New evidence of an intense scission neutron source in the 252Cf spontaneous fission

Abstract The neutron energy-angular distributions relative to the fragment direction of 252 Cf (SF) were analysed. The results of three independent experiments being in reasonable agreement allows the conclusion that a (30±5)% neutron surplus exists at ∼90 ∘ relative to the direction of the moving fragments, which can not be accounted for with the assumption that all neutrons are emitted from fully accelerated fragments. This experimental fact required the incorporation of neutron emission from an additional source of neutrons. Angular and energy distributions of these additional neutrons were evaluated using data from an experiment performed at IRMM several years ago and were compared with the results in literature.