Proton stopping cross sections for carbon,aluminium and gold: New experimental data and critical analysis of the validity of empirical fit formulas

We report new experimental data for the stopping cross section S of protons in carbon, aluminium and gold at energies between 8 and 300 keV. The data are found to exhibit largely the same energy dependence as previously reported data. Using empirical fit functions we have analysed available experimental data in terms of the ratios S_exp/S_fit from which we derive scaling factors b applicable to various sets of experimental data. These scaling factors, which typically range from 0.9 to 1.1, are attributed to deviations of the true foil thickness from the assumed one. Using b-corrections all sets of experimental data can be adjusted to fall on the same target specific stopping power curve (maximum deviation ± 3%). While the adjusted data are well described by the respective fit function (A1: Andersen and Ziegler) or tabulation (Au: Janni) the empirical data for carbon apparently deserve further improvements.