Moxtek, Inc.

Varian Medical Systems, Inc.

Todd S Parker

Kasey Otho Greenland

Eric Miller

Rick Steck

Wayne Rollins Hansen

James E Burke

James Russell Boye

Steven D Liddiard

Colton Bridger Woodman

Dave Reynolds

Michael S Almond

Steven Liddiard

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 targetcan be mounted by an adhesion-layeron the x-ray window. The adhesion-layercan include chromium. A sealing-layercan seal the x-ray window to a flange. Material of the sealing-layercan be different from material of the adhesion-layer. There can be a gapbetween the flangeand the target. There can be a conductive-layeron the x-ray windowin the gap. A thickness Ts of the adhesion-layerbetween the sealing-layerand the x-ray windowcan be different than a thickness Tt of the adhesion-layerbetween the targetand the x-ray window

X-ray tube with improved spectrum

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.

Planar filament with focused, central electron emission

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-housingand a distal-housing, which can be connected to each other by an interface-ringfor 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-housingcan be greater than a maximum outer diameter Dd of the distal-housing, for improved blocking of x-rays. This diameter difference can allow improved x-ray shielding with less material.

X-ray source shielding

An x-ray tube can include an x-ray window sealed to a mount. An inner-collimator can be adjacent to, but not sealed to, the x-ray window. The inner-collimator can be sandwiched between the x-ray window and an insulating-layer. The insulating-layer can span an inner-collimator-aperture of the inner-collimator, forming an isolated cavity at the inner-collimator-aperture. Walls of the cavity can include the x-ray window, the inner-collimator, and the insulating-layer. The x-ray tube can have a light weight, can block x-rays in undesirable directions, and can shape the x-ray beam.

X-ray tube with inner-collimator

An x-ray tubecan have (a) an enclosure electrically-insulating a cathodefrom an anode; (b) a coating-ringon an inner-face of the enclosure, the coating-ringencircling a longitudinal-axisof the enclosure; and (c) an interruption-ringlocated at the inner-face of the enclosure at a different location than the coating-ring. The interruption-ringcan encircle the longitudinal-axisat a different location along the longitudinal-axiswith respect to the coating-ring. The interruption-ringcan encircle the longitudinal-axisat a different radius from the longitudinal-axisthan the coating-ring. The coating-ringand the interruption-ringcan reduce uneven electrical charge build-up on the inner-face of the enclosure, and can protect the triple-point.

Interruption-ring in an x-ray tube

Interruption-ring in an X-ray tube

X-ray transparent insulation can be sandwiched between an x-ray window and a ground plate. The x-ray transparent insulation can include aluminum nitride, boron nitride, or polyetherimide. The x-ray transparent insulation can include a curved side. The x-ray transparent insulation can be transparent to x-rays and resistant to x-ray damage, and can have high thermal conductivity. An x-ray window can have high thermal conductivity, high electrical conductivity, high melting point, low cost, and matched coefficient of thermal conductivity with the anode. The x-ray window can be made of tungsten. For consistent x-ray spot size and location, a focusing plate and a filament can be attached to a cathode with an open channel of the focusing plate aligned with a longitudinal dimension of the filament. Tabs of the focusing plate bordering the open channel can be bent to align with a location of the filament.

X-ray tube insulation, window, and focusing plate

An x-ray source can include an x-ray tube, and a heat sink for removal of heat from the x-ray tube. The heat sink can be thermally coupled to the anode and can extend away from the anode along a heat sink longitudinal axis. The heat sink can have a base and a fin extending from the base. The base can have a greater thickness nearer the anode, and a reduced thickness along the heat sink longitudinal axis to a smaller thickness farther from the anode.

X-ray tube heat sink and target material

An x-ray tube anode can include an electron hole extending from an electron entry at an exterior of the anode into a core of the anode, and an x-ray hole extending from an x-ray exit at the exterior of the anode into the core of the anode. The x-ray hole can intersect the electron hole at the core of the anode. In one embodiment, the electron hole and the x-ray hole can form a seamless bore from the electron entry to the x-ray exit. In another embodiment, the anode can be a single, integral, monolithic material with a single bore extending therethrough. In another embodiment, the core of the anode can include a target material located at a concave wall of the core of the anode.

X-ray tube single anode bore

An x-ray tube can provide x-ray spot stability, even for a small x-ray tube. The x-ray tube can have small target displacement, where target displacement is a displacement of the target material, towards the electron-emitter, along a longitudinal-axis of the anode, from x-ray powered-off state to stable operation, based on elongation of the anode. The x-ray tube can include a heatsink with an array of fins extending away from a base in opposite directions. A first fan can be attached to one end of the array of fins, oriented to face the base, and configured to direct an airstream towards the base. A second fan can be attached to opposite ends, oriented to face away from the base, and configured to draw the airstream from the base. Plate(s) can be located on sides of the fins to direct air flow from the first fan to the second fan.

X-ray spot stability

A x-ray tube comprising an anode sealed to a flexible coupling. The flexible coupling can allow the anode to deflect or tilt in various directions to allow an electron beam to impinge upon various selected regions of an anode target. A method of utilizing different regions of an x-ray tube target by tilting or deflecting an x-ray tube anode to cause an electron beam to impinge on a selected region of the target.

Tiltable or deflectable anode x-ray tube

A transmission x-ray tube comprising an end window hermetically sealed to a flexible coupling. The flexible coupling can allow the window to shift or tilt in one direction or another direction to allow an electron beam to impinge upon one region of the window or another region of the window. A method of utilizing different regions of an x-ray tube target by tilting an x-ray tube window at an acute angle with respect to an electron beam axis to cause an electron beam to impinge on a selected region of the window and tilting the window in a different direction to allow the electron beam to impinge on a different selected region of the window.

Multi-target X-ray tube with stationary electron beam position

An x-ray tube includes an evacuated envelope, and a cathode assembly and an anode assembly both disposed in the evacuated envelope. The cathode assembly includes a cathode shield, a supporting body disposed inside the cathode shield, and an electron source attached to the supporting body and partially enclosed by the cathode shield. The anode assembly includes a target configured to produce x-rays upon impingement by electrons produced by the electron source. The cathode shield comprises a shield base material and a layer over at least a portion of the base material. The layer comprises an emissivity enhancer having an emissivity greater than the emissivity of the shield base material. The layer may comprise an emissive coating applied on the portion of the base material. Alternatively, the layer may comprise a greened surface formed by a greening process.

X-ray tube cooling by emissive heat transfer

Cathode assembly for a long throw length x-ray tube. In one example embodiment, a cathode assembly for an x-ray tube includes an electron emitter, an acceleration region, and a drift region. The electron emitter includes a curved emitting surface configured to emit an electron beam having a y-dimension that is greater than an x-dimension at the electron emitter. The acceleration region is defined adjacent to the electron emitter. The acceleration region is configured such that when the electron beam propagates within the acceleration region, the electron beam accelerates in a z-direction substantially normal to a midpoint of the curved emitting surface. The drift region is defined between the acceleration region and an anode. The drift region is configured such that the combined lengths of the drift region and the acceleration region are sufficient for the y-dimension to be less than the x-dimension at the anode.

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Kaysville, UT, United States of America

Todd S Parker