Optimization of PSD for Stilbene as a Function of Neutron Energy Deposition

This work proposes that the optimal tail-integral start time in the digital-charge integration technique for pulse shape discrimination (PSD) changes as a function of energy deposition in a scintillator. A stilbene scintillator coupled to a photo-multiplier tube (PMT), was used to detect gamma rays and neutrons from a californium-252 spontaneous-fission source. A data acquisition system with 14-bit vertical resolution across a 2 V dynamic range and a sampling rate of 500 MHz was used to digitize pulses from the PMT. Using figure-of-merit (FOM) studies that quantify PSD performance, the optimal tail-integral start time was calculated as a function of neutron-energy deposition.