Nuclear viscosity of hot rotating 240Cf

The absolute {gamma}-ray/fission multiplicities from hot rotating {sup 240}Cf, populated at seven bombarding energies using the reaction {sup 32}S+{sup 208}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 {gamma}-ray spectra. (c) 2000 The American Physical Society.