Spreng and his co-workers1have studied radiation enhanced diffusion in gold-silver alloys at low temperatures. Their research technique consisted in analysing the decrease in amplitude of short wavelength composition modulations produced in film samples under irradiation with an electron current of 1.2 · 1013cm−2sec−1at 2 MeV at 77°K. The decrease in amplitude thus discovered, has been attributed to diffusion due to free migration of interstitials to sinks; consequently, the above effect seems to prove the existence of free migration of interstitials at temperatures of the annealing stages I and II for radiation defects.