CTOF measurements and Monte Carlo analyses of neutron spectra for the backward direction from an iron target irradiated with 400-1200Â MeV protons

A calorimetric-time-of-flight (CTOF) technique was used for real-time, high-precision measurement of the neutron spectrum at an angle of 175° from the initial proton beam direction, which hits a face plane of a cylindrical iron target of 20 cm in diameter and 25 cm thick. A comparison was performed between the neutron spectra predicted by the MARS and the MCNPX codes and that measured for 400, 600, 800, 1000 and 1200 MeV protons.