Measurement of thick target neutron yields at 0° bombarded with 140, 250 and 350 MeV protons

Neutron energy spectra at 0° produced from stopping-length graphite, aluminum, iron and lead targets bombarded with 140, 250 and 350 MeV protons were measured at the neutron TOF course in RCNP of Osaka University. The neutron energy spectra were obtained by using the time-of-flight technique in the energy range from 10 MeV to incident proton energy. To compare the experimental results, Monte Carlo calculations with the PHITS and MCNPX codes were performed using the JENDL-HE and the LA150 evaluated nuclear data files, the ISOBAR model implemented in PHITS, and the LAHET code in MCNPX. It was found that these calculated results at 0° generally agreed with the experimental results in the energy range above 20 MeV except for graphite at 250 and 350 MeV.