A NOVEL ULTRAHIGH-RESOLUTION MONOCHROMATOR/ANALYZER SYSTEM FOR AN INELASTIC X-RAY SCATTERING SPECTROMETER WITH 26 PRECISION POSITIONING STAGES

摘要

Many important scientific topics related to the high-frequency dynamics of condensed matter require both a narrower and steeper resolution function and access to a broader dynamic range than are currently available. There are needed for the development of a new inelastic x-ray scattering (IXS) spectrometers with improved energy and momentum resolution. Three effects in Bragg diffraction of x-rays in backscattering geometry from asymmetrically cut crystals have been observed by Yuri Shvyd'ko et al. in 2006 [1]: (1) Exact Bragg backscattering does not take place at normal incidence to the reflecting atomic planes. (2) A well-collimated beam is transformed after the Bragg reflection into a strongly divergent beam with a reflection angle dependent on the x-ray wavelength (an effect of angular dispersion). (3) Parasitic Bragg reflections accompanying Bragg backreflection are suppressed. These effects provide a radically new method for monochromatization of x rays not limited by the intrinsic width of the Bragg reflection. However, there are many optomechanical design challenges on the road to turning a CDDW optical configuration into a practical instrument [1-5].