Spin distribution of the compound nucleus in heavy ion reactions at near-barrier energies

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5769474

Gil, S

..gamma..-ray multiplicities and the (HI,sn) cross section for the dominant reaction channel were measured at near-barrier bombarding energies for the systems ..cap alpha.. + /sup 154/Sm, /sup 12/C + /sup 154/Sm, and /sup 16/O + /sup 154/Sm. From these experimentally measured quantities, the first two moments of the spin distribution of the compound nucleus were obtained for each of the systems studied. Our measurements indicate that at bombarding energies near and below the Coulomb barrier the spin distributions of the compound nucleus are broader than the triangular distributions expected from a sharp cutoff model, these deviations being larger for the more massive projectiles. The different behavior among the three systems studied clearly indicates the relevance of the centrifugal barrier penetrability in determining the spin distribution of the compound nucleus. In all the systems studied the authors used the same target and therefore the contribution of the deformation to the broadening is expected to remain constant. It was also found that the one dimensional barrier-penetration model including deformation can account for the experimental results very nicely. The success of these models together with their simplicity make the barrier-penetration models very useful for predicting spin distributions in this mass region. The degree of agreement between our experimental results and the theoretical predictions also suggest that the assumption of regarding the effective inertia parameter of the system as the reduced mass of the entrance channel is adequate in these cases. Moreover the reduced mass of the entrance channel accounts quite well for the variation found in the behavior of the different systems used in this work.

• Research Organization: Washington Univ., Seattle (USA)
• OSTI ID: 5769474
• Country of Publication: United States
• Language: English

Related Subjects

651825* -- Nuclear Properties & Reactions
A=150-189
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
ANGULAR MOMENTUM
CARBON 12 REACTIONS
CHARGED-PARTICLE REACTIONS
COMPOUND-NUCLEUS REACTIONS
COULOMB FIELD
DATA
DISTRIBUTION
ELECTRIC FIELDS
ENERGY RANGE
EXPERIMENTAL DATA
HEAVY ION REACTIONS
INFORMATION
MEV RANGE
MEV RANGE 100-1000
NUCLEAR REACTIONS
NUMERICAL DATA
OXYGEN 16 REACTIONS
PARTICLE PROPERTIES
SAMARIUM 154 TARGET
SPIN
TARGETS