(gamma, 2e) in He - A practical parametrization of the triple differentialcross section

Several model functions capable of representing the symmetrized transition amplitudes within the parametrization formalism of Huetz et al for the phot odouble ionization of helium are proposed. The model is based on the well d ocumented features of the gerade transition amplitude in the cases of symme tric energy sharing and/or small excess energies. Those are extended toward s the higher excess energies and for an arbitrary energy sharing, where bot h the gerade and the ungerade components of the transition matrix contribut e, with a minimum of modifications. Excellent agreement between a sample of experimental and theoretical triple differential cross sections (TDCS) ext ending up to 40 eV on one side and the parametric form on the other is obta ined by using just three adjustable parameters which could be reliably extr acted from most experiments. This creates the possibility for a complete dy namical parametrization of the TDCS in the low to intermediate excess energ y range.