Experiment on first-wall carbon coating: Focusing hydrogen concentration

As a back-up experiment for investigations on first-wall carbon coatings of toroidal machines, we constructed the RIKEN ECR-2 device and carried out simulation experiments. By electron cyclotron resonance discharges we obtain an amorphous, hard, and dense carbon film. It is possible to decrease the atomic H/C ratio of carbon films by high-energy ion bombardment. Harmful carbon films deposited on observation windows can be cleaned up by a local pure hydrogen plasma.