研究者詳細 - 吉見　彰洋

論文 - 吉見　彰洋

分割表示 148 件中 61 - 80 件目／全件表示 >>

Development of an adiabatic field rotation system to measure spin polarization of unstable nuclei

Y. Ishibashi, N. Yoshida, H. Ueno, A. Yoshimi, Y. Ichikawa, Y. Abe, K. Asahi, M. Chikamori, T. Fujita, T. Furukawa, E. Hikota, D. Nagae, Y. Ohtomo, Y. Saito, H. Shirai, T. Suzuki, X.F. Yang, N. Sakamoto

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 317 714 - 716 2013年12月

Coherence decay measurement of v=2 vibrons in solid parahydrogen 査読

Susumu Kuma, Yuki Miyamoto, Kyo Nakajima, Atsushi Fukumi, Kentarou Kawaguchi, Itsuo Nakano, Noboru Sasao, Minoru Tanaka, Jian Tang, Takashi Taniguchi, Satoshi Uetake, Tomonari Wakabayashi, Akihiro Yoshimi, Motohiko Yoshimura

JOURNAL OF CHEMICAL PHYSICS 138 ( 2 ) 024507 2013年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Nuclear moments of mu-second isomeric fragments at BigRIPS 査読

R. Chevrier, J. M. Daugas, L. Gaudefroy, M. Hass, H. Haas, H. Ueno, N. Aoi, N. Fukuda, Y. Ichikawa, N. Inabe, M. Ishihara, D. Kameda, T. Kubo, T. Ohnishi, H. Takeda, H. Watanabe, A. Yoshimi, K. Asahi, T. Furukawa, H. Hayashi, H. Iijima, T. Inoue, Y. Ishii, T. Nanao, K. Suzuki, M. Tsuchiya, D. L. Balabanski, G. Georgiev, S. Cootenier, G. Neyens, M. Rajabali

FRENCH-JAPANESE SYMPOSIUM ON NUCLEAR STRUCTURE PROBLEMS: ORGANIZED IN THE FRAMEWORK OF FJNSP LIA AND EFES 33 - 39 2013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：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.

Production of spin-aligned RI beams via the two-step fragmentation reaction 査読

H. Ueno, Y. Ichikawa, Y. Ishii, T. Furukawa, A. Yoshimi, D. Kameda, H. Watanabe, N. Aoi, K. Asahi, D. L. Balabanski, R. Chevrier, J. M. Daugas, N. Fukuda, G. Georgiev, H. Hayashi, H. Iijima, N. Inabe, T. Inoue, M. Ishihara, T. Kubo, T. Nanao, T. Ohnishi, K. Suzuki, M. Tsuchiya, H. Takeda, M. M. Rajabali

FRENCH-JAPANESE SYMPOSIUM ON NUCLEAR STRUCTURE PROBLEMS: ORGANIZED IN THE FRAMEWORK OF FJNSP LIA AND EFES 40 - 45 2013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：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.

Nuclear spin maser and experimental search for Xe-129 atomic EDM 査読

T. Inoue, T. Furukawa, A. Yoshimi, Y. Ichikawa, M. Chikamori, Y. Ohtomo, M. Tsuchiya, N. Yoshida, H. Shirai, M. Uchida, K. Suzuki, T. Nanao, H. Miyatake, H. Ueno, Y. Matsuo, T. Fukuyama, K. Asahi

Hyp. Int. 220 59 - 63 2013年

Novel method for the production of spin-aligned RI beams in projectile fragmentation reaction with the dispersion matching technique 査読

Hyperfine. Interact. 220 47 - 51 2013年

Production of spin-controlled rare isotope beams 査読

Yuichi Ichikawa, Hideki Ueno, Yuji Ishii, Takeshi Furukawa, Akihiro Yoshimi, Daisuke Kameda, Hiroshi Watanabe, Nori Aoi, Koichiro Asahi, Dimiter L. Balabanski, Raphael Chevrier, Jean-Michel Daugas, Naoki Fukuda, Georgi Georgiev, Hironori Hayashi, Hiroaki Iijima, Naoto Inabe, Takeshi Inoue, Masayasu Ishihara, Toshiyuki Kubo, Tsubasa Nanao, Tetsuya Ohnishi, Kunifumi Suzuki, Masato Tsuchiya, Hiroyuki Takeda, Mustafa M. Rajabali

