ANGULAR DISTRIBUTIONS OF FISSION FRAGMENTS AND THE SHAPES OF THE SADDLE POINT OF COMPOUND NUCLEI

We have measured the angular distributions of fission fragments for a series of compound nuclei formed in the bombardment of ¹⁶⁹Tm, ¹⁷⁵Lu, ¹⁸¹Ta, ¹⁹⁷Au, ²⁰⁹Bi, ²³²Th and ²³⁸U by 78 MeV ¹²C ions and in the bombardment of natural lead by 96.6, 92.2, 88.1, 79.0 and 75.6 MeV ¹⁴N ions with mica track detectors. All the measured angular distributions can be fitted by the theoretical formula given by Halpern and Strutinski. The effective moments of inertia of the fissioning nuclei at the saddle point are derived from the angular distribution anisotropies. A comparison is made for the shapes of experimental saddle point with the theoretical predictions by the liquid drop model.