Investigation of hydrogen stopping in noble metals around the stopping power maximum

Abstract

The stopping cross sections of copper, silver and gold for protons and deuterons were measured in the energy range from 50 keV/amu to 500 keV/amu. All measurements were performed on supported films evaporated onto polished backings employing both transmission and backscattering type techniques. By use of different hydrogen isotopes — assuming velocity scaling — and of different target thicknesses we showed that plural and multiple scattering do not influence our results within the experimental uncertainties of ± 3%. As a cross check the stopping ratios were also measured by evaluation of the heights of the backscattering spectra and were found to be consistent with the absolute values. Our results are compared to the theory of Lindhard-Winther using different solid state charge distributions and to the binary encounter theory of Kührt and Wedell. Best agreement is achieved for those calculations which take the correct density of the valence electrons into account. Furthermore, our results are compared to the fitted data by Andersen and Ziegler (1977), by Janni (1982) and by Ziegler (to be published). In general, better agreement with the more recent fit-data was found.