Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/eftf/ifcs57587.2023.10272086

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1140/epjd/s10053-022-00437-z

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

DOI： 10.1103/PhysRevD.104.115006

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevD.104.115006/fulltext

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

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

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

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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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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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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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Other Link： http://www.nature.com/articles/s41586-019-1542-3

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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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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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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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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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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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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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Publishing type：Research paper (international conference proceedings)   Publisher：Sissa Medialab  

DOI： 10.22323/1.281.0174

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

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

The electric quadrupole moment of the Al-33(13)20 ground state, located at the border of the island of inversion, was obtained using continuous-beam beta-detected nuclear quadrupole resonance (beta-NQR). From the measured quadrupole coupling constant nu(Q) = 2.31(4) MHz in an alpha-Al2O3 crystal, a precise value for the electric quadrupole moment is extracted: vertical bar Q(s) (Al-33)vertical bar = 141(3) mb. A comparison with large-scale shell model calculations shows that Al-33 has at least 50% intruder configurations in the ground state wave function, favoring the excitation of two neutrons across the N = 20 shell gap. Al-33 therefore clearly marks the gradual transition north of the deformed Na and Mg nuclei towards the normal Z >= 14 isotopes.

DOI： 10.1103/PhysRevC.94.034312

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

DOI： 10.1140/epjd/e2016-70034-8

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

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

DOI： 10.11316/jpsgaiyo.71.1.0_332

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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

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

Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.71.2.0_577

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DOI： 10.11316/jpsgaiyo.71.1.0_436

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DOI： 10.11316/jpsgaiyo.71.1.0_435

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DOI： 10.11316/jpsgaiyo.71.1.0_437

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

DOI： 10.11316/jpsgaiyo.71.1.0_433

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

DOI： 10.1007/s10751-015-1203-3

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

DOI： 10.1007/s10751-014-1100-1

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

DOI： 10.1007/s10751-014-1113-9

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

DOI： 10.11316/jpsgaiyo.70.2.0_251

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.7566/JPSCP.6.020031

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Other Link： http://orcid.org/0000-0001-8122-5145

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPRINGER INTERNATIONAL PUBLISHING AG  

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

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

DOI： 10.1007/s10751-014-1109-5

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Other Link： http://link.springer.com/article/10.1007/s10751-014-1109-5/fulltext.html

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.7566/JPSCP.6.030004

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.7566/JPSCP.6.030067

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Publishing type：Research paper (scientific journal)   Publisher：Scientific Research Publishing, Inc.  

DOI： 10.4236/jmp.2015.67097

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

DOI： 10.11316/jpsgaiyo.70.1.0_244

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DOI： 10.11316/jpsgaiyo.70.1.0_246

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DOI： 10.11316/jpsgaiyo.70.1.0_247

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DOI： 10.11316/jpsgaiyo.70.1.0_668

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DOI： 10.11316/jpsgaiyo.70.1.0_86

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DOI： 10.11316/jpsgaiyo.70.1.0_245

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DOI： 10.11316/jpsgaiyo.70.1.0_249

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DOI： 10.11316/jpsgaiyo.70.2.0_252

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DOI： 10.7566/JPSCP.6.030070

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

We describe in this paper a fast and efficient method of producing a high density of barium (Ba) atoms in the D-1(2) metastable state, which is a candidate initial state for a new class of cooperative and coherent optical process called paired superradiance (PSR). In the experiment, Ba atoms are excited first by laser light to the P-1(1) state and then brought to the desired state D-1(2) via radiative transition in the superradiance (SR) mode. It is found that a production efficiency (from S-1(0) to D-1(2)) of more than similar to 30% is achieved within a time interval of a few nanoseconds for a Ba density n > 10(19) m(-3). Several key features of SR important for future PSR experiments are also studied.

DOI： 10.7566/JPSJ.83.044301

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MAIK NAUKA/INTERPERIODICA/SPRINGER  

We aim to measure the electric dipole moment (EDM) of a diamagnetic atom Xe-129 using an optical-detection nuclear spin maser technique. The relation of EDM in a diamagnetic atom to nuclear Schiff moment and fundamental sources generating it is discussed, and the present status for the development of our experimental setup is presented.

DOI： 10.1134/S1063779614010080

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS INC  

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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：E D P SCIENCES  

Uncertainty in the frequency precision of the planned experiment to search for a Xe-129 atomic electric dipole moment is dominated by drifts in the frequency shift due to contact interaction of Xe-129 with polarized Rb valence electrons. In order to suppress the frequency shift, a double-cell geometry has been adopted for the confinement of Xe-129 gas. A new process has been identified to take part in the optical detection of spin precession. The parameters controlling the oscillation of the maser in this new double-cell arrangement were optimized As a result, the frequency shift has been reduced by a factor of 10 or more from the former single-cell geometry.

DOI： 10.1051/epjconf/20146605005

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：E D P SCIENCES  

An experimental search for an electric dipole moment in the diamagnetic atom Xe-129 is in progress through the precision measurement of spin precession frequency using an active nuclear spin maser. A He-3 comagnetometer has been incorporated into the active spin maser system in order to cancel out the long-term drifts in the external magnetic field. Also, a double-cell geometry has been adopted in order to suppress the frequency shifts due to interaction with polarized Rb atoms. The first EDM measurement with the Xe-129 active spin maser and the He-3 comagnetometer has been conducted.

DOI： 10.1051/epjconf/20146605007

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

A method to produce spin-aligned rare isotope (RI) beams has been developed, where a scheme of two-step projectile fragmentation to produce the RI of interest with high spin alignment and a technique of momentum-dispersion matching are combined. Effectiveness of the present method was demonstrated in an experiment at the RIKEN RIBF, where an RI beam of Al-32 with spin alignment of 8(1)% was successfully produced from a primary beam of Ca-48, via an intermediate RI of Al-33. Figure of merit of the present method was found to be more than 50 times greater than that of the conventional method employing single-step projectile fragmentation. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2013.04.071

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

DOI： 10.1016/j.nimb.2013.08.057

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DOI： 10.1016/j.nimb.2013.08.059

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

The coherence decay of the v = 2 vibrational state (vibrons) of solid parahydrogen was measured via time-resolved coherent anti-Stokes Raman spectroscopy. We found that the decay curve has a non-exponential time profile in the time scale of 200 ns at a low temperature below 5 K and a low orthohydrogen impurity concentration (similar to 0.01%). This behavior, as also observed in the case of the v = 1 vibrons, represents a signature of band structure of the v = 2 state in the solid phase. The maximum coherence decay time of 50 ns in an exponential part was achieved, which shows excellence of the v = 2 state for coherent processes. We also found that finite temperatures, orthohydrogen impurities, and other structural inhomogeneity accelerate the decay, hiding the non-exponential feature of the vibron band. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773893]

