Physical design of high pressure ⁴He gas scintillation neutron detector

High pressure ⁴He gas scintillation neutron detector is a new kind of fast neutron detector with advantages of fast response, good n-γ discrimination and high detection efficiency. In this work,we report the influences of geometrical dimension and pressure on the performance of high pressure ⁴He gas scintillation neutron detector by Monte Carlo method. The design of ⁴He detector is optimized. The neutron detection efficiency increases linearly with the increase of pressure. The detection efficiency of neutron decreases when the length of detector increases. The detection efficiency of neutron increases with the diameter of detector increasing. The detector having pressure at 120 atm, length with 200 mm and diameter with 44 mm can achieve 4.28% intrinsic efficiency for approximate fission spectrum neutron (average energy 1.05 MeV). This provides theoretical instructions for subsequent fabrication of the detector. (authors)