Quasiparticle alignment effects in rotational bands of sup 159 Yb

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:7253030

Courtney, L H

High-spin states in the transitional nucleus {sup 159}Yb were measured by means of heavy-ion induced reactions. The three reactions used were {sup 116}Cd({sup 48}Ti,5n){sup 159}Yb at 220 MeV, {sup 98}Mo({sup 64}Ni,3n){sup 159}Yb at 265 MeV, and {sup 147}Sm({sup 16}O,4n){sup 159}Yb at 90 MeV. The first two measurements were performed at the Holifield Heavy Ion Research Facility at Oak Ridge National Laboratory, using the Spin Spectrometer multi-detector array. The third reaction was performed at the McMaster University Tandem Accelerator Laboratory. The previously known i{sub 13/2} rotational band (Trautmann et al. 1975) has been extended up to 61/2 {Dirac h}, and possibly 69/2 {Dirac h}. Three new side bands have been established with spins and parities determined. All of the bands (structures) have been assigned intrinsic i{sub 13/2} and h{sub 9/2} neutron configurations. A systematic analysis of the neighboring transitional nuclei has been performed. The properties of these nuclei were compared at the 4-6 quasiparticle level, in order to learn about the shape-driving effects of quasiparticles at higher rotational frequencies. By contrast, earlier comparisons were done only at the 1-4 quasiparticle, level and at moderate rotational frequencies. Band crossings due to the rotational alignment of the secondary {nu}i{sub 13/2} pair and the primary {pi}h{sub 11/2} pair are seen in {sup 159}Yb. The primary neutron i{sub 13/2} crossing is not observed until after it has been completed. The crossing due to the secondary neutron pair and the proton pair are seen to be degenerate in the {nu}i{sub 13/2} band. In addition, a deficiency is observed in the alignment gain due to these two crossings. In order to understand these two features, Cranked Shell Model calculations and equilibrium shape calculations have been performed.

• Research Organization: Tennessee Univ., Knoxville, TN (USA)
• OSTI ID: 7253030
• Country of Publication: United States
• Language: English

Related Subjects

653001* -- Nuclear Theory-- Nuclear Structure
Moments
Spin
& Models
653003 -- Nuclear Theory-- Nuclear Reactions & Scattering
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CALCULATION METHODS
CHARGED-PARTICLE REACTIONS
DATA
ENERGY LEVELS
ENERGY RANGE
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HEAVY ION REACTIONS
HIGH SPIN STATES
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOTOPES
MEASURING INSTRUMENTS
MEASURING METHODS
MEV RANGE
MEV RANGE 100-1000
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
YTTERBIUM 159
YTTERBIUM ISOTOPES