Claims
- 1. An x-ray source, comprising an x-ray tube that produces a selected x-ray frequency band of a plurality of selectable x-ray frequency bands and that does not include any moving part.
- 2. An x-ray tube comprising:
a vacuum chamber vessel; a source of an electron beam inside the vacuum chamber vessel; a target disposed inside the vacuum chamber vessel, the target comprising
a substrate, and a plurality of selectable deposits attached to the substrate, wherein each different deposit of the plurality of selectable deposits includes an atomic element having a different atomic number; and a source of an electric field for directing the electron beam to a selected deposit of the plurality of selectable deposits.
- 3. The x-ray tube of claim 2, wherein:
the substrate is disposed to form one portion of the vacuum chamber vessel; the substrate has strength to withstand a vacuum in the vacuum chamber vessel; and the substrate is transparent to x-rays produced in the plurality of selectable deposits.
- 4. The x-ray tube of claim 2, wherein the substrate has a thermal conductivity in excess of ten Watts per meter per Kelvin.
- 5. The x-ray tube of claim 2, wherein the substrate has a thermal conductivity in excess of one hundred Watts per meter per Kelvin.
- 6. The x-ray tube of claim 2, wherein the substrate is composed of at least one of polycrystalline diamond, sapphire, and silicon.
- 7. The x-ray tube of claim 3, wherein the substrate is spray cooled by a cooling system external to the x-ray tube.
- 8. The x-ray tube of claim 3, wherein the x-ray tube and the cooling system form a compact integrated unit that weighs less than about twenty pounds.
- 9. The x-ray tube of claim 2, wherein there is no moving mechanical part inside the x-ray tube to produce any of a plurality of x-ray frequencies.
- 10. The x-ray tube of claim 2, wherein there is no movable x-ray filter to block a portion of an x-ray spectrum generated at the target.
- 11. The x-ray tube of claim 2, wherein a K-shell fluorescence energy of the atomic element in the selectable deposit is less than about 50 thousand electron volts.
- 12. The x-ray tube of claim 2, wherein the plurality of deposits include:
a first deposit that includes a first element having an atomic number between about 64 and about 74; and a second deposit that includes a second element having an atomic number between about 87 and about 92.
- 13. The x-ray tube of claim 2, wherein the source of the electron beam is controlled to produce an electron beam with electron energy matched to a K-shell fluorescence energy of the atomic element in the selectable deposit.
- 14. The x-ray tube of claim 2, wherein the substrate is the same as one deposit of the plurality of deposits.
- 15. An x-ray tube comprising:
a vacuum chamber vessel; a source of an electron beam inside the vacuum chamber vessel; a target disposed inside the vacuum chamber vessel, the target comprising
a substrate, and a plurality of selectable deposits attached to the substrate; and a means for directing the electron beam to a selected deposit of the plurality of deposits, wherein
each different deposit of the plurality of deposits includes an atomic element that has a different a K-shell fluorescence energy, and a first deposit of the plurality of deposits includes a first element that has a K-shell fluorescence energy less than about 50 thousand electron volts.
- 16. The x-ray tube of claim 15, wherein a second deposit includes a second element that has a K-shell fluorescence energy greater than about 100 thousand electron volts.
- 17. The x-ray tube of claim 15, wherein the first element has an atomic number between about 64 and about 74.
- 18. The x-ray tube of claim 17, wherein the first element is Holmium.
- 20. The x-ray tube of claim 16, wherein the second element has an atomic number between about 87 and about 92.
- 20. The x-ray tube of claim 20, wherein the second element is Thorium.
- 21. The x-ray tube of claim 15, wherein:
the substrate is disposed to form one portion of the vacuum chamber vessel; the substrate has strength to withstand a vacuum in the vacuum chamber vessel; and the substrate is transparent to x-rays produced in the plurality of selectable deposits.
- 22. The x-ray tube of claim 15, wherein the substrate has a thermal conductivity in excess of ten Watts per meter per Kelvin.
- 23. The x-ray tube of claim 15, wherein the substrate has a thermal conductivity in excess of one hundred Watts per meter per Kelvin.
- 24. The x-ray tube of claim 15, wherein the substrate is composed of at least one of polycrystalline diamond, sapphire, and silicon.
- 25. The x-ray tube of claim 21, wherein the substrate is spray cooled by a cooling system external to the x-ray tube.
