Neutronic Design on a Small Accelerator-Based 7Li (p, n) Neutron Source for Neutron Scattering Experiments

As 7Li (p, n) reaction near the threshold energy yields lower energy neutrons than other reactions, including (γ, n) reactions, it will enable us to develop a compact neutron source. We performed neutronic optimization studies on a cold neutron source based on the 7Li (p, n) reaction, and further compared its neutronic efficiency with that of other sources based on different reactions. It turned out that the cold neutron source using the 7Li (p, n) reaction with 2.0 MeV protons showed about 1.5 times higher efficiency for cold neutron production per produced neutron in a target in comparison with other reactions. Simulation calculation results taking into account the shield materials for neutrons and γ-rays have indicated that a very compact system can be realized.