研究者詳細 - 吉見　彰洋

論文 - 吉見　彰洋

分割表示 148 件中 1 - 20 件目／全件表示 >>

A method to detect the VUV photons from cooled 229Th:CaF<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si16.svg" display="inline" id="d1e109"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> crystals

Ming Guan, Michael Bartokos, Kjeld Beeks, Yuta Fukunaga, Takahiro Hiraki, Takahiko Masuda, Yuki Miyamoto, Ryoichiro Ogake, Koichi Okai, Noboru Sasao, Fabian Schaden, Thorsten Schumm, Kotaro Shimizu, Sayuri Takatori, Akihiro Yoshimi, Koji Yoshimura

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 562 165647 - 165647 2025年5月

Characterization of the thorium-229 defect structure in CaF₂ crystals

Sayuri Takatori, Martin Pimon, Stephan Pollitt, Michael Bartokos, Kjeld Beeks, Andreas Grüneis, Takahiro Hiraki, Tetsuo Honma, Niyusha Hosseini, Adrian Leitner, Takahiko Masuda, Ira Morawetz, Kiyofumi Nitta, Koichi Okai, Thomas Riebner, Fabian Schaden, Thorsten Schumm, Oki Sekizawa, Tomas Sikorsky, Yoshio Takahashi, Luca Toscani De Col, Rei Yamamoto, Takumi Yomogida, Akihiro Yoshimi, Koji Yoshimura

New Journal of Physics 2025年4月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

Recent advancements in laser excitation of the low-energy thorium-229 (²²⁹Th) nuclear isomeric state in calcium fluoride (CaF₂) single crystals render this system a promising candidate for a solid-state nuclear clock. Nonetheless, the precise experimental determination of the microscopic ion configuration surrounding the doped ²²⁹Th and its electronic charge state remains a critical challenge. Such characterization is essential for accurately controlling the clock transition and evaluating the performance of this solid-state nuclear clock system. In this study, we use x-ray absorption fine structure spectroscopy of ²²⁹Th:CaF₂ to investigate the charge state and coordination environment of doped ²²⁹Th. The results indicate that ²²⁹Th displays a 4+ oxidation state at the substitutional site of a Ca²⁺ ion, with charge compensated provided by two F^- ions positioned at interstitial sites adjacent to ²²⁹Th.

DOI： 10.1088/1367-2630/adce22

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その他リンク： https://iopscience.iop.org/article/10.1088/1367-2630/adce22/pdf

Controlling 229Th isomeric state population in a VUV transparent crystal

Takahiro Hiraki, Koichi Okai, Michael Bartokos, Kjeld Beeks, Hiroyuki Fujimoto, Yuta Fukunaga, Hiromitsu Haba, Yoshitaka Kasamatsu, Shinji Kitao, Adrian Leitner, Takahiko Masuda, Ming Guan, Nobumoto Nagasawa, Ryoichiro Ogake, Martin Pimon, Martin Pressler, Noboru Sasao, Fabian Schaden, Thorsten Schumm, Makoto Seto, Yudai Shigekawa, Kotaro Shimizu, Tomas Sikorsky, Kenji Tamasaku, Sayuri Takatori, Tsukasa Watanabe, Atsushi Yamaguchi, Yoshitaka Yoda, Akihiro Yoshimi, Koji Yoshimura

Nature Communications 15 ( 1 ) 2024年7月

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

Abstract

The radioisotope thorium-229 (²²⁹Th) is renowned for its extraordinarily low-energy, long-lived nuclear first-excited state. This isomeric state can be excited by vacuum ultraviolet (VUV) lasers and ²²⁹Th has been proposed as a reference transition for ultra-precise nuclear clocks. To assess the feasibility and performance of the nuclear clock concept, time-controlled excitation and depopulation of the ²²⁹Th isomer are imperative. Here we report the population of the ²²⁹Th isomeric state through resonant X-ray pumping and detection of the radiative decay in a VUV transparent ²²⁹Th-doped CaF₂ crystal. The decay half-life is measured to 447(25) s, with a transition wavelength of 148.18(42) nm and a radiative decay fraction consistent with unity. Furthermore, we report a new “X-ray quenching” effect which allows to de-populate the isomer on demand and effectively reduce the half-life. Such controlled quenching can be used to significantly speed up the interrogation cycle in future nuclear clock schemes.

DOI： 10.1038/s41467-024-49631-0

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その他リンク： https://www.nature.com/articles/s41467-024-49631-0

Experimental apparatus for detection of radiative decay of $$^{229}$$Th isomer from Th-doped CaF$$_2$$

Takahiro Hiraki, Kjeld Beeks, Michael Bartokos, Hiroyuki Fujimoto, Yuta Fukunaga, Hiromitsu Haba, Yoshitaka Kasamatsu, Shinji Kitao, Adrian Leitner, Takahiko Masuda, Guan Ming, Nobumoto Nagasawa, Ryoichiro Ogake, Koichi Okai, Martin Pimon, Martin Pressler, Noboru Sasao, Fabian Schaden, Thorsten Schumm, Makoto Seto, Yudai Shigekawa, Koutaro Shimizu, Tomas Sikorsky, Kenji Tamasaku, Sayuri Takatori, Tsukasa Watanabe, Atsushi Yamaguchi, Yoshitaka Yoda, Akihiro Yoshimi, Koji Yoshimura

