The absolute γ-ray/fission multiplicities from hot rotating ${}^{240}\mathrm{Cf},$ populated at seven bombarding energies using the reaction ${}^{32}{\mathrm{S}+}^{208}\mathrm{Pb},$ are reported. Statistical model calculations including nuclear dissipation have been performed to extract the dependence of the nuclear viscosity on temperature and/or nuclear deformation. The extracted nuclear dissipation coefficient is found to be independent of temperature. Large dissipation during the saddle to scission path provides a good fit to the γ-ray spectra.

• Received 8 December 1999

DOI:https://doi.org/10.1103/PhysRevC.61.044612