The neutron induced fission cross sections of ${}^{240,242}\mathrm{Pu}$ have been measured as a function of incident neutron energy from 1 eV to 200 MeV. This is part of an effort to reduce experimental uncertainties of nuclear data in support of next generation nuclear reactors and transmutation technology. These two plutonium isotopes are nonfissile, and the available data are limited below reaction threshold. The present data demonstrate the presence of a 2.67 eV resonance in the ${}^{242}\mathrm{Pu}$ fission cross section, which is missing in the ENDF/B-VII evaluation, and resolve discrepancies in the keV region. The measured cross sections are also compared with statistical model calculations made with the nuclear reaction code GNASH.

• Received 19 June 2008

DOI:https://doi.org/10.1103/PhysRevC.79.014613