Deuterium trapping and release in Be(0001), Be(11-20) and polycrystalline beryllium

The atomistic understanding of retention and release processes of deuterium in beryllium is reached by comparing well-defined experiments on Be(0 0 0 1) and Be(11–20) single crystals, as well as polycrystalline Be to simulations. Temperature programmed desorption spectra are recorded after implantation of D fluences of ∼3 × 10 19 m −2 . The experimental 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. The changes in retained amounts and desorption temperatures for different crystal orientations, implantation depths and temperature ramps were successfully reproduced with the CRDS code. Anisotropic self-interstitial diffusion and fast diffusion along grain boundaries are among the important mechanisms that have to be taken into account in the simulations.