Peculiarities of mass and energy distributions of fragments from /sup 235/U and /sup 236/U fission induced by alpha particles of moderate energies (< or =80 MeV)

Many-parameter measurements of mass and energy distributions of fragments from /sup 235/U and /sup 236/U fission induced by 20--80 MeV alpha particles are carried out making use of the correlation method. Variation of characteristics of the fragment mass distributions with variation of E* is discussed. The energy dependence of the cross sections of symmetric and asymmetric fission is obtained in absolute units. The energy dependence of the cross section ratio sigma/sub s//sigma/sub a/ is analysed in the framework of the statistical model. The analysis results show that at excitation energies above 40 MeV the difference between fission barriers for symmetric and asymmetric fission is substantially reduced.