Toward utilization of MCNP5 particle track output file for simulation problems in photon spectrometry

Abstract

Pulse height distribution (PHD) registered by a spectrometer is influenced by various physical phenomena such as photon interactions as well as disturbance produced by the electronic circuits inside the spectrometer. Therefore, spectrometry measurements of gamma and X-ray radiation inaccurately represent primary spectra. In order to overcome spectrum disruption, spectrum unfolding has to be applied. One of the common tools used in the unfolding process is Monte Carlo simulation of spectrometer response to monochromatic photons. The purpose of this work is to develop a new method for simulating CdTe semiconductor spectrometer response to monochromatic photons that can be further used for the spectrum unfolding procedure. The method is based upon post-processing of the particle track (PTRAC) output file generated by the MCNP5 program. In addition to the spectrometry output, this method provides information for each specific photon interaction inside the spectrometer active volume, which is required when taking into account spectrometer charge collection. The PTRAC generated detector response and the measured spectrum were in good agreement. The results obtained showed that this method can be used to generate precise response functions of gamma and X-ray spectrometers.