Excitation energy dependence of fragment mass and total kinetic energy distributions in proton-induced fission of uranium isotopes

Nishinaka, Ichiro; Tanikawa, Masashi*; Goto, Shinichi*; Nishio, Katsuhisa   ; Asai, Masato  ; Tsukada, Kazuaki  ; Nagame, Yuichiro ; Kudo, Hisaaki*

The aim of this work is to study how shell effects of fissioning nuclei and fission fragments are responsible for deformation and mass division during descent from the saddle point to scission. We studied in detail excitation energy dependence of mass and total kinetic energy distributions in the fission of + U at incident beam energies of 10.0, 11.5 and 13.0 MeV. For the asymmetric mass division in the fission for both uranium isotopes, the obtained yield at 132 with the spherical shell of = 82 increases more largely with increasing excitation energy than that at 143 with deformed shell of = 86-88. The present excitation energy dependence shows the opposite trend observed in the thermal neutron induced fission and cold fission of actinides. We will discuss the shell effects on excitation energy dependence of fragment mass and total kinetic energy distributions in fission.