Comparison of two spectrometric counting modes for fast analysis of selected radionuclides activity

Abstract

The two counting modes: a normal with a single HPGE detector and second with the additional anti-Compton shield of the annular NaI(Tl) detector have been compared for fast determination of the activity concentration of thorium 232Th in the building materials. The 232Th activity concentration was calculated by measurement of its decay products: 212Pb, 212Bi and 208Tl as well 228Ac content. Although the Compton suppression mode applied in gamma spectrometry systems in general increase sensitivity of the analysis, but in case of 583 keV the most abundant 208Tl γ-line, the significant reduction of photon counting rate was observed.