Fragment dependence of high energy gamma-ray emission in the spontaneous fission of Cf-252

The high energy gamma-ray emission accompanying the spontaneous fission of Cf-252 has been measured in coincidence with individual fission fragments s elected by discrete gamma-ray transitions. The enhancement of the gamma-ray emission probability in the energy range E-gamma=3-8 MeV has been observed for the fission fragments in the region of nearly symmetric mass splitting , confirming results reported in previous investigations. The gamma-gamma c oincidence technique employed in the present work clearly demonstrate that the major contribution to this enhancement is caused by the fission channel s where one fragment is near to the N=82 or Z=50 shell closures. The high e nergy gamma-ray emission probability does not show any significant dependen ce on the number of neutrons emitted in the fission process, supporting the hypothesis that high energy gamma-rays are mainly emitted from the fragmen ts after the neutron evaporation.