A SiPM-based ZnS:6LiF scintillation neutron detector

Abstract

In the work presented here we built and evaluated a single-channel neutron detection unit consisting of a ZnS:6LiF scintillator with embedded WLS fibers readout by a SiPM. The unit has a sensitive volume of 2.4×2.8×50mm3; 12 WLS fibers of diameter 0.25mm are uniformly distributed over this volume and are coupled to a 1×1mm2 active area SiPM. We report the following performance parameters: neutron detection efficiency ~65% at 1.2Å, background count rate <10−3Hz, gamma-sensitivity with 60Co source <10−6, dead time ~20μs, multi-count ratio <1%. All these parameters were achieved up to the SiPM dark count rate of ~2MHz.We consider such detection unit as an elementary building block for realization of one-dimensional multichannel detectors for applications in the neutron scattering experimental technique. The dimensions of the unit and the number of embedded fibers can be varied to meet the specific application requirements. The upper limit of ~2MHz on the SiPM dark count rate allows to use SiPMs with larger active areas if required.