Faculty Profiles - 松山　智至

Papers - 松山　智至

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Development of new diagnostics based on LiF detector for pump-probe experiments Reviewed

T. Pikuz, A. Faenov, N. Ozaki, T. Matsuoka, B. Albertazzi, N. J. Hartley, K. Miyanishi, K. Katagiri, S. Matsuyama, K. Yamauchi, H. Habara, Y. Inubushi, T. Togashi, H. Yumoto, H. Ohashi, Y. Tange, T. Yabuuchi, M. Yabashi, A. N. Grum-Grzhimailo, A. Casner, I. Skobelev, S. Makarov, S. Pikuz, G. Rigon, M. Koenig, K. A. Tanaka, T. Ishikawa, R. Kodama

Matter and Radiation at Extremes Vol. 3 ( 4 ) page： 197 - 206 2018.1

Language：English Publishing type：Research paper (scientific journal)

We present new diagnostics for use in optical laser pump - X-ray Free Electron Laser (XFEL) probe experiments to monitor dimensions, intensity profile and focusability of the XFEL beam and to control initial quality and homogeneity of targets to be driven by optical laser pulse. By developing X-ray imaging, based on the use of an LiF crystal detector, we were able to measure the distribution of energy inside a hard X-ray beam with unprecedented high spatial resolution (∼1 μm) and across a field of view larger than some millimetres. This diagnostic can be used in situ, provides a very high dynamic range, has an extremely limited cost, and is relatively easy to be implemented in pump-probe experiments. The proposed methods were successfully applied in pump-probe experiments at the SPring-8 Angstrom Compact free electron LAser (SACLA) XFEL facility and its potential was demonstrated for current and future High Energy Density Science experiments.

DOI： 10.1016/j.mre.2018.01.006

Scopus

超精密X線ミラーが拓く次世代X線集光・結像 Invited

松山智至

2018.1

High-efficiency planarization of GaN by catalyst-referred etching using photo-electrochemical oxidation

KIDA Hideka, TOH Daisetsu, OHNISHI Ryosuke, Matsuyama Tomohisa, Sano Yasuhisa, Yamauchi Kazuto

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2018 page： S1630004 2018

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

In this study, a gallium nitride (GaN) substrate produced was planarized using catalyst-referred etching (CARE). To improve the removal rate, the GaN substrate was processed using CARE-assisted photoelectrochemical (PEC) reaction (PEC CARE); the removal rate was 77 nm/h. However, the shape was embossed because of subsurface scratches introduced during preprocessing. These scratches were removed when the PEC CARE process was conducted under an applied potential of 2.5 V; The removal rate was 800 nm/h. In addition, a smooth surface of surface roughness 0.4 nm rms was obtained. A surface with step-terrace structures on the entire substrate was subsequently obtained when the CARE process was performed using a platinum (Pt) catalyst and deionized water; in this case, the surface roughness was 0.11 nm rms and the removal rate was 5 nm/h.

DOI： 10.1299/jsmemecj.2018.s1630004

In Situ Characterization of XFEL Beam Intensity Distribution and Focusability by High-Resolution LiF Crystal Detector

T. A. Pikuz, A. Ya. Faenov, T. Matsuoka, B. Albertazzi, N. Ozaki, N. Hartely, O. Muray Ricardo Arturo, T. Yabuuchi, H. Habara, S. Matsuyama, K. Yamauchi, Y. Inubushi, T. Togashi, H. Yumoto, Y. Tange, K. Tono, Y. Sato, M. Yabashi, M. Nishikino, T. Kawachi, A. Mitrofanov, S. A. Pikuz, D. Bleiner, A. Grum-Grzhimailo, N. N. Rosanov, N. V. Vysotina, M. Harmand, M. Koenig, K. A. Tanaka, T. Ishikawa, R. Kodama

Springer Proceedings in Physics Vol. 202 page： 109 - 115 2018

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Springer Science and Business Media, LLC

We present here a new diagnostics based on using LiF crystal detectors that are able to perform measurements an intensity distribution of X-rays beams with diameters ranging from some microns up to some centimetres with high spatial resolution (~1 µm). In situ, 3D visualization of SACLA XFEL focused beam profile along propagation, including propagation inside photoluminescence solid materials, is demonstrated. Also, a high spatial resolution control a quality of targets used in optical laser pump—XFEL probe HEDS experiments is proposed.

