Charge Transfer between Positive Cesium Ions and Cesium Atoms

The cross section for charge transfer between cesium ions and cesium atoms has been determined as a function of primary ion energy from 50 to 4000 eV. At each energy the cross section was obtained from measurements of the number of slow ions formed along a known length of the fast primary ion beam in passing through cesium vapor, the primary beam current, and the number density of cesium atoms inside the interaction region. The measured cross sections are higher than those of other investigations within the same energy range in which different methods were used, but are consistent with those of an investigation in the energy range 5 to 25 keV. The result of a least-mean-squares fit indicates that the cross section may be represented between 50 eV and 4000 eV by the expression $Q^{\frac{1}{2}}\times {10}^8=26.8-1.46\mathrm{}\ln V$, where $Q$ is the cross section (${\mathrm{cm}}^2$) and $V$ is the primary ion beam energy (eV).