Measurement of neutron production spectra at the forward direction from thick graphite, aluminum, iron and lead targets bombarded by 250 MeV protons

Iwamoto, Yosuke   ; Taniguchi, Shingo*; Nakao, Noriaki*; Itoga, Toshio*; Nakamura, Takashi*; Nakane, Yoshihiro  ; Nakashima, Hiroshi; Satoh, Daiki   ; Yashima, Hiroshi*; Yamakawa, Hiroshi*; Oishi, Koji*; Tamii, Atsushi*; Hatanaka, Kichiji*

Neutron energy spectra produced at the forward direction from thick graphite, aluminum, iron and lead targets bombarded by 250 MeV protons were measured by the TOF method at RCNP of Osaka University. The experimental data were compared with the calculated results of the PHITS, MCNPX codes. All calculations give lower neutron energy spectra than the experimental ones for all targets above 20 MeV and must be improved for neutron production at 0-degree. These experimental data will be useful as benchmark data for investigating the accuracy of the Monte Carlo simulation and for the shielding design of accelerator facilities.