Dimple optimization for XPS characterization of TEXTOR tile depositions

The plasma wall-interaction in ITER is facing several challenges including surface erosion, material redeposition and tritium retention. In order to assess some of the possible issues, samples from TEXTOR (Forschungszentrum Jülich Tokamak, Germany) have been studied in this work. A smooth gradient in the form of a dimple should be established to enlarge the view of the depositions in depth before analyzing them with X-ray photoelectron spectroscopy (XPS). The dimple depth was optimized in order to cover the deposition thickness. Profilometer measurements with a confocal microscope were carried out to retrieve information on the profile and to ensure the optimum size/form of the dimples. Scanning electron microscopy measurements were carried out with a JSM 6310 microscope in order to obtain the morphology of the dimple area to verify if the deposition was not put under stress. The chemical composition and distribution of the elements along the dimples and on the surface of the samples was detected with an energy dispersive X-ray spectroscopy (EDS).