Emission of secondary particles from metals and insulators at impact of slow highly charged ions

The emission of secondary electrons and ions from clean Au, CxHy-Au and SiO2 surfaces at impact of slow (upsilon approximate to 0.3 upsilon(Bohr)) ions has been measured as a function of incident ion charge for 1 + less than or equal to q less than or equal to 75 +. Electron yields from thermal silicon dioxide films (150 nm on Si) are found to be lower than those from Au and CxHy-Au for q > 3 +. Yields of negative secondary ions from SiO2 and CxHy-Au were recorded in parallel with electron emission data and exhibit a q(n), n approximate to 4, dependency on incident ion charge. A direct comparison of collisional and electronic contributions to secondary ion production from SiO2 films using a beam of charge state equilibrated Xe-q=qeq (at 2.75 keV/u) shows positive and negative secondary ion yield increases with incident ion charge of > 400. Results are discussed in relation to key signatures of electronic sputtering by Coulomb explosions.