$^{242}\mathrm{Pu}$ neutron-induced fission cross-section measurement from 1 to 2 MeV neutron energy

International audienceRelative values of the neutron-induced fission cross section σ(n,f) of 242Pu have been measured with respect to the standard 1H(n,p) elastic scattering cross section, at average energies of 1.0, 1.4, and 1.9MeV. The measurements are part of an international effort to reduce uncertainties and provide independent nuclear data relevant for fast-spectrum reactors. The shape of the measured cross section is in good agreement with data from Tovesson et al. [Phys. Rev. C 79, 014613 (2009)] and with the most recent data from Matei et al. [Phys. Rev. C 95, 024606 (2017)], but disagrees with the shapes of ENDF/B-VII.1 and JEFF3.2 evaluations. Absolute values of σ(n,f), obtained under some assumptions, indicate an overestimation of σ(n,f) in the evaluated libraries at 1.0 and 1.4MeV, while a good agreement is found with ENDF/B-VII.1 at 1.9MeV. A careful analysis of the impact of scattered neutrons and anisotropy of the fission fragment angular distribution has been performed. The measurement of the neutron flux by means of a proton-recoil detector is discussed. A comprehensive study of corrections applied to the data, of associated uncertainties, and of correlations between the measurements at the different energies is presented