Deuterium retention in tungsten at Fuego Nuevo II

Tungsten and tungsten-based materials are one of the main candidates for plasma-facing components in a future fusion power plant. Many of the retention and radiation damage studies are performed using ion beams rather than plasmas. We are exploring the possibility of using small plasma devices of the type of plasma-guns to perform plasma-wall-interaction studies on fusion relevant materials. We exposed tungsten polycrystalline samples at room temperature to deuterium plasmas in the facility Fuego Nuevo II at UNAM. The samples were analyzed using electron microscopy for surface topology and cross-section for in-depth modifications and Ion Beam Techniques. The SEM studies show erosion of the surface and an affected layer of typically ~220 nm. The ion beam analysis using 700 keV ³He ions shows a deuterium retention ratio D/W of~0.2 up to a depth of 250 nm.