Speaker
Description
In [1–2], the coefficients of P-even T-odd asymmetries in the cross sections for nu-clear fission reactions by cold polarized neutrons with the emission of light particles p were found, expressed in terms of experimental particle count rates p in coincidence with light fission fragments for the directions of polarization vector either along or against the Y axis. For the theoretical description of these coefficients in the case of -particles us-ing the semiclassical method of trajectory calculations, the formula [1] (1) was proposed. Its first term, expressed through the rotation angle , took into account the influence of the Coriolis in-teraction of the spin of a compound fissile system (CFS) rotating around an axis perpendicular to its symmetry axis on the angular distributions of both fission fragments ( ) and -particles ( ). The appearance of the second term in (1) was based on the hypothesis [1] about the change in the angular distribution of -particles under the action of the Coriolis interaction associated with the collective rotation of the CFS around the fission axis, which turns out to be possible when the axial symmetry of the CFS is violated due to taking into ac-count its collective transverse oscillations, in the vicinity of the rupture point. The coefficients calculated in [1] using formula (1), for the positive values of the angles found in the trajectory method, turned out to be in satisfactory agreement with the corresponding ex-perimental coefficients [1] for target nuclei 233U, 235U, 239Pu и 241Pu. Formula (1) can be generalized to the case of emission of evaporative neutrons and -quanta, taking into account the fact that the influence of two types of Coriolis interaction on the angular distribu-tions of these particles can be neglected, since these interactions are small at the moment of emission of evaporative particles due to very large values of the moment of inertia CFS. This leads to the exclusion of the quantity in (1) and the replacement of the angle by the angle . The coefficients calculated using the obtained formula turned out to be in satisfactory agreement with similar experimental coefficients from [2] in the case of the 235U target nucleus, but has opposite signs for the 233U target nucleus. The last result demontrates the need to look for an alternative approach to the description of the coefficients , different from the semiclassical approach.
| The speaker is a student or young scientist | No |
|---|---|
| Section | 2. Experimental and theoretical studies of nuclear reactions |
