Semi-empirical relationships for the energy loss and straggling of 1-50Â keV hydrogen ions passing through thin carbon foils

Thin carbon foils are used in many fields of physics, including for the detection of keV particles in space plasma instrumentation. The interaction of ions or neutral atoms with these foils results in different effects: electron emission, charge exchange, angular scattering, and energy loss and straggling. We report measurements of the energy loss and straggling and angular scattering of 1-50 keV protons for different foil thicknesses (nominal 0.5-2.0 μg/cm2). We derive simple semi-empirical relationships for the energy loss and straggling as a function of incident energy and foil thickness. We also derive a semi-empirical relationship between the derived thickness and the scattering constant. This provides a simple and straightforward tool to estimate the energy loss by measuring the angular scattering of protons for a particular foil.