Measurement of Cross Sections for the Fission of the 239Pu and 240Pu Nuclei by 0.3–500-MeV Neutrons

Cross sections for the fission of 239 Pu and 240 Pu by 0.3–500-MeV neutrons have been measured on the time-of-flight spectrometer of the GNEIS neutron complex at the Petersburg Nuclear Physics Institute, National Research Center Kurchatov Institute. Fission fragments have been detected using low-pressure position-sensitive multiwire proportional counters. The 239 Pu( n , f ) and 240 Pu( n , f ) fission cross sections have been measured relative to the 235 U( n , f ) fission cross section. The obtained data are compared with the results of previous experimental works, as well as with cross sections from various libraries of evaluated data.