DOI： 10.1007/978-3-319-73025-7_17

Scopus

High-efficiency planarization of SiC in pure water using a thin film catalyst

Pho Van Bui, Yuta Nakahira, Daisetsu Toh, Satoshi Matsuyama, Yasuhisa Sano, Kazuto Yamauchi

European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 18th International Conference and Exhibition, EUSPEN 2018 page： 433 - 434 2018

Publishing type：Research paper (international conference proceedings)

A novel abrasive-free method called catalyst-referred etching (CARE) has been developed in our group. In this method, a platinum film as a catalyst is deposited on an elastic pad that is rotated in contact with a wafer surface in water. After CARE planarization, SiC surfaces are atomically smooth with a root-mean-square (RMS) roughness of less than 0.1 nm over a whole wafer. Using only pure water as an etchant, CARE is a promising planarization method and potentially applicable to planarization of many semiconductor surfaces, including GaN and oxides surfaces. However, the removal rate (RR) of SiC via CARE using a Pt catalyst is quite low, limiting its practical application. Our recent research on the removal mechanism using density functional theory (DFT) calculations indicated that the etching proceeded via a dissociative adsorption of water molecules onto the Si-C bonds at the topmost Si surface, catalyzed by a Pt catalyst. We expect that the RR can be improved by using the higher reactivity catalyst. Therefore, we experimentally investigate the dependence of RR on various catalyst materials. The results indicate that SiC can be planarized with a high RR using 3d transition metal catalysts. Using DFT calculations, we clarify that a high catalytic reactivity of a 3d transition metal is attributed to the higher chemical binding energy with OH, compared to that of Pt. This high chemical bond promotes water dissociation and stabilizes metastable states by forming chemical bonds at the catalyst-SiC interface, leading to lowering its activation barrier and an enhancement of the etching reaction.

Scopus

Development of high efficiency polishing method using pure water and Ni catalyst

Daisetsu Toh, Pho Van Bui, Nakahira Yuta, Hideka Kida, Takahisa Ohgushi, Satoshi Matsuyama, Yasuhisa Sano, Kazuto Yamauchi

European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 18th International Conference and Exhibition, EUSPEN 2018 page： 435 - 436 2018

Publishing type：Research paper (international conference proceedings)

We have developed "Catalyst Referred Etching" (CARE) using pure water as an etchant and Pt as a catalyst as a new polishing method. Using CARE, many functional materials, such as silicon carbide (SiC), gallium nitride (GaN), and metal oxides, can be planar-ized to atomically well-ordered surfaces with a root-mean-square (RMS) roughness of less than 0.1 nm over a whole wafer. The planarized surface has a step-and-terrace structure, indicating that CARE is step-flow etching type. Thus, the material removal rate (MRR) of CARE using a Pt catalyst, especially for crystalline materials, is quite low, approximately 20 nm/h for SiC. Our recent study shows that the catalytic reactivity of a Ni for CARE is higher than that of a Pt. Additionally, compared to Pt, Ni is cost-effective and abundant, indicating that Ni is a promising catalyst for CARE. However, the MRR using a Ni catalyst usually decreases with the processing time due to catalytic deactivation by oxidation of the Ni surface. Therefore, we use electrochemical deposition method to control Ni surface condition and to keep its surface catalytivally active. First, before CARE processing, the Ni is deposited on a polishing pad by setting its potential to be lower than that of the etchant. The deposited Ni layer works as an active catalyst. Second, after CARE processing, the residual Ni is dissolved into the etchant by changing its potential to be higher than that of the etchant. By alternative repeating these steps, reactive Ni on the polishing pad is continually prepared. Accordingly, the removal rate is stable with processing time. The study reveals that CARE with the potential control method is potential for high-efficiency polishing of functional materials.

