Determination of the absolute differential cross section for the 1$sup 1$S $Yields$ 4$sup 1$S, 4$sup 1$D, 5$sup 1$S, and 5$sup 1$D transitions in helium atoms

The electron--proton coincidence method was used to determine the absolute differential cross sections for electron--atom scattering in helium. These studies were made for excitation of the 4/sup 1/S, 4/sup 1/D, 5/sup 1/S and 5/sup 1/D states which are not resolved by an electron spectrometer; the experiments were performed for incident energies from 50 to 200 eV and for angles of 5 to 20 deg. The generalized oscillator strengths of the transitions studied were obtained from the values of the differential cross sections. (auth)