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Rare Earth Chalcogenide Thermionic Emission Cathodes

IP.com Disclosure Number: IPCOM000075214D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Eastman, DE: AUTHOR [+3]

Abstract

The metallic trivalent rare earth chalcogenides RX where R is a rare earth and X is a chalcogen, satisfy the requisite conditions for thermionic emission cathodes. They are materials useful for high-current density and long-lifetime cathodes. Among these materials gadolinium sulphide 5GdS= or gadolinium selenide 5GdSe= are the most desirable.

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Rare Earth Chalcogenide Thermionic Emission Cathodes

The metallic trivalent rare earth chalcogenides RX where R is a rare earth and X is a chalcogen, satisfy the requisite conditions for thermionic emission cathodes. They are materials useful for high-current density and long-lifetime cathodes. Among these materials gadolinium sulphide 5GdS= or gadolinium selenide 5GdSe= are the most desirable.

Housing 4, is established on base plate 6 to form vacuum chamber 5 which is connected to a vacuum pump, not shown, via connection 8. The cathode configuration is formed by evaporating a film of rare earth chalcogenide 1, e.g. gadolinium sulphide SGdS= or gadolinium selenide (GdSe) onto front surface 2 of tantalum foil 3. Tantalum foil 3 has connector portions 7 and 9, which are bent- back sections of an original tantalum ribbon of which foil 3 is also a section. Cathode film 1 is heated by the tantalum foil 3 which is heated ohmically using the AC voltage supply 10 via wires 11 and 12. The thermionic electron emission from cathode film 1 is collected by the anode plate 13. The DC voltage 14 is applied between film 1 and anode 13, and the DC current to the anode plate 13 is measured by ammeter 15.

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