Fragment Angular Distribution for Neutron Fission of 232Th and 238U

The fragment angular distribution data are crucial to the interpretation of the sub-barrier resonances. Recently structure is reported in neutron induced fission fragment angular distributions of even-even actinide nuclei near threshold. The fission fragment angular distributions of $^{232}$Th and $^{238}$U exhibit considerable structure in the vicinity of fission threshold. The energy dependence of fission fragment angular anisotropies for $^{232}$Th (n, f) and $^{238}$U (n, f) reactions have been calculated in the frame work of statistical model. The results have been compared with existing experimental data taken from the library of experimental nuclear reaction data (EXFOR). We have found that the periodic structure of anisotropy related to the set of (n, xn) reaction is not extended beyond the threshold of (n,4n) reaction at incident neutron energy En$\sim $25MeV. Above this a smooth decrease of fragment anisotropies is observed at higher neutron energies, results will be presented and discussed.