Characterization of an X-ray diamond phase plate by a polarization analyzer using multiple diffraction

X-ray transmission phase plates are widely used to control the X-ray polarization at many synchrotron facilities. Although their performance can be calculated from the dynamical theory of X-ray diffraction, it is sometimes necessary to measure the produced polarization for a precise analysis of experimental data. To meet this requirement, we have combined two types of X-ray analyzers: a linear analyzer based on 45° Bragg diffraction and an analyzer based on multiple diffraction. The former was used to adjust a diamond phase plate and the latter for a complete determination of the produced polarization. We successfully obtained elliptically polarized X-rays and determined the Stokes parameters at the vertical-wiggler beamline BL-14B of the Photon Factory. The obtained degree of circular polarization was -0.70 and 0.95.