Electron beam window structure for broad area electron beam generators

Claim 1

In an electron acceleration device for delivering to a region outside of the device an electron beam of substantial cross-section comprising a housing having an aperture, electron emission means within said housing and spaced from said aperture, an electron window adapted to be disposed within said aperture and defining with said housing an essentially gas-tight emission chamber, said electron window providing an exit from said housing through which said electron beam is transmitted when said housing is evacuated, said electron emission means actuated and an acceleration potential defining an electric acceleration field provided for accelerating electrons toward said electron window, the improvement which comprises: a flat electrically conductive metal electron window support adapted to be sealably mounted in said housing aperture, said support having a high thermal conductance, a first surface for sealably receiving said electron window and a second surface facing said electron emission means; said support having a plurality of elongated slots of a length and number to define the cross-section of said beam, said slots each being spaced apart a distance to define thin thermally conducting metal cross members each having an exposed end portion in contact with and supporting said window; thermally and electrically conductive metal portions defining the bottom of each slot and comprising in part said second surface, each said metal portion having a plurality of closely spaced holes extending along the length of said slots and providing communication between the interior of said housing and said slots, said holes being of a size and spaced one from another to prevent the electric acceleration field from extending into said slots a substantial portion of the depth of said slots; and conduit means positioned in relation to said cross members through which fluid coolant can be passed in heat-exchange relationship with said cross members.