Moxtek, Inc.

A filament assembly 10 for an x-ray tube 20 can include a planar filament 11 electrically-coupled between and substantially-encircled by a pair of collector plates C 1 and C 2 . The pair of collector plates C 1 and C 2 can support the planar filament 11 so that it does not twist or warp and align the filament assembly 10 within a cathode cup 33 . The pair of collector plates C 1 and C 2 can block electrons emitted from a back side of the filament. Without the collector plates C 1 and C 2 , back side electrons can change direction by about 180°, hit the target, and distort a target electron spot. Each collector plate C 1 or C 2 can include holes H 1 and H 2 . These holes H 1 and H 2 can aid in alignment of the collector plates C 1 and C 2 with electrodes 31 and electrode 32 , can allow welding at a lower temperature, and can facilitate weld inspection.

A collimator for an x-ray tube can be a monolithic, integral structure. The collimator can include a proximal-end closest to a cathode and a distal-end farthest from the cathode. The proximal-end can adjoin a vacuum inside of the x-ray tube. The distal-end can adjoin the air. The collimator can include an aperture extending therethrough. An x-ray window can be mounted across the aperture. The aperture can include a collimation-region between the x-ray window and the distal-end, and a drift-region between the x-ray window and the proximal-end. X-rays can be generated inside of the collimator.

A planar filament for an x-ray tube can have a different cross-sectional area at different locations. In regions of smaller cross-sectional area, there can be higher current density, and thus increased heating and higher temperature of the wire. In regions of larger cross-sectional area, there can be lower current density, and thus decreased heating of the wire. Regions of larger cross-sectional area can also be stronger, thus reducing early filament failures. Wider regions can have increased area for electron emission. By adjusting the cross-sectional area and width of the wire at different locations, electron emission can be largely confined to a center of the filament, and filament life can increase.

X-rays can be used for material identification. X-ray beam purity, target adhesion the x-ray window, and a robust hermetic seal of the x-ray window are useful. To achieve these objectives, a target 17 can be mounted by an adhesion-layer 16 on the x-ray window. The adhesion-layer 16 can include chromium. A sealing-layer 13 can seal the x-ray window to a flange 19 . Material of the sealing-layer 13 can be different from material of the adhesion-layer 16 . There can be a gap 21 between the flange 19 and the target 17 . There can be a conductive-layer 18 on the x-ray window 14 in the gap 21 . A thickness Ts of the adhesion-layer 16 between the sealing-layer 13 and the x-ray window 14 can be different than a thickness Tt of the adhesion-layer 16 between the target 17 and the x-ray window 14.

A planar filament for an x-ray tube can have a different cross-sectional area at different locations. In regions of smaller cross-sectional area, there can be higher current density, and thus increased heating and higher temperature of the wire. In regions of larger cross-sectional area, there can be lower current density, and thus decreased heating of the wire. Regions of larger cross-sectional area can also be stronger, thus reducing early filament failures. Wider regions can have increased area for electron emission. By adjusting the cross-sectional area and width of the wire at different locations, electron emission can be largely confined to a center of the filament, and filament life can increase.

As an x-ray tube expands and contracts during heating and cooling, its hermetic seal can be damaged. A more robust hermetic seal, particularly as the x-ray tube is heated and cooled, is desirable. The x-ray tube described herein can include a proximal-housing 13 and a distal-housing 14 , which can be connected to each other by an interface-ring 15 for improved hermetic seal. Added x-ray tube weight, of material used for blocking x-rays, can make it difficult to transport the x-ray tube. Reducing this weight is desirable. A maximum outer diameter Dp of the proximal-housing 13 can be greater than a maximum outer diameter Dd of the distal-housing 14 , for improved blocking of x-rays. This diameter difference can allow improved x-ray shielding with less material.

A filament assembly 10 for an x-ray tube 20 can include a planar filament 11 electrically-coupled between and substantially-encircled by a pair of collector plates C 1 and C 2 . The pair of collector plates C 1 and C 2 can support the planar filament 11 so that it does not twist or warp and align the filament assembly 10 within a cathode cup 33 . The pair of collector plates C 1 and C 2 can block electrons emitted from a back side of the filament. Without the collector plates C 1 and C 2 , back side electrons can change direction by about 180°, hit the target, and distort a target electron spot. Each collector plate C 1 or C 2 can include holes H 1 and H 2 . These holes H 1 and H 2 can aid in alignment of the collector plates C 1 and C 2 with electrodes 31 and electrode 32 , can allow welding at a lower temperature, and can facilitate weld inspection.

An x-ray tube can have a stable electron beam with resulting stable x-ray beam, reduced arcing failure of the x-ray tube, and reduced shielding mass. The x-ray tube can include a cathode and an anode electrically insulated from each other by a first enclosure and a second enclosure. A blocking disc can be located at or near a junction of the first enclosure and the second enclosure. A field-shaping cup can extend into a hollow region of the second enclosure. A low-Z-layer can be located on a side of the blocking disc that faces the electron emitter.

In an x-ray source, an isolation circuit can isolate bias voltage at a cathode from a bias voltage at an alternating current source (AC source). The isolation circuit can transfer alternating current from the AC source to the cathode. The isolation circuit can be made repeatedly with minimal variation or failed parts, can be light, and can be small. The isolation circuit can include planar transformer(s). Each planar transformer can include a primary trace on a primary circuit board and a secondary trace on a secondary circuit board. The primary trace and the secondary trace can each include a spiral shape. The primary trace can be located in close proximity to the secondary trace such that alternating electrical current through the primary trace will induce alternating electrical current through the secondary trace.

A collimator for an x-ray tube can be a monolithic, integral structure. The collimator can include a proximal-end closest to a cathode and a distal-end farthest from the cathode. The proximal-end can adjoin a vacuum inside of the x-ray tube. The distal-end can adjoin the air. The collimator can include an aperture extending therethrough. An x-ray window can be mounted across the aperture. The aperture can include a collimation-region between the x-ray window and the distal-end, and a drift-region between the x-ray window and the proximal-end. X-rays can be generated inside of the collimator.