ELECTRONIC STOPPING CROSS-SECTIONS OF 50-300-KEV HE AND LI IONS

For 50-300-keV He+ and Li+7 in C, Al, Cu, Ag, and Au, the applicability of the simplified stopping function is investigated. Using the same targets for He+ and Li+ the electronic stopping power Se in 400-800- foils is measured by means of a magnetic spectrometer. The resulting stopping fractions Se(Li)Se(He) can be evaluated to an error of 2%. At energies above 20 keV/amu they are found to be independent of the target material. Applied to our experimental data, the simplified stopping function is shown to be a good approximation in connection with the fits of Andersen-Ziegler for Se (H) and the stopping ratios. © 1979 The American Physical Society.