Angular Distributions of Electrons Ejected from Helium by Proton Impact

Angular distributions of electrons ejected from helium by proton impact are calculated in the plane-wave Born approximation using bound and continuum electron wave functions obtained from a Hartree-Fock potential. The results of this calculation are compared with experimental data and good agreement is found when the relative electron-proton velocity is larger than the proton velocity. The good agreement observed for large angles of the ejected electron is to be contrasted with previous calculations, which fell lower than the large-angle-scattering experimental data.