| Records |
| Author |
AGATA Collaboration (Liu, X. et al); Gadea, A.; Jurado, M.; Domingo-Pardo, C.; Huyuk, T.; Perez-Vidal, R.M. |
| Title |
Evidence for spherical-oblate shape coexistence in Tc-87 |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
106 |
Issue |
3 |
Pages |
034304 - 6pp |
| Keywords |
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Abstract  |
Excited states in the neutron-deficient nucleus Tc-87 have been studied via the fusion-evaporation reaction 54Fe(36Ar, 2n1p) Tc-87 at 115 MeV beam energy. The AGATA gamma-ray spectrometer coupled to the DIAMANT, NEDA, and Neutron Wall detector arrays for light-particle detection was used to measure the prompt coincidence of gamma rays and light particles. Six transitions from the deexcitation of excited states belonging to a new band in Tc-87 were identified by comparing gamma-ray intensities in the spectra gated under different reaction channel selection conditions. The constructed level structure was compared with the shell model and total Routhian surface calculations. The results indicate that the new band structure in 87Tc is built on a spherical configuration, which is different from that assigned to the previously identified oblate yrast rotational band. |
| Address |
[Liu, X.; Cederwall, B.; Qi, C.; Wyss, R. A.; Aktas, O.; Ertoprak, A.; Zhang, W.; Nyberg, A. Atac; Back, T.] Royal Inst Technol, Dept Phys, S-10405 Stockholm, Sweden, Email: xiaoyuli@kth.se |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9985 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000863087400003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5373 |
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| Author |
Boso, A. et al; Domingo-Pardo, C.; Perez-Vidal, R.M. |
| Title |
Isospin dependence of electromagnetic transition strengths among an isobaric triplet |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
| Volume |
797 |
Issue |
|
Pages |
134835 - 6pp |
| Keywords |
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| Abstract |
Electric quadrupole matrix elements, M-p, for the J(pi) = 2(+) -> 0(+), Delta T = 0, T = 1 transitions across the A = 46 isobaric multiplet Cr-46-V-46-Ti-46 have been measured at GSI with the FRS-LYCCA-AGATA setup. This allows direct insight into the isospin purity of the states of interest by testing the linearity of M-p with respect to T-z. Pairs of nuclei in the T = 1 triplet were studied using identical reaction mechanisms in order to control systematic errors. The M-p values were obtained with two different methodologies: (i) a relativistic Coulomb excitation experiment was performed for Cr-46 and Ti-46; (ii) a “stretched target” technique was adopted here, for the first time, for lifetime measurements in V-46 and Ti-46. A constant value of M-p across the triplet has been observed. Shell-model calculations performed within the fp shell fail to reproduce this unexpected trend, pointing towards the need of a wider valence space. This result is confirmed by the good agreement with experimental data achieved with an interaction which allows excitations from the underlying sd shell. A test of the linearity rule for all published data on complete T = 1 isospin triplets is presented. |
| Address |
[Boso, A.; Recchia, F.; Lenzi, S. M.; John, P. R.; Grassi, L.; Mengoni, D.] Univ Padua, Dipartimento Fis & Astron Galileo Galilei, I-35131 Padua, Italy, Email: michael.bentley@york.ac.uk |
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Thesis |
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| Publisher |
Elsevier |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0370-2693 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000488071200023 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4158 |
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| Author |
Biswas, S. et al; Perez-Vidal, R.M. |
| Title |
Prompt-delayed gamma-ray spectroscopy of neutron-rich In-119, In-121 isotopes |
Type |
Journal Article |
| Year |
2020 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
102 |
Issue |
1 |
Pages |
014326 - 10pp |
| Keywords |
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| Abstract |
