Fissile Nuclei Rotation Effect in [sup 235]U(n,γf) Process

Abstract

A small shift of an angular distribution of prompt γ‐rays relative to the fission axis of 236U* 235U(n,γf) process is presented. This effect has been observed in the experiment at BER‐II reactor of BENSC/HMI (Berlin). The sign of the shift depends on the direction of the incident neutron beam polarization. This phenomena can be explained by the rotation of fissile nucleus 236U*, like the effect that has been observed recently at ILL in ternary fission of 235U by cold polarized neutrons. The main surprise of this result is the detection of scission gamma‐rays radiated by a fissile nucleus during the time interval of the order of 10−21 s before or after the moment of the neck rupture. Detailed measurements of trigger γ‐rays energy dependence are in progress at the neutron beam “MEPHISTO” of FRM‐II reactor (Garching).