DOI： 10.1063/1.4773893

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

The measurement of nuclear moments of a mu-second isomeric state have been successfully performed using the RIKEN Radioactive Ion Beam Facility. The Time Dependent Perturbed Angular Distribution technique was applied on the 43 S isomeric state produced by the fragmentation of a Ca-48 beam and selected with the BigRIPS spectrometer. Following the measurement of the known g-factor of the isomer the quadrupole moment of this state was measured. Its spectroscopic quadrupole moment vertical bar Q(S)vertical bar = 23( 3) efm(2) agreed with both shell model and beyond mean field calculations.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

Based on the technique of fragmentation-induced spin polarization combined with the beta-NMR method, we have conducted a series of ground-state nuclear-moment measurements in a region of light neutron-rich nuclei at RIKEN. The research has recently been extended also at GANIL. The ground-state studies will be further enhanced by the upgrade of RIPS proposed in the RIBF Phase-II program. Also, utilizing the technique of fragmentation-induced spin-orientation, nuclear-moment measurements of isomeric state were conducted. Remarkably, we have recently developed a method to produce highly spin-aligned RI beams in a new promising scheme. The method was first examined using BigRIPS, where a highly spin-aligned isomeric Al-32m beam was successfully produced through the two-step projectile fragmentation reaction.

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DOI： 10.1007/s10751-012-0682-8

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

The degree of freedom of spin in quantum systems serves as an unparalleled laboratory where intriguing quantum physical properties can be observed, and the ability to control spin is a powerful tool in physics research. We propose a method for controlling spin in a system of rare isotopes which takes advantage of the mechanism of the projectile fragmentation reaction combined with the momentum-dispersion matching technique. The present method was verified in an experiment at the RIKEN RI Beam Factory, in which a degree of alignment of 8% was achieved for the spin of a rare isotope Al-32. The figure of merit for the present method was found to be greater than that of the conventional method by a factor of more than 50.

DOI： 10.1038/NPHYS2457

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

A search for isomeric gamma decays among fission fragments from 345 MeV/nucleon U-238 has been performed at the RIKEN Nishina Center RI Beam Factory. Fission fragments were selected and identified using the superconducting in-flight separator BigRIPS and were implanted in an aluminum stopper. Delayed gamma rays were detected using three clover-type high-purity germanium detectors located at the focal plane within a time window of 20 mu s following the implantation. We identified a total of 54 microsecond isomers with half-lives of similar to 0.1-10 mu s, including the discovery of 18 new isomers in very neutron-rich nuclei: Ti-59(m), As-90(m), Se-92(m), Se-93(m), Br-94(m), Br-95(m), Br-96(m), Rb-97(m), Nb-108(m), Mo-109(m), Ru-117(m), Ru-119(m), Rh-120(m), Rh-122(m), Pd-121(m), Pd-124(m), Ag-124(m), and Ag-126(m), and obtained a wealth of spectroscopic information such as half-lives, gamma-ray energies, gamma-ray relative intensities, and gamma gamma coincidences over a wide range of neutron-rich exotic nuclei. Proposed level schemes are presented for Ti-59(m), Ga-82(m), Br-92(m), Br-94(m), Br-95(m), Rb-97(m), Rb-98(m), Nb-108(m), Zr-108(m), Mo-109(m), Ru-117(m), Ru-119(m), Rh-120(m), Rh-122(m), Pd-121(m), Ag-124(m), and Ag-125(m), based on the obtained spectroscopic information and the systematics in neighboring nuclei. The nature of the nuclear isomerism is discussed in relation to the evolution of nuclear structure.

DOI： 10.1103/PhysRevC.86.054319

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

Electric quadrupole moment Q of the Al-33 ground state has been measured by means of beta-NMR spectroscopy using a spin-polarized Al-33 beam produced in a projectile fragmentation reaction. The obtained Q moment, vertical bar Q(exp)(Al-33)vertical bar = 132(16) emb, shows a significant excess from the prediction of shell model calculations within the sd shell. The result indicates sizable admixing of pf intruder configurations in the ground state, demonstrating that the N = 20 shell closure certainly erodes in Al-33, a nucleus located on the border of the island of inversion. Comparison was made with predictions of the Monte Carlo shell model, and also a particle-vibration coupling model treating the neutron pairing correlations in the ground state of Al-33. Again, a significant admixture of pf intruder configurations to the Al-33 ground state was needed in both theoretical approaches to explain the observed large Q. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physletb.2012.07.030

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

We have constructed a Xe-129 nuclear spin oscillator which executes a self-sustained oscillation through an external feedback loop with optical detection of nuclear spin. The oscillator is capable of operating at frequencies much lower than the conventional nuclear spin maser. A method for efficient optical detection of spin has been developed and applied to the nuclear spin oscillator, and the frequency characteristics of the oscillator at low frequencies has been investigated. The spin oscillator was operated at frequencies 2.5-36 Hz. The frequency performance of the oscillator is discussed in relation to a planned search for an atomic electric dipole moment taking advantage of the present oscillator scheme. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physleta.2012.04.043

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

We report on the spectroscopic quadrupole moment measurement of the 7/2(1)(-) isomeric state in S-43(16)27 [E* = 320.5(5) keV, T-1/2 = 415(3) ns], using the time dependent perturbed angular distribution technique at the RIKEN RIBF facility. Our value, vertical bar Q(s) vertical bar = 23(3) efm(2), is larger than that expected for a single-particle state. Shell model calculations using the modern SDPF-U interaction for this mass region reproduce remarkably well the measured vertical bar Q(s) vertical bar, and show that non-negligible correlations drive the isomeric state away from a purely spherical shape.

DOI： 10.1103/PhysRevLett.108.162501

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

DOI： 10.1103/physrevc.85.034313

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Other Link： http://orcid.org/0000-0001-8864-369X

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPRINGER  

Immediately after the GeV-implantation of Mn-57 nuclei produced by the RIKEN-RIBF facility, Mn-57/Fe-57 Mossbauer spectra in Si-solar cells are measured under light illumination. Comparing with the spectrum of p-type multi-crystalline-Si, the broad spectra of the solar cell under operation can be analyzed as a superposition of interstitial and substitutional Fe components with different charge states. The charge states of Fe impurities are created by the excess carrier injection followed by a directional carrier flow in the p-n junction. The present results provide us a possibility to clarify the carrier trapping process at the Fe impurities in Si-solar cells.

