Hydrogen isotope inventories in the ASDEX-Upgrade tungsten coated divertor tiles

摘要

The total hydrogen isotope inventories in the tungsten coated divertor tiles of ASDEX-Upgrade were measured by thermal desorption spectroscopy (TDS) and - in the near surface region - by nuclear reaction analysis (NRA). The highest amounts of deuterium (<= 5 * 10~(22) D/m,~2) are measured in the inner divertor region outside the separatrix due to the formation of a C:H layer on the tungsten by codeposition of deuterium with carbon. The inventories in the outer divertor - where erosion dominates - are generally smaller by an order of magnitude.