A STUDY PROGRAM ON CESIUM VAPOR-FILLED THERMIONIC CONVERTERS HAVING HIGH VACUUM WORK FUNCTION EMITTER MATERIALS.
Annual summary rept., 1 Nov 62-31 Oct 63,
MARTIN CO BALTIMORE MD
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An extensive mapping of the performance of cesium vapor-filled thermionic energy conversion devices was obtained for the high vacuum work function emitter materials iridium and rhenium. Characteristic current versus voltage curves and summaries of the output power density are given for the emitter temperature range of 1600-2100 K, the liquid cesium temperature range of 450-675 K, the collector temperature range of 555-1075 K and for interelectrode spacing from 0.004 to 0.052 in. The devices used in this program were of flat-plate geometry and were so designed that the interelectrode spacing could be varied accurately and continuously under the conditions that the other test parameters were maintained constant. Consequently, the dependence of performance on interelectrode spacing could be measured to high precision. At low cesium pressure, the best performance is obtained at the widest interelectrode spacing. For the intermediate range of cesium pressures, the best performance is obtained at intermediate 0.012 - 0.032 in. values of the interelectrode gap. At the highest cesium pressures, the best performance is obtained at the closest spacings. Author