Modelling and optimisation of neutron detectors based on silicon carbide

Ruggedised high-temperature neutron detectors have been identified as important in many industrial applications, such as the monitoring of nuclear reactors. This study focuses on optimising the thermal neutron detection efficiency of silicon carbide (SiC) neutron detectors. Such detectors employ neutron conversion materials deployed in various geometries either as a planar layer on top of a SiC detector or infilling trenches cut into the detector itself. The converter materials investigated in the present work include boron (10B), boron carbide (B4C), boron nitride (BN), boric acid (H3BO3), and lithium fluoride (6LiF). The option of natural boron-containing or 10B-enriched materials was explored. Simulations using GEANT4 were performed to optimise different configurations to identify the key geometrical features that would maximise detection efficiency. A single-trench detector, filled with 10B, achieved a peak efficiency of 40.9% with an optimal trench depth of 25 μm, while a double trench configuration filled alternately with 10B and 6LiF at the same depth exhibited a lower efficiency of 14.9%. Planar configurations using optimal thickness layers of conversion materials were also explored. Simulation results indicated that single and double-layer planar designs exhibited neutron absorption efficiencies of 5% and 7%, respectively. Comparisons between planar and trench-type designs show a trade-off between efficiency and structural complexity, with trench designs outperforming planar ones in neutron absorption and showing significant improvements in energy deposition. This work provides insights into the optimal design of high-efficiency, rugged SiC-based neutron detectors.