Updated on 2022/09/15

写真a

 
MASUDA Takahiko
 
Organization
Research Institute for Interdisciplinary Science Special-Appointment Associate Professor
Position
Special-Appointment Associate Professor
External link

Degree

  • 博士(理学) ( 京都大学 )

Research Interests

  • えdm

  • Muonium

  • neutrino

  • Kaon

  • Thorium

Research Areas

  • Natural Science / Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics

  • Natural Science / Semiconductors, optical properties of condensed matter and atomic physics

Education

  • Kyoto University   大学院理学研究科   物理・宇宙物理学専攻

    2009.4 - 2014.3

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    Country: Japan

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  • Kyoto University   理学研究科   物理・宇宙物理学専攻

    2007.4 - 2009.3

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    Country: Japan

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  • Kyoto University   理学部   理学科

    2003.4 - 2007.3

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Research History

  • Harvard University   Faculty of Arts and Sciences   Associate

    2021.8

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    Country:United States

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  • Okayama University   Research Institute for Interdisciplinary Science   Project Associate Professor

    2019.11

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  • Riken   Visited researcher

    2018.7

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  • Okayama University   Research Institute for Interdisciplinary Science   Senior Assistant Professor

    2017.12 - 2019.10

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  • Okayama University   Research Institute for Interdisciplinary Science   Assistant Professor

    2016.4 - 2017.11

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  • Okayama University   Research Core of Extreme Quantum World   Assistant Professor

    2014.4 - 2016.3

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Professional Memberships

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Committee Memberships

  • Japan Association of High Energy Physicists   High energy news editorial board  

    2021.4   

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    Committee type:Other

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  • Japan Association of High Energy Physicists   High Energy News Editorial Chair  

    2020.4 - 2021.3   

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    Committee type:Academic society

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Papers

  • Estimation of radiative half-life of Th229m by half-life measurement of other nuclear excited states in Th229 Reviewed International journal

    Y. Shigekawa, A. Yamaguchi, K. Suzuki, H. Haba, T. Hiraki, H. Kikunaga, T. Masuda, S. Nishimura, N. Sasao, A. Yoshimi, K. Yoshimura

    Physical Review C   104 ( 2 )   024306   2021.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    We perform coincidence measurements between a particles and. rays from a U-233 source to determine the half-lives of the excited state in a Th-229 nucleus. We first prove that the half-lives of 42.43- and 164.53-keV states are consistent with literature values, whereas that of the 97.14-keV state [93(7) ps] deviates from a previously measured value [147(12) ps]. The half-lives of 71.83- and 163.25-keV states are determined for the first time. Based on the obtained half-lives and the Alaga rule, we estimate the radiative half-life of the low-energy isomeric state (Th-229m) to be 5.0(11) x 10(3) s, which is one of the key parameters for the frequency standard based on Th-229.

    DOI: 10.1103/physrevc.104.024306

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    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevC.104.024306/fulltext

  • Suppression of the optical crosstalk in a multi-channel silicon photomultiplier array Reviewed International coauthorship International journal

    Takahiko Masuda, Daniel G. Ang, Nicholas R. Hutzler, Cole Meisenhelder, Noboru Sasao, Satoshi Uetake, Xing Wu, David DeMille, Gerald Gabrielse, John M. Doyle, Koji Yoshimura

    Optics Express   29 ( 11 )   16914 - 16914   2021.5

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Optical Society  

    DOI: 10.1364/oe.424460

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  • Simulation Study of Laser Ionization of Muonium by 1S-2S Excitation for the Muon g − 2/EDM Experiment at J-PARC Reviewed International coauthorship International journal

    Ce Zhang, Hideaki Hara, Takahiro Hiraki, Yutaka Ikedo, Yasutaka Imai, Katsuhiko Ishida, Saeid Kamal, Naritoshi Kawamura, Akihiro Koda, Yajun Mao, Takahiko Masuda, Tsutomu Mibe, Yasuhiro Miyake, Yuki Miyamoto, Yu Oishi, Masashi Otani, Patrick Strasser, Koichiro Shimomura, Kazuhito Suzuki, Satoshi Uetake, Takayuki Yamazaki, Shinsuke Yamamoto, Koji Yoshimura, Mitsuhiro Yoshida

    JPS Conf. Proc.   33   011125   2021.3

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Journal of the Physical Society of Japan  

    DOI: 10.7566/jpscp.33.011125

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  • Study of the KL→π0νν¯ Decay at the J-PARC KOTO Experiment Reviewed

    J. K. Ahn, B. Beckford, M. Campbell, S. H. Chen, J. Comfort, K. Dona, M. S. Farrington, K. Hanai, N. Hara, H. Haraguchi, Y. B. Hsiung, M. Hutcheson, T. Inagaki, M. Isoe, I. Kamiji, T. Kato, E. J. Kim, J. L. Kim, H. M. Kim, T. K. Komatsubara, K. Kotera, S. K. Lee, J. W. Lee, G. Y. Lim, Q. S. Lin, C. Lin, Y. Luo, T. Mari, T. Masuda, T. Matsumura, D. Mcfarland, N. McNeal, K. Miyazaki, R. Murayama, K. Nakagiri, H. Nanjo, H. Nishimiya, Y. Noichi, T. Nomura, T. Nunes, M. Ohsugi, H. Okuno, J. C. Redeker, J. Sanchez, M. Sasaki, N. Sasao, T. Sato, K. Sato, Y. Sato, N. Shimizu, T. Shimogawa, T. Shinkawa, S. Shinohara, K. Shiomi, R. Shiraishi, S. Su, Y. Sugiyama, S. Suzuki, Y. Tajima, M. Taylor, M. Tecchio, M. Togawa, T. Toyoda, Y.-C. Tung, Q. H. Vuong, Y. W. Wah, H. Watanabe, T. Yamanaka, H. Y. Yoshida, L. Zaidenberg

    Physical Review Letters   126 ( 12 )   121801   2021.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    The rare decay KL was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of (7.20±0.05stat±0.66syst)×10-10, three candidate events were observed in the signal region. After unveiling them, contaminations from K± and scattered KL decays were studied, and the total number of background events was estimated to be 1.22±0.26. We conclude that the number of observed events is statistically consistent with the background expectation. For this dataset, we set an upper limit of 4.9×10-9 on the branching fraction of KL→ π0ν ν at the 90% confidence level.

    DOI: 10.1103/physrevlett.126.121801

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    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.126.121801/fulltext

  • Pulse shape discrimination of photons and neutrons in the energy range of 0.1 – 2 GeV with the KOTO un-doped CsI calorimeter Reviewed International coauthorship International journal

    Y. Sugiyama, J.K. Ahn, S. Banno, B. Beckford, M. Campbell, S.H. Chen, J. Comfort, Y.T. Duh, T. Hineno, Y.B. Hsiung, M. Hutcheson, E. Iwai, I. Kamiji, N. Kawasaki, E.J. Kim, J.L. Kim, Y.J. Kim, J.W. Ko, T.K. Komatsubara, A.S. Kurilin, J.W. Lee, S.K. Lee, G.Y. Lim, C. Lin, Q. Lin, Y. Luo, J. Ma, Y. Maeda, T. Masuda, T. Matsumura, D. Mcfarland, R. Murayama, D. Naito, K. Nakagiri, Y. Nakaya, H. Nanjo, T. Nomura, Y. Odani, J.C. Redeker, Y.D. Ri, N. Sasao, K. Sato, S. Seki, T. Shimogawa, T. Shinkawa, S. Shinohara, K. Shiomi, S. Su, S. Suzuki, Y. Tajima, G. Takahashi, Y. Takashima, M. Tecchio, M. Togawa, Y.C. Tung, Y.W. Wah, H. Watanabe, N. Whallon, J.K. Woo, J. Xu, T. Yamanaka, Y. Yanagida, H.Y. Yoshida, H. Yoshimoto

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   987   164825 - 164825   2021.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    A pulse shape difference between photons and neutrons was observed in the output signals of scintillation light from the un-doped CsI calorimeter of the KOTO experiment for the KL→π0νν̄ decay. We developed a discrimination method to reject neutrons and to accept photons in the deposited energy range from 0.1 to 2 GeV. The method rejects 67% of neutron-induced single hadronic clusters and 86% of neutron-induced two-cluster events while keeping more than 90% of photon-induced single electromagnetic clusters and two-photon events.