DOI： 10.1007/s10751-011-0424-3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS INC  

We systematically investigate the new experimental method of using atoms or molecules to measure the important parameters of neutrinos that are still to be determined: the absolute mass scale, the mass hierarchy pattern (normal or inverted), the neutrino mass type (Majorana or Dirac), and the CP-violating phases, including Majorana phases. Most of these observables are difficult to measure in neutrino oscillation experiments. There are advantages to using atomic targets, such as the closeness of available atomic energies to anticipated neutrino masses, over nuclear target experiments such as the end point spectrum of beta decay and two-electron line spectrum in the neutrinoless double beta decay, both of which address some of the overlapping objectives with atomic/molecular experiments. A disadvantage of using atomic targets, the smallness of rates, is overcome by the macro-coherent amplification mechanism. The atomic or molecular process we use is a cooperative deexcitation of a collective body of atoms in a metastable level vertical bar e > emitting a neutrino pair and a photon: vertical bar e > -> vertical bar g > + gamma + nu(i)nu(j), where nu(i)s are neutrino mass eigenstates. The macro-coherence is developed by trigger-laser irradiation of two colors, which frequently causes the two-photon process vertical bar e > <-> vertical bar g > + gamma + gamma, vertical bar e > + gamma <-> vertical bar g > + gamma inside the target. We discuss important aspects of the macro-coherence development in detail, by setting up the master equation for the target Bloch vector (whose components are population difference and medium polarization) and the propagating electric field. Our master equation includes the effects of phase decoherence of medium polarization and decay of population difference. The spectral rate (the number of events per unit time) of macro-coherent radiative emission of a neutrino pair has three parts, and is given by a factorized formula of the form (overall omega-independent rate denoted by Gamma(0)) x (spectral shape function denoted by I (omega)) x (time-evolving dynamical factor), where omega is the photon energy. The constant factor Gamma(0) determines the overall rate in the unit of 1/time, and for Xe it is of the order of 1Hz(n/10(22) cm(-3))(3) (V/10(2) cm(3)). The dynamical factor is time dependent and is given by the space integrated quantity, over the entire target, of the product of the magnitude squared of the coherent polarization and the field strength (in the units of the maximally extractable energy density) stored inside the target. The asymptotic value of the time-evolving dynamical factor is given by the contribution of the field condensate accompanied by macroscopic coherence, which is calculated using the static limit of the master equation. With an appropriate choice of heavy target atoms or molecules such as Xe and I-2 that have a large M1 x E1 matrix element between vertical bar e > and vertical bar g >, we show that one can determine three neutrino masses along with distinction of the mass hierarchy pattern (normal or inverted) by measuring the spectral shape I (omega).If one uses a target of available energy of a fraction of 1 eV, the most experimentally challenging observable, the Majorana CP phases may be determined, comparing the detected rate with differences of theoretical expectations which exist at the level of several percent. The Majorana CP-violating phase is expected to be crucial to the understanding of the matter-antimatter imbalance in our universe. Our master equation, when applied to E1 x E1 transitions such as pH(2) vibrational Xv = 1 -> 0, can describe explosive paired superradiance events in which most of the energy stored in vertical bar e > is released in the order of a few nanoseconds. The present paper is intended to be self-contained, explaining some details of related theoretical works in the past, and reports on new simulations and the ongoing experimental efforts of the project to realize neutrino mass spectroscopy using atoms/molecules.

DOI： 10.1093/ptep/pts066

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IOP PUBLISHING LTD  

To produce a radioactive-isotope (RI) beam with high spin alignment, we have developed a novel method, the two-step projectile-fragmentation (PF) method, that employs momentum-dispersion matching. An on-line experiment to produce Al-32 from Ca-48 via Al-33 was performed at RIKEN RI Beam Factory. In the experiment, we succeeded in producing approximately 8% spin alignment in an RI beam of Al-32. In this paper, we focus on evaluating the magnitude of spin alignment realized in one-nucleon removal from Al-33.

DOI： 10.1088/1742-6596/381/1/012090

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

We report on the spectroscopic quadrupole moment of the 7/2 isomer state [E*=320.5(5) keV, T-1/2=415(5) ns, vertical bar Q(s)vertical bar=23(3) efm(2)] in the neutron-rich S-43 nucleus, using the Time Dependent Perturbed Angular Distribution (TDPAD) method at RIKEN. The measured vertical bar Qs vertical bar is larger than that expected for a single particle state. Comparison to shell model calculations performed using the SDPF-U interaction, show that correlations drive the isomeric state away from a purely spherical shape.

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Ultra-cold neutron (UCN) is attractive for a search of the neutron electric dipole moment (nEDM). It is crucial to store UCNs with high density in a bottle for nEDM measurement apparatus. To increase the density, time focusing technique can be useful, where slow neutrons are accelerated and fast neutrons are decelerated by using magnetic potential. This device is called rebuncher. The rebuncher consists of a gradient magnet, RF coil, and neutron guide. The magnet generates a field gradient of 3.5 T/m (from 1 T to 0.2 T within 24 cm) in the longitudinal direction. By using anisotropic inter-poles, the magnet is compact and keeps the gradient uniform. The fabricated magnet showed good performance as designed. © 2012 IEEE.

DOI： 10.1109/TASC.2012.2183569

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

Frequency characteristics of a Xe-129 nuclear spin maser was studied, which is under development at Tokyo Institute of Technology for the search for a permanent electric dipole moment in diamagnetic Xe-129 atom. Drifts in the solenoid current and cell temperature were found to be the most influential factors on the maser frequency. From correlation coefficient analysis, there seem to exist other origins of frequency fluctuation, such as phase drifts in the maser oscillation. In order to improve the stability of the maser frequency, the intensity of the pumping laser required to fully polarize Xe-129 nuclei was evaluated. Construction of a polarization assessment system for Xe-129 gas cells and development of a new scheme of current stabilization are also remarked. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physe.2010.07.066

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IOP PUBLISHING LTD  

Developments are in progress aiming at the search for a permanent Electric Dipole Moment (EDM) in (129)Xe atom using a low-frequency nuclear spin maser. In the EDM experiment, drifts in the applied static magnetic field in a long time scale are the dominating source of errors in frequency determination The stability of the applied field and its monitoring by use of a high sensitivity magnetometer are thus the indispensable part of the EDM experiment. We are developing a magnetometer based on the Nonlinear Magneto-Optical Rotation (NMOR) effect in Rb atom. The sharp response to the magnetic field in this apparatus relies on a long relaxation time of the atomic spin alignment induced by linearly polarized laser light, and thus the suppression of the atomic decoherence should be essential for its sensitivity. Coating the inner walls of the cell with an antirelaxation layer, introducing a buffer gas in the cell and cancelling the transverse magnetic field should be effective in preventing atoms from depolarization. We obtained several NMOR spectra for Rb in cylindrical cells in such attempts. Up to now a sensitivity of delta B=1.5 x 10(-5) G has been attained in the present setup.

