1. Radionuclides of Interest
Select primary (parent) radionuclides of interest by clicking on a radionuclide in the
"Radionuclides (and daughter progeny)" list to highlight it and then click
on the ">>" button to add it to the "Radionuclides of Interest"
list. To calculate the parent and daughter activities manually,
deselect the box "Include daughter products." When one or all radionuclides have been selected, click "Next".
2. Activity Concentrations
Enter the target activity concentration (TAC) in pCi/cm2 for each radionuclide in the table.
TACs are like PRGs. If multiple radionuclides are selected, enter the Field Activity Concentrations (FACs).
FACs are simply used to generate the isotopic ratio. Click "Next".
3. Detector & Site Information
Select the size of the gamma scintillation detector. Enter the estimated distance between the source and the detector in
centimeters. Click "Next".
4. Results
The results are displayed. In the
"Number of Photons" column, click on the hyperlinked number for a list
of a radionuclide's photon energies and yields. The GDR is presented in
bold. GDR is the instrument reading that must be achieved in order to
meet the Target Activity. Click the "Back" button to go back a page or click "Start Over" to begin another calculation.
A Field or Target Activity (CPM) result of
"-" indicates that no photons are generated by the radionuclide's decay chain and thus cannot be detected by a gamma scintillation detector. Radionuclides with 0 photons do not contribute to the total GDR. This tool only works for gamma emitters.
If a radionuclide in the list emits one or
more photons outside the range of the detector, a note will appear below
the results table notifying the user that the selected spectrum has
photons outside the range of the detector. A list of the photons
excluded from the calculation of Gross Detector Response (GDR) will
appear on the "Photons" page which can be accessed by clicking on the
hyperlinked number of photons of a radionuclide.
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