Optimization of the gamma-ray spectrometry counting time based on uncertainties of radionuclides concentration in samples

Abstract

This paper aims to propose an easy and fast method of optimization of the gamma-ray spectrometry counting time in determining natural radionuclides (Pb-210, Pb-212, Pb-214, Bi-212, Bi-214 and Ac-228) in order to minimize uncertainties in the concentration. The samples were measured by gamma-ray spectrometry with a hyper-pure germanium detector Canberra, 25% relative efficiency, effective resolution of 1.9 keV on the 1332.5 keV 60Co with associated electronics and coupled to a microcomputer. Multichannel Maestro A65-I model was used for spectrum acquisition and peak net area determination, and WinnerGamma/Interwinner 6.01 software was used for gamma-ray spectra analysis and to calculate the concentrations and associated uncertainties.  The counting times used were 86,000 s and 150,000 s.