Displacement Cross Sections for Fast Electrons Incident on Gold

Abstract

The displacement cross section for electrons producing radiation damage in solids has been computed, using the Mott series for relativistic Coulomb scattering. The results are compared with the widely used formula of Seitz and Koehler, based on a low-$Z$ approximation due to McKinley and Feshbach. For low-$Z$ elements, the formula of Seitz and Koehler was found to be accurate. For gold the displacement cross section computed from the Mott series is, in the region of 2-4 MeV bombarding energy, about twice as large as the value obtained from the approximate formula. The behavior of the cross section near threshold and at very high energies has been considered. For high-$Z$ values the displacement cross section shows predominantly a parabolic rise near threshold. At very high energies it falls slowly toward a finite value. The implications of these calculations for various experiments on radiation damage in gold are briefly discussed.