Characterization of a 4H–SiC neutron detector in the neutron field of an accelerator-based BNCT facility

4H–SiC features excellent properties such as wide bandgap and fast carrier drift velocity, making it a good semiconductor candidate for developing neutron detectors with hard resistance, fast response, high charge collection efficiency and excellent thermal stability. However, to date there remains a scarcity of comprehensive studies on the performance of 4H–SiC based neutron detectors working in the neutron field of an accelerator-based Boron Neutron Capture Therapy (AB-BNCT) facility. In our work, a 6LiF thermal neutron convertor was coated with the 4H–SiC detector to enhance the sensitivity to thermal neutrons by employing the 6Li (n, α) T nuclear reaction. The 4H–SiC detector yields a pulse height spectrum which has a clear Triton peak isolated from other structures, demonstrating its good background rejection ability. Good performance is also revealed by the excellent linear relationship between count rates of the detector and beam intensities of the AB-BNCT accelerator, consistency between the detector and a standard neutron yield monitor of the AB-BNCT in their time-dependent count rates, and long-time stability in both the count rate and the pulse height spectrum shape. Based on the TCAD simulations, the 4H–SiC detectors were found to have high resistance to neutron radiation in BNCT, with charge collection efficiencies exceeding 95 % even at neutron fluences up to 1016 cm−2. Due to the compact volume, the 4H–SiC detectors have the potential to develop high-performance neutron fluence and spectrum monitoring instruments for AB-BNCT facilities.