Abstract
Background: Pr is located in a transitional region of neutron number close to the 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 Pr.
Methods: The high-spin states of Pr have been studied via the reaction Sn(F,4) 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 - coincidence method.
Results: The level scheme of Pr has been expanded with spin up to 45/2. 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 ; another band is suggested as an oblate-triaxial band with . The other characteristics for these bands are discussed.
Conclusions: A new level scheme in Pr 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 Pr.
- Received 13 May 2012
DOI:https://doi.org/10.1103/PhysRevC.85.064322
©2012 American Physical Society