Yields of Stable and Radioactive Rare-Gas Isotopes Formed by 3- and 29-GeV Proton Bombardment of Cu, Ag, Au, and U

The yields of all rare-gas products, including stable species, with half-lives >10 h, produced in 3- and 29-GeV proton bombardment of Cu, Ag, Au, and U were measured. Mass-spectrometric measurements of ${\mathrm{Ne}}^{20}$, ${\mathrm{Ne}}^{21}$, ${\mathrm{Ar}}^{38}$, ${\mathrm{Kr}}^{83}$, and ${\mathrm{Xe}}^{131}$ represent total chain yields for these mass numbers. Spallation processes can account for Ne yields from Cu; Ar and Kr from Ag; and Xe from Au. Fission and spallation mechanisms satisfactorily describe the Kr from Au and the Kr and Xe from U. Ne and Ar yields from Au and U do not seem to be formed by spallation and fission processes, but appear to result from the same processes which lead to high yields of even lighter fragments previously observed in high-energy reactions.