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S Sakaguchi,
Y. Iseri,
T Uesaka,
M. Tanifuji,
K. Amos,
N. Aoi, Y Hashimoto,
E Hiyama,
M Ichikawa,
Y Ichikawa, [......],
K Sekiguchi,
M Shinohara,
K Suda,
D Suzuki,
Y Takahashi,
A. Tamii,
T. Wakui,
K. Yako,
M Yamaguchi,
Y Yamamoto
[show abstract]
[hide abstract]
ABSTRACT: The vector analyzing power has been measured for the elastic scattering of
neutron-rich 6He from polarized protons at 71 MeV/nucleon making use of a newly
constructed solid polarized proton target operated in a low magnetic field and
at high temperature. Two approaches based on local one-body potentials were
applied to investigate the spin-orbit interaction between a proton and a 6He
nucleus. An optical model analysis revealed that the spin-orbit potential for
6He is characterized by a shallow and long-ranged shape compared with the
global systematics of stable nuclei. A semimicroscopic analysis with a
alpha+n+n cluster folding model suggests that the interaction between a proton
and the alpha core is essentially important in describing the p+6He elastic
scattering. The data are also compared with fully microscopic analyses using
non-local optical potentials based on nucleon-nucleon g-matrices.
06/2011;
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Y. Satou,
T. Nakamura,
Y. Kondo,
N. Matsui, Y. Hashimoto,
T. Nakabayashi,
T. Okumura,
M. Shinohara,
N. Fukuda,
T. Sugimoto, [......],
M. Ishihara,
S. Kawai,
H.J. Ong,
T.K. Onishi,
S. Shimoura,
M. Tamaki,
T. Kobayashi,
Y. Matsuda,
N. Endo,
M. Kitayama
[show abstract]
[hide abstract]
ABSTRACT: A Gamow–Teller (GT) transition from the drip-line nucleus 14Be to 14B was studied via the (p,n) reaction in inverse kinematics using a secondary 14Be beam at 69 MeV/nucleon. The invariant mass method is employed to reconstruct the energy spectrum. A peak is observed at an excitation energy of 1.27(2) MeV in 14B, together with bumps at 2.08 and 4.06(5) MeV. The observed forward peaking of the state at 1.27 MeV and a good description for the differential cross section, obtained with a DWBA calculation provide support for the 1+ assignment to this state. By extrapolating the cross section to zero momentum transfer the GT-transition strength is deduced. The value is found to compare well with that reported in a β-delayed neutron emission study.
Physics Letters B. 02/2011;
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T Uesaka,
S Sakaguchi,
Y. Iseri,
K. Amos,
N. Aoi, Y Hashimoto,
E Hiyama,
M Ichikawa,
Y Ichikawa,
S Ishikawa, [......],
M Shinohara,
K Suda,
D Suzuki,
Y Takahashi,
M. Tanifuji,
A. Tamii,
T. Wakui,
K. Yako,
Y Yamamoto,
M Yamaguchi
[show abstract]
[hide abstract]
ABSTRACT: Vector analyzing power for the proton-6He elastic scattering at 71 MeV/nucleon has been measured for the first time, with a newly developed polarized proton solid target working at low magnetic field of 0.09 T. The results are found to be incompatible with a t-matrix folding model prediction. Comparisons of the data with g-matrix folding analyses clearly show that the vector analyzing power is sensitive to the nuclear structure model used in the reaction analysis. The alpha-core distribution in 6He is suggested to be a possible key to understand the nuclear structure sensitivity. Comment: 5 pages, 3 figures, accepted for publication as a Rapid Communication in Physical Review C
07/2010;
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N Aoi,
E Takeshita,
H Suzuki,
S Takeuchi,
S Ota,
H Baba,
S Bishop,
T Fukui, Y Hashimoto,
H J Ong, [......],
T K Ohnishi,
H Sakurai,
S Shimoura,
R Sugo,
D Suzuki,
M K Suzuki,
M Tamaki,
K Tanaka,
Y Togano,
K Yamada
[show abstract]
[hide abstract]
ABSTRACT: The structure of neutron-rich isotopes 60Cr and 62Cr was studied via proton inelastic scattering in inverse kinematics. The deformation lengths (delta) for 60Cr and 62Cr were extracted as 1.12(16) and 1.36(14) fm, respectively, providing evidence for enhanced collectivity in these nuclei. An excited state at 1180(10) keV in 62Cr was identified for the first time. We adopted 4;{+} as its spin and parity, leading to the rapid increase of the Ex(4;{+})/E_{x}(2;{+}) ratio, which indicates the development of large deformation in 62Cr near N=40. Importance of the admixture of the gd-shell component above N=40 is also discussed by comparing with a modern shell model calculation.
