Fusion, transfer, and elastic scattering at sub-barrier energies for /sup 16,18/O ions on /sup 208/Pb and /sup 15/N and /sup 16/O ions on /sup 209/Bi

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

DOI:https://doi.org/10.1103/PhysRevC.33.2017· OSTI ID:5609846

Vulgaris, E; Grodzins, L; Steadman, S G; Ledoux, R

The fusion of the heavy asymmetric systems of /sup 16/O, /sup 18/O+ /sup 208/Pb and /sup 15/N, /sup 16/O+ /sup 209/Bi was studied at bombarding energies near and below the Coulomb barrier. The fusion-fission, transfer, and elastic angular distributions were measured for all four systems. The evaporation residue component of the fusion was measured for only the /sup 16/O+ /sup 208/Pb..-->.. /sup 224/Th reaction; in agreement with statistical model calculations, the cross section for the evaporation residues was found to be negligible compared to the fission, and hence can be ignored in all the systems. The shapes of the fission fragment angular distributions are then a direct measure of the entrance channel spins which lead to fusion. The experimental sub-barrier fusion cross sections are underpredicted by the one-dimensional barrier penetration model in all cases. However, if the zero point motion of the targets is included in the barrier penetration model, the energy dependence of both the total fusion and the fission angular distributions can be explained for the /sup 15/N+ /sup 209/Bi system alone. To fit the low-energy fusion of the oxygen reactions requires considerably more zero point motion: this being inconsistent with the fact that this effect should be the same in all the reactions. Also, the cross sections measured for the transfer channels were found to exhibit the same trend as the fusion at the lower energies. This correlation suggests that some of the sub-barrier fusion in the oxygen-induced reactions may be due to transfer-related processes.

• Research Organization: Laboratory for Nuclear Science and Physics Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
• DOE Contract Number: AC02-76ER03069
• OSTI ID: 5609846
• Journal Information: Phys. Rev. C; (United States), Vol. 33:6
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BISMUTH 209 TARGET
NITROGEN 15 REACTIONS
OXYGEN 16 REACTIONS
LEAD 208 TARGET
OXYGEN 18 REACTIONS
ELASTIC SCATTERING
HEAVY ION FUSION REACTIONS
TRANSFER REACTIONS
FISSION
ANGULAR DISTRIBUTION
COMPOUND-NUCLEUS REACTIONS
COULOMB FIELD
CROSS SECTIONS
DEFORMED NUCLEI
EVAPORATION MODEL
EXPERIMENTAL DATA
MULTIPLICITY
SHELL MODELS
STATISTICAL MODELS
CHARGED-PARTICLE REACTIONS
DATA
DIRECT REACTIONS
DISTRIBUTION
ELECTRIC FIELDS
HEAVY ION REACTIONS
INFORMATION
MATHEMATICAL MODELS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
SCATTERING
TARGETS
651925* - Nuclear Properties & Reactions
A=190-219
Experimental- Nuclear Reactions & Scattering- (-1987)