Measurements of delayed neutrons yields and time spectra from 1 GeV protons interacting with thick ^natPb, ²⁰⁹Bi and ^natFe targets

Abstract

Abstract. This paper presents the experimental results on the DN yields and time spectra from 1 GeV protons interacting with the nat Pb, 209 Bi and nat Fe targets of variable thicknesses from 5 cm to 55 cm. Both absolute yields and time constants were obtained. In parallel, the MCNPX and PHITS codes were used to predict the DN precursors and construct the theoretical DN tables. Different model parameters are examined and show significant dependence on the choice of the intra-nuclear cascade and fission-evaporation models used. These data and modelling are of great importance for the new generation spallation neutron sources based on liquid metal technologies. Finally, the above experiment allowed the determination of the production cross sections of a number of DN precursors as, 87 Br, 88 Br and 17 N. These results permit the examination of two different reaction mechanisms, namely fission and fragmentation, implemented in high energy transport codes.