Provided is an X-ray tube capable of obtaining a clear X-ray image by reducing unnecessary X-rays radiated from a holder shaft. The X-ray tube includes an electron source 12 for generating an electron beam B, an anode 13 for accelerating the electron beam B and having a hole 13a allowing the electron beam B to pass through, a cylindrical holder shaft 14 forming a passage for allowing the electron beam B to pass through a hole 13a of the anode 13, a magnetic lens 17 arranged around the holder shaft 14 and configured to converge the electron beam B, a target holder 15 connected to the holder shaft 14, a target 16 arranged in the target holder 15 so that the electron beam B collides with the target 16, and an irradiation window 15b arranged in the target holder 15 and configured to extract X-rays generated from the target 15 to the outside. The inner wall of the holder shaft 14 is made of a carbon material to reduce X-rays generated when the electron beam B hits the holder shaft 14.

Provided is an X-ray tube capable of obtaining a clear X-ray image by reducing unnecessary X-rays radiated from a holder shaft. The X-ray tube includes an electron source 12 for generating an electron beam B, an anode 13 for accelerating the electron beam B and having a hole 13a allowing the electron beam B to pass through, a cylindrical holder shaft 14 forming a passage for allowing the electron beam B to pass through a hole 13a of the anode 13, a magnetic lens 17 arranged around the holder shaft 14 and configured to converge the electron beam B, a target holder 15 connected to the holder shaft 14, a target 16 arranged in the target holder 15 so that the electron beam B collides with the target 16, and an irradiation window 15b arranged in the target holder 15 and configured to extract X-rays generated from the target 15 to the outside. The inner wall of the holder shaft 14 is made of a carbon material to reduce X-rays generated when the electron beam B hits the holder shaft 14.

An embodiment of an X-ray tube is described that comprises an outer cylinder; a window positioned on an end of the outer cylinder; an electron gun comprising an emission orifice, wherein the electron gun is coupled to a side of the outer cylinder at an angle that orients the emission orifice toward the window; and a rod centrally positioned within the outer cylinder, wherein the rod comprises a concave geometry at a distal end proximal to the electron gun and a target surface configured at an angle that orients the target surface towards the emission orifice, wherein the concave geometry is configured to position the target surface to have a focal spot size of an electron beam from the emission orifice in range of about 2-6 m.

An embodiment of an X-ray tube is described that comprises an outer cylinder; a window positioned on an end of the outer cylinder; an electron gun comprising an emission orifice, wherein the electron gun is coupled to a side of the outer cylinder at an angle that orients the emission orifice toward the window; and a rod centrally positioned within the outer cylinder, wherein the rod comprises a concave geometry at a distal end proximal to the electron gun and a target surface configured at an angle that orients the target surface towards the emission orifice, wherein the concave geometry is configured to position the target surface to have a focal spot size of an electron beam from the emission orifice in range of about 2-6 m.

An x-ray window can include a thin film that comprises boron. The thin film can be relatively thin, such as for example 200 nm. This x-ray window can be strong; can have high x-ray transmissivity; can be impervious to gas, visible light, and infrared light; can be easy of manufacture; can be made of materials with low atomic numbers, or combinations thereof. The thin film can include an aluminum layer. A support structure can provide additional support to the thin film. The support structure can include a support frame encircling an aperture and support ribs extending across the aperture with gaps between the support ribs. The support structure can also include boron ribs aligned with the support ribs.

An x-ray window can include a thin film that comprises boron. The thin film can be relatively thin, such as for example 200 nm. This x-ray window can be strong; can have high x-ray transmissivity; can be impervious to gas, visible light, and infrared light; can be easy of manufacture; can be made of materials with low atomic numbers, or combinations thereof. The thin film can include an aluminum layer. A support structure can provide additional support to the thin film. The support structure can include a support frame encircling an aperture and support ribs extending across the aperture with gaps between the support ribs. The support structure can also include boron ribs aligned with the support ribs.

In one embodiment, an x-ray tube 15 can be used closer to a sample. An angle A.sub.1 between an anode axis 02 and an electron-beam axis 01 can be 10 and 80 and an angle A.sub.2 between the anode axis 02 and an x-ray axis 03 can be 10 and 80. In another embodiment, a cap 20 on an anode 12 can block x-rays emitted in undesired directions. The cap 20 can include an internal cavity 24, an electron-beam hole 21, an anode hole 22, and an x-ray hole 23. In another embodiment, an electrical connection between an x-ray tube 15 and a power supply 18 can be reliable and easy to manufacture. The anode 12 can include a hole 31 at an end of the anode 12 sized and shaped for insertion of an electrical connector 32.

In one embodiment, an x-ray tube 15 can be used closer to a sample. An angle A.sub.1 between an anode axis 02 and an electron-beam axis 01 can be 10 and 80 and an angle A.sub.2 between the anode axis 02 and an x-ray axis 03 can be 10 and 80. In another embodiment, a cap 20 on an anode 12 can block x-rays emitted in undesired directions. The cap 20 can include an internal cavity 24, an electron-beam hole 21, an anode hole 22, and an x-ray hole 23. In another embodiment, an electrical connection between an x-ray tube 15 and a power supply 18 can be reliable and easy to manufacture. The anode 12 can include a hole 31 at an end of the anode 12 sized and shaped for insertion of an electrical connector 32.

An X-ray tube includes: a vacuum housing configured to include an internal space which is vacuum; a target unit configured to be disposed in the internal space, and include a target that generates an X-ray by using an electron beam incident therein, and a target support unit that supports the target, the X-ray generated by the target being transmitted through the target support unit; and an X-ray emission window configured to be so provided as to face the target support unit, and seal an opening of the vacuum housing, the X-rays transmitted through the target support unit being transmitted through the X-ray emission window. At least a part of the X-ray emission window is in contact with the target support unit.

An X-ray tube includes: a vacuum housing configured to include an internal space which is vacuum; a target unit configured to be disposed in the internal space, and include a target that generates an X-ray by using an electron beam incident therein, and a target support unit that supports the target, the X-ray generated by the target being transmitted through the target support unit; and an X-ray emission window configured to be so provided as to face the target support unit, and seal an opening of the vacuum housing, the X-rays transmitted through the target support unit being transmitted through the X-ray emission window. At least a part of the X-ray emission window is in contact with the target support unit.