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Journal Articles

Level structures of $$^{56,58}$$Ca cast doubt on a doubly magic $$^{60}$$Ca

Chen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.

Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08

https://doi.org/10.1016/j.physletb.2023.138025
 Times Cited Count：1 Percentile：0.02(Astronomy & Astrophysics)

Gamma decays were observed in $$^{56}$$Ca and $$^{58}$$Ca following quasi-free one-proton knockout reactions from $$^{57,59}$$Sc. For $$^{56}$$Ca, a $$gamma$$ ray transition was measured to be 1456(12) keV, while for $$^{58}$$Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the $$2^{+}_{1} rightarrow 0^{+}_{gs}$$ decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for $$2^{+}_{1}$$ level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the $$0_{f5/2}$$ and $$0_{g9/2}$$ orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic $$^{60}$$Ca and potentially drives the dripline of Ca isotopes to $$^{70}$$Ca or even beyond.

Journal Articles

"Southwestern" boundary of the $$N = 40$$ island of inversion; First study of low-lying bound excited states in $$^{59}$$V and $$^{61}$$V

Elekes, Z.*; Juh$'a$sz, M. M.*; Sohler, D.*; Sieja, K.*; Yoshida, Kazuki; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; Baba, Hidetada*; et al.

Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12

https://doi.org/10.1103/PhysRevC.106.064321
 Times Cited Count：2 Percentile：0.02(Physics, Nuclear)

The low-lying level structure of $$^{59}$$V and $$^{61}$$V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for $$^{61}$$V while the neutron knock-out reaction provided the data for $$^{59}$$V. Four and five new transitions were determined for $$^{59}$$V and $$^{61}$$V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed $$gamma$$ rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2$$^{-}$$ and 9/2$$^{-}$$ levels. The ($$p$$,$$p'$$) excitation cross sections for $$^{61}$$V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, $$^{61}$$V could not be unambiguously placed on the island of inversion.

Journal Articles

Extended $$p_{3/2}$$ neutron orbital and the $$N = 32$$ shell closure in $$^{52}$$Ca

Enciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; et al.

Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12

https://doi.org/10.1103/PhysRevLett.129.262501
 Times Cited Count：4 Percentile：46.35(Physics, Multidisciplinary)

The one-neutron knockout from $$^{52}$$Ca was performed at $$sim$$230 MeV/nucleon combined with prompt $$gamma$$ spectroscopy. The momentum distributions corresponding to the removal of $$1f_{7/2}$$ and $$2p_{3/2}$$ neutrons were measured. The cross sections are consistent with a shell closure at the neutron number $$N = 32$$, found as strong as at $$N = 28$$ and $$N = 34$$ in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron $$1_{f7/2}$$ and $$2p_{3/2}$$ orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the $$2p_{3/2}$$ orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.

Journal Articles

A First glimpse at the shell structure beyond $$^{54}$$Ca; Spectroscopy of $$^{55}$$K, $$^{55}$$Ca, and $$^{57}$$Ca

Koiwai, Takuma*; Wimmer, K.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Duguet, T.*; Holt, J. D.*; Miyagi, Takayuki*; Navr$'a$til, P.*; Ogata, Kazuyuki*; et al.

Physics Letters B, 827, p.136953_1 - 136953_7, 2022/04

https://doi.org/10.1016/j.physletb.2022.136953
 Times Cited Count：4 Percentile：52.69(Astronomy & Astrophysics)

no abstracts in English

Journal Articles

Investigation of the ground-state spin inversion in the neutron-rich $$^{47,49}$$Cl isotopes

Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; G$'o$mez-Ramos, M.*; et al.

Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10

AA2021-0468.pdf:1.29MB

https://doi.org/10.1103/PhysRevC.104.044331
 Times Cited Count：5 Percentile：46.8(Physics, Nuclear)

no abstracts in English

Journal Articles

Pairing forces govern population of doubly magic $$^{54}$$Ca from direct reactions

Browne, F.*; Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Ogata, Kazuyuki*; Utsuno, Yutaka; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; Calvet, D.*; et al.

