2018 Impact factor 2.481
Hadrons and Nuclei
Eur. Phys. J. A 3, 25-48

Nuclear levels in 228Th populated in the decay of 228Pa (II)

T. Weber1 - J. de Boer2 - K. Freitag1 - J. Gröger1 - C. Günther1 - P. Herzog1 - V.G. Soloviev3 - A.V. Sushkov3 - N.Yu. Shirikova3

1 Institut für Strahlen- und Kernphysik, Universität Bonn, Nussallee 14-16, D-53115 Bonn, Germany
2 Sektion Physik, Universität München, Am Coulombwall 1, D-85748 Garching, Germany
3 Bogolubov Laboratory of Theoretical Physics, Joint Institute of Nuclear Research, 141980 Dubna, Russia

Received: 30 March 1998 Communicated by D. Schwalm

Abstract
The electron-capture decay of 228Pa to levels in 228Th was studied using mass-separated sources and a $\gamma$-ray detection system consisting of five Compton-suppressed Ge detectors. A total of 87 levels were observed up to an excitation energy of 2 MeV which are connected by approximately 500 $\gamma$-ray transitions. The complete octupole quadruplet, three excited $K^{\pi}=0^{+}$ bands and two $K^{\pi}=2^{+}$ bands were identified below 1.4 MeV. The observed level structure is compared to calculations within the quasiparticle-phonon nuclear model. The surprisingly good agreement indicates that 228Th has less transitional character than hitherto assumed.

PACS
23.20.-g Electromagnetic transitions - 21.60.Jz Hartree-Fock and random-physe approximations - 27.90.+b $220 \le A$


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