DOI： 10.1088/1742-6596/312/10/102015

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IOP PUBLISHING LTD  

Magnetic field stabilization is a crucial condition parameter for many kinds of ultra-high precision measurements such as a search for an electric dipole moment (EDM). The instability of magnetic field strength often arises from the drift of current flow in a solenoid coil to generate the magnetic field. For our EDM search experiment with maser oscillating diamagnetic (129)Xe atoms, we have developed a new stabilized current source based on a feedback system which is devised to correct the amount of current flow measured precisely with high-precision digital multimeter and standard resistor. Using this new current source, we have successfully reduced the drifts of coil current by at least a factor of 100 compared to commercially available current sources.

DOI： 10.1088/1742-6596/312/10/102005

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IOP PUBLISHING LTD  

Present status of the development of a nuclear spin maser for a (129)Xe atomic EDM search is reported. We studied the frequency behavior of the spin maser presently under operation, and found that the drift in the frequency is correlated with the maser amplitude drift. Also, a high-voltage application system for the (129)Xe precession cell was constructed. The leakage current measured is at present on the level of nA when a high voltage of 10 kV was applied, and is a subject of improvement to be achieved in near future.

DOI： 10.1088/1742-6596/312/10/102008

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IOP PUBLISHING LTD  

Development of a nuclear spin oscillator intended for the experimental search for an electric dipole moment in Xe-129 atom is reported. The spin oscillation is brought about by polarizing Xe-129 nuclear spins by spin exchange with optically polarized Rb atoms, detecting the spin precession through the transmission of a circularly polarized laser light, and applying a feedback field according to the detected spins. Until present, a frequency precision, in a measurement time of T = 45,000 s, of delta nu = 5.2 nHz has been achieved.

DOI： 10.1088/1742-6596/302/1/012039

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELSEVIER SCIENCE BV  

The development of a nuclear spin oscillator system, namely a spin maser with an external feedback, for use in the search for Xe-129 atomic EDM is presented. By introducing a new current source for the B-0 field solenoid, drifts in the maser frequency were remarkably suppressed. This in turn clearly brought out the correlation between the maser frequency and the environmental field. Correcting for the effect of the environmental field, the frequency precision of 5 nHz in the measurement time of 45,000 s was attained. Origins of the remaining drifts in the maser frequency are now under investigation.

DOI： 10.1016/j.phpro.2011.06.024

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELSEVIER SCIENCE BV  

We have been developing a high sensitivity atomic magnetometer for atomic EDM experiments using a low-frequency nuclear spin maser. In the developed nuclear spin maser of Xe-129, suppression of drift and fluctuation in the magnetic field is one of the important issues. The magnetometer being developed for spin maser EDM experiments utilizes the nonlinear magneto optical rotation (NMOR) effect in Rb atomic vapor. The enhancement of the optical rotation in a small magnetic field relies on the long spin-coherence time of Rb atoms in a vapor cell. The NMOR spectrum was measured by using fabricated Rb cells coated with an anti-relaxation material. The NMOR spectrum dependence on laser frequency, cell coating, and laser beam diameter were investigated. The magnetic sensitivity at present is 0.2 mu G/root Hz from observed NMOR and noise spectra.

DOI： 10.1016/j.phpro.2011.06.043

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Publishing type：Research paper (international conference proceedings)  

A gradient DC magnet is designed using 3D magnetic field analysis code. This magnet, referred to as a B magnet, is one of the key elements of a time-focusing device for ultra-cold neutrons (UCNs) based on a radio frequency gradient flipper - a so-called rebuncher. The magnet generates a guide and a potential field that interacts with the magnetic moment of UCNs and its main body comprises a C-shaped yoke made from iron. A field gradient is generated by a pole arrangement that includes an anisotropic inter-pole, which causes the fringe field to be uniform in the longitudinal direction even when the pole gap distance changes. The designed magnet has the following properties: (1) a maximum B-field of 10 kGauss, decreasing to 2 kGauss at a longitudinal distance of 25 cm, with a gradient of less than 400 Gauss/cm, (2) variations in the fringe field along the y direction is less than 4% over a range of -3 cm≤ y ≤ 3 cm at any z position in the spin-flipping region. Tracking simulations show that the B magnet is capable of accepting UCNs in the velocity range 2.3∼3.3 m/s. © 2011 Published by Elsevier B.V. 0 0

DOI： 10.1016/j.phpro.2011.06.013

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.66.2.1.0_91_3

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Publishing type：Research paper (international conference proceedings)  

We have been developing a new nuclear laser spectroscopic method "OROCHI" for determining spins and moments of exotic RIs. This is a method based on the combination of superfluid helium as a stopper of radioactive isotope (RI) beam and in-situ laser spectroscopy of RI atoms. This unique method will enable us to measure nuclear spins and electromagnetic moments of extremely low yield RI (less than 1 particle per second). To confirm the feasibility of this method for rare radioisotopes, we carried out the first on-line experiment with a 87Rb beam, aiming at evaluating the minimum beam intensity required for the measurement. The LIF (Laser Induced Fluorescence) photons from the 87Rb atoms stopped in He II are successfully observed in the on-line experiment. The obtained LIF intensity is nearly consistent with the intensity calculated from the photo-absorption cross section of atoms in He II.

DOI： 10.1088/1742-6596/302/1/012054

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.66.1.1.0_99_2

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

DOI： 10.1143/jpsj.79.073201

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPRINGER  

Electric quadrupole coupling constant eqQ/h of the extremely proton-rich Al-23 (wI(pi) = 5/2(+), T-1/2 = 0.47 s) nucleus implanted into an Al2O3 single crystal has been measured for the first time, using the beta-ray detecting nuclear quadrupole resonance method (beta-NQR) in a high magnetic field. As a preliminary result, the quadrupole coupling constant was determined as vertical bar eqQ/h(Al-23)vertical bar = 2.66 +/- 0.77 MHz. Using the quadrupole coupling constant of Al-27 in Al2O3 as a reference, the Q moment of the ground state of Al-23 was extracted as vertical bar Q(Al-23)vertical bar similar to 160 mb, which is well explained by the shell model calculation in the sd-shell model space with the USD interaction.