    DOI: 10.1016/j.nima.2020.164825

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  • Absolute X-ray energy measurement using a high-accuracy angle encoder Reviewed International coauthorship International journal

    Takahiko Masuda, Tsukasa Watanabe, Kjeld Beeks, Hiroyuki Fujimoto, Takahiro Hiraki, Hiroyuki Kaino, Shinji Kitao, Yuki Miyamoto, Koichi Okai, Noboru Sasao, Makoto Seto, Thorsten Schumm, Yudai Shigekawa, Kenji Tamasaku, Satoshi Uetake, Atsushi Yamaguchi, Yoshitaka Yoda, Akihiro Yoshimi, Koji Yoshimura

    Journal of Synchrotron Radiation   28 ( 1 )   111 - 119   2021.1

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:International Union of Crystallography (IUCr)  

    This paper presents an absolute X-ray photon energy measurement method that uses a Bond diffractometer. The proposed system enables the prompt and rapid <italic>in situ</italic> measurement of photon energies over a wide energy range. The diffractometer uses a reference silicon single-crystal plate and a highly accurate angle encoder called SelfA. The performance of the system is evaluated by repeatedly measuring the energy of the first excited state of the potassium-40 nuclide. The excitation energy is determined as 29829.39 (6) eV, and this is one order of magnitude more accurate than the previous measurement. The estimated uncertainty of the photon energy measurement was 0.7 p.p.m. as a standard deviation and the maximum observed deviation was 2 p.p.m.

    DOI: 10.1107/s1600577520014526

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  • CsI calorimeter for the J-PARC KOTO experiment Reviewed International coauthorship International journal

    K. Sato, J.W. Lee, S. Banno, M. Campbell, J. Comfort, T. Furukawa, E. Iwai, N. Kawasaki, T.K. Komatsubara, G.Y. Lim, Y. Maeda, T. Masuda, T. Matsumura, D. Mcfarland, R. Murayama, D. Naito, Y. Nakaya, H. Nanjo, T. Nomura, Y. Odani, T. Ota, Y.D. Ri, M. Sasaki, N. Sasao, S. Seki, T. Shimogawa, T. Shinkawa, K. Shiomi, Y. Sugiyama, S. Suzuki, Y. Tajima, M. Tecchio, M. Togawa, T. Yamanaka, Y. Yanagida, H. Yokota, H. Yoshimoto, Y.W. Wah, H. Watanabe, J. Xu

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   982   164527 - 164527   2020.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    An electromagnetic calorimeter made of undoped CsI crystals is used in the J-PARC KOTO experiment to search for new physics beyond the standard model with the KL→π0νν̄ decay. The calorimeter is designed to operate in vacuum of 0.1 Pa and in a high-rate environment where the counting rate due to KL decays is O(100) kHz. A special method to calibrate the calorimeter during the data taking without using a tracking system for charged particles is reported. The energy, position, and timing resolutions of the calorimeter were evaluated in several beam tests, and the resolutions satisfy the required performance. The energy resolution with the total energy E is 0.66⊕1.81∕E[GeV]% in the inner region of the calorimeter.

    DOI: 10.1016/j.nima.2020.164527

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  • Geometry-dependent spectra and coherent-transient measurement of nearly degenerate four-wave mixing using two-photon resonance Reviewed

    Hara Hideaki, Miyamoto Yuki, Hiraki Takahiro, Imamura Kei, Masuda Takahiko, Sasao Noboru, Uetake Satoshi, Yoshimi Akihiro, Yoshimura Koji, Yoshimura Motohiko

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   52 ( 23 )   2019.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    We study nearly degenerate four-wave mixing using a two-photon-allowed vibrational transition of parahydrogen. A signal photon is generated by a trigger photon and coherence among parahydrogen, which is prepared by two counterpropagating pump pulses, and we investigate the dependence of the signal pulse energy on the trigger frequency. The measured spectra depend on the geometry, shifting depending on the direction of the signal pulse and on the small angle formed by the counterpropagating pump pulses. Furthermore, we investigate the dependence of signal pulse energy on the incident time of the trigger pulse. The measured signal pulse energy is high if the trigger pulse is delayed slightly with respect to the pump pulses. We demonstrate that these geometry-dependent spectra and coherent-transient response can be explained by using simple models.

    DOI: 10.1088/1361-6455/ab4a6e

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  • Fast APD Detector with a Short Tail in the Timing Response for an Experiment Using Synchrotron Radiation X-ray Beam Reviewed

    JPS Conference Proceedings   2019.11

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    DOI: 10.7566/jpscp.27.012020

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  • Development of a measurement system enabling the reconstruction of gamma-ray time spectra by simultaneous recording of energy and time information Reviewed

    Tajima Hiroyuki, Kitao Shinji, Masuda Ryo, Kobayashi Yasuhiro, Masuda Takahiko, Yoshimura Koji, Seto Makoto

    JAPANESE JOURNAL OF APPLIED PHYSICS   58 ( 10 )   2019.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    We developed a measurement system that enables the reconstruction of gamma-ray time spectra in cascade decay schemes with 0.3 ns time resolution, which is sufficient for nuclear decay with more than nanoseconds half-life. As this system records all the time and energy information of gamma-rays, the energy regions for the gamma-ray identification can be optimized after the measurement. Moreover, this system has five timing inputs and thus we can record the timing data of external perturbations; we can investigate the responses to the perturbation afterward. This property fulfills the demands required for quantum information research with gamma-rays. (C) 2019 The Japan Society of Applied Physics

    DOI: 10.7567/1347-4065/ab3f19

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  • X-ray pumping of the 229Th nuclear clock isomer Reviewed

    Takahiko Masuda, Akihiro Yoshimi, Akira Fujieda, Hiroyuki Fujimoto, Hiromitsu Haba, Hideaki Hara, Takahiro Hiraki, Hiroyuki Kaino, Yoshitaka Kasamatsu, Shinji Kitao, Kenji Konashi, Yuki Miyamoto, Koichi Okai, Sho Okubo, Noboru Sasao, Makoto Seto, Thorsten Schumm, Yudai Shigekawa, Kenta Suzuki, Simon Stellmer, Kenji Tamasaku, Satoshi Uetake, Makoto Watanabe, Tsukasa Watanabe, Yuki Yasuda, Atsushi Yamaguchi, Yoshitaka Yoda, Takuya Yokokita, Motohiko Yoshimura, Koji Yoshimura

    Nature   573 ( 7773 )   238 - 242   2019.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1038/s41586-019-1542-3

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  • Search for KL→π0νν¯ and KL→π0X0 Decays at the J-PARC KOTO Experiment Reviewed

    J. K. Ahn, B. Beckford, J. Beechert, K. Bryant, M. Campbell, S. H. Chen, J. Comfort, K. Dona, N. Hara, H. Haraguchi, Y. B. Hsiung, M. Hutcheson, T. Inagaki, I. Kamiji, N. Kawasaki, E. J. Kim, J. L. Kim, Y. J. Kim, J. W. Ko, T. K. Komatsubara, K. Kotera, A. S. Kurilin, J. W. Lee, G. Y. Lim, C. Lin, Q. Lin, Y. Luo, J. Ma, Y. Maeda, T. Mari, T. Masuda, T. Matsumura, D. Mcfarland, N. McNeal, J. Micallef, K. Miyazaki, R. Murayama, D. Naito, K. Nakagiri, H. Nanjo, H. Nishimiya, T. Nomura, M. Ohsugi, H. Okuno, M. Sasaki, N. Sasao, K. Sato, T. Sato, Y. Sato, H. Schamis, S. Seki, N. Shimizu, T. Shimogawa, T. Shinkawa, S. Shinohara, K. Shiomi, S. Su, Y. Sugiyama, S. Suzuki, Y. Tajima, M. Taylor, M. Tecchio, M. Togawa, Y. C. Tung, Y. W. Wah, H. Watanabe, J. K. Woo, T. Yamanaka, H. Y. Yoshida

    Physical Review Letters   122 ( 2 )   021802   2019.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    DOI: 10.1103/physrevlett.122.021802

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    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.122.021802/fulltext

  • Coherent two-photon emission from hydrogen molecules excited by counter-propagating laser pulses Reviewed

    Hiraki Takahiro, Hara Hideaki, Miyamoto Yuki, Imamura Kei, Masuda Takahiko, Sasao Noboru, Uetake Satoshi, Yoshimi Akihiro, Yoshimura Koji, Yoshimura Motohiko

    Journal of Physics B: Atomic, Molecular and Optical Physics   52 ( 4 )   045401   2019.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    We observed two-photon emission (TPE) signal from the first vibrationally excited state of parahydrogen gas coherently excited by counter-propagating laser pulses. A single narrow-linewidth laser source has roles in the excitation of the parahydrogen molecules and the induction of the TPE process. We measured dependences of the signal energy on the detuning, target gas pressure, and input pulse energies. These results are qualitatively consistent with those obtained by numerical simulations based on Maxwell-Bloch equations with one spatial dimension and one temporal dimension. This study of the TPE process in the counterpropagating injection scheme is an important step toward neutrino mass spectroscopy.

