop You may start and stop as often as you wish Data will continue to be added to the same spectrum To delete the present data and start a new spectrum press Erase and then H 9 7 Acquiring and Using a Background Spectrum As a regular part of the daily routine collect an ambient background spectrum This is a spectrum col lected with no source or sample in the vicinity of the detector It is meant to account for the usual back ground in that area at that time 1 Enter the desired Live Time in the Presets tab of the hardware control panel and click Enable Presets As a rule a background spectrum should be collected for longer than the usual data collection For example if 300 sec is the usual collection preset time collect the background spectrum for 600 sec or more 2 Press the Acquire button B Observe the spectrum If there is unusual activity check for sources of contamination usually samples or sources that are still in the vicinity Click Erase F and then H after the area has been cleared 3 When the background spectrum has been collected select File Use as Background This spectrum vvill novv serve as the ambient background spectrum for all spectra collected vvith this particular device until a nevv background spectrum is collected and designated as above or until File Clear Background is selected 4 VVhen you have collected a sample spectrum you can see hovv the back
161. ometric efficiency associated with sample detector geometry is important By modeling these three primary aspects of the detector efficiency we are left with a residual which has only very slowly varying energy dependencies The primary unaccounted for effect remaining is Comp ton scattering in the detector Since the above model computes the total fraction of photons which deposit their energy in the detector it is an overestimate of the number of photons counted in the photo peak because many of the photons are scattered to lower energies For this reason it is very important to fit the residuals from the model to actual data to get an accurate estimate of the detector efficiency This residual we can then fit to an empirical function Through this half modeling half empirical approach we can achieve accurate efficiency fits over a very broad energy range B 1 Common Parameters for ALL Detector Types The efficiency of a gamma ray or X ray detector is determined by its physical dimensions the position of the source relative to the detector and the material from which the detector is manufactured The effect of some of these parameters is independent of energy but most have strong energy dependen cies The model which we adopt as a general form attempts to include the easily predictable energy dependent effects based on the system s known geometries while compensating for unknown effects through the use of fitting parameters The general for
162. ons to be computed for previously acquired or imported data 50 Quantum WPGT PRINCETON GAMIMA TEGH The dialog box below shows the equation with the peaks used in the efficiency calculation The green line is the efficiency curve which appears only if the detector efficiency has been calculated see Effi ciency Curve on page 50 in System Auto Calibrate File Setup Eff Cal Biel Es Calibration Standard Status Elapsed Real Time Elapsed Lire Time Peak Counts C137 Coarse adjust Fine Energy Cal 1112 116 1469 96 14H8 H11 1 9586 Energy A B s Channel s Channel where 4 1 867E HH 2 228 84 The efficiency results are stored in the currently selected nuclide library Quantum Note Be careful to select the correct nuclide library before doing a calibration so that the results will be stored in the correct place 6 2 8 Efficiency Curve The detector efficiency is calculated from the efficiencies stored in the current Library The equation with the appropriate constants is then stored with each spectrum collected with this detector WPGT Setup Menu 51 PRINCETON GAMIMA TEGH e Click Eff Cal in the System Auto Calibrate dialog box to open the Detector Efficiency Calibration dialog box below showing all lines in the current Library that have efficiency data stored i Detector Efficiency Calibration Exit Isotope Energy Intensity Efficiency Measured Ca
163. ood In nuclear physics measurements an arrangement of source and detecting equip ment so that the use of finite source size and finite detector aperture introduces little error Ground State The state of a nucleus atom or molecule at its lowest energy All other states are excited Guard Detector A detector used in anticoincidence counting to reject events from cosmic rays or other background sources When an event occurs in both the sample and guard detector within an assigned time interval the count is not added to the channel accumulating the data Half Life Radioactive Time required for a radioactive substance to lose 50 of its activity by decay Each radionuclide has a unique half life Half Value Layer Half Thickness The thickness of any particular material necessary to reduce the intensity of a radiation beam to one half its original value Hardware Controls A data panel providing access and editing for hardware setup Each type of sup ported hardware will have a panel specific to its available features Icon A graphical representation of various elements in Windows such as disk drives applications and documents lon Pair Two particles of opposite charge usually referring to the electron and positive atomic or molecular residue resulting after the interaction of ionizing radiation with the orbital electrons of atoms lonization Density Number of ion pairs per unit density PPGT Glossary 129 PRINCETON G
164. or efficiency Because Rapid Scan uses ROI widths which are directly related to the resolution of the detector at the given line energy it is most reliable when used on single resolved lines in the spectrum If you are working with spectra with broad groupings of lines for example Ba133 on a Nal detector Analyze with Deconvolution Section 7 9 or Analyze ROI Directed Section 7 10 are better approaches If ROIs exist in the spectrum when you select Analyze Rapid Scan you will be asked if you want to use the existing ROls or not If you select No the spectrum will first be searched for peaks using the Peak Search program A good approach to analysis is to run Analyze Rapid Scan examine the ROIs it sets and edit them as required The following is the type of editing that should be done 1 Delete any ROls which are not real peaks such as Compton edges 2 Widen narrow or shift ROIs if they do not match the peak perfectly this can be especially useful on multiplets or annihilation peaks where the original ROI may be too narrow After editing the ROls run Analyze Rapid Scan again The software will then compare the ROls in the spectrum with those isotopes in the library which have Use True enabled In step one of the analysis the software determines how many of the enabled lines of each isotope are matched to ROls in the spectrum If at least one line matches then the system computes a cross correlation coefficient between
165. ore information on the Ba ade tool or for details on procedures select Help Contents to open the easy to use About MCA Windows On Line Help function 8 1 Contents Select Help Contents to bring up the Windows Help system Contents for the PGT Quantum MCA software Main topics may be accessed directly In addition the Index and Find tabs allow quick Click a topic and then click Display Or click another tab such as Index access to specific topics Many help topics are cross referenced allowing related information to be quickly displayed A single underline indicates a cross reference topic for that word A dashed underline indicates that more information for that word can be displayed in a pop up window When Help Topics Quantum HCA EA EI Contents Index Find Introduction lg Spectrum Display Features m nnotated Spectrum Display Horizontal and Vertical Range Controls gt Main Tool Bar Data Controls ROI Tool Bar Menus the pointer is over one of these items or over a Fie Menu hypertext graphic it changes to a pointing finger 7 Click to go to the reference or display the pop up li Setup Menu The Setup Menu Detector Parameters Double click on the Annotated Spectrum Display a x help item in the Table of Contents This entry pro vides quick access to help for all main screen items Pit Cancel when you point to the item on the screen and click
