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Iwamoto, Osamu; Iwamoto, Nobuyuki; Kunieda, Satoshi; Minato, Futoshi; Nakayama, Shinsuke; Abe, Yutaka*; Tsubakihara, Kosuke*; Okumura, Shin*; Ishizuka, Chikako*; Yoshida, Tadashi*; et al.
Journal of Nuclear Science and Technology, 60(1), p.1 - 60, 2023/01
Times Cited Count：6 Percentile：98.58(Nuclear Science & Technology)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：27 Percentile：97(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
-Orbital component in the Borromean nucleus 
BYang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.
Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02
Times Cited Count：29 Percentile：96.61(Physics, Multidisciplinary)A quasifree (
,
) experiment was performed to study the structure of the Borromean nucleus B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 
and 
orbitals, and a surprisingly small percentage of 9(2)% was determined for . Our finding of such a small component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in B. The present work gives the smallest - or -orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of or orbitals is not a prerequisite for the occurrence of a neutron halo.
Nagae, Daisuke*; Abe, Yasushi*; Okada, Shunsuke*; Omika, Shuichiro*; Wakayama, Kiyoshi*; Hosoi, Shun*; Suzuki, Shinji*; Moriguchi, Tetsuro*; Amano, Masamichi*; Kamioka, Daiki*; et al.
Nuclear Instruments and Methods in Physics Research A, 986, p.164713_1 - 164713_7, 2021/01
Times Cited Count：4 Percentile：72.51(Instruments & Instrumentation)
F from 
O
?Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.
Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05
Times Cited Count：13 Percentile：78.47(Physics, Multidisciplinary)The structure of a neutron-rich F nucleus is investigated by a quasifree (
) knockout reaction. The sum of spectroscopic factors of 
orbital is found to be 1.0 
0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 
35% O
, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.
CoLokotko, T.*; Leblond, S.*; Lee, J.*; Doornenbal, P.*; Obertelli, A.*; Poves, A.*; Nowacki, F.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Authelet, G.*; et al.
Physical Review C, 101(3), p.034314_1 - 034314_7, 2020/03
Times Cited Count：7 Percentile：73.84(Physics, Nuclear)The structures of the neutron-rich Co isotopes were investigated via () knockout reactions at the Radioactive Isotope Beam Factory, RIKEN. Level schemes were reconstructed using the 
coincidence technique, with tentative spin-parity assignments based on the measured inclusive and exclusive cross sections. Comparison with shell-model calculations suggests coexistence of spherical and deformed shapes at low excitation energies in the Co isotopes.
Ni from the (,
) reactionElekes, Z.*; Kripk
, 
*; Sohler, D.*; Sieja, K.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Doornenbal, P.*; Obertelli, A.*; Authelet, G.*; Baba, Hidetada*; et al.
Physical Review C, 99(1), p.014312_1 - 014312_7, 2019/01
Times Cited Count：7 Percentile：65.88(Physics, Nuclear)The nuclear structure of the Ni nucleus was investigated by (,) reaction using a NaI(Tl) array to detect the deexciting prompt 
rays. A new transition with an energy of 2227 keV was identified by 
and 
coincidences. Our shell-model calculations using the Lenzi, Nowacki, Poves, and Sieja interaction produced good candidates for the experimental proton hole states in the observed energy region, and the theoretical cross sections showed good agreement with the experimental values. Although we could not assign all the experimental states to the theoretical ones unambiguously, the results are consistent with a reasonably large Z = 28 shell gap for nickel isotopes in accordance with previous studies.
