Simulated Bombardment of Diamond With Hydrogen Isotopes

Diamond is a material of interest for windows, sensors, and even plasma facing materials (PFMs) within the first wall of fusion reactors. As with any material within the first wall, both fuel retention and hydrogen etching must be considered. In order to develop understanding of diamond’s interaction with hydrogen in fusion relevant conditions, a series of repeated single bombardment molecular dynamics simulations have been performed. The impact of incident hydrogen mass, energy, and incident angle, as well as the diamond temperature and orientation were all explored. It was found that vacancy formation was restricted to the top unit cell (UC), (110) and (111) surfaces exhibited a notable decrease in vacancies compared with (100), and reflection of incident atoms was largely dictated by the atom’s vertical momentum. In general, in the case of pristine diamond, changes in surface orientation and temperature appear to have minimal impact on retention. However, both these variables did affect vacancy formation, suggesting they could become significant as the surface becomes damaged.