Scopus

Wavefront sensing for nano-focusing characterization

S. Matsuyama

9th Hard X-ray FEL Collaboration Meeting (5-way meeting 2017) 2017.12

Ellipsoidal mirror for two-dimensional 100-nm focusing in hard X-ray region Reviewed

H. Yumoto, T. Koyama, S. Matsuyama, Y. Kohmura, K. Yamauchi, T. Ishikawa, H. Ohashi

Scientific Reports Vol. 7 ( 1 ) page： 16408 2017.11

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

Cutting-edge hard X-ray microscopy strongly depends on sophisticated focusing optics and ultrabright X-ray sources at synchrotron-radiation and X-ray free-electron laser (XFEL) facilities. These facilities typically provide two-dimensional nanofocusing X-ray beams by combining one-dimensional focusing mirrors. However, single-reflecting two-dimensional focusing mirrors with an ellipsoidal surface, which are well-known to possess high efficiency, have limited microfocusing applications. In this paper, we present an ultrahigh-precision ellipsoidal mirror for two-dimensional X-ray nanofocusing by overcoming the difficulties faced in the manufacturing process of its aspherical surface, including the surface-processing methods and surface metrology. The developed mirror has nanoscale accuracy, and it achieves focus size of 85 nm x 125 nm (full width at half maximum) using 7-keV X-rays. Two-dimensional focus was demonstrated in the same focal plane by resolving 50-nm test structures by scanning X-ray microscopy using a focusing beam. These achievements represent an important first step toward realizing two-dimensional aspherical mirrors with complex designs, in addition to ultralow loss and unprecedented small focusing property for extensive optical applications in synchrotron-radiation and XFEL facilities as well as in other scientific fields that require ultraprecision optical surfaces.

DOI： 10.1038/s41598-017-16468-1

Web of Science

PubMed

全反射ミラーを用いた色収差のない結像光学系の開発 Invited

松山智至

2017.11

衝撃圧縮された多結晶コランダムの時分割XFELその場観察

丹下慶範, 尾崎典雅, 瀬戸雄介, 佐藤友子, 奥地拓生, 松岡健之, 高橋謙次郎, 宮西宏併, ALBERTAZZI Bruno・HARTLEY Nicholas, 梅田悠平, 西川豊人, 松山智至, 山内和人, 関根利守, 田中和夫, 兒玉了祐, 籔内俊毅, 矢橋牧名

高圧討論会講演要旨集 Vol. 58th 2017.11

Fabrication of X-ray imaging mirror for an achromatic and high-resolution full-field X-ray microscope

J. Yamada, S. Matsuyama, S. Yasuda, Y. Sano, K. Yamauchi

2017.10

Development of crystal-based split-and-delay optics with wavefront splitting at SACLA

T. Hirano, T. Osaka, Y. Sano, Y. Inubushi, T. Togashi, I. Inoue, S. Matsuyama, K. Tono, K. Yamauchi, M. Yabashi

SPIE Optics+Photonics2017 page： 187 - 187 2017.8

高分解能かつ色収差のないX線顕微鏡の開発 Invited

松山智至

日本学術振興会，結晶加工と評価技術第145委員会，第154回研究会 2017.8

高分解能かつ色収差のない X 線顕微鏡の開発 Invited

松山智至

精密工学会学術講演会講演論文集 Vol. 2017 page： 957 - 958 2017.8

Language：Japanese Publisher：公益社団法人精密工学会

高精度なX線全反射ミラーを4枚用いて，高分解能かつ色収差のない結像型X線顕微鏡を開発した．本顕微鏡の実用性を確かめるために，蛍光X線イメージング，暗視野イメージング，位相イメージングを実施した．暗視野イメージングでは，後焦点位置にナイフエッジを挿入した．位相イメージングでは，位相回折格子を用いたタルボ効果を利用した．ポリスチレン球や金属微粒子，テストチャートの観察について詳細に報告する．

