Intermediates in the Nucleon-Transfer Process in Reactions of Nitrogen-14 with Cesium-133

Abstract

The average ranges and excitation functions for ${}_{}{}^{132}{}_{}{}^{}\mathrm{Cs}$ and ${}_{}{}^{130}{}_{}{}^{}\mathrm{Cs}$ through ${}_{}{}^{127}{}_{}{}^{}\mathrm{Cs}$ from the reaction ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$+${}_{}{}^{133}{}_{}{}^{}\mathrm{Cs}$ have been measured. Angular distributions and differential ranges have also been determined for the products ${}_{}{}^{132}{}_{}{}^{}\mathrm{Cs}$, ${}_{}{}^{130}{}_{}{}^{}\mathrm{Cs}$, ${}_{}{}^{129}{}_{}{}^{}\mathrm{Cs}$, and ${}_{}{}^{127}{}_{}{}^{}\mathrm{Cs}$. Both the average ranges and angular distributions for ${}_{}{}^{130}{}_{}{}^{}\mathrm{Cs}$ through ${}_{}{}^{127}{}_{}{}^{}\mathrm{Cs}$ have been found to be the same: At 140-MeV incident energy the angular distributions peak at 34° in the laboratory (full width at half-maximum, 19°) and the recoil energies are 2 MeV. The ${}_{}{}^{132}{}_{}{}^{}\mathrm{Cs}$ angular distribution and average range correspond to a collision in which a Rutherford trajectory, appropriate to a grazing collision, is followed. The total cross section for ${}_{}{}^{130}{}_{}{}^{}\mathrm{Cs}$ through ${}_{}{}^{127}{}_{}{}^{}\mathrm{Cs}$, at 140 MeV, was found to be 250±35 mb, whereas the cross section for ${}_{}{}^{132}{}_{}{}^{}\mathrm{Cs}$ is 160 mb. At this energy, upper limits of 0.2±0.2 mb and 30±10 mb have been set respectively for the production of ${}_{}{}^{131}{}_{}{}^{}\mathrm{Cs}$ and ${}_{}{}^{126}{}_{}{}^{}\mathrm{Cs}$. A mechanism of nucleon transfer in a peripheral collision followed by deexcitation via nucleon emission from the excited intermediate is considered. Based on this model, angular distributions, average ranges, and excitation functions have been calculated and found in good agreement with experimental results.