Surface morphology changes of graphite irradiated with energetic helium ions

Implantation of helium ions into graphite has been found to produce surface features, which are discussed in terms of radiation damage as a function of depth into the material. Annealing and electron microscope studies show these surface features to be still well defined after annealing at 15000C. The suggested interpretation is consistent with the large surface stress found in the surface layers of implanted materials. (author)