40 keV Ne, A, Kr and Xe ions have been used to bombard Ge single crystals at perpendicular incidence to (110) under clean target conditions. The temperature, dose and dose rate dependences of the accumulation of disorder have been determined. In a low temperature interval, 50–150°C, small temperature and dose rate effects on the accumulation of disorder were detected for Ne and A but for the other ions there was no such dependence. At temperatures above 150°C the temperature and dose rate for all types of ions used influence the accumulation of disorder. Different temperatures for the transition from a crystalline to a disordered region were detected for the various dose rates and ions used. Activation energies of 1.45 ± 0.15 eV for the observed defects have been calculated.