X-ray tube

An X-ray tube comprising:

• a cathode having an electron emission source that emits electrons;
• an anode having an anode target facing the cathode in a direction along an X-ray tube axis, and in which a focal spot is formed where electrons emitted from the electron emission source collide to emit X-rays;
• a cathode hood enclosing an orbit of electrons from the electron emission source to the focal spot and the anode target, and on which a first opening through which X-rays pass is formed;
• a first X-ray transmission window blocking at least a part of the first opening and having an X-ray transmittance higher than an X-ray transmittance of the cathode hood;
• an envelope housing the cathode, the anode target, the cathode hood, and the first X-ray transmission window;
• and
• a first restraining member and a second restraining member,
• wherein
• the first X-ray transmission window has a first area facing the first opening, a frame-like second area enclosing the first area, and a first side surface overlapping an outer edge of the second area,
• the cathode hood has an inner circumferential surface enclosing the orbit of electrons and the anode target, an outer circumferential surface opposite the inner circumferential surface, a first hole opening on the outer circumferential surface and recessed toward the inner circumferential surface to house the first X-ray transmission window, a first bottom surface in the first hole, an inner wall surface in the first hole, and a concave surface opening on the inner wall surface,
• the first opening is open on the inner circumferential surface and the first bottom surface, respectively,
• the first bottom surface has a frame-like overlap space facing the second area of the first X-ray transmission window,
• the first side surface of the first X-ray transmission window faces the inner wall surface,
• the first restraining member faces the second area of the first X-ray transmission window, sandwiches the second area of the first X-ray transmission window together with the overlap space, and has a framed shape and a second side surface facing the inner wall surface,
• the second restraining member is located in a space enclosed by the concave surface and the second side surface, is formed of a metal softer than a material forming the cathode hood, and has a contact surface that is pressed against the second side surface, and
• the first X-ray transmission window is maintained in a state of being restrained to the overlap space by the first restraining member and the second restraining member.

An X-ray tube comprising:

• a cathode having an electron emission source that emits electrons;
• an anode having an anode target facing the cathode in a direction along an X-ray tube axis, and in which a focal spot is formed where electrons emitted from the electron emission source collide to emit X-rays;
• a cathode hood enclosing an orbit of electrons from the electron emission source to the focal spot and the anode target, and on which a first opening through which X-rays pass is formed;
• a first X-ray transmission window blocking at least a part of the first opening and having an X-ray transmittance higher than an X-ray transmittance of the cathode hood;
• an envelope housing the cathode, the anode target, the cathode hood, and the first X-ray transmission window;
• and
• a first restraining member,
• wherein
• the first X-ray transmission window has a first area facing the first opening, a frame-like second area enclosing the first area, and a first side surface overlapping an outer edge of the second area,
• the cathode hood has an inner circumferential surface enclosing the orbit of electrons and the anode target, an outer circumferential surface opposite the inner circumferential surface, a first hole opening on the outer circumferential surface and recessed toward the inner circumferential surface to house the first X-ray transmission window, a first bottom surface in the first hole, an inner wall surface in the first hole, a second hole continuous from the first hole, opening on the outer circumferential surface, and recessed toward the inner circumferential surface, and a second bottom surface in the second hole,
• the first opening is open on the inner circumferential surface and on the first bottom surface, respectively,
• the first bottom surface has a frame-like overlap space facing the second area of the first X-ray transmission window,
• the first side surface of the first X-ray transmission window faces the inner wall surface,
• the first restraining member faces the second area of the first X-ray transmission window, sandwiches the second area of the first X-ray transmission window together with the overlap space, and has a framed shape and a second side surface facing the inner wall surface,
• the first restraining member and the second bottom surface are welded together, and
• the first X-ray transmission window is maintained in a state of being restrained to the overlap space by the first restraining member fixed to the cathode hood.