Recent measurements of the cumulative yields of essentially all the mass chains in the thermal neutron fission of U235 have enabled a detailed examination of the fine structure in the mass–yield curve. It has been found that most of the structure results from a slowly changing neutron yield as a function of the mass of the primary fission fragments.
The re-analysis of experimental data on mass measurements of ura- nium fission products obtained at the ESR in 2002 is discussed. State-of-the-art data analysis procedures developed for such measurements are employed.