Coulomb excitation of 29,30Na: Mapping the borders of the island of inversion

Phys. Rev. C

89
024309
(2014)
M. Seidlitz, P. Reiter, R. Altenkirch, B. Bastin, C. Bauer, A. Blazhev, N. Bree, B. Bruyneel, P. A. Butler, J. Cederkäll, T. Davinson, H. De Witte, D. D. DiJulio, J. Diriken, L. P. Gaffney, K. Geibel, G. Georgiev, R. Gernhäuser, M. Huyse, N. Kesteloot, T. Kröll, R. Krücken, R. Lutter, J. Pakarinen, F. Radeck, M. Scheck, D. Schneiders, B. Siebeck, C. Sotty, T. Steinbach, J. Taprogge, P. Van Duppen, J. Van de Walle, D. Voulot, N. Warr, F. Wenander, K. Wimmer, P. J. Woods, and K. Wrzosek-Lipska

Nuclear shell evolution in neutron-rich Na nuclei around 𝑁=20 was studied by determining reduced transition probabilities, i.e., 𝐵⁡(𝐸⁢2) and 𝐵⁡(𝑀⁢1) values, in order to map the border of the island of inversion. To this end Coulomb-excitation experiments, employing radioactive 29,30Na beams with a final beam energy of 2.85 Me⁢V/nucleon, were performed at REX-ISOLDE, CERN. De-excitation 𝛾 rays were detected by the MINIBALL 𝛾-ray spectrometer in coincidence with scattered particles in a segmented Si detector. Transition probabilities to excited states were deduced. The measured 𝐵⁡(𝐸⁢2) values agree well with shell-model predictions, supporting the idea that in the Na isotopic chain the ground-state wave function contains significant intruder admixture already at 𝑁=18, with 𝑁=19 having an almost pure two-particle–two-hole deformed ground-state configuration.

DOI
10.1103/PhysRevC.89.024309
Published on
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