Elastic electron scattering cross sections at high momentum transfer

The elastic scattering cross section of keV electrons over large angles (>90°) is discussed. A comparison is made of the Rutherford cross section, the cross section obtained in the first Born approximation and that obtained by a partial wave calculation. The last approach differs significantly from the first two. For compounds, the recoil energy makes it possible to distinguish experimentally from which atom the electron has scattered. We compare the elastic peak ratio of H and O in water at several keV and for Hf and O in HfO2 at 20–40 keV with the calculated ratios. Reasonable (but not perfect) agreement is obtained between the experiment and theory for the partial wave calculations.