- 26. The x-ray tube of claim 25, wherein the x-ray tube and the cooling system form a compact integrated unit that weighs less than about twenty pounds.
- 27. The x-ray tube of claim 15, wherein there is no moving mechanical part inside the x-ray tube to produce any of a plurality of x-ray frequencies.
- 28. The x-ray tube of claim 15, wherein there is no movable x-ray filter to block a portion of an x-ray spectrum generated at the target.
- 29. The x-ray tube of claim 15, wherein the means for directing the electron beam is a source of an electric field.
- 30. The x-ray tube of claim 15, wherein the source of the electron beam is controlled to produce an electron beam with electron energy matched to a K-shell fluorescence energy of the atomic element in the selectable deposit.
- 31. The x-ray tube of claim 15, wherein the source of the electric field and the source of the electron beam are computer controlled.
- 32. The x-ray tube of claim 18, wherein the source of the electron beam is controlled to produce an electron beam with electron energy of about 45 thousand electron volts when the electron beam is directed to the first deposit.
- 33. The x-ray tube of claim 20, wherein the source of the electron beam is controlled to produce an electron beam with electron energy of about 110 thousand electron volts when the electron beam is directed to the second deposit.
- 34. An x-ray tube comprising:
a vacuum chamber vessel; a source of an electron beam inside the vacuum chamber vessel; and a target disposed inside the vacuum chamber vessel, the target comprising
a substrate, and a deposit different from the substrate attached to the substrate, wherein
the electron beam is directed to the deposit to produce x-rays, and the substrate has a thermal conductivity many times greater than a thermal conductivity of the deposit.
- 35. The x-ray tube of claim 34, wherein the thermal conductivity of the substrate is greater than 200 Watts per meter per Kelvin.
- 36. The x-ray tube of claim 34, wherein the substrate is polycrystalline diamond.
- 36. The x-ray tube of claim 34, wherein the substrate is sapphire.
- 38. The x-ray tube of claim 34, wherein:
the substrate is disposed to form one portion of the vacuum chamber vessel; the substrate has strength to withstand a vacuum in the vacuum chamber vessel; and the substrate is transparent to x-rays produced in the deposit.
- 39. The x-ray tube of claim 34, wherein the substrate is spray cooled by a cooling system external to the x-ray tube.
- 40. The x-ray tube of claim 34, wherein the x-ray tube and the cooling system form a compact integrated unit that weighs less than about twenty pounds.
- 41. The x-ray tube of claim 34, wherein there is no movable x-ray filter to block a portion of an x-ray spectrum generated at the target.
- 42. The x-ray tube of claim 34, wherein the source of the electron beam is controlled to produce an electron beam with electron energy matched to a K-shell fluorescence energy of the atomic element in the deposit.
- 43. The x-ray tube of claim 42, wherein a K-shell fluorescence energy of the atomic element in the deposit is less than about 50 thousand electron volts.
- 44. The x-ray tube of claim 34, wherein the target is substantially perpendicular to the electron beam.
- 45. The x-ray tube of claim 34, wherein the target is substantially oblique to the electron beam to spread heating of the deposit by the electron beam.
- 46. The x-ray tube of claim 45, wherein the target is substantially oblique to a ray emanating from the target to a subject external to an x-ray source that includes the x-ray tube.
- 47. An x-ray source comprising:
an x-ray tube; and a cooling system comprising:
a fluid vessel for containing a heat-exchange fluid outside the x-ray tube; the fluid vessel including a spray nozzle that directs the heat-exchange fluid to an outside face of a target of the x-ray tube for absorbing heat generated within the target; and a pump for forcing the heat-exchange fluid through the spray nozzle.
- 48. The x-ray source of claim 47, wherein the fluid vessel further includes a heat exchanger portion of the fluid vessel for directing heat from the heat-exchange fluid inside the fluid vessel to an ambient fluid outside the fluid vessel
- 49. The x-ray source of claim 48, wherein the x-ray tube and the cooling system form a compact integrated unit that weighs less than about twenty pounds.
- 50. The x-ray source of claim 47, wherein:
the x-ray tube further comprises a vacuum chamber vessel and the target includes a substrate disposed to form one portion of the vacuum chamber vessel; the substrate has strength to withstand a vacuum in the vacuum chamber vessel; and the spray nozzle directs the heat-exchange fluid to an outside face of the substrate.
