Measurement of neutron spectra and fluxes at the IPNS Radiation Effects Facility

We have measured the neutron spectra, fluxes, and flux distributions produced by nuclear spallation resulting from 478-MeV proton bombardment of tantalum and depleted uranium targets surrounded by a thick lead neutron reflector. The configuration was chosen to simulate a radiation effects facility at a spallation-neutron source. The method of multiple foil activation with spectrum unfolding by the STAYSL computer code was used to measure the neutron spectra. The experimental results are compared in detail with the results of computer calculations on the same configuration of targets and reflector. The neutron production and transport codes HETC and VIM were employed in these calculations. Based on these measurements, the Radiation Effects Facility (REF) was designed and constructed at the IPNS. Using similar activation techniques the neutron spectra, fluxes and flux distributions have been determined for the REF