Takahisa Koyama
University of Hyogo
74 Papers
177 Citations
Takahisa Koyama is an academic researcher from University of Hyogo. The author has contributed to research in topics: Laser & Free-electron laser. The author has an hindex of 15, co-authored 54 publications.
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Papers
Generation of an X-ray nanobeam of a free-electron laser using reflective optics with speckle interferometry.
Takato Inoue,Satoshi Matsuyama,Jumpei Yamada,Nami Nakamura,Taito Osaka,Ichiro Inoue,Yuichi Inubushi,Kensuke Tono,Hirokatsu Yumoto,Takahisa Koyama,Haruhiko Ohashi,Makina Yabashi,Tetsuya Ishikawa,Kazuto Yamauchi +13 more
TL;DR: X-ray nanobeams of a free-electron laser were generated using reflective focusing optics combined with speckle interferometry to enable the production of ultrahigh-intensity X-ray pulses.
BL09XU: an advanced hard X-ray photoelectron spectroscopy beamline of SPring-8
Akira Yasui,Yasumasa Takagi,Taito Osaka,Yasunori Senba,T. Yamazaki,Takahisa Koyama,Hirokatsu Yumoto,Haruhiko Ohashi,Koji Motomura,K. Nakajima,Michihiro Sugahara,Naomi Kawamura,Kenji Tamasaku,Yusuke Tamenori,Makina Yabashi +14 more
TL;DR: BL09XU is a newly upgraded hard X-ray photoelectron spectroscopy beamline at SPring-8 with improved optical instruments.
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A Precision Grazing-incidence Angle Error Measurement of a Hard X-ray Condenser Mirror Using Single-grating Interferometry
Ryosuke Fukui,Jangwoo Kim,Satoshi Matsuyama,Hirokatsu Yumoto,Yuichi Inubushi,Kensuke Tono,Takahisa Koyama,Takashi Kimura,Hidekazu Mimura,Haruhiko Ohashi,Makina Yabashi,Tetsuya Ishikawa,Kazuto Yamauchi +12 more
TL;DR: In this article, the spatial resolution of scanning microscopy directly depends on the focal spot size, which is significantly degraded by errors in the mirror shape and misalignment of the mirror.
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Damage study of optical substrates using 1-μm-focusing beam of hard X-ray free-electron laser
Takahisa Koyama,Hirokatsu Yumoto,Yasunori Senba,Kensuke Tono,T. Sato,Tadashi Togashi,Yuichi Inubushi,Jangwoo Kim,Takashi Kimura,Satoshi Matsuyama,Hidekazu Mimura,Makina Yabashi,Kazuto Yamauchi,Haruhiko Ohashi,T. Ishikawa +14 more
- 25 Oct 2013
TL;DR: In this article, a focusing XFEL beam with a beam size of approximately 1?m at a photon energy of 10 keV was used to evaluate the ablation threshold of silicon and synthetic fused silica, which are widely used as optical substrates such as those in X-ray mirrors.
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Overview of optics, photon diagnostics and experimental instruments at SACLA: development, operation and scientific applications
Kensuke Tono,Tadashi Togashi,Yuichi Inubushi,Tetsuo Katayama,Shigeki Owada,Toshinori Yabuuchi,Akira Kon,Ichiro Inoue,Taito Osaka,Hirokatsu Yumoto,Takahisa Koyama,Haruhiko Ohashi,Makina Yabashi +12 more
TL;DR: In this paper, the beamline optical and diagnostics systems have been upgraded to further accelerate the scientific applications of X-ray free-electron lasers (XFELs) and end-station instruments have also been developed to provide user-friendly experimental platforms which allow efficient data collection.
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