166. orts Finals ba bed Send to Printer as Color Send to Printer as B amp W For Quantum products with quantitative analysis capabilities you can select the pre Activity Units pr id ferred activity unit in the Activity Units box Una GREY RE ER All report parameters are saved and restored Energy Calibration Info i 29 Efficiency Calibration Info each time the program is started ee CS General Spectrum Info Tool Setup Info MCA Hardware Info 3 0 2 Printer Setup Preset Info Choose Printer Setup to access the Win dows printer setup capabilities You can select a new default printer or change the current settings 34 Quantum HPGT PRINCETON GAMIMA TEGH Note that all changes you make in this dialog box affect the default Windows printer 3 1 Last File Group The four most recently loaded or saved ANS or OXS spectrum files are displayed for convenient retrieval Select one of these files to load it into the first available buffer in the same way as Load to Buffer PPGT Edit Menu 35 PRINCETON GAMMA TECH 4 Edit Menu The Edit menu contains commands allowing you to e Copy a bit mapped or metafile image of a spectrum to the clip board Copy Spectrum to Clipboard Copy Metafile to Clip emo lisas to board Copy Spectrum to New blemon System Parameters Copy a spectrum to a new buffer Copy Spectrum to New AR MIT eee Memory Library
167. ould be taken in selecting the library to use Select or create using the optional librarian or by cloning an existing library a library that has only those nuclides with some probability of appearing in your samples Filter from the library those radiation records that are of the wrong type or that are very weak With a properly built library the output from peak identify should be very useful 7 7 1 Report Formats The report generated by the Peak Identify routine as well as those from Rapid Scan and ROI Directed procedures can be displayed with various formats The default is the Report by Nuclide as shown above In this format the results are categorized with those identified with high probability first followed by those with just some lines found low correlation those nuclides rejected and finally those lines not matched to any library isotope To change the report format click Report Type in the report window menu bar The By Line selection will display the ROI data for each ROI There are five ROI columns across the row You must scroll down to see the next group of five The Line Summary selection simply reports the ROIs in order with their centroids gross and net counts nuclide and ID The first column may show VV or O on some lines W indicates that the stored FWHM for the ROI is less than 0 66 times the calculated FWHM at its center energy O indicates over lap either the line is separated from its
168. pectra in tiled mode This spectrum will show jus lire peaks found with no background PRINCETON GAMIMA TEGH PPGT Procedures 91 9 17 Quantitative Analysis ROI Directed This is another approach to analyzing multiplet or overlapped peaks 1 Collect the spectrum and get the initial ROIs with Peak Search or Rapid Scan or by manually creating the ROIs 2 Edit the ROIs as needed For an overlapped peak make sure the ROI extends over the entire peak 3 Use ALT left mouse to select the nuclide line for each ROI An unidentified red ROI will not be analyzed 4 Select Analysis Tools Analyze ROI Directed Quantum PRINCETON GAMMA TEGH PPGT QScript 93 PRINCETON GAMMA TECH 10 QScript QScript is a script creation tool editor and player The QSCRIPT EXE file is installed automatically as one of the icons in your program group Double click on the QSCRIPT EXE icon to start the program It will automatically start the Quantum software and connect to it The message line at the top will report Connected to Quantum To con nect to software manually select the appropriate software from the list under the Connect menu Quantum software must be running to create or play back a script During script creation it is a good idea to observe the spectrum display However you may minimize it to an icon in the task bar while running a scripted analysis Change the number in the text box next to the Primary command
169. play Annotation Text Overlapped peaks Next Previous E Delete Clear All gt R Once you have placed an annotation in the spectrum display window you can choose Edit Edit Screen Annotation to open the Annotation Editor dialog box and edit or delete any of the currently displayed annotations Use the Next and Previous buttons to move from one annotation to another Edit Menu 37 PRINCETON GAMMA TECH You can edit annotation text that appears in the white field To adjust the placement of the active anno tation click the arrow buttons The right and left arrow buttons move the annotation one channel at a time so you may need to repeatedly click the arrow buttons before you notice a change If you place the annotation in the full scale display it may disappear temporarily when you expand the energy range To see it again simply return the display to full scale mode Annotations can also be added to an expanded display Click Delete to erase the currently displayed text Click Clear All to remove all manual annotations Note The commands in the Annotation Editor dialog box do not affect marker labels 4 4 Nuclear Library Editor All Quantum products use database libraries of nuclides to analyze spectra To select a library click the Library button on the toolbar to open the Select Library dialog box Quantum can also use any library created with Quantum Librarian sold separately You can edit and clon
170. r devices with a fixed range this field will be hidden If the device allows the stabilization sample interval to be adjusted you may enter this value into the time constant field If you enter zero the behavior is device dependent For devices which support an automatic time interval this will select that mode However for devices which do not support this it will effectively turn off the stabilization You may select any foreground ROI for stabilization As the stabilizer runs its current value in percent of full scale will be shown in the value field To reset the stabilizer to center thus eliminating any com pensation it has done simply press the reset button 25 26 Quantum HapGT PRINCETON GAMMA TECH 2 3 5 External Controls Pre mp bias Amplifier Selectable ROI Map Output All A number of miscellaneous controls are placed on the External Controls tab Some MCAs support connections to an external ADC and for these devices the external ADC control word may be neces sary to set up the interface correctly The external sync mode if selected allows acquisition to be con trolled by external inputs to the ADC usually in addition to the normal control through the Acquire button Some ADCs have one or more built in DACs that can drive voltage outputs For a live device it is possible to tell the voltage range on the output of the DAC from the message below the window An out of range value will set
171. r Analyze Rapid Scan routine PRINCETON GAMIMA TEGH PPGT Procedures 79 9 5 Identifying ROIs There are several ways to manually identify peaks in a spectrum It is usually best to expand the spec trum display so that the peaks can be seen more readily Make sure you have the proper Library selected for your type of spectra alpha beta or gamma or a user created library Click to select a library Also enable the ROI labels Mega 1 Section 2 1 4 Bring the cursor into an Unknown ROI hold down the key page 19 board ALT and click the left mouse button A pop up will show the possible nuclides within that range Click on the line you believe is most likely The corresponding nuclide label will appear on the peak in the spectrum and the ROI will change to green The ROI field in the toolbar will also change to green and report the selected nuclide Nuclide Energy Intensity Click on the next unidentified ROI and repeat the process To look at all the lines associated with a nuclide select it from the Isotope drop down list at the top of the display The Show Hide Markers button must be set to Show Markers All lines for that nuclide will be labelled as selected in the Marker menu panel You may have to compress the spectrum display range and or scroll through the energy range to see all the lines If not enough peaks correspond fo the lines for the selected nuclide your original identification may be wrong or
