High-pressure Helium-3 Scintillation Position-sensitive Detector of Thermal Neutrons

The objective of this study is to demonstrate the feasibility of constructing a compact neutron detector that is sensitive to thermal and epithermal neutrons and has high rejection efficiency relative to gamma-ray background. A two-channel high-pressure He scintillation detector is considered for the detection of neutrons in coincidence mode. The detector consists of two large avalanche photodiodes viewing a gas volume filled with pressurized He. Experiments with the detector demonstrate high efficiency to neutrons and high rejection ability to gamma rays. Position sensitivity of the detector to thermal neutrons is demonstrated and confirmed with computer simulations.