Neutron activation by neutrons produced via proton-induced spallation in a liquid-mercury target. Measurements and assessment of uncertainties

A preliminary test of a liquid mercury target for the production of neutrons by spallation was undertaken at the Alternating Gradient Synchrotron facility at Brookhaven National Laboratory. Neutron activation of elemental foils placed on the target demonstrates that a range of neutron energies does exist, as expected, and that the neutron flux is at a maximum 10-20 cm from the front of the target, moving deeper with increasing proton energy. Uncertainties in the activity calculations are in general significantly <10%. Impurities in some of the foils are a significant source of interference for some reactions, although there is no interference for most of the reactions. The presence of many interference-free reactions, along with the low uncertainties indicates that the foils will be useful benchmarks to validate the neutronics codes utilized in the target design. (author)