Excitation Functions and Recoil Ranges of Residual Nuclei Produced through Kr-Induced Transfer Reactions inBi209Targets

The excitation functions and projected recoil ranges for ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$, ${}_{}{}^{210}{}_{}{}^{}\mathrm{Rn}$, and ${}_{}{}^{211}{}_{}{}^{}\mathrm{Rn}$ produced through ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ + ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ reactions have been measured from 430 to 500 MeV. Substantial values have been found for the cross sections at high energies. The general features of the reactions (the shapes of the excitation functions and the variation of recoil range versus incident energy) are very similar to results found with lighter projectiles and are unambiguously characteristic of non-compound-nucleus processes. Complementary measurements performed on a natural T1 target show that the cross sections for four-charge- and five-charge-transfer reactions are of the order of 1 mb. Therefore, in the reactions ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ + ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ → ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$, ${}_{}{}^{210-211}{}_{}{}^{}\mathrm{Rn}$, the contribution of the four- and five-charge transfers followed by fast $\alpha$ decay is not significant, and the main mechanisms involved are the transfers of two and three charges.