Energy Discriminating Scatter Imaging System

• US 20080267353A1
• Filed: 06/15/2006
• Published: 10/30/2008
• Est. Priority Date: 06/16/2005
• Status: Active Grant

• Current Assignee: EV Products Incorporated (Kromek Group PLC)
• Original Assignee: II-VI Incorporated
• Inventors: Rundle, David S.
• Granted Patent: US 7,738,631 B2
• Time in Patent Office: Days
• US Class Current: 378/87
• CPC Class Codes: G01N 21/49 within a body or fluid
• CPC Class Codes: G01N 33/12 Meat; fish

Abstract

A specimen inspection system includes a photon source for outputting photons along a transmission path and a conveyor for translating a specimen completely through the transmission path. A radiation detector is positioned offset with respect to the transmission path for detecting photons that are scattered from the transmission path in response to interaction with the specimen passing therethrough. A controller determines from the detected scattered photons that a first material is present in the specimen.

Claims

1. A specimen inspection system comprising:

means for outputting photons along a transmission path;

means for translating a specimen completely through the transmission path;

means positioned offset with respect to the transmission path for detecting photons that are scattered from the transmission path in response to interaction with the specimen passing therethrough; and

means for determining from the detected scattered photons that a first material is present in the specimen, wherein;

the specimen is comprised of a plurality of materials;

at least two of said plurality of materials, including the first material, block the passage of photons on the transmission path to approximately the same extent whereupon discrimination between said at least two materials based on photons exiting the specimen on the transmission path is prevented; and

the detected scattered photons are scattered in response to interaction with the first material.

2. The system of claim 1, further including means positioned in the transmission path for detecting photons exiting the specimen on the transmission path.

3. The system of claim 2, wherein:

the plurality of materials includes a second material that blocks the passage photons on the transmission path to a greater extent than the first material; and

the means for determining determines from the detected photons that exit the specimen on the transmission path that the second material is present in the specimen.

4. The system of claim 3, wherein:

the means for outputting photons is an x-ray source;

the first material is plastic; and

the second material is metal.

5. The system of claim 1, wherein the means for detecting detects at least one of coherent scattered photons and Compton scattered photons.

6. The system of claim 1, wherein the means for detecting includes a first photon detector positioned at a first angle with respect to the transmission path.

7. The system of claim 6, wherein the means for detecting includes a second photon detector positioned at a second angle with respect to the transmission path.

8. The system of claim 7, wherein the first and second detectors are positioned to detect coherent and Compton scattered photons, respectively.

9. The system of claim 1, wherein the means for detecting comprises a linear array of photon detectors operable at room temperature.

10. The system of claim 9, wherein the linear array of photon detectors comprises:

a core material that produces electron-hole pairs in response to interaction with incident photons;

a first electrode positioned on one surface of said core material; and

a plurality of second electrodes positioned on another surface of said core material opposite said first electrode.

11. The system of claim 10, wherein the core material is comprised of either Cadmium Telluride or Cadmium Zinc Telluride.

12. A method of specimen inspection comprising:

(a) outputting photons along a transmission path;

(b) translating a specimen completely through the transmission path;

(c) detecting photons that are scattered from the transmission path in response to interaction with the specimen passing therethrough; and

(d) determining from the detected scattered photons that a first material is present in the specimen, wherein;

the specimen is comprised of a plurality of materials;

at least two of said plurality of materials, including the first material, block the passage of photons on the transmission path to approximately the same extent whereupon discrimination between said at least two materials based on photons exiting the specimen on the transmission path is prevented; and

the detected scattered photons are scattered in response to interaction with the first material.

13. The method of claim 12, further including detecting photons exiting the specimen on the transmission path.

14. The method of claim 13, further including determining from the detected photons that exit the specimen on the transmission path that a second material, that blocks the passage photons on the transmission path to a greater extent than the first material, is present in the specimen.

15. The method of claim 12, wherein step (c) includes detecting coherent scattered photons and/or Compton scattered photons.

16. A specimen inspection system comprising:

a combination radiation source and collimator for outputting photons along a fan shaped transmission path;

a photon detector positioned offset with respect to the transmission path for detecting photons that are scattered from the transmission path in response to interaction with a slice of a specimen defined by and disposed completely in the transmission path; and

means for determining from the detected scattered photons that a first material is present in the specimen, wherein;

the specimen is comprised of the first material and a second material that block the passage of photons on the transmission path to approximately the same extent whereupon discrimination between the first and second materials based on photons exiting the specimen on the transmission path is prevented; and

the detected scattered photons are scattered in response to interaction with the first material.

17. The system of claim 16, further including another photon detector positioned in the transmission path for detecting photons exiting the specimen on the transmission path.

18. The system of claim 17, wherein:

the second material blocks the passage photons on the transmission path to a greater extent than the first material; and

the means for determining determines from the detected photons that exit the specimen on the transmission path that the second material is present in the specimen.

19. The system of claim 16, wherein the photon detector detects at least one of coherent scattered photons and Compton scattered photons.

20. The system of claim 16, wherein:

the photon detector is positioned at a first angle with respect to the transmission path; and

the system includes another photon detector positioned at a second angle with respect to the transmission path.