Summing coincidence in rare event gamma-ray measurements under an ultra-low background environment

TL;DR

This paper introduces a Monte Carlo simulation approach using GEANT4 to correct and improve the efficiency measurements of gamma-ray detectors in ultra-low background environments, accounting for summing coincidences.

Contribution

It presents a novel Monte Carlo method for correcting detector efficiencies by incorporating true summing coincidence factors, enhancing accuracy in gamma-ray measurements.

Findings

Efficiency improvements up to 18% after correction.

Summing coincidence peaks can be accurately reproduced within 3%.

Method applicable to various isotopes like $^{60}$Co, $^{133}$Ba, and $^{152}$Eu.

Abstract

A Monte Carlo method based on the GEANT4 toolkit has been developed to correct the full-energy peak (FEP) efficiencies of a high purity germanium (HPGe) detector equipped with a low background shielding system, and moreover evaluated using summing peaks in a numerical way. It is found that the FEP efficiencies of $^{60}$Co, $^{133}$Ba and $^{152}$Eu can be improved up to 18\% by taking the calculated true summing \mbox{coincidence} factors (TSCFs) correction into account. Counts of summing coincidence $\gamma$ peaks in the spectrum of $^{152}$Eu can be well reproduced using the corrected efficiency curve within an accuracy of 3\%.