Fragment Anisotropy of Complete Fusion-Fission at Subbarrier Energies for the ¹¹B+²³⁸U and ¹²C+²³⁷Np Reactions

Fission fragment angular distributions have been measured for the reactions ¹¹B+²³⁸U, ¹²C+²³⁷Np at near- and sub-barrier energies, and ¹⁶O+²³⁸U at 90MeV. The complete fusion-fission and transfer-fission were separated as components in the whole energy region in this experiment. The influence of pre-scission neutron emission on fragment anisotropies has been considered. This effect leads to increase of the anisotropies when compared with the results obtained under the assumption of first chance fission. However, the anomalous anisotropies still persist.