2024/05/23 更新

写真b

イシカワ シンノスケ
石川 真之介
ISHIKAWA Shin-Nosuke
*大学が定期的に情報更新している項目(その他は、researchmapの登録情報を転載)
所属*
人工知能科学研究科 人工知能科学専攻 博士課程前期課程
人工知能科学研究科 人工知能科学専攻 博士課程後期課程
職名*
特任准教授
研究テーマ*
  • 民間企業における課題解決を含めた社会のさまざまな場面でのAI活用の研究とともに、人がAIと協調していくための技術として、特にAIの説明性、解釈性に関する研究を行っている。テキスト生成モデルに対しては、結果と推論の妥当性を向上させる論理思考能力や、論理思考を超えた感性をテーマとして、評価方法や能力向上の方法について検討している。生成AIを、あいまいな入力と具体的・個別的な出力を結びつける仕組みであると捉え、人間に負荷をかけずに柔軟にタスクに対応できるようにすることを目指している。【略歴】2011年、東京大学大学院理学系研究科修了。理学博士。カリフォルニア大学バークレー校、JAXA 他での研究員を経て、2019年より株式会社豆蔵に入社。デジタル戦略支援事業部所属、AI-techチームリーダー。

  • 学内職務経歴*
    • 2022年4月 - 現在 
      人工知能科学研究科   人工知能科学専攻 博士課程前期課程   特任准教授
    • 2022年4月 - 現在 
      人工知能科学研究科   人工知能科学専攻 博士課程後期課程   特任准教授
     

    論文

    • Example-based explainable AI and its application for remote sensing image classification

      Shin-nosuke Ishikawa, Masato Todo, Masato Taki, Yasunobu Uchiyama, Kazunari Matsunaga, Peihsuan Lin, Taiki Ogihara, Masao Yasui

      International Journal of Applied Earth Observation and Geoinformation   2023年4月

      詳細を見る

      掲載種別:研究論文(学術雑誌)  

      DOI: 10.1016/j.jag.2023.103215

      researchmap

    • The faintest solar coronal hard X-rays observed with FOXSI

      Juan Camilo Buitrago-Casas, Lindsay Glesener, Steven Christe, Sam Krucker, Juliana Vievering, P. S. Athiray, Sophie Musset, Lance Davis, Sasha Courtade, Gregory Dalton, Paul Turin, Zoe Turin, Brian Ramsey, Stephen Bongiorno, Daniel Ryan, Tadayuki Takahashi, Kento Furukawa, Shin Watanabe, Noriyuki Narukage, Shin-nosuke Ishikawa, Ikuyuki Mitsuishi, Kouichi Hagino, Van Shourt, Jessie Duncan, Yixian Zhang, Stuart D. Bale

      ASTRONOMY & ASTROPHYSICS665   2022年9月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:EDP SCIENCES S A  

      Context. Solar nanoflares are small impulsive events releasing magnetic energy in the corona. If nanoflares follow the same physics as their larger counterparts, they should emit hard X-rays (HXRs) but with a rather faint intensity. A copious and continuous presence of nanoflares would result in a sustained HXR emission. These nanoflares could deliver enormous amounts of energy into the solar corona, possibly accounting for its high temperatures. To date, there has not been any direct observation of such persistent HXRs from the quiescent Sun. However, the quiet-Sun HXR emission was constrained in 2010 using almost 12 days of quiescent solar off-pointing observations by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). These observations set 2 sigma upper limits at 3.4 x 10(-2) photons s(-1) cm(-2) keV(-1) and 9.5 x 10(-4) photons s(-1) cm(-2) keV(-1) for the 3-6 keV and 6-12 keV energy ranges, respectively. Aims. Observing faint HXR emission is challenging because it demands high sensitivity and dynamic range instruments. The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment excels in these two attributes when compared with RHESSI. FOXSI completed its second and third successful flights (FOXSI-2 and -3) on December 11, 2014, and September 7, 2018, respectively. This paper aims to constrain the quiet-Sun emission in the 5-10 keV energy range using FOXSI-2 and -3 observations. Methods. To fully characterize the sensitivity of FOXSI, we assessed ghost ray backgrounds generated by sources outside of the field of view via a ray-tracing algorithm. We used a Bayesian approach to provide upper thresholds of quiet-Sun HXR emission and probability distributions for the expected flux when a quiet-Sun HXR source is assumed to exist. Results. We found a FOXSI-2 upper limit of 4.5 x 10(-2) photons s(-1) cm(-2) keV(-1) with a 2 sigma confidence level in the 5-10 keV energy range. This limit is the first-ever quiet-Sun upper threshold in HXR reported using similar to 1 min observations during a period of high solar activity. RHESSI was unable to measure the quiet-Sun emission during active times due to its limited dynamic range. During the FOXSI-3 flight, the Sun exhibited a fairly quiet configuration, displaying only one aged nonflaring active region. Using the entire similar to 6.5 min of FOXSI-3 data, we report a 2 sigma upper limit of similar to 10(-4) photons s(-1) cm(-2) keV(-1) for the 5-10 keV energy range. Conclusions. The FOXSI-3 upper limits on quiet-Sun emission are similar to that previously reported, but FOXSI-3 achieved these results with only 5 min of observations or about 1/2600 less time than RHESSI. A possible future spacecraft using hard X-ray focusing optics like those in the FOXSI concept would allow enough observation time to constrain the current HXR quiet-Sun limits further, or perhaps even make direct detections. This is the first report of quiet-Sun HXR limits from FOXSI and the first science paper using FOXSI-3 observations.

