Performance Assessment of a Compact Neutron Detector Module Based on Scintillating Composites

A composite fast neutron detector module based on the ⁶Li(n,α)³H reaction in ⁶Li-enriched GS20^® scintillating glass has been engineered to be compact, robust, and tunable. The solid scintillating composite consists of only three components, all commercially sourced, and can be optically coupled to silicon photomultipliers (SiPMs) to create a highly capable and portable neutron detector module. The composite provides moderation of incident fast neutrons through an optically transparent organic matrix and achieves high gamma rejection by the use of small scintillating particles. The performance of the module was assessed by measurements of the die-away time and the sensitivity to both gammas and neutrons. Controlled scintillation light losses enable determination of the neutron capture location along the length of the cylindrical composite. Optical raytracing was used to predict the light-transport efficiencies and the longitudinal position dependency of scintillation events within the module. These assessments indicate that this module can be effective in the detection of nuclear material for nonproliferation, safeguards and security applications, and in fundamental and applied science.