Quasi-absolute neutron-induced fission cross section of 243Am

The existing evaluations of the 243Am neutron-induced fission cross section have been questioned by recent studies 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 performed a first quasi-absolute measurement of this fission cross section from the fission threshold up to the onset of second-chance fission. To achieve this goal we have used the neutron-proton scattering cross section as reference reaction to determine the incident neutron flux since this cross section is known with a precision better than 1% for a wide range of neutron energies (1 meV to 20 MeV). Our results are in agreement with the international evaluations JENDL-3.3 and Endf-B6, and the data of Knitter et al. Consequently, our results indicate that the latest results of Laptev et al. over-predict the 243Am neutron-induced fission cross-section. The overall precision of our data is of 4 per cent