Comparison between Silicon-arbide and Diamond for Thermal neutron detection at Room Temperature

Abstract

Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron yield and reactor environment. Such detector must be able to operate at high neutron flux levels (>109 n/(cm2s)) and discriminate the neutron and gammaresponses in the nuclear reactor’s mixed neutron-gamma environment. Moreover such a detector must have fast and stable response over considerable long period of use. Silicon Carbide and Diamond are the most attractive semiconductor materials for neutron detection in severe media (high temperature, high gamma dose rate and high neutron fluxes). Thanks to their outstanding properties, such as high displacement threshold energy and wide band gap energy, SiC and Diamond can operate in harsh environment (high temperature and high radiation level). The aim of this work is to compare the ability to detect thermal neutrons of these two semi-conductors at the same irradiation conditions. For this purpose, the neutron irradiation tests of detectors were implemented at MINERVE research reactor at CEA Cadarache. Both kinds of detectors show the linear evaluation of the count rate in the thermal neutroninduced peak with the reactor power. Our results reveal that the 4H-SiC-based neutron detector shows worse neutron to gamma discrimination in comparison to the sCVD diamond-based detector when the reverse bias voltage is applied to the 4H-SiC diode. The best neutron to gamma discrimination, though, is obtained with the 4H-SiC-based detector at 0V.