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Secondary Electron Emission from Metal Targets under Heavy Ion Bombardment

1982; Institute of Physics; Volume: 21; Issue: 4R Linguagem: Inglês

10.1143/jjap.21.586

1347-4065

Akio Kôyama, T. Shikata, Hideo Sakairi, Eiichi Yagi,

X-ray Spectroscopy and Fluorescence Analysis

The secondary electron emission coefficients γ for in-situ vacuum-deposited Al, Cu, Ag and Au targets were measured under bombardment with He 2+ , C 4+ , C 6+ , N 4+ , N 5+ , N 7+ , O 5+ and O 8+ ions in the energy region of 4.5–8 MeV/amu. The ratio between γ and the electronic stopping power S increases with the incident energy. The energy dependence of γ is insensitive to the variation of the projectile charge state. The square of the effective charge Z 2 eff ( z 1 , c ; Z 2 ) of a projectile with atomic number Z 1 and electric charge c in the thin surface region of the target with atomic number Z 2 is obtained. Z 2 eff ( z 1 , c ; Z 2 ) expresses the projectile charge state dependence of γ, and is equal to ( z 2 1 + c 2 )/2+( z 1 - c )+α( z 1 - c ) Z 2/3 2 . α is a numerical factor and is 0.16 for N 4+ ions.