Interesting characteristics of rubidium vapor discharges

The basic properties of alkali vapor discharges are reviewed and exemplified for the case of rubidium vapor. The low arc drop exhibited by these discharges is their primary interesting feature. Arc drops as low as two volts with current densities up to one ampere per sq. cm. have been achieved. Behavior of pure alkali vapor discharges are highly temperature dependent. Experiments are described showing how the temperature dependence of the arc drop is substantially rduced by using an alkali vapor noble gas (Xenon) combination. The possibility of interruption of alkali vapor discharges by grid action is discussed in the light of the known theories pertaining to grid control of arc currents. On-off control of the arc current of a d-c rubidium vapor discharge has been achieved in an experimental thyratron. Interruption has been achieved in an experimental thyratron. Interruption of arcs of fairly high currents (250 milliamps/cm²and above) by a negative voltage as low as fifteen volts applied to the grid has been observed. The tube in which this behavior was observed is presented and experimental results are discussed.