      DOI: 10.1051/0004-6361/202243272

      researchmap

    • FOXSI-2 Solar Microflares. II. Hard X-ray Imaging Spectroscopy and Flare Energetics

      Juliana T. Vievering, Lindsay Glesener, P. S. Athiray, Juan Camilo Buitrago-Casas, Sophie Musset, Daniel F. Ryan, Shin-nosuke Ishikawa, Jessie Duncan, Steven Christe, Säm Krucker

      The Astrophysical Journal913 ( 1 ) 15 - 15   2021年5月1日

      詳細を見る

      掲載種別:研究論文(学術雑誌)   出版者・発行元:American Astronomical Society  

      DOI: 10.3847/1538-4357/abf145

      researchmap

    • Automatic Detection of Occulted Hard X-Ray Flares Using Deep-Learning Methods

      Shin-nosuke Ishikawa, Hideaki Matsumura, Yasunobu Uchiyama, Lindsay Glesener

      Solar Physics296 ( 2 )   2021年2月

      詳細を見る

      掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media {LLC}  

      DOI: 10.1007/s11207-021-01780-x

      researchmap

    • FOXSI-2 Solar Microflares. I. Multi-instrument Differential Emission Measure Analysis and Thermal Energies

      P. S. Athiray, Juliana Vievering, Lindsay Glesener, Shin-nosuke Ishikawa, Noriyuki Narukage, Juan Camilo Buitrago-Casas, Sophie Musset, Andrew Inglis, Steven Christe, Säm Krucker, Daniel Ryan

      The Astrophysical Journal891 ( 1 ) 78 - 78   2020年3月1日

      詳細を見る

      掲載種別:研究論文(学術雑誌)   出版者・発行元:American Astronomical Society  

      DOI: 10.3847/1538-4357/ab7200

      researchmap

    • Hot Plasma in a Quiescent Solar Active Region as Measured by RHESSI, XRT, and AIA

      Shin-nosuke Ishikawa, Säm Krucker

      The Astrophysical Journal876 ( 2 ) 111 - 111   2019年5月10日

      詳細を見る

      掲載種別:研究論文(学術雑誌)   出版者・発行元:American Astronomical Society  

      DOI: 10.3847/1538-4357/ab13a1

      researchmap

    • Development of 60 μm pitch CdTe double-sided strip detectors for the FOXSI-3 sounding rocket experiment 査読有り

      Kento Furukawa, Juan Camilo Buitrago-Casas, Juliana Vievering, Kouichi Hagino, Lindsay Glesener, P. S. Athiray, Säm Krucker, Shin Watanabe, Shin'ichiro Takeda, Shin'nosuke Ishikawa, Sophie Musset, Steven Christe, Tadayuki Takahashi

      Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment924   321 - 326   2019年4月

      詳細を見る

      掲載種別:研究論文(学術雑誌)  

      © 2018 Elsevier B.V. FOXSI-3 (Focusing Optics X-ray Solar Imager) is an international sounding rocket experiment to observe hard X-rays from the Sun. The previous two flights successfully demonstrated the efficacy of the concept of direct solar imaging in hard X-ray band. For the third launch scheduled in the summer of 2018, we have fabricated a prototype of the CdTe Double-sided Strip Detector. To evaluate the basic performance, laboratory tests were conducted. Energy resolution (FWHM) of 0.8 keV at 13.9 keV and 1.3 keV at 59.5 keV are confirmed. Since the optic angular resolution is finer than the strip pitch of the detector at the focal plane, sub-strip position determination is important to make full use of the high precision of the optic. To test the possibility of sub-strip resolution, we developed a new method of investigating the detector strips with a fine multi-pinhole collimator. The results of the analysis were highly favorable and we confirmed the sub-strip resolution by making sub-strip images of multi-pinholes and flat-irradiation. The spectral uniformity over the detector is also confirmed using the sub-strip image of flat-irradiation.

      DOI: 10.1016/j.nima.2018.07.011

      Scopus

      researchmap

    • Ghost ray reduction and early results from the third FOXSI sounding rocket flight 査読有り

      Sophie Musset, Juan Camilo Buitrago-Casas, Lindsay Glesener, Stephen Bongiorno, Sasha Courtade, P. S. Athiraya, Juliana Vievering, Shin-Nosuke Ishikawa, Noriyuki Narukage, Kento Furukawa, Daniel Ryan, Gregory Dalton, Zoe Turin, Lance Davisa, Tadayuki Takahashi, Shin Watanabe, Ikuyuki Mitsuishi, Kouichi Hagino, Tomoko Kawate, Paul Turin, Steven Christe, Brian Ramsey, Sam Krucker

      UV, X-RAY, AND GAMMA-RAY SPACE INSTRUMENTATION FOR ASTRONOMY XXI11118   2019年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

      The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment demonstrates the technique of focusing hard X-ray (HXR) optics for the study of fundamental questions about the high-energy Sun. Solar HXRs provide one of the most direct diagnostics of accelerated electrons and the impulsive heating of the solar corona. Previous solar missions have been limited in sensitivity and dynamic range by the use of indirect imaging, but technological advances now make direct focusing accessible in the HXR regime, and the FOXSI rocket experiment optimizes HXR focusing telescopes for the unique scientific requirements of the Sun. FOXSI has completed three successful flights between 2012 and 2018. This paper gives a brief overview of the experiment, focusing on the third flight of the instrument on 2018 Sept. 7. We present the telescope upgrades highlighting our work to understand and reduce the effects of singly reflected X-rays and show early science results obtained during FOXSI's third flight.

