Energy loss of low energy Hydrogen and Helium ions in light gases

The knowledge of stopping power in various combinations of ions and targets over a wide range of energies is necessary to extract the fundamental interaction cross section from measured yields in nuclear reactions. While, for many years, energy loss data has been measured, tabulated and incorporated in semi-empirical codes, specifically at low energies and for gaseous targets only few experiments have been performed. In this work, stopping power data of Hydrogen and Helium ions in the energy range below 25 keV traversing light gases were determined. Special emphasis was put on the energy loss of Hydrogen in Helium where a previous discrepancy between two publications was resolved and the range of measurement extended to the energies where the influence of nuclear stopping becomes apparent.