    DOI: 10.1088/1361-6455/aafbd0

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  • Energy response of X-rays under high flux conditions using a thin APD for the energy range of 6-33 keV Reviewed

    T. Masuda, T. Hiraki, H. Kaino, S. Kishimoto, Y. Miyamoto, K. Okai, S. Okubo, R. Ozaki, N. Sasao, K. Suzuki, S. Uetake, A. Yoshimi, K. Yoshimura

    Nuclear Instruments and Methods in Physics Research A   913   72 - 77   2018.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    This paper reports on the demonstration of a high-rate energy measurement technique using a thin depletion layer silicon avalanche photodiode (Si-APD). A dedicated amplitude-to-time converter is developed to realize simultaneous energy and timing measurement in a high rate condition. The energy response of the system is systematically studied by using monochromatic X-ray beam with an incident energy ranging from 6 to 33 keV. The obtained energy spectra contain clear peaks and tail distributions. The peak fraction monotonously decreases as the incident photon energy increases. This phenomenon can be explained by considering the distribution of the energy deposit in silicon, which is investigated by using a Monte Carlo simulation.

    DOI: 10.1016/j.nima.2018.10.029

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  • Nuclear resonant scattering experiment with fast time response: Photonuclear excitation of Hg 201 Reviewed

    A. Yoshimi, H. Hara, T. Hiraki, Y. Kasamatsu, S. Kitao, Y. Kobayashi, K. Konashi, R. Masuda, T. Masuda, Y. Miyamoto, K. Okai, S. Okubo, R. Ozaki, N. Sasao, O. Sato, M. Seto, T. Schumm, Y. Shigekawa, S. Stellmer, K. Suzuki, S. Uetake, M. Watanabe, A. Yamaguchi, Y. Yasuda, Y. Yoda, K. Yoshimura, M. Yoshimura

    Physical Review C   97 ( 2 )   2018.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society  

    Nuclear resonant excitation and detection of its decay signal for the 26.27-keV level of Hg201 is demonstrated with high-brilliance synchrotron radiation (SR) and a fast x-ray detector system. This SR-based photonuclear excitation scheme, known as nuclear resonant scattering (NRS) in the field of materials science, is also useful for investigating nuclear properties, such as the half-lives and radiative widths of excited nuclear levels. To date, because of the limited time response of the x-ray detector, the nuclear levels to which this method could be applied have been limited to the one whose half-lives are longer than ∼1 ns. The faster time response of the NRS measurement makes possible NRS experiments on nuclear levels with much shorter half-lives. We have fabricated an x-ray detector system that has a time resolution of 56 ps and a shorter tail function than that reported previously. With the implemented detector system, the NRS signal of the 26.27-keV state of Hg201 could be clearly discriminated from the electronic scattering signal at an elapsed time of 1 ns after the SR pulse. The half-life of the state was determined as 629 ± 18 ps, which has better precision by a factor of three compared with that reported to date obtained from nuclear decay spectroscopy.

    DOI: 10.1103/PhysRevC.97.024607

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    Other Link: http://orcid.org/0000-0001-8122-5145

  • Vibrational excitation of hydrogen molecules by two-photon absorption and third-harmonic generation Reviewed

    Yuki Miyamoto, Hideaki Hara, Takahiro Hiraki, Takahiko Masuda, Noboru Sasao, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS   51 ( 1 )   2018.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    We report the coherent excitation of the vibrational state of hydrogen molecules by two-photon absorption and the resultant third-harmonic generation (THG). Parahydrogen molecules cooled by liquid nitrogen are irradiated by mid-infrared nanosecond pulses at 4.8 mu m with a nearly Fourier-transform-limited linewidth. The first excited vibrational state of parahydrogen is populated by two-photon absorption of the mid-infrared photons. Because of the narrow linewidth of the mid-infrared pulses, coherence between the ground and excited states is sufficient to induce higher-order processes. Near-infrared photons from the THG are observed at 1.6 mu m. The dependence of the intensity of the near-infrared radiation on mid-infrared pulse energy, target pressure, and cell length is determined. We used a simple formula for THG with consideration of realistic experimental conditions to explain the observed results.

    DOI: 10.1088/1361-6455/aa9782

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    Other Link: http://orcid.org/0000-0001-8122-5145

  • Frequency dependence of coherently amplified two-photon emission from hydrogen molecules Reviewed

    Hideaki Hara, Yuki Miyamoto, Takahiro Hiraki, Takahiko Masuda, Noboru Sasao, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    PHYSICAL REVIEW A   96 ( 6 )   2017.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    We investigate how the efficiency of coherently amplified two-photon emission depends on the frequency of one of the two emitted photons, namely the signal photon. This is done over the wavelength range of 5.048-10.21 mu m by using the vibrational transition of parahydrogen. The efficiency increases with the frequency of the signal photon. Considering experimental errors, our results are consistent with the theoretical prediction for the present experimental conditions. This study is an experimental demonstration of the frequency dependence of coherently amplified two-photon emission, and also presents its potential as a light source.

    DOI: 10.1103/PhysRevA.96.063827

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    Other Link: http://orcid.org/0000-0001-8122-5145

  • A new method of creating high intensity neutron source Reviewed

    T. Masuda, A. Yoshimi, M. Yoshimura

    INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS   26 ( 11 )   2017.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WORLD SCIENTIFIC PUBL CO PTE LTD  

    We propose a new scheme of producing an intense neutron beam whose yields may exceed those of the existing facilities by a few to several orders of magnitude in the sub-eV region. This scheme employs a MeV gamma beam extracted from circulating quantum ions, which has been recently proposed. The gamma beam is directed to a deuteron target and the photo-disintegration process generates a neutron beam. The calculated neutron energy spectrum is nearly flat down to the neV range, and thus there exists a possibility to utilize a good quality of neutrons especially in sub-eV energy region without using a moderator.

    DOI: 10.1142/S0218301317500768

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    Other Link: http://orcid.org/0000-0001-8122-5145

  • Fast x-ray detector system with simultaneous measurement of timing and energy for a single photon Reviewed

    T. Masuda, S. Okubo, H. Hara, T. Hiraki, S. Kitao, Y. Miyamoto, K. Okai, R. Ozaki, N. Sasao, M. Seto, S. Uetake, A. Yamaguchi, Y. Yoda, A. Yoshimi, K. Yoshimura

    REVIEW OF SCIENTIFIC INSTRUMENTS   88 ( 6 )   2017.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER INST PHYSICS  

    We developed a fast X-ray detector system for nuclear resonant scattering (NRS) experiments. Our system employs silicon avalanche photo-diode (Si-APD) as a fast X-ray sensor. The system is able to acquire both timing and energy of a single X-ray photon simultaneously in a high rate condition, 106 counts per second for one Si-APD. The performance of the system was investigated in SPring-8, a synchrotron radiation facility in Japan. Good time resolution of 120 ps (FWHM) was achieved with a slight tail distribution in the time spectrum by a level of 10(-9) at 1 ns apart from the peak. Using this system, we successfully observed the NRS from the 26.27-keV level of mercury-201, which has a half-life of 630(50) ps. We also demonstrated the reduction of background events caused by radioactive decays in a radioactive sample by discriminating photon energy. Published by AIP Publishing.