      DOI: 10.1117/12.2530029

      researchmap

    • Hard X-Ray Constraints on Small-scale Coronal Heating Events

      Andrew J. Marsh, David M. Smith, Lindsay Glesener, James A. Klimchuk, Stephen J. Bradshaw, Juliana Vievering, Iain G. Hannah, Steven Christe, Shin-nosuke Ishikawa, Säm Krucker

      The Astrophysical Journal864 ( 1 ) 5 - 5   2018年9月1日

      詳細を見る

      掲載種別:研究論文(学術雑誌)   出版者・発行元:American Astronomical Society  

      DOI: 10.3847/1538-4357/aad380

      researchmap

    • Detection of nanoflare-heated plasma in the solar corona by the FOXSI-2 sounding rocket

      Shin-nosuke Ishikawa, Lindsay Glesener, Säm Krucker, Steven Christe, Juan Camilo Buitrago-Casas, Noriyuki Narukage, Juliana Vievering

      Nature Astronomy   2017年10月9日

      詳細を見る

      掲載種別:研究論文(学術雑誌)  

      DOI: 10.1038/s41550-017-0269-z

      researchmap

    • CLASP/SJ Observations of Rapid Time Variations in the Lyα Emission in a Solar Active Region

      Shin-nosuke Ishikawa, Masahito Kubo, Yukio Katsukawa, Ryouhei Kano, Noriyuki Narukage, Ryohko Ishikawa, Takamasa Bando, Amy Winebarger, Ken Kobayashi, Javier Trujillo Bueno, Frédéric Auchère

      The Astrophysical Journal846 ( 2 ) 127 - 127   2017年9月10日

      詳細を見る

      掲載種別:研究論文(学術雑誌)   出版者・発行元:American Astronomical Society  

      DOI: 10.3847/1538-4357/aa862e

      researchmap

    • Constraining hot plasma in a non-flaring solar active region with FOXSI hard X-ray observations 査読有り

      Shin-Nosuke Ishikawa, Lindsay Glesener, Steven Christe, Kazunori Ishibashi, David H. Brooks, David R. Williams, Masumi Shimojo, Nobuharu Sako, Saem Krucker

      PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN66   2014年12月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

      We present new constraints on the high-temperature emission measure of a non-flaring solar active region using observations from the recently flown Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload. FOXSI has performed the first focused hard X-ray (HXR) observation of the Sun in its first successful flight on 2012 November 2. Focusing optics, combined with small strip detectors, enable high-sensitivity observations with respect to previous indirect imagers. This capability, along with the sensitivity of the HXR regime to high-temperature emission, offers the potential to better characterize high-temperature plasma in the corona as predicted by nanoflare heating models. We present a joint analysis of the differential emission measure (DEM) of active region 11602 using coordinated observations by FOXSI, Hinode/XRT, and Hinode/EIS. The Hinode-derived DEM predicts significant emission measure between 1MK and 3MK, with a peak in the DEM predicted at 2.0-2.5MK. The combined XRT and EIS DEM also shows emission from a smaller population of plasma above 8MK. This is contradicted by FOXSI observations that significantly constrain emission above 8 MK. This suggests that the Hinode DEM analysis has larger uncertainties at higher temperatures and that > 8MK plasma above an emission measure of 3 x 10(44) cm(-3) is excluded in this active region.

      DOI: 10.1093/pasj/psu090

      researchmap

    • FIRST IMAGES FROM THE FOCUSING OPTICS X-RAY SOLAR IMAGER 査読有り

      Saem Krucker, Steven Christe, Lindsay Glesener, Shin-Nosuke Ishikawa, Brian Ramsey, Tadayuki Takahashi, Shin Watanabe, Shinya Saito, Mikhail Gubarev, Kiranmayee Kilaru, Hiroyasu Tajima, Takaaki Tanaka, Paul Turin, Stephen McBride, David Glaser, Jose Fermin, Stephen White, Robert Lin

      ASTROPHYSICAL JOURNAL LETTERS793 ( 2 )   2014年10月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

      The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload flew for the first time on 2012 November 2, producing the first focused images of the Sun above 5 keV. To enable hard X-ray (HXR) imaging spectroscopy via direct focusing, FOXSI makes use of grazing-incidence replicated optics combined with fine-pitch solid-state detectors. On its first flight, FOXSI observed several targets that included active regions, the quiet Sun, and a GOES-class B2.7 microflare. This Letter provides an introduction to the FOXSI instrument and presents its first solar image. These data demonstrate the superiority in sensitivity and dynamic range that is achievable with a direct HXR imager with respect to previous, indirect imaging methods, and illustrate the technological readiness for a spaceborne mission to observe HXRs from solar flares via direct focusing optics.

