Impurity Deposition and Surface Erosion on Probes in the Bundle Divertor of DITEa

Abstract

Amorphous carbon and single crystal silicon collector probes were inserted into the bundle divertor of DITE on the electron drift side. Onto the carbon, 2.7×1016 atoms/cm2 antimony was evaporated and for silicon 5×1015 atoms/cm2, Sb+ implantation was carried out prior to the exposure to plasma. Thus these probes not only collected impurities but were able to provide information on the material loss as well. Using RBS analysis it turned out that the predominant species detected were carbon, oxygen and stainless steel components. Other impurities such as Ti, S, Cl, Mo, Cu and Pb were also found. Their radial distribution is reported. On evaporated probes an Sb loss with typical value of 3 to 5×1015 atoms/cm2 discharge was observed.