    DOI: 10.1063/1.4989405

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    Other Link: http://orcid.org/0000-0001-8122-5145

  • Vibrational Two-Photon Emission from Coherently Excited Solid Parahydrogen Reviewed

    Yuki Miyamoto, Hideaki Hara, Takahiko Masuda, Noboru Sasao, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    JOURNAL OF PHYSICAL CHEMISTRY A   121 ( 20 )   3943 - 3951   2017.5

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    We report the observation of two-photon emission from a coherently excited vibrational state of solid parahydrogen, which is also a known quantum solid. Coherence between the ground and the excited states is prepared by stimulated Raman scattering using two visible laser pulses. The two-photon emission is triggered by another mid-infrared laser pulse. It was observed that the two-photon emission persists even when the trigger pulse is injected long after the excitation. This is due to the long decoherence time of the vibrational states of solid parahydrogen. It is found that the emission intensity increases even after the excitation pulses pass through the target completely. This coherence development is highly suppressed at high target temperatures and high residual orthohydrogen concentrations. Effects of target annealing and laser-induced damage on the target are also observed.

    DOI: 10.1021/acs.jpca.7b02011

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  • Injection-seeded tunable mid-infrared pulses generated by difference frequency mixing Reviewed

    Yuki Miyamoto, Hideaki Hara, Takahiko Masuda, Takahiro Hiraki, Noboru Sasao, Satoshi Uetake

    JAPANESE JOURNAL OF APPLIED PHYSICS   56 ( 3 )   2017.3

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    We report on the generation of nanosecond mid-infrared pulses having frequency tunability, a narrow linewidth, and a high pulse energy. These pulses are obtained by frequency mixing between injection-seeded near-infrared pulses in potassium titanyl arsenate crystals. A continuous-wave external cavity laser diode or a Ti:sapphire ring laser is used as a tunable seeding source for the near-infrared pulses. The typical energy of the generated mid-infrared pulses is in the range of 0.4-1mJ/pulse. The tuning wavelength ranges from 3142 to 4806 nm. A narrow linewidth of 1.4GHz and good frequency reproducibility of the mid-infrared pulses are confirmed by observing a rovibrational absorption line of gaseous carbon monoxide at 4587 nm. (C) 2017 The Japan Society of Applied Physics

    DOI: 10.7567/JJAP.56.032101

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  • A new search for the K-L -&gt;pi(0) nu(nu)over-barand K-L -&gt; pi X-0(0) decays Reviewed

    J. K. Ahn, K. Y. Baek, S. Banno, B. Beckford, B. Brubaker, T. Cai, M. Campbell, C. Carruth, S. H. Chen, S. Chu, J. Comfort, Y. T. Duh, T. Furukawa, H. Haraguchi, T. Hineno, Y. B. Hsiung, M. Hutcheson, T. Inagaki, M. Isoe, E. Iwai, T. Kamibayashi, I. Kamiji, N. Kawasaki, E. J. Kim, Y. J. Kim, J. W. Ko, T. K. Komatsubara, A. S. Kurilin, G. H. Lee, H. S. Lee, J. W. Lee, S. K. Lee, G. Y. Lim, C. Lin, J. Ma, Y. Maeda, T. Masuda, T. Matsumura, D. Mcfarland, J. Micallef, K. Miyazaki, K. Morgan, R. Murayama, D. Naito, K. Nakagiri, Y. Nakajima, Y. Nakaya, H. Nanjo, T. Nomura, T. Nomura, Y. Odani, R. Ogata, H. Okuno, T. Ota, Y. D. Ri, M. Sasaki, N. Sasao, K. Sato, T. Sato, S. Seki, T. Shimogawa, T. Shinkawa, S. Shinohara, K. Shiomi, J. S. Son, J. Stevens, S. Su, Y. Sugiyama, S. Suzuki, Y. Tajima, G. Takahashi, Y. Takashima, M. Tecchio, I. Teo, M. Togawa, T. Toyoda, Y. C. Tung, T. Usuki, Y. W. Wah, H. Watanabe, N. Whallon, J. K. Woo, J. Xu, M. Yamaga, S. Yamamoto, T. Yamanaka, H. Yamauchi, Y. Yanagida, H. Yokota, H. Y. Yoshida, H. Yoshimoto

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS   2017 ( 2 )   2017.2

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    DOI: 10.1093/ptep/ptx001

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  • Incident position dependence of Si-APD temporal response for a single X-ray photon at 13 . 6 keV

    High Energy Accelerator Research Organization   2017

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  • Development of a low-mass and high-efficiency charged-particle detector Reviewed

    D. Naito, Y. Maeda, N. Kawasaki, T. Masuda, H. Nanjo, T. Nomura, M. Sasaki, N. Sasao, S. Seki, K. Shiomi, Y. Tajima

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS   2016 ( 2 )   2016.2

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    We have developed a low-mass and high-efficiency charged-particle detector for an experimental study of the rare decay K-L -&gt; pi(0)nu(nu) over bar. The detector is important for suppressing the background with charged particles to the level below the signal branching ratio predicted by the Standard Model (O(10(-11))). The detector consists of two layers of 3mm thick plastic scintillators with embedded wavelength-shifting fibers and multi-pixel photon counters for the readout. We manufactured the counter and evaluated the performance in terms of light yield, timing resolution, and efficiency. With this design, we achieved an inefficiency per layer against penetrating charged particles of less than 1.5 x 10(-5), which satisfies the requirement of the KOTO experiment determined from simulation studies.

    DOI: 10.1093/ptep/ptv191

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  • Long-lived neutral-kaon flux measurement for the KOTO experiment Reviewed

    T. Masuda, J. K. Ahn, S. Banno, M. Campbell, J. Comfort, Y. T. Duh, T. Hineno, Y. B. Hsiung, T. Inagaki, E. Iwai, N. Kawasaki, E. J. Kim, Y. J. Kim, J. W. Ko, T. K. Komatsubara, A. S. Kurilin, G. H. Lee, J. W. Lee, S. K. Lee, G. Y. Lim, J. Ma, D. MacFarland, Y. Maeda, T. Matsumura, R. Murayama, D. Naito, Y. Nakaya, H. Nanjo, T. Nomura, Y. Odani, H. Okuno, Y. D. Ri, N. Sasao, K. Sato, T. Sato, S. Seki, T. Shimogawa, T. Shinkawa, K. Shiomi, J. S. Son, Y. Sugiyama, S. Suzuki, Y. Tajima, G. Takahashi, Y. Takashima, M. Tecchio, M. Togawa, T. Toyoda, Y. C. Tung, Y. W. Wah, H. Watanabe, J. K. Woo, J. Xu, T. Yamanaka, Y. Yanagida, H. Y. Yoshida, H. Yoshimoto

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS   2016 ( 1 )   2016.1

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    The KOTO(K-0 at Tokai) experiment aims to observe the CP-violating rare decay K-L -&gt; pi(0) nu(nu) over bar by using a long-lived neutral-kaon beam produced by the 30 GeV proton beam at the Japan Proton Accelerator Research Complex. The K-L flux is an essential parameter for the measurement of the branching fraction. Three K-L neutral decay modes, K-L -&gt; 3 pi(0), K-L -&gt; 2 pi(0), and K-L -&gt; 2 gamma, were used to measure the K-L flux in the beam line in the 2013 KOTO engineering run. A Monte Carlo simulation was used to estimate the detector acceptance for these decays. Agreement was found between the simulation model and the experimental data, and the remaining systematic uncertainty was estimated at the 1.4% level. The K-L flux was measured as (4.183 +/- 0.017(stat.) +/- 0.059(sys.)) x 10(7) K-L per 2 x 10(14) protons on a 66-mm-long Au target.

    DOI: 10.1093/ptep/ptv171

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  • Recent progress of SPAN towards neutrino mass spectroscopy Reviewed

    T. Masuda, H. Hara, Y. Miyamoto, N. Sasao, M. Tanaka, S. Uetake, A. Yoshimi, K. Yoshimura, M. Yoshimura

    XIV INTERNATIONAL CONFERENCE ON TOPICS IN ASTROPARTICLE AND UNDERGROUND PHYSICS (TAUP 2015), PTS 1-7   718 ( 6 )   2016

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    SPAN (SPectroscopy of Atomic Neutrino) project aims to determine the absolute neutrino mass. The process we plan to use is a cooperative de-excitation of atoms in a metastable level emitting a neutrino pair associated with a photon. The photon energy spectrum of this process contains information on the absolute mass of neutrino. Key items of this experiment are a rate amplification using macro-coherence in a target medium in case of plural particles emission and an external triggering of the emission in order to scan the spectrum. We have demonstrated the rate amplification in two-photon emission from para-hydrogen gas which was coherently excited to its first vibrationally excited state. The coherence in the medium was generated by irradiating two driving laser pulses. The emission was stimulated by irradiating a mid-infrared laser pulse. The enhancement factor of more than 10(18) with respect to the spontaneous emission was achieved. This paper briefly summarizes the results.

