KINETIC ELECTRON-EMISSION YIELD INDUCED BY H+ AND HE2+ IONS VERSUS STOPPING POWER FOR AL, CU, AG AND AU

For H+ and He2+ ions impinging on Al, Cu, Ag and Au targets we measured simultaneously the yield, gamma, of emitted electrons and the electronic energy loss, S(e), in the energy range 0.5 to 4.8 MeV. The targets were prepared under high-vacuum conditions before they were transferred to an ultra-high-vacuum chamber without breaking the vacuum. The targets were sputter cleaned and their composition was examined by Auger electron spectrometry. The values of gamma were obtained by current integration and S(e) was determined from the energy width of Rutherford backscattering spectra. For H+ ions impinging on Cu, Ag or Au and He2+ on Al and Cu, the expected proportionality between gamma and S(e) was found within the experimental errors of 2%. For H+ ions on Al and He2+ ions on Ag and Au targets, significant deviations were observed.