Patent ID: 8254526
Filing Date: 2012-08-28
Classification: H01J

Abstract:
1. A thermionic electron emitter comprising: an inner part including a heatable flat emission surface; an outer part including a surrounding surface substantially enclosing the emission surface; a heating arrangement for heating the emission surface to a temperature for thermionic electron emission; wherein the outer part is mechanically connected to the inner part in a connection region apart from the emission surface; wherein the surrounding surface is thermally isolated from the emission surface in an isolation region apart from the connection region; wherein the surrounding surface is laterally spaced apart by a gap from the emission surface in the isolation region; wherein the heating arrangement comprises two emitter terminals arranged at the inner part at opposing position with respect to the emission surface such that an electrical heating current can be induced in the emission surface by applying a voltage to the emitter terminals; wherein the outer part is mechanically connected to the inner part in a connection region opposite to the emission surface with respect to an emitter terminal; wherein the inner part and the outer part are each formed from a different material being one of a metal, a metal alloy and a metal sandwich combination, wherein the inner part and the outer part are fixed to the same end region of the terminals.