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Wrzosek-Lipska, K.*; Rezynkina, K.*; Bree, N.*; Zieliska, M.*; Gaffney, L. P.*; Petts, A.*; Andreyev, A. N.; Bastin, B.*; Bender, M.*; Blazhev, A.*; et al.
European Physical Journal A, 55(8), p.130_1 - 130_23, 2019/08
被引用回数:16 パーセンタイル:80.08(Physics, Nuclear)The neutron-deficient mercury isotopes serve as a classical example of shape coexistence, whereby at low energy near-degenerate nuclear states characterized by different shapes appear. The electromagnetic structure of even-mass Hg isotopes was studied using safe-energy Coulomb excitation of neutron-deficient mercury beams delivered by the REX-ISOLDE facility at CERN. The population of 0
, 2
, and 4
states was observed in all nuclei under study. Reduced
matrix elements coupling populated yrast and non-yrast states were extracted, including their relative signs. These are a sensitive probe of shape coexistence and may be used to validate nuclear models. The experimental results are discussed in terms of mixing of two different configurations and are compared with three different model calculations: the Beyond Mean Field model, the Interacting Boson Model with configuration mixing and the General Bohr Hamiltonian. Partial agreement with experiment was observed, hinting to missing ingredients in the theoretical descriptions.
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:22 パーセンタイル:78.29(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.
Gaffney, L. P.*; Robinson, A. P.*; Jenkins, D. G.*; Andreyev, A. N.; Bender, M.*; Blazhev, A.*; Bree, N.*; Bruyneel, B.*; Butler, P.*; Cocolios, T. E.*; et al.
Physical Review C, 91(6), p.064313_1 - 064313_11, 2015/06
被引用回数:11 パーセンタイル:55.72(Physics, Nuclear)Radioactive ion beams of Rn were studied by means of low-energy Coulomb excitation at REX-ISOLDE, CERN. The electric-quadrupole (E2) matrix elements connecting the first excited 2
to the ground state of these nuclei was extracted, which permits to determine the collectivity of these isotopes, which in both cases is deduced to be weak, as expected from the low-lying level-energy scheme. Comparisons were also made with beyond-mean-field model calculations and the magnitude of the transitional quadrupole moments are well reproduced.
Diriken, J.*; Patronis, N.*; Andreyev, A. N.; Antalic, S.*; Bildstein, V.*; Blazhev, A.*; Darby, I. G.*; De Witte, H.*; Eberth, J.*; Elseviers, J.*; et al.
Physical Review C, 91(5), p.054321_1 - 054321_15, 2015/05
被引用回数:10 パーセンタイル:52.68(Physics, Nuclear)Excited states up to an excitation energy of 5.8 MeV were populated in the neutron-rich isotope Ni via the
Ni(d,p) transfer reaction at REX-Isolde, CERN. In particular, single-neutron states above the N=40 sub-shell gap were populated, and the relative spectroscopic factors were extracted using distorted-wave Born approximation analysis. The positive parity g
, d
and s
neutron orbits above the shell closure are assumed to induce strong quadrupole collectivity in neutron-rich Fe and Cr isotopes. The extracted relative spectroscopic factors show that the strength of the d
orbit is mostly split over two states, hinting to substantial mixing of the neutron d
configuration with collective modes of the core. The size of the N=50 shell gap was also estimated, and found to be 2.6 MeV near
Ni, as also determined in lighter Ni isotopes.
Orlandi, R.; Mcher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; et al.
Physics Letters B, 740, p.298 - 302, 2015/01
被引用回数:28 パーセンタイル:84.14(Astronomy & Astrophysics)Single-neutron states in Zn have been populated using the reaction
Zn(d,p) at REX-Isolde, CERN. The analysis reveals that the lowest excited states in
Zn lie at approximately 1 MeV, and involve neutron orbits above the N=50 shell gap. A 5/2
configuration was assigned to the 983-keV state. Comparison with large-scale shell model calculations supports a robust neutron N=50 shell closure for
Ni. These data constitute an important step towards the understanding the magicity of
Ni and the structure of nuclei in the region.
Diriken, J.*; Patronis, N.*; Andreyev, A. N.*; Antalic, S.*; Bildstein, V.*; Blazhev, A.*; Darby, I. G.*; De Witte, H.*; Eberth, J.*; Elseviers, J.*; et al.
Physics Letters B, 736, p.533 - 538, 2014/09
被引用回数:19 パーセンタイル:72.93(Astronomy & Astrophysics)The neutron orbits , d
and s
are assumed to be responsible for the swift onset of collectivity observed in the region below
Ni. In order to gather information on the single-particle energies and spectroscopic factors of these orbitals, single-particle states in the nucleus
Ni were populated using the reaction
Ni(d,p), in inverse kinematics, at REX-ISOLDE, CERN. The new isotope was studied using combined particle-
spectroscopy. Comparison with DWBA calculations, permitted the identification of positive parity states with a substantial amount of
d
(1007 keV) and
d
(2207 and 3277 keV) single-particle strength. Comparisons with extended Shell-Model calculations was also performed to confirm the single-particle nature of these states, and to deduce general properties around
Ni.
Illana, A.*; Jungclaus, A.*; Orlandi, R.; Perea, A.*; Bauer, C.*; Briz, J. A.*; Egido, J. L.*; Gernhuser, R.*; Leske, J.*; M
cher, D.*; et al.
Physical Review C, 89(5), p.054316_1 - 054316_11, 2014/05
被引用回数:11 パーセンタイル:58.53(Physics, Nuclear)The factor of the first excited state in
Zn was measured using the transient-field technique in combination with Coulomb excitation. The experiment was ran at REX-ISOLDE, CERN, and the
-ray perturbed angular correlations were measured using 4 triple Germanium clusters of the Miniball array. The experimental result
(2
) = +0.47(14) is significant to establish the structure of the Zn isotopes near N=40. Comparison with shell-model calculations reveal that to reproduce the measured energies and B(E2) of the Zn isotopes around N=40, both the proton excitations from the
orbit and neutron excitations into the
and
orbits are essential. Furthermore, beyond-mean-field calculations reveal the need to include the triaxial degree of freedom.
Orlandi, R.; Mcher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; et al.
no journal, ,
Single-neutron states in the = 49 isotope
Zn were populated in the
Zn(d,p)
Zn transfer reaction at REX-ISOLDE, CERN. The combined detection of protons ejected in the reaction and of
rays emitted by
Zn permitted the identification of the lowest-lying 5/2
and 1/2
excited states. The analysis of proton angular distributions links these states to a significant amount of single-particle strength around 1 MeV, and specifically to the
d
and
s
neutron orbits, which lie above the
= 50 neutron shell gap. Comparison with large-scale-shell-model calculations supports a robust
= 50 shell-closure for
Ni. These data constitute a considerable step towards the understanding of the magicity of
Ni and of the structure of isotopes in the region.