Ion implanted deuterium retention and release from clean and oxidized beryllium

The deuterium retention and thermal recycling behavior of clean and oxide-covered beryllium is investigated by a combination of temperature programmed desorption, X-ray photoelectron spectroscopy and other methods. From the experimental results, the retention mechanisms are deduced and activation energies for the release processes are obtained from modeling. Implanted deuterium at 1 keV kinetic energy is trapped locally in ion-induced defects with a release temperature above 700 K. At a local deuterium concentration greater than 0.35 D/Be, the beryllium bulk is supersaturated. This leads to the formation of additional binding states with a release temperature of 450 K and formation of BeD2, which decomposes at 570 K. The amount of deuteride formed is influenced by the target temperature during implantation. The Be surface and BeO surface layers have no rate-limiting influence on the thermal release process.