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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:0 Percentile:100(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

Proton-induced deuteron knockout reaction as a probe of an isoscalar proton-neutron pair in nuclei

Chazono, Yoshiki*; Yoshida, Kenichi*; Yoshida, Kazuki; Ogata, Kazuyuki*

Physical Review C, 103(2), p.024609_1 - 024609_7, 2021/02

 Times Cited Count:0 Percentile:100(Physics, Nuclear)

The isoscalar $$pn$$ pair is expected to emerge in nuclei. We aim to clarify the correspondence between the $$pn$$ pairing strength in many-body calculation and the cross section of proton-induced deuteron knockout ($$p$$, $$pd$$) reaction on $$^{16}$$O. The radial wave function of the isoscalar $$pn$$ pair with respect to the center of $$^{16}$$O is calculated with the energy density functional (EDF) approach and is implemented in the distorted wave impulse approximation framework. The $$pn$$ pairing strength $$V_0$$ in the EDF calculation is varied and the corresponding change in the cross section is investigated. A clear $$V_0$$ dependence of the cross section is found. The nuclear distortion is found to make the $$V_0$$ dependence stronger. Because of the clear $$V_0$$-coross section correspondence, the ($$p$$, $$pd$$) reaction will be a promising probe for the isoscalar $$pn$$ pair in nuclei. For quantitative discussion, further modification of the description of the reaction process will be necessary.

Journal Articles

Quasifree neutron knockout reaction reveals a small $$s$$-Orbital component in the Borromean nucleus $$^{17}$$B

Yang, 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:0 Percentile:100(Physics, Multidisciplinary)

A quasifree ($$p$$,$$pn$$) experiment was performed to study the structure of the Borromean nucleus $$^{17}$$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 $$1s_{1/2}$$ and $$0d_{5/2}$$ orbitals, and a surprisingly small percentage of 9(2)% was determined for $$1s_{1/2}$$. Our finding of such a small $$1s_{1/2}$$ 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 $$^{17}$$B. The present work gives the smallest $$s$$- or $$p$$-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of $$s$$ or $$p$$ orbitals is not a prerequisite for the occurrence of a neutron halo.

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:0 Percentile:100(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

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:7 Percentile:3.25(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

 Times Cited Count:16 Percentile:7.08(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Experimental study of Gamow-Teller transitions via the high-energy-resolution $$^{18}$$O($$^3$$He,$$t$$)$$^{18}$$F reaction; Identification of the low-energy "super" -Gamow-Teller state

Fujita, Hirohiko*; Fujita, Yoshitaka*; Utsuno, Yutaka; Yoshida, Kenichi*; Adachi, Tatsuya*; Algora, A.*; Csatl$'o$s, M.*; Deaven, J. M.*; Estevez-Aguado, E.*; Guess, C. J.*; et al.

Physical Review C, 100(3), p.034618_1 - 034618_13, 2019/09

 Times Cited Count:2 Percentile:52.25(Physics, Nuclear)

no abstracts in English

Journal Articles

Observation of a Be double-Lambda hypernucleus in the J-PARC E07 experiment

Ekawa, Hiroyuki; Ashikaga, Sakiko; Hasegawa, Shoichi; Hashimoto, Tadashi; Hayakawa, Shuhei; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi; Kimbara, Shinji*; Nanamura, Takuya; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.021D02_1 - 021D02_11, 2019/02

 Times Cited Count:8 Percentile:28.48(Physics, Multidisciplinary)

Journal Articles

Nuclear structure of $$^{76}$$Ni from the ($$p$$,$$2p$$) reaction

Elekes, Z.*; Kripk$'o$, $'A$*; 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:5 Percentile:28.91(Physics, Nuclear)

The nuclear structure of the $$^{76}$$Ni nucleus was investigated by ($$p$$,$$2p$$) reaction using a NaI(Tl) array to detect the deexciting prompt $$gamma$$ rays. A new transition with an energy of 2227 keV was identified by $$gamma gamma$$ and $$gamma gamma gamma$$ 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.

Journal Articles

Coupled analysis of fuel debris distribution and recriticality by both multiphase/multicomponent flow and continuous energy neutron transport Monte Carlo simulations

Yamashita, Susumu; Tada, Kenichi; Yoshida, Hiroyuki; Suyama, Kenya

Nippon Genshiryoku Gakkai Wabun Rombunshi, 17(3/4), p.99 - 105, 2018/12

In order to reveal melt relocation behaviors of core internals phenomenologically and to reduce the uncertainties of the melt relocation analysis in existing SA analysis codes, in JAEA, the numerical simulation code for melt relocation and accumulation behaviors based on computational fluid dynamics named JUPITER has been developed. In this paper, to consider the estimation method for fuel debris composition and its re-criticality, we performed the melt accumulating and spreading simulation to the pedestal region by JUPITER and also performed re-criticality analysis by Monte Carlo Codes for Neutron Transport Calculations based on Continuous Energy and Multi-group Methods (MVP) using detailed fuel debris composition data obtained by JUPITER. From the coupled analysis on fuel debris distribution by JUPITER and MVP, we had prospects for a detailed possibility of re-criticality of fuel debris with detailed fuel debris distribution.

