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Kaya, L.*; Vogt, A.*; Reiter, P.*; Siciliano, M.*; 清水 則孝*; 宇都野 穣; Wang, H.-K.*; Gargano, A.*; Coraggio, L.*; Itaco, N.*; et al.
Physical Review C, 100(2), p.024323_1 - 024323_18, 2019/08
被引用回数:10 パーセンタイル:73.81(Physics, Nuclear)Baの高スピン状態を
および
反応によって生成し、そこからの脱励起ガンマ線を観測した。
Baの1942keVのアイソマーの寿命を66.6(20)nsと決定し、
Baの
よりの高スピン状態を見つけた。この結果を殻模型計算と比較し、
Baの
と
の間隔や
と
の間隔が広がるなどの特徴が計算によってよく再現できることがわかった。
Jentschel, M.*; Blanc, A.*; de France, G.*; Kster, U.*; Leoni, S.*; Mutti, P.*; Simpson, G.*; Soldner, T.*; Ur, C.*; Urban, W.*; et al.
Journal of Instrumentation (Internet), 12(11), p.P11003_1 - P11003_33, 2017/11
被引用回数:33 パーセンタイル:84.86(Instruments & Instrumentation)A highly efficient array of high-purity germanium (HPGe) detectors was developed and operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of -rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 10
ns
cm
at the target position and negligible neutron halo. The target was surrounded by an array of eight to ten anti-Compton shielded EXOGAM Clover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr
:(Ce) detectors from the FATIMA collaboration.
Morales, A. I.*; Benzoni, G.*; Watanabe, H.*; 角田 佑介*; Otsuka, T.*; 西村 俊二*; Browne, F.*; Daido, R.*; Doornenbal, P.*; Fang, Y.*; et al.
Physics Letters B, 765, p.328 - 333, 2017/02
被引用回数:31 パーセンタイル:92.58(Astronomy & Astrophysics)The level schemes of neutron-rich isotopes Co and
Ni were populated in the
decay of
Fe and studied using
-delayed
-ray spectroscopy of the
decay, at the RIBF in RIKEN, Japan. The experimental results were compared to state-of-the-art shell-model calculations, and indicate a dominance of prolate deformation in the low-lying states, coexisting with spherical states. The
decay of the
isobars is shown to progress in accordance to a new type of shell evolution, the so-called Type II, which involves many particle-hole excitations across energy gaps.
Morales, A. I.*; Benzoni, G.*; Watanabe, H.*; 西村 俊二*; Browne, F.*; Daido, R.*; Doornenbal, P.*; Fang, Y.*; Lorusso, G.*; Patel, Z.*; et al.
Physical Review C, 93(3), p.034328_1 - 034328_14, 2016/03
被引用回数:25 パーセンタイル:86.72(Physics, Nuclear)Low-lying excited states in Ni have been investigated at RIKEN by studying the
decay of
Co to
Ni.
Co was separated with BigRIPS, implanted into the WaS3ABi Silicon array, and the
ray measured using the EURICA
spectrometer. From the analysis, 60 new
-ray transitions and 21 new levels in
Ni were observed. The new experimental information is compared to shell-model calculations which include neutron excitation across the
shell. The calculations reproduce rather well the observed states, implying that a clear understanding of these low-lying excitations has been achieved.
Benzoni, G.*; Morales, A. I.*; Watanabe, H.*; 西村 俊二*; Coraggio, L.*; Itaco, N.*; Gargano, A.*; Browne, F.*; Daido, R.*; Doornenbal, P.*; et al.
Physics Letters B, 751, p.107 - 112, 2015/12
被引用回数:20 パーセンタイル:79.94(Astronomy & Astrophysics)The decays of
Mn have been measured at the RIBF facility at RIKEN using the EURICA
spectrometer combined with an active stopper consisting of a stack of Si detectors. Half-lives and
-delayed neutron emission probabilities have been extracted for these decays, together with first experimental information on excited states populated in
Fe. The data indicate a continuously increasing deformation for Fe isotopes up to A=70, and interpreted to be due to the interplay between quadrupole correlation of specific neutron orbitals and the monopole component of the proton-neutron interaction.
