Simulation of gamma reference field at Institute for Nuclear Science and Technology using Monte Carlo method

Abstract

This paper presents the characterization of two gamma reference fields of ¹³⁷Cs and ⁶⁰Co sources at the Institute for Nuclear Science and Technology. The characterization of the fields in terms of gamma fluence Փ, mean energy, E_Փ, kerma weighted mean energies, E_K , air kerma, E_air,  were determined at various distances from the source center by Monte Carlo simulation using MCNP6. The air kerma results were compared with the measurements obtained by using a calibrated ionization chamber. The discrepancy between the simulated and measured air kerma was less than 4.5%. The scatterred component was also simulated and calculated. The results of both methods showed that the contribution of the scattered components to the gamma reference field is less than 3%. This contribution comply with the international standard criteria of ISO 4037 (<5%). The results confirmed that the characterization of the gamma reference field could be determined using the simulation code.