IONIC SPECIES PRESENT IN CESIUM DISCHARGES

Measurements have been made of the positive ion composition of cesium plasmas for normalized pressures from 10⁻⁴ to 10⁻¹ Torr using ion‐sampling techniques. At low pressure (≈ 10⁻⁴ Torr), Cs⁺ is dominant; however, at approximately 10⁻¹ Torr, the ion signals of Cs⁺ and ${\mathrm{Cs}}_2^{+}$ are comparable. The ion‐current ratio $\mathrm{I(}{\mathrm{Cs}}_3^{+}\mathrm{)/I(}{\mathrm{Cs}}^{+})$ increases rapidly with pressure.