Precise validation of database (n,$\gamma$) cross sections using a lead-slowing-down spectrometer and simulation from 0.1 eV to 40 keV : Methodology and data for a few elements

Research on accelerator driven systems (ADS), related new fuels and their ability for nuclear waste incineration has led to a revival of interest in nuclear cross sections of many nuclides over a large energy range. Discrepancies observed between nuclear data bases require new measurements in several cases. A complete measurement of such cross sections including resonance resolution consists of an extensive beam time experiment associated to a long process of analysis ans validation. With a slowing down spectrometer associated to a pulsed neutron source, it is possible to determine good cross section profile in an energy range from 0.1 eV to 40 keV. These measurements performed at ISN (Grenoble) with neutron source GENEPI requires only small quantities of matter (as small as 0.1 g) and about one day of beam per target.