Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN – n_TOF

The U-238 fissioncross section is an international standard beyond 2 MeV where the fissionplateau starts. However, due to its importance in fissionreactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The U-238 fissioncross section has been measured relative to the U-235 fissioncross section at CERN - n_TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards.