Spin distribution of the compound nucleus in heavy ion reactions at near-barrier energies
Gamma ray multiplicities and the (HI,xn) cross sections for the dominant reaction channel were measured at near-barrier bombarding energies for the systems ..cap alpha.. (15 to 24 MeV) + /sup 154/Sm and /sup 12/C (46 to 61 MeV) + /sup 154/Sm. The mean value of the spin distribution of the compound nucleus was obtained for each of the systems studied. The results of these measurements together with the results of an earlier study on /sup 16/O + /sup 154/Sm 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 of the three systems clearly indicates the importance of the centrifugal barrier penetrability in determining the spin distribution of the compound nucleus. The absolute values of the mean angular momentum can be accounted for if one also includes deformation effects. A one-dimensional barrier-penetration model including the effect of averaging over the orientation of the deformed target can account for the experimental results. 29 references.
- Research Organization:
- Washington Univ., Seattle (USA)
- DOE Contract Number:
- AC06-81ER40048
- OSTI ID:
- 5966730
- Report Number(s):
- DOE/ER/40048-118-L4; ON: DE85007846
- Country of Publication:
- United States
- Language:
- English
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Spin distribution of the compound nucleus in heavy ion reactions at near-barrier energies
Spin distribution of the compound nucleus in heavy ion reactions at near-barrier energies
Related Subjects
ALPHA REACTIONS
COMPOUND-NUCLEUS REACTIONS
FUSION REACTIONS
CARBON 12 REACTIONS
COMPOUND NUCLEI
SPIN
SAMARIUM 154 TARGET
ANGULAR MOMENTUM
COULOMB ENERGY
CROSS SECTIONS
ENERGY DEPENDENCE
EXPERIMENTAL DATA
GAMMA RADIATION
HEAVY ION REACTIONS
MEV RANGE 10-100
MULTIPLICITY
MULTIPOLE TRANSITIONS
NUCLEAR DEFORMATION
THEORETICAL DATA
CHARGED-PARTICLE REACTIONS
DATA
DEFORMATION
ELECTROMAGNETIC RADIATION
ENERGY
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
INFORMATION
IONIZING RADIATIONS
MEV RANGE
NUCLEAR REACTIONS
NUMERICAL DATA
PARTICLE PROPERTIES
RADIATIONS
TARGETS
651825* - Nuclear Properties & Reactions
A=150-189
Experimental- Nuclear Reactions & Scattering- (-1987)