Speaker
Dr
Christophe Olivier Sotty
("Horia Hulubei" National Institute for Physics and Nuclear Engineering, 077125 Bucharest-Magurele, Romania)
Description
Exhibiting one of the most sudden onset of deformation, the neutron-rich A=100 mass region has recently attracted a vast interest from the nuclear structure community.
The influence of the neutron contribution to the deformation has been already well investigated in the Sr and Zr isotopes; however, a better understanding of the role played by the proton orbitals was needed to draw a complete picture of the mechanisms involved in the sudden onset of deformation.
A smooth development of collectivity has been recently observed in $^{96}$Kr via mass measurements and Coulomb excitation. The Rb isotopes exhibit a step increase of the quadrupole moment at N=60, indicating deep structural changes by just adding one proton compared to the Kr case.
In the present study, excited states of neutron-rich $^{97,99}$Rb were populated for the first time via Coulomb excitation using the REX-ISOLDE facility and the MINIBALL spectrometer. Complementary to the previous magnetic moment measurement, comparisons of the results with particle-rotor model calculations allowed for unambiguous assignment of the $\pi g_{9/2}[431]3/2^{+}$ Nilsson-model orbital as the configuration of the ground state of $^{97}$Rb on top of which the rotational band is built. The degree of deformation in the band is essentially similar to what has been observed well inside the deformation region around A$\sim$100, such as in the Sr and Zr cases.
Moreover, this study highlights the potential of the Coulomb excitation technique to obtain further spectroscopy information far from stability.
Revealing a similar structure, the $^{99}$Rb case constituted a challenge, pushing the limits of studying very short lived post-accelerated radioactive beams.
Authors
Prof.
Andrew Stuchbery
(Department of Nuclear Physics, Australian National University, Canberra, Australia)
Dr
Christophe Olivier Sotty
("Horia Hulubei" National Institute for Physics and Nuclear Engineering, 077125 Bucharest-Magurele, Romania)
Prof.
Dimiter Balabanski
(ELI-NP, IFIN-HH, 30 Reactorului Str., 077125 Bucharest - M\u{a}gurele, RomaniaELI-NP, IFIN-HH, 30 Reactorului Str., 077125 Bucharest - Magurele, Romania)
Georgi Georgiev
(CSNSM Centre de Spectrometrie Nucle aire et de Spectrometrie de)
Dr
Magdalena Zielinska
(RFU/SPhN, CEA Saclay, F-91191, Gif-sur-Yvette, France)
Co-authors
Andrey Atanasov Blazhev
(Institut fur Kernphysik - Universitaet zu Koeln)
Burkhard Siebeck
(Universitaet zu Koeln (DE))
Filip Kondev
(Argonne National Laboratory)
Fredrik John Carl Wenander
(CERN)
Gary Simpson
(LPSC)
Hans Toshihide Tornqvist
(Chalmers University of Technology (SE))
Hilde De Witte
(KU Leuven (BE))
Jan Diriken
(Katholieke Universiteit Leuven)
Janne Pakarinen
(University of Jyvaskyla (FI))
Dr
Jean-Michel Daugas
(CEA, DAM, DIF, F-91297 Arpajon cedex, France)
Joonas Konki
(U)
Dr
K. Geibel
(IKP, University of Cologne, D-50937 Cologne, Germany)
Dr
Katarzyna Hadynska-Klek
(Heavy Ion Laboratory, University of Warsaw, 02-093 Warsaw, Poland)
Liam Gaffney
(KU Leuven (BE))
Marcus Scheck
(IKP TU Darmstadt)
Michael Seidlitz
(Universitaet zu Koeln (DE))
Nick Bree
(Inst. voor Kern- en Stralingsfysica - Katholieke Universiteit Le)
Nigel Victor Warr
(Universitaet zu Koeln (DE))
Pawel Napiorkowski
(Institute of Experimental Physics)
Peter Reiter
(Universitaet zu Koeln (DE))
Pierre Morel
(Unknown)
Dr
Raphael Chevrier
(CEA, DAM, DIF, F-91297 Arpajon cedex, France)
Shinjinee Das Gupta
(Univ. di Camerino, Dipart. Fisica-Unknown-Unknown)
Thomas Davinson
(University of Edinburgh)
Thorsten Kroell
(Technische Universitaet Darmstadt (DE))
