The differential scattering cross sections and the generalized oscillator strengths of the 1${\mathrm{}}^1$S→2${\mathrm{}}^1$S and 1${\mathrm{}}^1$S→2${\mathrm{}}^1$P transitions of helium have been measured by angle-resolved electron-energy-loss spectroscopy with an incident electron energy of 1500 eV and within the range 2°–11.5° of scattering angles. The corrections for angular factors and density effects have also been made for the experimental results. The differential cross sections and generalized oscillator strength values are absolute and are the first to be measured at such a high impact energy. The experimental results are compared with other measurements and theoretical calculations in the literature. © 1996 The American Physical Society.

• Received 26 December 1995

DOI:https://doi.org/10.1103/PhysRevA.53.3081