172. re Internally the software maintains a complex structure for each ROI See ROI Details on page 68 for a description of the information stored in this structure ROI information is updated whenever the spec trum data changes During data acquisition it is continuously updated Quantum software can store and process up to 500 individual ROIs per spectrum with a limit of 250 each of foreground and back ground ROIs Overlapped ROIs are also supported 2 2 1 ROI Markers ROI markers are used in the automatic peak identification programs They determine the display of Click Show Hide ROI Labels to show far left or hide left the lines and hirs HER labels corresponding to the ROls that have been set If the ROI is calcu label vvill display the name of the nuclide M Fu Click Nuclide Full ID in Labels to label ROls by nuclide far left or full ID nuclide plus energy line left markers and labels for the ROls lated automatically for example using a peak identification process the Hi m Click Show Hide ROI Markers to display vertical line markers for the ROls far left or suppress their display so that labels appear to float on the display left 2 2 2 Clearing ROls These buttons in the ROI toolbar allow you to clear ROls after they have been set Clear foreground ROls qe ALL ROIs Clear background ROls Clear currently selected ROI 2 2 3 Editing ROls These buttons on the ROI toolbar allow you to edit RO
173. re Princeton Gamma Tech Instruments further grants you the right to make a backup archival copy of the software CDs as set forth in the Notification of Copyright above You may not decompile disassemble reverse engineer copy transfer or otherwise use the Software except as stated in this Agreement Quantum Software User Manual PP GIT PRINCETON GAMIMA TEGH LIMITED WARRANTY LIMITATION OF REMEDIES Princeton Gamma Tech Instruments PGT will replace at no charge defective CDs that are returned within 90 days of the original date of purchase and warrants that the Software will perform in substantial compliance with the written materials accompanying the Software If you report in writing a significant defect to PGT and PGT is unable to correct it within 90 days of the date you report the defect you may return the Software and accompanying materials and PGT will refund the purchase price SUCH WARRANTIES ARE IN LIEU OF OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE SOFTWARE AND THE ACCOMPANYING WRIT TEN MATERIALS IN NO EVENT WILL PRINCETON GAMMA TECH INSTRUMENTS BE LIABLE TO YOU FOR DAMAGES INCLUDING ANY LOSS OF PROFITS LOST SAVING OR OTHER INCIDEN TAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF YOUR USE OF OR INABILITY TO USE THE PROGRAM EVEN IF PRINCETON GAMMA TECH INSTRUMENTS OR AN AUTHORIZED PRINCE TON GAMM
174. rea in metafile format The metafile can be copied into another application and resized if necessary The spectrum display is saved with a white background for printing 32 Quantum PRINCETON GAMMA TEGH To save a file in metafile format enter the file name in the File name box in the Save Spectrum as MetaFile dialog box and click Save 3 5 Sistem Configuration Files Choose File Load System Con figuration to load the hardware Ed Select Setup Options To Load parameters tool setup calibrations Select options to be restored to current device or spectrum and detector parameters saved from one spectrum to the primary C Load All MCA Setup Information spectrum This operation is comple p eg y nnn mentary to the Load Spectrum Te I ee Data Only selection The spectral Hardware Parameters data remains unmodified but the hardware parameters calibrations and tool setup are loaded from the Tool Setup specified file Load Cancel Load dialog box select all of these items or only a selected subset This makes it possible to apply the same set of calibrations to a number of spectra already present in memory Any prior parameters and calibrations will be replaced by those loaded from the MCA config uration file Calibrations and Detector Parameters In the Select Setup Options to Select the desired parameters and click Load The Load MCA Setup dialog box will open with the list of a
175. rivative 2nd Derivative Top Hat Peak Finder Original Peak Smooth A quadratic smooth after Savitzky and Golay Anal Chem 36 1627 1964 Smoothing func tions over 5 to 25 points are available The original spectrum is not affected A new memory is selected and the result of the smooth placed there The difference between the original spectrum and the smoothed result is displayed in the auxiliary spectrum display First Derivative Smoothed first derivatives after Savitzky and Golay Anal Chem 36 1627 1964 Smoothing functions over 5 to 25 points are available The result of the operation is displayed in the aux iliary spectrum Second Derivative Smoothed second derivatives after Savitzky and Golay Anal Chem 36 1627 1964 Smoothing functions over 5 to 25 points are available The result of the operation is displayed in the auxiliary spectrum Top Hat Filter Top hat filters with widths from 5 to 101 poinis are provided The result of the operation is displayed in the auxiliary spectrum Peak Finder This is a special variable width top hat filter for peak finding The width of the top hat used at a particular energy is a function of the system energy resolution at that energy The result of the oper ation is displayed in the auxiliary spectrum The convolution output can be observed in the auxiliary spectrum panel ae Quantum PGT PRINCETON GAMIMA TEGH 7 3 Channel Data The report generated by Analysis Tools
176. rker Label row allow you to select labels for the marker lines You can choose No label No Labels Nuclide symbol only Nuclide Nuclide symbol with its energy Nuclide Energy mm The commands in the Tag row allow you to choose Both marker line and tag Line amp Tag e Only tags Tag Only 2 1 4 Manual Peak Identification To see what nuclide lines might correspond to a particular peak in the spectrum e Bring the cursor to the center of the peak Press and hold the keyboard ALT key e Left click The Line List pop up window right will list the possible lines with their energies and intensities As you move the pointer from peak P ER to peak press ALT and left click the information in this window 57 5 671 4 will update to correspond to the selected peak This will give you an idea of what elements might be present 20 Quantum PRINCETON lf an ROI has been set over the peak click on a line in the Line List pop up window to place a label on that peak The Show Hide ROIs button must be set to Show To see all the lines associated with one of these nuclides click the Isotope drop down list All isotopes in the current library are listed alphabetically Select an isotope from the menu If Show Hide Markers is set to Show all the lines associated with this isotope will be labeled in the spectrum Identification depends on matching the spectrum peaks to the set of
177. ropsassd s g r 4 x RS ANTAS as 20 2 2 1 ROlMarkers 21 2 2 2 Clearing ROIS 21 22 0 EOtNng ROIS xu oxususux adunuaXusu us 21 2 3 Hardware Control Panels 22 2 3 1 Preamplifier and Bias Controls 23 2 3 2 Amplifier Controls 23 200 sap ku ks dine xd RE s RE TREO ESO 24 2 3 4 Stabilizers 25 vi Quantum PP GIT PRINCETON GAMIMA TEGH 2 3 5 External Controls 26 2 3 6 Presets 26 2 3 7 Multi channel Scaling Mode MCS 27 3 FileMenu 29 3 1 Spectrum File Types 29 3 2 Load Spectrum Options 30 3 3 mportUser 30 3 4 Save Spectrum Options 31 3 4 1 Save Display as Metafille 31 3 5 System Configuration Files 32 3 6 Background Spectrum Files 32 3 7 Managing ROI Files 33 3 7 1 ReportSetup 33 3 7 2 Printer Setup 33 3 8 Last File Group 34 4 EditMenu 35 4 1 Cop
178. rum for analysis To see them the ROI toolbar must be dis played ROls may be set by a Peak Search program or manually as follows He Edit View Setup Analysis Tools Help di Es te Lin Log Sgt 4607 d Iv b L B SAMMALIB MDB DT oz SELT 50000 Rate cps 2 Static 1 1048 1 Expand Contract LHS Adjust Section 2 2 page 20 21 1 Bring the cursor to the starting point hold down the keyboard CTRL press the left mouse but ton and drag to the end point The selected region will be red Release the mouse button The ROI will be red indicating an Unknown ROI The program will automatically assign the ROI number and temporary ID 2 To adjust the left edge of an ROI press the Compress and Expand LHS buttons to adjust the right edge click the corresponding RHS buttons To move the position of the ROI e g to center it better on the peak click the Move buttons To delete an ROI for example to start over or to eliminate an existing ROI from analysis click the left mouse button in the ROI to make it the current ROI Then click the right delete 41 If you routinely analyze for the same isotopes under the same acquisition conditions create the set of ROls for the analysis save that set File Save As ROIs and then load that ROI file File Load ROIs or File Merge ROls into each subsequent spectrum The ROls can be created manually as above or through a Peak Search o
