Loss of collectivity in the transitional {sup 156}Er nucleus at high spin

Journal Article · Wed Apr 15 00:00:00 EDT 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.79.044324· OSTI ID:21289871

Paul, E S; Rigby, S V; Choy, P T. W.; Evans, A O; Nolan, P J ^[1]; Riley, M A; Campbell, D B; Pipidis, A ^[2]; Simpson, J; Appelbe, D E; Joss, D T ^[3]; Clark, R M; Cromaz, M; Fallon, P; Goergen, A; Lee, I Y; Macchiavelli, A O; Ward, D ^[4]; Ragnarsson, I ^[5]

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1. Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom)
2. Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States)
3. STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom)
4. Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
5. Division of Mathematical Physics, LTH, Lund University, Post Office Box 118, S-22100 Lund (Sweden)

The {sup 114}Cd({sup 48}Ca,6n{gamma}) reaction at 215 MeV has been investigated using the Gammasphere spectrometer to study the high-spin structure of the nucleus {sub 68}{sup 156}Er{sub 88}. Many new transitions have been established along with definitive spin-parity level assignments from a high-fold angular-distribution analysis. In addition, absolute B(M1) and B(E1) strengths have been inferred from measured {gamma}-ray branching ratios. Strong B(E1) strength (10{sup -3} W.u.) is discussed in terms of possible octupole collectivity at low spin. At high spin, this nucleus undergoes a Coriolis-induced shape transition from a prolate state of collective rotation to a noncollective, triaxial-oblate configuration. The yrast positive-parity structure ultimately terminates in an energetically favored oblate state at I{sup {pi}}=42{sup +}. Several weak high-energy {gamma}-ray transitions have been discovered that feed this favored state. State-of-the-art cranked Nilsson-Strutinsky calculations are used to interpret the high-spin behavior of {sup 156}Er and comparisons are made with other N=88 isotones.

• OSTI ID: 21289871
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 79, Issue 4; Other Information: DOI: 10.1103/PhysRevC.79.044324; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALLOCATIONS
ANGULAR DISTRIBUTION
ASTATINE 215
BRANCHING RATIO
CADMIUM 114
CALCIUM 48
COMPARATIVE EVALUATIONS
E1-TRANSITIONS
ERBIUM 156
GAMMA DECAY
GAMMA RADIATION
ISOTONIC NUCLEI
LOSSES
M1-TRANSITIONS
MEV RANGE 100-1000
NUCLEAR REACTIONS
OCTUPOLES
SPECTROMETERS
SPIN
YRAST STATES