Langevin fluctuation-dissipation dynamics of hot nuclei: Prescission neutron multiplicities and fission probabilities

• Published in: Nuclear physics. A Vol. 556; no. 2; pp. 281 - 306
• Main Authors: Fröbrich, P., Gontchar, I.I., Mavlitov, N.D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10.05.1993
• ISSN: 0375-9474
• DOI: 10.1016/0375-9474(93)90352-X

We combine a dynamical (Langevin) and statistical description of heavy-ion induced fission in a model which also includes the evaporation of light particles (n, p, α, d, giant-dipole γ's), and apply it systematically to the data. In the dynamical and statistical parts of our approach important modifications — as compared with the conventional approach — are introduced. In both parts the crucial role is played by the entropy, which is constructed from a deformation-dependent level-density parameter, and a dependence on the scission point is introduced in the statistical-model part. The new model turns out to be fairly universal (no input parameter is readjusted for a particular system) and reproduces satisfactorily experimental prescission neutron multiplicities and fission probabilities for a wide range of systems and excitation energies. We extract information on the deformation dependence of the level-density parameter, the nuclear friction coefficient, and on the time scale of the fission process.