Absolute triple differential cross sections for photo-double ionization ofhelium - experiment and theory

We have measured absolute triple differential cross sections for photo-doub le ionization of helium at 20 eV excess. The measurement covers the full ra nges of energy sharing and emission angles of the two photoelectrons. We co mpare our data for selected geometries with the convergent close-coupling ( CCC) calculations as well as 2SC calculations by Pont and Shakeshaft and 3C calculations by Maulbetsch and Briggs. In terms of the absolute magnitude and the trend in the shapes of the triple differential cross section for di fferent geometries we find good agreement of the CCC and published 2SC calc ulations with our measurement, though differences with respect to the obser ved shape of individual patterns still exist.