Measurements of neutron spectra produced from a thick lead target bombarded with 0.5- and 1.5-GeV protons

Neutron spectra produced from a thick lead target bombarded with 0.5 and 1.5 GeV protons have been measured in order to provide experimental data for benchmarking the medium-energy particle transport calculations. The accurate neutron spectra were obtained in the energy region between 1.6 and 150 MeV. The measured data have been compared with the calculated results of an NMTC/JAERI-MCNP-4A code system. The calculation reproduces the experiment fairly well for the lower energy less than 10 MeV. It, however, gives about 50% lower neutron flux in the energy region between 20 and 80 MeV. By using the in-medium nucleon–nucleon scattering cross sections, this disagreement has been reduced.