Measurements of energy loss spectra of positrons scattered from solid surfaces

Abstract

Surfaces of tungsten and silicon were bombarded with monoenergetic beams of positrons and electrons, and spectra were recorded for particles scattered at shallow angles with respect to the incoming beam. For both positrons and electrons discrete energy loss peaks were observed at kinetic energies about 15 eV lower than that of the elastic peaks. For energy losses greater than 15 eV the positron spectra were significantly different from the electron spectra; for tungsten the relative intensities for positrons were higher and the spectra showed different structure. In this letter we report the first experimental measurements of positron energy losses from solid surfaces. We have demonstrated that such experiments are practical and that it is feasible to explore their use for surface analysis.