A flat emitter for uses within an x-ray tube is formed of an electron emissive material that includes one or more stress compensation features capable of reducing the total stress in the flat emitter due to thermal expansion and/or centrifugal acceleration force. The one or more stress compensation features of the flat emitter for reducing the total stress in the flat emitter are formed directly on the flat emitter, are formed on the support structure for the flat emitter and connected to the flat emitter, or a combination thereof.

A monolithic graphite heater for heating a thermionic electron cathode includes first and second electrically conductive arms, each one of the first and second electrically conductive arms having an electrode mount at a proximal end, a thermal apex at a distal end, and a transitional region between the electrode mount and the thermal apex; a cathode mount electrically and mechanically coupling each thermal apex to form a maximum Joule-heating region at or adjacent the cathode mount and decreasing Joule heating along each transitional region; and a press-fit aperture formed in the cathode mount, the press-fit aperture sized to receive at least a portion of the thermionic electron cathode for facilitating thermionic emission produced therefrom in response to operative heat power generation provided by the maximum Joule-heating region.

A cathode device includes an emitter tip for generating electrons. An elongate heater is included having proximal and distal ends. The emitter tip can be located at the distal end of the heater. Two spaced apart legs can extend away from the distal end of the heater, terminating at the proximal end and forming an elongate slot therebetween. Two electrical contacts can compressively engage respective opposite outer surfaces of the two legs at the proximal end of the heater to mechanically secure and electrically connect the two legs of the heater to respective electrical contacts at a junction that is at a location spaced away from the emitter tip to keep the junction cooler.

An emitter includes an insulator, a pair of terminals attached to the insulator separately from each other, at least one filament attached between the pair of terminals in an arch shape, and an electron source fixed to the filament. The filament has bent portions between a contact with respect to the electron source and contacts with respect to the terminals. A device is provided with the emitter.

A flat emitter for uses within an x-ray tube is formed of an electron emissive material that includes one or more stress compensation features capable of reducing the total stress in the flat emitter due to thermal expansion and/or centrifugal acceleration force. The features of the emitter for reducing the total stress in the flat emitter are formed directly on the emitter, are formed on the support structure for the emitter and connected to the emitter, or a combination thereof.

An emitter includes an insulator, a pair of terminals attached to the insulator separately from each other, at least one filament attached between the pair of terminals in an arch shape, and an electron source fixed to the filament. The filament has bent portions between a contact with respect to the electron source and contacts with respect to the terminals. A device is provided with the emitter.