Dynamics of hydrogenic retention in molybdenum: First results from DIONISOS

The DIONISOS (Dynamics of ION Implantation and Sputtering of Surfaces) experiment is described. DIONISOS features steady-state plasma exposure of material surfaces, with simultaneous, in situ, non-destructive depth profiling on the same surfaces with ion beam analysis (IBA). A steady-state RF helicon plasma source produces a fusion ‘edge-like’ low temperature (T ∼ 1–10 eV), high-density (⩽1017–18 m−3), steady-state, cylindrical, plasma (ϕ ∼ 50 mm). The exposure stage allows for the control of sample surface temperature (300–800 K), incident ion energy (10–500 eV), and ion beam and magnetic field incident angle (360° rotation), during bombardment with high plasma flux (∼1020–1022 s−1 m−2). First results from DIONISOS show a large and evolving concentration of deuterium (∼1000 appm) trapped deep (∼5 μm) in molybdenum. IBA during plasma exposures shows the surface dynamic deuterium inventory increased by a factor of 2 over the ‘long-term’ trapped inventory at an incident ion flux density of ∼1.5 × 1021 D/m2 s.