ELECTRON SPACE-CHARGE-LIMITED OPERATION OF CESIUM THERMIONIC CONVERTERS

Journal Article · Sun Apr 01 04:00:00 EST 1962 · Journal of Applied Physics (U.S.)

DOI:https://doi.org/10.1063/1.1728752· OSTI ID:4781582

Carabateas, E N

Experimental results from a cesium thermionic converter show that at low emitter temperatures and high cesium pressures, the output current approaches an asymptotic value as the emitter is made more and more negative with respect to the collector. With further decrease in voltage the curreni jumps to much higher values. The assumption was made that the operation of the converter under these conditions is electron space-chargelimited and that in the high current mode, collision ionization is present. A quantitative analysis of this electron space- charge-limited operation is presented, and an expression for the limiting value of the output current is obtained. A method is outlined by which the difference in emitter and collector work functions can be found from an experimental current- voItage characteristic and conversely such a characteristic can be plotted if sufficient information is given. This method is applied to experimental I-V curves obtained from a parallel plate converter with a tantalum emitter. From these curves the emitter work function and the true saturation current were estimated. These values of work function are approximately 0.5 v less than extrapolated values obtained from other experiments for cesium on tantalum. With the assumption that ions are introduced in the interelectrode spacing only by surface ionization, the magnitudes of the emitter and -collector sheaths are computed at different points of the I-V curve. (auth)

• Research Organization: Thermo-Electron Engineering Corp., Waltham, Mass.
• NSA Number: NSA-16-016842
• OSTI ID: 4781582
• Journal Information: Journal of Applied Physics (U.S.), Journal Name: Journal of Applied Physics (U.S.) Journal Issue: 4 Vol. Vol: 33; ISSN JAPIA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CESIUM
COATING
CONFIGURATION
CURRENTS
EFFICIENCY
ELECTRIC CHARGES
ELECTRIC POTENTIAL
ELECTRODES
ELECTRONICS
ELECTRONS
EMISSION
GENERATORS
IONIZATION
IONS
LOW TEMPERATURE
NESDPS Office of Nuclear Energy Space and Defense Power Systems
OPERATION
PHYSICS
PLATES
PRESSURE
SCATTERING
SPACE CHARGE
SURFACES
TANTALUM
THERMIONICS
THERMODYNAMICS
WORK FUNCTIONS