Evaluation of gamma-ray spectrometric results near the decision threshold

A computerized procedure for analyzing high-resolution gamma-ray spectra was improved in three regards: the peak areas having large relative uncertainties were corrected for the possible contribution of statistical fluctuations in the continuous background, the peaks having a negative net peak area after background subtraction were included in the activity calculations and the primary measurement results were converted to the best estimate using an application of the Bayes theorem. It was proven empirically that the improvements that were introduced diminish the probability and severity of type-I errors and that they improve the consistency and accuracy of the measurement results near the decision threshold.

► Peak areas having a large relative uncertainty were evaluated. ► The activities corresponding to peaks with a negative net count rate were assessed. ► The Bayes theorem was used to convert observed values to best estimates. ► Radionuclide activities near the decision threshold were estimated. ► The frequency of type-I errors was determined empirically. ► The consistency and accuracy of measurement results was evaluated.