초록 ▼

A radiation source is disclosed comprising a source of charged particles that travel along a path. Target material lies along the path to generate radiation upon impact by the beam. A magnet is provided to deflect the beam prior to impacting the target. The magnet may generate a time-varying magneti

A radiation source is disclosed comprising a source of charged particles that travel along a path. Target material lies along the path to generate radiation upon impact by the beam. A magnet is provided to deflect the beam prior to impacting the target. The magnet may generate a time-varying magnetic field or a constant magnetic field. A constant magnetic field may be varied spatially across the beam. The magnet may be an electromagnet or a permanent magnet. In one example, deflection of the beam results in impact of the beam on the target along a plurality of axes. In another example, portions of the beam are differentially deflected. The source may thereby irradiate an object to be scanned with more uniform radiation. The charged particles may be electrons or protons and the radiation may be X-ray or gamma ray radiation, or neutrons. Scanning systems incorporating such sources, methods of generating radiation and methods of examining objects are disclosed, as well.

대표청구항 ▼

1. A radiation source comprising:a housing; a first, accelerating chamber within the housing, to accelerate a beam of charged particles, the first chamber having an output; a second chamber within the housing, the second chamber having an input aligned with the output of the first chamber to receive

1. A radiation source comprising:a housing; a first, accelerating chamber within the housing, to accelerate a beam of charged particles, the first chamber having an output; a second chamber within the housing, the second chamber having an input aligned with the output of the first chamber to receive the beam of accelerated charged particles; a point target supported within the second chamber, wherein impact of the target by the accelerated charged particles causes generation of radiation; and a magnet supported by the housing proximate the second chamber, to provide a magnetic field to deflect at least a portion of the beam of accelerated charged particles prior to impacting the target, the magnet configured to cause a change in an angle of impact of the at least a portion of the beam on the target. 2. The radiation source of claim 1, wherein the magnet provides a time-varying magnetic field during operation.3. The radiation source of claim 2, wherein the magnet is an electromagnet.4. The radiation source of claim 3, wherein the electromagnet comprises:a core defining first and second opposing pole faces, wherein the core comprises material in which a magnetic field may be induced; a coil around at least a portion of the core; a current source coupled to the coil; and a controller coupled to the current source. 5. The radiation source of claim 4, wherein the core comprises a magnetic material.6. The radiation source of claim 4, wherein the controller selectively causes current flow in at least a first direction to provide a magnetic field to deflect the beam along a first axis.7. The radiation source of claim 6, wherein the controller selectively causes current flow in a second direction opposite the first direction, to generate a second magnetic field to deflect the beam along a second axis.8. The radiation source of claim 7, wherein the controller selectively causes no current flow, to allow the beam to travel undeflected, along a third axis.9. The radiation source of claim 8, wherein the controller is programmed to repeatedly cycle among causing current flow in the first direction, causing current flow in the second direction and causing no current flow.10. The radiation source of claim 6, wherein the controller selectively causes no current flow, to allow the beam to travel undeflected, along a second axis.11. The radiation source of claim 1, wherein the magnet provides a constant magnetic field.12. The radiation source of claim 11, wherein:the magnet has opposing pole portions; the beam of charged particles travels along a path between the opposing pole portions; the beam of charged particles has a width; and the pole portions are configured such that portions of the beam have different path lengths through a magnetic field provided between the pole portions, across the width of the beam. 13. The radiation source of claim 12, wherein the pole portions are irregularly shaped.14. The radiation source of claim 13, wherein the pole portions are triangular.15. The radiation source of claim 14, wherein the pole portions are separated by a varying distance.16. The radiation source of claim 12, wherein:the portions of the beam are differentially deflected by the magnetic field, based, at least in part, on the respective different path lengths. 17. The radiation source of claim 11, wherein the magnet is a permanent magnet.18. The radiation source of claim 11, wherein the magnet is an electromagnet.19. The radiation source of claim 1, wherein:the first chamber and the second chamber have aligned longitudinal axes along which the beam travels; and the target is aligned with the longitudinal axes. 20. The radiation source of claim 1, further comprising:a source of a beam of charged particles supported by the housing to emit the beam into the first chamber. 21. The radiation source of claim 19, wherein:the source of charged particles is a source of a beam of electrons; and impact of the target by the beam causes generation of X-ray radiation. 22. The radiation source of claim 1, wherein the target is tungsten.23. The radiation source of claim 1, wherein the target is elongated along a direction of deflection of the beam.24. The radiation source of claim 1, wherein:the housing has a longitudinal axis; and the radiation is emitted along a central ray transverse to the longitudinal axis. 25. The radiation source of claim 1, wherein:the beam has a width; and the deflection of the beam varies across the width. 