Variation of kinetic energy distributions of fission fragments with bombarding energy in 4He induced fission of 238U at medium energies

The kinetic energy and mass distributions of fission fragments in 4He induced fission of 238U were studied in the bombarding energy range of 32 to 56 MeV. The variation in the average fragment kinetic energy anti Ek with bombarding energy has been obtained as a function of fragment mass. It is seen that anti Ek increases strongly with bombarding energy and the slope danti Ek/dEα has a strong dependence on the fragment mass. This result indicates that both the shell effects and the saddle to scission dynamics may play a role in determining the scission configuration at these excitation energies. (orig.)