U²³⁸-Spaltung mit 14 MeV Neutronen

Abstract

A measurement on the reaction U²³⁸(n,f) with 14 MeV neutrons has been done. The energies of the two fission fragments were analyzed in coincidence using Si surface detectors. The angle between incident neutron and outgoing fragment direction was set to 0° and 90° in the laboratory system. Some 2300 events have been recorded. The resultant mass distribution is in fairly well agreement with radiochemical data. The average kinetic energy release before prompt neutron emission has been found to beĒ=(160,8±4) MeV. For symmetric fission a kinetic energy dip has been observed. The anisotropy α in the postulated angular distributionW(Θ)=1+α cos² Θ is strong dependent on mass ratio, being positive and greatest for asymmetric fission. The value of α averaged over all mass ratios, ¯α=0,33±0,07, compares well with already published data. The results are discussed in terms of new fission models.