110 research outputs found

    A split and delay unit for the European XFEL

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    For the European XFEL [1] an x ray split and delay unit SDU is built covering photon energies from 5 keV up to 20 keV [2]. This SDU will enable time resolved x ray pump x ray probe experiments as well as sequential diffractive imaging [3] on a femtosecond to picosecond time scale. Further, direct measurements of the temporal coherence properties will be possible by making use of a linear autocorrelation. The set up is based on geometric wavefront beam splitting, which has successfully been implemented at an autocorrelator at FLASH [4]. The x ray FEL pulses will be split by a sharp edge of a silicon mirror coated with Mo B4C multi layers. Both partial beams will then pass variable delay lines. For different wavelengths the angle of incidence onto the multilayer mirrors will be adjusted in order to match the Bragg condition. For a photon energy of h 20 keV a grazing angle of 0.57 has to be set, which results in a footprint of the beam on the mirror of l 120 mm. At this photon energy the reflectance of a Mo B4 C multi layer coating with a multi layer period of d 3.2 nm and N 200 layers amounts to R 0.92. In order to enhance the maximum transmission for photon energies of h 8 keV and below, a Ni B4C multilayer coating can be applied beside the Mo B4C coating for this spectral region. Because of the different incidence angles, the path lengths of the beams will differ as a function of wavelength. Hence, maximum delays between 2.5 ps at h 20 keV and up to 23 ps at h 5 keV will be possibl

    On the characterization of ultra-precise VUV-focusing mirrors by means of slope measuring deflectometry

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    Slope measuring deflectometry allows the non-contact measuring of curves surfaces like ultra-precise elliptical cylinder shaped mirrors in use for the focusing of Synchrotron light. This paper will report on the measurement of synchrotron mirrors designed to guide and focus Synchrotron light in the variable polarization beamline P04 at the PETRA III synchrotron at DESY (Hamburg). These mirrors were optimized by deterministic finishing technology based on topography data provided by slope measuring deflectometry. We will show the results of the mirror inspection and discuss the expected beamline performance by ray-tracing results

    Development of a new generation of optical slope measuring profiler

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    A collaboration, including all DOE synchrotron labs, industrial vendors of x-ray optics, and with active participation of the HBZ-BESSY-II optics group has been established to work together on a new slope measuring profiler -- the optical slope measuring system (OSMS). The slope measurement accuracy of the instrument is expected to be<50 nrad for the current and future metrology of x-ray optics for the next generation of light sources. The goals were to solidify a design that meets the needs of mirror specifications and also be affordable; and to create a common specification for fabrication of a multi-functional translation/scanning (MFTS) system for the OSMS. This was accomplished by two collaborative meetings at the ALS (March 26, 2010) and at the APS (May 6, 2010)

    Biaryl sulfonamides as cisoid azosteres for photopharmacology

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    Biaryl sulfonamides are excellent candidates for the azologization approach that yields photoswitchable drugs more active in their metastable cis state, compared to the stable trans state. Here we present the scope and limitations of this strategy for rational design in photopharmacology

    Examination of macro- and microelements distribution between total extract and fractions for nootropic plant-derived raw material Alfredia cernua

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    The paper dwells on a quantitative determination of macro- and microelements in the ethanol Alfredia cernua extract and its chloroform, ethyl acetate, and butanol fractions. The distribution of macro- and microelements in the extract and fractions was investigated to further study of the interrelation between chemical composition and nootropic activity Alfredia cernua. It is shown that B, Fe, and Sn is mainly accumulated in butanol and Si, P, Al - in chloroform fraction respectively, but most macro- and microelements remain in the ethanol extract
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