    DOI: 10.1088/1742-6596/718/6/062043

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  • Observation of vibrational coherent two-photon emission in solid parahydrogen

    Miyamoto Yuki, Hara Hideaki, Masuda Takahiko, Uetake Satoshi, Sasao Noboru, Yoshimi Akihiro, Yoshimura Koji, Yoshimura Motohiko

    Meeting Abstracts of the Physical Society of Japan   71   577 - 577   2016

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    DOI: 10.11316/jpsgaiyo.71.2.0_577

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  • Frequency stabilization of a transfer cavity by high-speed digital control using an FPGA

    Okai Koichi, Hara Hideaki, Masuda Takahiko, Miyamoto Yuki, Sasao Noboru, Uetake Satoshi

    Meeting Abstracts of the Physical Society of Japan   71   528 - 528   2016

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    DOI: 10.11316/jpsgaiyo.71.2.0_528

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  • Rate amplification of the two photon emission from para-hydrogen toward the neutrino mass measurement Reviewed

    Takahiko Masuda, Hideaki Hara, Yuki Miyamoto, Susumu Kuma, Itsuo Nakano, Chiaki Ohae, Noboru Sasao, Minoru Tanaka, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    HYPERFINE INTERACTIONS   236 ( 1-3 )   73 - 77   2015.11

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    We recently reported an experiment which focused on demonstrating the macro-coherent amplification mechanism. This mechanism, which was proposed for neutrino mass measurements, indicates that a multi-particle emission rate should be amplified by coherence in a suitable medium. Using a para-hydrogen molecule gas target and the adiabatic Raman excitation method, we observed that the two photon emission rate was amplified by a factor of more than 10(15) from the spontaneous emission rate. This paper briefly summarizes the previous experimental result and presents the current status and the future prospect.

    DOI: 10.1007/s10751-015-1177-1

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  • Photon-veto counters at the outer edge of the endcap calorimeter for the KOTO experiment Reviewed

    T. Matsumura, T. Shinkawa, H. Yokota, E. Iwai, T. K. Komatsubara, J. W. Lee, G. Y. Lim, J. Ma, T. Masuda, H. Nanjo, T. Nomura, Y. Odani, Y. D. Ri, K. Shiomi, Y. Sugiyama, S. Suzuki, M. Togawa, Y. Wah, H. Watanabe, T. Yamanaka

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   795   19 - 31   2015.9

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    The Outer-Edge Veto (OEV) counter subsystem for extra-photon detection from the backgrounds for the K-L(0) -&gt; pi(0) nu(nu) over bar decay is located at the outer edge of the endcap Csl calorimeter of the KOTO experiment at JPARC. The subsystem is composed of 44 counters with different cross-sectional shapes. All counters are made of lead and scintillator plates and read out through wavelength-shifting fibers. In this paper, we discuss the design and performances of the OEV counters under heavy load (similar to 8 tons/m(2) in vacuum. For 1-MeV energy deposit, the average light yield and time resolution are 20.9 photo-electrons and 1.5 ns, respectively. Although no pronounced peak by minimum-ionizing particles is observed in the energy distributions, an energy calibration method with cosmic rays works well in monitoring the gain stability with an accuracy of a few percent. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nima.2015.05.036

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  • Externally triggered coherent two-photon emission from hydrogen molecules Reviewed

    Yuki Miyamoto, Hideaki Hara, Takahiko Masuda, Noboru Sasao, Minoru Tanaka, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS   2015 ( 8 )   2015.8

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    We report on coherent enhancement of two-photon emission from the excited vibrational state of molecular hydrogen triggered by irradiating mid-infrared pulses externally. We previously observed the two-photon emission triggered by the internally generated fourth Stokes photons. By injecting independent mid-infrared pulses externally, it is possible to control the experimental parameters and investigate the mechanism in more detail. In this article, we describe the two-photon emission using the external trigger pulses. Its spectrum and dependence on the energy and timing of the trigger pulse are presented along with numerical simulations based on the Maxwell-Bloch equations. The measured number of emitted photons is 6 x 10(11) photons/pulse and the resulting enhancement factor from the spontaneous emission is more than 10(18). This value is three orders of magnitude higher than that of the previous experiment. External control of the emission process is expected to be essential for observation of the weaker process of radiative emission of a neutrino pair.

    DOI: 10.1093/ptep/ptv103

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  • Performance study of a prototype pure Csl calorimeter for the KOTO experiment Reviewed

    E. Iwai, J. W. Lee, T. Masuda, D. McFarland, Y. Nakaya, Y. D. Ri, K. Sato, K. Shiomi, Y. Sugiyama, Y. Tajima, M. Tecchio, M. Togawa, Y. C. Tung, T. Yamanaka

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   786   135 - 141   2015.6

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    The performance of the Csl electromagnetic calorimeter to be used for the J-PARC E14 KOTO experiment for a rare decay K-L --&gt; pi(0)nu(nu) over bar was studied by using a positron beam from an accelerator. The energy, timing, and position resolutions for energies up to 800 NieV were measured. We also developed a new method to reconstruct the incident angle of photons based on the shower shape recorded with the calorimeter, and evaluated the method to suppress possible backgrounds for K-L --&gt; pi(0)nu(nu) over bar decay signals. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nima.2015.02.046

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  • An aerogel Cherenkov detector for multi-GeV photon detection with low sensitivity to neutrons Reviewed

    Y. Maeda, N. Kawasaki, T. Masuda, H. Morii, D. Naito, Y. Nakajima, H. Nanjo, T. Nomura, N. Sasao, S. Seki, K. Shiomi, T. Sumida, Y. Tajima

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS   2015 ( 6 )   2015.6

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    We describe a novel multi-GeV photon detector which operates under an intense flux of neutrons. It is composed of lead-aerogel sandwich counter modules. Its salient features are high photon detection efficiency and blindness to neutrons. Monte Carlo (MC) simulations show that the efficiency for photons with energy larger than 1 GeV is expected to be higher than 99.5% and that for 2 GeV/c neutrons is less than 1%. Performance of photon detection with an underlying large flux of neutrons was measured by a partial detector with 12 modules. We confirm the efficiency for photons with energy &gt; 1 GeV is consistent with the MC expectation within an uncertainty of 8.2%.

    DOI: 10.1093/ptep/ptv074

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  • 22aDF-11 Detailed study on the macro-coherent amplification mechanism for the SPAN (SPectroscopy with Atomic Neutrino) experiment II

    Hara Hideaki, Masuda Takahiko, Miyamoto Yuki, Nakano Itsuo, Sasao Noboru, Tanaka Minoru, Uetake Satoshi, Yoshimi Akihiro, Yoshimura Koji, Yoshimura Motohiko

    Meeting Abstracts of the Physical Society of Japan   70   86 - 86   2015

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    DOI: 10.11316/jpsgaiyo.70.1.0_86

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  • 22pAG-7 Coherent two-photon emission from the vibrational excited states of hydrogen molecules III

    Uetake Satoshi, Hara Hideaki, Masuda Takahiko, Miyamoto Yuki, Nakano Itsuo, Sasao Noboru, Tanaka Minoru, Yoshimi Akihiro, Yoshimura Koji, Yoshimura Motohiko

    Meeting Abstracts of the Physical Society of Japan   70   668 - 668   2015

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    DOI: 10.11316/jpsgaiyo.70.1.0_668

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  • Observation of coherent two-photon emission from the first vibrationally excited state of hydrogen molecules Reviewed

    Yuki Miyamoto, Hideaki Hara, Susumu Kuma, Takahiko Masuda, Itsuo Nakano, Chiaki Ohae, Noboru Sasao, Minoru Tanaka, Satoshi Uetake, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS   2014 ( 11 )   2014.11

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    In this paper, we describe an experiment which was conducted to explore the macro-coherent amplification mechanism using a two-photon emission process from the first vibrationally excited state of the para-hydrogen molecule. Large coherence in the initial state was prepared by the adiabatic Raman method, and the lowest Stokes sideband was used as a trigger field. We observed coherent two-photon emission consistent with the expectation of the Maxwell-Bloch equation derived for the process, whose rate is larger by many orders of magnitude than that of spontaneous emission.

