Hannover 2016 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 5: Poster Session- Helmholtz Graduate School for Plasma Physics
P 5.7: Poster
Montag, 29. Februar 2016, 16:30–19:00, Empore Lichthof
Deuterium permeation measurements on tungsten using ion-beam-based detection — •Stefan Kapser1,2, Armin Manhard1, and Udo von Toussaint1 — 1Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching, Germany — 2Physik-Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
Tungsten (W) is promising for the inner wall of a future fusion reactor, where it will be exposed to high fluxes of hydrogen (H) isotopes. Knowledge of their diffusion in W is important for safety and economic considerations, particularly concerning tritium. A common method to investigate H diffusion in metals are permeation experiments. Typically, gas loading and mass-spectrometric detection are used. Information about the diffusion can be gained from the temporal evolution of the permeation flux, whose magnitude is determined by the permeability (product of diffusivity and solubility). However, for low-permeability metals, the permeation flux can be unmeasurably small. For W this is the case near room temperature. We present a method that circumvents this problem. It is an improved version of experiments on nickel and stainless steel [1,2]. The W is exposed to deuterium (D) plasma on one side and the permeating D is accumulated in a getter on the other side. A cover prevents D gettering from the gas phase. The amount in the getter is analysed by the nuclear reaction D(3He,p)4He.
[1] W. Möller, B.M.U. Scherzer and R. Behrisch, Nucl. Instrum. Methods, 168 (1980) 289 [2] P. Børgesen, B.M.U. Scherzer and W. Möller, J. Appl. Phys., 57, 2733 (1985)