Combined scatter and transmission multi-view imaging system

• US 9,823,201 B2
• Filed: 05/08/2015
• Issued: 11/21/2017
• Est. Priority Date: 02/03/2012
• Status: Active Grant

• Current Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Original Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Inventors: Morton, Edward James
• Primary Examiner(s): Midkiff, Anastasia
• Application Number:
  US14/707,141
• Publication Number:
  US 20160025890A1
• Time in Patent Office: 928 Days
• CPC Class Codes: G01N 2201/10 Scanning
• CPC Class Codes: G01N 2201/1047 with rotating optics and moving stage
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01N 23/20008 Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor monochromators for X- rays using crystals G21K1/06
• CPC Class Codes: G01N 23/20083 by using a combination of at least two measurements at least one being a transmission measurement and one a scatter measurement
• CPC Class Codes: G01V 5/20 Detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects
• CPC Class Codes: G01V 5/22 Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
• CPC Class Codes: G01V 5/222 measuring scattered radiation
• CPC Class Codes: G01V 5/223 Mixed interrogation beams, e.g. using more than one type of radiation beam
• CPC Class Codes: G01V 5/232 having relative motion between the source, detector and object other than by conveyor G01V5/226 takes precedence
• CPC Class Codes: G01V 5/26 Passive interrogation, i.e. by measuring radiation emitted by objects or goods
• CPC Class Codes: G21K 1/043 changing time structure of beams by mechanical means, e.g. choppers, spinning filter wheels
• CPC Class Codes: H05G 1/70 Circuit arrangements for X-ray tubes with more than one anode; Circuit arrangements for apparatus comprising more than one X ray tube or more than one cathode H05G1/58 takes precedence

Abstract

The present specification discloses a multi-view X-ray inspection system having, in one of several embodiments, a three-view configuration with three X-ray sources. Each X-ray source rotates and is configured to emit a rotating X-ray pencil beam and at least two detector arrays, where each detector array has multiple non-pixellated detectors such that at least a portion of the non-pixellated detectors are oriented toward both the two X-ray sources.

Claims

1. An X-ray inspection system for scanning an object, the X-ray inspection system comprising:

at least two rotating X-ray sources configured to simultaneously emit rotating X-ray beams, wherein each of said at least two rotating X-ray sources comprises a rotary encoder for determining an absolute angle of rotation of the X-ray beams and wherein each of said X-ray beams defines a transmission path;

at least two non-pixelated detector arrays, wherein each of said at least two non-pixelated detector arrays is placed opposite one of the at least two rotating X-ray sources to form a scanning area; and

at least one controller for controlling each of the at least two rotating X-ray sources to scan the object in a coordinated manner and arranged to form an X-ray scan image of the object by recording an intensity of a signal output from each of the at least two non-pixelated detector arrays and the angle of rotation of the X-ray beams.

2. The X-ray inspection system of claim 1, wherein each of the X-ray beams is a pencil beam and wherein each at least two rotating X-ray sources rotates over a predetermined angle of rotation.

3. The X-ray inspection system of claim 1 wherein said at least one controller is configured to simultaneously collect a plurality of scanned views of the object from each detector in the at least two non-pixelated detector arrays being irradiated by no more than one of the X-ray beams at any one time.

4. The X-ray inspection system of claim 1, wherein the controller is configured to causes each of the at least two rotating X-ray sources to begin scanning the object in a direction that does not overlap with an initial scanning direction of other ones of the at least two rotating X-ray sources, thereby eliminating cross talk among the at least two rotating X-ray sources.

5. The X-ray inspection system of claim 1 wherein a volume of the detectors in the at least two non-pixelated detector arrays is independent of a number of scanned views of the object obtained.

6. The X-ray inspection system of claim 1 wherein the X-ray inspection system has an intrinsic spatial resolution and wherein said intrinsic spatial resolution is determined by a degree of collimation of the X-ray beams.

