NEW SOFTWARE FOR ANALYZING COMPLEX SPECTRA OBTAINED WITH ULTRA LOW LEVEL LIQUID SCINTILLATION SPECTROMETER ̀ QUANTULUS'

ABSTRACT. A new Windows-based program for analyzing the complex beta spectra measured with an ultra low-level liquid scintillation spectrometer "Quantulus " was developed. The program utilizes the method of fitting the spectrum obtained via LS-counting by the spectra of individual radionuclides presented in a library of spectra created prior to the experiment. It also relies on a characteristic spectrum shape in the "Quantulus " logarithmic amplification mode. The method allows the analysis of multi-label samples containing up to six (and in certain cases even more) radionuclides presented at various activity levels. For example, the radionuclide activities were successfully determined in the following complex mixtures: 3H, 63Ni, 35S, 60Co, 90Sr+90Y, and 137Cs with the activity ratio of the same order of magnitude, as well as 3H/89Sr/137Cs/90Sr+90Y with the activity ratios 100:50:10:1 and an uncertainty of about 15%. The restrictions of the developed program are considered