The neutron spectrum inside the moderator cavity has been characterized using foil activation techniques. Measured neutron intensities are compared to MCNPX calculations.
Copper, gold, and zinc foils were used to measure the thermal flux, i.e. neutrons with energies up to 1eV. Iron foils and sulfur pellets were used to measure the fast neutron flux with energies above 0.1 MeV. The fission monitor also provides real time relative dosimetry.
Fast, > ~ 0.1 MeV,
Thermal, < 1 eV,
S, Fe and Cu,Au, Zn foil activations have been measured at 8cm from the Be target with 13MeV and 0.16mC proton beam. Measured intensities are ~10-20% lower then calculations.