DUAL PARTICLE IMAGING WITH IRIDIUM-BISMUTH AND FAST-CURING PLASTIC SCINTILLATORS

Recent material advancements in plastic scintillators enable marked increases in material light yield, detection efficiency, pulse-shape discrimination, and array production rates. These advances may resolve significant capability gaps for low-cost, portable, and durable dual-particle imaging (DPI) systems for nuclear safety, security and safeguard purposes. Two such materials, both 21% bismuth-loaded plastics utilizing iridium complex fluorophores (Ir-Bi-Plastic) were experimentally evaluated for DPI purposes as a small, pixelated radiographic array and compared to similar arrays made from EJ-200 and EJ-256 (5 wt% Pb). Experimentation involved separate exposures to 370 kVp x-rays and 14.1 MeV neutrons when paired with a digital radiographic panel, and array performance was evaluated using ASTM methods for dSNRn determination. Additionally, the development of fast-curing plastic scintillator (FCPS) formulations is highly attractive because it facilitates the 3D-printing of complete pixelated plastic scintillator arrays for radiation detection and localization. Future advancements in this area will significantly reduce the time and costs associated with current array manufacturing techniques. Some early investigations of FCPS samples sensitized with 5 wt% Bi is discussed herein, with their gamma detection efficiencies and associated light yields compared to an equivalent sample of EJ-256. These early unoptimized samples provided similar but not superior performance to EJ-256, and this is an ongoing area of research at the Air Force Institute of Technology.