Neutron-induced fission cross-section of ²³³U in the energy range 0.5 < E_n < 20 MeV

The neutron-induced fission cross-section of U-233 has been measured at the CERN n_TOF facility relative to the standard fission cross-section of U-235 between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against alpha-particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n_TOF facility result in data with uncertainties of approximate to 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the U-233(n, f) cross-section and, consequently, the design of energy systems based on the Th/U cycle.