Development of B and BN thin films for in situ neutron beam monitoring

Abstract

A B-based thin-film neutron monitor is developed for the in situ neutron beam monitoring of the Korea Atomic Energy Research Institute neutron depth profiling system. Thin-film samples are prepared via radio-frequency (RF) sputtering. The RF power, Ar partial pressure, and deposition temperature are varied to optimize the growth and thickness uniformity of the samples. The neutron transmission ratio and collision heating of the designed samples are estimated via Monte Carlo simulation. The neutron transmission ratios of B and BN films prepared in this study are 92.46% and 93.93%, respectively, and the effect of temperature increase is negligible. The displacement per atom (DPA) rates of the B and BN thin films are lower than those of other known B neutron flux monitors, based on the results of DPA calculation for estimating the defect of the sample via neutron irradiation.