Angular-momentum limitations in heavy ion-induced fusion reactions leading to sup 40 Ca and sup 42 Ca
Cross sections for the fusion of {sup 28}Si + {sup 12}C from 4.6 to 9.4 MeV/nucleon and {sup 30}Si + {sup 12}C from 5.2 to 8.3 MeV/nucleon have been measured. The bombarding energy covered in these experiments extends from the intermediate to high energy regimes of the fusion excitation function where the fusion cross section is known for most heavy ion-induced reactions to be decreasing. The decrease in the high energy fusion cross section is understood to be caused by a limitation imposed on the fusing system by the maximum angular momentum (l{sub cr}) the system can sustain. The mechanisms which determine the l{sub cr} for a particular projectile-target combination, or entrance channel, are however, not understood. It has been found that the characteristics of the entrance channel, rather than those of the compound nuclei {sup 40}Ca and {sup 42}Ca, determine the l{sub cr} for the {sup 28}Si + {sup 12}C and {sup 30}Si + {sup 12}C systems, respectively. The experiments were carried out with the time of flight apparatus at the Holifield Heavy Ion Research Facility at Oak Ridge National Laboratory. Beams of {sup 28}Si and {sup 30}Si ions were used to bombard {sup 12}C targets and complete or partial angular distributions for the heavy reaction products with atomic numbers from 24 to 40 were obtained at 6.4, 7.8, and 9.4 MeV/nucleon for {sup 28}Si + {sup 12}C and 5.2, 5.7, 6.4, 7.5, and 8.3 MeV/nucleon for {sup 30}Si + {sup 12}C. Charge and mass identification, combined with a kinematic analysis of the velocity distributions for individual isotopes, allowed separation of the yields from compound nucleus evaporation residues and nonfusion processes.
- Research Organization:
- Virginia Univ., Charlottesville, VA (USA)
- OSTI ID:
- 6998421
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HEAVY ION FUSION REACTIONS
CROSS SECTIONS
CALCIUM 40
CALCIUM 42
CARBON 12
EXPERIMENTAL DATA
MEASURING INSTRUMENTS
MEASURING METHODS
MEV RANGE
SILICON 28
ALKALINE EARTH ISOTOPES
CALCIUM ISOTOPES
CARBON ISOTOPES
DATA
ENERGY RANGE
EVEN-EVEN NUCLEI
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
SILICON ISOTOPES
STABLE ISOTOPES
700000* - Fusion Energy
700100 - Fusion Energy- Plasma Research