| 摘要 |
In a hot cathode of an X-ray tube of the kind having a thermoelectronic emitter supported by a heating element, the emitter is comprised of plural emitter regions separated from each other. Each emitter region has the largest measure less than 3 mm, so that no crack occurs on the thermoelectronic emitter. The hot cathode is comprised of a heating element made of glassy carbon and a thermoelectronic emitter supported by the heating element. The emitter is comprised of plural emitter regions made of sintered lanthanum hexaboride. The hot cathode can be produced as described below. The heating element with a thickness of 1 mm is formed, at its thermoelectron-emitting side, with four recesses each of which is 2.6 mm in length, 0.5 mm in width and 0.3 mm in depth. The recesses are filled with lanthanum hexaboride powder, which is then sintered to complete four emitter regions.
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