Coincidence summing of X- and gamma rays of 75Se

A study of coincidence summing of X- and gamma rays of 75Se has been presented in this paper. The computation of the 75Se spectra was performed by application of the previously published theory by Novković et al. The method enables the treatment of all possible single and sum peaks of 75Se. 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.

► The theory developed by Novković et. al. was applied to the decay of the 75Se. ► The method enables the treatment of all possible single and sum peaks of 75Se. ► The model takes into consideration the existence of metastable level. ► The 75Se spectra are measured by means of two HPGe spectrometers. ► Agreement between the theory and experiments confirms the literature decay scheme data.