The controlled preparation of low SEE surfaces by evaporation of metal films under high residual gas pressures

Abstract

It is shown that surfaces with low secondary electron yield (less than 1) can be prepared by evaporating metal films in a relatively high residual gas pressure. Yield measurements in the energy range 75-2000 eV have been made on surfaces prepared by evaporating gold, silver and copper at residual gas pressures of 05 torr in the gases H₂, He, N₂ and Ar. These surfaces are found after outgassing in uhv to have considerably lower yields and back-scattering coefficients than the pure metals. The rate of evaporation is shown to be an important parameter modifying the microscopic surface geometry. Scanning electron micrographs of some of the surfaces are presented showing the morphology. The results cannot be explained entirely in terms of geometrical factors.