Pulse shape discrimination performance of a pixelated plastic scintillator (EJ 299 34) for a coded aperture based dual particle imaging system
The pulse shape discrimination performance of a pixelated organic plastic scintillator has been investigated. The scintillator has been built using 169 plastic scintillator blocks (arranged into a 13 x 13 square array) of 2.8 x 2.8 x 15 mm3 each. The scintillator was coupled with a single channel photomultiplier tube. The scintillator was exposed to a mixed field environment provided by 252Cf and its pulse shape discrimination capabilities are presented in this paper. Initial results revealed that a 150 MS/s digitising system was insufficient to separate neutrons from gamma ray photons. Therefore, the experiment was repeated with a 500 MS/s system, which provided improved pulse shape discrimination performance. In order to validate the performance of the pixelated plastic scintillator, it was compared to that of a cylindrical plastic sample. Tests were also carried out in moderated neutron and gamma ray fields of 252Cf. The results indicate that acceptable levels of pulse shape discrimination are obtained for the case of a pixelated scintillator, when the higher sampling rate digitiser was used.
Journal of Instrumentation