Plasma-Wall Interaction on Boronized Tiles Studied via X-ray Photoemission Spectroscopy Analysis

Tiles coming from different positions of the first wall of RFX have been analyzed via Xray Photoemission Spectroscopy (XPS) at Istituto di Fisica del Plasma. The objectives are to study the erosion and deposition effects during the discharge and to look at the quality of the boron deposition. There is a good agreement between Rutherford Backscattering and XPS on identifying the metals of the first chamber deposited, as oxides, on the surface of the tiles. The different erosion rates, during the plasma discharges, and the differential sputtering rates during XPS profiling, modified their original concentrations. The high concentration of oxygen pointed out a boronization driven in presence of oxygen gas.