179. ry files will be accessible to your application When you select a specific library a full check is made If any null fields are found the details are reported to the screen along with recommendations on using the Library editor to fix them if possible When you close the Nuclear Library Editor dialog box or change to a new library within the editor a full check is made of the library that has just been edited 4 4 2 Nuclear Library Editor Menu Options The Nuclear Library Editor dialog box contains several menu options File menu Data menu Clone Library Clear All Efficiency Data Print Current Nuclide Print Ordered by Muclide Print Ordered by Energy Close Quantum allows you to use the Clone Library command to make a registered copy of an existing library This is very useful in systems having multiple MCAs or multiple detector configurations on a sin gle MCA Since the efficiencies determined from standards are stored in the library different copies of the library must be used for each hardware configuration in order to get correct results To clone a library Choose File Clone Library to open the New Nuclide Library Name dialog box Enter a new name for the file in the File name text box and click Save Do not change the folder directory or the software will be unable to locate the new library File Print Current Nuclide will give you a printout of the nuclide information and line data for the cur rently display
180. s defined in terms of energy The most fundamental calcula tion in any spectroscopy program is the calculation of the data associated with an ROI In all PGT soft ware the data associated with an ROI is calculated by a single routine called ROlupdate Each ROI is represented by a structure a quantitative ROI containing both the fundamental characteristics of the ROI and all of the derived values ROlupdate calculates the following parameters from the start and end energies raw spectrum data and background spectrum data Gross Counts C Sc where C is the counts in channel i L L Background Counts B rae B B i s where B is the counts in channel i Lc is the elapsed live time of the spectrum being analyzed and Lp is the elapsed live time of the background spectrum The purpose of the ROI analysis is to accurately determine the net area of the peak To get the net area from the raw data two principal corrections are made The first is the subtraction of the ambient background The ambient background is simply the spectrum measured by the system when no sam ple is on the detector Because the count rate from the background is generally very low itis imporiant to take the background spectrum for long enough to get good counting statistics How the background statistics affect the uncertainty in the final answers will be discussed later HPGT Analysis Algorithms 105 PRINCETON GAMMA TECH B ROI BACKGROUND
181. s with most MCAs a Resolution Calibration should be performed prior to doing an actual peak search For PGT Quantum MCAs in QCC Quadratic Conversion Compression mode the peak width is set in channels since all peaks are the same width For QCC devices it is impor tant that the ROI Width parameter described below is set correctly since it determines the filter width for peak searches The Detector Type setting see Detector Parameters on page 55 also affects the expectations for peak widths and other search parameters Sensitivity and Limits are the two settings you will need to adjust most often Sensitivity The Sensitivity settings determine the size of peaks found by the search algo rithms Both algorithms filter the spectrum in a way that produces a positive lobe in the convolution result where a peak exists Values can be changed by selecting Integral the current value and entering the new one The arrow buttons change the value 200 by a factor of 2 Sensitivity 7 ala To view the convolution result click to select the aux convolutions setting using 10 the Auxiliary Display button on the toolbar alte For the system to find a peak both the power and integral requiremenis must be met A peak satisfies the integral requirement if the integral of the positive lobe of the filter function is greater than the spec ified value The power parameter is defined as the i
182. saved spec trum of this source 1 After the Cs137 Coarse Adjust or the Manual Two Point Energy calibration select Setup Auto Calibrate Open the Calibration Standard drop down list and select the standard that corresponds to your uu standard source See Section 9 10 for directions on creating a nevv standard file 2 Click Fine Energy Cal The display includes a graphic of the line match The scroll area has a listing of the nuclide lines and their errors the quadratic equation used to calculate the calibra tion and the sigma of fit i System Auto Calibrate File Setup Eff Cal mix Calibration Standard Eu152 Status 181 7 Elapsed Real Time 180 0 Elapsed Live Time 6 185 Peak Counts 5137 Coarse adjust Fine Energy Cal Resolution Cal System Quadratic Energy Calibration using 152 13 Lines of 13 matched in standard Efficiency Cal Energy Met Counts Standard 26554 43 82 39 522 26554 E E E a 50 50 5 50 5 50 aN G 5 5 5 5 9 9 3 Resolution Calibration After the quadratic energy calibration go on to the Resolution calibration Use the same spectrum Section 6 2 5 1 Click Resolution Cal The display again shows the graphic of the line match In the scroll area the resolution calibration data are added to the energy calibration data This includes the FWHM at each energy line for each nuclide the resolution equation and the sigma of fi
183. se are infrequent 124 Quantum PRINCETON GAMMA TEGH 322 Couldn t write desired data to file Writing to the file terminated prematurely usually because the disk was full or write protected 323 End of file reached unexpectedly The file was truncated or was missing a specific record used to mark the end of the file 324 Dialog canceled This is not an error but is instead used to indicate that the Cancel button was selected in a file dialog If this error message is reported the software has failed to trap this event properly Other error numbers between 400 and 599 are used to represent device specific hardware prob lems please contact us for further information if one of these errors occurs PPGT Glossary 125 PRINCETON GAMMA TECH Appendix E Glossary Some of the information in this glossary was drawn from Windows Reference Manual V3 1 WordPerfect Reference Manual Version 5 1 1989 and The Health Physics Handbook Absorption Self Absorption Absorption of radiation emitted by radioactive atoms by the material in which the atoms are located in particular the absorption of radiation within a sample being assayed Absorption The process by which radiation imparts some or all of its energy to any material through which it passes Active Describes the window or icon to which the next keystroke or command will apply If a window is active its title bar changes color to differentiate it vis
184. se values are continually updated The first character in this field identifies the number of the primary memory 1 Static m Live indicates that the memory is associated with a device that can be used to acquire data The field displays the name of the device connected to the memory The field is green if the device is ready to start acquisition yellow during acquisition and magenta when the preset has been reached Static indicates that the memory contains a spectrum loaded from disk The field displays the file name and is gray Failed indicates that the memory is holding a place for a device that failed to communicate The field is red Click the arrows at the right of the text field to move through every non empty memory even if it was not originally enabled in the Spectrum Display and Memory Control dialog box Each selected spectrum becomes the primary one and is displayed in white VFapiGT Main Display 15 PRINCETON GAMIMA TEGH 2 1 1 Display Control Buttons The set of buttons on the left side of the toolbar control the spectrum or set of spectra displayed in the main data display area their appearance and the additional information displayed with them Most buttons have multiple functions Click on each one to activate the different available modes dialog box The system provides eight memories for spectra This screen allows the user to select which spectra are displayed or to free memories See Selecting Spectrum
