The correlation between inelastic energy loss and scattering angle in transmission experiments

We measure the energy loss as a function of the emergence angle, and the angular spread as a function of the energy loss for 50-200 keV H ⁺ and He ⁺ on 410 Å C and 170 Å Al foils. A strong dependence of the angular spread on the energy loss has been observed, as well as an angular dependence of the energy loss far beyond that predicted by path length enlargement and nuclear stopping power. Theoretical expressions for the previous magnitudes were obtained on the basis of a multiple scattering formalism and a single collision energy loss-scattering angle function Q( θ). In addition, a procedure is presented to retrieve this Q-function from the experimental data.