Fast- and Thermal-Neutron Irradiation and Annealing of Cu, Ni, Fe, Ti, and Pd

Abstract

Concentrations of lattice point defects produced by thermal-neutron and fast-neutron irradiation of copper, nickel, iron, titanium, and palladium at 4.5$sup 0$K were measured resistometrically, and the values are compared with the theoretically predicted values. For thermal-neutron irradiation the ratio of the predicted to measured concentration of defects ranged from a minimum of 1.0 for titanium to a maximum of 4.5 for palladium; for fast-neutron irradiation this ratio ranged from 2.3 for titanium to 6.5 for copper. On postirradiation isochronal annealing no stage II or V are present in copper after thermal-neutron irradiation, but both these stages are present after fast-neutron irradiation. Both nickel and titanium exhibit more than 100 percent recovery, super-recovery, after thermal-neutron irradiation. The super-recovery is attributed to the irradiation-induced supersaturation of vacancies that provide the enhanced diffusion required for the precipitation of impurity atoms from the lattice. Little or no enhanced diffusion is observed after fast-neutron irradiation of nickel and titanium. (auth)