Bottoni, S.*; Leoni, S.*; Fornal, B.*; Raabe, R.*; Rusek, K.*; Benzoni, G.*; Bracco, A.*; Crespi, F. C. L.*; Morales, A. I.*; Bednarczyk, P.*; et al.
Physical Review C, 92(2), p.024322_1 - 024322_8, 2015/08
被引用回数:19 パーセンタイル:78.42(Physics, Nuclear)An exploratory experiment was performed at REX-ISOLDE CERN to test the potential of cluster-transfer reactions at the Coulomb barrier as a mechanism to explore the structure of exotic neutron-rich nuclei. The transfer of triton and alpha particles in a reaction of a beam of Rb onto a
Li target were studied through particle-
coincidence measurements. The results indicate that such cluster transfer reactions can be an efficient method to investigate the structure of neutron-rich nuclei at medium-high excitation energies and spins.
Lorusso, G.*; 西村 俊二*; Xu, Z. Y.*; Jungclaus, A.*; Shimizu, Y.*; Simpson, G. S.*; Sderstr
m, P.-A.*; Watanabe, H.*; Browne, F.*; Doornenbal, P.*; et al.
Physical Review Letters, 114(19), p.192501_1 - 192501_7, 2015/05
被引用回数:142 パーセンタイル:97.88(Physics, Multidisciplinary)The -decay half-lives of 110 neutron-rich isotopes of the elements from Rb to Sn were measured at the RIBF Facility at RIKEN, Japan. The new data demonstrate the persistence of shell structure far from stability and have direct implications for the
-process calculations. In particular, the new half-lives have a global impact on the calculated
-process elemental abundances, and alleviate the underproduction of isotopes just above and below the A=130 peak, which in the past required the introduction of shell structure modifications. Reaction-network calculations based on the new data reinforce the notion that the r-process abundance pattern may result from the freeze-out of a (n,
)
(
,n) equilibrium.
Watanabe, H.*; Lorusso, G.*; 西村 俊二*; Otsuka, T.*; Ogawa, K.*; Xu, Z. Y.*; 炭竃 聡之*; Sderstr
m, P.-A.*; Doornenbal, P.*; Li, Z.*; et al.
Physical Review Letters, 113(4), p.042502_1 - 042502_6, 2014/07
被引用回数:24 パーセンタイル:78.09(Physics, Multidisciplinary)A new isomer with a half-life of 23.0(8) ms has been identified in Pd at 2406 keV excitation. The proposed spin and parity configuration is 10
, with maximally aligned configuration of two
neutron hole.
-decay from the long-lived isomer was also observed to populated excited states at high spins in
Ag. The small energy difference between the 10
and 7
isomers in
Pd was interpreted in the frame of the monopole shift of the 1
neutron orbit. The effects of the monopole interaction on the evolution of single-neutron energies below
Sn are discussed in terms of central and tensor forces.
Doornenbal, P.*; Reiter, P.*; Grawe, H.*; 大塚 孝治*; Al-Khatib, A.*; Banu, A.*; Beck, T.*; Becker, F.*; Bednarczyk, P.*; Benzoni, G.*; et al.
Physics Letters B, 647(4), p.237 - 242, 2007/04
被引用回数:31 パーセンタイル:85.71(Astronomy & Astrophysics)ドイツ重イオン研究所(GSI)でCaの第一励起状態
からの脱励起
線を初めて測定した。その励起エネルギーは、3015(16)keVであることがわかり、鏡像核である
Sの励起エネルギーよりも276keVも低いことがわかった。殻模型により理論的にこれら両者の構造を調べたところ、
殻を仮定した模型空間でよく説明されることがわかった。この鏡像核の大きなエネルギーのずれは、クーロン力によるトーマスエルマン効果であると考えられ、それを現象論的に取り入れた殻模型計算によりこの領域のミラー核のエネルギーシフトがよく説明されることがわかった。