Heavy-ion induced damage of crystalline Ge and W in the 0.5-8 MeV range

High energy heavy-ion induced damage of Ge and W crystals was studied by blocking and channeling. Beams of ions from C to Au with energies from 12 to 266 MeV were used both for damaging the crystal and for "in-situ" measurement of lattice disordering. The blocking minimum yield and angular half-width have been measured as a function of dose, and it is shown that the relative ion damaging efficiency for Ge decreases at high electronic energy-loss values. The mechanism of microannealing along the ion path is discussed. The saturation and dose-rate dependence of damage are explained in terms of defect mobility and recombination processes. For a W crystal the initial damaging power is proportional to the number of displacements predicted by TRIM and a disorder saturation is observed at high doses.