Abstract: Neutron energy spectrum is one of the most important characteristic parameters in the diagnosis of nuclear reaction process. Multi-directional weighting method was established for D-T fusion neutron spectrum measurement. The detectors were arranged at several different angles of the recoil proton outgoing direction. The final neutron spectrum was determined by the recoil proton spectrum and its corresponding weight values. The Geant4 simulation results showed that, compared with single direction detection, the multi-directional weighting method could improve the detection efficiency and the solution accuracy. The simulation data of multi-directional weighting method were compared with the neutron source and actual D-T fusion energy spectrum, and the practicability and validity of the method were verified.

Key words: neutron energy spectrum, D-T fusion, multi-directional weighting method, Geant4