According to one embodiment, an X-ray tube includes an anode target, a cathode including a filament and a convergence electrode which includes a groove portion, and an envelope. The groove portion includes a pair of first bottom surfaces which are located in the same plane as the filament and between which the filament is interposed in a width direction of the groove portion, and a pair of second bottom surfaces between which the filament and the pair of first bottom surfaces are interposed in a length direction of the groove portion and which are located closer to an opening of the groove portion than the pair of first bottom surfaces.

Some embodiments include an apparatus, comprising: a vacuum enclosure including an opening; a support structure disposed in the vacuum enclosure, the support structure comprising: a first portion attached to the vacuum enclosure at the opening; and a second portion extending within the vacuum enclosure; and a plurality of getters disposed on the second portion of the support structure.

Some embodiments include an apparatus, comprising: a vacuum enclosure including an opening; a support structure disposed in the vacuum enclosure, the support structure comprising: a first portion attached to the vacuum enclosure at the opening; and a second portion extending within the vacuum enclosure; and a plurality of getters disposed on the second portion of the support structure.