Coincidence summing of X- and gamma rays of Se-75

A study of coincidence summing of X- and gamma rays of Se-75 has been presented in this paper. The computation of the Se-75 spectra was performed by application of the previously published theory by Novkovi et al. The method enables the treatment of all possible single and sum peaks of Se-75. The calculation gave the 419 decay path outcomes, resulting in 84 peak count rate equations and also the total count rate equation. By HPGe spectrometers with 15% and 18% relative efficiency, 20 and 30 peaks were recorded, respectively. Some simplification of the decay scheme was introduced and existing metastable level had to be treated separately. Nevertheless, the experimental values of the peak count rates were in good agreement with the theoretical evaluation. (C) 2011 Elsevier Ltd. All rights reserved