Monte Carlo simulation of photo-peak efficiency response function and calculation of total efficiency for a NaI (Tl) scintillator detector

Abstract NaI (Tl) scintillation detectors are widely used in laboratories and in the field of gamma-ray spectrometry where detector efficiency is a key factor for successful quantitative γ ray analysis. In this work, Monte Carlo simulations using MCNPX code have been performed in order to evaluate energy resolution as a full width at half maximum (FWHM) of the peak and absolute efficiency of NaI detectors. Also, the detection efficiency and energy resolution for the NaI (Tl) scintillation detector of Tehran Research Reactor (TRR) pollution monitoring laboratory was measured. Simulation results were compared to experimental data and good agreement are obtained. In radioactive analyzing laboratory, precise determination of the detector efficiency according to any different gamma energy is a very important parameter whereas it uses in daily laboratory work.