Gamma-ray spectroscopy of the doubly magic nucleus 56Ni.

Authors :: Johansson, E. K.
Rudolph, D.
Ekman, J.
Fahlander, C.
Andreoiu, C.
Bentley, M. A.
Carpenter, M. P.
Charity, R. J.
Clark, R. M.
Fallon, P.
Janssens, R. V. F.
Kondev, F. G.
Khoo, T. L.
Lauritsen, T.
Macchiavelli, A. O.
Reviol, W.
Sarantites, D. G.
Seweryniak, D.
Svensson, C. E.
Williams, S. J.
Source :: European Physical Journal A -- Hadrons & Nuclei; Feb2006, Vol. 27 Issue 2, p157-165, 9p, 1 Diagram, 3 Charts, 6 Graphs
Publication Year :: 2006
Abstract: The doubly magic N = Z nucleus <superscript>56</superscript>Ni has been investigated with two fusion-evaporation reactions; <superscript>40</superscript>Ca(<superscript>28</superscript>Si, 3α)<superscript>56</superscript>Ni at a beam energy of 122MeV and <superscript>28</superscript>Si(<superscript>32</superscript>S, 2p2n)<superscript>56</superscript>Ni at 130MeV. To detect γ-rays in coincidence with evaporated particles the Ge-detector array Gammasphere was used in conjunction with the charged-particle detector system, Microball and a 1π neutron detector array. Results include a significantly extended level scheme of <superscript>56</superscript>Ni, which is compared to large-scale shell model calculations in the fp shell. The experimental and theoretical results agree to a large extent, with one notable exception; the theoretical model fails to predict the proper sequence of the yrast and yrare 8<superscript>+</superscript> states. [ABSTRACT FROM AUTHOR]