185. sedPass As Long 0112 Elapsed number of passes Deadtime As Single 101161 Instantaneous deadtime during acquire Average deadtime after acquire ElapsedCount As Double 0120 Elapsed count Hardware Setup Bias BiasOn As Integer 0128 On Off BiasCtrl As Integer 101301 Bias Control word xxxxSSSSAAAAxxxP SSSS shutoffs AAAA alarms spare extern LN2 leak bias polarity negative 1 positive BiasSetPt As Single 0132 Set Point for Bias Supply BiasVoltage As Single 0136 Voltage Setting BiasCurrentLimit As Single 0140 Current Limit in ma RESV0144 0 To 15 As Byte 10144 Reserved for bias info 116 Quantum Hardware Setup AMP AmpCoarseGain As Single 0160 AmpFineGain As Single 0164 AmpPoleZero As Single 10168 AmpShapingTime As Single 0172 AmpFastThresh As Single 0176 AmpBLRThresh As Single 10180 AmpShape As Integer 10184 AmpCtrl As Integer 0186 PreampType As Integer 0188 RSRV0190 0 To 33 As Byte 0190 Hardware Setup ADC ADCMode As Integer 0224 ADCCtrl As Integer 102261 ADCGate As Integer 0228 ADCDTMode As Integer 102301 ADCConvMode As Integer 0232 ADCMCSMode As Integer 102341 ExtADCCtrl As Integer 0236 ExtOutBits As Integer 02538 ADCZero As Single 0240 ADCLLD As Single 102441 ADCULD As Single 0248 ADCConvGain As Integer 0252 ADCGroupSz As Integer 0254 ADCGroup As Integer 0256 ADCDi
186. start of the area to be examined Press the right mouse button and drag to the end of the area of interest The selected area will be gray Release the mouse button Vertical Vertical Horizontal Range Adjust Adjust Quantum MCA Gold File Edit View Setup Analysis Tools Help el Em BT hasa FZE ou Move Range Button D Netlntegrakl FV HM minini FETA ds E Channel 1259 Counts 233 ROI Net Integral Centroid Display Limits 2 Inthe Auxiliary Primary display two red lines define the portion of the total spectrum that is displayed in the main area Press the left mouse button on one of these lines and drag to adjust the display range 3 To move the displayed area without changing the expansion bring the cursor to the square in the scroll bar press the left mouse button drag to the desired location and release the mouse button lf Auto is checked the highest peak in any displayed area will be shown at full vertical height that is the vertical range will change as shown in the counts box To keep this from happen ing click on the Auto box to uncheck it 4 Click max to return to the full spectrum range To change the vertical range click the Vertical Compress and Expand buttons Auto will be unchecked 18 Quantum PGT PRINCETON GAMMA TEGH 9 4 Creating Editing and Deleting ROls Foreground ROls define peaks in the spect
187. stment e The system will automatically start acquisition and adjust the coarse and fine gain with respect to the 661 keV line In some cases the system will adjust the bias voltage to achieve the desired full scale energy calibration For this feature to work the MCA hardware must support computer control of the amplifier Systems with external or fixed high voltage supplies are supported However when computer control of the HV supply is present and the detector type is scintillation the voltage will be adjusted before the gain These fea tures are found in all Quantum MCA2000 MCA200R MCA2100 and MCA2100R instruments and in the Oxford PCAP Sierra and MCArd5000 46 Quantum PRINCETON GAMIMA TEGH When the coarse adjustment is complete you will see the following display and report mix i System Auto Calibrate File Setup Eff Cal Calibration Standard Cs137 Status 243 8 Elapsed Real Time 241 7 Elapsed Live Time 7 202 Peak Counts C137 Coarse adjust Fine Energy Cal P sudu System Auto Adjust Device HCA2100R 001 Efficiency Cal Bias Voltage 900 Coarse Gain 8 Fine Gain 303 Delta 03x Target Actual chan chan 42 8 53 9 279 7 290 7 System Energy Calibration Linear If you need to perform a complete calibration run a Fine Energy Calibration Section 6 2 4 after com pleting the coarse adjustment 6 2 4 Fine Energy Calibration The fine e
188. system calibration may be significantly off You can also see a list of line energies associated with the BZ Sb125 Fu nuclide selected in the Isotope drop down list by clicking the Line F RS list E button 13 20 24 60 When you click on a line in this list the display will move to that 8 50 position and a blue full height line will appear in the display 7 Press the keyboard T and J keys to select lines up and down the A 1045 list 6 1778 NOTE If a line has been disabled in the Nuclide Library Use False it will not appear in this list Lines labelled in Steps 2 or 3 are not identified Those positions are simply marked in the display To identify the ROI with a particular line follow the procedure in Step 1 80 Quantum PGT PRINCETON GAMIMA TEGH 9 6 Acquiring Data The hardware must be connected and configured correctly before you can acquire data 1 Position the source in front of the detector at the normal operating position With a well detec tor place the source at the bottom of the well To calibrate the system you will need to have one or more known sources such as Cs137 or Eu152 or a mixed source which covers the energy range of interest in your work To do quan titative work you must have a calibrated standard s that covers the energy range of interest 2 Enter the desired Live Time in the Preseis tab of the hardware control panel and click Enable Presets 3 Press the Acquire button B T
189. t PPGT Procedures 83 PRINCETON GAMMA TECH 9 9 4 Efficiency Calibration An efficiency calibration must be done if you wish to do quantitative analyses QuantumGold If the previous energy and resolution calibrations were done with a calibrated standard source continue with the same spectrum Section 6 2 7 1 Inthe System Auto Calibrate panel click Efficiency Cal page 49 The display graphic now shows the spectrum with the matched lines Process Complete appears in the graphic In the scroll area the initial activity of the standard and the decay corrected activity are reported for the nuclides in the standard Added to the report in the scroll area are the efficiency data for the matched lines and the efficiency equation mix i System Auto Calibrate File Setup Eff Cal Calibration Standard Eu152 Status Elapsed Real Time Elapsed Live Time Peak Counts C137 Coarse adjust Fine Energy Cal D 9 D 6 43 9 sT 4 4 4 4 Energy A E x Channel 4 683E H8 3 869E HH 2 228 04 The efficiency data for the lines in the standard are also entered into the current Library Quantum Note After the system has been fully calibrated a daily Cs137 Coarse Adjust may be sufficient if you are certain that nothing has changed in your system The software will ask you whether the current linear or quadratic calibration should be replaced with a new linear calibration based on
190. t Radiation Measurement The external indication of a device designed to enumerate ionizing events PPGT Glossary PRINCETON GAMMA TECH Crossover Transition A gamma ray photopeak of an energy that is equal to the sum of two other energy states of a nucleus and which has a fixed probability of occurring regardless of count rate or geometry For example the 136 keV peak of Co 57 is created by de excitation of the 136 keV energy state to the ground state This energy is also obtained when the 14 keV and 122 keV peaks sum in the detector Even when cascade summing is made negligible by counting at large distances from the detector there is a probability that some de excitations will occur directly from the 136 keV energy level to the ground state Crosstalk Correction A mathematical method for correcting crosstalk effects that have been cali brated Crosstalk The number of erroneous counts in a counting channel alpha or beta in systems capable of simultaneous counting Alpha into beta crosstalk occurs when the higher energy alpha particle cre ates a smaller charge within the detector because of a non uniform detector response Beta into alpha crosstalk occurs when the beta particle backscatters into the sensitive volume creating a larger charge Data File Any file created within an application a word processing document a spreadsheet a data base file a chart and so forth Also known as document Decay Gamma A gamma ray assoc
