Efficiencies and photofractions of some commonly used NaI(TI) well crystals

Abstract

A knowledge of the ratio of the number of gamma rays that are completely absorbed in the crystal to the total number of gamma rays that interact at least once is necessary in evaluating a detector for applications involving selective pulse-height analysis. A calculation of this ratio, called the photofraction, p(E), is complicated by the variable source volumes encountered in practice, and, as a result, an empirical study of p(E) as a function of crystal and sample geometry was made for four different scintillation spectrometers. (auth)