Benchmark analyses of the ENDF/B-VI, EFF-1 and EFF-2 beryllium data evaluations for neutron transport calculations

The beryllium data evaluations by Perkins et al. (ENDF/B-VI), Field et al. (EFF-2) and Young and Stewart (EFF-1) are analysed with regard to their use in neutron fusion applications. There are considerable differences in the secondary energy and angle distributions with a strong impact on the neutron transport in beryllium. For EFF-2 and ENDF/B-VI data there are severe discrepancies with measured double-differential cross-sections at several energies and angles. A preference for the EFF-1 beryllium data can be deduced from the analysis of transmission experiments on spherical beryllium assemblies with measurements of the neutron leakage spectra. Owing to compensation effects the calculated neutron multiplication factors of beryllium are not very sensitive to the different beryllium data evaluations.