Bombardment of Tungsten with 20‐keV Helium Atoms in a Field Ion Microscope

摘要

Fast He atoms are shot into one side of the tungsten emitter tip of a field ion microscope, and the resulting damage to the surface, consisting of vacancies, interstitials, and their clusters, is observed in atomic resolution. About one‐half of the number of atoms calculated to have received a displacement energy of 50 eV in the interior appear as surface defects. The surface integrates the damage by focusing collisions coming from as deep as 1000 Å. Stress enhanced mobility of subsurface interstitials is detectable at 21°K, and rapid thermal diffusion from the depth occurs at 90°K.