Above-surface neutralization of slow N6+ ions during interactions with a Cu(001) target

Measurements are reported for projectile K-Auger-electron emission, observed at 90 degree to the incident beam direction, during interactions of 60-keV N6+ ions with a clean Cu(001) target at grazing incidence angles in the range 0.2 degree--20 degree. Spectral features in the projectile K-Auger-electron spectra consistent with above-surface K-Auger-electron emission were observed at perpendicular velocities below 1.37x10-2 a.u. (incidence angle Ψ<1.9 degree). At incidence angles below 0.8 degree (vperpendicular<5.8x10-3 a.u.) the above-surface K Auger yields were observed to saturate, reaching a maximum value of about 12% of the total K-Auger-electron production. The present results are in good agreement with earlier measurements