Hyperfine Interactions 245 ( 1 ) 2024年1月

Periodic superradiance in an Er:YSO crystal

Hideaki Hara, Junseok Han, Yasutaka Imai, Noboru Sasao, Akihiro Yoshimi, Koji Yoshimura, Motohiko Yoshimura, Yuki Miyamoto

Physical Review Research 2024年1月

Vacuum Tltraviolet Search from Thorium-229 Isomer in Crystal Toward Solid-State Nuclear Clock

S. Takatori, Y. Fukunaga, M. Guan, T. Hiraki, T. Masuda, R. Ogake, K. Okai, N. Sasao, K. Shimizu, S. Uetake, A. Yoshimi, K. Yoshimura, M. Yoshimura, K. Tamasaku, Y. Kasamatsu, Y. Yasuda, K. Beeks, F. Schaden, T. Schumm, S. Kitao, M. Seto, H. Fujimoto, T. Watanabe, K. Konashi, M. Watanabe, H. Haba, Y. Shigekawa, A. Yamaguchi, N. Nagasawa, Y. Yoda

2023 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS) 2023年5月

Quantum dots as a probe of fundamental physics: deviation from exponential decay law 査読

Akihiro Yoshimi, Minoru Tanaka, Motohiko Yoshimura

The European Physical Journal D 76 113 2022年7月

Parity violating magnetization at neutrino pair emission using trivalent lanthanoid ions 査読

Hideaki Hara, Akihiro Yoshimi, Motohiko Yoshimura

Physical Review D 104 ( 11 ) 2021年12月

Estimation of radiative half-life of Th229m by half-life measurement of other nuclear excited states in Th229

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 ) 2021年8月

Absolute X-ray energy measurement using a high-accuracy angle encoder

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年1月

掲載種別：研究論文（学術雑誌）出版者・発行元：International Union of Crystallography ({IUCr})

<jats:p>This paper presents an absolute X-ray photon energy measurement method that uses a Bond diffractometer. The proposed system enables the prompt and rapid <jats:italic>in situ</jats: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.</jats:p>

DOI： 10.1107/s1600577520014526

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Neutrino mass spectroscopy using Er3+ ions placed at inversion center of host crystals

H. Hara, N. Sasao, A. Yoshimi, M. Yoshimura

arXiv:1910.14318v1 2019年10月

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

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

Nucl. Instrum. Methods Phys. Res. A. 913 72 - 77 2019年

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

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

J. Physics B 52 ( 23 ) 235402 2019年

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

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

J. Phys. B 52 ( 4 ) 045401 2019年

X-ray pumping of the 229Th nuclear clock isomer 査読

T. Masuda, A. Yoshimi, A. Fujieda, H. Fujimoto, H. Haba, H. Hara, T. Hiraki, H. Kaino, Y. Kasamatsu, S. Kitao, K. Konashi, Y. Miyamoto, K. Okai, S. Okubo, N. Sasao, M. Seto, T. Schumm, Y. Shigekawa, K. Suzuki, S. Stellmer, K. Tamasaku, S. Uetake, M. Watanabe, T. Watanabe, Y. Yasuda, A. Yamaguchi, Y. Yoda, T. Yokokita, M. Yoshimura, K. Yoshimura

Nature 573 ( 7773 ) 238 - 242 2019年

Development of co-located 129Xe and 131Xe nuclear spin masers with external feedback scheme 査読

T. Sato, Y. Ichikawa, S. Kojima, C. Funayama, S. Tanaka, T. Inoue, A. Uchiyama, A. Gladkov, A. Takamine, Y. Sakamoto, Y. Ohtomo, C. Hirao, M. Chikamori, E. Hikota, T. Suzuki, M. Tsuchiya, T. Furukawa, A. Yoshimi, C. P. Bidinosti, T. Ino, H. Ueno, Y. Matsuo, T. Fukuyama, N. Yoshinaga, Y. Sakemi, K. Asahi

Physics Letters, Section A: General, Atomic and Solid State Physics 382 ( 8 ) 588 - 594 2018年2月

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 B.V.

We report on the operation of co-located 129Xe and 131Xe nuclear spin masers with an external feedback scheme, and discuss the use of 131Xe as a comagnetometer in measurements of the 129Xe spin precession frequency. By applying a correction based on the observed change in the 131Xe frequency, the frequency instability due to magnetic field and cell temperature drifts are eliminated by two orders of magnitude. The frequency precision of 6.2 μHz is obtained for a 104 s averaging time, suggesting the possibility of future improvement to ≈ 1 nHz by improving the signal-to-noise ratio of the observation.

DOI： 10.1016/j.physleta.2017.12.003

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

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 ) 024607 2018年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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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Vibrational excitation of hydrogen molecules by two-photon absorption and third-harmonic generation 査読

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 ) 015401 2018年1月

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

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

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

PHYSICAL REVIEW A 96 ( 6 ) 063827 2017年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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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A new method of creating high intensity neutron source 査読

T. Masuda, A. Yoshimi, M. Yoshimura

INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS 26 ( 11 ) 1750076 2017年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Web of Science

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