Study of digital pulse shape discrimination method for n-{\gamma} separation of EJ-301 liquid scintillation detector

TL;DR

This paper develops and tests a digital pulse shape discrimination system for liquid scintillation detectors, demonstrating effective neutron-gamma separation using two algorithms and analyzing detector performance at various energy thresholds.

Contribution

It introduces a digital pulse shape discrimination system with algorithms for n-γ separation, showing improved performance over traditional methods.

Findings

Zero-crossing method outperforms at low energies

Charge comparison method performs better at high thresholds

Smaller detector has superior n-γ separation for fission neutrons

Abstract

A digital pulse shape discrimination system based on a programmable module NI-5772 has been established and tested with EJ-301 liquid scintillation detector. The module was operated by means of running programs developed in LabVIEW with the sampling frequency up to 1.6GS/s. Standard gamma sources 22Na, 137Cs and 60Co were used to calibrate the EJ-301 liquid scintillation detector, and the gamma response function has been obtained. Digital algorithms for charge comparison method and zero-crossing method have been developed. The experimental results showed that both digital signal processing (DSP) algorithms could discriminate neutrons from gamma-rays. Moreover, the zero-crossing method shows better n-{\gamma} discrimination at 80 keVee and lower, whereas the charge comparison method gives better results at higher thresholds. In addition, the figure-of-merit (FOM) of two different dimension detectors were extracted at 9 energy thresholds, and it was found that the smaller one presented a better n-{\gamma} separation property for fission neutrons.