The nucleation of radiation damage in graphite

摘要: Abstract A quantitative survey has been carried out of the sizes and densities defects found by transmission electron microscopy irradiated graphite crystals. Three regimes are considered, viz. isothermal irradiations between 150° 1200°c, seeding in which crystals have given a short pre-irradiation at lower temperature before irradiation, behaviour during thermal annealing. In each regime comparison made with corresponding macroscopic property changes observed on polycrystalline material. This behaves like added traps about 0·37 ev depth, causing heterogeneous nucleation interstitial clusters, density one per crystallite plane. The vacant lattice sites an energy 5·5 ± 1 ev, only half that predicted recent theoretical calculations. Interstitial loops migrate conservative climb process activation 2·6 is reduced to 1·8 presence continued ...