Reproducibility of thermionic performance

The performance of 12 identical thermionic converters fabricated to a given set of specifications, is reported. The converters were of planar geometry. The emitters were solid rhenium, and the collectors were arc-cast molybdenum. The average output power of the converters at an emitter temperature of 2000°K and an output voltage of 0.7 volt was 37.5 watts (18.75 W/cm
²
) with a standard deviation of 1.3 watts (0.65 W/cm
²
). Voltage-current characteristics of the converters at an emitter temperature of 1975°K are also presented.