TOTAL AND NUCLEAR-FISSION CROSS-SECTIONS OF U-238 AT RELATIVISTIC ENERGIES

Total fission cross sections of U-238 projectiles were measured at bom barding energies of 0.6 and 1 GeV per nucleon for seven different targ ets (Be, C, Al, Cu, In, Au, and U). It is found that all data points f all onto one curve, independent of bombarding energy, once the electro magnetic contribution to the total fission cross sections is subtracte d. The abrasion-ablation model predicts a significantly weaker target dependence than observed, and underestimates the nuclear fission cross sections for the heavier targets.