Physical Review Letters, 126(25), p.252501_1 - 252501_7, 2021/06

https://doi.org/10.1103/PhysRevLett.126.252501
 Times Cited Count：10 Percentile：69.3(Physics, Multidisciplinary)

Direct proton-knockout reactions of $$^{55}$$Sc were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of $$^{54}$$Ca were investigated through $$gamma$$-ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological inter-nucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of $$^{55}$$Sc, valence proton removals populated predominantly the ground-state of $$^{54}$$Ca. This counter-intuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.

Journal Articles

First spectroscopic study of $$^{51}$$Ar by the ($$p$$,2$$p$$) reaction

Juh$'a$sz, M. M.*; Elekes, Z.*; Sohler, D.*; Utsuno, Yutaka; Yoshida, Kazuki; Otsuka, Takaharu*; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Baba, Hidetada*; et al.

Physics Letters B, 814, p.136108_1 - 136108_8, 2021/03

AA2020-0747.pdf:0.83MB

https://doi.org/10.1016/j.physletb.2021.136108
 Times Cited Count：5 Percentile：46.8(Astronomy & Astrophysics)

The nuclear structure of $$^{51}$$Ar was studied by the ($$p$$,2$$p$$) reaction using $$gamma$$-ray spectroscopy for the bound and unbound states. Comparing the results to our shell-model calculations, two bound and six unbound states were established. The low cross sections populating the two bound states of $$^{51}$$Ar could be interpreted as a clear signature for the presence of significant sub-shell closures at neutron numbers 32 and 34 in argon isotopes.

Journal Articles

Shell evolution of $$N$$ = 40 isotones towards $$^{60}$$Ca; First spectroscopy of $$^{62}$$Ti

Cort$'e$s, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Lenzi, S. M.*; Men$'e$ndez, J.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; et al.

Physics Letters B, 800, p.135071_1 - 135071_7, 2020/01

https://doi.org/10.1016/j.physletb.2019.135071
 Times Cited Count：31 Percentile：96.23(Astronomy & Astrophysics)

Excited states in the $$N$$ = 40 isotone $$^{62}$$Ti were populated via the $$^{63}$$V($$p$$,$$2p$$)$$^{62}$$Ti reaction at $$sim$$200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using $$gamma$$-ray spectroscopy. The energies of the $$2_1^+ rightarrow 0_{rm gs}^+$$ and $$4_1^+ rightarrow 2_1^+$$ transitions, observed here for the first time, indicate a deformed Ti ground state. These energies are increased compared to the neighboring $$^{64}$$Cr and $$^{66}$$Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings.

Journal Articles

Quasifree neutron knockout from $$^{54}$$Ca corroborates arising $$N=34$$ neutron magic number

Chen, S.*; Lee, J.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Chazono, Yoshiki*; Navr$'a$til, P.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Raimondi, F.*; et al.

Physical Review Letters, 123(14), p.142501_1 - 142501_7, 2019/10

AA2019-0306.pdf:0.57MB

https://doi.org/10.1103/PhysRevLett.123.142501
 Times Cited Count：47 Percentile：92.65(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Thermal behavior, structure, dynamic properties of aqueous glycine solutions confined in mesoporous silica MCM-41 investigated by X-ray diffraction and quasi-elastic neutron scattering

Yoshida, Koji*; Inoue, Takuya*; Torigoe, Motokatsu*; Yamada, Takeshi*; Shibata, Kaoru; Yamaguchi, Toshio*

Journal of Chemical Physics, 149(12), p.124502_1 - 124502_10, 2018/09

https://doi.org/10.1063/1.5039892
 Times Cited Count：4 Percentile：17.83(Chemistry, Physical)

Differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering (QENS) measurements of aqueous glycine solutions confined in mesoporous silica (MCM-41) were performed at different glycine concentrations, pH, and loading ratio (= mass of glycine solution / mass of dry MCM-41) in the temperature range from 305 to 180 K to discuss the confinement effect on the thermal behavior, the structure, and the dynamic properties of the solutions.

