Generation of an X-ray microbeam for spectromicroscopy at SPring-8 BL39XU

A pair of elliptical mirrors (KB mirror) was designed and fabricated to rea lize an energy tunable x-ray microbeam for spectro-microscopy at SPring-8 B L39XU. As is commonly recognized, the obtainable beam size with the aspheri cal total reflection mirrors is strongly affected with the slope error of t he mirror. Considering that the extremely high brilliance of the undulator radiation from the SPring-8, the small mirror size and the small mirror-to- focus distance were employed to minimize effects of the slope error. Prelim inary evaluation of the KB mirror was carried out using 10 keV monochromati zed undulator radiation. Alignment of the mirror was assisted by the beam m onitor system composed of a scintillator and a CCD, and the beam size less than 5 mum can be easily achieved even when the source was fully used. The beam size obtained with this experiment was 2 x 4 mum(2) with the photon fl ux of 1 x 10(10) photons/s. Smaller beam size may be expected with the use of intermediate slits. Characterization of trace elements with the spatial resolution will be carried out by using x-ray fluorescence (XRF) analysis a nd x-ray absorption fine structure (XAFS) measurements with XRF yield metho d.