Stopping power of solid targets for slow helium ions

The energy loss of slow helium ions interacting with different solid targets is determined experimentally. By using a phase-shift sum rule for the amplitude of the dipolar backflow current, a consistent screened potential of these projectiles in an electron gas is constructed and applied to the kinetic model of stopping. The theoretical description reproduces well the experimental data over a broad range of the effective electron density including the accessible dilute limit. The combined theoretical and experimental analysis results in a consistent physical picture for the stopping of slow helium ions in solids.