Design of a novel neutron spectrometer for DT fusion diagnosis

Design of a novel spectrometer for measurements of neutrons in the energy range 9 - 17 MeV has been proposed. Based on proton recoil method and magnetic analyzing technique, the spectrometer can be used to determine DT fuel areal density (<ρR>) and ion temperature under steady state and pulsed radiation field. The detection efficiency is about 10-8 for measuring 14 MeV neutrons with an energy resolution of about 4%. A neodymium-iron-boron permanent dipole was used for the magnetic analyzing system and CR-39 track detectors were used in the focal plane. The system has been tested with 239Pu α source and a corresponding particle transport simulation program has been worked out. Performance of the spectrometer was investigated with Monte Carlo simulation, experiment data and the transport simulation. Due to its good performance, compact structure, and availability for both steady state and pulsed radiation field, the spectrometer can be effectively used for fusion research in the future. (authors)