Fission time in the 28Si + natPt reaction

The experimental fission times are analyzed for excited nuclei produced in the ²⁸Si + ^natPt reaction. Experimental lifetimes obtained by the crystal-blocking technique range between 10^?17 and 10^?18 s at bombarding energies between 140 and 170 MeV, respectively. Experimental data are analyzed within the statistical theory of nuclear reactions and the double-humped-fission-barrier model with allowance for preequilibrium processes and the nuclear-dissipation phenomenon. It is shown that fission barriers retain their double-humped structure for nuclear temperatures up to about 1.7–1.8 MeV and that the lifetimes of excited strongly deformed states in the second potential well contribute substantially to the observed delay times in the fission decay channel.