Evolving collectivity at high spins in /sup 157/Er, /sup 158/Er, and /sup 159/Er
Lifetimes of high-spin states in /sup 157,158,159/Er have been measured following the reaction /sup 128/Te(/sup 34/S,xn) induced by 155-MeV /sup 34/S ions. A Doppler-shift recoil-distance device was used and ..gamma..-..gamma.. coincidences were recorded between five germanium detectors at 90/sup 0/ to the beam direction and a Compton-suppressed Ge detector at 0/sup 0/ to record the shifted and unshifted ..gamma..-ray peaks. The results for the ground band of /sup 158/Er clearly show increasing collectivity with spin, an effect probably arising from centrifugal stretching for this N = 90 nucleus. In the s band, formed by the alignment of a pair of i/sub 13/2/ neutrons, there is a significant reduction in the collectivity, which appears to have a rotational-frequency dependence similar to that found earlier for /sup 160/Yb and interpreted as possibly arising from movement toward triaxiality in the nuclear shape. Four states each in the yrast bands of /sup 157/Er and /sup 159/Er were also measured, and here, too, a similar reduction of collectivity at higher rotational frequencies is observed.
- Research Organization:
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5523073
- Journal Information:
- Phys. Rev. C; (United States), Vol. 33:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ERBIUM 157
HIGH SPIN STATES
ERBIUM 158
ERBIUM 159
SULFUR 34 REACTIONS
COMPOUND-NUCLEUS REACTIONS
TELLURIUM 128 TARGET
ANGULAR DISTRIBUTION
COINCIDENCE SPECTROMETRY
DOPPLER EFFECT
EXPERIMENTAL DATA
GAMMA RADIATION
LIFETIME
MATRIX ELEMENTS
MEV RANGE 100-1000
NEUTRONS
RECOILS
SPECTRAL SHIFT
YRAST STATES
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CHARGED-PARTICLE REACTIONS
DATA
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY RANGE
ERBIUM ISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
HADRONS
HEAVY ION REACTIONS
HOURS LIVING RADIOISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
MEV RANGE
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUMERICAL DATA
RADIATIONS
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
TARGETS
651823* - Nuclear Properties & Reactions
A=150-189
Experimental- Energy Levels & Transitions- (-1987)
651725 - Nuclear Properties & Reactions
A=90-149
Experimental- Nuclear Reactions & Scattering- (-1987)