  A calorimetric-time-of-flight (CTOF) technique was used for real-time,
high-precision measurement of neutron spectrum at an angle of 175 degrees from
the initial proton beam direction, which hits a face plane of a cylindrical
lead target of 20 cm in diameter and 25 cm thick. A comparison was performed
between the neutron spectra predicted by the MARS, RTS&T, MCNP6, and the MCNPX
2.6.0 transport codes and that measured for 200, 400, 600, 800, and 1000 MeV
protons
