Patent ID: 6492642
Filing Date: 2002-12-10
Classification: G01T

Abstract:
A method for identifying radionuclides in samples with the use of a liquid scintillation counter, comprisingselecting a sample of the environment or a technological sample, preparing the sample for measurement on a liquid scintillation counter, measuring and recording the spectrum of the sample, grouping the measured spectrum of the sample, creating a model spectrum on the basis of a library of base spectra of radionuclides, determining the content of radionuclides in the sample by minimizing the deviation of the model spectrum from the measured spectrum of the sample, characterized in that determination of the content of radionuclides in the sample by minimizing the deviation of the model spectrum from the measured spectrum is carried out according to the expression &Sum;i&it;(Pi-Mimin(Pi,Mi+Î´)2->min,where Pi is the measured spectrum of the sample,&dgr; is a coefficient, on the value of which the stability of the minimization process depends (&dgr;>0), Mi=&Sum;j&it;cj&it;Miji is the number of a group, j is the index of a radionuclide, Mij designates normalized spectra of separate radionuclides from the library of base spectra, cj designates relative contributions of base spectra of radionuclides to a model spectrum, by varying the values of these contributions cj, after which the obtained values of relative contributions of base spectra of radionuclides cj are recalculated into values of absolute activities (Aj) of radionuclides in a sample according to the equation: Aj=cj*P/Ej where P=&Sum;i&it;Piis the integral count of the sample,Ej is the efficiency of registration for the j isotope.