Photo double ionization of He by circular and linear polarized single-photon absorption

We have measured absolute fully differential cross sections for photo doubl e ionization of helium by circularly and linearly polarized light 20 eV abo ve threshold. The data have been obtained by measuring in coincidence the m omentum vector of the He2+ ion and one of the electrons, covering 4 pi soli d angle for all particles. We give an overview over the momentum distributi on in the three-body continuum and show fivefold differential cross section s. We find a swirl in the electron momentum space for double ionization by circularly polarized light. The present data supersede earlier data from ou r group.