    DOI: 10.1093/ptep/ptu152

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  • A vacuum tolerant high voltage system with a low noise and low power Cockcroft-Walton photomultiplier base Reviewed

    T. Masuda, E. Iwai, N. Kawasaki, E. J. Kim, T. K. Komatsubara, J. W. Lee, G. Y. Lim, Y. Maeda, D. Naito, H. Nanjo, T. Nomura, Y. D. Ri, N. Sasao, K. Sato, S. Seki, K. Shiomi, Y. Sugiyama, M. Togawa, H. Watanabe, T. Yamanaka

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   746   11 - 19   2014.5

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    We developed a high voltage system for the electromagnetic calorimeter of the KOTO detector. The system is designed around a low noise, low power Cockcroft-Walton (CW) photomultiplier tube base with a high gain preamplifier. The low power makes it suitable for operations in vacuum. The low noise and high gain allow detecting signals in the 1 MeV range. We achieved a final noise level below 180 mu Vrms, for a preamplifier gain of more than 40. A vacuum tolerant control system for the CW bases power distribution was also designed. This system is able to control and monitor the high voltage of each individual base. (c) 2014 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nima.2014.02.007

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  • Measurement of K-L(0) flux at the J-PARC neutral-kaon beam line Reviewed

    K. Shiomi, K. Y. Baek, J. Comfort, E. Iwai, N. Kawasaki, J. W. Ko, T. K. Komatsubara, J. W. Lee, G. Y. Lim, Y. Maeda, T. Masuda, D. Naito, Y. Nakaya, H. Nanjo, T. Nomura, M. Sasaki, N. Sasao, K. Sato, T. Shimogawa, Y. Sugiyama, Y. Tajima, G. Takahashi, M. Togawa, H. Watanabe, T. Yamanaka, Y. Yanagida, H. Y. Yoshida

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   664 ( 1 )   264 - 271   2012.2

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    We describe the K-L(0) flux measurements performed at the J-PARC neutral-kaon beam line. This beam line was constructed for an experiment aiming to observe the CP-violating rare decay K-L(0) -&gt; pi(0)nu(nu) over bar The primary proton energy was 30 GeV and the K-L(0) production angle was 16 degrees. Prior to the physics run, the flux and spectrum were measured by counting K-L(0) -&gt; pi(+)pi(-)pi(0) decays with a simple setup, which was composed of an electromagnetic calorimeter and a hodoscope system. Results from these measurements are presented and compared with various hadron-interaction simulations. (C) 2011 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.nima.2011.11.010

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  • Development of a Neutral Beam Profile Monitor Reviewed

    Goh Takahashi, Kwang Yun Baek, Naoki Kawasaki, Takeshi K. Komatsubara, Gei-Youb Lim, Yosuke Maeda, Takahiko Masuda, Hideki Morii, Daichi Naito, Hajime Nanjo, Tadashi Nomura, Noboru Sasao, Kazufumi Sato, Tetsushi Shimogawa, Kouji Shiomi, Yasuhisa Tajima, Hiroaki Watanabe, Taku Yamanaka

    JAPANESE JOURNAL OF APPLIED PHYSICS   50 ( 3 )   2011.3

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    We developed a novel beam profile monitor for measuring the shape of an intense neutral beam for particle physics. This monitor is based on a detector technology of scintillating fibers, photomultiplier tubes, and sampling ADCs. It has an advantage for its simplicity, reliability, flexibility, and versatility. This monitor was installed in the small-diameter neutral beam for the K-L(0) -> pi(0)nu(nu) over bar experiment at J-PARC. We report in this article the development and performance of this monitor. (C) 2011 The Japan Society of Applied Physics

    DOI: 10.1143/JJAP.50.036701

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Presentations

  • Silicon photomultiplier embedded photodetector for ACME III International coauthorship International conference

    T. Masuda, D.G. Ang, D. DeMille, C. Diver, J.M. Doyle, G. Gabrielse, Z. Han, A. Hiramoto, P. Hu, N.R. Hutzler, D. Lascar, Z. Lasner, S. Liu, C. Meisenhelder, J. Mitchell, C.D. Panda, N. Sasao, S. Uetake, M. Watts, X. Wu, K. Yoshimura

    The 27th International Conference on Atomic Physics  2022.7.18 

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    Event date: 2022.7.17 - 2022.7.22

    Language:English   Presentation type:Poster presentation  

    Venue:Tronto  

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  • トリウム原子核アイソマー安定生成のための X線ビームエネルギー測定システムの詳細 Invited

    増田孝彦

    第15回核共鳴散乱研究会  2022.3.7  SPRUC

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    Event date: 2022.3.7

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:Spring-8  

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  • 電子EDM Invited

    増田孝彦

    S型課題研究会  2021.12.17 

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    Event date: 2021.12.16 - 2021.12.17

    Language:Japanese  

    Venue:名古屋大学、オンライン併用  

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  • 冷却原子・分子で探るバリオジェネシス International coauthorship

    増田孝彦

    日本物理学会2021年秋季大会  2021.9.16  日本物理学会

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    Event date: 2021.9.14 - 2021.9.17

    Language:Japanese   Presentation type:Symposium, workshop panel (public)  

    Venue:オンライン  

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  • Silicon photomultiplier module as a photon detector for ACME III Electron EDM search International coauthorship International conference

    Takahiko Masuda, Daniel G. Ang, David DeMille, John M. Doyle, Gerald Gabrielse, Zhen Han, Bingjie Hao, Ayami Hiramoto, Peiran Hu, Nicholas Hutzler, Daniel Lascar, Siyuan Liu, Cole Meisenhelder, Cristian Panda, Noboru Sasao, Satoshi Uetake, Xing Wu, Koji Yoshimura

    The 52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics  2021.6.3  American Physical Society

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    Event date: 2021.5.31 - 2021.6.4

    Language:English   Presentation type:Poster presentation  

    Venue:online  

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  • トリウム229原子核における アイソマー準位のX線ポンピング Invited

    増田孝彦

    日本物理学会 第76回年次大会  2021.3.13  日本物理学会

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    Event date: 2021.3.12 - 2021.3.15

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:online  

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  • Upgrade towards the next electron electric dipole moment search International coauthorship

    T. Masuda, D. Ang, J. Chow, D. DeMille, J. Doyle, G. Gabrielse, Z. Han, B. Hao, P. Hu, N. Hutzler, D. Lascar, S. Liu, C. Meisenhelder, C. Panda, N. Sasao, S. Uetake, X. Wu, K. Yoshimura

    日本物理学会2020年秋季大会  2020.9.16  日本物理学会

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    Event date: 2020.9.14 - 2020.9.17

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:オンライン  

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  • Development of a silicon photomultiplier module for ACME III International coauthorship International conference

    Takahiko Masuda, Daniel Ang, James Chow, David DeMille, John Doyle, Gerald Gabrielse, Zhen Han, Bingjie Hao, Peiran Hu, Nicholas Hutzler, Daniel Lascar, Siyuan Liu, Cole Meisenhelder, Cristian Panda, Noboru Sasao, Satoshi Uetake, Xing Wu, Koji Yoshimura

    DAMOP 2020: The 51st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics  2020.6.3  American Physical Society

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    Event date: 2020.6.1 - 2020.6.5

    Language:English   Presentation type:Poster presentation  

    Venue:Virtual  

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  • トリウム229原子核異性体からの真空紫外光分光に向けた取り組み Invited

    増田孝彦

    第3回若手放談会:エキゾチック核物理の将来  2020.2.20  理研 RIBF 理論研究推進会議、理研仁科センター RIBF 研究部門

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    Event date: 2020.2.19 - 2020.2.21

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:理化学研究所神戸キャンパス  

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  • Active pumping of the isomeric state of 229Th nucleus towards a nuclear clock International conference

    Takahiko Masuda

    Cosmic acceleration conference  2020.2.17 

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    Event date: 2020.2.17 - 2020.2.19

