The fission fragment angular distributions for spontaneous fission of aligned nuclei and the problem of the conservation of spin projection onto symmetry axis of fissile nucleus

The transitional fission state concept successfully used for description of the fragments' angular distributions (FAD) for spontaneous and low-energy induced fission of axial-symmetrical nuclei is correct if the spin projection of fissile nucleus (SPFN) onto its symmetry axis is the integral of motion for external region from the descent of fissile nucleus from external fission barrier to scission point. By heating of fissile nucleus in this region to the temperature T≅1 MeV, predicted by a lot of theoretical fission models, the Coriolis interaction uniformly mixes possible SPFN for a case of small spin values that leads to forgetting of the transitional fission states in asymptotical region where FAD are formed. In the frame of quantum-mechanical fission theory taking into account the deviations from A.Bohr's formula the FAD for spontaneously fissioning nucleus aligned by external magnetic field for superlow temperatures are calculated and it is shown that the analysis of the named FAD gives the possibility to solve the problem of SPFN conservation for external region