X-RAY TUBE Russian patent published in 2008 - IPC H01J35/02 

FIELD: sources of X-ray radiation.

SUBSTANCE: X-ray tube of permanent radiation, consists of cylindrical anode, annular cathode, which consists of several glow threads, focusing electrode, windows for withdrawal of X-ray radiation and leak-tight casing. Annular cathode, which consists of two and more glow threads, is isolated from tube casing and focusing electrode, which allows to change size of focal spot by means of control voltage supply on cathode in regard to casing and focusing electrode. Anode is made in the form of massive copper cylinder, to the end of which target is fixed by means of soldering or welding, made of material that is necessary for generation of corresponding X-ray radiation. Focusing electrode is installed so that products of cathode evaporation would not get to anode end surface. Internal part of tube casing is additional element of focusing, configuration of internal surface of tube casing that faces cathode and focusing electrode is designed to provide focusing of electrons on anode surface. Output collimator is added in tube design, and its dimensions are selected so that cathode evaporation products would not get on the surface of output window.

EFFECT: simplification of design, reduction of dimensions, increase of tube operation resource, possibility of focal spot regulation by means of cathode potential change in regard to focusing electrode.

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