研究者詳細 - 宮本　祐樹

論文 - 宮本　祐樹

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

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

Physical Review C 97 ( 2 ) 024607 2018年

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

Vibrational Two-Photon Emission from Coherently Excited Solid Parahydrogen 査読

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

Journal of Physical Chemistry A 121 ( 20 ) 3943 - 3951 2017年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：American Chemical Society ({ACS})

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

Experimental verification of the cluster model of CH<inf>3</inf>F-(ortho-H<inf>2</inf>)<inf>n</inf> in solid para-H<inf>2</inf> by using mid-infrared pump-probe laser spectroscopy 査読

Miyamoto, Y., Mizoguchi, A., Kanamori, H.

Journal of Chemical Physics 146 ( 11 ) 2017年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

The bleaching process in the C-F stretching mode (v(3) band) of CH3F-(ortho-H-2)(n) [n = 0 and 1] clusters in solid para-H-2 was monitored using pump and probe laser spectroscopy on the C-H stretching mode (v(1) and 2v(5) bands). From an analysis of the depleted spectral profiles, the transition frequency and linewidth of each cluster were directly determined. The results agree with the values previously derived from a deconvolution analysis of the broadened v(1)/2v(5) spectrum observed by FTIR spectroscopy. The complementary increase and decrease between the n = 0 and 1 components were also verified through monitoring the v(1) and 2v(5) bands, which suggests a closed system among the CH3F(ortho-H-2)(n) clusters. These observations provide experimental verification of the CH3F-(ortho-H-2)(n) cluster model. On the other hand, a trial to observe the bleaching process by pumping the C-H stretching mode was not successful. This result may be important for understanding the dynamics of vibrational relaxation processes in CH3F-(ortho-H-2) n in solid para-H-2. Published by AIP Publishing.

DOI： 10.1063/1.4978227

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

Miyamoto, Y., Hara, H., Masuda, T., Hiraki, T., Sasao, N., Uetake, S.

Japanese Journal of Applied Physics 56 ( 3 ) 2017年

担当区分：筆頭著者記述言語：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 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

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

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

Physical Review A 96 ( 6 ) 063827 2017年

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

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 μm 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

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

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

Review of Scientific Instruments 88 ( 6 ) 2017年

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 Institute of Physics Inc.

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.

DOI： 10.1063/1.4989405

Simultaneous measurements of superradiance at multiple wavelength from helium excited states: II. Analysis 査読

Ohae, C., Harries, J.R., Iwayama, H., Kawaguchi, K., Kuma, S., Miyamoto, Y., Nagasono, M., Nakajima, K., Nakano, I., Shigemasa, E., Sasao, N., Uetake, S., Wakabayashi, T., Yoshimi, A., Yoshimura, K., Yoshimura, M.

Journal of the Physical Society of Japan 85 ( 3 ) 2016年

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

Previous experimental studies of superradiance (SR) in multi-level systems have been explainable using the predictions of the well-known simple two-level SR model. However our recent study [K. Nakajima et al., J. Phys. Soc. Jpn. 84, 054301 (2015)] using EUV free-electron laser excitation of helium atoms, where SR was observed at wavelengths of 502, 668, and 728 nm, revealed behaviour which necessitates a full multi-level treatment of the SR development. In this paper, we report simulations of the initial excitation by the FEL pulses, and the subsequent development of multi-level SR. The results of the simulation reproduce the experimental findings, and reveal that competitive SR on two transitions with a common upper level plays an important role in the development of the system.

DOI： 10.7566/JPSJ.85.034301

DETECTION of HF TOWARD PKS 1830-211, SEARCH for INTERSTELLAR H<inf>2</inf>F⁺, and LABORATORY STUDY of H<inf>2</inf>F⁺ and H<inf>2</inf>Cl⁺ DISSOCIATIVE RECOMBINATION 査読

Kawaguchi, K., Muller, S., Black, J.H., Amano, T., Matsushima, F., Fujimori, R., Okabayahsi, Y., Nagahiro, H., Miyamoto, Y., Tang, J.

