Shape Transitional Nuclei: What can we learn from the Yrare States? or Hello the Double Vacuum; Goodbye {beta}-vibrations{exclamation_point}

Journal Article · Mon May 12 00:00:00 EDT 2008 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2939295· OSTI ID:21143346

Sharpey-Schafer, J F ^[1]; Mullins, S M; Bark, R A; Gueorguieva, E; Kau, J; Komati, F; Lawrie, J J; Murray, S H. T.; Ncapayi, N J ^[2]; Maine, P ^[1]; Minkova, A ^[3]; Vymers, P ^[1]

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1. University of Western Cape, Department of Physics, P/B X17, Bellville, ZA-7535 (South Africa)
2. iThemba Laboratory for Accelerator Based Sciences, PO Box 722, Somerset-West, ZA-7129 (South Africa)
3. Faculty of Physics, St. Kliment Ohridski University of Sofia, Sofia 1164 (Bulgaria)

The results of our measurements on the yrare states up to spin 20({Dirac_h}/2{pi}) in {sup 152,154,155}Gd, using ({alpha},xn) reactions and the AFRODITE {gamma}-ray spectrometer, are presented. We find that in {sup 155}Gd the decay scheme is divided into levels feeding the [505]11/2{sup -} band, that is extruded by the prolate deformation from the h{sub 11/2} orbital, and levels feeding the i{sub 13/2}[651]3/2{sup +} intruder orbital and the h{sub 9/2}[521]3/2{sup -} orbital. The decay scheme of {sup 154}Gd is very complex. We find no evidence for the existence of {beta}-vibrational levels below 1.5 MeV. We discover that the level scheme can be best understood as a set of collective states built on the ground state configuration |0{sub 1}{sup +}> plus a 'congruent' set of collective states based on the |0{sub 2}{sup +}> state at 681 keV. The data suggest that this second vacuum has reduced pairing. Our data do not support IBA and phonon interpretations of these transitional nuclei.

• OSTI ID: 21143346
• Journal Information: AIP Conference Proceedings, Vol. 1012, Issue 1; Conference: FINUSTAR: 2. conference on Frontiers In NUclear STructure, Astrophysics and Reactions, Crete (Greece), 10-14 Sep 2007; Other Information: DOI: 10.1063/1.2939295; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
GADOLINIUM 154
GADOLINIUM 155
GROUND STATES
KEV RANGE
MEV RANGE
NEUTRONS
NUCLEAR DECAY
NUCLEAR DEFORMATION
NUCLEAR STRUCTURE
PHONONS
SPIN
VIBRATIONAL STATES