Journal Articles

Network system operation for J-PARC accelerators

Kamikubota, Norihiko*; Yamada, Shuei*; Sato, Kenichiro*; Kikuzawa, Nobuhiro; Yamamoto, Noboru*; Yoshida, Susumu*; Nemoto, Hiroyuki*

Proceedings of 16th International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS 2017) (Internet), p.1470 - 1473, 2018/01

no abstracts in English

Journal Articles

New precise measurement of muonium hyperfine structure interval at J-PARC

Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11

 Times Cited Count:3 Percentile:8.56

Journal Articles

New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

 Times Cited Count:6 Percentile:6.07

Journal Articles

Present status of TIARA at JAEA

Yuyama, Takahiro; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Ishizaka, Tomohisa; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Miyawaki, Nobumasa; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.302 - 304, 2015/09

no abstracts in English

Journal Articles

Model magnet development of D1 beam separation dipole for the HL-LHC upgrade

Nakamoto, Tatsushi*; Sugano, Michinaka*; Xu, Q.*; Kawamata, Hiroshi*; Enomoto, Shun*; Higashi, Norio*; Idesaki, Akira; Iio, Masami*; Ikemoto, Yukio*; Iwasaki, Ruri*; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4000505_1 - 4000505_5, 2015/06

 Times Cited Count:0 Percentile:100(Engineering, Electrical & Electronic)

Recently, development of superconducting magnet system with high radiation resistance has been demanded for application in accelerator facilities such as CERN LHC. In order to realize superconducting magnet system with high radiation resistance, it is necessary to develop electrical insulator with high radiation resistance because the electrical insulator is made of organic materials whose radiation resistance is inferior to that of inorganic materials. We developed a glass fiber reinforced plastic with bismaleimide-triazine resin. The developed material showed excellent radiation resistance; the material evolved gases of 5$$times$$10 $$^{-5}$$mol/g and maintained flexural strength of 640MPa (90% of initial value).

Journal Articles

Formation of a uniform ion beam based on nonlinear focusing and its applications at the JAEA TIARA cyclotron

Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Yoshida, Kenichi; Ishibori, Ikuo; Okumura, Susumu

Proceedings of 6th International Particle Accelerator Conference (IPAC '15) (Internet), p.236 - 238, 2015/06

JAEA Reports

Development of microbeam formation and single-ion hit technologies at the TIARA cyclotron

Yokota, Wataru; Sato, Takahiro; Kamiya, Tomihiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Funayama, Tomoo; Sakashita, Tetsuya; et al.

JAEA-Technology 2014-018, 103 Pages, 2014/09

JAEA-Technology-2014-018.pdf:123.66MB

The world's first microbeam focusing technology for heavy ions of hundreds MeV accelerated by a cyclotron has been developed at the TIARA facility in the Takasaki Advanced Radiation Research Institute of the Japan Atomic Energy Agency. The technology enables us to form a microbeam of less than 1 $$mu$$m in diameter and to shoot a specified point on a target by one ion (single-ion hit) with spatial accuracy of microbeam size. In the course of the development, a cyclotron technology to accelerate a small energy-spread beam of hundres MeV, which is necessary for focusing to 1 $$mu$$m, has been developed as well as a beam focusing apparatus, beam size measurement and so forth based on the several-MeV microbeam/single-ion hit system of the TIARA electrostatic accelerators. Applicability of the technologies was examined by actual use in irradiation experiment and the result were fed back to them. This paper reports the process and the results of the development over ten years.

Journal Articles

Formation of large-area heavy-ion uniform beams using multipole magnets in TIARA, JAEA

Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Yoshida, Kenichi; Ishibori, Ikuo; Okumura, Susumu

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.138 - 142, 2014/06

no abstracts in English

Journal Articles

Analysis of phase bunching in AVF cyclotron

Miyawaki, Nobumasa; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Yoshida, Kenichi; Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Ishibori, Ikuo; Nara, Takayuki

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 158, 2014/03

Journal Articles

Fast single-ion hit system for heavy-ion microbeam at TIARA cyclotron, 6

Yokota, Wataru; Sato, Takahiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Koka, Masashi; Yokoyama, Akihito; Kada, Wataru*; et al.

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 160, 2014/03

no abstracts in English

174 (Records 1-20 displayed on this page)