Neutron-gamma separation study for ZnS(Ag)/6LiF scintillator and silicon photomultipliers

Abstract

Registration of thermal neutrons while simultaneously suppressing or rejecting accompanying gamma-ray background is an important task for many fields. We report on two different experimental neutron-gamma separation studies, utilizing a ZnS(Ag)/6LiF scintillator and pulse height discrimination technique: one is a comparison of the responses of a ZnS(Ag)/6LiF scintillator and a ‘reference’ GAGG(Ce) scintillator when irradiated by gamma sources 137Cs and 241Am; and the second is testing a dual readout, where a photosensor coupled to the ZnS(Ag)/6LiF scintillator screen on each side was irradiated by neutrons (252Cf neutron source). For all measurements the silicon photomultipliers (SiPMs) PM3315-WB-A0 (3x3 mm2 sensitive area, 15 μm cell pitch) manufactured by KETEK were used as a photosensor. High-speed digital oscilloscope LeCroyWR 620zi with a sample rate of 10 GS/s was used as a data acquisition system.