Rotation effect of a fissile nucleus (ROT effect) for prompt <i>γ</i>-rays in binary fission of ²³⁵U by polarized neutrons of different energies*

Abstract This article describes a series of studies on the effect of the rotation of the fissile 236 U nucleus in the 235 U( n , f ) process induced by monochromatic polarized neutrons with energies of 62 meV and 270 meV. The studied effect is expressed as a shift in the anisotropic angular distribution of γ -rays emitted by excited fission fragments by a small angle relative to the deformation axis of the fissile nucleus when the neutron beam polarization direction is reversed. All measurements were performed at the Heinz Mayer-Leibniz research neutron source (FRM II reactor) of the Munich Technical University in Garching on the polarized neutron beam of the POLI instrument. To generalize all results obtained on ROT effects for fission γ -rays, the results of earlier studies by the ITEP group for cold neutrons are re-processed, and the result obtained by the PNPI group for thermal neutrons is also presented.