Background: The Z = 50 shell closure, near N = 82, is unique in the sense that it is the only shell closure with the spin-orbit partner orbitals, pi g(9/2) and pi g(7/2), enclosing the magic gap. The interaction of the proton hole/particle in the above-mentioned orbitals with neutrons in the nu h(11)(/2) orbital is an important prerequisite to the understanding of the nuclear structure near N = 82 and the nu pi interaction. Purpose: To explore the structural similarity between the high-spin isomeric states in In (Z = 49), Sn (Z = 50), and Sb (Z = 51) isotopes from a microscopic point of view. In addition, to understand the role of a proton hole or particle in the spin-orbit partner orbitals, pi g(9/2) and pi g(7/2), respectively, with neutron holes in the nu h(11)(/2) orbital on these aforementioned isomers. Methods: The fusion and transfer induced fission reaction Be-9(U-238, f) with 6.2 MeV/u beam energy, using a unique setup consisting of AGATA, VAMOS ++, and EXOGAM detectors, was used to populate through the fission process and study the neutron-rich In-119,In-121 isotopes. This setup enabled the prompt-delayed gamma-ray spectroscopy of isotopes in the time range of 100 ns-200 μs. Results: In the odd-A In-119,In-121 isotopes, indications of a short half-life 19/2(-) isomeric state, in addition to the previously known 25/2(+) isomeric state, were observed from the present data. Further, new prompt transitions above the 25/2(+) isomer in In-121 were identified along with reevaluation of its half-life. Conclusions: The experimental data were compared with the theoretical results obtained in the framework of large-scale shell-model calculations in a restricted model space. The <pi g(9/2)nu h(11/2); I vertical bar H vertical bar pi g(9/2) nu h(11/2);I > two-body matrix elements of residual interaction were modified to explain the excitation energies and the B(E2) transition probabilities in the neutron-rich In isotopes. The (i) decreasing trend of E(29/2(+))-E(25/2(+)) in odd-In (with dominant configuration pi g(9/)(2)(-1) nu h(11/2)(-2) and maximum aligned spin of 29/2+) and (ii) increasing trend of E(27/2(+)) – E(23/2(+)) in odd-Sb (with dominant configuration pi g(7/)(2)(+1) nu h(11/2)(-2) and maximum aligned spin of 27/2(+)) with increasing neutron number could be understood as a consequence of hole-hole and particle-hole interactions, respectively. |
| Address |
[Biswas, S.; Lemasson, A.; Rejmund, M.; Navin, A.; Kim, Y. H.; Michelagnoli, C.; Clement, E.; de France, G.; Fremont, G.; Goupil, J.; Jacquot, B.; Li, H. J.; Menager, L.; Morel, V; Ropert, J.] GANIL, CEA, DRF, CNRS,IN2P3, Bd Henri Becquerel,BP 55027, F-14076 Caen 05, France, Email: lemasson@ganil.fr |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000556554700003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4489 |
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| Author |
Siciliano, M. et al; Gadea, A.; Perez-Vidal, R.M. |
| Title |
Lifetime measurements in the even-even Cd102-108 isotopes |
Type |
Journal Article |
| Year |
2021 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
104 |
Issue |
3 |
Pages |
034320 - 16pp |
| Keywords |
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| Abstract |
Background: The heaviest T-z = 0 doubly-magic nucleus, Sn-100, and the neighboring nuclei offer unique opportunities to investigate the properties of nuclear interaction. For instance, the structure of light-Sn nuclei has been shown to be affected by the delicate balance between nuclear-interaction components, such as pairing and quadrupole correlations. From Cd to Te, many common features and phenomena have been observed experimentally along the isotopic chains, leading to theoretical studies devoted to a more general and comprehensive study of the region. In this context, having only two proton holes in the Z = 50 shell, the Cd isotopes are expected to present properties similar to those found in the Sn isotopic chain. Purpose: The aim of this work was to measure lifetimes of excited states in neutron-deficient nuclei in the vicinity of Sn-100. Methods: The neutron-deficient nuclei in the N approximate to Z approximate to 50 region were populated using a multinucleon transfer reaction with a Cd-106 beam and a Mo-92 target. The beamlike products were identified by the VAMOS++ spectrometer, while the gamma rays were detected using the AGATA array. Lifetimes of excited states were determined using the recoil distance Doppler-shift method, employing the Cologne differential plunger. Results: Lifetimes of low-lying states were measured in the even-mass Cd-102-(108) isotopes. In particular, multiple states with excitation energy up to MeV, belonging to various bands, were populated in approximate to 3 Cd-106 via inelastic scattering. The transition strengths corresponding to the measured lifetimes were compared with those resulting from state-of-the-art beyond-mean-field calculations using the symmetry-conserving configuration-mixing approach. Conclusions: Despite the similarities in the electromagnetic properties of the low-lying states, there is a fundamental structural difference between the ground-state bands in the Z = 48 and Z = 50 isotopes. The comparison between experimental and theoretical results revealed a rotational character of the Cd nuclei, which have prolate-deformed ground states with beta(2) approximate to 0.2. At this deformation Z = 48 becomes a closed-shell configuration, which is favored with respect to the spherical one. |
