SPUTTERING BY HYDROGEN-ION BOMBARDMENT AND SUBLIMATION OF BORON-DOPED AND VANADIUM-DOPED GRAPHITE

For boron- and vanadium-doped graphites, the yields of radiation - enhanced sublimation (RES) and chemical sputtering by hydrogen ion bombardment were measured by means of a weight loss method, by using an electron cyclotron resonance (ECR) hydrogen ion irradiation apparatus. In addition, the thermal sublimation rates of these materials were measured by using the same apparatus. The reduction of the RES yield due to the doping of boron or vanadium was not clearly observed. The chemical sputtering yields for boron- and vanadium-doped graphites, were reduced by the doping, e.g. 5 times and 20% smaller, compared with that for graphite, respectively. The sublimations of the boron and the vanadium were significantly large when the temperature exceeded approximately 1200-degrees-C. The weight loss rate of the doped material to the initial content of the doped material, for example, was approximately 5%/day at 1500-degrees-C for the boron- or the vanadium-doped graphite.