243Am neutron-induced fission cross section in the fast neutron energy range

Abstract

The existing evaluations of the ${}^{243}$Am neutron-induced fission cross section have been questioned by recent measurements performed at the GNEISS facility. In the neutron energy range from 1 to 6 MeV, the GNEISS data present deviations of more than 15$%$ with respect to the evaluations. In order to solve this problem, we have measured this cross section in reference to three different standard cross sections. The first standard reaction used corresponds to the neutron on proton elastic scattering cross section, which is known with a precision better than 0.5$%$ over a wide neutron-energy range of 1 meV to 20 MeV. The other two experiments were conducted in reference to the ${}^{235}$U(n, f) and ${}^{238}$U(n, f) reactions. The comparison between these three standard reactions ensures that systematic parameters have been correctly evaluated. Moreover, a sensitivity analysis of parameters and correlations of parameters is described and a complete variance-covariance matrix of the measurements is presented and discussed.