26. The radiation source of claim 1, wherein:the magnet selectively deflects the beam onto one of at least one location on the target. 27. A linear accelerator comprising:a housing; an accelerating chamber within the housing, the chamber having an output and a first longitudinal axis aligned with the output; a source of electrons supported by the housing to emit electrons along the first longitudinal axis; a tube comprising a passage having a second longitudinal axis, the tube having a first end with an input coupled to the output of the chamber such that the second longitudinal axis is aligned with the first longitudinal axis; a point target supported within the tube, along a path of the electrons, wherein impact of the target by electrons generates X-ray radiation; and a magnet supported by the housing, the magnet having opposing pole portions facing the tube, to provide a magnetic field through the tube, to deflect the electrons prior to impacting the target. 28. The linear accelerator of claim 27, wherein the magnet provides a time-varying magnetic field during operation.29. The linear accelerator of claim 28, wherein the target comprises a refractory metal.30. The linear accelerator of claim 27, wherein the magnet provides a constant magnetic field during operation.31. A radiation source, comprising:a housing; a source of a beam of charged particles supported by the housing, to emit the beam along a path; a point target supported by the housing along the path of the beam, wherein impact of the beam with the target causes generation of radiation; and a magnet supported by the housing between the source and the target, to provide a magnetic field to change an angle of impact of at least a portion of the beam on the target. 32. The radiation source of claim 31, wherein the magnet provides a constant magnetic field.33. The radiation source of claim 32, wherein the magnetic field varies spatially across a width of the beam.34. The radiation source of claim 31, wherein the magnet provides a time-varying magnetic field.35. A system for examining an object, comprising:a conveyor system to move the object through the system; a radiation source comprising: a housing; a source of a beam of charged particles supported by the housing, to emit the beam along a path; a point target supported by the housing along the path, wherein impact of the beam with the target causes generation of radiation; and a magnet supported by the housing between the source and the target, to provide a magnetic field to deflect at least a portion of the beam prior to the beam impacting the target, the magnet configured to cause a change in an angle of impact of the at least a portion of the beam on the target material, to cause generation of at least one diverging radiation beam for emission by the source; and a detector positioned to receive radiation after interaction with the object, the detector having a size greater than a size of the target; wherein: the radiation source is positioned with respect to the conveying system such that the at least one diverging radiation beam emitted by the source irradiates an object for inspection on the conveying system and is detected by the detector. 36. The system of claim 35, wherein:the radiation source is on a first side of the conveying system; and the detector is on a second side of the conveying system, to detect radiation transmitted through the object. 37. The system of claim 35, wherein the magnet provides a time-varying magnetic field during operation.38. The system of claim 35, wherein the magnet provides a constant magnetic field.39. The system of claim 35, wherein the magnet provides a magnetic field that varies spatially across a width of the beam.40. The system of claim 39, wherein the radiation irradiates the object with substantially uniform intensity.41. The system of claim 35, wherein:the source of charged particles is a source of electrons; and the target material generates X-ray radiation upon impact by the electrons. 42. The system of claim 35, wherein:the radiation source has a first longitudinal axis; and the radiation is emitted along a central ray transverse to the longitudinal axis, to irradiate an object along the central ray. 43. A method of generating radiation, comprising:directing a beam of charged particles towards a point target; deflecting at least a portion of the beam to change an angle of impact of at least a portion of the beam on the point target; impacting the target by the deflected beam to generate a plurality of first diverging radiation beams, at least some of the first diverging radiation beams having a maximum intensity along a different respective ray originating at the target; and collimating the first diverging radiation beams into a plurality of second diverging radiation beams, each having a predetermined share and having a maximum intensity along the respective different ray. 44. The method of claim 43, comprising deflecting the beam by providing a magnetic field.45. The method of claim 43, comprising:deflecting the beam by providing a time-varying magnetic field. 46. The method of claim 43, comprising:deflecting the beam by providing a constant magnetic field. 47. The method of claim 46, comprising:deflecting the beam by passing the beam through a magnetic field varying spatially along a width of the beam. 48. The method of claim 43, comprising:directing the beam along a first axis; deflecting the beam along a second axis transverse to the first axis; impacting the target along the second axis; and generating radiation having a central ray along the second axis. 49. The method of claim 43, comprising:generating X-ray radiation upon impact of the target by the beam. 50. A method of examining contents of an object with a radiation source, the method comprising:directing a beam of charged particles towards a point target; deflecting at least a portion of the beam to change an angle of impact of the at least a portion of the beam on the target; impacting the target by the deflected beam to generate diverging radiation beams; irradiating the object with the diverging radiation beams; and detecting radiation interacting with the object, by a detector having a size greater than a size of the target. 