RESOLUTION OF THE ANOMALOUS FISSION FRAGMENT ANISOTROPIES FOR THE O-16-208 REACTION(PB)

Fission and evaporation residue cross sections and fission fragment an gular distributions have been measured for the reaction O-16 + Pb-208 in small energy steps spanning the barrier region. Fission fragment an isotropies have been calculated using the transition state model, maki ng use of spin distributions more accurately determined from the new c ross-section data, and a more realistic calculation of the nuclear tem peratures at the saddle-point. Comparison of these calculations with t he new experimental anisotropies show no evidence for anomalously larg e fission fragment anisotropies at beam energies below the average fus ion barrier. Thus, the standard models of fusion and fission are able to describe the new data.