Influence of thin surface oxide films on hydrogen isotope uptake and retention in tungsten

Deuterium (D) uptake through thin (30-50 nm) surface oxide films into metallic tungsten (W) was studied by using self-damaged W as a getter layer. Depth-resolved concentration profiles of D and oxygen were obtained after D plasma exposure by nuclear reaction analysis and Rutherford backscattering spectrometry. It was found that the oxide film effectively blocks D permeation into the metallic W. Additionally oxygen is slowly removed from the surface-near region of the oxide film during plasma exposure.