Fabrication and performance evaluation of GaN thermal neutron detectors with 6LiF conversion layer**Project supported by the National Natural Science Foundation of China (Grant Nos. 61964001 and 61961001), the State Key Laboratory of Particle Detection and Electronics (Grant No. SKLPDE-KF-2019), the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 20192BAB207033 and 20181BAB202026), the Foundation of State Key Laboratory Breeding Base

Abstract

A GaN-based pin neutron detector with a 6LiF conversion layer was fabricated, and can be used to detect thermal neutrons. Measurement of the electrical characteristic of the GaN-based pin neutron detector showed that the reverse leakage current of the neutron detector was reduced significantly after deposition of a 6LiF conversion layer on the detector surface. The thermal neutrons used in this experiment were obtained from an 241Am–Be fast neutron source after being moderated by 100-mm-thick high-density polyethylene. The experimental results show that the detector with 16.9-μm thick 6LiF achieved a maximum neutron detection efficiency of 1.9% at a reverse bias of 0 V, which is less than the theoretical detection efficiency of 4.1% calculated for our GaN neutron detectors.