X-ray scanners and X-ray sources therefor

• US 8,625,735 B2
• Filed: 04/14/2011
• Issued: 01/07/2014
• Est. Priority Date: 12/16/2005
• 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): Artman, Thomas R
• Application Number:
  US13/086,708
• Publication Number:
  US 20120326029A1
• Time in Patent Office: 999 Days
• Field of Search: 378/5, 378/9, 378/10
• US Class Current: 378/5
• CPC Class Codes: A61B 6/4042 K-edge filters
• CPC Class Codes: A61B 6/482 involving multiple energy imaging
• CPC Class Codes: G01N 2223/206 sources operating at different energy levels
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01N 23/06 and measuring the absorption
• CPC Class Codes: G01N 23/087 using polyenergetic X-rays
• CPC Class Codes: G01V 5/00 Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
• CPC Class Codes: H01J 2235/086 Target geometry
• CPC Class Codes: H01J 2235/088 Laminated targets, e.g. plurality of emitting layers of unique or differing materials
• CPC Class Codes: H01J 35/112 Non-rotating anodes H01J35/12 takes precedence

Abstract

The present invention is directed toward an X-ray scanner that has an electron source and an anode. The anode has a target surface with a series of material areas spaced along it in a scanning direction. The material areas are formed from different materials. The electron source is arranged to direct electrons at a series of target areas of the target surface, in a predetermined order, so as to generate X-ray beams having different energy spectra.

Claims

1. An X-ray scanner comprising

a first electron source configured to generate a first electron beam;

a second electron source, configured to generate a second electron beam; and

an anode having a target surface comprising a first material and a second material, wherein

said first material is different from said second material,

said first material and second material form a pattern on said target surface, the pattern comprising a rectangular block of the first material alternating with a rectangular block of the second material to form a linear array of alternating target areas in a ring around said scanner,

the first electron source is configured to direct the first electron beam at said first material to generate a first X-ray beam having a first energy spectra

the second electron source is configured to direct the second electron beam at said second material to generate a second X-ray beam having a second energy spectra, said first energy spectra being different than the second energy spectra, and

wherein said first electron beam is offset from said second electron beam by 180 degrees plus an angular displacement between alternating target areas such that target areas on opposing sides of said anode are simultaneously targeted by the first electron beam and second electron beam.

2. The X-ray scanner of claim 1 wherein the first material area is formed of a uniform material.

3. The X-ray scanner of claim 2 wherein the second material area is formed of a uniform material.

4. The X-ray scanner of claim 1 wherein the first material area comprises a strip that extends in a direction transverse to the scanning direction.

5. The X-ray scanner of claim 1 wherein the second material area comprises a strip that extends in a direction transverse to the scanning direction.

6. The X-ray scanner of claim 1 wherein the first material area comprises a strip that extends in a direction which is oblique to the scanning direction.

7. The X-ray scanner of claim 1 wherein the second material area comprises a strip that extends in a direction which is oblique to the scanning direction.

8. The X-ray scanner of claim 1 wherein the first or second material area comprises a thin film of metal.

9. The X-ray scanner of claim 2 further comprising a plurality of detectors arranged to detect the X-ray beams.

10. The X-ray scanner of claim 9 wherein the detectors are substantially identical.

11. The X-ray scanner of claim 9 wherein the detectors comprise a first set of detectors and a second set of detectors and wherein, relative to said second set of detectors, said first set of detectors is more sensitive to X-rays over a first range of energies, and, relative to said first set of detectors, the second set of detectors is more sensitive to X-rays over a second range of energies.

12. The X-ray scanner of claim 11 wherein the second set of detectors comprises a filter material and a detector element.

13. The X-ray scanner of claim 9 wherein the detectors comprise a first set of detectors and a second set of detectors and wherein said first set of detectors has a different response characteristic from said second set of detectors and wherein the first set of detectors is configured to receive X-rays of the first energy spectra and the second set of detectors is configured to receive the X-rays of the second energy spectra.

14. The X-ray scanner of claim 1 further comprising a processor configured to receive signals from detectors and to process the signals to generate an output.

15. The X-ray scanner of claim 14 wherein the output is image data set arranged to generate an image.

16. The X-ray scanner of claim 1 wherein the first and second materials are each arranged to generate X-rays having an intensity peak at two different respective fluorescent energies, and a filter material is arranged to provide different attenuations at the two fluorescent energies.

17. The X-ray scanner of claim 16 wherein the filter material has an absorption edge at a frequency between the two fluorescent energies.