Journal Articles

Evaluation for the configurational and electronic state of SO$$_{3}$$ adsorbed on Pt surface

Suzuki, Chikashi; Yamada, Yoichi; Nakagiri, Toshio

Applied Surface Science, 256(3), p.862 - 869, 2009/11

https://doi.org/10.1016/j.apsusc.2009.08.078
 Times Cited Count：8 Percentile：36.66(Chemistry, Physical)

no abstracts in English

Journal Articles

An Integration scheme of boundary elements for meshfree finite element analysis with structured grid

Yamada, Tomonori; Nagashima, Toshio*

Nihon Keisan Kogakkai Rombunshu (Internet), 2009(6), 7 Pages, 2009/03

http://joi.jlc.jst.go.jp/JST.JSTAGE/jsces/2009.20090006

An integration scheme for finite elements on the boundary of analysis domain in structured finite element analysis is proposed in this paper. In structured finite element analysis, the structured grid is adopted as finite elements and the inconsistency between boundary of finite elements and that of analysis domain occurs. In this paper, Newton-Cotes integration technique with sub-cell evaluation of integration region is proposed and efficient integration of element stiffness matrices on the boundary of analysis domain is achieved.

JAEA Reports

Evaluation technology for burnup and generated amount of plutonium by measurement of xenon isotopic ratio in dissolver off-gas at reprocessing facility (Joint research)

Okano, Masanori; Kuno, Takehiko; Takahashi, Ichiro*; Shirozu, Hidetomo; Charlton, W. S.*; Wells, C. A.*; Hemberger, P. H.*; Yamada, Keiji; Sakai, Toshio

JAEA-Technology 2006-055, 38 Pages, 2006/12

JAEA-Technology-2006-055.pdf:3.33MB

The amount of Pu in the spent fuel was evaluated from Xe isotopic ratio in off-gas in reprocessing facility, is related to burnup. Six batches of dissolver off-gas at spent fuel dissolution process were sampled from the main stack in Tokai Reprocessing Plant during BWR fuel reprocessing campaign. Xenon isotopic ratio was determined with GC/MS. Burnup and generated amount of Pu were evaluated with Noble Gas Environmental Monitoring Application code (NOVA), developed by Los Alamos National Laboratory. Inferred burnup evaluated by Xe isotopic measurements and NOVA were in good agreement with those of the declared burnup in the range from -3.8% to 7.1%. Also, the inferred amount of Pu in spent fuel was in good agreed with those of the declared amount of Pu calculated by ORIGEN code in the range from -0.9% to 4.7%. The evaluation technique is applicable for both burnup credit to achieve efficient criticality safety control and a new measurement method for safeguards inspection.

JAEA Reports

A Development of a database system for the released radioactive gases and liquid from the nuclear facilities

Kikuchi, Masamitsu; Taki, Mitsumasa; Kume, Etsuo; Kobayashi, Hideo*; Yamada, Toshio*; Yamaguchi, Takenori

JAERI-Data/Code 2004-006, 146 Pages, 2004/03

JAERI-Data-Code-2004-006.pdf:6.87MB

The nuclear facilities, which are required to control the released radioactive gases and liquid, exist in Tokai research establishment as much as 40. These radioactive controls are carried out complying with the statutes in each facility. The released radioactivity data of each facility must be reported to MEXT and Ibaraki Prefecture from Tokai Research Establishment. This system is developed to make the database gathering the radioactivity data of each facilities for unitary control as Tokai Research Establishment and contribute to make the reports to MEXT and Ibaraki Prefecture.

