Magnetic proton recoil spectrometer for neutron spectrum measurements

According to the requirement of implosions at the Shengguang-Ⅲ facility and its prototype, the design of a magnetic proton recoil spectrometer was illuminated, and it was simulated by the Monte-Carlo code Geant4. Neutron spectra in the range of 6~30 MeV can be measured by the spectrometer, and it is sensitive when neutron yield is larger than 1012. The whole neutron spectrum produced in implosions can be measured with the spectrometer. Simulation results show that the detection efficiency of the spectrometer is bigger than 10-11 in measuring 14 MeV neutrons with an energy resolution of about 1%, and the signal-to-background ratio of the spectrometer is larger than 10. The spectrometer can be used to diagnose ion temperature of DT fuel at the Shengguang-Ⅲ facility prototype.