Simulation of a NaI(Tl) detector model using OpenMC modified on code source and validation using experimental and simulated results

In order to expand and examine the capabilities of the OpenMC Monte Carlo code to characterize the response function of the gamma radiation detectors (since OpenMC does not support this simulation), this paper presents the methodology used to modify the OpenMC code source and to characterize the response function of a NaI(Tl) scintillation detector. In addition, it includes a characterization of the response function for the 1.5"x 2"NaI(Tl) scintillator detector using various Monte Carlo codes. Finally, a comparison between the experimental data and the results obtained with OpenMC modified on code source, MCNP, and Geant4 models is presented. The detector efficiency and energy resolution were calculated over the photon energy ranging of 59-662 keV by using a precise model, which was developed by using the previous codes. The validation of the OpenMC model has been accomplished by a comparison of the results with the Monte Carlo Geant4 and MCNP models results, and experimental data, which shows a good agreement. This validation confirms that the modified OpenMC model can be successfully implanted in the modeling of the response functions of the NaI(Tl) scintillation detectors.