      DOI: 10.1088/2041-8205/793/2/L32

      researchmap

    • The focusing optics X-ray solar imager (FOXSI): Instrument and first flight

      Säm Krucker, Steven Christe, Lindsay Glesener, Shinnosuke Ishikawa, Brian Ramsey, Mikhail Gubarev, Shinya Saito, Tadayuki Takahashi, Shin Watanabe, Hiroyasu Tajima, Takaaki Tanaka, Paul Turin, David Glaser, Jose Fermin, Robert P. Lin

      Proceedings of SPIE - The International Society for Optical Engineering8862   2013年

      詳細を見る

      掲載種別:研究論文(国際会議プロシーディングス)  

      Solar flares accelerate particles up to high energies (MeV and GeV scales for electrons and ions, respectively) through efficient acceleration processes that are not currently understood. Hard X-rays (HXRs) are the most direct diagnostic of flare-accelerated electrons. However, past and current solar HXR observers lack the necessary sensitivity and imaging dynamic range to make detailed studies of faint HXR sources in the solar corona (where particle acceleration is thought to occur); these limitations are mainly due to the indirect Fourier imaging techniques used by these observers. With greater sensitivity and dynamic range, electron acceleration sites could be systematically studied in detail. Both these capabilities can be advanced by the use of direct focusing optics. The recently own Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload demonstrates the unique diagnostic power of focusing optics for observations of solar HXRs. FOXSI features grazing-incidence replicated nickel optics with ∼5 arcsecond resolution and fine-pitch silicon strip detectors with a ∼7.7 arcsecond strip pitch. FOXSI flew successfully on 2012 November 2, producing images and spectra of a microflare and performing a search for non-thermal emission (4{15 keV) from nanoflares occurring outside active regions in the quiet Sun. A future spacecraft version of FOXSI, featuring similar optics and detectors, could make detailed observations of HXRs from flare-accelerated electrons, identifying and characterizing particle acceleration sites and mapping out paths of energetic electrons as they leave these sites and propagate throughout the solar corona. This paper will describe the FOXSI instrument and present images from the first flight. © 2013 SPIE.

      DOI: 10.1117/12.2024277

      Scopus

      researchmap

    • Applications and imaging techniques of a Si/CdTe Compton gamma-ray camera 査読有り

      Shin'ichiro Takeda, Yuto Ichinohe, Kouichi Hagino, Hirokazu Odaka, Takayuki Yuasa, Shin-nosuke Ishikawa, Taro Fukuyama, Shinya Saito, Tamotsu Sato, Goro Sato, Shin Watanabe, Motohide Kokubun, Tadayuki Takahashi, Mitsutaka Yamaguchi, Hiroyasu Tajima, Takaaki Tanaka, Kazuhiro Nakazawa, Yasushi Fukazawa, Takashi Nakano

      PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON TECHNOLOGY AND INSTRUMENTATION IN PARTICLE PHYSICS (TIPP 2011)37   859 - 866   2012年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

      By using a new Compton camera consisting of a silicon double-sided strip detector (Si-DSD) and a CdTe double-sided strip detector (CdTe-DSD), originally developed for the ASTRO-H satellite mission, an experiment involving imaging radioisotopes was conducted to study their feasibility for hotspot monitoring. In addition to the hotspot imaging already provided by commercial imaging systems, identification of various radioisotopes is possible thanks to the good energy resolution obtained by the semiconductor detectors. Three radioisotopes of Ba-133 (356 keV), Na-22 (511 keV) and Cs-137 (662 keV) were individually imaged by applying event selection in the energy window and the gamma-ray images were correctly overlapped by an optical picture. Detection efficiency of 1.68 x10(-4) (effective area : 1.7 x10(-3) cm(2)) and angular resolution of 3.8 degrees were obtained by stacking five detector modules for a 662 keV gamma ray. The higher detection efficiency required in specific use can be achieved by stacking more detector modules. (C) 2012 Published by Elsevier B.V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.

      DOI: 10.1016/j.phpro.2012.04.096

      researchmap

    • Development of an integrated response generator for Si/CdTe semiconductor Compton cameras 査読有り

      Hirokazu Odaka, Soichiro Sugimoto, Shin-nosuke Ishikawa, Junichiro Katsuta, Yuu Koseki, Taro Fukuyama, Shinya Saito, Rie Sato, Goro Sato, Shin Watanabe, Motohide Kokubun, Tadayuki Takahashi, Shin'ichiro Takeda, Yasushi Fukazawa, Takaaki Tanaka, Hiroyasu Tajima

      NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT624 ( 2 ) 303 - 309   2010年12月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

      We have developed an integrated response generator based on Monte Carlo simulation for Compton cameras composed of silicon (Si) and cadmium telluride (CdTe) semiconductor detectors In order to construct an accurate detector response function the simulation is required to include a comprehensive treatment of the semiconductor detector devices and the data processing system in addition to simulating particle tracking Although CdTe is an excellent semiconductor material for detection of soft gamma rays its ineffective charge transport property distorts its spectral response We investigated the response of CdTe pad detectors in the simulation and present our initial results here We also performed the full simulation of prototypes of Si/CdTe semiconductor Compton cameras and report on the reproducibility of detection efficiencies and angular resolutions of the cameras both of which are essential performance parameters of astrophysical instruments (C) 2009 Elsevier B V All rights reserved

      DOI: 10.1016/j.nima.2009.11.052

      researchmap

    • Development of Double-Sided CdTe Strip Detectors for gamma-Ray Imaging and Spectroscopy 査読有り

      Shin-nosuke Ishikawa, Shin Watanabe, Taro Fukuyama, Goro Sato, Motohide Kokubun, Hirokazu Odaka, Shinya Saito, Tadayuki Takahashi, Kazuhiro Nakazawa, Takaaki Tanaka

      JAPANESE JOURNAL OF APPLIED PHYSICS49 ( 11 )   2010年11月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOC APPLIED PHYSICS  

