Simultaneous Measurement of the Neutron Fission and Absorption Cross Sections of Plutonium-239 Over the Energy Region 0.02 eV to 30 keV

The neutron absorption and fission cross sections for ²³⁹Pu have been measured simultaneously over the neutron energy range from 0.02 eV to 30 keV. These cross sections were measured using an ionization chamber containing ²³⁹Pu. The differential cross sections derived from these measurements are presented along with a multilevel analysis of the data up to 100 eV. A reevaluation of data obtained using a metal foil of ²³⁹Pu has also been made. Average values of the neutron capture and fission cross sections are presented for ²³⁹Pu as obtained using the ionization chamber as well as with the metal foil. A detailed comparison of the present data is made with the results of the ENDF/B evaluation for ²³⁹Pu (material 1104). The neutron cross sections presented in this report supersede the results reported previously by the authors of this report.