Shielding Experiments under JASMIN Collaboration at Fermilab (IV) Measurement and Analyses of High-Energy Neutron Spectra in the Anti-Proton Target Station

Neutron spectra in high-energy region between 1 and 100 MeV in the shield configuration of the anti-proton target station and a 120-GeV proton beam at Fermi National Accelerator Laboratory (Fermilab) were determined using the reaction rate data obtained with the multi-foil activation method. Two kinds of methods were employed for the determination of neutron spectra: one is the fitting method which is newly developed in this work, another is the unfolding method with SAND-II code. The calculations were performed using the PHITS. From the comparison between the calculated and experimental neutron spectra, it concluded that the PHITS can be used for shielding design of highenergy proton accelerators.