D. Proulx et R. Shakeshaft, DOUBLE-IONIZATION OF HELIUM BY A SINGLE-PHOTON WITH ENERGY 89-140 EV, Physical review. A, 48(2), 1993, pp. 180000875-180000878
We have calculated the energy and angular distributions for double ion
ization of He by one photon, over the range of photon energies 89-140
eV. Our results compare favorably with experimental data.