An experimental investigation of fission

Accurate measurements have been made of the average number of prompt neutrons, emitted per fission for thermal neutron fission of U233, U235, Pu239 and Pu241 and spontaneous fission of Pu240 and Pu242. The large liquid scintillator method has been used and sources of error in this method have been closely examined. In addition, precise measurements have been made of the probability distribution of neutron emission for each of the six cases above and the spontaneous fission of Cf252. The data have been compared with the neutron emission distribution calculated from fragment kinetic energy data.