Monochromator optics for sub-meV resolution

Scientists at Argonne National Laboratory, USA have recently reported a novel set of optics for X-ray monochromators, which combine the effect of angular dispersion and anomalous transmission of X-rays in Bragg reflection from asymmetrically cut crystals. The optics employ a five-reflection, three-crystal arrangement, and it was found that the spectral contrast, the bandwidth and the angular acceptance are approximately 500, 0.5 meV, and 0.1 mrad, respectively, for 9.1 keV X-rays. The new optics could be a foundation for next-generation inelastic X-ray scattering spectrometers. For more information, see the paper, "Using angular dispersion and anomalous transmission to shape ultramonochromatic x rays", Y. Shvyd'ko et al., Phys. Rev. A84, 053823 (2011).