IMPROVEMENT OF BEAM DIVERGENCE IN PSEUDOPARABOLOIDAL BENDING OF AN X-RAY MIRROR

The surface of a flat-plate quartz mirror has been investigated by bending it into a pseudoparaboloid with the mirror bender in BL-3A. The evaluation of the beam collimation and actual mirror curvature have been made by x-ray diffraction using the (+,-,-) arrangement of Si(111) crystals. The FWHM in (+,-,-) rocking curves of a whole beam was reduced from 42.7 to 14.1 arcsec with the collimating mirror. The distances deviating from the ideal paraboloid were found to be very small, i.e., less than 0.6 and 3.5 μm in ±200 and ±400 mm in the mirror length, respectively. The efficiency of the mirror was also estimated from the CeO2 diffraction patterns which were slightly but significantly improved in FWHM and peak intensity with the collimation. © 1995 American Institute of Physics.