Experimental investigation and phase shift analysis of low-energy electron-helium scattering

The angular distribution of electrons scattered elastically from helium atoms has been measured in the energy range from 2 to 19 eV. The experimental data have been fitted by the partial wave formula to determine the scattering phase shifts. From these, absolute values of the differential and the total cross sections were computed. The accuracy of the measured shape of the angular distributions is better than 5%, of the absolute calibration between 20% at low and 5% at high energies. The discrepancy between earlier experiments and theoretical predictions is removed in favour of theory.