Neutronics analysis of the target-moderator–reflector (TMR) configuration for compact long pulsed neutron sources

The compact pulsed neutron source can play an important role in the research, education, user training, and development of the advanced neutron scattering instruments. The materials for the target, moderator, reflector (TMR) and their configurations must be optimized to get the optimal yield of neutrons with energy in the range of 0.001–0.1 eV order. Several kinds of materials of the TMR, their configurations, and their dimensions are investigated by the Monte Carlo simulation and optimized for developing the compact pulsed neutron source. The results would contribute to the construction of the Compact Pulsed Hadron Source (CPHS) at Tsinghua University, China.

► Be, CH4 and H2O are used as target, moderator and reflector (TMR) of a neutron source.
► Dimensions and relative positions of TMR are optimized for cold-neutron production.
► Slab moderator produces highest fast and cold neutrons in forward extraction.
► Backward extraction yields least fast neutrons but also reduces cold-neutron flux.
► 90̊-extraction yields fast vs. cold neutrons intermediate of forward and backward cases.