A novel formulation of the dependence of the total cross section for the photon-nucleus interaction on photon energy and target mass number is proposed and used to obtain the photofission channel width rF for 238U in the quasideuteron energy range. Comparison with experiments and with different calculations show that the formalism used is quite adequate to explain the generally assumed trend of rF against energy and mass number in this peculiar energy region.NUCLEAR REACTION 238U ( y , Fission), 40 M e V s E,< 80 MeV; calculated total cross section, uT, and fission channel width, rF. Comparison with experimental and calculated values of rF for different interaction models.