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Title page for ETD etd-12222007-132313


Type of Document Dissertation
Author Cluff, Warren Thomas
Author's Email Address cluff@nucmar.physics.fsu.edu
URN etd-12222007-132313
Title The High-Spin Structure of 134,135Ba and 120Te
Degree Doctor of Philosophy
Department Physics, Department of
Advisory Committee
Advisor Name Title
Mark A. Riley Committee Chair
Ingo Wiedenhoever Committee Member
Jorge Piekarewicz Committee Member
Pedro Schlottmann Committee Member
Sanford Safron Committee Member
Keywords
  • High-Spin
  • Structure
  • 134Ba
  • 135Ba
  • 120Te
Date of Defense 2007-12-12
Availability unrestricted
Abstract
High-spin states up to I~22, 37/2 and 24ћ have been studied in the 134,135Ba (Z=56) and 120Te (Z=52) nuclei respectively. The reaction used to populate 134Ba and 135Ba high-spin states was 124Sn(14C,4n and 3n) at a beam energy of 57 and 50 MeV respectively. High-spin states in 120Te were populated using the 110Pd(14C,4n) reaction at a beam energy of 64 MeV. Through these reactions and using the FSU gamma-ray detector array of Compton suppressed Ge detectors, significant extensions to the level schemes for each of these nuclei were made.

In 134Ba, a large number of states are observed for the first time beyond the 10+ isomer. The most prominent feature of the 134Ba level scheme is the newly discovered dipole (Δ I=1) band (group P). This structure is interpreted as oblate collective rotational in character with the configuration πg7/2 h11/2υh11/2-2. Comparisons with neighboring nuclei leading to this interpretation are discussed.

Previous to the present study only a handful of gamma-ray transitions had been assigned to 135Ba. In the present work a level scheme with over 25 new transitions and 24 new levels has been constructed for this nucleus. In the 135Ba level scheme the prominent feature is another dipole (ΔI=1) band (group F). This band is interpreted as the 3 quasiparticle configuration πh11/2g7/2υh11/2-1. Another interesting structure of this nucleus is the 21/2 level of group K which carries a substantial fraction (14%) of the decay intensity. This long lived level is interpreted as analogous to the 10+ isomeric state in 134Ba.

New structures in 120Te have been identified at high spin which indicate a transition to oblate non-collective structure. These observations are consistent with Cranked Nilsson Strutinsky calculations which predict specific favored configurations for high-spin states.

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