51. The method of claim 50, comprising deflecting the beam by a time-varying magnetic field.52. The method of claim 50, comprising deflecting the beam by a constant magnetic field.53. The method of claim 52, comprising deflecting the beam by a magnetic field varying spatially across a width of the beam.54. The method of claim 50, wherein the beam is an electron beam, the method comprising:impacting the target by the electron beam to generate X-ray radiation. 55. The method of claim 50, comprising:emitting the radiation from a source with a first, longitudinal axis; and irradiating the object with the radiation along a second axis transverse to the first axis. 56. A radiation source, comprising:a housing; a source of a beam of charged particles supported by the housing, to emit the beam along a path, the beam having a width; a point target supported by the housing, wherein impact of the beam with the target causes generation of radiation; and a magnet supported by the housing between the source and the target; wherein the magnet is configured to differentially deflect the beam across the width. 57. The radiation source of claim 56, wherein:the magnet generates a magnetic field that varies spatially across the width of the beam. 58. The radiation source of claim 56, wherein the pole portions are separated by a varying distance.59. The radiation source of claim 56, wherein:the magnet comprises opposing poles, across which the magnetic field is established; the path of the beam passes between the opposing pole portions; and the pole portions are configured such that portions of the beam have different path lengths through the magnetic field, across the width of the beam. 60. The radiation source of claim 59, wherein the pole portions are irregularly shaped.61. A system for examining an object, comprising:a conveyor system to move the object through the system; and a radiation source comprising: a housing; a source of a beam of charged particles supported by the housing, to emit the beam along a path, the beam having a width; a point target supported by the housing along the path, wherein impact of the beam with the target causes generation of radiation; and a magnet supported by the housing between the source and the target, wherein the magnet is configured to differentially deflect the beam across the width; a detector positioned to receive radiation after interaction with the object; wherein: the radiation source is positioned with respect to the conveying system such that radiation emitted by the source irradiates an object for inspection on the conveying system. 62. The system of claim 61, wherein:the source of charged particles is a source of electrons; and the target material generates X-ray radiation upon impact by the electrons. 63. A method of generating radiation, comprising: directing a beam of charged particles towards a point target, the beam having a width;differentially deflecting the beam across the width; and impacting the target by the deflected beam. 64. The method of claim 63, comprising:differentially deflecting the beam by a magnetic field varying spatially across a width of the beam. 65. The method of claim 63, comprising:differentially deflecting the beam across the width, thereby converging or diverging the beam. 66. A method of examining contents of an object with a radiation source, the method comprising:directing a beam of charged particles towards a point target, the beam having a width; differentially deflecting the beam across the width; impacting the target by the deflected beam to generate radiation; irradiating the object with the radiation; and detecting radiation interacting with the object. 67. A system for examining an object, the system, comprising:a conveyor system to move the object through the system; and a radiation source comprising: a housing; a source of a beam of charged particles supported by the housing, to emit the beam along a first axis; a point target supported by the housing, wherein impact of the beam with the target causes generation of radiation; a magnet supported by the housing between the source and the target, the magnet comprising: a core defining first and second opposing pole faces, wherein the core comprises material in which a magnetic field may be induced; a coil around at least a portion of the core; a current source coupled to the coil; and a controller coupled to the current source; wherein: the controller is programmed to: selectively cause current flow in a first direction to generate a magnetic field to deflect the beam along a second axis angled with respect to the first axis, to intercept the target; and to selectively cause at least one of: current flow in a second direction opposite the first direction, to generate a second magnetic field to deflect the beam along a third axis angled with respect to the first and second axes, to intercept the target, to generate a first diverging radiation beam; and no current flow, to allow the beam to travel undeflected along the first axis, to intercept the target, to generate a second diverging radiation beam; the system further comprising: a detector having a size greater than a size of the target, to detect diverging radiation beams interacting with the object. 68. The system of claim 67, wherein:the controller is further programmed to: repeatedly cycle among causing current flow in the first direction, and at least one of causing current flow in the second direction, and causing no current flow.