Hard X-ray Focusing less than 50nm for Nanoscopy/spectroscopy.

X-ray focusing using a Kirkpatrick-Baez (KB) setup with two total reflection mirrors is a promising method, allowing highly efficient and energy-tunable focusing. Fabricated mirrors having a figure accuracy of 1 nm peak-to-valley height gave ideal diffraction-limited focusing of hard X-rays. The focal size, defined as the full width at half maximum of the intensity profile, was 36 nm × 48 nm at an X-ray energy of 15 keV. Fluorescence X-ray microscopy with KB mirrors was also developed, targeting cell biological applications. The distribution of various elements in a single cell was successfully observed with high resolution. The developed microscopy is already used for various applications in the medical field. Our next main project is the realization of sub-10-nm-level hard X-ray focusing. At-wavelength metrology is being developed, in which a phase-retrieval simulator is coded for the determination of phase errors on mirror surfaces from only the intensity profiles of a focused beam. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]