      By reading out both anode and cathode strips, double-sided CdTe strip detectors can achieve a large area and a high position resolution with few readout channels, which makes them very attractive for X-ray and gamma-ray imaging and spectroscopy. We have developed double-sided CdTe strip detectors, 1.28 x 1.28 cm(2) in size and 0.5 and 2.0 mm in thickness. Both electrodes are divided into 32 orthogonal strips with a pitch of 400 gm. For a detector of 0.5 mm thickness, the energy resolution was measured to be 1.5 keV (FWHM) at 60 keV. For the 2.0-mm-thick detector, an energy resolution of 8.0 key (FWHM) at 662 key was obtained using only the anode signal. By combining both the anode and cathode signals, we successfully improved the spectral performance and measured an energy resolution of 5.9 keV (FWHM) at 662 key. (C) 2010 The Japan Society of Applied Physics

      DOI: 10.1143/JJAP.49.116702

      researchmap

    • Polarimetric performance of Si/CdTe semiconductor Compton camera 査読有り

      Shin'ichiro Takeda, Hirokazu Odaka, Junichiro Katsuta, Shin-nosuke Ishikawa, So-ichiro Sugimoto, Yuu Koseki, Shin Watanabe, Goro Sato, Motohide Kokubun, Tadayuki Takahashi, Kazuhiro Nakazawa, Yasushi Fukazawa, Hiroyasu Tajima, Hidenori Toyokawa

      NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT622 ( 3 ) 619 - 627   2010年10月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

      A Compton camera has been developed based on Si and CdTe semiconductor detectors with high spatial and spectral resolution for hard X- and gamma-ray astrophysics applications. A semiconductor Compton camera is also an excellent polarimeter due to its capability to precisely measure the Compton scattering azimuth angle, which is modulated by linear polarization. We assembled a prototype Compton camera and conducted a beam test using nearly 100% linearly polarized gamma-rays at SPring-8. (C) 2010 Elsevier B.V. All rights reserved.

      DOI: 10.1016/j.nima.2010.07.077

      researchmap

    • Development of double-sided silicon strip detectors for solar hard X-ray observation 査読有り

      Shinya Saito, Shin-nosuke Ishikawa, Shin Watanabe, Hirokazu Odaka, Soichiro Sugimoto, Taro Fukuyama, Motohide Kokubun, Tadayuki Takahashi, Yukikatsu Terada, Hiroyasu Tajima, Takaaki Tanaka, Saem Krucker, Steven Christe, Steve McBride, Lindsay Glesener

      SPACE TELESCOPES AND INSTRUMENTATION 2010: ULTRAVIOLET TO GAMMA RAY7732   2010年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

      The Focusing Optics X-ray Solar Imager (FOXSI) is a rocket experiment scheduled for January 2011 launch. FOXSI observes 5 - 15 keV hard X-ray emission from quiet-region solar flares in order to study the acceleration process of electrons and the mechanism of coronal heating. For observing faint hard X-ray emission, FOXSI uses focusing optics for the first time in solar hard X-ray observation, and attains 100 times higher sensitivity than RHESSI, which is the present solar hard X-ray observing satellite. Now our group is working on developments of both Double-sided Silicon Strip Detector (DSSD) and read-out analog ASIC "VATA451" used for FOXSI. Our DSSD has a very fine strip pitch of 75 mu m, which has sufficient position resolution for FOXSI mirrors with angular resolution (FWHM) of 12 arcseconds. DSSD also has high spectral resolution and efficiency in the FOXSI's energy range of 5 - 15 keV, when it is read out by our 64-channel analog ASIC. In advance of the FOXSI launch, we have established and tested a setup of 75 mu m pitch DSSD bonded with "VATA451" ASICs. We successfully read out from almost all the channels of the detector, and proved ability to make a shadow image of tungsten plate. We also confirmed that our DSSD has energy resolution (FWHM) of 0.5 keV, lower threshold of 5 keV, and position resolution less than 63 mu m. These performance satisfy FOXSI's requirements.

      DOI: 10.1117/12.857235

      researchmap

    • Development of a cadmium telluride pixel detector for astrophysical applications 査読有り

      Hiromasa Miyasaka, Fiona A. Harrison, Walter R. Cook, Peter H. Mao, Vikram R. Rana, Shin-Nosuke Ishikawa, Masayoshi Ushio, Hiroyuki Aono, Shin Watanabe, Goro Sato, Motohide Kokubun, Tadayuki Takahashi

      Proceedings of SPIE - The International Society for Optical Engineering7435   2009年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

      We are developing imaging Cadmium Telluride (CdTe) pixel detectors optimized for astrophysical hard X-ray applications. Our hybrid detector consist of a CdTe crystal 1mm thick and 2cm × 2cm in area with segmented anode contacts directly bonded to a custom low-noise application specific integrated circuit (ASIC). The CdTe sensor, fabricated by ACRORAD (Okinawa, Japan), has Schottky blocking contacts on a 605 micron pitch in a 32 × 32 array, providing low leakage current and enabling readout of the anode side. The detector is bonded using epoxy-gold stud interconnects to a custom low noise, low power ASIC circuit developed by Caltech's Space Radiation Laboratory. We have achieved very good energy resolution over a wide energy range (0.62keV FWHM @ 60keV, 10.8keV FWHM @ 662keV). We observe polarization effects at room temperature, but they are suppressed if we operate the detector at or below 0°C degree. These detectors have potential application for future missions such as the International X-ray Observatory (IXO). © 2009 Copyright SPIE - The International Society for Optical Engineering.

