  Polarization characteristics of the gamma beam obtained by the Compton back
scattering of laser photons on high energy electrons are evaluated by
Monte-Carlo simulations.
  It is assumed that outgoing photons are tagged; the energy dispersion of the
tagging photons and emittance of the initial electrons are taken into account.
Dependence of the final photon polarization parameters on measured photon
energy is obtained. It is shown that polarization of final photons is
decreasing with change for the worth of the tagging energy resolution.
Calculations have been applied for the storage ring SIBERIA-2 at Kurchatov
Institute. The obtained results indicate a reasonability for construction of
gamma-polarimeters on existing and planned facilities for the on-line
measurement of the final photon beam polarization.