Physical Review Letters 02/2009; 102(1):012502. · 7.37 Impact Factor
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Y. Kondo,
T. Nakamura,
Y. Satou,
T. Matsumoto,
N. Aoi,
N. Endo,
N. Fukuda,
T. Gomi, Y. Hashimoto,
M. Ishihara, [......],
T. K. Onishi,
H. Otsu,
H. Sakurai,
S. Shimoura,
M. Shinohara,
T. Sugimoto,
S. Takeuchi,
M. Tamaki,
Y. Togano,
Y. Yanagisawa
[show abstract]
[hide abstract]
ABSTRACT: We have studied the one-neutron removal reactions of 18C at 81 MeV/nucleon and 19C at 68 MeV/nucleon on a liquid hydrogen target. Transverse-momentum distributions of the core fragments 17C and 18C, and their partial cross sections, are measured using coincidences with the γ rays. These are compared to theoretical calculations based on the continuum-discretized coupled-channels (CDCC) method. We have found that the transverse-momentum distributions of 17C are well described by the CDCC calculations, and the agreement provides evidence for the spin-parity assignments of Jπ=1/2+ for the 0.21-MeV state and Jπ=5/2+ for the 0.33-MeV state in 17C. The Jπ=(2,3)+ assignment for the 4.0-MeV state in 18C is obtained for the first time based on the momentum distribution of 18C. The measured partial cross sections are consistent with the CDCC calculations combined with shell-model spectroscopic factors. The present study demonstrates that the transverse-momentum distribution obtained in a one-neutron removal reaction on a proton target is as useful as the conventional longitudinal-momentum distribution measured with the heavier Be or C targets for determining the orbital angular momentum of a removed neutron.
Phys. Rev. C. 01/2009; 79(1).
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N Aoi,
E Takeshita,
H Suzuki,
S Takeuchi,
S Ota,
H Baba,
S Bishop,
T Fukui, Y Hashimoto,
H J Ong, [......],
T K Ohnishi,
H Sakurai,
S Shimoura,
R Sugo,
D Suzuki,
M K Suzuki,
M Tamaki,
K Tanaka,
Y Togano,
K Yamada
[show abstract]
[hide abstract]
ABSTRACT: The structure of neutron-rich isotopes Cr-60 and Cr-62 was studied via proton inelastic scattering in inverse kinematics. The deformation lengths (delta) for Cr-60 and Cr-62 were extracted as 1.12(16) and 1.36 (14) fm, respectively, providing evidence for enhanced collectivity in these nuclei. An excited state at 1180(10) keV in Cr-62 was identified for the first time. We adopted 4(+) as its spin and parity, leading to the rapid increase of the E-x(4(+))/E-x(2(+)) ratio, which indicates the development of large deformation in Cr-62 near N = 40. Importance of the admixture of the gd-shell component above N = 40 is also discussed by comparing with a modern shell model calculation.
Physical Review Letters 01/2009; 102(1). · 7.37 Impact Factor
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Y. Satou,
T. Nakamura,
N. Fukuda,
T. Sugimoto,
Y. Kondo,
N. Matsui, Y. Hashimoto,
T. Nakabayashi,
T. Okumura,
M. Shinohara, [......],
H.J. Ong,
T.K. Onishi,
S. Shimoura,
M. Tamaki,
T. Kobayashi,
H. Otsu,
Y. Matsuda,
N. Endo,
M. Kitayama,
M. Ishihara
[show abstract]
[hide abstract]
ABSTRACT: The neutron-rich carbon isotopes 19,17C have been investigated via proton inelastic scattering on a liquid hydrogen target at 70 MeV/nucleon. The invariant mass method in inverse kinematics was employed to reconstruct the energy spectrum, in which fast neutrons and charged fragments were detected in coincidence using a neutron hodoscope and a dipole magnet system. A peak has been observed with an excitation energy of 1.46(10) MeV in 19C, while three peaks with energies of 2.20(3), 3.05(3), and 6.13(9) MeV have been observed in 17C. Deduced cross sections are compared with microscopic DWBA calculations based on p-sd shell model wave functions and modern nucleon–nucleus optical potentials. Jπ assignments are made for the four observed states as well as the ground states of both nuclei.
