M-shell ionization in gold by light ions

Abstract

M-shell X-ray production cross sections for Au targets have been measured by 1H, 3He and 4He ions in the energy range 0.6–4.0 MeV. The Si(Li) detector efficiency in the low-energy X-ray region (1.5–4 keV) was carefully determined using the PIXE method. The elastically scattered projectiles were detected by a surface-barrier detector to normalize X-ray yields. The measured X-ray yields were converted to M-shell X-ray production cross sections and then, using average M-shell fluorescence yields evaluated according to relativistic calculations of Chen et al., the total M-shell ionization cross sections were derived. The experimental M-shell ionization cross sections are compared with results reported by other authors and with the predictions of the first-order theories, namely, the PWBA and SCA approximations and also the ECPSSR theory, which accounts for energy-loss, Coulomb deflection, binding-polarization, and relativistic effects.