Rotating anode X-ray tube

A rotating anode X-ray tube including an envelope and, mounted within the envelope:

• an anode mounted for rotation, an electron gun arranged to direct an electron beam to be incident on the surface of said anode to generate X-rays therefrom and a generally cylindrical shroud member arranged closely to enclose said electron beam at the anode surface to shield other parts of the anode surface from secondary electrons emitted at the region of incidence of the electron beam, said shroud including a window of X-ray transmissive material.

A rotating anode X-ray tube including an envelope and, mounted therein:

• an anode mounted for rotation about an axis thereof;
• an electron gun arranged to direct a beam of electrons to be incident on the surface of said anode at a region which moves over said surface in the course of said rotation;
• a cover, fixed relative to said electron gun, arranged to be closely adjacent to a substantial part of the surface of said anode on which the beam is incident and including an aperture by which the electron beam may reach said surface.

A rotating anode x-ray tube including an anode adapted for rotation about an axis therethrough, an electron gun arranged to direct a beam of electrons to be incident on the surface of the anode at a region which moves thereover in the course of said rotation, a shroud member adapted to collect backscattered electrons produced at said anode by said incident beam and means by which x-rays, generated at said anode by said incident beam, may leave said tube.

An X-ray tube having an anode, an electron gun arranged to direct a beam of electrons to be incident on the surface of the anode at a region from which X-rays are generated, a shroud member closely surrounding said anode, at least immediately adjacent said region, a collimating aperture in said shroud at which the X-rays are allowed to exit and are constrained to a fan-shaped distribution, the sides of the aperture in the plane of the fan being curved to reduce the proportion of said X-ray emitting region viewed with increasing angle from the centre to the edge of the fan distribution.

An X-ray tube having an envelope and, mounted in the envelope:

• an anode, an electron gun arranged to direct a beam of electrons to be incident on the surface of the anode at a region from which X-rays are generated, a shroud member closely surrounding said anode, at least immediately adjacent said region, a collimating aperture in said shroud at which the X-rays are allowed to exit and are constrained to a fan-shaped distribution, the sides of the aperture in the plane of the fan being shaped so as to reduce the intensity of the X-rays transmitted by the aperture with increasing angle from the centre line of the fan distribution.