Neutron and Gamma Ray Pulse Shape Discrimination with EJ-270 Lithium-Loaded Plastic Scintillator

Abstract

The new EJ-270 plastic scintillator developed by Eljen contains the element lithium at an isotopic enrichment of 95.5 atomic percent of lithium-6. This material is based on research carried out at Lawrence Livermore National Laboratory where the scintillator was developed. The material is formulated to provide Pulse Shape Discrimination (PSD) of scintillation pulses from thermal neutrons, fast neutrons and gamma rays. Pulse shape discrimination measurements and analysis are made on an early EJ-270 sample measuring 51 x 51 mm (diameter x length) with a lithium-6 loading level of 0.5% by weight. Results are presented on the PSD separation that can be achieved between the three radiation detection modes. Also, direct comparisons of neutron/gamma separation and neutron detection efficiency are made with the Eljen EJ-299-33 PSDcapable plastic material.