      DOI: 10.1117/12.825711

      Scopus

      researchmap

    • The Focusing Optics x-ray Solar Imager: FOXSI 査読有り

      Saem Krucker, Steven Christe, Lindsay Glesener, Steve McBride, Paul Turin, David Glaser, Pascal Saint-Hilaire, Gregory Delory, R. P. Lin, Mikhail Gubarev, Brian Ramsey, Yukikatsu Terada, Shin-nosuke Ishikawa, Motohide Kokubun, Shinya Saito, Tadayuki Takahashi, Shin Watanabe, Kazuhiro Nakazawa, Hiroyasu Tajima, Satoshi Masuda, Takashi Minoshima, Masumi Shomojo

      OPTICS FOR EUV, X-RAY, AND GAMMA-RAY ASTRONOMY IV7437   2009年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

      The Focusing Optics x-ray Solar Imager (FOXSI) is a sounding rocket payload funded under the NASA Low Cost Access to Space program to test hard x-ray focusing optics and position-sensitive solid state detectors for solar observations. Today's leading solar hard x-ray instrument, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) provides excellent spatial (2 arcseconds) and spectral (1 keV) resolution. Yet, due to its use of indirect imaging, the derived images have a low dynamic range (< 30) and sensitivity. These limitations make it difficult to study faint x-ray sources in the solar corona which are crucial for understanding the solar flare acceleration process. Grazing-incidence x-ray focusing optics combined with position-sensitive solid state detectors can overcome both of these limitations enabling the next breakthrough in understanding particle acceleration in solar flares. The FOXSI project is led by the Space Science Laboratory at the University of California. The NASA Marshall Space Flight Center, with experience from the HERO balloon project, is responsible for the grazing-incidence optics, while the Astro H team (JAXA/ISAS) will provide double-sided silicon strip detectors. FOXSI will be a pathfinder for the next generation of solar hard x-ray spectroscopic imagers. Such observatories will be able to image the non-thermal electrons within the solar flare acceleration region, trace their paths through the corona, and provide essential quantitative measurements such as energy spectra, density, and energy content in accelerated electrons.

      DOI: 10.1117/12.827950

      researchmap

    • Hard X-ray Imager (HXI) for the NeXT mission 査読有り

      Motohide Kokubun, Kazuhiro Nakazawa, Shin Watanabe, Yasushi Fukazawa, Jun Kataoka, Hideaki Katagiri, Tsunefumi Mizuno, Kazuo Makishima, Masanori Ohno, Goro Sato, Rie Sato, Hiroyasu Tajima, Tadayuki Takahashi, Toru Tamagawa, Takaaki Ta Na Ka, Makoto Tashiro, Hiromitsu Takahashi, Yukikatsu Terada, Yasunobu Uchiyama, Yuji Urata, Kazutaka Yamaoka, Shin'ichiro Takeda, Tetsuichi Kishishita, Masayoshi Ushio, Jun'ichiro Katsuta, Shin'nosuke Ishikawa, Hirokazu Odaka, Hiroyuki Aono, Souichiro Sugimoto, Yuu Koseki, Takao Kitaguchi, Teruaki Enoto, Shin'ya Yamada, Takayuki Yuasa, Tsuyoshi Ueda, Yuichi Uehara, Sho Okuyama, Hajimu Yasuda, Sho Nishino, Yudai Umeki, Katsuhiro Hayashi, Masayuki Matsuoka, Yuki Ikejiri, Akira Endo, Yuichi Yaji, Natsuki Kodaka, Wataru Iwakiri, Tomomi Kouzu, Takako Sugasawara, Atsushi Harayama, Satoshi Nakahira

      Proceedings of SPIE - The International Society for Optical Engineering7011   2008年

      詳細を見る

      掲載種別:研究論文(国際会議プロシーディングス)  

      The Hard X-ray Imager (HXI) is one of three focal plane detectors on board the NeXT (New exploration X-ray Telescope) mission, which is scheduled to be launched in 2013. By use of the hybrid structure composed of double-sided silicon strip detectors and a cadmium telluride strip detector, it fully covers the energy range of photons collected with the hard X-ray telescope up to 80 keV with a high quantum efficiency. High spatial resolutions of 400 micron pitch and energy resolutions of 1-2 keV (FWMH) are at the same time achieved with low noise front-end ASICs. In addition, thick BGO active shields compactly surrounding the main detection part, as a heritage of the successful performance of the Hard X-ray Detector (HXD) on board Suzaku satellite, enable to achive an extremely high background reduction for the cosmic-ray particle background and in-orbit activation. The current status of hardware development including the design requirement, expected performance, and technical readinesses of key technologies are summarized.

      DOI: 10.1117/12.788290

      Scopus

      researchmap

    • Application of double-sided silicon strip detectors to Compton cameras 査読有り

      Hiroyuki Aono, Shin'ichiro Takeda, Shin-nosuke Ishikawa, Hirokazu Odaka, Motohide Kokubun, Shin Watanabe, Tadayuki Takahashi, Kazuhiro Nakazawa, Sho Okuyama, Hiroyasu Tajima, Yasushi Fukazawa, Naoki Kawachi

      HIGH ENERGY, OPTICAL, AND INFRARED DETECTORS FOR ASTRONOMY III7021   2008年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

      We have developed a Compton camera with a double-sided silicon strip detector (DSSD) for hard X-ray and gamma-ray observation. Using a DSSD as a scatter detector of the Compton camera., we achieved high angular resolution of 3.4 at 511 keV. Through the imaging of various samples such as two-dimentional array sources and a diffuse source, the wide field-of-view (similar to 100 degrees) and the high spatial resolution (at; least 20 mm at a distance; of 60 mm from the DSSD) of the camera were confirmed. Furthermore, using the List; Mode Maximum-Likelihood Expectation-Maximization method, the camera can resolve ail interval of 3 mm at a distance of 30 mm from the DSSD.

