Ion Microanalysis and Implantation Applied to Fusion Surface Research

Ion microanalysis and implantation have been used to investigate and analyze plasma-surface interactions relevant to fusion plasma materials. Previous results for pure metals are reviewed and new results are presented for TiB2 coatings for Tokamak surfaces. Enhanced trapping of implanted, low-energy hydrogen has been shown to occur at room temperature in W, Au, Pd, Mo, Nb, and TiB2 for He or other ion predamage. Hydrogen depth profiles obtained using 1H(19F,¿¿)16O resonant nuclear reaction show that the H decorates the He damage profiles at traps whose concentration is proportional to the He-induced damage. For room temperature implantation in TiB2, H is trapped at the end of range, and isochronal annealing indicates that the H is lost by release from traps followed by rapid diffusion. For He predamaged samples, annealing at 400°C causes the H to be retrapped in the region of the He-induced damage at traps whose cross section is ¿ 1.8 × 10-18cm2/trap.