Structure of the N=50 As, Ge, Ga nuclei

WOS: 000310091000001
The level structures of the N = 50 As-83, Ge-82, and Ga-81 isotones have been investigated by means of multi-nucleon transfer reactions. A first experiment was performed with the CLARA PRISMA setup to identify these nuclei. A second experiment was carried out with the GASP array in order to deduce the gamma-ray coincidence information. The results obtained on the high-spin states of such nuclei are used to test the stability of the N = 50 shell closure in the region of Ni-78 (Z = 28). The comparison of the experimental level schemes with the shell-model calculations yields an N = 50 energy gap value of 4.7(3) MeV at Z = 28. This value, in a good agreement with the prediction of the finite-range liquid-drop model as well as with the recent large-scale shell model calculations, does not support a weakening of the N = 50 shell gap down to Z = 28. (c) 2012 Elsevier B.V. All rights reserved.
NSF [PHY0244389, PHY0555396]; European Commission within the Sixth Framework Programme through I3-EURONS [RII3-CT-2004-506065]; DGF (Germany) [DE 1516/-1]; Science and Technology Facilities Council [ST/G000689/1 NuSTAR, ST/F004052/1, ST/G000689/1, ST/J000108/1]
We thank O. Sorlin for the useful discussions and the accelerator crews of LNL for the excellent support. A.F.L. acknowledges partial support of this work from NSF grants PHY0244389 and PHY0555396. This work has been partially supported by the European Commission within the Sixth Framework Programme through I3-EURONS (contract No. RII3-CT-2004-506065) and the DGF (Germany under contract No. DE 1516/-1).