Radiation effects on the deuterium diffusion in SiO2

Different oxides, mainly fused silica and aluminium oxide, are candidate materials to be used in different systems of ITER. Some applications require their use as confinement barriers for tritium and other radioactive products. The effect of radiation on diffusion mechanisms of fused silica is studied. To help clarify this phenomenon in a qualitative way, radiation effects on the behaviour of the implantation profile of deuterium are measured for fused silica. Deuterium has been introduced into the samples by 50 keV ion implantation and later on irradiated at different temperatures to induce diffusion. The modification of the implantation profile has been determined by Elastic Recoil Detection Analysis (ERDA) using Si ions. It is observed that high dose rate ionizing irradiation (over 100 Gy/s) induces changes in the D profile even at room temperature. No significant effects are observed for lower dose rate ionizing radiation effects or displacement radiation effects from 1.2 MeV Si ion irradiation.