    Language:English   Presentation type:Poster presentation  

    Venue:Kashiwa Campus, The university of Tokyo  

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  • Electron electric dipole moment search by using cold molecules Invited

    Takahiko MASUDA

    Iwasaki laboratory seminar  2022.1.28 

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    Venue:online (RIKEN)  

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  • X-ray pumping of the 229Th nuclear clock isomer Invited

    Masuda Takahiko

    The CFP Colloquium  2019.12.3  The Center for Fundamental Physics, Northwestern University

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    Venue:Northwestern University  

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  • トリウム229原子核異性体からの真空紫外光観測の現状

    増田孝彦

    日本物理学会 2019年秋季大会  2019.9.19  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:山形大学  

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  • ミューオニウム精密分光によるミューオン質量の高精度決定と新物理探索の可能性

    増田孝彦

    日本物理学会 第74回年次大会  2019.3.15  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:九州大学伊都キャンパス  

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  • Realization of the active pumping of thorium-229 isomeric state International conference

    Masuda Takahiko

    “Cosmic acceleration” symposium  2019.3.3 

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  • X-ray pumping of the nuclear-clock isomer 229Th Invited International conference

    Masuda Takahiko

    The 11th international workshop on Fundamental Physics Using Atoms 2019  2019.3.1 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Fast APD detector with a short tail in the timing response for an experiment using synchrotron radiation X-ray beam International conference

    Masuda Takahiko

    5th International Workshop on New Photon-Detectors  2018.11.27 

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    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo University, Tokyo, JAPAN  

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  • Search for the ultra-low energy isomer state of thorium-229 nuclei International conference

    Masuda Takahiko

    5th Joint Meeting of the Division of Nuclear Physics of the APS and the JPS  2018.10.23 

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  • トリウム229原子核の極低エネルギー励起状態探索実験

    増田孝彦

    日本物理学会 第73回年次大会  2018.3.25  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京理科大学野田キャンパス  

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  • Si-APD array detector for a single X-ray photon detection with high timing resolution, energy resolution, and high rate capability International conference

    Masuda Takahiko

    2017 IEEE Nuclear Science Symposium and Medical Imaging Conference / 24th Symposium on Room-Temperature X- and Gamma-Ray Detectors  2017.10.26  IEEE

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    Language:English   Presentation type:Oral presentation (general)  

    Venue:Atlanta, U.S.A.  

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  • Si-APDを用いたX線用高繰返し・高時間分解能検出器システムの開発

    増田孝彦

    日本物理学会 第72回年次大会  2017.3.17  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪大学豊中キャンパス  

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  • Study on amplified multi-photon emission processes from macroscopically coherent media Invited International conference

    Masuda Takahiko

    The 9th international workshop on Fundamental Physics Using Atoms  2017.1.10 

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    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Kyoto University, Kyoto, Japan  

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  • SPAN実験(原子を用いたニュートリノ質量分光)のための、多光子放出実験の進展

    増田孝彦

    日本物理学会 2016年秋期大会  2016.9.21  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:宮崎大学木花キャンパス  

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  • A search for the low-energy 229Th nuclear isomeric transition using nuclear resonant scattering International conference

    Masuda Takahiko

    25th International Conference on Atomic Physics  2016.7.28 

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    Language:English   Presentation type:Poster presentation  

    Venue:Seoul, KOREA  

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  • SPAN実験(ニュートリノ質量分光実験)のための対向励起実験の進行状況

    増田孝彦

    日本物理学会 第71回年次大会  2016.3.21  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東北学院大学泉キャンパス  

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  • Recent progress of SPAN towards neutrino mass spectroscopy International conference

    Masuda Takahiko

    14th International Conference on Topics in Astroparticle and Underground Physics  2015.9.9 

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    Language:English   Presentation type:Oral presentation (general)  

    Venue:Trin, Italy  

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  • SPAN(原子を用いたニュートリノ質量分光実験)のためのマクロコヒーレンス増幅機構の詳細研究I

    増田孝彦

    日本物理学会 第70回年次大会  2015.3.22  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:早稲田大学早稲田キャンパス  

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  • ニュートリノ質量分光に向けた、コヒーレンスによる二光子対超放射の観測

    増田孝彦

    21st ICEPP Symposium  2015.2.10 

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:長野県 北安曇郡 白馬村 岳美山荘  

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  • Rate amplification of the two photon emission from para-hydrogen toward the neutrino mass measurement International conference

    Masuda Takahiko

    The sixth international conference on Trapped Charged Particle and Fundamental Physics (TCP2014)  2014.12.2 

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    Language:English   Presentation type:Poster presentation  

    Venue:Takamatsu, JAPAN  

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  • ニュートリノ質量分光に向けた マクロコヒーレンス生成方法の実証

    増田孝彦

    日本物理学会2014年秋季大会  2014.9.19  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:佐賀大学本庄キャンパス  

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  • Neutrino Spectroscopy with Atoms and Molecules International conference

    Masuda Takahiko

    24th International Conference on Atomic Physics  2014.8 

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    Venue:Washignton DC  

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  • J-PARC KOTO実験 エンジニアリングランによる解析方法の確立

    増田孝彦

    日本物理学会第69回年次大会  2014.3.27  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東海大学  

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  • KOTO実験(J-PARC KL→π0νν̅ 崩壊探索実験)と その初期性能評価 Invited

    増田孝彦

    量子宇宙研究センター・極限量子研究コア合同セミナー  2013.11.27  量子宇宙研究センター・極限量子研究コア

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    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:岡山大学  

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  • J-PARC KOTO実験のためのKL beam 評価

    増田孝彦

    日本物理学会2013年秋季大会  2013.10.21  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:高知大学  

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  • KOTO detector status Invited International conference

    Masuda Takahiko

    2013 KAON international conference (KAON13)  2013.5 

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    Venue:University of Michigan, Ann Arbor, Illinois, U.S.A.  

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  • KOTO実験エンジニアリングラン解析

    増田孝彦

    日本物理学会第68回年次大会  2013.3.26  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:広島大学  

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  • Status of the engineering run of the KOTO experiment International conference

    Masuda Takahiko

    GCOE Symposium  2013.2 

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    Language:English   Presentation type:Poster presentation  

    Venue:Kyoto University, Kyoto, Japan  

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  • KOTO実験 CsI電磁カロリメータにおけるPMT放電による影響と対策

    増田孝彦

    日本物理学会2012年秋季大会  2012.9.12  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都産業大学  

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  • The CsI calorimeter system for the KOTO experiment International conference

    Masuda Takahiko

    GCOE Symposium  2012.2 

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    Venue:Kyoto University, Kyoto, Japan  

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  • KOTO実験における学生とエレクトロニクス

    増田孝彦

    計測システム開発検討会  2011.11 

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    Venue:京都大学  

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  • KOTO実験におけるCharged Vetoのコントロールシステム

    増田孝彦

    日本物理学会2011年秋季大会  2011.9.18  日本物理学会

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    Venue:弘前大学  

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  • KOTO実験のCsIカロリメータの時間性能の評価

    増田孝彦

    日本物理学会2011年秋季大会  2011.9.16  日本物理学会

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    Venue:弘前大学  

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  • KOTO実験に用いる低消費電力型PMTベースの大量生産報告と、そのコントロールについて

    増田孝彦

    日本物理学会2010年秋季大会  2010.9.13  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:九州工業大学  

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  • KOTO実験(J-PARC KL→π0νν探索実験)に用いるプリアンプ内蔵低消費電力型PMTの開発

    増田孝彦

    日本物理学会第65回年次大会  2010.3.20  日本物理学会

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    Venue:岡山大学  

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  • Low power PMT base for KOTO experiment using Cockcroft-Walton circuit International conference

    Masuda Takahiko

    GCOE Symposium  2010.2 

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  • KOTO実験(J-PARC KL→π0νν探索実験)に用いるプリアンプ内蔵低消費電力型PMTの開発

    増田孝彦

    日本物理学会2009年秋季大会  2009.9.10  日本物理学会

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    Venue:甲南大学  

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  • Low power PMT base for KOTO experiment using Cockcroft-Walton circuit International conference

    Masuda Takahiko

    XXIX international conference on Physics in Collision (PIC09)  2009.8 

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    Venue:Kobe University, Kobe, Japan  

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  • CsI Calorimeter and low power PMT base for KOTO experiment International conference

