Measurements of chemical erosion in the plasmagenerator PSI-1

The stationary plasma of the PSI-1 facility was used for studying the ion energy dependence of chemical erosion of different CFC materials in deuterium plasmas. A weak dependence on the bombarding energy was found having a maximum between 150 and 200 eV. Furthermore, long term exposure experiments with two different CFC materials were carried out showing that the reduction of chemical erosion can be explained by covering the surface with impurities. A study of the contribution of energetic neutrals to erosion revealed effects of the order of 50%; their influence, however, depends on the plasma conditions. (orig.)