Radiation detector based on 4H-SiC used for thermal neutron detection

In this work we have focused on detection of thermal neutrons generated by Pu-239-Be isotopic neutron source. A high quality liquid phase epitaxial layer of 4H-SiC was used as a detection region. The thickness of the layer was 70 mu m and the diameter of circular Au/Ni Schottky contact was 4.5 mm. Around the Schottky contact two guard rings were created. The detector structure was first examined as a detector of protons and alpha particles for energy calibration. Monoenergetic protons of energies from 300 keV up to 1.9 MeV were used for detector energy calibration and a good linearity was observed. The energy resolution of 35 keV was obtained for 1.9 MeV protons. The (LiF)-Li-6 conversion layer was applied on the detector Schottky contact. In the experiment we used different thicknesses of conversion layers from 5 mu m up to 35 mu m. Measured detected spectra show two parts corresponding to alpha particles detection in lower energy channels and H-3 in higher energy channels. We have also performed simulations of thermal neutron detection using MCNPX ( Monte Carlo N-particle eXtended) code. The detection efficiency and the detector response to thermal neutrons was calculated with respect to the (LiF)-Li-6 layer thickness. The detection efficiency calculation is found to be in good agreement with the experiment.