Neutron-Gamma Pulse Shape Discrimination using 3D-Printed Plastic Scintillator with High-Concentration PPO

Abstract

Neutron measurement technologies are being studied due to the demand in Nuclear Fusion, Accelerator facilities, Nuclear Non-Proliferation Treaty (NPT), etc. Since neutron fields are typically present with gamma-ray, the separation technique is necessary such as pulse-shape discrimination (PSD) for neutron detection. Decay-time constants of plastic scintillators depend on the type of particle. Thus, plastic scintillators are capable of PSD measurement. Plastic scintillators can be manufactured by 3D-printing technique based on digital lighting processing (DLP). The advantages of the technology are simple way, fast production, low cost and customizing easily. In this study, the neutron-gamma (n-γ) separation was attempted using 3D-printed plastic scintillators with the 2,5-diphenyloxazole (PPO). The n-γ separation performance of plastic scintillators composed of polymer, which is doped with the PPO, is affected by concentration of PPO. Therefore, this research was conducted to dissolve various concentrations of PPO and made each sample with different proportions. The samples were evaluated by Figure of Merit (FOM) for the capability of n- γ discrimination. The sample of 30wt% PPO has 1.73 ± 0.02 of FOM from 300 keVee to 1,000 keVee. It is expected that continuous research will make it possible to produce commercial-level neutron detectable scintillators by 3D-priniting technique.