Ionization of the AluminumKShell by Low-Energy Hydrogen and Helium Ions

The yields for characteristic $K$-shell x rays in aluminum are measured as produced by ${\mathrm{H}}^1$, ${\mathrm{He}}^3$, and ${\mathrm{He}}^4$ ions in the energy range 25-200 keV. The ionization cross sections deduced from these data are in detailed agreement with the theory, if the Coulomb deflection of the incoming particle by the target nucleus and the binding of the $K$-shell electrons to the incoming particle are included in the Born approximation.