Carbon impurity behavior on plasma facing surface of tungsten

Abstract In order to study the behavior of carbon ions implanted together with hydrogen ions into tungsten, 1 keV H 3 + (main component) with 0.1–0.8% of carbon ions were irradiated to pure sintered tungsten and depth profiles of carbon at the tungsten surface were measured. Carbon depth distributions at less than about 1000 K were much broader than the carbon ion range distributions, which could be attributed mainly to recoil implantation. Most of injected carbon atoms formed WC (not W 2 C) for both C ∼0.1% and ∼0.8% cases, which is different from the chemical states of carbon atoms thermally diffused into the bulk tungsten (W 2 C). Enhanced sputtering of carbon atoms at the tungsten surface was observed at 913 K, which might be owing to a low chemical sputtering yield for carbon.