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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

 Times Cited Count:0

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

 Times Cited Count:1 Percentile:46.35(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

 Times Cited Count:1 Percentile:0(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

 Times Cited Count:1 Percentile:46.35(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

$$N$$ = 32 shell closure below calcium; Low-lying structure of $$^{50}$$Ar

Cort$'e$s, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Men$'e$ndez, J.*; Ogata, Kazuyuki*; Schwenk, A.*; Shimizu, Noritaka*; Simonis, J.*; et al.

Physical Review C, 102(6), p.064320_1 - 064320_9, 2020/12

 Times Cited Count:4 Percentile:65.18(Physics, Nuclear)

Low-lying excited states in the $$N$$ = 32 isotope $$^{50}$$Ar were investigated by in-beam $$gamma$$-ray spectroscopy following proton- and neutron-knockout, multinucleon removal, and proton inelastic scattering at the RIKEN Radioactive Isotope Beam Factory. The energies of the two previously reported transitions have been confirmed, and five additional states are presented for the first time, including a candidate for a 3$$^{-}$$ state. The level scheme built using $$gamma$$ $$gamma$$ coincidences was compared to shell-model calculations in the $$sd-pf$$ model space and to ${it ab initio}$ predictions based on chiral two- and three-nucleon interactions. Theoretical proton- and neutron-knockout cross sections suggest that two of the new transitions correspond to 2$$^{+}$$ states, while the previously proposed 4$$^{+}_{1}$$ state could also correspond to a 2$$^{+}$$ state.

Journal Articles

Clades of huge phages from across Earth's ecosystems

Al-Shayeb, B.*; Sachdeva, R.*; Chen, L.-X.*; Ward, F.*; Munk, P.*; Devoto, A.*; Castelle, C. J.*; Olm, M. R.*; Bouma-Gregson, K.*; Amano, Yuki; et al.

Nature, 578(7795), p.425 - 431, 2020/02

 Times Cited Count:126 Percentile:99.56(Multidisciplinary Sciences)

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

 Times Cited Count:19 Percentile:96.74(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

Fine structure in the $$alpha$$ decay of $$^{223}$$U

Sun, M. D.*; Liu, Z.*; Huang, T. H.*; Zhang, W. Q.*; Andreyev, A. N.; Ding, B.*; Wang, J. G.*; Liu, X. Y.*; Lu, H. Y.*; Hou, D. S.*; et al.

Physics Letters B, 800, p.135096_1 - 135096_5, 2020/01

 Times Cited Count:7 Percentile:85.65(Astronomy & Astrophysics)

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

 Times Cited Count:32 Percentile:93.02(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Investigation of the electronic structure and lattice dynamics of the thermoelectric material Na-doped SnSe

Wu, P.*; Zhang, B.*; Peng, K. L.*; Hagiwara, Masayuki*; Ishikawa, Yoshihisa*; Kofu, Maiko; Lee, S. H.*; Kumigashira, Hiroshi*; Hu, C. S.*; Qi, Z. M.*; et al.

Physical Review B, 98(9), p.094305_1 - 094305_7, 2018/09

 Times Cited Count:6 Percentile:38.8(Materials Science, Multidisciplinary)

Using angle-resolved photoemission spectroscopy and inelastic neutron scattering, we have studied how electronic structures and lattice dynamics evolve with temperature in Na-doped SnSe.

Journal Articles

Effect of topsoil removal and selective countermeasures on radiocesium accumulation in rice plants in Fukushima paddy field

Yang, B.*; Onda, Yuichi*; Omori, Yoshihiro*; Sekimoto, Hitoshi*; Fujiwara, Toru*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya; Takahashi, Junko*; Sun, X.*

Science of the Total Environment, 603-604, p.49 - 56, 2017/12

 Times Cited Count:1 Percentile:4.64(Environmental Sciences)

Journal Articles

Experimental study on interfacial area transport of two-phase bubbly flow in a vertical large-diameter square duct

Shen, X.*; Sun, Haomin; Deng, B.*; Hibiki, Takashi*; Nakamura, Hideo

International Journal of Heat and Fluid Flow, 67(Part A), p.168 - 184, 2017/10

 Times Cited Count:12 Percentile:62.29(Thermodynamics)

An experimental study on upward bubbly air-water flows in a vertical large-diameter square duct have been performed by mainly using four-sensor probes. Local measurements of interfacial area concentration (IAC), void fraction, 3D bubble velocity vector and bubble diameter at 3 axial positions were conducted. Although the interfacial area transport equation (IATE) and its bubble coalescence and breakup models have already played an important role in predicting the IAC in general two-phase flow fields, they are mainly developed based on the two-phase flow experimental data taken in round pipes or small diameter channels. To confirm their usability in large-diameter square duct, this study has evaluated the 1D one-group IATE with its 6 sets of bubble coalescence and breakup models with the presently-obtained database. It was found the relative error between the best prediction and the database was 25%.

Journal Articles

Axial flow characteristics of bubbly flow in a vertical large-diameter square duct

Shen, X.*; Sun, Haomin; Deng, B.*; Hibiki, Takashi*; Nakamura, Hideo

Proceedings of 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) (USB Flash Drive), 14 Pages, 2017/09

An experimental study on the upward bubbly air-water flows in a vertical large-diameter square duct have been performed by using four-sensor probes. The four-sensor probe were applied in the local measurements at 3 axial positions along the flow direction to obtain interfacial area concentration, 3-D bubble velocity vector and bubble diameter. The obtained void fraction, interfacial area concentration, 3-D bubble velocity vector and bubble diameter provided valuable insight into the flow structure and will serve as a valuable database to develop the mechanistic models for interfacial area transport equation sources and sinks.

