Development of a barium-free high-temperature cesium Tacitron

A barium-free, high-temperature, cesium Tacitron has been developed using a platinum, hollow cathode, emitter. The hollow cathode emitter used in our investigation is designed to enhance the current emission of a Tacitron cathode without the use of barium in the switch. In a barium-cesium Tacitron, the barium is known to cover the surface of a molybdenum emitter lowering its work function. The barium however limits the lifetime of the Tacitron, unless sophisticated seal technology is used in the manufacture of the Tacitron. The hollow cathode emitter was operated at current densities from 2.5 A/cm/sup 2/ up to 7.0 A/cm/sup 2/. Continuous operation of the Tacitron was demonstrated at 100-150 V and repetition rates of up to 5.8 kHz with measured voltage drops of 3.5-9.0 V. The results of the experimental characterization are compared to the computer model, and the applicability of this unique Tacitron design is discussed.