DOI： 10.1007/s10751-010-0262-8

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The β-NMR study of short-lived nucleus 58Cu (Iπ = 1+, T1/2 = 3.2 s) in Si has been performed. Spin polarization of 58Cu induced by the charge exchange reaction of 58Ni was observed in Si at 15 K. The 58Cu magnetic moment {pipe}μ[58Cu]{pipe} = (0.46±0.03)μN deduced from the β-NMR spectrum is consistent with the previous results on the laser spectroscopy. The present result shows that the 58Cu nucleus is promising as a new nuclear probe for the microscopic study of Cu impurities in Si. © 2010 Springer Science+Business Media B.V.

DOI： 10.1007/s10751-010-0249-5

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

The nuclear electric quadrupole moment (Q moment) of the neutron-rich nucleus Al-33 (I = 5/2, T-1/2 = 41 ms) has been measured by the beta-ray detected nuclear quadrupole resonance (beta-NQR) method for the first time. The Al-33 nucleus is considered to be on the border of the island of inversion within which a significant intrusion of the pf orbits occurs across the N = 20 shell gap and the intrusion causes an anomalous enhancement of the Q moment. Polarized Al-33 nuclei were produced from S-36 (77.5MeV/u) beams through the fragmentation process and separated by LISE fragment separator at GANIL. The Al-33 nuclei were implanted into a Al2O3 single-crystal plate and the beta-NQR spectrum was successfully obtained.

DOI： 10.1140/epja/i2009-10885-3

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

DOI： 10.1103/physrevc.80.037306

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

DOI： 10.1103/physrevc.79.027301

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

A nuclear spin maser is operated at a low static field through an active feedback scheme based on an optical nuclear spin detection and succeeding spin control by a transverse field application. The frequency stability of this optical-coupling spin maser is improved by installation of a low-noise current source for a solenoid magnet producing a static magnetic field in the maser operation. Experimental devices for application of the maser to EDM experiment are being developed.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

Nuclear moment studies on nuclei far from the P-stability line, performed by taking advantage of the projectile fragmentation reaction, are reviewed. A method to produce spin polarization/alignment in the projectile fragments was developed and utilized for the beta-NMR/NQR measurements. Several new findings in nuclear structure physics were obtained from the nuclear moment experiments done with these techniques.

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

The electric quadrupole coupling constant of the Al-31 ground state is measured to be nu(Q) = vertical bar eQV(zz)/h vertical bar = 2196(21) kHz using two different beta-NMR (Nuclear Magnetic Resonance) techniques. For the first time, a direct comparison is made between the continuous If technique and the adiabatic fast passage method. The obtained coupling constants of both methods are in excellent agreement with each other and a precise value for the quadrupole moment of Al-31 has been deduced: vertical bar Q(Al-31)vertical bar = 134.0(16) mb. Comparison of this value with large-scale shell-model calculations in the sd and sdpf valence spaces Suggests that the Al-31 ground state is dominated by normal sd-shell configurations with a possible small contribution of intruder states. The obtained value for vertical bar Q(Al-31)vertical bar and a compilation of measured quadrupole moments of odd-Z even-N isotopes in comparison with shell-model calculations shows that the proton effective charge e(p) = 1.1e provides a much better description of the nuclear properties in the sd-shell than the adopted value e(p) = 1.3e. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physletb.2009.06.043

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.64.1.1.0_80_4

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.64.1.1.0_80_2

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

DOI： 10.1016/j.nimb.2008.05.111

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

DOI： 10.1143/JPSJ.77.095001

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Other Link： http://orcid.org/0000-0003-1971-4313

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

A nuclear spin maser of a new type, that employs a feedback scheme based on optical nuclear spin detection, has been fabricated. The spin maser is operated at a low static field of 30 mG by using the optical detection method. The frequency stability and precision of the spin maser have been improved by a highly stabilized current source for the static magnetic field. An experimental setup to search for an electric dipole moment (EDM) in (129)Xe atom is being developed.

DOI： 10.1007/s10751-008-9630-z

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

The online time-differential perturbed angular correlation (TDPAC) method was applied to a study of the physical states of a probe F-19, the beta(-) decay product of O-19 (t(1/2) = 26.9 s), implanted in highly oriented pyrolytic graphite. The observed magnitude of the electric field gradient at the probe nucleus, vertical bar V-zz vertical bar = 2.91(17) x 10(22) V m(-2), suggests that the incident O-19 atoms are stabilized at an interlayer position with point group C-3v. Exhibiting observed TDPAC spectra having a clear sample-to-detector configuration dependence, we demonstrate the applicability of the present online method with a short-lived radioactive O-19 beam. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nimb.2007.11.001

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

DOI： 10.1007/s10751-008-9705-x

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.63.2.1.0_65_2

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

At the RI-beam facility of the RIKEN, Mn-57/Fe-57 isotopes are separated and implanted into n-type FZ-Si (6 x 10(16) As/cm(3)), and subsequently the atomic jump processes of Fe-57 in the Si matrix are observed by Mossbauer spectroscopy on a time scale of 100 ns between 330 and 1200 K. The spectra consist of two components due to "interstitial Fe" and "substitutional Fe", both of which yield the same isomer shifts as those reported in p-type Si, showing long-range diffusion with increasing temperature. The spectra are compared with those simulated from a theoretical model. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2007.08.122

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

The electric quadrupole moments for the ground states of Al-32 and Al-31 have been measured by the beta ray-detected nuclear quadrupole resonance method. Spin-polarized Al-32 and Al-31 nuclei were obtained from the fragmentation of Ar-40 projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal alpha-Al2O3 stopper. The measured Q moment of Al-32, vertical bar Q(Al-32)vertical bar = 24(2) mb, is in good agreement with a conventional shell-model calculation with a full sd model space and empirical effective charges, while that of Al-31 is considerably smaller than the sd calculations.

DOI： 10.1007/s10751-008-9685-x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：EDP SCIENCES S A  

Ground-state magnetic-dipole moments (mu) of Al30-32 and electric quadrupole moments (Q) of Al-31,Al- 32 have been measured with the beta-NMR method using spin- polarized radioactive-isotope beams produced in projectile-fragmentation reactions. Beams of Al30-32 were obtained by using RIKEN projectile-fragment separator RIPS after the fragmentation of Ar-40 projectiles at an energy of E = 95AMeV on a Nb-93 target. The obtained mu(exp)[Al30-32] and Q(exp)[Al-32] values agree well with shell-model calculations within the sd shell using the USD interaction. Also, Q(exp)[Al-31] was found to be small. Thus, we can conclude that these aluminum isotopes are located outside the island of inversion.

