Precise Validation of Database (n,) Cross Sections Using a Lead-Slowing-Down Spectrometer and Simulation from 0.1 eV to 30 keV: Methodology and Data for a Few Elements

Projects dealing with future reactors based on new fuels and able to incinerate nuclear waste require good knowledge of numerous cross sections. In order to resolve nuclear database discrepancies, capture cross-section profiles between 0.1 eV and 30 keV have been measured for different materials using a lead-slowing-down-time spectrometer in association with a pulsed neutron generator. The measurement of the neutron flux with a ²³³U fission detector and a ³He counter, and careful analysis of the E-t correlation compared to very precise Monte Carlo simulations, brought new information on the lead scattering cross section. Capture profiles for reference materials (gold, tantalum, indium, and silver), core materials (thorium and technetium), and structure materials (manganese and nickel) were measured with a CeF₃ scintillator and photomultiplier for different thicknesses. Areas of agreement and disagreement between experimental results and simulations using different databases have been determined with a precision of 5%. Correction tables are given for some elements. This method opens an efficient way for revisiting (n, ) databases, and it allows rapid error evaluation and sensitivity studies.