1. High-spin structures in the 139Pr nucleus.
- Author
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Yeoh, E. Y., Zhu, S. J., Wang, J. G., Xiao, Z. G., Zhang, M., Yan, W. H., Wang, R. S., Xu, Q., Wu, X. G., He, C. Y., Li, G. S., Zheng, Y., Li, C. B., Cao, X. P., Hu, S. P., Yao, S. H., and Yu, B. B.
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NUCLEAR spin , *NUCLEAR structure , *PRASEODYMIUM isotopes , *NEUTRONS , *NUCLEAR reactions , *NUCLEAR physics - Abstract
Background: 139Pr is located in a transitional region of neutron number close to the N = 82 shell. The study of its high-spin states and collective bands is important for systematically understanding the nuclear structural characteristics in this region. Purpose: To investigate the high-spin levels and to search for oblate bands in 139Pr. Methods: The high-spin states of 139Pr have been studied via the reaction 124Sn(19F,4n) at a beam energy of 80 MeV. The experiment was carried out at the HI-13 Tandem Accelerator at the China Institute of Atomic Energy (CIAE). The data analysis was done by using the &ggr;-&ggr; coincidence method. Results: The level scheme of 139Pr has been expanded with spin up to 45/2ħ. A total of 39 new levels and 45 new transitions are identified. Four collective band structures at high-spin states have been newly established. From systematic analysis, one of the bands is proposed as a double decoupled band; two bands are proposed as oblate bands with &ggr; ∼ -60° another band is suggested as an oblate-triaxial band with &ggr; ∼ --90&dgr;. The other characteristics for these bands are discussed. Conclusions: A new level scheme in 139Pr has been established and the collective bands at high spin have been identified. The result shows that the strong oblate shape-driving effect is caused by neutrons at the high-spin states in 139Pr. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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