Heavy-ion-induced fission following fusion. [Review]

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6058893

Plasil, F.; Ferguson, R. L.

Theoretical considerations of fission of systems with high angular momenta are usually made in the framework of the rotating liquid drop model. The most stringent tests of this theory involve studies of excitation functions for evaporation residue products. At present there is no evidence for the survival of any rotating system which is predicted not to have a fission barrier. The extent to which the vanishing fission barrier imposes a limit on evaporation residue cross sections will be discussed in this review with reference to several cases, ranging from very light systems, such as /sup 14/N + /sup 12/C to medium mass systems, such as /sup 86/Kr + /sup 65/Cu. The prevalence of deeply inelastic processes in heavy ion reactions poses a problem for arriving at an operational definition of heavy-ion-induced fission. This in turn makes it difficult to define fusion of complex nuclei. While some yield at symmetric mass divisions is usually observed and while the products in this region often have fission-like kinetic energies and even angular distributions, indications are that in most cases tails of strongly damped distributions are involved, rather than the fusion--fusion process. In some cases, there is strong evidence for the existence of a separate and distinct fission component. When excitation functions for both evaporation residue products and for well-characterized fission fragments are available, it is possible to carry out a statistical model analysis and extract values of the fission barrier. Beckerman and Blann have carried out such analyses and concluded that liquid drop fission barriers must be reduced by approximately 40% to reproduce experimental results. A critical appraisal of this conclusion is given. New results are introduced on data allowing a very stringent test of the theory of angular-momentum dependence of fission barriers. 40 references.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6058893
• Report Number(s): IAEA-SM-241-D1; CONF-790507-3
• Country of Publication: United States
• Language: English

Related Subjects

653006* -- Nuclear Theory-- Spontaneous & Induced Fission
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
ANGULAR MOMENTUM
BETA DECAY RADIOISOTOPES
CARBON 12 REACTIONS
CESIUM 133 TARGET
CHARGED-PARTICLE REACTIONS
CHLORINE 35 REACTIONS
CROSS SECTIONS
DATA
DATA FORMS
DAYS LIVING RADIOISOTOPES
DEEP INELASTIC SCATTERING
DISTRIBUTION
DOCUMENT TYPES
ELECTRON CAPTURE RADIOISOTOPES
ENERGY
EVAPORATION MODEL
EXCITATION FUNCTIONS
EXPERIMENTAL DATA
FISSION
FISSION BARRIER
FUSION REACTIONS
GRAPHS
HEAVY ION REACTIONS
INELASTIC SCATTERING
INFORMATION
INTERACTIONS
INTERMEDIATE MASS NUCLEI
ISOTOPES
KINETIC ENERGY
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
LIQUID DROP MODEL
MATHEMATICAL MODELS
MOTION
NEON 20 REACTIONS
NUCLEAR MODELS
NUCLEAR POTENTIAL
NUCLEAR REACTION YIELD
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
PARTICLE INTERACTIONS
POTENTIALS
PRASEODYMIUM 141 TARGET
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
REVIEWS
ROTATION
SCATTERING
SILVER 107 TARGET
STATISTICAL MODELS
TARGETS
TERBIUM 153
TERBIUM ISOTOPES
TIN 116 TARGET
YIELDS