Preequilibrium fission for low angular momentum

We have compared the fragment anisotropies of 11B + 237Np and 16O + 232Th which both populate the same fissioning system 248Cf. The data clearly show the evidence of the entrance-channel dependence of fission-fragment anisotropies. A new version of the preequilibrium fission model is put forward. In the framework of this model, the discrepancy between the experimental mean-square angular momentum 〈J2〉exp. and the prediction of the coupled-channels model, 〈J2〉theory is reasonably removed.