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Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Shigyo, Nobuhiro*; Watanabe, Fusao*; Sakurai, Hiroki*; Arai, Yoichi*
Nuclear Instruments and Methods in Physics Research A, 637(1), p.149 - 157, 2011/05
Times Cited Count:6 Percentile:44.16(Instruments & Instrumentation)A dose and spectrum monitoring system applicable to neutrons, photons and muons over wide ranges of energy, designated as DARWIN, has been developed for radiological protection in high-energy accelerator facilities. The performance of the upgraded DARWIN was examined in various radiation fields, including an operational field in J-PARC. The experiments revealed that the dose rates and spectra measured by the upgraded DARWIN are quite reasonable, even in radiation fields with peak structures in terms of both spectrum and time variation. These results clearly demonstrate the usefulness of DARWIN for improving radiation safety in high-energy accelerator facilities.
Aoki, Yuji*; Higemoto, Wataru; Tsunashima, Yoshino*; Yonezawa, Yuki*; Sato, Koki*; Koda, Akihiro*; Ito, Takashi; Oishi, Kazuki; Heffner, R. H.; Kikuchi, Daisuke*; et al.
Physica B; Condensed Matter, 404(5-7), p.757 - 760, 2009/04
Times Cited Count:4 Percentile:21.31(Physics, Condensed Matter)Zero field (ZF) and transverse field (TF) muon spin relaxation and rotation (SR) study has been carried out in filled-skutterudite SmOsSb in order to investigate the magnetically robust heavy-fermion (HF) state and the weak ferromagnetic anomaly. A large-amplitude oscillating signal appears in the ZF-SR spectra at low temperatures, confirming that the weak ferromagnetic anomaly is an intrinsic bulk property. Analysis reveals that the weak ferromagnetic moment is carried by itinerant heavy quasiparticles.
Sato, Hideyuki*; Aoki, Yuji*; Kikuchi, Daisuke*; Sugawara, Hitoshi*; Higemoto, Wataru; Oishi, Kazuki; Ito, Takashi; Heffner, R. H.; Saha, S. R.*; Koda, Akihiro*; et al.
Physica B; Condensed Matter, 404(5-7), p.749 - 753, 2009/04
Times Cited Count:5 Percentile:25.54(Physics, Condensed Matter)Wide varieties of strongly correlated electron phenomena are performed on the stage of a filled skutterudite structure. Especially when one of the players contains a plural number of 4f electrons, the orbital degrees of freedom play a major role as a new type of nonmagnetic and/or weak-magnetic phenomena. Several examples found in Pr- and Sm-based filled skutterudites are introduced in relation to muon spin relaxation experiments.
Kuroiwa, Sogo*; Sato, Koki*; Koda, Akihiro*; Kadono, Ryosuke*; Oishi, Kazuki*; Higemoto, Wataru; Akimitsu, Jun*
Journal of Physics and Chemistry of Solids, 68(11), p.2124 - 2128, 2007/11
Times Cited Count:3 Percentile:17.85(Chemistry, Multidisciplinary)The vortex state defined by two characteristic length scales, magnetic penetration depth () and coherence length (), in a layered hexagonal superconductor CaAlSi was probed using muon spin rotation. From preliminary analysis using modified London model, we found that the in-plane increases with increasing magnetic field while inter-plane is almost independent of magnetic field. The presence of field-induced quasiparticle excitation manifested in the field dependence of suggests that CaAlSi has an anisotropic gap structure.
Higemoto, Wataru; Aoki, Yuji*; Oishi, Kazuki; Ito, Takashi; Heffner, R. H.; Saha, S. R.*; Koda, Akihiro*; Sato, Hideyuki*; Kadono, Ryosuke*; Kikuchi, Daisuke*; et al.
Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.620 - 622, 2007/03
no abstracts in English
Ishida, Kenji*; Higemoto, Wataru; Oishi, Kazuki; Koda, Akihiro*; Sato, Koki*; Kadono, Ryosuke*; Fujita, Masaki*; Yamada, Kazuyoshi*
Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.526 - 528, 2006/10
Kadono, Ryosuke*; Sato, Koki*; Koda, Akihiro*; Nagata, Takashi*; Furukawa, Hazuki*; Suzuki, Junichi; Matsuda, Masaaki; Oishi, Kazuki; Higemoto, Wataru; Kuroiwa, Sogo*; et al.
Physical Review B, 74(2), p.024513_1 - 024513_5, 2006/07
Times Cited Count:10 Percentile:44.41(Materials Science, Multidisciplinary)The response of vortex state to the magnetic field in NbSn is probed using muon spin rotation and small-angle neutron scattering. A transformation of vortex structure between hexagonal and squared lattice is observed over a relatively low field range of 2-3T. The gradual increase of the magnetic penetration depth with increasing field provides microscopic evidence for anisotropic (or multigapped) -wave pairing suggested by the Raman scattering experiment. This result renders need for careful examination on the difference of electronic properties between NbSn and VSi.
Sato, Koki*; Goko, Tatsuro*; Takeshita, Satoshi*; Hayashi, Yuko*; Arai, Juichiro*; Higemoto, Wataru; Nishiyama, Kusuo*; Nagamine, Kanetada*
Physica B; Condensed Matter, 374-375, p.40 - 43, 2006/03
Times Cited Count:4 Percentile:22.72(Physics, Condensed Matter)We have performed muon spin relaxation and resistivity measurements under high pressure in LaBaCuO with x=0.125 and 0.135. With increasing pressure, the superconducting critical temperature increases for both samples. Even by applying pressure, static magnetic order still exists. This result indicates the LTT structure is not always necessary for stabilizing the static magnetic order. However, the magnetic volume fraction estimated is reduced by applying pressure. The reduction of the magnetic volume fraction for x=0.125 is less than that for x=0.135. This means hole concentration is one of the important factors for the appearance of the static magnetic order.
Osakabe, Toyotaka; Yamauchi, Hiroki; Kuwahara, Keitaro*; Iwasa, Kazuaki*; Aoki, Yuji*; Sato, Hideyuki*; Kogi, Masafumi*
no journal, ,
no abstracts in English
Osakabe, Toyotaka; Yamauchi, Hiroki; Kuwahara, Keitaro*; Iwasa, Kazuaki*; Aoki, Yuji*; Sato, Hideyuki*; Kogi, Masafumi*
no journal, ,
no abstracts in English