7. The X-ray inspection system of claim 1 wherein the at least two non-pixelated detector arrays comprise an array of scintillator detectors having one or more photomultiplier tubes emerging from an edge of one of the at least two non-pixelated detector arrays to allow X-ray beams from adjacent ones of the at least two rotating X-ray sources to pass an unobstructed face of one of the at least two non-pixelated detector arrays opposite to the photomultiplier tubes.

8. The X-ray inspection system of claim 1 wherein detectors of the at least two non-pixelated detector arrays are gas ionization detectors comprising a Xenon pressurized gas.

9. The X-ray inspection system of claim 1 wherein detectors of the at least two non-pixelated detector arrays comprise at least one of CdZnTe, CdTe, Hgl, Si and Ge.

10. The X-ray inspection system of claim 1, comprising a third rotating X-ray source configured to simultaneously emit X-ray beams with the at least two rotating X-ray sources, wherein a first of the at least two rotating X-ray sources scans the object by starting at a substantially vertical position and moving in a clockwise manner;

wherein a second of the at least two rotating X-ray sources scans the object by starting at a substantially downward vertical position and moving in a clockwise manner; and

wherein the third rotating X-ray source scans the object by starting at a substantially horizontal position and moving in a clockwise manner.

11. The X-ray inspection system of claim 1 wherein the X-ray inspection system is configured to detect gamma rays by turning off the at least two rotating X-ray sources switching detectors in the at least two non-pixelated detector arrays from a current integrating mode to a pulse counting mode.

12. An X-ray inspection system for scanning an object, the inspection system comprising:

a first X-ray source and a second X-ray source configured to simultaneously emit rotating X-ray beams for irradiating the object, wherein each of the first X-ray source and second X-ray source comprises a rotary encoder configured to determine an angle of rotation of the X-ray beams and wherein each of said X-ray beams defines a transmission path;

a non-pixelated detector array comprising at least one transmission detector placed between at least two backscatter detectors, wherein each of said at least two backscatter detectors detects X-rays backscattered by the first X-ray source from a first side of the object and wherein the at least one transmission detector detects transmitted X-rays emitted by the second X-ray source through an opposing side of the object; and

at least one controller configured to control each of the first X-ray sources and second X-ray source to concurrently scan the object in a coordinated manner and configured to generate an X-ray scan image of the object from a signal outputs of the non-pixelated detector array and the angle of rotation of the X-ray beams.

13. The X-ray inspection system as claimed in claim 12 wherein the at least two backscatter detectors have a rectangular profile and the at least one transmission detector has a square profile.

14. The X-ray inspection system as claimed in claim 12 wherein the at least one transmission detector and the at least two backscatter detectors are placed in a single plane facing the object and the at least one transmission detector has a smaller exposed surface area than each of the at least two backscatter detectors.

15. The X-ray inspection system as claimed in claim 12 further comprising a pair of fixed collimators positioned between the at least one transmission detector and one of said at least two backscatter detectors.

16. The X-ray inspection system as claimed in claim 12 wherein each of the first X-ray source and the second X-ray source comprises an extended anode X-ray tube, a rotating collimator assembly, a bearing, and a drive motor.

17. The X-ray inspection system as claimed in claim 12 wherein each of the first X-ray source and the second X-ray source comprises:

an extended anode X-ray tube coupled with a cooling circuit, wherein the extended anode is at ground potential;

a rotating collimator assembly comprising a collimator and at least one collimating ring with slots cut at predefined angles around a circumference of the collimator, wherein a length of each of said slots is greater than a width and an axis of rotation of each of the slots and the width of each of the slots defines an intrinsic spatial resolution of the X-ray inspection system in a direction of a scanning;

a bearing configured to support a weight of the rotating collimator assembly and transfer a drive shaft from the rotating collimator assembly to a drive motor; and

,

a secondary collimator configured to increase spatial resolution in a perpendicular scanning direction.

18. The X-ray inspection system as claimed in claim 17 wherein the at least one controller is configured to receive speed data comprising a speed of the object and, based upon said speed data, adjust at least one of a collimator rotation speed of the first X-ray source or the second X-ray source, a data acquisition rate, or an X-ray tube current of the first X-ray source or the second X-ray source.