GammaVision
®
v7 (A66-BW) 783620H / 1013
CorrectionFactor is the product of the calibration efficiency at the specified peak energy and the peak’s branching ratio (yield) as listed in the working (active) library.
To add an MDA preset, enter the preset value in the MDA or Corre-
ction field; select the Nuclide and
Energy; enter the desired values for coefficients a, b, and c; then click Add New.
To edit an existing preset, click to highlight it in the table. This will load its Nuclide, Energy, and coefficients in the lower sections of the dialog. Change as needed, then click Update.
Fig. 86. DSPEC-50 MDA Preset Tab.
To remove a preset, click to highlight it in the table, then click Delete.
IMPORTANT
These MDA presets are not dynamically calculated. Each time you add an
MDA preset to this table, its CorrectionFactor value is calculated and stored in the MCB’s memory. If you then load a different library, change the efficiency calibration, or change the system geometry, the spectroscopy application will
not update the existing CorrectionFactors, and your MDA presets may no longer be applicable.
Nuclide Report Tab
Figure 87 shows the Nuclide Report tab. The Nuclide Report displays the activity of up to nine
(9) user-selected peaks. Once the report is set up, the two lowest-energy ROIs and their respective activity readouts are displayed on the DSPEC-50's Spectrum screen.
The peak area calculations in the hardware use the same methods as the Peak Info calculation
(Section 5.4.3) so the Nuclide Report display is the same as the Peak Info display on the selected peak in the spectra stored in the PC. The calculated value is computed by multiplying the net peak count rate by a user-defined constant. If the constant includes the efficiency and branching ratio, the displayed value is the activity. You enter the nuclide label and the activity units. The report format and calculations are discussed in the next section.
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783620H / 1013 5. MENU COMMANDS
IMPORTANT
The entries you make on this screen are saved in the MCB memory, and are not
dynamically calculated. If you change the energy calibration (i.e., if the peak locations shift), the Nuclide Report may no longer be valid.
Add New
You can add Nuclide Peaks to the report manually or by selecting the peaks from the current working library. The spectrum must be energy calibrated to use the library method.
! Defining Peaks Manually
— To manually define peaks, enter the Nuclide name, ROI
Low (start) and High (end) channels, multiplicative Fac-
tor and Units in the Report section; then click Add New.
Fig. 87. Nuclide Report Tab.
All nuclides in the table use the same units, so that value need only be entered once.
! Selecting Peaks from the Working Library — To define report peaks using the library, select the Nuclide and gamma-ray Energy in the Library section. This defines which gamma ray to use. Now, in the Report section, click the Select from Lib button. Enter the
Factor and Units, then click Add New to add this nuclide to the list. The ROI for this peak will be marked in the MCB’s spectrum window, centered on the peak energy and
3 times the width of the calibrated FWHM.
Edit
To change any of the current nuclides, select the nuclide in the list (use the scroll bars if needed).
This will show the current settings for this nuclide. Make any changes needed. Any or all of the entries can be changed. When finished with the changes, click on Update.
Delete
To remove an entry, select the entry and click Delete.
When you close the Properties dialog, all the values entered are written to the DSPEC-50 and the two lowest-energy ROIs and corresponding activity readouts are displayed on the DSPEC-50 screen.
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