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EXPERIMENTAL OPTIMIZATION OF CESIUM VAPOR THERMIONIC CONVERTERS WITH METAL EMITTERS

Journal Article · · Advan. Energy Conversion
OSTI ID:4716061

Parametric studies are being conducted utilizing both cylindrical fixed- spacing and parallel-plane, variablespacing thermionic converters. A brief description of the design and fabrication of these converters is given, and the techniques of component preparation, the use of getters and the philosophy of operation are illustrated. The instrumentation for control and measurement of the various parameters is discussed. The emitters of these parallel plane and cylindrical diodes are heated by electron bombardment. Constant power input is achieved by using a controller which is insensitive to back heating from the emitter. The load which is used with these diodes can be varied to produce the full operating range from reverse currents to the applied voltage region. At the higher emitter temperatures, surface ionization appears to be sufficient for space charge neutralization. Under these conditions the power density of a converter, operated at constant emitter temperature and optimum cesium pressure, increases as the spacing is decreased. At lower emitter temperatures, approximately 1450 un. Concent 85% C and less for molybdenum, surface ionization is insufficient to neutralize the space charge. Thus, the additional ions must be supplied from volume ionization, resulting in an optimum spacing for maximum power densities. Curves showing power densities, optimum cesium pressures, and optimum collector temperatures versus spacing for the variable spacing diode are given and discussed. Efficiency curves for several refractory emitters are given. The effects of the individual optimization of cesium pressure, collector temperature, and load resistance are shown for both ignited'' and unignited'' modes of operation. (auth)

Research Organization:
Atomics International, Canoga Park, Calif.
NSA Number:
NSA-17-020604
OSTI ID:
4716061
Journal Information:
Advan. Energy Conversion, Journal Name: Advan. Energy Conversion Vol. Vol: 2
Country of Publication:
Country unknown/Code not available
Language:
English