Design and simulated performance of a high-resolution magnetic proton recoil spectrometer for deuterium–tritium neutrons

Abstract

Neutron emission energy and time spectra of deuterium–tritium plasma contain abundant information about the fusion yield, ion temperature, and nuclear burn history. Magnetic recoil spectrometers have been employed in measuring time-integrated energy spectra in inertial confinement fusion (ICF) experiments. As the fusion yield increases, time-resolved neutron diagnostics is urgently desired for understanding complex fusion physics. Herein, we design a compact magnetic proton recoil (MPR) spectrometer based on a 90 degree permanent magnet. The entrance and exit of the magnet are second-order shapes to eliminate two major second-order aberrations. The energy resolution and time resolution for 14MeV neutrons achieve 97keV and 1.6ns, respectively, under the detection efficiency of 7.4×10−8cm2. A quadratic relation is found between detection efficiency and energy resolution when configurations are optimal. Monte Carlo simulations are accomplished to study the performance in measuring time-integrated energy spectra, emission time spectra, and time-resolved energy spectra, demonstrating the potential of high-resolution MPR spectrometers in future high-yield ICF experiments.