Journal Articles

Progress on design and R&D of ITER FW/blanket

Ioki, Kimihiro*; Akiba, Masato; Cardella, A.*; Daenner, W.*; Elio, F.*; Enoeda, Mikio; Lorenzetto, P.*; Miki, Nobuharu*; Osaki, Toshio*; Rozov, V.*; et al.

Fusion Engineering and Design, 61-62, p.399 - 405, 2002/11

https://doi.org/10.1016/S0920-3796(02)00109-6
 Times Cited Count：11 Percentile：58.11(Nuclear Science & Technology)

We report progress on the ITER-FEAT Blanket design and R&D during 2001-2002. Four major sub-components (FW, shield body, flexible support and electrical connection) have been highlighted. Regarding the FW, design on a separate FW panel concept has progressed, and heat load tests on a small-scale mock-up have been successfully performed with 0.7 MW/m$$^{2}$$, 13000 cycles. Full-scale separate FW panels (dimensions: 0.9$$times$$0.25$$times$$0.07 m) have been fabricated by HIPing and brazing. Regarding the shield body, a radial flow cooling design has been developed, and full-scale partial mock-ups have been fabricated by using water-jet cutting. A separate FW panel was assembled with one the shield body mock-ups. Regarding the flexible support, mill-annealed Ti (easier fabricability) alloy has been selected, and the remote assembly has been considered in the design. In mechanical tests, the requires buckling strength and mechanical fatigue characteristics have been confirmed. Regarding the electrical connection, one-body structure design without welding joints has been developed. Mechanical fatigue tests in the 3 directions, have been carried out, and thermal fatigue tests and electrical tests in a solenoidal magnetic field have been performed. Feasibility of the design has been confirmed. Through progress on design and R&D of the blanket, cost reduction has been achieved, and feasibility of design and fabricability of the components have been confirmed.

JAEA Reports

Development of fabrication technologies for ITER in-vessel components

Kuroda, Toshimasa*; Sato, Kazuyoshi; Akiba, Masato; Ezato, Koichiro; Enoeda, Mikio; Osaki, Toshio*; Kosaku, Yasuo; Sato, Satoshi; Sato, Shinichi*; Suzuki, Satoshi*; et al.

JAERI-Tech 2002-044, 25 Pages, 2002/03

JAERI-Tech-2002-044.pdf:2.68MB

no abstracts in English

JAEA Reports

Physics design of advanced steady-state tokamak reactor A-SSTR 2

Nishio, Satoshi; Ushigusa, Kenkichi; Ueda, Shuzo; Polevoi, A.*; Kurita, Genichi; Tobita, Kenji; Kurihara, Ryoichi; Hu, G.; Okada, Hidetoshi*; Murakami, Yoshiki*; et al.

JAERI-Research 2000-029, 105 Pages, 2000/10

JAERI-Research-2000-029.pdf:4.19MB

no abstracts in English

Journal Articles

Dynamic response of base isolation test system for nuclear components under natural seismic motion

Tsutsumi, Hideaki*; Yamada, Hiroyuki; Teragaki, Toshio*; Ebisawa, Katsumi; Shibata, Katsuyuki

Seismic Engineering 2000 (PVP-Vol.402-1), p.141 - 146, 2000/00

no abstracts in English

Oral presentation

Determination of neptunium of Tokai reprocessing plant; Determination of neptunium by $$gamma$$ spectrometry in nitric acid media

Kitao, Takahiko; Nemoto, Hirokazu*; Yamada, Keiji; Sakai, Toshio

no journal, , 

no abstracts in English

Oral presentation

Determination of neptunium in Tokai reprocessing plant; Determination of neptunium by $$gamma$$ spectrometry in nitric acid media

Kitao, Takahiko; Nemoto, Hirokazu*; Yamada, Keiji; Sakai, Toshio

no journal, , 

no abstracts in English

34 (Records 1-20 displayed on this page)