Evolving collectivity at high spins in /sup 157/Er, /sup 158/Er, and /sup 159/Er

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.33.1988· OSTI ID:5523073

Oshima, M; Johnson, N R; McGowan, F K; Baktash, C; Lee, I Y; Schutz, Y; Ribas, R V; Wells, J C

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), Journal Name: Phys. Rev. C; (United States) Vol. 33:6; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
COMPOUND-NUCLEUS REACTIONS
DATA
DISTRIBUTION
DOPPLER EFFECT
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY RANGE
ERBIUM 157
ERBIUM 158
ERBIUM 159
ERBIUM ISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FERMIONS
GAMMA RADIATION
HADRONS
HEAVY ION REACTIONS
HIGH SPIN STATES
HOURS LIVING RADIOISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
LIFETIME
MATRIX ELEMENTS
MEV RANGE
MEV RANGE 100-1000
NEUTRONS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUMERICAL DATA
RADIATIONS
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
RECOILS
SPECTRAL SHIFT
SULFUR 34 REACTIONS
TARGETS
TELLURIUM 128 TARGET
YRAST STATES