High Energy Sputtering from Cleaned Metal Foils

Positive and negative secondary ions desorbed from metal foils by bombardment with 252Cf fission products have been investigated by time-of-flight mass spectroscopy. The measurements were performed under UHV conditions using metal foils of Cu, Ni and Al cleaned by Ar-ion etching. Spectra were taken with cleaned surfaces and also under the exposure of H2 , O2 , N2 , CO, C2H4 , C2H6 and C3H7OH up to several 100 L. The yields of metal ions from clean metal surfaces are in agreement with Sigmund' theory.