Journal Articles

Gas-liquid bubbly flow structure in a vertical large-diameter square duct

Shen, X.*; Sun, Haomin; Deng, B.*; Hibiki, Takashi*; Nakamura, Hideo

Progress in Nuclear Energy, 89, p.140 - 158, 2016/05

 Times Cited Count:15 Percentile:86.34(Nuclear Science & Technology)

An experimental study was performed on the local structure of upward air-water two-phase flow in a vertical large diameter square duct by using a four-sensor probe. The four-sensor probe method classifying spherical and non-spherical bubbles was applied as a key measurement way to obtain local parameters such as 3-D bubble velocity vector, bubble diameter and interfacial area concentration. Both the local void fraction and interfacial area concentration indicated radial core-peak and wall-peak distributions at low and high liquid flow rates respectively. The 2 components of the bubble velocity vector in the cross-section revealed that there exists a rotating secondary flow in the octant symmetric triangular area and the magnitude of the rotating secondary flow increases with the liquid flow rate. Some of constitutive correlations of drift-flux model and interfacial area concentration are reviewed to study their predictabilities against the present data.

Journal Articles

Neutron spectroscopic factors of $$^{55}$$Ni hole-states from (p,d) transfer reactions

Sanetullaev, A.*; Tsang, M. B.*; Lynch, W. G.*; Lee, J.*; Bazin, D.*; Chan, K. P.*; Coupland, D.*; Hanzl, V.*; Hanzlova, D.*; Kilburn, M.*; et al.

Physics Letters B, 736, p.137 - 141, 2014/09

 Times Cited Count:12 Percentile:66.06(Astronomy & Astrophysics)

no abstracts in English

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:8 Percentile:51.82(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Structure of $$^{33}$$Mg sheds new light on the $$N$$=20 island of inversion

Kanungo, R.*; Nociforo, C.*; Prochazka, A.*; Utsuno, Yutaka; Aumann, T.*; Boutin, D.*; Cortina-Gil, D.*; Davids, B.*; Diakaki, M.*; Farinon, F.*; et al.

Physics Letters B, 685(4-5), p.253 - 257, 2010/05

 Times Cited Count:35 Percentile:87.73(Astronomy & Astrophysics)

no abstracts in English

Journal Articles

One-neutron removal measurement reveals $$^{24}$$O as a new doubly magic nucleus

Kanungo, R.*; Nociforo, C.*; Prochazka, A.*; Aumann, T.*; Boutin, D.*; Cortina-Gil, D.*; Davids, B.*; Diakaki, M.*; Farinon, F.*; Geissel, H.*; et al.

Physical Review Letters, 102(15), p.152501_1 - 152501_4, 2009/04

 Times Cited Count:153 Percentile:96.74(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Neutron-proton pairing competition in $$N=Z$$ nuclei; Metastable state decays in the proton dripline nuclei $$^{82}_{41}$$Nb and $$^{86}_{43}$$Tc

Garnsworthy, A. B.*; Regan, P. H.*; C$'a$ceres, L.*; Pietri, S.*; Sun, Y.*; Rudolph, D.*; G$'o$rska, M.*; Podoly$'a$k, Z.*; Steer, S. J.*; Hoischen, R.*; et al.

Physics Letters B, 660(4), p.326 - 330, 2008/02

 Times Cited Count:25 Percentile:80.25(Astronomy & Astrophysics)

The low-lying structures of the self-conjugate ($$N=Z$$) nuclei $$^{82}_{41}$$Nb and $$^{86}_{43}$$Tc have been investigated using isomeric-decay spectroscopy following the projectile fragmentation of a $$^{107}$$Ag beam. These represent the heaviest odd-odd $$N=Z$$ nuclei in which internal decays have been identified to date. The resulting level schemes shed light on the shape evolution along the $$N=Z$$ line between the doubly-magic systems $$^{56}_{28}$$Ni and $$^{100}_{50}$$Sn and support a preference for $$T=1$$ states in $$T_z=0$$ odd-odd nuclei at low excitation energies associated with a $$T=1$$ neutron-proton pairing gap. Comparison with Projected Shell Model calculations suggests that the decay in $$^{82}$$Nb may be interpreted as an isospin-changing $$K$$ isomer.

Oral presentation

Observation of the signal increase for electrochemical devices placed near PWR and intense tritium source

Suda, Shoya*; Ishibashi, Kenji*; Lee, E.*; Shigyo, Nobuhiro*; Ikeda, Nobuo*; Sun, G. M.*; Han, B.-Y.*; Takada, Hiroshi; Harada, Masahide

no journal, , 

Our group has experience to carry out the experiment with small electrochemical devices at heavy-water-moderated Advanced Thermal Reactor (ATR, FUGEN), and observed a clear signal increase near the reactor core. The present study is aiming at demonstrating the response of the electrochemical device to tritium amount. The experiments were performed at (1) Pressurized right Water Reactor (PWR, tritium amount of 30 g and a great quantity of beta emitters) at a distance of 26 m from the core, and (2) Tritium Process Laboratory of Japan Atomic Energy Agency (TPL, tritium amount ~10 g) at a position of 8.6 m from the source. Signal increase was observed in both measurements. Analysis made clear that the detector signal is ascribed to the amount of low-energy beta emitters of plutonium 241 and tritium in the PWR experiment while it is attributed to the quantity of tritium in the TPL measurement.

22 (Records 1-20 displayed on this page)