Characteristics of Coulomb fission

Hans Kruse and William T. Pinkston Department of Physics, Vanderbilt Uniuersity, Nashuille, Tennessee 37235 (Received 23 February 1979) Within an extended semiquantal theory we perform large-sized coupled-channel calculations involving 260 collectiue .levels for Coulomb fission of 238U. Differential Coulomb fission cross sections are studied as a function of bombarding energy and impact Parameter for several projectiles. In the Xe + U case, total cross sections are also given. We find a strong dependence on projectile charge number, fCF(18q (Zp)6 in the region 50 52, 92 for a fixed ratio E/Ecod, which might be helpful to separate Coulomb fission experimentallyfrom sequential fission following transfer reactions. Since the cross sections are sensitive to the moment of inertia O at the saddle point, Coulomb fission can serve as a tool to investigate the dependence of O on elongation. The fragment angular distribution exhiblts deviations from l/sinOf which are pronounced at low incident energies. Our theory indicates that the recently measured Xe + U fission cross sections contain a major fraction of Coulomb-induced fission at E 5 0.85 E„„.