191. the just completed coarse adjustment f you click No the existing quadratic or linear calibration will be retained With Nal detectors especially portable models used out of the laboratory if the detector warms up some peak drift may be observed This is easily taken care of with a coarse adjustment without a new quadratic energy calibration 84 Quantum 9 9 5 Calculating Detector Efficiency PRINCETON GAMMA TECH Section 6 2 8 The detector efficiency is calculated from the efficiencies stored in the current Library The equation with the appropriate constants is then stored with each spectrum collected with this detector 1 After the efficiency calibration has been completed click Eff Cal in the menu bar of the Auto Calibrate panel 2 Inthe popup click on each line to be used in the calculation and click Include i Detector Efficiency Calibration Exit Isotope Energy Intensity Efficiency Measured Calculated 2 2 n 0000 Include All Execute When you have selected all the lines to be used click Execute Close this window The following display will be seen in the Auto Calibration window and the report area will include the equation and constanis that will be included in the spectrum head ers i System Auto Calibrate File Setup Eff Cal MGS1073 System Efficiency Calibration ii Lines of 12 matched in standard H 5i1H 3 Huc lide Hn34
192. the text file you created and then saves the spectrum to that name also in the Spectra folder The same thing applies in the Analysis section Save Report asks for a file name and saves the report in the temp directory while Get Name takes the name from the designated text file and saves it to the temp directory The advantage of using Get Name rather than Save or Save Report in the script is that you can edit the text file for different jobs or samples or after each loop but still use the same Script 5 If you try to use Save Report or Get Name within a loop be aware that the report will be over written each time and at the end you will have only the report for the last analysis To get around this you can use Get Name command and then edit the name and save the text file after each loop is completed The spectrum save function for use inside loops is AutoSave which uses the 4 character pre fix with an incremented number to save each spectrum separately 6 f you use the Dead Time command in the script the dead time value can be seen by viewing the designated text tile For example you may wish to check the dead time at some time after the beginning of acquisition To do so after you enter Acquire click Interval and enter the time Then click the Presets On You can then view the text tile after that period of time and see what the dead time was at that point Although some users will just build their own applications based
193. this button changes to a stop sign You may stop and restart acquisition as often as you wish Unless you erase the data in the mem ory however restarting an acquisition will add to the data already in the mem ory rather than overwrite it Erase clears all the data and elapsed times in the primary memory If the spec trum in a live memory is erased before the preset is reached or acquisition is stopped collection will start up again immediately If you want to clear all spec trum information fields choose Edit System Parameters In the Spectrum Information panel select Clear with Spectrum Erase a em To clear all data in all memories each must be selected as primary and cleared separately When you erase a static spectrum the memory is freed You can also use the commands in the Spectrum Display and Memory Control dialog box to clear the memories see Selecting Spectrum Display and Memory Con trol Parameters on page 7 The Deconvolution display button appears if Analyze with Deconvolution m has been applied to a spectrum and the deconvolution display has been closed Click on this button to redisplay the deconvolution window The Primary spectrum info line below reports DT 02 ELT 0 00 Rate 0 0 cps 1 5tatic m Percent deadtime DT reported as differential during live acquisition and average at other times Elapsed live time ELT Count rate in cps for the primary spectrum During acquisition the
194. tility dialog box below w Qim Spectrum file import utility 010622 Incomming Spectral info Sample Desc Live Time Real Time Size Units Type Sample Date Time H Channels MOA acquire date Time ANS Type 2 Converted Spectral info Spectrum ID o Live Tmef Size 0 Units CO H Chan Real Timef Sample Datel Timef Ci Grp Size 0 Typef Ma acquire date Tmef HZ CB Oo 3 4 Save Spectrum Options Choose File Save As Spectrum to save the primary spectrum in any of the supported formats The ANS format is the only format which saves ALL of the information necessary for PGT quantitative anal ysis programs The following file formats are supported in Version 4 01 ANS Princeton Gamma Tech and American Nuclear Systems native file format Versions 1 2 3 OXS Oxford Instruments file format SPT PGT IMIX and Oxford Instruments PCA format and Gamma Trak MAS EMSA MAS Microbeam Analysis Society Version 1 1 ASC ASCII readable text OXS file format is compatible with older versions of Quantum MCA Quantum X and Oxford OASIS soft ware A single column text only output with header useful for importing spectra into Excel or another spreadsheet is supported as the ASC type The MAS file type is also readable text and includes both configuration and spectrum information 3 4 1 Save Display as Metafile Choose File Save Display as Metafile to save the entire spectrum display a
195. tion Section 7 9 If the spectrum includes an ROI for a multiplet or for overlapping lines from different nuclides the best page 73 way to resolve these peaks is with the Analyze with Deconvolution selection 1 Start with the Rapid Scan or Peak Search routine to create the ROIs Edit or delete the ROIs if needed Alternatively create the ROIs manually Expand the display to show an overlapped ROI clearly Select Analysis Tools Analyze with Deconvolution The Deconvolution display will open with the same energy range as the main display If you Deconvolution change the displayed area or range the Decon Tan volution display will change accordingly E The Gaussian peaks created by the deconvolu tion are shown in the Deconvolution display as different colored solids The original spectrum is shown in green while the reconstructed spectrum is shown in red There should be very little green in this display unless you have disabled one of the associated lines in the Library editor To eliminate an ROI from the analysis click on it either in the Deconvolution display or in the main display The Deconvolution display will show it as a white peak Then click Delete ROI and Reanalyze Note if you close the Deconvolution display an additional button vvill appear at the right in the toolbar Click this to restore the display m im onvolution results spectrum can also be examined by clicking and LI to display all s
196. trol The memory organization of the system may seem different to long term users of MCA producis In a typical MCA the user had access to a limited amount of spectrum memory The user could allocate all memory for a single spectrum or allow multiple spectra by breaking up the memory into several pieces called groups Each group contained a smaller number of channels and it was necessary to sacrifice the number of channels to get a higher number of spectra In Quantum only the live data is stored in the MCA hardware All other data is stored in the computer memory allowing the hardware to always be used at full conversion gain Up to eight spectra can be held in software memory at one time Thus the restrictions of the group concept are no longer necessary Regardless of how many specira are currently loaded most operations apply only to the primary spec trum There can be only one primary spectrum selected at any given time The primary spectrum may be selected by designating one of the memory buffers in the Spectrum Display and Memory Control dialog box or by left clicking within the spectrum s tiled mode display The primary spectrum is displayed in the primary spectrum color white in the PGT default colors All other spectra are dis played in other colors The display mode buttons on the toolbar are used to switch from multiple display mode to the primary spectrum These buttons are described in Section 2 1 HPGT Introduction