Astrophysical Journal 822 ( 2 ) 2016年

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 extragalactic observations of two fluorine-bearing species, hydrogen fluoride (HF) and fluoronium (H2F+), in the z = 0.89 absorber in front of the lensed blazar PKS 1830-211 with the Atacama Large Millimeter/submillimeter Array. HF was detected toward both southwest and northeast images of the blazar, with column densities > 3.4 x 10(14) cm(-2) and 0.18 x 10(14) cm(-2), respectively. H2F+ was not detected, down to an upper limit (3 sigma) of 8.8 x 10(11) cm(-2) and an abundance ratio of [H2F+]/[HF] <= 1/386. We also searched for H2F+ toward the Galactic sources NGC 6334 I and W51C, and toward Galactic center clouds with the Herschel HIFI spectrometer.(6) The upper limit on the column density was derived to be 2.5 x 10(11) cm(-2) in NGC 6334 I, which is 1/68 of that for H2Cl+. In constrast, the ortho transition of H2Cl+ is detected toward PKS 1830-211. To understand the small abundance of interstellar H2F+, we carried out laboratory experiments to determine the rate constants for the ion-electron recombination reaction by infrared time-resolved spectroscopy. The constants determined are k(e)(209 K) = (1.1 +/- 0.3) x 10(-7) cm(3) s(-1) and (0.46 +/- 0.05) x 10(-7) cm(3) s(-1) for H2F+ and H2Cl+, respectively. The difference in the dissociative recombination rates between H2F+ and H2Cl+ by a factor similar to 2 and the cosmic abundance ratio [F]/[Cl] approximate to 1/6 are not enough to explain the much smaller abundance of H2F+. The difference in the formation mechanism of H2F+ and H2Cl+ in interstellar space would be a major factor in the small abundance of H2F+.

DOI： 10.3847/0004-637X/822/2/115

Single-atom response of helium atoms to pulses from an EUV free-electron laser: Implications for the subsequent development of superfluorescence 査読

Harries, J.R., Ohae, C., Kuma, S., Nakajima, K., Togashi, T., Miyamoto, Y., Sasao, N., Iwayama, H., Nagasono, M., Yabashi, M., Shigemasa, E.

Physical Review A 94 ( 6 ) 2016年

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

Using multilevel (161-level) numerical simulations beyond the rotating-wave approximation, we investigate the single-atom response of helium to intense pulses of radiation with properties characteristic of a self-amplified spontaneous emission (SASE) free-electron laser (FEL) source, and central wavelengths resonant with 1snp excitation (n = 3,4). The results show a complete breakdown of the two-level approximation and suggest that, under typical experimental conditions, levels other than the resonant level are significantly populated. We discuss the implications for the subsequent development of superfluorescence (a collective effect) from the excited atomic medium and compare the results to recent experiments.

DOI： 10.1103/PhysRevA.94.063416

Recent progress of SPAN towards neutrino mass spectroscopy 査読

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年

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：IOP PUBLISHING LTD

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

その他リンク： http://orcid.org/0000-0002-0567-6881

FPGAを用いた高速デジタル制御によるトランスファー共振器の周波数安定化

岡井晃一, 原秀明, 増田孝彦, 宮本祐樹, 笹尾登, 植竹智

日本物理学会講演概要集 71 528 - 528 2016年

記述言語：日本語出版者・発行元：一般社団法人日本物理学会

<p>大気中に置いたトランスファー共振器を介して複数のレーザー間で安定性を伝達する場合、大気圧の変化などに伴う空気の屈折率変化の波長依存性が異なるため伝達に支障をきたす。そのため、トランスファー共振器を利用した周波数安定化システムでは周波数ドリフトが生じる。そこで、気圧を含む大気状態の変化による屈折率変化をリアルタイムに補正するシステムをFPGAにより構築する。本講演では屈折率補正方法およびシステムの詳細について報告する。</p>

DOI： 10.11316/jpsgaiyo.71.2.0_528

固体パラ水素振動準位を用いたコヒーレント二光子放出の観測

宮本祐樹, 原秀明, 増田孝彦, 植竹智, 笹尾登, 吉見彰洋, 吉村浩司, 吉村太彦

日本物理学会講演概要集 71 577 - 577 2016年

記述言語：日本語出版者・発行元：一般社団法人日本物理学会

<p>二光子吸収は良く知られた二光子過程であるが、逆過程である二光子放出の、特に固体中での報告は少ない。本研究では、固体パラ水素の振動準位をラマン過程によりコヒーレントに励起、さらに中赤外レーザーを照射することで二光子放出のレートを増幅し、観測することに成功した。固体パラ水素の振動状態は長いデコヒーレンス時間を持つため、中赤外レーザーを励起から100ns以上後に入射しても二光子放出が観測された。</p>

DOI： 10.11316/jpsgaiyo.71.2.0_577

EUV-FEL励起1s4pへリム原子集団における超蛍光・超放射の実験と数値計算

Harries James R, 岩山洋士, 久間晋, 宮本祐樹, 永園充, 大饗千彰, 富樫格, 中嶋享, 繁政英治, 笹尾登

日本物理学会講演概要集 71 541 - 541 2016年

記述言語：日本語出版者・発行元：一般社団法人日本物理学会

<p>1s4p励起共鳴波長52.2nmのEUV-FELで励起された原子集団から放出される超蛍光・超放射について報告する。実験では668nm(1s3d-1s2p)の超蛍光の遅延時間、パルス幅を測定した。この遷移における超蛍光発展のメカニズムを解明するために数値計算も行ったので詳細について報告する。</p>