DOI： 10.11522/pscjspe.2017S.0_957

Full-field X-ray fluorescence imaging based on total-reflection imaging mirrors

S. Matsuyama, S. Yasuda, J. Yamada, Y. Kohmura, M. Yabashi, T. Ishikawa, K. Yamauchi

The 24th Congress of the International Comission for Optics, X-ray and High-energy Optics 2017.8

Development of precision Wolter mirrors for solar x-ray observations

Taro Sakao, Satoshi Matsuyama, Takumi Goto, Jumpei Yamada, Shuhei Yasuda, Kazuto Yamauchi, Yoshiki Kohmura, Ayumi Kime, Akira Miyake, Tadakazu Maezawa, Hirokazu Hashizume, Yoshinori Suematsu, Noriyuki Narukage, Shin-nosuke Ishikawa

Proceedings of SPIE Vol. 10386 page： 103860E-1 - 103860E-11 2017.8

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

High resolution imagery of the Sun's X-ray corona provides an essential clue in understanding dynamics and heating processes of plasma particles there. However, X-ray imagery of the Sun with sub-arcsecond resolution has so far never been conducted due to severe technical difficulty in fabricating precision Wolter mirrors. For future X-ray observations of the solar corona, we are attempting to realize precision Wolter mirrors with sub-arcsecond resolution by adopting advanced surface polish and metrology methods to sector mirrors which consist of a portion of an entire annulus, by direct polishing onto the mirror substrate.
Based on the knowledge obtained through fabrication of the first (in 2013) and second (in 2014) engineering Wolter mirrors and subsequent evaluations on their X-ray focusing performance, the third engineering mirror was made in 2015-2016. The primary target of improvement over the second mirror was to suppress figure error amplitude especially for spatial frequencies around 1 mm(-1) and to suppress the large astigmatism that was present in the second mirror, by introducing improved deterministic polish and smoothing on the precision mirror surfaces (32.5 mm x 10 mm in area for both parabola and hyperbola segments), as well as by careful characterization of the systematic error in the figure measurement system for the precision polish. Measurements on the focusing performance of thus-fabricated third Wolter mirror at SPring-8 synchrotron facility with 8 keV X-rays demonstrated that the mirror attained sub-arcsecond focusing performance with its HPD (half-power diameter) size reaching as small as similar to 0.2 arcsec for meridional focusing while similar to 0.1 arcsec for sagittal focusing. The meridional focusing achieved nearly diffraction limited performance (similar to 0.12 arcsec FWHM for the PSF core). We also confirmed that the large astigmatism noted in the second mirror was correctly removed in the third mirror with the correction of the above-mentioned systematic error.

DOI： 10.1117/12.2273507

Web of Science

Development of Precise Wavefront Measurement Method for X-Ray Free Electron Laser Focusing System

T. Inoue, S. Matsuyama, S. Kawai, H. Yumoto, Y. Inubushi, T. Osaka, T. Koyama, K. Tono, H. Ohashi, M. Yabashi, T. Ishikawa, K. Yamauchi

The 24th Congress of the International Comission for Optics, X-ray and High-energy Optics 2017.8

Development of measurement system for ellipsoidal mirrors

H. Nakamori, Y. Ichii, H. Okada, A. Ueda, T. Tsumura, S. Matsuyama, K. Yamauchi

SPIE Optics+Photonics2017 page： 185 - 185 2017.8

Development of measurement system for ellipsoidal mirrors Reviewed

H. Nakamori, Y. Ichii, H. Okada, A. Ueda, T. Tsumura, S. Matsuyama, K. Yamauchi

2017.8

Development of hybrid adaptive x-ray focusing system based on piezoelectric bimorph mirror and mirror bender Reviewed

T. Goto, S. Matsuyama, H. Hayashi, J. Sonoyama, K. Akiyama, H. Nakamori, Y. Sano, K. Yamauchi

SPIE Optics+Photonics2017 page： 187 - 187 2017.8

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Papers - 松山 智至

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Papers - 松山　智至