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22 November 1996 X-ray focusing using elliptically bent multilayers
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We present the x-ray performance on an ESRF synchrotron beamline of a focusing device based on the dynamical bending of a flat silicon plate coated with a 2.5 m d-spacing W/Si multilayer. The mirror was shaped by trial and error to a cylindrical ellipse using an optical profilometer. In a first experiment the device was bent to a 71-m radius to account for the demagnification factor and the energy of operation. With a monochromatic incident beam set at 9 keV a vertical spot size of 4.5 micrometers was obtained at 41 m from the source and 1 m from the multilayer, which agreed closely with theoretical expectations. Such good agreement was due to small residual slope error with respect to the ellipse: around 2 (mu) rad over a 150-mm length for radii greater than 50 m. Moreover, as the divergence of the incident beam was larger than the rocking curve width, less than 25% of the mirror could contribute, reducing the distortion to an even lower figure. With the same geometrical parameters the device exposed to the white beam (monochromator removed) lead to a vertical spot size of about 7 micrometers . Here the whole mirror surface cold reflect, which caused more distortion to the incoming beam but also gave rise to a much higher intensity. The gain in flux obtained with a gradient of d-spacing along the mirror surface is discussed. Finally, results with a Kirpatrick-Baez arrangement let expect in the near future a flux gain greater than 104 with a 10 micrometers by 10 micrometers focal spot.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Eric Ziegler, Olivier Hignette, Manohar Lingham, and Alexei Souvorov "X-ray focusing using elliptically bent multilayers", Proc. SPIE 2856, Optics for High-Brightness Synchrotron Radiation Beamlines II, (22 November 1996);


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