BEAM-FOIL CONVOY ELECTRONS EMERGING FROM UNCLEANED AND CLEANED SURFACES IN COINCIDENCE WITH CHARGE-ANALYZED PROJECTILES INCLUDING NEUTRALS

We discuss measurements of convoy electrons performed with incident H (50, 150 keV) and He+ (100, 200, 400 keV) ions, in coincidence with c harge-analysed projectiles emerging from thin (150-250 Angstrom) C and Cu foils. A strong dependence of convoy electron yields on the projec tile charge, as well as cusp-electron spectra in coincidence with neut rals are observed and compared with the characteristics of presently a vailable models for beam-foil convoy electron emission. Measurements p erformed with sputter-cleaned target surfaces confirm that the transmi ssion through the surface potential is important in determining both t he coincident convoy electron yields and the final charge distribution of the emerging projectiles.