Oxide cathode for an electron gun, having a denser and thinner emissive zone
AssigneeThomson Licensing S. A.
InventorsJean-Luc Ricaud, Gerard Proudhon
Life of this patent
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Abstract
Cathode comprising a substrate (2) supporting a cathode emissive coating, comprising what is called an emissive central zone (12) and what is called a nonemissive peripheral zone (11); according to the invention: the average density and the emissive zone (12) is greater than that in said nonemissive zone (11), the average thickness in the emissive zone (12) is less than that in the nonemissive zone (11). In this way it is possible to significantly limit the drift in cut-off voltage, while still maintaining good maximum emission performance in DC mode and in pulse mode.
Claims15
An oxide cathode for an electron gun, comprising a substrate supporting a porous cathode emissive coating based on one or more alkaline-earth oxides, comprising what is called an emissive central zone and what is called a nonemissive peripheral zone, wherein:
- the average density of this coating in said emissive zone is greater than that of this same coating in said nonemissive zone;
- the average thickness of said coating in the emissive zone is less than that of this same coating in the nonemissive zone.
Dependencies are inferred from the claim text.