Monte Carlo sampling for gamma and beta detectors using a general purpose PC program

Abstract

The main objective of this study is the computation of several parameters involved in gamma and beta environmental radiation measurements, such as detection efficiency, the attenuation coefficients, mass energy-transfer coefficients and mass energy-absorption coefficients for several materials. In order to accomplish these tasks we developed a PC program, based on a Monte Carlo simulation of radiation transport. This program (GES_MC Gamma-electron Efficiency Simulator) was written entirely in Java and was based on the EGSnrc (Electron Gamma Shower) source code. Although GES_MC was especially designed for the computation of the response function and peak efficiency for gamma detectors, it can also be used in various studies concerning photon or electron interactions with the matter in any cylindrical (RZ) geometry. Several aspects of photon and electron transport and the comparison of the program outputs with experimental data are also presented in this study. The main advantage of the Monte Carlo simulations presented in this paper is that any source and any detector can be properly sampled. In contrast with the Monte Carlo technique, for an accurate experimental result, the computation of detector efficiency for a large number of standard sources having various geometries and compositions is required (one standard source for each sample type).