DOI： 10.1140/epjst/e2007-00299-y

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

A new method to produce spin-polarized radioactive nuclear beams has been developed, which takes advantage of the low-energy transfer reaction in inverse kinematics. The method provides beam energies of a convenient range so that they may be implanted in a thin stopper, yet allowing the stopper to be spatially separated from the production target. The presence of polarizations of sizes at least vertical bar P vertical bar similar to 0.5% has has been confirmed for a (17)N beam obtained from (9)Be((18)O, (17)N) reaction at theta(Lab) similar to -1.7 degrees.

DOI： 10.1007/s10751-008-9626-8

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

The electric quadrupole moment Q for the ground state of Al-32 has been measured using the beta-NMR technique. Spin-polarized Al-32 nuclei were obtained from the fragmentation of Ar-40 projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal alpha-Al2O3 stopper. The quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value, vertical bar Q((32)Alg.s.)vertical bar = 24(2) mb, is remarkably small as compared with other Al isotopes, but is well explained by shell model calculations within the sd shell. The present result indicates that Al-32 has a normal sd-shell structure, in contrast to the neighboring N = 19 isotone Mg-31 for which a strongly deformed intruder ground state has been reported to occur. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1036/j.physletb.2007.01.063

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

The electromagnetic moment is a sensitive probe to investigate microscopic structure. In order to measure the electromagnetic moment beta-NMR and beta-NQR methods are employed taking advantage of the fragment spin polarization produced by the fragmentation reaction. The measurement of the electric quadrupole moment for ground-state Al-31 has been been carried out by beta-NQR method. Spin-polarized Al-31 nuclei were obtained from the fragmentation of Ar-40 projectiles, and were implanted in alpha-Al2O3 stopper. The electric quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value is vertical bar Q(Al-31)vertical bar = 104(9) e center dot mb.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

We have constructed a nuclear spin oscillator of a new type, that employs a feedback scheme based on an optical spin detection and suceeding spin control by a transverse field application. This spin oscillator parallels the conventional spin maser in many points, but exhibits advantages and requirements that are different from those with the spin maser. By means of the optical-coupling nuclear spin oscillator, an experimental setup to search for an electric dipole moment (EDM) in a spin 1/2 diamagnetic atom Xe-129 is being developed.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

Spin-polarized radioactive ion beams are produced in the projectile fragmentation reaction induced by intermediate-energy heavy ion beams. The degree of spin polarization shows characteristic dependence on the outgoing momentum of the projectile fragment in the magnitude around 1 similar to 10 %. The qualitative behavior is well described by the kinematical model of the fragmentation process. Recently, we have successfully produced spin-polarized beams of aluminum isotopes in the mass A similar to 30 region via the fragmentation of 95 MeV/u Ar-40 projectiles. The magnetic moments of Al-30 and Al-32 and the electric quadrupole moments of Al-31 and Al-32 have been measured using the beta-NMR technique with the polarized RI beams of the Al isotopes.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

The electric quadrupole moment Q for the ground state of Al-32 has been measured using the beta-NMR technique. Spin-polarized Al-32 nuclei were obtained from the fragmentation of 40 Ar projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal alpha-Al2O3 stopper. The quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value, vertical bar Q(Al-32(g.s.))vertical bar = 24(2) mb, was well reproduced by shell model calculations within the sd shell, indicating that Al-32 is a normal sd-shell nucleus. The result is in sharp contrast to the strongly deformed nuclei Mg-32 and Mg-31 neighboring the Al-32 isotope.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

Precision measurement of nuclear beta decay correlations at newly constructing RIKEN-RIBF and KEK-TRIAC is planned. Measurements of beta neutrino correlation and T-violating electron transverse polarization using spin polarized RI beams are aimed to be performed using slow radioactive nuclei.

DOI： 10.1063/1.2750766

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

The new scheme to produce a spin-polarized RI beam is being developed, in which the atomic beam resonance method is utilized for spin polarization. A gas-filled chamber to stop the incoming RI ions and to drift them into vacuum area has been developed. The measurement of RI-stopping in the gas was performed, and experiments for drifting and extracting of the stopped ions are now being performed. The status of the R&D for realizing the scheme is reported in this letter.

DOI： 10.1063/1.2750910

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

Based on the technique of fragment-induced spin polarization combined with the beta-NMR method, we have recently carried out experiments at RIKEN to measure nuclear moments of neutron-rich aluminum isotopes. In the measurements, the nuclear magnetic-dipole moments of Al-30,Al- 32 and the electric-quadrupole moments of Al-31,Al-32 have been determined. The obtained magnetic moments, as well as the other known magnetic moments of aluminum isotopes, agree well with shell model calculations with the USD interaction. The obtained quadrupole moments are smaller than those of Al-27,Al- 28, suggesting spherical shapes of Al-31,Al- 32. These results seem to suggest that Al-31 and Al-32 are located outside the island of inversion. In near future, studies on nuclear moments will be extended further in the RIKEN RIBF project, in which medium- and heavy-mass regions come within our scope by using superconducting fragment separator BigRIPS. Also, an upgrade program for the existing fragment separator RIPS is in progress. In the RIBF project, nuclear moments will be measured for isomer states as well as ground states.

DOI： 10.1063/1.2713507

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The electric quadrupole moment Q for the ground state of neutron-rich Al-31,Al-32 has been measured using beta-NMR method applied to spin-polarized projectile fragments. The obtained quadrupole moments are smaller than those of Al-27,Al-28, which suggests spherical shapes of Al-31,Al-32.

DOI： 10.1063/1.2746585

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

Based on the technique of fragment-induced spin polarization combined with the NMR method, a series of experiments has been carried out at RIKEN for the nuclear-moment measurement of light unstable nuclei. The measurement will be extended further in the RIKEN RIBF project, where radioactive-isotope beams in the medium- and heavy-mass regions will be produced at higher energies and with higher intensities compared with the RARF facility. Measurements of the isomeric-state nuclear moments of unstable nuclei will be started with BigRIPS by utilizing fragment-induced spin-orientation phenomena. Also, an upgrade program of the existing fragment separator RIPS is proposed in the phase-H program of RIBE Then, intense beams will be delivered to RIPS at E similar to 115 A MeV. This energy region is useful, not only because spin orientation is produced in the PF reaction but also they can be implanted into sample materials with limited thickness.

