Electron Irradiation of Copper and Aluminum above Stage I

The dependence of the increase of electrical resistivity upon integrated electron flux $\varphi$ has been investigated in copper and aluminum. Irradiations were performed at 80°K using 1.1-MeV electrons. The resistivity was found to increase nonlinearly with $\varphi$ up to the highest fluxes used: ${10}^{19}$ electrons/${\mathrm{cm}}^2$. At high $\varphi$ values, the increase in resistivity appears to be proportional to ${\varphi }^{\frac{1}{2}}$. This dependence is predicted in a model in which interstitials, created during irradiation, are primarily annihilated by recombination with vacancies created concurrently during irradiation, but may alternatively be trapped by intrinsic defects such as impurities or dislocations.