X-ray tube with inner-collimator
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.
1. An x-ray tube comprising:
a cathode and an anode electrically insulated from one another;
the cathode configured to emit electrons, through an internal vacuum of the x-ray tube, towards the anode;
the anode configured to emit x-rays out of the x-ray tube, through an x-ray window, in response to impinging electrons from the cathode;
the anode includes an electrically conductive mount and an electrically conductive inner-collimator;
the mount faces the vacuum on one side and the inner-collimator at an opposite side;
the mount includes a mount-aperture;
the x-ray window spans the mount-aperture and is sealed to the mount;
the inner-collimator includes an inner-collimator-aperture aligned with the x-ray window and the mount-aperture to direct and collimate the x-rays;
the inner-collimator includes a proximal-end nearest the x-ray window and a distal-end farthest from the x-ray window;
an electrically insulative insulating-layer located at the distal-end of the inner-collimator and spanning the inner-collimator-aperture, forming an isolated cavity at the inner-collimator-aperture; and
walls of the cavity include the x-ray window, the inner-collimator, and the insulating-layer.
2. The x-ray tube of claim 1 , wherein the inner-collimator-aperture is free of electrical fields during operation of the x-ray tube.
3. The x-ray tube of claim 1 , wherein 15°≤A1≤70°, where A1 is an angle between a wall of the inner-collimator and an axis of the x-ray tube between a target material at the anode and an electron emitter at the cathode.
4. The x-ray tube of claim 1 , further comprising an electrically conductive proximal-conducting-layer on a face of the insulating-layer, spanning the inner-collimator-aperture, located between the inner-collimator and the insulating-laver, and located between the insulating-layer and the cavity.
5. The x-ray tube of claim 4 , further comprising:
an electrically conductive anode-ring encircling the mount;
the proximal-conducting-layer adjoining the anode-ring; and
the proximal-conducting-layer having an outer edge that terminates on a face of the anode-ring.
6. The x-ray tube of claim 1 , wherein:
the mount-aperture includes a wider-region and a narrower-region with a flange extending between the wider-region and the narrower-region;
the x-ray window is sealed to the mount on the flange;
the inner-collimator includes a ring that extends into the wider-region of the mount-aperture; and
the inner-collimator has a maximum diameter that is larger than a diameter of the wider-region of the mount-aperture.
7. The x-ray tube of claim 1 , further comprising:
the insulating-layer has a pair of opposite faces connected by an edge;
an electrically conductive proximal-conducting-layer is located on one of the pair of opposite faces;
an electrically conductive distal-conducting-layer is located on another of the pair of opposite faces; and
the proximal-conducting-layer spans the inner-collimator-aperture of the inner-collimator, is located between and adjoins the insulating-layer and the cavity, and is located between and adjoins the inner-collimator and the insulating-layer.
8. The x-ray tube of claim 7 , further comprising:
an outer-collimator adjoining the distal-conducting-layer, the distal-conducting-layer sandwiched between the outer-collimator and the insulating-layer; and
the outer-collimator having an outer-collimator-aperture aligned with the inner-collimator-aperture.
9. The x-ray tube of claim 1 , further comprising an absence of a hermetic seal between the inner-collimator and the x-ray window.
10. The x-ray tube of claim 1 , wherein:
the cavity is enclosed by the x-ray window, the inner-collimator, and the insulating-layer; and
the cavity is isolated from vacuum by the x-ray window and ambient air by the the inner-collimator and the insulating-layer.
11. An x-ray tube comprising:
a cathode and an anode electrically insulated from one another;
the cathode configured to emit electrons towards the anode;
the anode configured to emit x-rays out of the x-ray tube, through an x-ray window, in response to impinging electrons from the cathode;
an inner-collimator adjacent to the x-ray window, the inner-collimator having an inner-collimator-aperture aligned with the x-ray window configured to direct and collimate the x-rays, the inner-collimator having a proximal-end nearest the x-ray window and a distal-end farthest from the x-ray window;
an electrically insulative insulating-layer located at the distal-end of the inner-collimator and spanning the inner-collimator-aperture; and
an electrically conductive proximal-conducting-layer on a face of the insulating-layer, spanning the inner-collimator-aperture, and located between the inner-collimator and the insulating-lager.
12. The x-ray tube of claim 11 , wherein 15°≤A1≤70°, where A1 is an angle between a wall of the inner-collimator and an axis of the x-ray tube between a target material at the anode and an electron emitter at the cathode.
13. The x-ray tube of claim 11 , further comprising an electrically conductive distal-conducting-layer located on an opposite face from the proximal-conducting-layer.
14. The x-ray tube of claim 13 , further comprising:
an outer-collimator adjoining the distal-conducting-layer;
the distal-conducting-layer sandwiched between the outer-collimator and the insulating-layer; and
the outer-collimator having an outer-collimator-aperture aligned with the inner-collimator-aperture.
15. The x-ray tube of claim 14 , wherein a shape of the outer-collimator matches an extension of a shape of the inner-collimator.
16. An x-ray tube comprising:
a cathode and an anode electrically insulated from one another;
the cathode configured to emit electrons towards the anode;
the anode configured to emit x-rays out of the x-ray tube, through an x-ray window, in response to impinging electrons from the cathode;
an inner-collimator adjacent to the x-ray window, the inner-collimator having an inner-collimator-aperture, aligned with the x-ray window, configured to direct and collimate the x-rays, the inner-collimator having a proximal-end nearest the x-ray window and a distal-end farthest from the x-ray window;
an electrically insulative insulating-layer located at the distal-end of the inner-collimator and spanning the inner-collimator-aperture; and
15°≤A1≤70°, where A1 is an angle between a wall of the inner-collimator and an axis of the x-ray tube between a target material at the anode and an electron emitter at the cathode.
17. The x-ray tube of claim 16 , further comprising:
the insulating-layer having a pair of opposite faces connected by an edge;
an electrically conductive proximal-conducting-layer located on one of the pair of opposite faces;
an electrically conductive distal-conducting-layer located on another of the pair of opposite faces;
the proximal-conducting-layer spans the inner-collimator-aperture and is located between and adjoins the inner-collimator and the insulating-layer.
18. The x-ray tube of claim 17 , further comprising:
an outer-collimator adjoining the distal-conducting-layer;
the distal-conducting-layer sandwiched between the outer-collimator and the insulating-layer; and
the outer-collimator having an outer-collimator-aperture aligned with the inner-collimator-aperture.
19. The x-ray tube of claim 18 , wherein a shape of the outer-collimator matches an extension of a shape of the inner-collimator.
20. The x-ray tube of claim 16 , wherein the inner-collimator has at least 50 weight percent tungsten.