      DOI: 10.1117/12.788784

      researchmap

    • Performance study of Si/CdTe semiconductor Compton telescopes with Monte Carlo simulation 査読有り

      Hirokazu Odaka, Shin'ichiro Takeda, Shin Watanabe, Shin-nosuke Ishikawa, Masayoshi Ushio, Takaaki Tanaka, Kazuhiro Nakazawa, Tadayuki Takahashi, Hiroyasu Tajima, Yasushi Fukazawa

      NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT579 ( 2 ) 878 - 885   2007年9月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

      A Compton telescope with high angular resolution and high energy resolution is a promising detector for the next generation of astrophysics space missions aiming at hard X-rays and sub-MeV/MeV gamma-rays. We have been working on a semiconductor Compton camera based on silicon and cadmium telluride (Si/CdTe Compton telescope). The soft gamma-ray detector (SGD) employs a Si/CdTe Compton camera combined with a well-type active shield. It will be mounted on the NeXT mission, proposed to be launched around 2012. One Compton camera module in the SGD will consist of 24 layers of double-sided silicon strip detectors and four layers of CdTe pixel detectors. We carried out Monte Carlo simulations to investigate the basic performance of the detector. Design parameters of devices required in the simulation, such as energy resolution and position resolution of the detector, are based on the results from our prototype detector. From the simulation using current design parameters, the detection efficiency is found to be higher than 10% at similar to 100keV and the angular resolution to be 9 degrees and 4.4 degrees at 120keV and 330keV, respectively. The effects of changing the design parameters are also discussed. (c) 2007 Published by Elsevier B.V.

      DOI: 10.1016/j.nima.2007.05.293

      researchmap

    • Development of semiconductor imaging detectors for a Si/CdTe Compton camera 査読有り

      Shin Watanabe, Shin'ichiro Takeda, Shin-nosuke Ishikawa, Hirokazu Odaka, Masayoshi Ushio, Takaaki Tanaka, Kazuhiro Nakazawa, Tadayuki Takahashi, Hiroyasu Tajima, Yasushi Fukazawa, Yoshikatsu Kuroda, Mitsunobu Onishi

      NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT579 ( 2 ) 871 - 877   2007年9月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

      Si and CdTe semiconductor imaging detectors have been developed for use in a Si/CdTe Compton camera. Based on a previous study using the first prototype of a Si/CdTe Compton camera, new detector modules have been designed to upgrade the performance of the Compton camera. As the scatter detector of the Compton camera, a stack of double-sided Si strip detector (DSSD) modules, which has four layers with a stack pitch of 2mm, was constructed. By using the stack DSSDs, an energy resolution of 1.5keV (FWHM) was achieved. For the absorber detector, the CdTe pixel detector modules were built and a CdTe pixel detector stack using these modules was also constructed. A high energy resolution (Delta E/E similar to 1%) was achieved. The improvement of the detection efficiency by stacking the modules has been confirmed by tests of the CdTe stack. Additionally, a large area CdTe imager is introduced as one application of the CdTe pixel detector module. (c) 2007 Elsevier B.V. All rights reserved.

      DOI: 10.1016/j.nima.2007.05.306

      researchmap

    • New CdTe pixel gamma-ray detector with pixelated Al schottky anodes 査読有り

      Shin Watanabe, Shin-nosuke Ishikawa, Shin'ichiro Takeda, Hirokazu Odaka, Takaaki Tanaka, Tadayuki Takahashi, Kazuhiro Nakazawa, Masaaki Yamazato, Akira Higa, Sakari Kaneku

      JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS46 ( 9A ) 6043 - 6045   2007年9月

      詳細を見る

      記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INST PURE APPLIED PHYSICS  

      We developed a new At Schottky CdTe pixel detector and measured its spectral performance. It has pixelated anodes made of aluminum and a common cathode made of platinum. Because of the low leakage current and the high bias voltage owing to the Schottky diode characteristic and the anode pixel configuration, a good spectral performance including a high energy resolution was achieved. When the pixel detector with a thickness of 0.75 mm was subjected to a bias voltage of 400 V and was operated at -20 degrees C, the full-width-half-maximum (FWHM) energy resolution of 1.1 and 1.8keV at 59.5 and 122keV, respectively, were successfully obtained. The spectral performance obtained with the At Schottky CdTe pixel detector exceeded that obtained with the conventional In Schottky CdTe pixel detector, which has an In common anode and Pt pixelated cathodes, under the same operating conditions.

      DOI: 10.1143/JJAP.46.6043

      researchmap

    • Performance measurements of Al/CdTe/Pt pixel diode detectors 査読有り

      Shin-nosuke Ishikawa, Hiroyuki Aono, Shin Watanabe, Shin'ichiro Takeda, Kazuhiro Nakazawa, Tadayuki Takahashi

      HARD X-RAY AND GAMMA-RAY DETECTOR PHYSICS IX6706   2007年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

      We developed Schottky CdTe detectors using At as an anode electrode and measured their performances. We first fabricated monolithic detectors with four different thicknesses of 0.5, 0.75, 1.0, and 2.0 mm. An At anode electrode was implemented with a guard-ring structure. For the 0.5 mm thick CdTe detector, an energy resolution of 1.2 keV (FWHM) at 122 keV was achieved at a temperature of -20 degrees C and a bias voltage of 400 V. Using the same technology, we next developed 8 x 8 pixel Me detectors, again with the four different thicknesses. The At anode electrode was pixelated and the Pt cathode was made as a, single plate. Signals from all pixels were successfully obtained and all energy resolution of 1.3 keV and 1.9 keV (FWHM) for 59.5 keV and 122 keV gamma-rays. was achieved at a temperature of -20 degrees C and a bias voltage of 400 V using the 0.5 mm thick CdTe detector. The energy resolution was nearly the same in each pixel.

