Electron Irradiation of Gold Below 2 K

Abstract

Gold (99.9999% purity) was irradiated by 2.5-MeV electrons below 2 K. Damage production was monitored by measuring the dc resistivity of the gold. The production rate dρdΦ (change in resistivity per integrated electron flux) was found to (a) be enhanced by the presence of quenched vacancies at extremely low values of integrated flux, (b) be attenuated by the presence of quenched vacancies at higher values of integrated flux, (c) decrease with increasing Φ particularly at the lowest values of Φ, and (d) increase with increasing dΦdt (beam flux). Thermal recovery of resistivity was observed as low as 2.3 K. The recovery in the range 2.3-30 K was found to (a) be enhanced by the presence of quenched vacancies, (b) be attenuated by the presence of silver impurities, and (c) increase with increasing Φ. These observations are consistent with the hypothesis that the interstitial in gold undergoes long-range migration either during electron irradiation at 1.7 K or during annealing at 1.95 K.