Spectra of Fast Neutrons from Water Pulsed with 14-MeV Neutrons

The validity of the neutron Monte Carlo transport code, SORS, has been established for the transport of fast neutrons through water by comparing the measured time spectra of neutrons from spherical water targets of 1.0 and 1.8 mean-free-paths radii with the calculations. The energy degradation and spatial spreading of a beam of 14-MeV neutrons through a thickness of water comparable to the thickness of a human body were calculated for use in the design of experiments to treat cancer tumors with 14-MeV neutron beams. For use in shielding applications, further calculations have also been made of the transport of neutrons from an isotropic source of 14-MeV neutrons located at the center of spherical water shields having radii from 0.5 to 7.0 mfp.