- 51. The x-ray source of claim 47, wherein:
the target includes a deposit on the substrate; the substrate is transparent to x-rays produced in the deposit when the deposit is struck with an electron beam; and the substrate has a thermal conductivity that is greater than a thermal conductivity of the deposit.
- 52. The x-ray source of claim 47, wherein the pump is computer controlled for forcing the heat-exchange fluid through the spray nozzle at a variable rate sufficient for cooling the x-ray tube.
- 53. The x-ray source of claim 49, wherein fins rotated by the pump are disposed outside a fin tube.
- 54. The x-ray source of claim 53, wherein an electric motor for the pump and the fin tube rotated by the pump are coaxial.
- 55. The x-ray source of claim 53, wherein a power cable for the x-ray tube is passed inside the fin tube.
- 56. The x-ray source of claim 47, wherein the heat exchange fluid directed to the outside face of the target is in a liquid phase.
- 57. The x-ray source of claim 56, wherein at least some of the heat-exchange fluid converts to a vapor phase after absorbing the heat generated within the target.
- 58. A method of producing a selected x-ray frequency of a plurality of selectable x-ray frequencies, the method comprising the steps of:
controlling an electron beam source in an x-ray tube to produce an electron beam with electron energy corresponding to the selected x-ray frequency; and controlling an electric field source to produce an electric field to direct the electron beam onto a selected deposit and away from a different deposit of a plurality of deposits on a target substrate in the x-ray tube, wherein
each deposit of the plurality of deposits includes an atomic element with a K-shell fluorescence energy that corresponds to one frequency band of a plurality of selectable x-ray frequency bands, and the selected deposit includes an atomic element with a K-shell fluorescence energy that corresponds to the selected x-ray frequency band.
- 59. The method of claim 58, further comprising controlling a pump in a cooling system to provide a variable fluid flow rate sufficient to cool the x-ray tube.
- 60. A computer-readable medium carrying one or more sequences of instructions for producing a selected x-ray frequency of a plurality of selectable x-ray frequencies, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:
controlling an electron beam source in an x-ray tube to produce an electron beam with electron energy corresponding to the selected x-ray frequency; and controlling an electric field source to produce an electric field to direct the electron beam onto a selected deposit and away from a different deposit of a plurality of deposits on a target substrate in the x-ray tube, wherein
each deposit of the plurality of deposits includes an atomic element with a K-shell fluorescence energy that corresponds to one frequency band of a plurality of selectable x-ray frequency bands, and the selected deposit includes an atomic element with a K-shell fluorescence energy that corresponds to the selected x-ray frequency band.
- 61. An x-ray source comprising:
an x-ray tube comprising:
a vacuum chamber vessel; a source of an electron beam inside the vacuum chamber vessel; a target comprising
a substrate disposed to form one portion of the vacuum chamber vessel, wherein the substrate has strength to withstand a vacuum in the vacuum chamber vessel and is transparent to x-rays produced by the x-ray tube, and a plurality of deposits attached to the substrate, wherein each different deposit of the plurality of deposits includes an atomic element having a different atomic number; and a source of an electric field for directing the electron beam to a selctable deposit of the plurality of deposits; and a cooling system comprising:
a fluid vessel for containing a heat-exchange fluid outside the x-ray tube; the fluid vessel including:
a spray nozzle directing a liquid phase of the heat-exchange fluid to an outside face of the substrate for absorbing heat generated at the target; and a heat exchanger portion of the fluid vessel for directing heat from the heat-exchange fluid inside the fluid vessel to an ambient fluid outside the fluid vessel; and a computer controlled pump for forcing the liquid phase of the heat-exchange fluid through the spray nozzle at a variable rate sufficient for cooling the x-ray tube, wherein:
the plurality of deposits include a first deposit that includes a first element having an atomic number between about 66 and about 76 and a second deposit that includes a second element having an atomic number between about 89 and about 94; the substrate is composed of at least one of polycrystalline diamond, silicon, and sapphire; there is no moving mechanical part inside the x-ray tube; there is no movable x-ray filter to block a portion of an x-ray spectrum generated at the target; and the x-ray tube and the cooling system form a compact integrated unit that weighs less than about twenty pounds.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of Provisional Appln. 60/353,742 filed Jan. 31, 2002, the entire contents of which is hereby incorporated by reference as if fully set forth herein, under 35 U.S.C. §119(e).
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/US03/02590 |
1/30/2003 |
WO |
|