Springer Online Journal Archives 1860-2000
Abstract TheK π=0− bands in even uranium nuclei were studied in the compound reactions231Pa(p, 2n)230U,230, 232Th(α,2n)232, 234U and236U(d, pn)236U. In-beamγ-rays were measured in coincidence with conversion-electrons, which were detected with an iron-free orange spectrometer. The negative-parity levels are observed up to intermediate spins (I〈13−). In addition, the 1− and 3− levels in230U were confirmed by a decay study with an isotope separated230Pa source. For the heavier isotopes (A≥232) the properties of theK π=0− bands (energies andγ-branchings) are consistent with a vibrational character of these bands. For230U theK π=0− band lies at rather low energy (E(1−)=367 keV), and the level spacings within this band are very similar to those of the isotones228Th and226Ra, which might indicate the onset of a stable octupole deformation.
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