  The full exploitation of the physics potential of an International Linear
Collider (ILC) requires the development of a polarized positron beam. New
concepts of polarized positron sources are based on the development of
circularly polarized photon sources. The polarized photons create
electron-positron pairs in a thin target and transfer their polarization state
to the outgoing leptons. To achieve a high level of positron polarization the
understanding of the production mechanisms in the target is crucial. Therefore
a general framework for the simulation of polarized processes with GEANT4 is
under development. In this contribution the current status of the project and
its application to a study of the positron production process for the ILC is
presented.
