Fission hindrance studies in 200Pb:: Evaporation residue cross section and spin distribution measurements

Evaporation residue cross sections and spin distributions have been measured for Pb-200 compound nucleus formed in O-16+W-184 reaction at the laboratory beam energies of 84, 92, 100, 108, 116, and 120 MeV. The evaporation residues have been selected using the recoil mass spectrometer, HIRA and detected using a 2D position sensitive silicon detector. The evaporation residue spin distributions have been measured by detecting gamma rays with 14 element BGO multiplicity filter. Measured evaporation residue cross sections and spin distributions are compared with the values predicted by a standard statistical model code. Comparison shows that, in the energy region studied, the nuclear viscosity parameter gamma=3 is required to explain total evaporation residue cross sections and evaporation residue spin distributions.