X-Ray Single-Grating Interferometry for Wavefront Measurement and Correction of Hard X-Ray Nanofocusing Mirrors

X-ray single-grating interferometry was applied to conduct accurate wavefront corrections for hard X-ray nanofocusing mirrors. Systematic errors in the interferometer, originating from a grating, a detector, and alignment errors of the components, were carefully examined. Based on the measured wavefront errors, the mirror shapes were directly corrected using a differential deposition technique. The corrected X-ray focusing mirrors with a numerical aperture of 0.01 attained two-dimensionally diffraction-limited performance. The results of the correction indicate that the uncertainty of the wavefront measurement was less than λ/72 in root-mean-square value.Yamada, J.; Inoue, T.; Nakamura, N.; Kameshima, T.; Yamauchi, K.; Matsuyama, S.; Yabashi, M. X-Ray Single-Grating Interferometry for Wavefront Measurement and Correction of Hard X-Ray Nanofocusing Mirrors. Sensors 2020, 20, 7356. https://doi.org/10.3390/s20247356

Development of concave-convex imaging mirror system for a compact and achromatic full-field x-ray microscope

Jumpei Yamada, Satoshi Matsuyama, Shuhei Yasuda, Yasuhisa Sano, Yoshiki Kohmura, Makina Yabashi, Tetsuya Ishikawa, and Kazuto Yamauchi "Development of concave-convex imaging mirror system for a compact and achromatic full-field x-ray microscope", Proc. SPIE 10386, Advances in X-Ray/EUV Optics and Components XII, 103860C (6 September 2017); https://doi.org/10.1117/12.2272904

Single-Shot Spectrometry for X-Ray Free-Electron Lasers

An experimental scheme to realize single-shot spectrometry for the diagnostics of x-ray free-electron lasers (XFELs) is presented. The combination of an ultraprecisely figured mirror and a perfect crystal form a simple, high-precision spectrometer that can cover an energy range from a few eV to a hundred eV with high resolution. The application of the spectrometer to determine XFEL pulse widths was investigated theoretically and experimentally. It has been shown that the present system can determine pulse widths from sub-fs to ps in a single shot even for spontaneous radiation. The system can be easily extended to even shorter pulses.Makina Yabashi, Jerome B. Hastings, Max S. Zolotorev, Hidekazu Mimura, Hirokatsu Yumoto, Satoshi Matsuyama, Kazuto Yamauchi, and Tetsuya Ishikawa. Phys. Rev. Lett. 97(8), 084802 (2006)

Development of speckle-free channel-cut crystal optics using plasma chemical vaporization machining for coherent x-ray applications

We have developed a method of fabricating speckle-free channel-cut crystal optics with plasma chemical vaporization machining, an etching method using atmospheric-pressure plasma, for coherent X-ray applications. We investigated the etching characteristics to silicon crystals and achieved a small surface roughness of less than 1 nm rms at a removal depth of >10 μm, which satisfies the requirements for eliminating subsurface damage while suppressing diffuse scattering from rough surfaces. We applied this method for fabricating channel-cut Si(220) crystals for a hard X-ray split-and-delay optical system and confirmed that the crystals provided speckle-free reflection profiles under coherent X-ray illumination.Takashi Hirano, Taito Osaka, Yasuhisa Sano, Yuichi Inubushi, Satoshi Matsuyama, Kensuke Tono, Tetsuya Ishikawa, Makina Yabashi, and Kazuto Yamauchi, "Development of speckle-free channel-cut crystal optics using plasma chemical vaporization machining for coherent x-ray applications", Review of Scientific Instruments 87, 063118 (2016) https://doi.org/10.1063/1.4954731