M-X-ray production cross sections of heavy elements by charged-particle impact

The M-subshell ionization cross sections of heavy elements by proton and helium-ion impact have been calculated in the binary-encounter approximation. The momentum distribution of target electrons is taken into account by the use of the nonrelativistic and relativistic hydrogenic models and the Hartree-Fock-Roothaan method. The obtained subshell ionization cross sections are converted into the M-X-ray production cross sections and compared with experimental data and other theoretical calculations. The electronic relativistic effect and the wave-function effect on M-shell ionization cross sections are studied and possible reasons for large discrepancy between theory and experiment for Mγ-X-ray production cross section are discussed.