Non-yrast states of Ce-132 populated in beta-decay

Non-yrast low spin states of the nucleus Ce-132 were studied by means of ga mma-spectroscopy following the beta-decay of the ground and medium spin iso meric states of Pr-132. The activity was produced with the reaction Sn-117( F-19, 4n) Pr-132 at the Cologne FN TANDEM accelerator. The gamma gamma coin cidences and singles spectra were measured with the OSIRIS cube spectromete r. The beta-decay of Pr-132 populates states with spins up to 6 (H) over ba r and excitation energies up to 4.4 MeV in Ce-132. Besides ground and quasi -gamma bands, an excited band based on the 0(2)(+) state and many other low -lying states were observed. The gamma gamma angular correlations were anal yzed to assign spins and parities to the excited states, and to determine t he multipolarities of the gamma-transitions, We found dominant E2 transitio ns in the quasi-gamma band and from the quasi-gamma band to the ground band . The experimental data are compared with calculations using the Interactin g Boson Model (IBM). Good agreement is reached in the vicinity of the O(6) limit. O 1998 Elsevier Science B.V.