Characterisation of a Pixelated Plastic Scintillator for a Coded Aperture Neutron/Gamma Imaging System

This paper experimentally investigates, the suitability of an organic pixelated plastic scintillator for a coded aperture neutron/gamma imaging system. The scintillator used in this study has been designed as a small scaled detector with an individual pixel size of 2.8 mm × 2.8 mm × 15 mm. Individual blocks of the scintillator have been separated from one another with ESR TM reflector foil to provide over 70% of optical isolation between pixels. Individual scintillator cells are arranged into 13×13 array with overall dimension of 39.52 mm × 39.52 mm. In this study the scintillator was attached to a single channel photomultiplier tube to assess its pulse shape discrimination capabilities. Initially the scintillator was irradiated with 137Cs gamma-ray source, and gamma-ray pulses were benchmarked with respect to a mathematical model. The detector was then irradiated with a spontaneous fission source, 252 Cf, and preliminary results suggested good pulse shape discrimination potential of the scintillator. It is believed, that it is the first time a small scale pixelated organic plastic scintillator has been tested in context of PSD capabilities for a coded aperture neutron/gamma imaging system