Influence of tungsten microstructure and ion flux on deuterium plasma-induced surface modifications and deuterium retention

Abstract

The influence of surface temperature, particle flux density and material microstructure on the surface morphology and deuterium retention was studied by exposing tungsten targets (20μm and 40μm grain size) to deuterium plasma at the same particle fluence (1026m−2) and incident ion energy (40eV) to two different ion fluxes (low flux: 1022m−2s−1, high flux: 1024m−2s−1). The maximum of deuterium retention was observed at ∼630K for low flux density and at ∼870K for high flux density, as indicated from the thermal desorption spectroscopy data (TDS). Scanning electron microscopy observations revealed the presence of blisters with a diameter of up to 1μm which were formed at high flux density and high temperature (1170K) contrasting with previously reported surface modification results at such exposure conditions.