    Masuda Takahiko

    2009 KAON international conference (KAON09)  2009.6 

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    Language:English   Presentation type:Poster presentation  

    Venue:EPOCAL, Tsukuba, Ibaraki  

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  • KOTO実験(J-PARC KL→π0νν探索実験)用PMTプロトタイプの性能評価とボルテージコントロールについて

    増田孝彦

    日本物理学会第64回年次大会  2009.3.30  日本物理学会

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    Venue:立教大学  

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  • CsI Calorimeter system for KOTO experiment International conference

    Masuda Takahiko

    The 1st international conference on Technology and Instrumentation in Particle Physics 2009 (TIPP09)  2009.3 

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    Venue:EPOCAL, Tsukuba, Ibaraki  

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  • KOTO実験のためのCsI Calorimeter 用PMT baseの開発とコントロールシステム

    増田孝彦

    15th ICEPP symposium  2009.2  ICEPP

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    Venue:長野県 北安曇郡 白馬村 岳美山荘  

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  • KOTO実験(J-PARC KL→π0νν探索実験)におけるCsIカロリメータへの要請と読み出しPMTの開発

    増田孝彦

    日本物理学会2008年秋季大会  2008.9.21  日本物理学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:山形大学  

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  • KL→π0νν探索実験(E14)のためのCsIカロリメータ読み出しPMT baseの開発

    増田孝彦

    日本物理学会第63回年次大会  2008.3.23  日本物理学会

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    Venue:近畿大学  

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  • KL→π0νν探索実験(E14)のためのCsIカロリメータ読み出しフロントエンド回路の開発

    増田孝彦

    日本物理学会第62回年次大会  2007.9.21  日本物理学会

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    Venue:北海道大学  

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Awards

Research Projects

  • 高感度光検出による、分子内電子の永久電気双極子能率測定の高度化

    2021.11

    公益財団法人 松尾学術振興財団  第34回松尾学術研究助成 

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    Authorship:Principal investigator 

    Grant amount:\2200000 ( Direct expense: \2200000 )

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  • ミューオン-電子束縛系のレーザー励起に向けた高精度ミューオン検出法の開拓

    2020.11

    公益財団法人住友財団  基礎科学研究助成 

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    Authorship:Principal investigator 

    Grant amount:\1500000 ( Direct expense: \1500000 )

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  • 冷却極性分子の量子操作による電子の永久電気双極子モーメント探索 International coauthorship

    Grant number:20KK0068  2020.10 - 2026.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))  Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

    増田 孝彦

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\18720000 ( Direct expense: \14400000 、 Indirect expense:\4320000 )

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  • 能動的核異性体生成法で迫る、トリウム229原子核異性体の高精度レーザー分光 International coauthorship

    Grant number:19H00685  2019.04 - 2023.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)  Grant-in-Aid for Scientific Research (A)

    増田 孝彦, 北尾 真司, 山口 敦史

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\45110000 ( Direct expense: \34700000 、 Indirect expense:\10410000 )

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  • 核共鳴散乱法を用いた原子核からの紫外線発光検出 International coauthorship

    2019.04 - 2020.03

    公益財団法人稲盛財団  稲盛研究助成 

    増田孝彦

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\1000000

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  • 物理定数恒常性測定の飛躍的精度向上に向けた、原子核のレーザー励起の実現

    Grant number:18H04353  2018.04 - 2020.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    増田 孝彦

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    Authorship:Principal investigator 

    Grant amount:\10400000 ( Direct expense: \8000000 、 Indirect expense:\2400000 )

    加速宇宙の謎に関わる可能性のある微細構造定数恒常性の測定感度を大幅に改善すると期待されるのがトリウム229原子核の極低エネルギー核異性体準位である。本年度は放射光X線核共鳴散乱法を用いたトリウム229の原子核第二励起準位への励起に成功し、これによって極低エネルギー核異性体を能動的に生成できるようになった。また測定データを詳細に解析することで、原子核第二励起準位に関わる各種パラメータ(寿命、エネルギー幅、崩壊分岐比など)を決定した。
    入射X線のエネルギースキャンを実現するためには、毎秒150メガバイトに渡るデータ量を、その場解析を行いつつデッドタイムフリーで数日間取得し続けるという測定システムとデータストレージが必要であった。本研究課題で必要なストレージと解析能力を備えたシステムを構築した。
    今後の真空紫外光分光に向け重要なのが真空分光器の波長較正方法の確立である。分光器による測定結果が真の波長とずれていると正確なエネルギーが特定できない。また波長較正は現場での測定時に同時に行うことが望ましいため、混み合ったビームライン中でも較正できる小型なシステムが必要であった。炭酸ガスの直流グロー放電による一酸化炭素分子の蛍光ピークを用いることで、比較的簡易なシステムでも1ナノメートルを超える精度で較正できることを確認した。蛍光ピークは150から200ナノメートルに分布しており、この付近に信号がくれば問題なく波長較正できることが確認できた。

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  • Amplification of the counter propagating two-photon emission toward the neutrino mass spectroscopy

    Grant number:17K14292  2017.04 - 2019.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)  Grant-in-Aid for Young Scientists (B)

    Masuda Takahiko

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    Authorship:Principal investigator 

    Grant amount:\4160000 ( Direct expense: \3200000 、 Indirect expense:\960000 )

    We observed two-photon emission signal from the first vibrationally excited state of parahydrogen gas coherently excited by counter-propagating laser pulses. A single narrow-linewidth laser source has roles in the excitation of the parahydrogen molecules and the induction of the TPE process. We measured dependences of the signal energy on the detuning, target gas pressure, and input pulse energies. These results are qualitatively consistent with those obtained by numerical simulations based on Maxwell-Bloch equations with one spatial dimension and one temporal dimension. This study of the TPE process in the counter-propagating injection scheme is an important step toward neutrino mass spectroscopy.

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  • 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference

    2017.04 - 2018.03

    公益財団法人岡山工学振興会  国際研究集会派遣助成 

    増田孝彦

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\174000

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  • ニュートリノ絶対質量測定に向けた、二光子対超放射の系統的研究と制御方法開発

    2015.09 - 2016.03

    岡山大学  学内競争的資金 

    増田孝彦

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\1000000

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  • ニュートリノ質量測定のための、水素ガスからの二光子対超放射の制御方法開発

    2014.09 - 2016.03

    日本学術振興会  科学研究費補助金(研究活動スタート支援) 

    増田孝彦

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\2470000 ( Direct expense: \1900000 、 Indirect expense:\570000 )

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  • 中性K中間子のCP非保存稀崩壊の測定実験による新物理モデルの探索

    2010.04 - 2013.03

    日本学術振興会  科学研究費補助金(特別研究員奨励費) 

    増田孝彦

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\2100000 ( Direct expense: \2100000 )

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Social Activities

  • 光と素粒子 〜レーザーや素粒子を自分で測ってみよう〜

    Role(s):Lecturer, Planner

    日本学術振興会  ひらめき☆ときめきサイエンス  岡山大学  2017.8.11

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    Audience: High school students

    Type:Science cafe

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  • 光と素粒子 〜レーザーや素粒子を自分で測ってみよう〜

    Role(s):Lecturer, Planner

    日本学術振興会  ひらめき☆ときめきサイエンス  岡山大学  2016.8.11

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    Audience: High school students

    Type:Science cafe

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  • 消えた反物質の謎

    Role(s):Lecturer

    Ecole de Touzan  京都ハイアットリージェンシーホテル  2013.7.20

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    Audience: General

    Type:Science cafe

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  • 宇宙の謎、消えた反物質

    Role(s):Lecturer

    京都大学宇宙総合学研究ユニット  全国同時七夕講演会2011  京都大学  2011.7.8

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    Audience: General

    Type:Science cafe

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Academic Activities

  • 日本物理学会2022年秋季大会

    Role(s):Planning, management, etc.

    日本物理学会  2022.9.6 - 2022.9.8

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    Type:Competition, symposium, etc. 

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  • The 12th international workshop on Fundamental Physics using Atoms 2020

    Role(s):Panel moderator, session chair, etc.

    2020.1.9 - 2020.1.10

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    Type:Academic society, research group, etc. 

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  • International workshop on "Axion physics and dark matter cosmology"

    Role(s):Planning, management, etc.

    2017.12.20 - 2017.12.21

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    Type:Academic society, research group, etc. 

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