Cascade-exciton model analysis of nucleon-induced fission cross sections of lead and bismuth at 45- to 500-MeV energies

An extended version of the cascade-exciton model (CEM) of nuclear reactions is applied to analyze nucleon-induced fission cross sections for Bi-209 an d Pb-208 nuclei in the 45- to 500-MeV energy range. The available data on l inear momentum transfer are analyzed as well. The results are compared with analytical approximations resulting from a comparative critical analysis o f all available experimental data. Systematic discrepancies between calcula tions and experimental data are revealed. A modification of the CEM is prop osed, which significantly improves the model predictions for projectile ene rgies above 100 MeV.