Electron inelastic mean free path measured by elastic peak electron spectroscopy for 24 solids between 50 and 3400 eV

Elastic electron backscattering coefficients have been measured for 24 elemental solids (Ag, Al, Au, Be, Bi, C, Co, Cu, Fe, Ge, Mg, Mn, Mo, Ni, Ta, Te, Ti, Pb, Pd, Pt, Si, V, W, Zn) for energies between 50 and 3400 eV. Values for the electron inelastic mean free path (IMFP) were derived from the experimental intensities on the basis of a simple physical model for elastic backscattering that accounts for bulk elastic and inelastic scattering only. For energies ⩾200 eV the IMFP values were found to be well described by the Bethe equation for inelastic scattering, as found earlier by analysis of optical scattering data with the aid of linear response theory (Surf. Interf. Anal. 21 (1994) 165). The parameters β and γ appearing in the Bethe equation are compared with corresponding results derived from optical data. Both, the parameter β , that is related to the total dipole matrix element for inelastic scattering, as well as the parameter γ , that describes the energy dependence of the IMFP, were found to coincide with the results based on optical data within the experimental accuracy of our analysis. Since the present analysis of electron scattering data is entirely free of linear response theory, the present results may be regarded as an independent test of the previous analysis based on optical scattering data.