NATURE PHYSICS 8 ( 12 ) 918 - 922 2012年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Observation of new microsecond isomers among fission products from in-flight fission of 345 MeV/nucleon U-238 査読

D. Kameda, T. Kubo, T. Ohnishi, K. Kusaka, A. Yoshida, K. Yoshida, M. Ohtake, N. Fukuda, H. Takeda, K. Tanaka, N. Inabe, Y. Yanagisawa, Y. Gono, H. Watanabe, H. Otsu, H. Baba, T. Ichihara, Y. Yamaguchi, M. Takechi, S. Nishimura, H. Ueno, A. Yoshimi, H. Sakurai, T. Motobayashi, T. Nakao, Y. Mizoi, M. Matsushita, K. Ieki, N. Kobayashi, K. Tanaka, Y. Kawada, N. Tanaka, S. Deguchi, Y. Satou, Y. Kondo, T. Nakamura, K. Yoshinaga, C. Ishii, H. Yoshii, Y. Miyashita, N. Uematsu, Y. Shiraki, T. Sumikama, J. Chiba, E. Ideguchi, A. Saito, T. Yamaguchi, I. Hachiuma, T. Suzuki, T. Moriguchi, A. Ozawa, T. Ohtsubo, M. A. Famiano, H. Geissel, A. S. Nettleton, O. B. Tarasov, D. Bazin, B. M. Sherrill, S. L. Manikonda, J. A. Nolen

PHYSICAL REVIEW C 86 ( 5 ) 054319 2012年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Erosion of N=20 shell in Al-33 investigated through the ground-state electric quadrupole moment 査読

K. Shimada, H. Ueno, G. Neyens, K. Asahi, D. L. Balabanski, J. M. Daugas, M. Depuydt, M. De Rydt, L. Gaudefroy, S. Grevy, Y. Hasama, Y. Ichikawa, D. Kameda, P. Morel, T. Nagatomo, L. Perrot, Ch Stodel, J. -C. Thomas, Y. Utsuno, W. Vanderheijden, N. Vermeulen, P. Vingerhoets, E. Yagi, K. Yoshida, A. Yoshimi

PHYSICS LETTERS B 714 ( 2-5 ) 246 - 250 2012年8月

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

Low-frequency Xe-129 nuclear spin oscillator with optical spin detection 査読

A. Yoshimi, T. Inoue, T. Furukawa, T. Nanao, K. Suzuki, M. Chikamori, M. Tsuchiya, H. Hayashi, M. Uchida, N. Hatakeyama, S. Kagami, Y. Ichikawa, H. Miyatake, K. Asahi

PHYSICS LETTERS A 376 ( 24-25 ) 1924 - 1929 2012年5月

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

Is the 7/2(1)(-) Isomer State of S-43 Spherical? 査読

R. Chevrier, J. M. Daugas, L. Gaudefroy, Y. Ichikawa, H. Ueno, M. Hass, H. Haas, S. Cottenier, N. Aoi, K. Asahi, D. L. Balabanski, N. Fukuda, T. Furukawa, G. Georgiev, H. Hayashi, H. Iijima, N. Inabe, T. Inoue, M. Ishihara, Y. Ishii, D. Kameda, T. Kubo, T. Nanao, G. Neyens, T. Ohnishi, M. M. Rajabali, K. Suzuki, H. Takeda, M. Tsuchiya, N. Vermeulen, H. Watanabe, A. Yoshimi

PHYSICAL REVIEW LETTERS 108 ( 16 ) 162501 2012年4月

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

We 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

Isobaric analog resonances of the N=21 nucleus 35Si 査読

N. Imai, Y. Hirayama, Y. X. Watanabe, T. Teranishi, T. Hashimoto, S. Hayakawa, Y. Ichikawa, H. Ishiyama, S. C. Jeong, D. Kahl, S. Kubono, H. Miyatake, H. Ueno, H. Yamaguchi, K. Yoneda, A. Yoshimi

Physical Review C 85 ( 3 ) 2012年3月

Fe-57 charge states in MC-Si solar cells under light illumination after GeV-implantation of Mn-57 査読

Yutaka Yoshida, Kunifumi Suzuki, Yoshio Kobayashi, Takashi Nagatomo, Yuki Akiyama, Kenichi Yukihira, Kazuo Hayakawa, Hideki Ueno, Akihiro Yoshimi, Daisuke Nagae, Koichiro Asahi, Guido Langouche

