X-RAY DIFFRACTION DEVICE, OBJECT IMAGING SYSTEM, AND METHOD FOR OPERATING A SECURITY SYSTEM

• US 20100226478A1
• Filed: 03/05/2009
• Published: 09/09/2010
• Est. Priority Date: 03/05/2009
• Status: Active Grant

• Current Assignee: Morpho Detection (Safran SA)
• Original Assignee: Morpho Detection (Safran SA)
• Inventors: Gordon, Jeffrey Seymour, Harding, Geoffrey, Kosciesza, Dirk, Olesinski, Stephan, Strecker, Helmut Rudolf
• Granted Patent: US 7,813,477 B2
• Time in Patent Office: Days
• US Class Current: 378/70
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation

Abstract

An x-ray diffraction imaging device includes at least one x-ray detector and at least one scatter collimator positioned upstream of the at least one x-ray detector. The at least one collimator includes a plurality of successive plates. Each of the plurality of plates defines a plurality of rectangular holes. The plurality of successive plates are arranged such that the plurality of rectangular holes define a plurality of quadrilateral passages extending through the at least one scatter collimator. Each of the plurality of quadrilateral passages is configured to increase a rate of detection of first x-rays that define an x-ray transit path enclosed within a single such quadrilateral passage. Also, the plurality of quadrilateral passages is configured to decrease a rate of detection of second x-rays that define an x-ray transit path that intersects more than one such quadrilateral passage.

Claims

1. An x-ray diffraction imaging device, comprising:

at least one x-ray detector; and

at least one scatter collimator positioned upstream of said at least one x-ray detector, said at least one scatter collimator comprising a plurality of successive plates, each successive plate of said plurality of successive plates defining a plurality of rectangular holes, each rectangular hole of the plurality of rectangular holes includes a first dimension and a substantially orthogonal second dimension that does not equal the first dimension, wherein the first dimension increases and the second dimension is substantially constant with said each successive plate in a direction towards said at least one x-ray detector, said plurality of successive plates arranged such that the plurality of rectangular holes define a plurality of widening quadrilateral passages extending through said at least one scatter collimator, wherein each of the plurality of widening quadrilateral passages is configured to increase a rate of detection of first x-rays that define an x-ray transit path enclosed within a single such widening quadrilateral passage, and the plurality of widening quadrilateral passages is configured to decrease a rate of detection of second x-rays that define an x-ray transit path that intersects more than one such widening quadrilateral passage.

2. The x-ray diffraction imaging device of claim 1 wherein said each successive plate of said plurality of successive plates is separated by a predetermined plate pitch, wherein the predetermined plate pitch is configured to decrease the rate of detection of the second x-rays, such second x-rays are cross-talk x-rays.

3. The x-ray diffraction imaging device of claim 1 wherein said plurality of successive plates comprises:

a first plate defining a plurality of rectangular first holes, each of the first holes having a first dimensional value parallel to a y-axis; and

a second plate positioned downstream of said first plate, said second plate defining a plurality of rectangular second holes, each of the second holes having a second dimensional value parallel to the y-axis that is greater than the first dimensional value parallel to the y-axis in a ratio at least partially defined by a separation of said second plate and said first plate from an x-ray source.

4. The x-ray diffraction imaging device of claim 3 wherein said each successive plate of said plurality of successive plates defines a plurality of successive holes, each successive hole having:

a constant dimensional value parallel to a z-axis; and

a successively increasing dimensional value parallel to the y-axis.

5. The x-ray diffraction imaging device of claim 4 wherein said at least one x-ray detector includes a rectangular hole length value parallel to the y-axis determined by the mathematical expression:

b=sqrt[8aA],

wherein “

b”

represents the rectangular hole length value parallel to the y-axis of said at least one x-ray detector, “

a”

represents a rectangular hole height parallel to the z-axis of said at least one x-ray detector, and “

A”

represents a displacement distance value of said at least one x-ray detector away from a primary x-ray beam trajectory that is substantially orthogonal to a plane at least partially defined by said at least one x-ray detector.

6. The x-ray diffraction imaging device of claim 5 wherein each of the plurality of widening quadrilateral passages extending through said at least one scatter collimator has a constant rectangular hole height value of “

a” and

an increasing rectangular hole length value that approaches a value of “

b”

that represents a rectangular hole length value of a rectangular hole adjacent to said at least one x-ray detector.

7. An object imaging system, comprising:

at least one computer processor; and

an x-ray diffraction imaging device coupled to said at least one computer processor, said x-ray diffraction imaging device comprising;

at least one x-ray detector; and

at least one scatter collimator positioned upstream of said at least one x-ray detector, said at least one scatter collimator comprising a plurality of successive plates, each successive plate of said plurality of successive plates defining a plurality of rectangular holes, each rectangular hole of the plurality of rectangular holes includes a first dimension and a substantially orthogonal second dimension that does not equal the first dimension, wherein the first dimension increases and the second dimension is substantially constant with said each successive plate in a direction towards said at least one x-ray detector, said plurality of successive plates arranged such that the plurality of rectangular holes define a plurality of widening quadrilateral passages extending through said at least one scatter collimator, wherein each of the plurality of widening quadrilateral passages is configured to increase a rate of detection of first x-rays that define an x-ray transit path enclosed within a single such widening quadrilateral passage, and the plurality of widening quadrilateral passages is configured to decrease a rate of detection of second x-rays that define an x-ray transit path that intersects more than one such widening quadrilateral passage.