| Address |
[Siciliano, M.] Univ Paris Saclay, Irfu CEA, Gif Sur Yvette, France |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9985 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000704568900001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4998 |
| Permanent link to this record |
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| Author |
Biswas, S. et al; Perez-Vidal, R.M.; Domingo-Pardo, C. |
| Title |
Effects of one valence proton on seniority and angular momentum of neutrons in neutron-rich(51)( 122-)(131)Sb isotopes |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
99 |
Issue |
6 |
Pages |
064302 - 21pp |
| Keywords |
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| Abstract |
Background: Levels fulfilling the seniority scheme and relevant isomers are commonly observed features in semimagic nuclei; for example, in Sn isotopes (Z = 50). Seniority isomers in Sn, with dominantly pure neutron configurations, directly probe the underlying neutron-neutron (vv) interaction. Furthermore, an addition of a valence proton particle or hole, through neutron-proton (v pi) interaction, affects the neutron seniority as well as the angular momentum. Purpose: Benchmark the reproducibility of the experimental observables, like the excitation energies (E-x) and the reduced electric-quadrupole transition probabilities [B(E2)], with the results obtained from shell-model interactions for neutron-rich Sn and Sb isotopes with N < 82. Study the sensitivity of the aforementioned experimental observables to the model interaction components. Furthermore, explore from a microscopic point of view the structural similarity between the isomers in Sn and Sb, and thus the importance of the valence proton. Methods: The neutron-rich Sb122-131 isotopes were produced as fission fragments in the reaction Be-9(U-238, f) with 6.2 MeV/u beam energy. A unique setup, consisting of AGATA, VAMOS++, and EXOGAM detectors, was used which enabled the prompt-delayed gamma-ray spectroscopy of fission fragments in the time range of 100 ns to 200 μs. Results: New isomers and prompt and delayed transitions were established in the even-A Sb122-131 isotopes. In the odd-A Sb122-131 isotopes, new prompt and delayed gamma-ray transitions were identified, in addition to the confirmation of the previously known isomers. The half-lives of the isomeric states and the B(E2) transition probabilities of the observed transitions depopulating these isomers were extracted. Conclusions: The experimental data was compared with the theoretical results obtained in the framework of large-scale shell-model (LSSM) calculations in a restricted model space. Modifications of several components of the shell-model interaction were introduced to obtain a consistent agreement with the excitation energies and the B(E2) transition probabilities in neutron-rich Sn and Sb isotopes. The isomeric configurations in Sn and Sb were found to be relatively pure. Furthermore, the calculations revealed that the presence of a single valence proton, mainly in the g(7/2) orbital in Sb isotopes, leads to significant mixing (due to the v pi interaction) of (i) the neutron seniorities (upsilon(v)) and (ii) the neutron angular momentum (I-v). The above features have a weak impact on the excitation energies, but have an important impact on the B(E2) transition probabilities. In addition, a constancy of the relative excitation energies irrespective of neutron seniority and neutron number in Sn and Sb was observed. |
| Address |
[Biswas, S.; Lemasson, A.; Rejmund, M.; Navin, A.; Kim, Y. H.; Michelagnoli, C.; Clement, E.; de France, G.; Fremont, G.; Goupil, J.; Jacquot, B.; Li, H. J.; Menager, A.; More, V; Ropert, J.; Lefevre, A.; Saillant, F.] CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France, Email: biswas@ganil.fr; |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9985 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000470856500002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4051 |
| Permanent link to this record |
