A high-efficiency, low-Cerenkov Micro-Layered Fast-Neutron Detector for the TREAT hodoscope

作者：Ghosh Priyarshini^*; Fu Wenkai; Harrison Mark J; Doyle Patrick K; Edwards Nathaniel S; Roberts Jeremy A; McGregor Douglas S

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2018, 904: 100-106.

DOI：10.1016/j.nima.2018.07.035

This paper presents an enabling technology for high-efficiency fast-neutron detection for the Transient Reactor Test (TREAT) Facility hodoscope. The hodoscope is currently outfitted with 25.4-mm long Homyak buttons for fast-neutron detection. However, they require improvements, as they suffer from low detection efficiency, Cerenkov radiation contaminating the signal, and non-linearity of detector response at large transients. To address these issues, a layered ZnS:Ag device has been constructed. The layered design provides various advantages: it incorporates greater scintillation volume, Cerenkov background is significantly reduced by eliminating the need for additional light guides, and the detection process is simplified by achieving gamma-ray rejection using only pulse-height discrimination. The result is a greater number of fast neutron counts with reduced background noise contaminating the signal. On being irradiated with a Cf-252 source (whose neutron energy spectrum closely mimics a reactor fission spectrum), a 25.4-mm long layered device was found to exhibit an intrinsic fast-neutron detection efficiency of 8.1% for neutrons with an average energy of 2 MeV, while a 43-mm long device allows for a greater number of fast neutron to be detected, increasing the efficiency to 9.1%. Further lengthening of the device up to 20 cm has been numerically predicted to exhibit even higher efficiencies. The detectors can be mass-produced easily and inexpensively.

• 出版日期2018-10-1