Production and Recovery of Electron-Induced Radiation Damage in a Number of Metals

Abstract

The changes in residual electrical resistance produced by bombardment with high-energy electrons were measured for a number of metals as a function of electron energy in the range from 0.5 to 1.4 MeV. The irradiations were performed at ≲20°K, and recovery measurements were made up to 300°K. The production curves were analyzed using simple displacement theory and the following values were found for the average threshold energies: Al, 32 eV; Au, >40 eV; Ag, 28 eV; Cu, 22 eV; Fe, 24 eV; Mo, 37 eV; Ni, 24 eV; Ti, 29 eV; and W, >35 eV. Approximate values for the resistivities of Frenkel pairs (in units of μΩ cm per at.%) were also obtained as follows: Al, 3.4; Ag, 1.4; Cu, 1.3; Fe, 12.5; Mo, 4.5; Ni, 3.2; and Ti, 42. In the case of Al it was necessary to take secondary defect production into account and a number of representative theoretical curves, based on different assumptions concerning the process of secondary defect production, are included. The behavior of Zn was anomalous in that the added resistivity was not a linear function of electron dose at 20°K.