The atomistic understanding of retention and release processes of deuterium in beryllium is reached by comparing well-defined experiments on Be(0001) and [11][12][13][14][15][16][17][18][19][20] single crystals, as well as polycrystalline Be to simulations. The experimental desorption spectra are modelled as a coupled reaction diffusion system (CRDS). The single atomistic steps are described by a set of rate equations. Activation energies for the single processes are calculated from density functional theory. (0001) is attributed to anisotropic self-interstitial diffusion influencing the availability of monovacancy traps during implantation. Additionally, desorption spectra with various temperature ramps recorded on polycrystalline Be were successfully reproduced with the CRDS code. D 2 release from polycrystalline Be occurs at lower temperatures than from the single crystals. This is attributed to fast D diffusion along grain boundaries.

No abstract