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US 8,525,411 B1Granted
Electrically heated planar cathode
AssigneeThermo Scientific Portable Analytical Instruments Inc.
InventorsMark T. Dinsmore, David J. Caruso
Life of this patent
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Abstract
An electrically heated planar cathode for use in miniature x-ray tubes may be spiral design laser cut from a thin tantalum alloy ribbon foil (with grain stabilizing features). Bare ribbon is mounted to an aluminum nitride substrate in a manner that is puts the ribbon in minimal tension before it is machined into the spiral pattern. The spiral pattern can be optimized for electrical, thermal, and emission characteristics.
Claims15
A planar cathode, comprising:
- a first substrate;
- and
- a laminate of a foil and a second substrate, the foil and the second substrate having matching thermal coefficients of expansion, the laminate being suspended over the first substrate,
- wherein the foil is shaped into a predetermined geometric pattern, the foil having performance parameters that are selected from a group including area, voltage, current, power, and electron emission;
- and
- wherein there is thermal isolation between the foil and the first substrate.
3 more elements
A method of making a planar cathode, comprising:
- brazing a foil to an AlN substrate to generate a laminate;
- shaping the foil in the laminate into a predetermined geometric pattern;
- and
- mounting the laminate on a header.
1 more element
Dependencies are inferred from the claim text.