Production of Neon-24 and Sodium-24 in the 1-3-GeV Proton Bombardment of Copper, Silver, Gold, and Uranium Targets

Ratios of the cumulative yields of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Ne}$ to the independent yields of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ have been measured from Cu, Ag, Au, and U targets irradiated with 1-, 2-, and 3-GeV protons. The ratios are essentially energy-independent for each target, although the cross-section values themselves increase by factors up to 10 between 1 and 3 GeV. The ratios increase with the $\frac{N}{Z}$ ratio of the target from 0.04 for Cu to 0.4 for U at 2 and 3 GeV. These results combined with previously published data show that from all targets the maxima of the isobaric yield distribution for the mass-24 chain lie on or slightly to the neutron-rich side of the stability line. The peak of the isobaric distribution shifts slowly towards higher neutron/proton ratios as the mass of the target increases.