HYPERFINE INTERACTIONS 204 ( 1-3 ) 133 - 137 2012年3月

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：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

Neutrino spectroscopy with atoms and molecules 招待査読

Atsushi Fukumi, Susumu Kuma, Yuki Miyamoto, Kyo Nakajima, Itsuo Nakano, Hajime Nanjo, Chiaki Ohae, Noboru Sasao, Minoru Tanaka, Takashi Taniguchi, Satoshi Uetake, Tomonari Wakabayashi, Takuya Yamaguchi, Akihiro Yoshimi, Motohiko Yoshimura

PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS 2012 ( 1 ) 04D002 2012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 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

Production of spin-aligned RI beam via two-step fragmentation with dispersion matching 査読

Y. Ichikawa, H. Ueno, Y. Ishii, T. Furukawa, A. Yoshimi, D. Kameda, H. Watanabe, N. Aoi, K. Asahi, D. L. Balabanski, R. Chevrier, J. M. Daugas, N. Fukuda, G. Georgiev, H. Hayashi, H. Iijima, N. Inabe, T. Inoue, M. Ishihara, T. Kubo, T. Nanao, T. Ohnishi, K. Suzuki, M. Tsuchiya, H. Takeda, M. M. Rajabali

RUTHERFORD CENTENNIAL CONFERENCE ON NUCLEAR PHYSICS, 2011 381 2012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

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

QUADRUPOLE MOMENT OF THE 7/2(1) ISOMER STATE OF S-43M 査読

R. Chevrier, J. M. Daugas, L. Gaudefroy, Y. Ichikawa, H. Ueno, M. Hass, H. Haas, S. Cottenier, N. Aoi, K. Asahi, D. L. Balabanski, N. Fukuda, T. Furukawa, G. Georgiev, H. Hayashi, H. Iijima, N. Inabe, T. Inoue, M. Ishihara, Y. Ishii, D. Kameda, T. Kubo, T. Nanao, G. Neyens, T. Ohnishi, M. M. Rajabali, K. Suzuki, H. Takeda, M. Tsuchiya, N. Vermeulen, H. Watanabe, A. Yoshimi

PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON EXOTIC NUCLEI (EXON 2012) 59 - 66 2012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：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.

Development of longitudinal-gradient magnet for time focusing of ultra-cold neutron with anisotropic inter-pole 査読

Yasushi Arimoto, Yoshihisa Iwashita, Tamaki Yoshioka, Masaaki Kitaguchi, Sohei Imajo, Hirohiko M. Shimizu, Koichiro Asahi, Takashi Ino, Yoshio Kamiya, Kenji Mishima, Suguru Muto, Kenji Sakai, Tatsushi Shima, Kaoru Taketani, Satoru Yamashita, Akihiro Yoshimi

IEEE Transactions on Applied Superconductivity 22 ( 3 ) 2012年

掲載種別：研究論文（学術雑誌）

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

Frequency characteristics of a nuclear spin maser for the search for the electric dipole moment of Xe-129 atom 査読

T. Inoue, M. Tsuchiya, T. Furukawa, H. Hayashi, T. Nanao, A. Yoshimi, M. Uchida, Y. Matsuo, K. Asahi

PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES 43 ( 3 ) 847 - 850 2011年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Development of high-sensitivity NMOR magnetometry for an EDM experiment 査読

T. Nanao, A. Yoshimi, T. Inoue, T. Furukawa, M. Tsuchiya, H. Hayashi, M. Uchida, K. Asahi

INTERNATIONAL NUCLEAR PHYSICS CONFERENCE 2010 (INPC): STANDARD MODEL TESTS AND FUNDAMENTAL SYMMETRIES 312 2011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

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

Magnetic Field Stabilization for (129)Xe EDM Search Experiment 査読

Takeshi Furukawa, Takeshi Inoue, Tsubasa Nanao, Akihiro Yoshimi, Masato Tsuchiya, Hironori Hayashi, Makoto Uchida, Koichiro Asahi

INTERNATIONAL NUCLEAR PHYSICS CONFERENCE 2010 (INPC): STANDARD MODEL TESTS AND FUNDAMENTAL SYMMETRIES 312 2011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

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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