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Author AGATA Collaboration (Louchart, C. et al); Gadea, A.; Huyuk, T.
Title Collective nature of low-lying excitations in 70,72,74Zn from lifetime measurements using the AGATA spectrometer demonstrator Type Journal Article
Year 2013 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 87 Issue 5 Pages 054302 - 10pp
Keywords
Abstract Background: Neutron-rich nuclei with protons in the fp shell show an onset of collectivity around N=40. Spectroscopic information is required to understand the underlying mechanism and to determine the relevant terms of the nucleon-nucleon interaction that are responsible for the evolution of the shell structure in this mass region. Methods: We report on the lifetime measurement of the first 2+ and 4+ states in 70,72,74Zn and the first 6+ state in 72Zn using the recoil distance Doppler shift method. The experiment was carried out at the INFN Laboratory of Legnaro with the AGATA demonstrator, first phase of the Advanced Gamma Tracking Array of highly segmented, high-purity germanium detectors coupled to the PRISMA magnetic spectrometer. The excited states of the nuclei of interest were populated in the deep inelastic scattering of a 76Ge beam impinging on a 238U target. Results: The maximum of collectivity along the chain of Zn isotopes is observed for 72Zn at N=42. An unexpectedly long lifetime of 20−5.2+1.8 ps was measured for the 4+ state in 74Zn. Conclusions: Our results lead to small values of the B(E2;41+→21+)/B(E2;21+→01+) ratio for 72,74Zn, suggesting a significant noncollective contribution to these excitations. These experimental results are not reproduced by state-of-the-art microscopic models and call for lifetime measurements beyond the first 2+ state in heavy zinc and nickel isotopes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
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Area Expedition Conference
Notes (up) Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1638
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Author Caballero, L.; Rubio, B.; Kleinheinz, P.; Yates, S.W.; Algora, A.; Dewald, A.; Fitzler, A.; Gadea, A.; Jolie, J.; Julin, R.; Linnemann, A.; Lunardi, S.; Menegazzo, R.; Moller, O.; Nacher, E.; Piiparinen, M.; Blomqvist, J.
Title Two-phonon octupole excitation in Gd-146 Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 81 Issue 3 Pages 031301 - 4pp
Keywords
Abstract Based on experimental evidence from the Sm-144(alpha,2n) reaction, the 3484.7- keV 6(+) state in Gd-146 is identified as the highest-spin member of the 3(-) circle times 3(-) two-phonon octupole quartet. A previously unknown gamma line of 1905.8 keV and E3 character feeding the 3(-) octupole state has been observed. These results represent the first observation of a 6(+) -> 3(-) -> 0(+) cascade of two E3 transitions in an even-even nucleus and provide strong support for the interpretation of the 6(+) state as a two-phonon octupole excitation.
Address [Caballero, L.; Rubio, B.; Algora, A.; Gadea, A.; Nacher, E.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: Berta.Rubio@ific.uv.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes (up) ISI:000276769400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 468
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Author Soderstrom, P.A. et al; Algora, A.; Gadea, A.
Title Spectroscopy of neutron-rich Dy-168,Dy-170: Yrast band evolution close to the NpNn valence maximum Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 81 Issue 3 Pages 034310 - 5pp
Keywords
Abstract The yrast sequence of the neutron-rich dysprosium isotope Dy-168 has been studied using multinucleon transfer reactions following collisions between a 460-MeV Se-82 beam and an Er-170 target. The reaction products were identified using the PRISMA magnetic spectrometer and the gamma rays detected using the CLARA HPGe-detector array. The 2(+) and 4(+) members of the previously measured ground-state rotational band of Dy-168 have been confirmed and the yrast band extended up to 10(+). A tentative candidate for the 4(+) -> 2(+) transition in Dy-170 was also identified. The data on these nuclei and on the lighter even-even dysprosium isotopes are interpreted in terms of total Routhian surface calculations and the evolution of collectivity in the vicinity of the proton-neutron valence product maximum is discussed.
Address [Soderstrom, P. -A.; Nyberg, J.] Uppsala Univ, Dept Phys & Astron, SE-75121 Uppsala, Sweden
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes (up) ISI:000276769400026 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 469
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Author Ljungvall, J. et al; Gadea, A.
Title Onset of collectivity in neutron-rich Fe isotopes: Toward a new island of inversion? Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 81 Issue 6 Pages 061301 - 4pp
Keywords
Abstract The lifetimes of the first excited 2(+) states in Fe-62 and Fe-64 have been measured for the first time using the recoil-distance Doppler shift method after multinucleon transfer reactions in inverse kinematics. A sudden increase of collectivity from Fe-62 to Fe-64 is observed. The experimental results are compared with new large-scale shell-model calculations and Hartree-Fock-Bogolyubov-based configuration-mixing calculations using the Gogny D1S interaction. The results give a deeper understanding of the mechanism leading to an onset of collectivity near Ni-68, which is compared with the situation in the so-called island of inversion around Mg-32.
Address [Ljungvall, J.; Goergen, A.; Obertelli, A.; Korten, W.] CEA Saclay, IRFU, Serv Phys Nucl, F-91191 Gif Sur Yvette, France
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes (up) ISI:000278768900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 424
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Author Mengoni, D. et al; Gadea, A.; Algora, A.; Rubio, B.
Title Lifetime measurements of excited states in neutron-rich Ar-44,Ar-46 populated via a multinucleon transfer reaction Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 82 Issue 2 Pages 024308 - 7pp
Keywords
Abstract Lifetimes of low-lying excited states of the neutron-rich Ar-44,Ar-46 nuclei, populated via multinucleon transfer reactions, are measured by means of the differential recoil distance Doppler shift method. The extracted electromagnetic transition probabilities are compared with previous intermediate-energy Coulomb-excitation measurements and with large-scale shell-model calculations. The increase in the deduced B( E2; 2(+) -> 0(+)) transition probability from Ar-44 to the closed-shell nucleus Ar-46 contradicts the earlier results of Coulomb-excitation experiments. Shell-model calculations using different effective interactions agree with the new measured values.
Address [Mengoni, D.; Angus, L. J.; Orlandi, R.; Smith, J. F.; Wady, P. T.] Univ W Scotland, Sch Engn, Paisley PA1 2BE, Renfrew, Scotland, Email: mengoni@pd.infn.it
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes (up) ISI:000280759100002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 394
Permanent link to this record