GammaVision
®
v7 (A66-BW) 783620H / 1013
(59)
where:
A
Ei
= the activity of nuclide i based on energy E
N
Ei
= net peak area for peak at energy E
TDC
= decay corrections, incorporating DDA, DC, and DDC as defined in
Sections 6.10.1 through 6.10.3.
Mult
= multiplier entered on the System tab.
RSF
= random summing correction factor (Section 6.11).
LT
ε
E
= live time.
= detector efficiency at energy E (Section 5.3.3); this efficiency factor is stored in the
.CLB
record of the
.SPC
spectrum file.
Br
= peak branching ratio from library.
GeoFac = geometry correction factor as described in Section 6.10.5.
A c
Div s
= attenuation correction (Section 6.10.6.1).
= divisor entered on the System tab.
= sample quantity entered on the System tab.
This “peak activity” is reported in the nuclide peak matrix (if requested). If there is more than one peak in the energy analysis range for a nuclide, then an attempt to average the peak activities is made. The result of the average is the average nuclide activity.
6.7.1. Average Activity
The average activity for the nuclide is calculated by first calculating a gammas/disintegration weighted average of the first and second library peak activity, if the activity of the second peak is within N times the uncertainty of the first peak activity, where N is the Activity range factor in b30winds.ini
(Section A.2.2, page 445; the default value is 2) if the activity of the second peak is within two times the uncertainty of the first peak activity. Only peaks that (1) do not have the “Not in Average” flag set and (2) have been positively identified per the criteria in
Section 6.7 (and their associated branching ratios) are included in this summation.
The uncertainty in the first peak activity includes counting uncertainty of the first peak, uncertainty in the library entries, and uncertainty in the calibration. Subsequent peaks are likewise included in a running average if their activity is within two times the uncertainty of the running average activity. The averaged activity is weighted by the branching ratio and is calculated as:
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