NISTI, M.B.MADUAR, M.F.SAUEIA, C.H.R.CAVALCANTE, F.MAZZILLI, B.P.2020-10-082020-10-082020NISTI, M.B.; MADUAR, M.F.; SAUEIA, C.H.R.; CAVALCANTE, F.; MAZZILLI, B.P. Optimization of the gamma-ray spectrometry counting time based on uncertainties of radionuclides concentration in samples. <b>Brazilian Journal of Radiation Sciences</b>, v. 8, n. 2, p. 1-12, 2020. DOI: <a href="https://dx.doi.org/10.15392/bjrs.v8i2.1197">10.15392/bjrs.v8i2.1197</a>. Disponível em: http://repositorio.ipen.br/handle/123456789/31418.2319-0612http://repositorio.ipen.br/handle/123456789/31418This paper aims to propose an easy and fast method of optimization of the gamma-ray spectrometry counting time in determining natural radionuclides (210Pb, 212Pb, 214Pb, 212Bi, 214Bi and 228Ac) 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.1-12openAccessactinium 228bismuth 212bismuth 214cobalt 60counting techniquesdata covariancesgamma spectroscopyhigh-purity ge detectorslead 210lead 212lead 214multi-channel analyzersoptimizationArtigo de periódico2810.15392/bjrs.v8i2.11970000-0001-7174-9703https://orcid.org/0000-0001-7174-9703https://orcid.org/0000-0002-4448-003XSem Percentil