High speed detection of thermonuclear neutrons with solid state detectors

Inertial-confinement fusion experiments generate thermonuclear neutrons on subnanosecond time scales. To understand the burning of DT fuel a 14-MeV neutron detector with subnanosecond time response has been developed. The detectors are made of neutron-damaged, bulk GaAs with electron-hole recombination times of 60 ps. The conductivity of the detector is modulated by the energy deposited by the neutrons interacting in the detector to free carriers. The fast recombination time of this material quickly removes these radiation-generated carriers from the conduction process, resulting in extremely fast response times. The measurements and calculations of the sensitivity of the detectors are in good agreement.<>