engleski

DYNAMIC-STATISTICAL APPROACH TO THE DESCRIPTION OF THE INDUCED FISSION IN WIDE EXCITATION ENERGY RANGE

It is developed a new approach to analyze the induced fission of heavy nuclei, which takes into account the nuclear dissipation phenomenon and the shell structure of nuclei in determination of fission barriers. The approach is based on the combined dynamical and statistical simulations. In the framework of this approach the method of calculation the fission fragment angular distributions in a wide energy range is discussed. The ability of the method is demonstrated in the simultaneous description of the experimental data of the fission probabilities on the Am and Pu nuclei, yields of the spontaneous fission of isomers for the alpha + (238)U reaction at E(alpha) = (20 - 32) MeV and the d + (242, 240)Pu reactions at E(d) = (20 - 30) MeV, the fission times for the alpha + (238)U reaction and angular distribution of fission fragments for the alpha + (238)U, (237)Np reactions at E(alpha) = (20 - 100) MeV. A further information on the value of the nuclear dissipation at low excitation energies is obtained. In addition, it is demonstrated that the influence of the shell effects on the deformation potential energy holds up to excitation energies of about (50 - 60) MeV.

FRAGMENT ANGULAR-DISTRIBUTIONS ; ALPHA-PARTICLES ; EXCITED-STATES ; NUCLEI ; MODEL

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