Study of n-γ discrimination by zero-crossing method with SiPM based scintillation detectors

The paper presents a study of n∕γ discrimination with 4x4 ch and 8x8 ch Multi Pixel Photon Counter (MPPC) arrays in neutron detectors based on Stilbene and EJ299-33 plastic scintillators. The n∕γ discrimination showed an excellent capability of the MPPC arrays, comparable to that observed earlier with the classical PMTs. Particularly, an application of a zero-crossing method of n−γ discrimination prevented deterioration of the discrimination by the slow response of the Silicon Photomultiplier (SiPM, or MPPC interchangeably) array related to its large capacitance. It was confirmed by a good agreement of the Figure of Merit normalized to the number of photoelectrons determined for the MPPC arrays and XP5500 PMT.