0+ gs →2+ 1 Transition Strengths in 106 Sn and 108 Sn

Phys. Rev. Lett.

101
012502
(2008)
A. Ekstöm, J. Cederkäll, C. Fahlander, M. Hjorth-Jensen, F. Ames, P.A. Butler, T. Davinson, J. Eberth, F. Fincke, A. Görgen, M. Górska, D. Habs, A.M. Hurst, M. Huyse, O. Ivanov, J. Iwanicki, O. Kester, U. Köster, B.A. Marsh, J. Mierzejewski, P. Reiter, H. Scheit, D. Schwalm, S. Siem, G. Sletten, I. Stefanescu, G.M. Tveten, J. Van de Walle, P. Van Duppen, D. Voulot, N. Warr, D. Weißhaar, F. Wenander, M. Zielińska

The reduced transition probabilities, 𝐵⁡(𝐸⁢2;0+
gs →2+
1), have been measured in the radioactive isotopes  
108,106
 Sn 
  using subbarrier Coulomb excitation at the REX-ISOLDE facility at CERN. Deexcitation 𝛾 rays were detected by the highly segmented MINIBALL Ge-detector array. The results, 𝐵⁡(𝐸⁢2;0+
gs →2+
1) =0.222⁢(19)⁢𝑒2⁢𝑏2 for  
108
 Sn 
  and 𝐵⁡(𝐸⁢2;0+
gs →2+
1) =0.195⁢(39)⁢𝑒2⁢𝑏2 for  
106
 Sn 
  were determined relative to a stable  
58
 Ni 
  target. The resulting 𝐵⁡(𝐸⁢2) values are  ∼30% larger than shell-model predictions and deviate from the generalized seniority model. This experimental result may point towards a weakening of the 𝑁 =𝑍 =50 shell closure.

DOI
10.1103/PhysRevLett.101.012502
Published on
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