Zr determination with isotope dilution ICP-MSAsai, Shiho; Hanzawa, Yukiko; Konda, Miki; Suzuki, Daisuke; Magara, Masaaki; Kimura, Takaumi; Ishihara, Ryo*; Saito, Kyoichi*; Yamada, Shinsuke*; Hirota, Hideyuki*
Talanta, 185, p.98 - 105, 2018/08
Times Cited Count：7 Percentile：31.96(Chemistry, Analytical)Estimating the risks associated with radiation from long-lived fission products (LLFP) in radioactive waste is essential to ensure the long-term safety of potential disposal sites. In this study, the amount of Zr, a LLFP, was determined by ICP-MS after separating Zr from a spent nuclear fuel solution using a microvolume anion-exchange cartridge (TEDA cartridge). The TEDA cartridge achieved highly selective separation of Zr regardless of its small bed volume of 0.08 cm
. The time taken to complete the Zr separation was 1.2 min with a flow rate of 1.5 mL/min, which was 10 times faster than that for a conventional anion-exchange resin column. Almost all the other elements were removed, leading to accurate measurement of Zr. The result connects experimental value to theoretical prediction provided by ORIGEN2, which requires verification. With the measured value, we demonstrated that the theoretical value is reliable enough to estimate radiation risks.
Np content in spent nuclear fuelAsai, Shiho; Hanzawa, Yukiko; Konda, Miki; Suzuki, Daisuke; Magara, Masaaki; Kimura, Takaumi; Ishihara, Ryo*; Saito, Kyoichi*; Yamada, Shinsuke*; Hirota, Hideyuki*
Analytical Chemistry, 88(6), p.3149 - 3155, 2016/03
Times Cited Count：8 Percentile：32.25(Chemistry, Analytical)Neptunium-237 (Np) is one of the major long-lived radionuclides found in spent nuclear fuel. To evaluate the long-term safety of a HLW repository, the Np content in spent nuclear fuel must be determined. In this study, micro-volume anion-exchange porous polymer disk-packed cartridges were prepared for Am-Np separation, which is required prior to the measurement of Np with ICP-MS. Disks with a volume of 0.08 cm were cut out from porous sheets having triethylenediamine (TEDA)-containing polymer chains densely attached on the pore surface. The resulting TEDA-introduced disk cartridge was applied to a spent nuclear fuel sample. The chemical yield of Np was 90.4%, which is sufficiently high for ICP-MS measurement of Np. Compared with the conventional separation technique using commercially available anion-exchange resin columns, the time required to adsorb, wash and elute Np using the TEDA-introduced disk cartridge was reduced by 75%.
SGo, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Kobayashi, Motoki*; Kisamori, Keiichi*; Takaki, Motonobu*; Miya, Hiroyuki*; Ota, Shinsuke*; Michimasa, Shinichiro*; Shimoura, Susumu*; et al.
JPS Conference Proceedings (Internet), 6, p.030005_1 - 030005_4, 2015/06
Tanaka, Ryota*; Ishihara, Ryo*; Miyoshi, Kazuyoshi*; Umeno, Daisuke*; Saito, Kyoichi*; Asai, Shiho; Yamada, Shinsuke*; Hirota, Hideyuki*
Separation Science and Technology, 49(1), p.154 - 159, 2014/01
Times Cited Count：4 Percentile：16.71(Chemistry, Multidisciplinary)Uchiyama, Shoichiro*; Ishihara, Ryo*; Umeno, Daisuke*; Saito, Kyoichi*; Yamada, Shinsuke*; Hirota, Hideyuki*; Asai, Shiho
Journal of Chemical Engineering of Japan, 46(6), p.414 - 419, 2013/06
Times Cited Count：7 Percentile：27.4(Engineering, Chemical)Wada, Go*; Ishihara, Ryo*; Miyoshi, Kazuyoshi*; Umeno, Daisuke*; Saito, Kyoichi*; Asai, Shiho; Yamada, Shinsuke*; Hirota, Hideyuki*
Solvent Extraction and Ion Exchange, 31(2), p.210 - 220, 2013/02
Times Cited Count：2 Percentile：10.68(Chemistry, Multidisciplinary)A crosslinked chelating porous sheet was prepared by cografting ethylene glycol dimethacrylate (EGDMA) with glycidyl methacrylate onto an electron-beam-irradiated porous polyethylene sheet, followed by the introduction of an iminodiacetate group. At a molar percentage of EGDMA of 1.0 mol%, the sheet exhibited a maximum dynamic binding capacity for copper ions of 0.93 mmol/g, while the equilibrium binding capacity remained the same (1.2 mmol/g) as that of a non-crosslinked chelating porous sheet. The crosslinking of the grafted chain causes copper ions to lower their diffusion rate along the sheet thickness driven by the gradient of the amount of copper ions adsorbed.
