Abstract
Nuclear levels in230Th have been investigated in theβ decay of230Pa, the230Th(d, pnγ) reaction and the232Th(p, t) reaction. TheK π=0 +1 , 2 +1 , and 2 +2 bands with band heads at 635, 781, and 1010 keV were observed up to the 8+, 9+, and 7+ levels, respectively. A second excited 0+ level was identified at 1297 keV which might be interpreted as the usualβ shape-oscillation. The branching ratios of theE2 transitions from the 0 +1 , 2 +1 , and 2 +2 bands are explained in the framework of the rotational model by taking into account the coupling of these bands with the ground-state band, and the coupling between the 0 +1 and 2 +1 band. A strong enhancement ofE2 transitions from the 2 +1 to the 0 +1 band reported earlier is not confirmed. For the octupole vibrations withK π=0−, 1−, and 2− theE1 branching ratios are analyzed in terms of the Coriolis coupling of these bands. An almost complete experimental set ofE1 transition moments from these negative-parity bands to the 0 +g , 0 +1 , and 2 +1 bands was obtained. It is suggested that octupole correlations might be important in explaining theseE1 moments.
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We appreciate the help of Mr. Assmus with the proton irradiations and the financial support of the Kernforschungszentrum Karlsruhe GmbH. This work was supported by the Deutsche Forschungsgemeinschaft (grants Bo 1109/1-1, Gr 894/2-1, Gu 179/3-1 and He 1316/2-3) and by the Volkswagen Stiftung.
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Ackermann, B., Baltzer, H., Freitag, K. et al. Experimental investigation of vibrational excitations in230Th. Z. Physik A - Hadrons and Nuclei 350, 13–28 (1994). https://doi.org/10.1007/BF01285047
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DOI: https://doi.org/10.1007/BF01285047