Benchmarking of evaluated nuclear data for bismuth by spherical shell transmission experiments with central T(d,n) and Cf-252 neutron sources

The results of neutron transmission experiments on a spherical bismuth shel l of 9.0 cm wall thickness with T(d,n) and Cf-252 point neutron sources at its center are reported. The neutron leakage spectra were measured by the t ime-of-flight method from 14 MeV down to 100 keV. Descriptions of the exper imental arrangement, time-of-flight spectrometer, measurements and data red uction procedures are given. The measured data are compared with results of three-dimensional Monte-Carlo calculations with the MCNP code, using the E NDF/B-VI, EFF-2.4 and JENDL-FF nuclear data libraries. For all three librar ies, the calculated neutron leakage deviates significantly from the measure d one in case of the T(d,n) source, whereas for the Cf-252 source good agre ement is found. (C) 1999 Elsevier Science S.A. All rights reserved.