Hannover 2020 – scientific programme
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P: Fachverband Plasmaphysik
P 10: Poster Session 2
P 10.24: Poster
Tuesday, March 10, 2020, 16:30–18:30, Empore Lichthof
Influence of oxygen on deuterium retention and release in self-damaged tungsten — •Maximilian Brucker1,2, Kristof Kremer1,3, and Thomas Schwarz-Selinger1 — 1Max Planck Institute for Plasma Physics, Boltzmannstr. 2, D-85748 Garching, Germany — 2Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany — 3Technische Universität München, James-Franck-Straße 1, D-85748, Garching, Germany
Understanding hydrogen isotope (HI) retention in first-wall materials is crucial to predict fuel loss in future fusion devices. The influence of oxygen is discussed controversly in literature. Since in almost all experiments tungsten (W) is exposed to air prior to and/or after loading with deuterium (D), a thin surface oxide layer is naturally present at W surfaces. The effect of such a tungsten oxide layer could play a role on the retention and release of HIs and is examined in ex-situ experiments. As samples, self-damaged W is used. Due to self-damaging of pure tungsten with 20 MeV W ions an about 2 µm thick defect-rich getter layer is created which can trap up to about 2 % HIs. In order to load the damaged tungsten with D, a low-temperature D plasma is used. To examine the effects of outgassing, the samples are first D loaded and then electro-chemically oxidized to oxide layer thicknesses of 25 nm to 100 nm. After oxidation, Rutherford Backscattering Spectroscopy, Nuclear Reaction Analysis and Thermal Desorption Spectroscopy are used to quantify the amount of oxygen, the depth profiles of the retained deuterium and the outgassing behavior. A quantitative discussion of the result will be presented.