Accelerator-Based Quantification and Depth Profiling of Hydrogen Isotopes and Impurity Atoms in Wall Materials from Controlled Fusion Devices

The fusion reactor ITER, which is under construction in France, will be a milestone on the way towards fusion energy, generating (as currently planned) for the first time conditions in which 10 times more fusion power output is expected than power input for plasma heating. Currently, the largest device is the Joint European Torus (JET), located in Great Britain. Since August 2011 it has been operated with a full metal first wall with beryllium (Be) limiters in the main chamber and tungsten (W, coatings and bulk metal) in the so-called divertor; JET with the ITER-like wall (JET-ILW). Plasma-material interactions constitute an important part of the research programme. The understanding of fuel retention and material migration belong to the top missions of JET-ILW. This work is focused on the determination of erosion, re-deposition/co-deposition of eroded species with fuel atoms and, on resultant retention of hydrogen isotopes on the JET-ILW wall components. Samples of the components retrieved from the torus after the three consecutive ILW campaigns (ILW-1, ILW-2 and ILW-3) were examined with accelerator-based ion beam analysis (IBA) techniques. This powerful set of methods is one of the crucial tools for surface/sub-surface studies of wall materials from controlled fusion devices.