Moderation device design for detecting hidden highly enriched uranium based on D-T neutron generator

Abstract

Preventing the proliferation of highly enriched uranium (HEU) is an important issue all over the world. A neutron moderation device for detecting hidden HEU is designed based on a portable D-T neutron generator. The materials of each part of the moderation device are selected and the parameters are optimized to improve the moderating efficiency by Monte Carlo method. Compared with no moderation measures, the proportion of thermal neutron flux with moderation increased from 0.93% to 47.8%, and the proportion of epithermal neutron flux increased from 2.62% to 11.5%. The detection of HEU hidden in common cargo by using this device was then simulated, and the existence of HEU is determined by recording the difference of the neutron flux. In the simulation detection, a BC-501a liquid scintillation detector is used as neutron detector. The results show that the device with an optimized moderation system can detect the hidden HEU effectively.