Comparison of gamma-ray efficiency on various standard sources of environmental radioactivity of HPGe detectors using the Monte Carlo method (MCNP5).

A comparison of the gamma ray efficiency of various standard sources of environmental radioactivity was carried out for the two types of HPGe detectors. This study aims to compare the efficiency curves of standard gamma-emitting radionuclides from experiments in the field with Monte Carlo simulations in an easy and precise way for testing various types of environmental samples with different sample densities and geometries. Standard sources used include Epoxy, Sand, RGU-1, and RGK-1. Gamma ray efficiency measurements and calculations were carried out using the Monte Carlo simulation method, namely MCNP5 by reviewing two main parameters, including the influence of dead layer geometry and germanium crystals and matrix density. The results showed that the best agreement between experimental and simulation result for gamma ray efficiency value was achieved at low energy (< 90 keV) for Canberra HPGe detector, while for the Ortec HPGe detector was achieved at high energy. The gamma-emitting radionuclides from different types of environmental samples can be analyzed properly by following those criteria. [ABSTRACT FROM AUTHOR]