Determination of target mass from ISS data in the presence of inelastic losses

Ion scattering spectroscopy (ISS) is often used to identify the masses of surface atoms through measurement of scattered-ion energies. Mass analysis is straightforward when the scattering events can be described by binary elastic collision kinematics. However, inelastic and multiple scattering effects can alter the final energy of the detected particles, complicating the analysis. Here we present a method that uses ISS data collected at two or more observation angles to identify both the mass of the scattering center and any inelastic energy loss. Use of this technique can also allow detection and quantification of certain systematic errors, such as uncertainties in the initial beam energy, detected ion energy and scattering angle. While ion scattering is stressed here, the presented technique works equally well for the analysis of direct recoil ion energies. An example using He+ ISS data recorded on an Al–Ag alloy illustrates the abilities of this method.