A STATISTICAL MODEL OF GAMMA-SPECTROMETER OUTPUT FOR MULTI-RADIONUCLIDE SAMPLES CONTAINING VARIOUS RADIONUCLIDES
A.G. Vostretsov1,2, S.G. Filatova1,3, S.P. Shaparev1,4
1Novosibirsk State Technical University, Novosibirsk, Russia
2N.A. Chinakal Institute of Mining Engineering, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
3Federal Institute of Industrial Property, Moscow, Russia
4Scientific-production enterprise of geophysical equipment «LOOCH», Novosibirsk, Russia
Keywords: gamma spectrum, gamma radiation, radionuclide, gamma spectrometry, Poisson flow
Abstract
A statistical model of the gamma spectrum at the output of a spectrometer with a scintillation detector has been proposed for the spectrometry of a sample containing a large number of different radionuclides. The model is based on representing the observed number of pulses at the output channels of the gamma spectrometer with a scintillation detector during the exposure time as an ordinary stationary Poisson integer process. It takes into account that the energy spectrum of gamma quanta at the detector input is a superposition of the spectra of each radionuclide in the sample, as well as background radiation.The shape of the gamma spectrum of the background and each radionuclide is defined by a corresponding normalized vector, while its intensity is determined by the total area of the radionuclide's spectrogram. An analytical expression for the probability density of the total gamma spectrum has been derived. A synthesized algorithm for estimating the areas of the components of the total gamma spectrum, based on the proposed model, is presented. Using the example of analyzing a sample containing three radionuclides (60Co, 152Eu, and a background with 137Cs backlighting), the high efficiency of the algorithm is demonstrated through computer simulation.
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