% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Matveev:862841, author = {Matveev, D. and Hansen, P. and Dittmar, T. and Koslowski, H. R. and Linsmeier, Ch.}, title = {{M}odeling of {H}/{D} isotope-exchange in crystalline beryllium}, journal = {Nuclear materials and energy}, volume = {20}, issn = {2352-1791}, address = {Amsterdam [u.a.]}, publisher = {Elsevier}, reportid = {FZJ-2019-03040}, pages = {100682 -}, year = {2019}, abstract = {A reaction-diffusion model with surface occupation dependent desorption [D. Matveev et al., Nucl. Instr. Meth. B 430 (2018) 23–30] has been updated to handle multiple hydrogen species to simulate hydrogen/deuterium isotope-exchange experiments performed on polycrystalline beryllium samples under ultra-high vacuum laboratory conditions. In the experiments subsequent exposures of a sample to hydrogen and deuterium ion beams in direct and reverse implantation order were followed by thermal desorption spectroscopy measurements under a constant heating rate of 0.7 K/s. The recorded signals of masses 2 to 4 (H2, HD and D2) indicate that the second implanted isotope dominates clearly the low temperature release stage ( ≈ 450 K), while both isotopes show a comparable contribution to the high temperature desorption stage ( ≈ 700 K) with only minor effect of the implantation order attributed to a slightly deeper penetration of deuterium compared to hydrogen. Simulations of the implantation and subsequent thermal desorption of hydrogen isotopes are performed to assess the atomic processes behind the isotope-exchange. Simulations were performed under the assumption that the low temperature release stage is attributed to hydrogen/deuterium atoms retained on effective open surfaces (e.g. interconnected porosity) represented in the simulations by a surface with an effective surface area exceeding the nominal exposed surface area by a factor up to 100. Kinetic de-trapping from vacancies with multiple trapping levels and enhanced desorption at surface coverages close to saturation are addressed in the model as possible mechanisms promoting the isotope-exchange. Simulation results suggest the applicability of the model to describe isotope-exchange processes in crystalline beryllium and give a qualitative explanation of the observed experimental facts.}, cin = {IEK-4}, ddc = {624}, cid = {I:(DE-Juel1)IEK-4-20101013}, pnm = {174 - Plasma-Wall-Interaction (POF3-174)}, pid = {G:(DE-HGF)POF3-174}, typ = {PUB:(DE-HGF)16}, UT = {WOS:000500930800016}, doi = {10.1016/j.nme.2019.100682}, url = {https://juser.fz-juelich.de/record/862841}, }