DOI： 10.1063/1.2750908

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Publishing type：Research paper (scientific journal)   Publisher：IOP Publishing  

DOI： 10.1088/1742-6596/49/1/018

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Physics Publishing  

The magnetic moment and electric quadrupole moment of 32Al (Z 13,N 19) have been measured. We performed β-NMR spectroscopy with spin-polarized 32Al nuclei produced via the projectile fragmentation reaction. Both the moments are well reproduced by full sd-shell model calculations using the USD effective interaction. The result has provided clear evidence that 32Al is located out of the island of inversion. © 2006 IOP Publishing Ltd.

DOI： 10.1088/1742-6596/49/1/030

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A device that produces a low-energy and largely spin polarized RI beam based on the atomic beam resonance method (RIABR) has been developed. We have performed measurements of stopping and drifting an incoming RI ion beam in a gas chamber, extraction of the ions into a vacuum region, and neutralization of the extracted low-energy ion beam. The drift efficiency of RI ions in a gas and the extraction efficiency at a Laval-type glass nozzle were found to be 0.72±0.04 and 0.033, respectively. The result of the experiment for the neutralization is also discussed. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physe.2005.06.031

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DOI： 10.1088/1742-6596/20/1/010

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

We have developed a nuclear spin maser in which highly polarized nuclei of the noble gas isotope Xe-129 oscillate at the low frequency of 34 Hz. The system is advantageous for detecting a small frequency shift of the nuclear spin precession. We are thus planning to apply this system to the search for an atomic electric dipole moment of Xe-129. We here report the development of the system and its performance.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Kluwer Academic Publishers  

The magnetic moments for 30Al and32Al have been measured by the β-NMR method with spin-polarized radioactive nuclear beams from the projectile-fragmentation reaction. The fragmentation processes that involved large numbers of removed nucleons, 10 and 8, from the projectiles 40Ar were successfully utilized to produce polarized 30Al and 32Al fragments. The obtained magnetic moments, μ30Al = (3.012± 0.021]μNand (μ32Al = (1.959 ± 0.019)μN, were reproduced well by shell model calculations within a model space of the full sd shell.

DOI： 10.1007/bf03032019

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

A technique for providing high-spin isomers as probes of the fusion reaction and the measurement of g-factor has been worked out at RIKEN. In the study of the fusion reaction 12C(145mSm, xn)157-xEr, the γ rays emitted from the fusion-evaporation residue 154Er have been successfully observed. The nuclear g-factor of the T1/2 = 28 ns high-spin isomer in 149Dy has been measured with the γ-ray TDPAD method. © 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nuclphysa.2004.09.141

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG  

A new high-spin isomer in Dy-150 has been observed at an excitation energy of 10.3 MeV by combining the inverse-kinematic reaction induced by a pulsed beam of Xe-132 and the gamma-ray recoil-shadow technique. The half-life of this isomeric state has been determined to be T-1/2=1.6+/-0.6 ns using the conventional centroid-shift method with the Pr-141(O-16, p6n)Dy-150 reaction at 165 MeV. The mechanism producing high-spin isomers in N=83,84 isotones is qualitatively discussed in terms of the difference of the neutron particle-hole configuration between the high-spin isomer and the lower-lying state.

DOI： 10.1140/epja/i2003-10150-y

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

DOI： 10.1140/epja/i2003-10150-y

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Based on the beta-NMR method with spin-polarized radioactive-isotope beams, we have been conducting a series of experiments at RIKEN for the measurement the magnetic moments and electric quadrupole moments of light unstable nuclei. From the systematic measurements of nuclear moments in the unstable nuclear region, the effects of the neutron excess on the structure have been discussed. In the mu-moment measurements of the nitrogen isotopes, the outward-directed deviation of mu(N-17) and mu(N-19) from the Schmidt value were observed. In the case of Q-moment, our experimental data show large discrepancy from the shell-model predictions if neutron and proton effective charges are assumed to be constant. By introducing an isospin dependence to the effective charges, the observed Q-moments of boron isotopes can be explained. We also applied the result of mu-moment measurements to the I-pi assignment. Owing to the large difference of mu values among expected 1(pi) candidates, 1(pi)(C-17)=3/2(+) has been definitely assigned.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

The magnetic moment of N-19 was measured by using a beta-NMR method and a spin-polarized N-19 beam from the fragmentation reaction. As a result, the g value for the N-19 ground state, g = 0.61 +/- 0.03(preliminary), was obtained. The value was compared with those of N-15 and N-17. Contrary to shell-mode predictions that the g value should increase with increasing number of neutrons in the sd shell, the obtained g for N-19(g.s.) is significantly smaller than the g factor for N-17(g.s.).

DOI： 10.1142/9789812702401_0035

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

The nuclear g-factor of the T-1/2 = 28 ns high-spin isomer in Dy-149 has been measured using the gamma-ray time-differential perturbed angular distribution (TDPAD) technique with a pulsed beam of Xe-132. The experimental value g = +0.41(6) is in good agreement with a fully aligned multi-quasiparticle configuration pi (h(11/2)(2)) circle times nu(f(7/2)h(9/2)i(13/2)(d(3/2)(-2))(0)) This result indicates that only neutron particle-hole excitations across the N = 82 shell-closure occur at this isomeric state. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.nuclphysa.2003.09.007

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INST PHYSICS ACAD SCI CZECH REPUBLIC  

Low frequency spin precession of, the largely polarized Xe-129 nuclei was continuously maintained using the nuclear spin maser technique. This is aiming at the sensitive measurement of the energy shift of the nuclei which should be required in the search for the violation of the fundamental symmetries. It involves the optical detection system of the nuclear spin direction. and the artificial feedback system to maintain the spin precession beyond the intrinsic transverse relaxation time. Its operation was experimentally tested and the frequency properties were analyzed based on. the modified Bloch equations. The plans. of ail application,of the system to physical experiments are described.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

A new F-19 probe disintegrated from short-lived O-19 has been developed for the first time for time-differential perturbed angular correlation method. The angular correlation coefficient for the relevant cascade has been experimentally estimated to be A(22) = -0.17+/-0.01. As the first application of this technique to condensed matter physics, the probe was implanted in polycrystalline fullerene C-60. We have observed two contrastive perturbations acting on the probe nuclei, which reflect electrostatic and dynamic interactions with the extranuclear field.

