Scattering configuration together with phase plates and polarization analyzer. The phase plates allow a rotation (η) of the linear incident polarization in the plane normal to the incident wavevector as well as generation of left and right circular polarization. For the sample the scattering vector Q and the uniaxial vector z is shown, which rotates around Q with the azimuth angle Ψ in the plane normal to the scattering vector. At the sample the reference vectors , and are shown (Blume & Gibbs, 1988). The scattered signal is analyzed by the polarization analyzer, which can be rotated by the angle around the scattered beam. By rocking the analyzer at several different , the polarization properties of the diffracted beam can be determined. Polarization components perpendicular, σ (σ′), and parallel, π (π′), to the diffraction plane are shown for the incident (diffracted) X-ray beam.