Multiple ionization effect of Au induced by different ions

Abstract

We report the experimental data of characteristic X-ray spectra produced by the impact of H⁺, Ar⁸⁺, Ar¹²⁺, Kr¹³⁺ and Eu²⁰⁺ ions with different kinetic energies on Au surface in the National Laboratory of Heavy Ion Research Facility in Lanzhou, China. The energy shifts of X-ray spectra are analyzed and the ratio of X-ray yield is calculated. The results show that H⁺ can excite the characteristic X-ray spectra of M_ζ and M_α of Au, while Ar⁸⁺, Ar¹²⁺, Kr¹³⁺ and Eu²⁰⁺ can excite the characteristic X-ray spectra of M_ζ, M_α, M_γ and M_δ of Au, because the inner shells of target atom are multiply ionized by heavy ions impact, so that the relative intensity ratio of the X-rays changes when the heavy ions are incident. There are different energy shifts of Au M X-ray due to multiple ionization effect in collision. When the ion incident energy is lower, the degree of multiple ionization of the inner shells of the target atom is almost independent of the incident energy, when the ion energy is higher, the degree of multiple ionization increases with incident ion energy increasing. At the same time, the degree of multiple ionization also depends on the number of holes in the outer shell of the ion and its atomic number. That the ratio of X-ray yield increases with the increase of the atomic number of the incident ion further indicates that the degree of multiple ionization increases with atomic number of the incident ion increasing. The multiple ionization and electron configuration of the inner shells of the atom can be determined by the energy shift and spectra broadening. These measurements provide basic data for further studying the multiple ionization mechanism of the inner shells of the atom. But due to the limitation of the resolution of the detector, the spectral broadening data cannot be measured. It is necessary to use a higher-resolution detector to further study the multi-ionization effect of the inner shells of the atom.