Fast neutron detection with silicon carbide semiconductor radiation detectors

Silicon carbide (SiC) radiation detectors are being developed for high-temperature applications in harsh radiation environments. Among these applications are characterization of nuclear reactor fuel and detection of concealed fissionable materials, which both require the optimization of SiC fast neutron detectors for detection and quantification of fission neutrons. In order to enhance fast-neutron sensitivity, proton recoil techniques are being used. Fission neutrons were simulated by using a 2.5-MeV deuterium-deuterium (D-D) neutron generator. In order to optimize the neutron detection sensitivity, 2.5-MeV neutron proton-recoil response measurements were made as a function of polyethylene converter layer thickness. Measurements were also made of the sensitivity of the SiC proton recoil detector as a function of angle of incidence of the neutrons. As expected from the angular sensitivity of the detector response, detection of neutrons normally incident to the detector face is favored allowing discrimination of background neutrons and possibly supplying information on the fissionable material location or configuration.