EXPERIMENTAL STUDIES OF Cs-CsF-Mo AND Cs-CsF-W PLASMA DIODE EMITTERS
Measurements are presented which demonstrate that the electron emission of molybdenum in cesium vapor is greatly enhanced by the addition of cesium fluoride. The enhancement amounts to a factor of about 340 at the maxima of the respective Langmuir S-curves for a cesium pressure of 10/sup -2/ mm Hg. The minimum effective work function of the Cs--CsF--Mo surface is 1.38 plus or minus 0.05 ev. Preliminary measurements of the work function of cesium fluoride coated tungsten were made by obtaining retarding potential curves for photo electrons liberated from the cesium fluoride coated tube wall by an external light source. An activation process is indicated by the fact that it is necessary to heat the tungsten wire to about 1100 deg K in order to obtain a high work function surface. A Cs--CsF --W emitter was incorporated irto a plasma cell of unguarded parallel plate design. At the initial emitter-collector spacing of 0.25 in. attempts to operate the cell in the low voltage arc regime met with little success, although some cross over into the useful power section of the current-voltage characteristic occurs for a cesium pressure of 0.1 mm Hg and emitter temperatures in the region about 1900 deg K. Arc currents extrapolated to zero voltage indicate that the emission of the Cs--CsF--W emitter is about the same as that from a Cs--CsF--Mo emitter. (auth)
- Research Organization:
- Los Alamos Scientific Lab., N. Mex.
- DOE Contract Number:
- W-7405-ENG-36
- NSA Number:
- NSA-16-030926
- OSTI ID:
- 4767115
- Report Number(s):
- LADC-5230
- Country of Publication:
- United States
- Language:
- English
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