As part of a research program to study the transitional region of N=88
isotones, ¹⁵²Tb was produced by the reaction ¹⁵¹Eu(α,3n)¹⁵²Tb in the 88" cyclotron
located at LBNL. Gamma-ray spectroscopy of the radiation emitted from excited
¹⁵²Gd following the β⁺ decay of ¹⁵²Tb has been performed using an array of 20
germanium detectors. The large Q-value (3990 keV) of the ¹⁵²Tb 2⁻ decay allows for
the population of many levels; study of coincidence and single events resulted in the
establishment of 54 new levels and 266 new transitions. Angular correlation of the
coincidences has determined spin and parity of many levels with several seen as key to
the band structure, including two new 0⁺ levels. One new rotational band including
the new 1475.2 keV 0⁺ level and the 1771.7 keV 2⁺ level is proposed. The overall
band structure compared to collective excitation models demonstrates the position of
¹⁵²Gd in the transition from a spherical to deformed shape, also seen in other N=88
isotones. Monopole transition strength among bands indicates the possibility of
mixing of both shapes among the excited states. The remarkable similarity of the band
structure among these isotones is discussed. / Graduation date: 2005
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28956 |
| Date | 20 September 2004 |
| Creators | Stapels, Christopher John |
| Contributors | Krane, Kenneth Saul |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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