Hard X-ray polarimeters based on symmetric, asymmetric and dispersive channel-cut crystals

Abstract The polarization characteristics of synchrotron radiation are widely used in scientific research. In recent years, linearly polarized X-rays with extremely high purity can be obtained by high-precision polarimeter based on the repetitive reflections at Brewster angle of the channel-cut crystals. Here, we report on polarimeters based on different types of channel-cut crystals which are symmetric, asymmetric and dispersive respectively. The experiments were performed on a bending magnet beamline at Shanghai Synchrotron Radiation Facility. The polarization purity of the Si(800) diffracted beam from symmetric channel-cut crystals with a center energy of 12.914 keV can reach 4.1×10 −9 under 2.4 Torr vacuum degrees, which is mainly limited by the brightness of the bending magnet light source.