      DOI: 10.1117/12.735188

      researchmap

    • A new Si/CdTe semiconductor Compton camera developed for high-angular resolution 査読有り

      Shin'ichiro Takeda, Shin-nosuke Ishikawa, Hirokazu Odaka, Shin Watanabe, Tadayuki Takahashi, Kazuhiro Nakazawa, Hiroyasu Tajima, Yoshikatsu Kuroda, Mitsunobu Onishi, Yasushi Fakazawa, Hajimu Yasuda

      HARD X-RAY AND GAMMA-RAY DETECTOR PHYSICS IX6706   2007年

      詳細を見る

      記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

      A semiconductor Compton camera for a balloon borne experiment aiming at observation in high energy astrophysics is developed. The camera is based on the concept of the Si/CdTe semiconductor Compton Camera, which features high-energy and high-angular resolution in the energy range from several tens of keV to a few MeV. It consists of tightly packed double-sided silicon strip detectors (DSSDs) stacked in four layers, and a total of 32 CdTe pixel detectors surrounding them. The Compton reconstruction was successfully performed and gamma-ray images were obtained from 511 keV down to 59.5 keV. The Angular Resolution Measure (ARM) at 511 keV is similar to 2.5 degrees, thanks to the high energy resolution in both the DSSD and CdTe parts.

      DOI: 10.1117/12.733840

      researchmap

    ▼全件表示

    共同研究・競争的資金等の研究

    • 高感度X線撮像分光観測による太陽高エネルギープラズマの探査

      日本学術振興会  科学研究費助成事業 

      石川 真之介

      詳細を見る

      2017年4月 - 2021年3月

      課題番号:17H04832

      配分額:24960000円 ( 直接経費:19200000円 、 間接経費:5760000円 )

      本年度、本研究課題の中心となる実験 Focusing Optics Solar X-ray Imager の3回目の打ち上げ (FOXSI-3) を実施し、photon-counting の手法により、0.5-5 keV の軟X線領域において太陽の撮像分光観測を世界で初めて実現した。FOXSI-3 の打ち上げは2018年9月7日に米国ニューメキシコ州ホワイトサンズから行われ、弾道飛行中に予定通りおよそ6分間太陽を観測し、ほぼ太陽全面にわたって撮像分光データを取得することに成功した。FOXSI-3 ロケット実験の成功は、研究課題である「高感度X線撮像分光観測による太陽高エネルギープラズマの探査」を実現したことに他ならない。これまで技術的に困難であった、太陽における諸現象の空間スケールをカバーし、それらの現象の時間スケールを分解できる高い時間分解能は、本研究において開発した高速 CMOS 撮像分光システムにより可能となった。FOXSI-3 により、巨大フレアが発生している時間帯以外においても、コロナの高エネルギープラズマが発するX線連続スペクトルの放射と、高エネルギープラズマ中のイオンによる線スペクトルの放射を別々に定量評価することが太陽で初めて可能となり、平衡状態を仮定する従来の手法では得られなかった新たな情報を得ることができると考えられる。本研究の成果を発展させ、観測衛星計画 PhoENiX により高感度太陽X線撮像分光観測を進める。

      researchmap

    • 太陽コロナ観測用・光子計測型・撮像分光X線望遠鏡に向けた光子計測システムの開発

      日本学術振興会  科学研究費助成事業 

      成影 典之, 石川 真之介, 坂尾 太郎

      詳細を見る

      2015年4月 - 2018年3月

      課題番号:15H03647

      配分額:17030000円 ( 直接経費:13100000円 、 間接経費:3930000円 )

      本研究を通し、太陽コロナからの軟X線を2次元撮像分光観測するための光子計測システムを完成させた。このシステムは、X線光子計測能力を有する高速駆動可能な「裏面照射型CMOS検出器」と、この検出器を高速駆動し大量のデータを保存することが可能な「高速データ収集ボード」から構成されている。
      このシステムは、2018年8月下旬に打ち上げ予定の米国NASAの観測ロケット実験FOXSI-3に搭載し、世界初となる太陽軟X線の2次元集光撮像分光観測を実施する。

      researchmap

    • 高精度ロケットを用いた太陽の硬X線撮像観測による相対論的現象の探査・解明

      日本学術振興会  科学研究費助成事業 

      高橋 忠幸, 渡辺 伸, 石川 真之介

      詳細を見る

      2012年4月 - 2016年3月

      課題番号:24244021

      配分額:41470000円 ( 直接経費:31900000円 、 間接経費:9570000円 )

      世界初の太陽高感度硬X線撮像分光観測を行うため、日米共同で観測ロケット実験(FOXSI) を行い、2回の太陽コロナの高感度観測に成功した。我々は焦点面検出器およびキャリブレーションや現地作業を担当した。FOXSI-1では、太陽外縁部で発生したマイクロフレアを観測し、RHESSI 衛星と比べて極めて高い感度を発揮できていることを確認した。FOXSI-2 では、CdTeセンサーを開発することでFOXSI-1 よりも感度、有効面積が大きく向上した。本研究では硬X線望遠鏡システムを用いることで、従来の観測では極めて困難であった高ダイナミックレンジの太陽撮像観測に成功した。

      researchmap

    お問い合わせ先
    外部の方
    学内の方