ID-IErecovery in electron irradiated copper. I. Experimental

The ID-IE region (30 K–60 K) was studied using sequential isothermals following irradiation near 4.2 K, as a function of electron energy, Ee , and initial defect concentration, Ci. Resistivity was monitored almost continuously, and end point measurements were made at 4.2 K to correct for deviations from Matthiessen's rule. Using temperature-compensated (equivalent) annealing times, obtained with the factor exp{−[(0.117 ± 0.003 eV)/kT]}, isothermal sections were joined to yield densely populated extended recovery profiles. The recovery is strongly Ee -dependent for Ee ∼ 0.5 MeV, only slightly between 0.6 and 1.4 MeV. The Ee -dependence is consistent with a model in which i-v pairs of large separations are produced in or near<110> directions. I D is independent of Ci . The Ci -dependence of IE requires i-i and i-impurity interactions. A three-dimensional model is fit to the 0.6 MeV data at 2, 7, and 25 ppm point defect concentration, using a Gaussian separation distribution having a mean separation of 1.6 capture radii.