Pulse Shape Discrimination Properties of Neutron-Sensitive Organic Scintillators

The new plastic scintillators with n/γ pulse shape discrimination (PSD) properties being developed by the Lawrence Livermore National Laboratory (LLNL) and commercialized by Eljen Technology are addressing the toxicity and flammability issues of liquid scintillators, thus enabling a much wider range of practical applications for the detection of neutrons. These scintillation materials use multiple dyes, the concentration of which can vary, and therefore the light output and PSD properties of these new materials are expected to vary as well. In this paper, we compare the light signal time profiles of a liquid scintillator and two samples (one from LLNL and one from Eljen Technology) of new plastic scintillators with PSD properties. We acquired the light signal time profiles using both γ sources (⁶⁰Co, ¹³⁷Cs, ²⁴¹Am) and neutrons calibrated in electron-equivalent by the gamma sources. The n/γ PSD properties for time profiles collected are analyzed and discussed with respect to charge integration time.