title: Strongly reduced penetration of atomic deuterium in radiation-damaged tungsten.
abstract: Radiation-damaged tungsten is exposed to high-flux, low-energy deuterium plasmas at self-bias conditions. We observe that the fraction of deuterium that penetrates is only 10(-5)-10(-7) of the plasma flux and strongly dependent on the local surface temperature. We propose that deuterium does not directly penetrate bulk tungsten but that it thermalizes at the surface, where it forms a protective chemisorbed layer. We find an energy barrier of 1-2 eV between the surface and bulk, causing the influx of deuterium to be low as compared to the number of defects and leading to slow filling of the damaged layer.
authors: FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, NL-3439 MN Nieuwegein, Netherlands.
authors: M H J
authors: MH
authors: 't Hoen
authors: Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching, Germany.
authors: M
authors: M
authors: Mayer
authors: FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, NL-3439 MN Nieuwegein, Netherlands and Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam, Netherlands.
authors: A W
authors: AW
authors: Kleyn
authors: FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, NL-3439 MN Nieuwegein, Netherlands.
authors: P A
authors: PA
authors: Zeijlmans van Emmichoven