Experimental studies of nuclear fission dynamics near the scission point

Measurements of angular and energy distributions of prompt neutrons from thermal neutron-induced fission

“…ðE cm Þ 1=2 cosðy cm Þ ¼ ðE n Þ 1=2 cosðy lab Þ À ðE f Þ 1=2 (15) where A is the mass number of the fissioning nucleus, m f and TKE are the initial fragment mass and total kinetic energy of fission fragments, respectively. The number of neutrons n(E n ,y) with energy E n per unit energy range and solid angle, registered at angle y with respect to the direction of motion of light fragments in the laboratory coordinate system, can be written as a sum of prompt neutrons emitted from light n L (E n ,y) and heavy n H (E n ,180Ày) fragments: nðE n ; yÞ ¼ nLðE n ; yÞ þ nHðE n ; 180 À yÞ.…”

“…The experimental set-up [15,16] shown in Fig. 1 was installed at the radial neutron channel N7 of the research reactor WWR-M equipped with a neutron guide 3 m in length.…”

Nuclear spin-orbit interaction and T-odd angular correlations in ternary fission

“…However, for some other target nuclei one may expect the opposite situation: W 1 is suppressed, W 2 dominates, then D 13 ≃ −D 24 in casual accordance with the semiclassical picture. The surprising thing is that this was found in the latter half of 2000 in ternary fission of nuclei 235 U by slow neutrons [8,9] ! Unfortunately, the scepticism with respect to the spinorbit model has not been revised.…”

“…Unfortunately, the scepticism with respect to the spinorbit model has not been revised. The authors of [8,9] related the new type of asymmetry with nuclear "rotation" before scission and labelled it as "ROT effect". Shorter label "R-effect" seems more preferable and will be used in what follows.…”

“…It should be emphasized that Eqs. ( 1)-( 4) describe both T-effect and R-effect, but they has been obtained in [6] before the measurements [8,9] were performed. In the general case, the contributions from W 1 and W 2 can be of the same order (both T-effect and R-effect will be observed).…”