Bochum 1998 – wissenschaftliches Programm
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HK: Hadronen und Kerne
HK 50: Spectroscopy: 130 ≤ A ≤ 180
HK 50.4: Gruppenbericht
Mittwoch, 18. März 1998, 15:00–15:30, D
Search for the Decay-out of the Yrast Superdeformed Band in 144Gd — •R.M. Lieder1, S. Lunardi2, D. Bazzacco2, G. Falconi2, R. Menegazzo2, P. Pavan2, C.M. Petrache2, C. Rossi-Alvarez2, C.A. Ur2, R. Venturelli2, M. DePoli3, A. Gadea3, G. de Angelis3, D.R. Napoli3, Z. Podolyak3, W. Gast1, A. Georgiev1, H.M. Jäger1, H.J. Jensen1, T. Rzaca-Urban4, W. Urban4, Z. Pytel4, M. Augsburg4, K. Starosta4, C.A. Kalfas5, C.T. Papadopoulos6, and R. Vlastou6 — 1Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich — 2INFN, Sezione di Padova, I-35131 Padova — 3INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro — 4Institute of Experimental Physics, University of Warsaw, PL-00-681 Warsaw — 5Institute of Nuclear Physics, NCRS Demokritos, GR-15310 Athens — 6National Technical University of Athens, GR-5773 Athens
In order to identify discrete transitions linking the yrast superdeformed (SD) band of 144Gd to the normal-deformed (ND) states an experiment has been carried out with the γ-detector array EUROBALL III at the XTU tandem accelerator of the Laboratori Nazionali di Legnaro, Italy. The final nucleus was produced with the 100Mo(48Ti,4n) reaction at 215 MeV. Information about the deexcitation of SD bands exists only for a few cases, because the intensities of the already weak SD bands fragment into so many branches that an identification of the discrete linking transitions is experimentally very difficult. This knowledge is required, however, to determine the excitation energies, spins and parities of SD bands. In the mass A=150 region a candidate for a single-step linking transition has been found only for 143Eu [1], which has an energy of 3361 keV. The nucleus 144Gd seems to be a good case to search for discrete linking transitions because the decay-out of the yrast SD band takes place below the backbending, caused by the alignment of two N=6 protons, where no high-N intruder orbitals are occupied any longer. Accordingly, the deformation is expected to be smaller than for the upper part of this SD band and a larger mixing with ND states may be expected. In the EUROBALL III experiment about 3 · 109 events with an average γ-ray multiplicity of four have been collected. The analysis is in progress and the linking transition of 3361 keV in 143Eu, which is produced as byproduct, has been confirmed. (Supported by the EU, Volkswagen Foundation and KBN).
[1] A. Ataç et al., Z. Phys. A355, 343 (1996)