FRAGMENT PROPERTIES AND VALLEY STRUCTURE OF THE U-237 FISSION BARRIER

The results of multidimensional analysis of the properties of fragment s of fission of U-236 induced by 1-MeV neutrons are presented. A doubl e ionization fission chamber with Frisch grids was used. The measureme nt method and details of the data analysis are described in detail. Th e average and differential properties of the fragments were observed t o exhibit details reflecting the fine structure of the potential-energ y surface of the fissioning nucleus. The cold-fragmentation spectra of uranium are analyzed. Global changes of the angular distributions of the fragments with increasing separation of the scission point from th e saddle configuration are established. They can be explained by nonco nservation of the quantum number K in the fission process resulting fr om the effects of viscosity, admixture of a vibration resonance, or se paration in K at the so-called scission barrier between the fission an d fusion valleys.