Neutron/gamma pulse discrimination analysis of GS10 lithium glass and EJ-204 plastic scintillators

Abstract

Two radiation sensitive scintillators known for their dual sensitivity to neutron and gamma-ray fields are investigated for their pulse discrimination abilities; a lithium glass GS10 inorganic scintillator and a fast organic plastic scintillator EJ-204. Each of these scintillators are optically coupled with an 8 × 8-silicon photomultiplier array to act as a photodetector. Pulse height analysis, the charge comparison method and pulse gradient analysis have all been applied here on neutron and gamma-ray events generated by a Cf-252 source. The three discrimination methods were evaluated based on the figure of merit of the probability density plots generated. Within a GS10 crystal, it has been deduced that pulse height analysis and pulse gradient analysis possess greater abilities to discriminate between the two radiation fields compared to the charge comparison method with both showing a figure of merit of over one. The charge comparison method indicated a lower discrimination ability with a figure of merit around 0.3. When the EJ-204 detector was used, it was deduced that only pulse height analysis exhibits discrimination abilities with a figure of merit around 0.6, while the other two discrimination methods presented no distinction between the two radiation fields.