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Lanthanum Hexaboride Resistance Heated Apex Cathode

IP.com Disclosure Number: IPCOM000074983D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Blair, W: AUTHOR [+2]

Abstract

Figs. 1, 2 and 3 illustrate top and side views of a cathode for an electron beam apparatus. The cathode is an internal resistance heated lanthanum hexaboride filament, having a sharp symmetrical tip at its narrowest cross-section such that the emitting area is in the hottest region of the cathode. The cathode is designed so that the tip is produced at the point of narrowest cross-section in one single machining operation.

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Lanthanum Hexaboride Resistance Heated Apex Cathode

Figs. 1, 2 and 3 illustrate top and side views of a cathode for an electron beam apparatus. The cathode is an internal resistance heated lanthanum hexaboride filament, having a sharp symmetrical tip at its narrowest cross- section such that the emitting area is in the hottest region of the cathode. The cathode is designed so that the tip is produced at the point of narrowest cross- section in one single machining operation.

The cathode is mounted in the electron beam apparatus with a ceramic spacer located between its legs, and the cathode and spacer are secured in a ceramic holder by two screws.

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