DOI： 10.11316/jpsgaiyo.71.2.0_541

A streak camera study of superfluorescence at multiple wavelengths from helium atoms excited using free electron laser pulses (vol 48, 105002, 2015) 査読

James R. Harries, Hiroshi Iwayama, Mitsuru Nagasono, Tadashi Togashi, Makina Yabashi, Susumu Kuma, Kyo Nakajima, Yuki Miyamoto, Chiaki Ohae, Noboru Sasao, Eiji Shigemasa

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 48 ( 15 ) 2015年8月

Infrared absorption spectra of SiF<inf>4</inf> and its clusters in solid parahydrogen 査読

Ooe, H., Miyamoto, Y., Kuma, S., Sasao, N., Kawaguchi, K.

Chemical Physics Letters 631-632 54 - 58 2015年

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 observed infrared absorption spectra of tetrahedral silicon tetrafluoride (SiF4) and its clusters in solid parahydrogen. The spectra were assigned by a temporal change of the peak intensity with annealing and previous studies in the gas and other matrices. It was found that the SiF4 monomer does not rotate in solid parahydrogen in spite of its small size and the absence of the permanent electric dipole moment. The dimer spectra are similar to those in the gas phase except for complicated sub-structures. Some other peaks were tentatively assigned to trimer and larger clusters. Clusters with other impurities were also observed. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2015.04.057

Pressure broadening of transitions in the CH<inf>3</inf>F υ<inf>4</inf> band using Stark modulated Lamb dips 査読

Okabayashi Y, Miyamoto Y, Tang J, Kawaguchi K

Chemical Physics Letters 619 144 - 147 2015年

A streak camera study of superfluorescence at multiple wavelengths from helium atoms excited using free electron laser pulses 査読

Harries, J.R., Iwayama, H., Nagasono, M., Togashi, T., Yabashi, M., Kuma, S., Nakajima, K., Miyamoto, Y., Ohae, C., Sasao, N., Shigemasa, E.

Journal of Physics B: Atomic, Molecular and Optical Physics 48 ( 10 ) 2015年

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 observation of superfluourescence at wavelengths (in air) of 501.6 nm, 667.8 nm, and 728.1 nm following the excitation of helium atoms with free-electron laser pulses at wavelengths of 53.7 nm (n = 3 excitation) and 52.2 nm (n = 4 excitation). The observed wavelengths of the superfluorescence pulses correspond to 1s3p-1s2s, 1s3d-1s2p, and 1s3s-1s2p transitions. Observation of superfluorescence on these transitions implies either competing cascade decays, or direct excitation of non-dipole allowed transitions. We have studied the time structure of the emitted pulses using a streak camera, and the results cannot be explained by straightforward considerations using the usual model for two-level superfluorescence.

DOI： 10.1088/0953-4075/48/10/105002

Early Negative Ion Studies Related to C6H- and Recent Ion Spectroscopy 査読

Kentarou Kawaguchi, Ryuji Fujimori, Hiroki Ooe, Yuki Miyamoto

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2010 (ICCMSE-2010) 1642 350 - 353 2015年

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：AMER INST PHYSICS

Through a spectral line survey observation with Nobeyama 45-m radio telescope in the 28-50 GHz region toward a late type star IRC+10216, a series of lines of a linear molecule was found in 1995. The rotational constant was determined to be 1376.8641(43) MHz, and the molecule is called B1377. After the detection, various studies related this species were carried out, which are presented in this paper, including Aoki's pioneering prediction and radio searches for NCO-, NCS-, and CCH-, etc. Finally, in 2006, McCarthy et al. succeeded in laboratory detection of the C6H- species by mm wave and FTMW spectroscopy and proved that the C6H- anion is B1377. We also report recent laboratory studies in the following topics :(1) time-resolved Fourier transform (FT) emission and absorption spectroscopy of molecular ions to obtain reaction rate constants, (2) FT infrared absorption spectrum of the H2F+ ion.

DOI： 10.1063/1.4906691

Erratum: A streak camera study of superfluorescence at multiple wavelengths from helium atoms excited using free electron laser pulses (Journal of Physics B: Atomic, Molecular and Optical Physics 48:105002(2015)) 査読

Harries, J.R., Iwayama, H., Nagasono, M., Togashi, T., Yabashi, M., Kuma, S., Nakajima, K., Miyamoto, Y., Ohae, C., Sasao, N., Shigemasa, E.

Journal of Physics B: Atomic, Molecular and Optical Physics 48 ( 15 ) 2015年

Externally triggered coherent two-photon emission from hydrogen molecules 査読

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

Progress of Theoretical and Experimental Physics 2015 ( 8 ) 2015年

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 INC

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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