Double ionization of helium by fast electrons

The first Born approximation cross sections for electron double ionization of He are calculated using a 12-term partial-wave expansion, correlated wave function for the ground state and symmetric products of the Sommerfeld integral representation of the Coulomb positive energy function for the final state. The results are compared with two existing sets of experimental values and a scaled proton calculation of He++. The agreement between theory and one set of experimental values is excellent for incident electron energies above 4 kev.