Angular momentum in sub-barrier fusion: Experimental study using the isomer ratio sup 137 Ce sup m / sup 137 Ce sup g

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.42.2108· OSTI ID:6394433

DiGregorio, D E; Lesko, K T; Harmon, B A; Norman, E B; Pouliot, J; Sur, B; Chan, Y; Stokstad, R G ^[1]

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1. Nuclear Science Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA (USA)

The ratio of the yields for the isomer ({ital J}{sup {pi}}=11/2{sup {minus}},{ital t}{sub 1/2}=34.4 h) and ground state (3/2{sup +}, 9.0 h) of {sup 137}Ce populated in the reactions {sup 128}Te({sup 12}C,3{ital n}), {sup 133}Cs({sup 7}Li,3{ital n}), {sup 136}Ba({sup 3}He,2{ital n}), {sup 136}Ba({sup 4}He,3{ital n}), and {sup 137}Ba({sup 3}He,3{ital n}) were measured from energies above the Coulomb barrier to energies typically 20--30% below the barrier by observing the delayed x- and {gamma}-ray emission. In the first three reactions we observed an approximately constant value for the isomer ratio at energies far below the barrier. This indicates an approximately constant average angular momentum at low bombarding energies. We analyze isomer ratios and cross sections using a coupled-channels model for the fusion and a statistical model for the decay of the compound nucleus. Absolute values of the angular momentum {ital {bar J}} in the entrance channel are deduced from the isomer ratio. The values of {ital {bar J}} exhibit the behavior predicted for low energies and the expected variation with the reduced mass of the entrance channel.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6394433
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Vol. 42:5; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
HEAVY ION FUSION REACTIONS
BARIUM 136 TARGET
HELIUM 3 REACTIONS
BARIUM 137 TARGET
CARBON 12 REACTIONS
CERIUM 137
ISOMER RATIO
CESIUM 133 TARGET
LITHIUM 7 REACTIONS
TELLURIUM 128 TARGET
ANGULAR MOMENTUM
BETA DECAY
COUPLED CHANNEL THEORY
CROSS SECTIONS
STATISTICAL MODELS
BETA DECAY RADIOISOTOPES
CERIUM ISOTOPES
CHARGED-PARTICLE REACTIONS
DAYS LIVING RADIOISOTOPES
DECAY
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
HEAVY ION REACTIONS
HOURS LIVING RADIOISOTOPES
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MATHEMATICAL MODELS
NUCLEAR DECAY
NUCLEAR REACTIONS
NUCLEI
RA
RADIOISOTOPES
RARE EARTH ISOTOPES
TARGETS
651720* - Nuclear Properties & Reactions
A=90-149
Experimental