GammaVision
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v7 (A66-BW) 783620H / 1013
6.17.5.3. The Best Estimated Activity
The best estimate of the net peak area, N
h
, is discussed in Eq. 33 and F.20 in ISO NORM. It is calculated as:
(183)
where Q is defined as:
(184)
and the parameter
ω is defined as follows (see Eq. 31 or F.18 in ISO NORM):
(185)
The integration is from
!4 to Q. In Eq. 183, the second term comes from the biased estimator used in ISO NORM.
Conversion from the above best estimated peak area to the best estimated peak activity is done through Eq. 149.
The uncertainty of the best estimated net peak area counts, based on Eq. 34 in ISO NORM, is:
(186)
where all quantities have been defined before. From Eq. 183, because the best estimated peak area N
h
is always greater than the net peak area N, the uncertainty of the best estimated peak area is always less than the uncertainty of the net peak area. If this value is zero, it is set to the best estimated net peak area.
If the isotope activity is zero or negative, and if the best estimated activity is more than three times the uncertainty of the best estimated activity, the best estimated activity and the associated uncertainty are set to zero.
6.17.5.4. The Lower and Upper Limits of the Activity
From ISO NORM Eq. 29, the lower limit of the peak area is:
322
