New temperature-programmed desorption measurements from implanted single and polycrystalline beryllium were presented, as well as new computational results on the diffusion of interstitials through an undisturbed beryllium lattice. The threshold fluence for the appearance of a low-temperature desorption region around 460K after implantation of 1keV D ions into polycrystalline beryllium was determined to be 1.2 x 1021/m2. In the high-temperature release region, an implantation energy-dependent shift in desorption temperatures was observed after implantation to very low fluences. It was explained by the variation of the mean distance from the surface for atoms implanted at different energies rather than by changes in the activation energy for de-trapping. Morphological investigations of the surface of polycrystalline beryllium after several implantation and annealing cycles show a strong dependence of the damage on the surface orientation of grains. This dependence correlates with the preferred diffusion of interstitials parallel to basal planes of the beryllium lattice as calculated within the formalism of density functional theory.

Towards a Detailed Understanding of the Mechanisms of Hydrogen Retention in Beryllium. M.Oberkofler, M.Reinelt, A.Allouche, S.Lindig, C.Linsmeier: Physica Scripta, 2009, T138, 014036