Independent production cross sections for Hg isotopes from the reaction of 600-MeV O-18 with Pb

Independent cross sections for all the Hg isotopes produced in the reaction of 600-MeV O-18 with a molten natural Pb target have been measured down to about 2 mub. The measurement is based on a radiochemical gamma-spectroscopy technique combined with rapid gas thermochromatography. The observed Hg-isotope distribution from Hg-180 to Hg-209 is compared with those previously reported from the reaction of 600-MeV p with a natural Pb target, and from two-proton-removal reactions measured by the inverse-kinematics method at relativistic energies. The comparisons make available some additional information for improving knowledge of spallation-reaction mechanisms in peripheral nuclear collisions. It is noted that the production cross sections for neutron-deficient heavy residues and the yield of fast neutrons emitted in proton-induced reactions should increase with increasing incident proton energy from 600 MeV to 1 GeV.