Determination of practical energy range for SiPM-based pulse shape discrimination using Time-of-Flight

Abstract

The importance of fast neutron detection is emphasized in aspects such as special nuclear material (SNM) detection and nuclear non-proliferation. Since most of fast neutron detecting environments involve gamma-rays, precise separation of fast neutrons is required. In such mixed fields, Pulse Shape Discrimination (PSD) is applied to discriminate neutrons and gamma-rays. While PSD is effective for discriminating neutrons and gamma-rays in relatively high energy regions, there is an overlap between the distributions of the two in low energy region. Eventually, to make full use of low energy neutrons, the distribution originating from high energy region should be applied to low energy region as well, which is a limitation. Neutron Time-of-Flight(n_ToF) is one of the most certain method to resolve this kind of uncertainty. Meanwhile, silicon photomultiplier (SiPM)s come to the fore as an alternative that can supersede conventional photomultiplier tube (PMT)s in radiation detection. In this thesis, determination of practical energy range for PSD is covered, where two-Gaussian distribution from high energy region can be applied, by using n_ToF method.