8. The object imaging system of claim 7 wherein said each successive plate of said plurality of successive plates is separated by a predetermined plate pitch, wherein the predetermined plate pitch is configured to decrease the rate of detection of the second x-rays, such second x-rays are cross-talk x-rays.

9. The object imaging system of claim 7 wherein said plurality of successive plates comprises:

a first plate defining a plurality of rectangular first holes, each of the first holes having a first dimensional value parallel to a y-axis; and

a second plate positioned downstream of said first plate, said second plate defining a plurality of rectangular second holes, each of the second holes having a second dimensional value parallel to the y-axis that is greater than the first dimensional value parallel to the y-axis in a ratio at least partially defined by a separation of said second plate and said first plate from an x-ray source.

10. The object imaging system of claim 9 wherein said each successive plate of said plurality of successive plates defines a plurality of successive holes, each successive hole having:

a constant dimensional value parallel to a z-axis; and

a successively increasing dimensional value parallel to the y-axis.

11. The object imaging system of claim 10 wherein said plurality of successive plates defines a detection solid angle and a constant angular broadening.

12. The object imaging system of claim 10 wherein said at least one x-ray detector includes a rectangular hole length value parallel to the y-axis determined by the mathematical expression:

b=sqrt[8aA],

wherein “

b”

represents the rectangular hole length value parallel to the y-axis of said at least one x-ray detector, “

a”

represents a rectangular hole height parallel to the z-axis of said at least one x-ray detector, and “

A”

represents a displacement distance value of said at least one x-ray detector away from a primary x-ray beam trajectory that is substantially orthogonal to a plane at least partially defined by said at least one x-ray detector.

13. The object imaging system of claim 10 wherein the plurality of widening quadrilateral passages extending through said at least one scatter collimator have a constant dimensional value parallel to the z-axis and an increasing dimensional value parallel to the y-axis.

14. The object imaging system of claim 7 wherein:

said at least one detector is configured to generate a plurality of energy spectra from a two-dimensional distribution of voxels of an object; and

said at least one computer processor is programmed to analyze the plurality of energy spectra from the two-dimensional distribution of voxels in parallel to generate a three-dimensional x-ray diffraction image of the object.

15. A method for operating a security system, said method comprising:

directing an x-ray fan-beam from a substantially stationary x-ray source toward a substantially stationary x-ray detector with at least one object positioned therebetween;

scattering at least a portion of the x-ray fan-beam within at least a portion of the at least one object, thereby forming an x-ray scatter beam; and

transmitting at least a portion of the x-ray scatter beam through a plurality of widening quadrilateral passages positioned upstream of the x-ray detector, wherein the plurality of widening quadrilateral passages are at least partially defined via a plurality of successive plates, each successive plate of the plurality of successive plates defines a plurality of rectangular holes, each rectangular hole of the plurality of rectangular holes includes a first dimension and a substantially orthogonal second dimension that does not equal the first dimension, wherein the first dimension increases and the second dimension is substantially constant with each successive plate in a direction towards the at least one x-ray detector, wherein each of the plurality of widening quadrilateral passages is configured to increase a rate of detection of first x-rays that define an x-ray transit path enclosed within a single such widening quadrilateral passage, and the plurality of widening quadrilateral passages is configured to decrease a rate of detection of second x-rays that define an x-ray transit path that intersects more than one such widening quadrilateral passage.

16. The method of claim 15 wherein directing an x-ray fan-beam from a substantially stationary x-ray source toward a substantially stationary x-ray detector with at least one object positioned therebetween comprises illuminating at least a portion of the object with x-rays at a rate of at least approximately 10,000 object volume elements (voxels) per second.

17. The method of claim 16 wherein scattering at least a portion of the x-ray fan-beam within at least a portion of the at least one object comprises:

scattering at least a portion of the x-ray fan beam from the object toward a scatter collimator, thereby generating a plurality of scatter x-rays within at least a portion of the object; and

transmitting at least a portion of the plurality of scatter x-rays through the scatter collimator.

18. The method of claim 17 wherein transmitting at least a portion of the plurality of scatter x-rays through the scatter collimator comprises:

absorbing at least a portion of cross-talk scatter x-rays within the scatter collimator; and

transmitting at least a portion of legitimate scatter x-rays to at least a portion of the substantially stationary x-ray detector.

19. The method of claim 15 wherein transmitting at least a portion of the x-ray fan-beam through a plurality of quadrilateral passages positioned upstream of the x-ray detector comprises transmitting at least a portion of the x-ray fan-beam through a plurality of quadrilateral passages extending through at least a portion of a scatter collimator, thereby facilitating constant angular broadening of the at least a portion of the x-ray fan-beam.

20. The method of claim 15 wherein directing an x-ray fan-beam from a substantially stationary x-ray source toward a substantially stationary x-ray detector with at least one object positioned therebetween comprises:

generating a plurality of energy spectra from a two-dimensional distribution of voxels of the object; and

analyzing the plurality of energy spectra from the two-dimensional distribution of voxels in parallel to generate a three-dimensional x-ray diffraction image of the object.