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

K-shell ionization cross sections of five elements in the range from Ca to Cr have been measured for a-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 tothese inner-shell ionization are investigated. From the (Zp/Zs)-dependence of the inner-shell ionization cross section, where Zp is the projectile charge and Zs 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 (Zp/Zs)5.