Electron microscope observations of irradiated graphite single crystals

摘要: Abstract Graphite single crystals have been studied by dark field transmission electron microscopy after irradiation with fast neutrons between 5.2×l0 17 and 1.5×10 20 n/cm 2 at temperatures below 150°C. Subsequent annealing has investigated up to 2000°C. For comparison, specimens irradiated electrons, C 12 -ions fission fragments studied. Contrast effects calculated means of the kinematical theory diffraction. The distribution vacancies was a surface etch decoration technique. All observations are compatible assumption primary formation independent interstitials subsequent clustering only interstitials. Only small fraction these clusters can be resolved microscopy; contain about 1 per cent originally displaced atoms. At dose above 10 more complex phenomena observed.