Pulse shape discrimination in the plastic scintillator EJ-299-33

New advances in plastic scintillation compositions have opened the field to new, exciting instruments capable of neutron-gamma ray pulse shape discrimination (PSD). We present PSD figure of merit parameters and neutron time-of-flight from Cf-252 using a 5.08-cm diameter by 5.08-cm thick sample of PSD-capable plastic scintillator EJ-299-33 and compare these results to those from a same-sized EJ-309 liquid scintillator detector. An offline, digital PSD method was applied to both detectors. The results show that EJ-299-33 plastic PSD is very good, having a figure of merit of approximately 0.9 for 120 keVee threshold; however the EJ-309 liquid scintillator PSD is superior to the EJ-299-33 plastic scintillator PSD, with a figure of merit of 1.5 at the same measurement threshold. We also found that the EJ-299-33 has reduced neutron detection efficiency compared to the EJ-309. For the fission neutron spectrum measured here, the ratio of the plastic to liquid total number of measured neutrons was approximately 0.63.