COMPACT SCANNED ELECTRON-BEAM X-RAY SOURCE
First Claim
Patent Images
1. An x-ray beam device comprising:
- an electron gun adapted to generate an electron beam;
a drift tube comprising an input end, an output end, and an evacuated region, wherein the input end is operatively coupled to the electron gun, and the evacuated region is adapted to receive the electron beam from the electron gun;
a target situated along a length of the drift tube and extending in a direction substantially parallel to a direction of travel of the electron beam, wherein the target is adapted to emit x-rays when struck by the electron beam;
at least one bending magnet assembly situated adjacent to the drift tube wherein the at least one bending magnet assembly is adapted to selectively produce a magnetic field extending through the drift tube in a direction substantially perpendicular to the direction of travel of the electron beam to cause the electron beam to selectively bend and strike the target;
a collector operatively coupled to the output end of the drift tube and adapted to collect the electron beam when the at least one bending magnet assembly does not cause the electron beam to bend and strike the target; and
a controller adapted to control the at least one bending magnet assembly to cause the magnetic field extending through the drift tube to move along a length of the drift tube in at least one of a first direction from the electron gun to the collector and a second direction from the collector to the electron gun.
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Accused Products
Abstract
A compact, reliable scanning electron-beam x-ray source achieves reduced complexity and cost. In particular, the x-ray source includes an electron beam that is propagated parallel to an x-ray target and is swept across the target in response to a moving magnetic cross field. Rather than scanning the beam by deflecting it about a single point, the point of deflection is translated along the target length, dramatically reducing the volume of the device. The magnetic cross field is translated along the target length using either mechanical systems to move permanent magnets, or electrical systems to energize an array of electromagnets.
42 Citations
18 Claims
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1. An x-ray beam device comprising:
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an electron gun adapted to generate an electron beam; a drift tube comprising an input end, an output end, and an evacuated region, wherein the input end is operatively coupled to the electron gun, and the evacuated region is adapted to receive the electron beam from the electron gun; a target situated along a length of the drift tube and extending in a direction substantially parallel to a direction of travel of the electron beam, wherein the target is adapted to emit x-rays when struck by the electron beam; at least one bending magnet assembly situated adjacent to the drift tube wherein the at least one bending magnet assembly is adapted to selectively produce a magnetic field extending through the drift tube in a direction substantially perpendicular to the direction of travel of the electron beam to cause the electron beam to selectively bend and strike the target; a collector operatively coupled to the output end of the drift tube and adapted to collect the electron beam when the at least one bending magnet assembly does not cause the electron beam to bend and strike the target; and a controller adapted to control the at least one bending magnet assembly to cause the magnetic field extending through the drift tube to move along a length of the drift tube in at least one of a first direction from the electron gun to the collector and a second direction from the collector to the electron gun. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. In an x-ray beam device comprising an x-ray target, a drift tube, an electron beam propagating through the drift tube, and an array of electromagnets positioned adjacent to the drift tube, a method of controlling a magnetic field inside the drift tube comprises:
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applying a first current to a first element of the array of electromagnets to cause the electron beam to bend into the target at a first location situated near the first element of the array of electromagnets; applying a second current to a second element of the array of electromagnets; ramping down the first current through the first element of the array of electromagnets until the current reaches zero to cause the electron beam to bend into the target at a second location situated near the second element of the array of electromagnets; applying a third current to a third element of the array of electromagnets; and ramping down the second current through the second element of the array of electromagnets until the current reaches zero to cause the electron beam to bend into the target at a third location situated near the third element of the array of electromagnets. - View Dependent Claims (15, 16)
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17. In an x-ray beam device comprising an x-ray target, a drift tube, an electron beam propagating through the drift tube, and an array of electromagnets positioned adjacent to the drift tube, a method of controlling a magnetic field inside the drift tube comprises:
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calculating a first normal distribution of current to apply to each of a plurality of elements of the array of electromagnets such that a peak of the first normal distribution is at a first location along a length of the drift tube; applying corresponding amounts of current consistent with the first normal distribution through each of the plurality of elements of the array of electromagnets to cause the electron beam to bend into the target near the first location along the drift tube; calculating a second normal distribution of current to apply to each of the plurality of elements of the array of electromagnets such that a peak of the second normal distribution is at a second location along the length of the drift tube; and applying corresponding amounts of current consistent with the second normal distribution through each of the plurality of elements of the array of electromagnets to cause the electron beam to bend into the target near the second location along the drift tube. - View Dependent Claims (18)
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Specification