Performances of 4H-SiC Schottky diodes as neutron detectors

Large area 4H-SiC Schottky diodes equipped with a 6LiF converter were tested as neutron detectors in the epithermal column realized for Boron Neutron Capture Therapy (BNCT) applications at the fast reactor TAPIRO (ENEA Casaccia Roma). The neutron spectra were assessed using the Monte Carlo code MCNP-4C. The performances of SiC detectors were evaluated with neutron fluences in the range of 10^9–10^13 cm2 which is typical for BNCT. Spectra of alpha and tritium particles generated by 6Li(n,a)3H reaction were collected at various neutron fluences and spectra obtained by interposing polyethylene moderators of different thickness. Only weak damaging effects primarily due to the alpha particles were observed; at neutron fluence of 10^13 cm2 the count rate decreased by <0.3%. The experimental results were compared with the theoretical ones calculated using MCNP-4C and SRIM codes.