Speaker
Michael Seidlitz
(Institut für Kernphysik, Universität zu Köln)
Description
For the $^{28,29,30}$Na isotopes a gradual transition from the usual filling of the neutron levels into the region with low lying 2p-2h cross shell configurations, the so-called island of inversion, is described by theory [1,2]. Detailed theoretical predictions for the transition strength are awaiting experimental verification in all three Na nuclei. Collective properties of excited states of $^{29,30}$Na were subject of a recent Coulomb excitation experiment at REX-ISOLDE employing radioactive $^{29,30}$Na beams with a final energy of 2.85 MeV/u. De-excitation $\gamma$-rays were detected by the MINIBALL $\gamma$-spectrometer in coincidence with scattered particles in a CD-shaped segmented Si-detector. The recently determined $B(E2)$ value [3] for the $5/2^+$ level in $^{29}$Na at 72 keV could be confirmed. A preliminary $B(E2)\!\!\!\uparrow = 350(65)$ $e^2$fm$^4$ value for the $2^+ \rightarrow 3^+$ transition in $^{30}$Na is of similar strength like the $0^+ \rightarrow 2^+$ transition strength in the neighboring $^{32}$Mg. The new data show clearly an increase in collectivity for the neutron rich Na case, indicating a deformed intruder dominated ground state configuration.\\
[1] T. Otsuka \emph{et al.}, Phys. Rev. Lett. {\bf 87}, 082502 (2001)\\
[2] Y. Utsuno \emph{et al.}, Phys. Rev. C {\bf 70}, 044307 (2004)\\
[3] A.M. Hurst \emph{et al.}, Phys. Lett. B {\bf 674}, 168-171 (2009)\\
Primary author
Michael Seidlitz
(Institut für Kernphysik, Universität zu Köln)
Co-authors
A. Blazhev
(Institut für Kernphysik, Universität zu Köln, Germany)
B. Bastin
(IKS, Katholieke Universiteit Leuven, Belgium)
B. Bruyneel
(Institut für Kernphysik, Universität zu Köln, Germany)
B. Siebeck
(Institut für Kernphysik, Universität zu Köln, Germany)
D. DiJulio
(Lund University, Sweden)
D. Voulot
(ISOLDE, CERN, Switzerland)
F. Wenander
(ISOLDE, CERN, Switzerland)
J. Cederkäll
(Lund University, Sweden)
J. Diriken
(IKS, Katholieke Universiteit Leuven, Belgium)
J. Taprogge
(Institut für Kernphysik, Universität zu Köln, Germany)
J. Van de Walle
(ISOLDE, CERN, Switzerland)
K. Wimmer
(Technische Universität München, Germany)
K. Wrzosek
(University of Warsaw, Poland)
L. Gaffney
(University of Liverpool, United Kingdom)
M. Huyse
(IKS, Katholieke Universiteit Leuven, Belgium)
M. Scheck
(University of Liverpool, United Kingdom)
N. Bree
(IKS, Katholieke Universiteit Leuven, Belgium)
N. Kesteloot
(IKS, Katholieke Universiteit Leuven, Belgium)
N. Warr
(Institut für Kernphysik, Universität zu Köln, Germany)
P. Butler
(University of Liverpool, United Kingdom)
P. Delahaye
(ISOLDE, CERN, Switzerland)
P. Reiter
(Institut für Kernphysik, Universität zu Köln, Germany)
P. Van Duppen
(IKS, Katholieke Universiteit Leuven, Belgium)
P.J. Woods
(University of Edinburgh, United Kingdom)
R. Gernhäuser
(Technische Universität München, Germany)
R. Krücken
(Technische Universität München, Germany)
R. Lutter
(Technische Universität München, Germany)
T. Davinson
(University of Edinburgh, United Kingdom)
T. Kröll
(IKP, Technical University Darmstadt, Germany)
