Studying processes of hydrogen interaction with metallic surfaces in situ and in real-time by ERDA

A special cell was constructed for studying the interaction of hydrogen with materials. It enabled exposure of samples to a neutral hydrogen atmosphere and simultaneous concentration depth profiling of H and D. The concentration of individual hydrogen isotopes was measured by elastic recoil detection analysis (ERDA) using a 4.2 MeV 7Li2+ probe beam. The measurements reported here were performed on Ti and W. The time evolution of processes occurring on the surface and in the bulk was studied by successive recording of ERDA spectra. For specific conditions in the cell a model describing adsorption and desorption of deuterium molecules on a W surface was proposed. Sticking and recombination coefficients were obtained by fitting the time evolution of deuterium concentration.