The accumulation of point defects in crystalline material under irradiation was studied by using classical molecular dynamics simulations. Collision cascades were simulated by starting from randomly chosen primary knock-on atoms, with energies of between 50 and 500eV, at various temperatures. It was found that, in agreement with experiment, simulated electron irradiation at low temperatures failed to cause amorphization. On the other hand, ion bombardment resulted in the formation of amorphous material. It was concluded that the threshold recoil energy which was required for amorphization at low temperatures was between 50 and 200eV.

D.M.Stock, G.H.Gilmer, M.Jaraiz, T.Diaz de la Rubia: Nuclear Instruments and Methods in Physics Research B, 1995, 102[1-4], 207-10