197. tructures included in file NROIs As Integer 11014 Number of ROlStructs in file RESV1016 0 To 3 As Byte 1016 Reserved for other block counters AcqSysType As Integer 110201 System type designator AcgSysLen As Integer 1022 Length of Parameter block following header New Extension File 0 To 255 As Byte 1024 File name of spectrum Library info UseLibEff As Integer 1280 Whether or not library efficiencies are used Library 0 To 11 As Byte 1282 Library associated with spectrum RESVTEMP 0 To 251 As Byte 112941 End Type Many items are used by only some applications If AcqSysLen is non zero then a secondary header block follows This block contains AcqSysLen bytes and is of type AcqSys Type No current software uses this facility so AcqSysLen should always be zero C 2 Spectrum Data Each channel of spectrum data is stored as a long 32 bit signed integer The first datum following the header is channel SpecStart The channels follow in order to channel SpecEnd Usually SpecStart is zero 0 and SpecEnd is ADCGroupsz 1 No ROI data is stored as part of the spectrum data C 3 ROI Data Each ROI is stored as a structure as defined below Type ROlIDat 50 bytes id As String 12 ROL id StrEnergy As Single ROI start energy EndEnergy As Single ROI end energy Nuclide As String 8 Associated Nuclide Element Name type As Integer Hardware Tag Integral As Double Gross Integral Centroi
198. ually from other open windows If an icon is active the Control menu appears Activity The number of nuclear transformations occurring in a given material per unit time Alpha Particle A charged particle emitted from the nucleus of an atom An alpha particle has a mass and charge equivalent to that of an ionized helium nucleus consisting of two protons and two neu trons with a double positive charge Amplification As related to radiation detection instruments the process gas electronic or both by which ionization effects are magnified to a degree suitable for their measurement Amplifier Linear A pulse amplifier in which the output pulse is proportional to an input pulse height for a given pulse shape up to the point at which the amplifier overloads Application Icon A graphic that appears only after you start an application and then minimize it Application icons are the only icons that appear on the desktop outside window borders Application Library A user created library used for analysis of routine samples and unknowns Appli cation libraries are also called user libraries or analysis libraries in our manuals Atom Smallest particle of an element which is capable of entering into a chemical reaction Atomic Mass The mass of a neutral atom of a nuclide usually expressed in atomic mass units The atomic mass unit is one twelfth the mass of an atom of C equivalent to 1 6604 x 10 gram Atomic Number Th
199. uantum PRINCETON GAMMA TEGH Select the standards and collect the data in the same way as for the fine energy calibration You can even use the same spectrum for both calibrations Click Resolution Cal to run the resolution calibra tion in System Auto Calibrate File Setup Eff Cal Calibration Standard Eut52 Status 181 7 Elapsed Real Time 180 0 Elapsed Live Time 6 185 Peak Counts C137 Coarse adjust Fine Energy Cal FWHM A SqrttEnerqy gt G Energy where A 1 178E 61 E 2 462E 00 C 2 615 E HZ Sigma of Fit 2 187 The resolution calibration data will be added to the report at the bottom of the panel 6 2 6 Resolution of Nal Systems with QCC For Nal Tl systems resolution is strongly dependent on energy At high energies peaks become very broad and the detector s efficiency drops dramatically These broad weak peaks are hard to locate and analyze At low energies the number of peaks is usually quite large and the peaks are closely spaced with reasonable resolution In the past the problem has been approached by the use of high resolution ADCs resulting in an energy per channel value small enough to give good peak resolution at the lowest energies However at the higher energies the channels are much too fine with peaks spread out over hundreds of channels When dealing with very low levels of high energy radiation these wide peaks can be very hard to detect be
200. uations from the background subtracted spectral data 2 s sY 55 Second Moment M2 where n n 26 s n Third Moment M3 The detector efficiency is calculated from the detector efficiency equation for the specific spectrum if the detector has been efficiency calibrated If not this value will be zero Once an analysis has been run if the peak has been associated with an isotope by an analytical program then the efficiency will be the efficiency for the particular line from the isotope database if the line has been efficiency cali brated 108 Quantum PP GIT PRINCETON GAMIMA TEGH In many of the analytical packages a Minimum Detectable Activity is calculated from the data in the background spectrum The exact nature of this calculation is described later The Maximum Permissi ble Activity MPA is the maximum activity in Bq acceptable for this sample This is user input and used for reporting purposes The Yield is the intensity of the line lines associated with this ROI for the nuclide specified This value is necessary to calculate the activity from the net counts 7X nt and TXAvg are two parameters used by the peak finding routine They represent the integral of the positive lobe of the convolved peak and average value of the positive lobe of the convolved peak Ewindow is a parameter which determines how well a line in the nuclide database has to match the peak center It is initialized by ROlupdate but may be su
201. uence of data in a serial communication protocol was incorrect Verify that your settings such as the number of start and stop bits the use of parity and the baud rate are correct 110 Received overrun error The system was unable to process the data as fast as it arrived You should check that your settings for flow control which allows the system to stop the flow of incoming data when it is too busy to pro cess it are appropriate The most reliable and general form of flow control is hardware flow control which requires a properly constructed serial cable If you are certain that your flow control settings are correct and you still see this message you may need to reduce the baud rate you are using for your serial communications Most modern machines will be able to work at 19200 baud under all conditions but if you have an older machine you may need to operate it at a slower speed such as 9600 baud 111 Buffer was too full to queue msg This usually indicates that your computer is trying to send commands to a device faster than the com munication protocol can transmit them For most devices and many commands this cannot occur because the command requires a reply from the device before it completes f you do see this mes sage consider increasing your baud rate 112 Device did not reply to hails A command was sent that tried to communicate with a particular device and no response was received from that device This cou
202. uisition mode In this mode the system generates a time histogram rather than an energy spectrum MCS mode is useful for experiments involving rate changes such as radioactive decay luminescence decay and chemical uptake The Pre sets panel will only show the MCS controls when MCS mode is selected Dwell Time Real Time zecs Live Time secs MCS Input lees b 500 SCA Counts Integral of all ROIs 2 50E 05 ICR Counts 1 O External Counts 0 Internal Test MES 2 Enable Presets Passes To select MCS mode e Click on the ADC2 tab Inthe OP Mode panel select MCS You cannot select MCS mode if data is currently in memory Other settings including group numbers and count inputs may be invalidated by the selection lt lt The Energy box and the Xmin Xmax boxes will display a number and caption appropriate for the horizontal MCS axis WHERE ARE THESE gt gt The default X axis units and label are always set to s and Time respectively In default mode the vertical grid is always displayed in units of seconds If you change the X axis units and label to custom values the X axis values are always in units of channels These custom values the dwell time and the MCS passes values are preserved when you close and reopen the program if the acquisition remains in MCS mode When you start an acquisition in MCS mode a trace is generated across the screen where data is acquired in each channel for the specified Dw
