K-Shell Vacancy Production in Light-Element Atoms with α Particles and N⁷⁺ Ions of 5, 6, and 7 MeV/amu

Abstract

K-shell ionization cross sections of five elements in the range from Ca to Cr have been measured for α-particle and N⁷⁺-ion bombardments at projectile energies of 5, 6 and 7 MeV/amu. Contributions from the binding energy effect, the polarization effect and the electron transfer effect to these inner-shell ionization are investigated. From the (Z_p⁄Z_s)-dependence of the inner-shell ionization cross section, where Z_p is the projectile charge and Z_s is the effective atomic number of target atoms, it is found that the binding energy effect and the polarization effect cancel out each other in the present impact-energy region and the charge-transfer cross section is proportional to (Z_p⁄Z_s)⁵.