Physics Letters B. 01/2008;
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N Aoi,
H Suzuki,
E Takeshita,
S Takeuchi,
S Ota,
H Baba,
S Bishop,
T Fukui, Y Hashimoto,
H J Ong, [......],
T K Ohnishi,
H Sakurai,
S Shimoura,
R Sugo,
D Suzuki,
M K Suzuki,
M Tamaki,
K Tanaka,
Y Togano,
K Yamada
Nucl.Phys. 01/2008; A805:400c.
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Z Elekes,
Zs Dombrádi,
N Aoi,
S Bishop,
Zs Fülöp,
J Gibelin,
T Gomi, Y Hashimoto,
N Imai,
N Iwasa, [......],
H Sakurai,
Y Satou,
D Sohler,
T Sumikama,
D Suzuki,
M Suzuki,
H Takeda,
S Takeuchi,
Y Togano,
Y Yanagisawa
[show abstract]
[hide abstract]
ABSTRACT: Neutron single particle energies have been measured in 23O using the 22O(d,p)23O*-->22O+n process. The energies of the resonant states have been deduced to be 4.00(2) MeV and 5.30(4) MeV. The first excited state can be assigned to the nu d3/2 single particle state from a comparison with shell model calculations. The measured 4.0 MeV energy difference between the nu s1/2 and nu d3/2 states gives the size of the N=16 shell gap which is in agreement with the recent USD05 ("universal" sd from 2005) shell model calculation, and is large enough to explain the unbound nature of the oxygen isotopes heavier than A=24. The resonance detected at 5.3 MeV can be assigned to a state out of the sd shell model space. Its energy corresponds to a approximately 1.3 MeV sized N=20 shell gap, therefore, the N=20 shell closure disappears at Z=8 in agreement with Monte Carlo shell model calculations using SDPF-M interaction.
Physical Review Letters 03/2007; 98(10):102502. · 7.37 Impact Factor
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Z. Elekes,
Zs. Dombrádi,
N. Aoi,
S. Bishop,
Zs. Fülöp,
J. Gibelin,
T. Gomi, Y. Hashimoto,
N. Imai,
N. Iwasa, [......],
H. Sakurai,
Y. Satou,
D. Sohler,
T. Sumikama,
D. Suzuki,
M. Suzuki,
H. Takeda,
S. Takeuchi,
Y. Togano,
Y. Yanagisawa
[show abstract]
[hide abstract]
ABSTRACT: We have searched for valence neutron decoupling in 22O, a phenomenon recently observed in neutron-rich C, B, and lighter O nuclei. From the cross section of the (d,d'γ) reaction for the transition between the ground state and the first 2+ state of 22O, the neutron and proton deformation parameters have been deduced by distorted wave analysis using and reanalyzing the data of a previous Coulomb excitation measurement. The ratio of the neutron and proton multipole transition matrix elements Mn/Mp compared to the N/Z value has been derived to be around 1. This result indicates that the 22O isotope has small and similar neutron and proton deformations, which is consistent with N=14 shell closure. Thus, the concept of neutron decoupling does not hold for this nucleus.
Phys. Rev. C. 07/2006; 74(1).
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Z. Elekes,
Zs. Dombrádi,
S. Bishop,
Zs. Fülöp,
J. Gibelin,
T. Gomi, Y. Hashimoto,
N. Imai,
N. Iwasa,
H. Iwasaki, [......],
H. Sakurai,
Y. Satou,
D. Sohler,
T. Sumikama,
D. Suzuki,
M. Suzuki,
H. Takeda,
S. Takeuchi,
Y. Togano,
Y. Yanagisawa
[show abstract]
[hide abstract]
ABSTRACT: The paper reports on the test of the newly developed RIKEN-ATOMKI CsI(Tl) array. It is demonstrated that high-quality detectors
with excellent light collection efficiency and narrow resolution distribution could be produced. The setup has been commissioned
in the study of the reaction of 22O + CD2. In the present paper, we summarize the results mainly on the (d, d′) channel. From the cross section for the transition between the ground state and the first 2+ state, we could deduce the “matter” deformation parameter to be βM = 0.23±0.02 by distorted wave analysis. Comparing this data with previous measurements it can be concluded that 22O isotope has moderate and similar neutron and proton deformations.
European Physical Journal A 02/2006; 27:321-324. · 2.19 Impact Factor
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Z Elekes,
Zs. Dombradi,
N Aoi,
S Bishop,
Zs. Fulop,
J Gibelin,
T Gomi, Y Hashimoto,
N Imai,
N Iwasa, [......],
H Sakurai,
Y Satou,
D Sohler,
T Sumikama,
D Suzuki,
M Suzuki,
H Takeda,
S Takeuchi,
Y Togano,
Y Yanagisawa
Phys.Rev. C. 01/2006; 74:017306.
