Neutron emission in the fission of highly excited Californium nuclei (E*=72 MeV)

The differential cross-sections for neutron production in the fission of highly excited californium nuclei formed in the 238U+12C (105 MeV) reaction have been measured. From an analysis of the experimental data it follows that the number of pre-fission neutrons substantially exceeds the value obtained in the framework of the standard statistical model. The saddle-to-scission time of the excited nucleus is estimated on the basis of the neutron multiplicity. The dependences of the neutron number and their average energies on the fragment mass are determined. 22 refs.; 6 figs