203. um of the unknown Make sure the Tool Setup entries either are set to the default values for the type of detector section6 6 you are using or have been further optimized for your system page 57 Select Analysis Tools Peak Search This will set ROIs of the type Unknown over all the peaks the software found Look at the spectrum If there are too many ROIs set over what is apparently just background noise go back to the Tool Setup dialog box and increase the Integral and Power as needed and run Peak Search again If there are just a few extra ROIs simply click in each of these to make it current and press the delete button Fa page 21 Similarly if obvious peaks have been missed adjust the Tool Setup entries Or manually cre ate an additional ROI over the peaks that were missed Expand the spectrum and examine the peaks Once you have optimized the Tool Setup you should be able to proceed with the rest of your analyses with little if any further adjustment 9 14 2 1 2 Peak Identify Be sure you have the correct Library for your analysis select Analysis Tools Peak Identify The report will list first those nuclides that it identified with certainty then those with some cor relation and finally list those nuclides rejected on the basis of very low correlation The last group lists the lines not matched to any library isotope If the unmatched lines include a significant peak check that peak in the display it will
204. unning your Quantum program you must establish communication between the Quantum soft ware and hardware by running the hardware search program HWSsuper exe Introduction PRINCETON GAMIMA TEGH Double click the hardware setup icon created during the installation procedure on your desktop HS super The MCA Devices Auto Configuration dialog box below left opens You must specify which hard ware you want the system to search for by selecting the appropriate options All hardware must be online and operating The program will search your system for supported MCA devices and build a device table used by the MCA Configuration Loaded from File Search Complete General Categories of Devices General Categories of Devices M Serial Port RS 485 PluainCards GPIB 4881 Ethernet USB SerialPort T RS 485 Plua in Cards GPIB 4881 Ethernet USB Specific Device Types Specific Device Types IV ANS COM M ANS COM T Tennelec PCA M Ser T Tennelec PCA M Ser Oxford nanoSPEC Oxford nanoSPEC A 7 50 00 MOD 601 002 M Quantum COM or Prospector COM 1 Baud Rate 115200 Y MOD 601 02 05 08 SN 30020 Addr 2 Unit 0 Quantum COM or Prospector COM 2 Baud Rate 19200 Quantum COM or Prospector COM 3 Baud Rate 19200 Quantum COM or Prospector COM 4 Baud Rate 19200 Quantum COM or Prospector COM 5 Baud Rate 19200 Quantum COM or Prospector CO
205. vailable ANH files The default folder is spectra To save the complete configuration from the primary memory as an ANS Header file ANH select File Save System Configuration 3 6 Background Spectrum Files To eliminate the ambient background from the sample data first collect a background spectrum with no source present Then choose File Use as Background to use this current primary spectrum as a back ground spectrum in all analytical processes The spectrum will be scaled based on the ratio of the elapsed live time to its live time and then subtracted from the current data on a channel by channel basis whenever ROI information is calculated To eliminate automatic background subtraction Choose File Clear Background OR Turn off the ambient background correction in the Setup Tool Setup dialog box If a background spectrum has been saved for the current primary memory and the current primary mem ory is not in live data acquisition select File View Background to restore the saved background as the primary spectrum PPG T File Menu 33 PRINCETON GAMMA TECH 3 7 Managing ROI Files Choose File Load ROIs to load a set of previously saved ROIs ROIs are saved in terms of energy ranges During the restore process any ROI that lies outside the energy range of the spectrum in whole or part is ignored ROIs can be restored only to an energy calibrated spectrum You can significantly increase the speed of spectrum
206. which reproduces the data of McMaster et al for all parameters except characteristic X ray lines and edges Here a more complete set of data has been used because McMaster only included five lines and nine edges The data used here includes up to 65 lines per element and all 24 edges B 2 Nal and Germanium Detectors For Nal detectors we generally model only a single window Al or Be and there is no dead layer on the detector The function used for F E is F E a b Log E c Log E d Log E There are two methods of determining the parameters available in the software When the initial coarse adjustment is done using Cs137 the following calculations are made 1 Since we have only two data points with which to evaluate several parameters we can only determine two parameters We compute the residual ratio M at each point E p dc ss c M Qe ein Fah FH 1 E Knowing the value for Mg at each energy we now have M 32 89 a b log 32 89 M 661 66 a b log 661 66 Solving for a and b vve get a fairly good approximation to the ansvver 2 VVhen vve have several standards which we can measure then we can do a least squares fit to the residual ratio using as many of the values as we desire Use the Eff Cal menu on the Auto Calibrate screen to calculate the fitted curve and display the resulis HpGT PGT File Structure 115 PRINCETON GAMMA TEGH Appendix C PGT File Structure
207. y Spectrum Display Options 35 4 2 Edit System Parameters 35 4 3 Edit Screen Annotations 36 4 4 Nuclear Library Editor 37 4 4 1 Library Editor Features 37 4 4 2 Nuclear Library Editor Menu Options 39 5 View Menu Options 40 5 1 Display Offsets 40 5 2 Spectrum and System Setups 41 5 3 ROL Toolbar Display 41 6 Setup Menu 42 6 1 About System Calibration 42 6 2 Automatic Calibration 42 6 2 1 Calibration Setup 43 6 2 2 Creating and Editing a Calibration Standard 44 6 2 3 Coarse Adiustment 45 6 2 4 Fine Energy Calibration 46 6 2 5 Resolution Calibration 47 6 2 6 Resolution of Nal Systems with QCC 48 6 2 7 Efficiency Calibration 49 6 2 8 Efficiency Curve 50 6 3 Manual Calibration 52 6 3 1 Manual Two Point Energy Calibration 52 6 3 2 Manual Energy Calibration by ROI Centroids
208. y informa tion to the default startup files you may need this information to restore the configuration for both the MCA and other analytical parameters The controls follow a few general conventions PPGT Main Display PRINCETON GAMMA TECH e You can enter new values directly into fields with a white background If the value is outside the acceptable range for the device or does not correspond to an actual setting the nearest actual setting will be selected and displayed e Fields with a gray background show existing values You cannot enter data directly into them e When a spin box is present next to either type of field you can increase or decrease the value in the field by its smallest supported increment In general fields that have more than ten or twenty possible values provide both the ability to enter a number and the ability to adjust it using the spin box e Some fields only provide feedback about the current state of the device They are gray and do not have a spin control Because the contents of the panels are dependent on the system hardware configuration the panels shown below which show all the possible controls will look slightly different than the panels on your system 2 3 1 Preamplifier and Bias Controls Preamp Type Preamp Mode Alarms Bias Voltage Enable Status Auto C Trans reset Single Ended Shutdown 2 Enable or Pulsed optical R Ext Input 7 External
209. y names indicates that the keys should be held down at the same time CTRL is also known as the Control key ANS Filenames and extensions are shown in bold capital letters Brovvse Names of command buttons option buttons tabs panels and dialog boxes are shown in bold mixed case 1 2 Recommended Hardware Configuration The Quantum programs operate on Pentium or higher Intel based personal computers with 16 536 color XVGA 1024x768 or higher resolution graphics operating in small fonts mode The minimum system requirements are Pentium processor 32 MB RAM e 8 MB free disk space e 16 megabyte swap file The recommended system requirements are Pentium l 300 MHz or Celeron 333 MHz processor e 64 MB RAM Quantum HapGT PRINCETON GAMMA TEGH FAST Hard Disk e XVGA Windows Accelerated Video at 1280x1024 with 16 536 colors in small fonts mode Quantum Note All producis have been tested and found to function properly under Windows 95 Windows 98 Windows 98SE Windows NT4 Windows 2000 and Windows Me 1 3 Installation The basic software package comes on a CD Before installing the software install any PGT hardware in your system At the time of software instal lation all hardware should already be online Insert the CD into the CD ROM drive README TXT files and other document or PDF files are located in various folders on the CD Select Run from the Start menu Enter F SetupQtmXXX402 exe where

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