The neutron spectrum at the DUT (at 8 cm from the target) with 13MeV and 0.16mC proton beam has been calculated using MCNPX.
Without any moderate material, the most-fast neutron with energies above 0.1MeV has been produced: Intensities are approximately 1.5×1010 n/cm2 /sec. The thermal neutron with energies blow 1eV has been produced with 5cm thick polyethylene moderation: Intensities are approximately 0.5×1010 n/cm2 /sec. 1-MeV equivalent neutron fluence (øeq,1Mev,Si) and the neutron energy spectrum hardness parameter (Heq,1Mev,Si) for silicon have been calculated: the values are listed below. In order to adsorb the thermal neutron, cadmium cover has been used.