Low temperature electron irradiation and annealing of pure cadmium. [Electrons below 2/sup 0/K]

Cadmium after electron irradiation below 2/sup 0/K, was studied and the damage production rate in Dc was found to be (4.13 +- .16) x 10/sup -26/ ..cap omega..cm/(e/sup -//cm/sup 2/) for irradiation with 2.5 MeV electrons at 1.5/sup 0/K. New annealing peaks were observed at 1.825/sup 0/K and at about 2/sup 0/K with activation energies of (2.6 +- .1) x 10/sup -3/ eV and (2.77 +- .34) x 10/sup -3/ eV, respectively. The peak at about 2/sup 0/K exhibits dose-dependence, but it is better described by first order kinetics; this peak is believed to correspond to the long-range migration of the self-interstitial, preferentially to impurities where they form clusters. It has been found that subthreshold irradiation results in the annealing of damage already present. This radiation annealing effect may be a contributing factor to the seesaw effect. Another physical process may contribute to the seesaw effect, namely, the trapping of interstitials at impurities and their subsequent detrapping during annealing.