DOI： 10.1023/A:1022216806445

DOI： 10.1023/a:1022216806445

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DOI： 10.1016/s0375-9601(02)01324-5

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The electric quadrupole moment of B-17 and the g-factor of C-17 were measured by using the fragmentation-induced nuclear polarization technique combined with the beta-NMR method. The experimental quadrupole moment of B-17 is found strikingly close to that of the neutron closed-shell isotope B-13, indicating a strong quenching of the neutron E2 core-polarization charge. From the result obtained for the C-17 g-factor, we can conclude that the ground-state spin-parity of C-17 is 3/2(+).

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Language：English   Publisher：Progress of Theoretical Physics  

The g-factor for the ^17C ground state was measured by means of the β-NMR spectroscopy with a spin-polarized fragment beam. From the tentative result |g(^17C)| = 0.5054(25), we conclude that the ground-state spin-parity for ^17C is 3/2^+.

DOI： 10.1143/PTPS.146.607

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The g-factor for the 17C ground state was measured by means of the β-NMR spectroscopy with a spin-polarized fragment beam. From the tentative result |g(17C)| = 0.5054(25), we conclude that the ground-state spin-parity for 17C is 3/2+.

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The electric quadrupole moment of B-17 was measured by means of spin polarized fragment beams produced by the projectile fragmentation reaction. The experimental quadrupole moment of 17B was very close to that of neutron p-shell closed nucleus B-13. This result indicates that the neutron effective charge for B-17 is considerably smaller than the value commonly used in the sd-shell region.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

Magnetic dipole and electric quadrupole moments of nuclei in the light-mass neutron-rich region have been studied by taking advantage of spin-polarized radioactive nuclear beams that have been obtained from the projectile fragmentation reaction. Analyses of the results reveal a few interesting phenomena characteristic of nuclear structures in this region. In particular, we report in some detail the latest result on the magnetic moment of the 17 C ground state. The distinctly small value of the g-factor obtained, | g(C-17 | = 0.5054 +/- 0.0025, clearly excludes a I-pi = 1/2(+) candidate for the spin-parity assignment of this marginally bound nucleus, providing a reasonable account of the non-halo nature reported in recent breakup reaction experiments. Finally, future plans at the upcoming radioactive beam facility presently under construction at RIKEN are briefly mentioned.

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Beams of spin-polarized radioactive nuclei are produced in the projectile fragmentation reaction induced by intermediate-energy heavy ion beams, and are used for the measurement of magnetic dipole and electric quadrupole moments of nuclei in the regions far from stability. In this paper, after remarking the mechanism of fragment polarization and the experimental techniques to make use of it, we discuss the recent results obtained for the electromagnetic moments of light neutron-rich nuclei at RIKEN. Analyses of the observed magnetic moments in terms of shell models show intriguing results which imply that some of the basic nuclear properties, such as the order in energy of the single-particle orbits, the pairing energy between the excess neutrons, and the effective g(s)-factor for a halo nucleon, tend to alter as the degree of neutron excess increases. Also, the measured electric quadrupole moments reveal remarkable quenching of the E2 effective charge in nuclei with large N/Z ratios.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

We propose a new scheme of nuclear spin maser and have performed the experimental and theoretical analyses for its operation, aiming at the significant improvement, in sensitivity of neutron electric dipole moment (EDM). The proposed spin-masing scheme incorporates an artificial feedback mechanism, and is applicable to extremely low density systems of spins such as a bottled ensemble of UCNs. Its operation was experimentally demonstrated by using a spin-polarized Xe-129 gas as a model substance. The frequency analysis suggests that a frequency precision allowing a neutron EDM search with a sensitivity of 10(-28) ecm level is attainable by this maser scheme.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

For g-factor measurements of excited states of unstable nuclei, we have been developing a setup for the transient field experiment at RIKEN Accelerator Research Facility. For the preparation of ferromagnetic material, thick Gd foils have been annealed. In a test experiment using a Ne-22 beam, the projectile Coulomb excitation to the first excited state has been observed.

DOI： 10.1023/a:1020584316404

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DOI： 10.1016/s0370-2693(99)00219-1

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Nuclear magnetic resonance (NMR) of a radioactive nucleus N-18 has been observed through a change in the beta-ray asymmetry, by taking advantage of the fragment spin polarization in the projectile fragmentation reaction. To facilitate the experiment, a new scheme has been developed which allows assessment of the polarization prior to the resonance search in the beta-ray detected NMR experiment. The obtained magnetic moment /mu/ = 0.3279 +/- 0.0017 mu(N) and the electric quadrupole moment /Q/ = 12.1 +/- 1.2 mb are compared with shell-model calculations.

DOI： 10.1088/0954-3899/24/8/013

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DOI： 10.1016/s0168-9002(97)00842-5

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DOI： 10.1016/s0370-2693(96)01447-5

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DOI： 10.1103/physrevc.53.2142

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevC.53.2142/fulltext

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Spin-polarized radio active-isotope beams developed at RIKEN offer us the opportunity of studying structures of nuclei far from the stability line through the measurement of electromagnetic moments. The effects of the neutron excess on the structure are discussed through the systemic measurements of the mu-moments of nitrogen isotopes and the Q-moments of boron isotopes. We also applied the result of mu-moment measurements for C-17 to the spin-parity assignment of its ground state.

DOI： 10.1016/j.nuclphysa.2004.04.033

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By taking advantage of spin polarized radioactive nuclear beams from projectile fragmentation, combined with the beta-detected nuclear magnetic resonance technique, the magnetic dipole and the electric quadrupole moments were measured for a number of nuclei in the light, neutron-rich region. The obtained results show some intriguing systematical features which become apparent when compared with standard shell-model calculations, and thus seem to shed new light on the structure and interactions of nuclei in this region.

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.54.2.1.0_54_4

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.54.2.1.0_54_3

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：English   Publisher：ELSEVIER SCIENCE BV  

For use as a spin analyzer for low energy neutrons, a polarized He-3 gas system was developed at KEK. The polarization attained of He-3 at 3 atm determined as P-He = 40%, through the measurement of the transmission of unpolarized neutrons through the He-3 fell. The He-3 cell was used in the measurement of P-violating spin rotation of neutrons in the 0.734 eV p-wave resonance of the La-139+n system. As a result, a parity mixing matrix element xW = 1.04 +/- 0.40 meV was obtained. which is in agreement with the s- and p-wave resonance mixing model. An attempt is under way to improve the performance of the spin analyzer, by increasing the He-3 pressure and incorporating high-power diode lasers. So far we have obtained P-He = 12% at 20 atm.

DOI： 10.1016/S0168-9002(97)00843-7

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

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Event date： 2021.1.12 - 2021.1.15

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2020.2.4 - 2020.2.5

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

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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

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