Search for Fermi shuttle mechanisms in electron emission from atomic collision sequences

Abstract In electron spectra induced by slow heavy ion bombardment of solids a high energy tail can be observed, which is suggested to be explained by multiple collision sequences. In order to find those multiple collision effects like the “Fermi shuttle” acceleration mechanism we measured doubly differential electron emission cross sections for H + (33.5–700 keV) impact on different targets (He, Ne, C and Au) as a function of projectile energy and electron emission angle. We observed a surprising target dependence of the electron emission within the range of electron energies close to that of the binary encounter electrons for all observed angles of emission.