A comparison of four different digital algorithms for pulse-shape discrimination in fast scintillators

A comparison of four algorithms for the digital discrimination of neutrons and γ ‐ rays in organic scintillation detectors is described. The mixed fields from four different isotopic neutron sources have been investigated with a fast digital processing system. This system has been used to digitise the raw sampled data for each individual pulse collected for each of the mixed radiation fields. The discrimination methods considered are the digital Charge Comparison Method, Pulse Gradient Analysis, Neutron– γ Model Analysis and Simplified Digital Charge Collection. The ratio of the number of γ ‐ ray counts to the number of neutron counts, often referred to as the R-factor, has been calculated for each mixed radiation field. These provide a basis for reference where future R-factor analysis of isotopic sources is to be carried out for the purposes of calibrating discrimination systems or when estimating the γ ‐ ray rejection effectiveness of neutron detector systems based on fast liquid scintillators. The efficacy of each of these methods has been assessed in terms of the figure-of-merit (based on the separation of the event distributions). The SDCC technique is observed to provide the best discrimination performance in this research.