Radioluminescence characterization of SiC and SiC/SiC for 1.8Â MeV electron irradiation

As a first step to permit in situ monitoring of radiation induced degradation in SiC materials, characterization by means of 1.8 MeV electron induced radioluminescence (RL) was performed. RL has been measured at 75 Gy/s and 5.4 kGy/s and temperatures from 15 to 450 °C (288-723 K), to total doses ⩽200 MGy for hot pressed, reaction bonded, cubic CVD, and PVT (nitrogen doped, semiconductor grade wafer) SiC to identify common emissions, and study dose rate, temperature, and dose behaviour. 2D and 3D SiC/SiC have also been irradiated to detect if possible separate RL emissions from the matrix and fibre constituent materials. All four SiC materials exhibit RL in the 1.5-3.5 eV range, with a main band near to 2.1 eV. Increasing irradiation temperature decreases the emission intensities, but they recover on decreasing the temperature with an indication of both quenching and defect annealing. With dose all the emission intensities decrease. For the CVD and the PVT SiC the main emission band is structured with different components clearly visible. In the PVT SiC, one of these components not only decreases with dose, but changes energy, consistent with structural modification. In contrast no emission has been observed for the 2 and 3D SiC/SiC materials.