Application of microfabrication technology to thermionic energy conversion. Progress report No. 1, 1 May-31 October, 1979

Technical Report · Tue Jan 01 04:00:00 EST 1980

DOI:https://doi.org/10.2172/5712333· OSTI ID:5712333

Brodie, I.; Gates, D. C.

In a theoretical and experimental program to evaluate those areas where three-dimensional microfabrication techniques could be important for improving methods of thermionic energy conversion, effort in the first reporting period has been directed toward a theoretical study of microstructures of electrodes for thermionic energy converters. The properties of a cesiated tungsten thermionic energy converter were analyzed with electrode temperatures compatible with a flame-generated heat source (T/sub c/ = 1650/sup 0/K and T/sub a/ = 700/sup 0/K), in order to estimate the efficiency, power production, and appropriate electrode spacing for microfabricated devices. The analysis yielded a maximum efficiency of 16 percent and corresponding electrical power of 11 W/cm/sup 2/, requiring an emission current of 18 A/cm/sup 2/. The study revealed that to attain these parameters, electrode spacing must be approximately 1 ..mu..m, and that such a close-spaced diode with cesiated tungsten electrodes would operate approximately as a vacuum diode. That is, the principal function of the cesium would be to control the work function of the electrode surfaces. Operating at the point of peak efficiency, little space-charge limitation of the emission and little plasma resistance would be produced, because the atom/atom and electron/atom mean free paths would be larger than the interelectrode space.

• Research Organization: SRI International, Menlo Park, CA (USA)
• DOE Contract Number: AC02-79ET15423
• OSTI ID: 5712333
• Report Number(s): DOE/ET/15423-1
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300401* -- Thermionic Converters-- Design & Development
ALKALI METALS
CESIUM
CRYSTAL STRUCTURE
DIODE TUBES
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRODES
ELECTRON TUBES
ELEMENTS
FABRICATION
FLAMES
HEAT SOURCES
METALS
MICROSTRUCTURE
MINIATURIZATION
NESDPS Office of Nuclear Energy Space and Defense Power Systems
REFRACTORY METALS
SIZE
THERMIONIC COLLECTORS
THERMIONIC CONVERTERS
THERMIONIC DIODES
THERMIONIC EMITTERS
THERMIONIC TUBES
TRANSITION ELEMENTS
TUNGSTEN