Registration and identification of low γ-activities: the optimal way of processing measurement data

The detection and identification of low-active nuclide pollutions on the base of the measured spectrum of signals can be carried out either by counting γ-photons within a narrow energy window in the vicinity of a proper complete absorption line or with the use of the entire spectrum of signals (including the Compton continuum). To optimize the processing of the measured spectrum of signals, the minimal detectable activities (MDA), corresponding to these ways of processing, are calculated and compared. It was found that the latter way has an essential advantage: it provides a smaller value of MDA and, unlike the former way, is efficient for a mixture of nuclides with overlapping lines of complete absorption.