Abstract: A flat emitter is disclosed. In an embodiment, the flat emitter includes an emitter surface, which upon application of a heating voltage, emits electrons; a first end area, which has a first support rod; and a second end area, which has a second support rod. At least one first support rod has a narrow section extending in a longitudinal direction and is bonded to the first end area or a second support rod, which has a narrow section extending in a longitudinal direction and is bonded to the second end area. A flat emitter of this kind is structurally simple and offers a high level of electron emission at the same time as a longer useful life.

Abstract: A cathode HAS a cathode head in which a surface emitter is arranged that emits electrons upon application of a heating voltage. The surface emitter is fashioned as a parallel surface emitter with at least two emitter surfaces spaced apart from one another, to which at least one electrically conductive cutoff electrode is fed that is galvanically separated from the parallel surface emitter. Such a cathode has a good cutoff capability.

Abstract: In a thermionic surface emitter and an associated method to operate an x-ray tube, the surface emitter has a conductor path in its emission surface, the conductor path having at least one current entrance point and at least one current exit point. In the thermionic surface emitter, the width of the conductor path is variable i.e. is non-constant or non-uniform. The electrical resistance of the emitter structure thus varies along the heating current path, with the consequence that a symmetrical emission structure can be achieved at a working point established by the hardware geometry.

Abstract: A cathode HAS a cathode head in which a surface emitter is arranged that emits electrons upon application of a heating voltage. The surface emitter is fashioned as a parallel surface emitter with at least two emitter surfaces spaced apart from one another, to which at least one electrically conductive cutoff electrode is fed that is galvanically separated from the parallel surface emitter. Such a cathode has a good cutoff capability.