Experiment on atomic hydrogen reflection by use of a permeation probe

Experiments on reflection behavior of atomic hydrogen with lower energies were conducted by use of a palladium membrane as a probe for detecting atomic hydrogen. The palladium membrane was exposed to a deuterium rf-plasma, and reflectors were located between them. Hydrogen atoms easily permeated through palladium, which acted as a window for hydrogen atoms. By changing the arrangement of the reflectors of nickel, graphite, glass, tungsten and polytetrafluoroethylene, the corresponding permeation flux was observed, and from which the relative value of the incident atoms to the membrane was estimated. The incident atoms reflected at least once by nickel were nearly the same as those which were reflected more than twice. This indicated that an atomic reflection was very significant. The other reflector materials also showed high atomic reflection. These results may mean that atomic hydrogen is transported for a long distance in openings of structures in fusion devices. (C) 1998 Elsevier Science B.V. All rights reserved.