A spectrometer has been designed and built for the study of electron-i
on scattering. The angular distribution obtained with this instruments
for the elastic scattering of electrons from Na+ ions at 10 eV is pre
sented. The measurements clearly demonstrates interference effects, de
viating markedly from the Rutherford formula, and are in good agreemen
t with the results of phase-shift calculations based on semiempirical
potentials.