Z nucleus, 
Ar and high-spin states in A = 30 40 nucleiIdeguchi, Eiji*; Ota, Shinsuke*; Morikawa, Tsuneyasu*; Oshima, Masumi; Koizumi, Mitsuo; Toh, Yosuke; Kimura, Atsushi; Harada, Hideo; Furutaka, Kazuyoshi; Nakamura, Shoji; et al.
Progress of Theoretical Physics Supplement, (196), p.427 - 432, 2012/10
Ishihara, Ryo*; Asai, Shiho; Otosaka, Shigeyoshi; Yamada, Shinsuke*; Hirota, Hideyuki*; Miyoshi, Kazuyoshi*; Umeno, Daisuke*; Saito, Kyoichi*
Solvent Extraction and Ion Exchange, 30(2), p.171 - 180, 2012/02
Times Cited Count：8 Percentile：30.85(Chemistry, Multidisciplinary)Osaka, Masahiko; Konashi, Kenji*; Hayashi, Hirokazu; Li, D.*; Homma, Yoshiya*; Yamamura, Tomoo*; Sato, Isamu; Miwa, Shuhei; Sekimoto, Shun*; Kubota, Takumi*; et al.
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
Summer schools for future experts have successfully been completed under Japan Actinide Network (J-ACTINET) for the purpose of development of human resources who are expected to be engaged in every areas of actinide-research/engineering. The first summer school was held in Ibaraki-area in August 2009, followed by the second one in Kansai-area in August 2010. Two summer schools have focused on actual experiences of actinides in actinide-research fields for university students and young researchers/engineers as an introductory course of actinide-researches. Several quasi actinide-handling experiences at the actinide-research fields have attracted attentions of participants at the first school in Ibaraki-area. The actual experiments using actinides-containing solutions have been carried out at the second school in Kansai-area. Future summer schools will be held every year for the sustainable human resource development in various actinide-research fields.
Wada, Go*; Ishihara, Ryo*; Miyoshi, Kazuyoshi*; Umeno, Daisuke*; Saito, Kyoichi*; Asai, Shiho; Yamada, Shinsuke*; Hirota, Hideyuki*
Nihon Ion Kokan Gakkai-Shi, 22(2), p.47 - 52, 2011/01
no abstracts in English
-octylphosphine oxide, and its adsorption/elution of bismuth ionsTanaka, Ryota*; Ishihara, Ryo*; Miyoshi, Kazuyoshi*; Umeno, Daisuke*; Saito, Kyoichi*; Asai, Shiho; Yamada, Shinsuke*; Hirota, Hideyuki*
Reactive and Functional Polymers, 70(12), p.986 - 990, 2010/12
Times Cited Count：7 Percentile：29.88(Chemistry, Applied)Asai, Shiho; Kimura, Takaumi; Miyoshi, Kazuyoshi*; Saito, Kyoichi*; Yamada, Shinsuke*; Hirota, Hideyuki*
Nihon Ion Kokan Gakkai-Shi, 21(3), p.334 - 339, 2010/07
nucleus ArIdeguchi, Eiji*; Ota, Shinsuke*; Morikawa, Tsuneyasu*; Oshima, Masumi; Koizumi, Mitsuo; Toh, Yosuke; Kimura, Atsushi; Harada, Hideo; Furutaka, Kazuyoshi; Nakamura, Shoji; et al.
Physics Letters B, 686(1), p.18 - 22, 2010/03
Times Cited Count：32 Percentile：85.57(Astronomy & Astrophysics)A rotational band with five -ray transitions ranging from 2
to 12 states was identified in Ar. The deduced transition quadrupole moment of 1.45 0.15 eb indicates that the band has a superdeformed shape. The nature of the band is revealed by cranked Hartee Fock Bogoliubov calculations and a multiparticle-multihole configuration is assigned to the band.
