Measuring polarization of high-energy gamma rays

A method to determine the polarization of incident gamma-ray in two energy ranges is presented. The method consists basically in the determination of the asymmetry in the azimuthal distribution of the scattered radiation, in the energy range where Compton scattering dominates, and in the measurement of the asymmetric angular distribution of the e± pair in the pair production regime. We show that the definition of the asymmetric ratio is a useful concept to determine polarization.