Electromagnetic fission cross sections of a 120 MeV/nucleon ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ beam incident on five targets, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Ag}$, and ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{U}$, have been extracted from measurements of projectile velocity fission fragments. The nuclear interaction contributions to the experimentally observed cross sections were determined by extrapolation from the Be target data using a geometrical scaling model and by an empirical decomposition of the fission charge distributions. The results are compared to model calculations in which electric quadrupole excitations have been included.

• Received 2 June 1993

DOI:https://doi.org/10.1103/PhysRevC.49.R5