Single crystals of Ge (110) were bombarded by 40 keV Ge ions at a dose rate of 6.0 × 1013ions/cm2sec in the temperature region 50–500°C. The secondary electron emission yield was used to study the state of disorder. In accordance with Chadderton's damage center nucleation model the growth of disorder can be divided into several dose intervals. Radiation enhanced and thermal annealing characteristics have also been studied using a probe ion beam of dose rate 6.0 × 1011ions/cm2sec. Evidence for both bombardment enhanced and thermal annealing are established. The bombardment enhanced annealing of a continuous disordered layer occurs at the inner region of the layer. The temperature dependence of the bombardment enhanced annealing indicates that a thermal step is included in the annealing process.