Method and system for performing materials analysis with reflected inelastic scatter

1. A method for performing materials analysis of an object using an X-ray system, said method comprising:

generating an X-ray beam using an X-ray source having an anode;

acquiring a scatter spectrum from Compton scatter produced when the X-ray beam interacts with the object, the scatter spectrum acquired using an energy resolving detector;

extracting a Compton profile from the scatter spectrum by processing the scatter spectrum using a control system of the X-ray system, the Compton profile including peaks at characteristic lines of the anode;

identifying a characteristic of a material of the object using the Compton profile; and

outputting an indication of the characteristic of the material.

2. A method in accordance with claim 1 , wherein acquiring a scatter spectrum from Compton scatter comprises:

irradiating the object with a pencil beam;

collimating the Compton scatter to be a predetermined angle with respect to a direction of the pencil beam; and

recording the scatter spectrum of the Compton scatter at the predetermined angle using the energy resolving detector.

3. A method in accordance with claim 1 , wherein extracting a Compton profile comprises:

normalizing the scatter spectrum;

correcting the normalized scatter spectrum by removing a background signal from the normalized scatter spectrum; and

extracting the Compton profile from the normalized and corrected scatter spectrum.

4. A method in accordance with claim 3 , wherein normalizing the scatter spectrum comprises dividing a number of detected photons in each energy bin within a first predetermined range by a total number of detected photons summed over a plurality of energy bins within a second predetermined range that is different than the first predetermined range.

5. A method in accordance with claim 1 , wherein extracting a Compton profile comprises:

deconvolving the scatter spectrum;

removing a finite energy resolution of the energy resolving detector and a doublet structure of the characteristic lines of the anode from the scatter spectrum; and

yielding features of the scatter spectrum for material identification.

6. A method in accordance with claim 1 , wherein extracting a Compton profile comprises:

assuming a Compton profile for the acquired scatter spectrum;

synthesizing a simulated scatter spectrum from the assumed Compton profile;

comparing the simulated scatter spectrum with the acquired scattered spectrum to produce a difference signal;

iteratively correcting the assumed Compton profile using the difference signal to produce a corrected Compton profile; and

yielding features of the scatter spectrum for material identification based on the corrected Compton profile.

7. A method in accordance with claim 6 , wherein synthesizing a simulated scatter spectrum from the assumed Compton profile comprises superposing a predetermined number of Gaussian functions.

8. A method in accordance with claim 1 , wherein extracting a Compton profile comprises:

processing the scatter spectrum using a plurality of Gaussians, each Gaussian of the plurality of Gaussians including a peak amplitude and a width; and

yielding features of the scatter spectrum for material identification based on the peak amplitudes and the widths of the plurality of Gaussians.

9. An X-ray system for analyzing an object, said X-ray system comprising:

an X-ray source comprising an anode and at least one source focus, said X-ray source configured to generate an X-ray beam at said at least one source focus, said anode configured to generate characteristic lines;

an energy resolving detector positioned with respect to said at least one source focus, said energy resolving detector configured to record Compton scatter produced from the X-ray beam interacting with the object, the Compton scatter at an angle to a direction of the X-ray beam; and

a control system operationally coupled to said X-ray source and said energy resolving detector, said control system configured to:

acquire a scatter spectrum from the Compton scatter using said energy resolving detector;

extract a Compton profile from the scatter spectrum by processing the scatter spectrum, the Compton profile including peaks at the characteristic lines of said anode; and

identify a characteristic of a material of the object using the Compton profile.

10. An X-ray system in accordance with claim 9 , further comprising a primary collimator configured to produce sequentially a plurality of pencil beams from a source focus to scan the object.

11. An X-ray system in accordance with claim 9 , further comprising a secondary collimator configured to collimate the Compton scatter to be at the angle for detection by said energy resolving detector.

12. An X-ray system in accordance with claim 9 , wherein said anode comprises a tungsten (W) anode that generates a W Kα1 line and a W Kα2 line as the characteristic lines.

13. An X-ray system in accordance with claim 9 , wherein said energy resolving detector comprises a Schottky contacted cadmium telluride (CdTe) detector configured to provide energy resolutions of about 1% full width at half maximum (FWHM) at 60 kilo-electronvolts (keV).

14. An X-ray system in accordance with claim 9 , wherein said energy resolving detector comprises a semiconductor detector configured to provide an energy resolution greater than 2% FWHM at 60 keV.

15. An X-ray system in accordance with claim 9 , wherein a Z-axis of said X-ray system defines an axis of symmetry, said at least one source focus and said energy resolving detector positioned on said axis of symmetry.

16. An X-ray system in accordance with claim 9 , further comprising:

an axis of symmetry; and

a primary collimator configured to produce a pencil beam at said at least source focus, said primary collimator rotationally symmetric about said axis of symmetry.

17. An X-ray system in accordance with claim 9 , further comprising:

an axis of symmetry; and

a secondary collimator configured to collimate the Compton scatter to be at the angle, said secondary collimator rotationally symmetric about said axis of symmetry.

18. An X-ray system in accordance with claim 9 , wherein the angle is at least 150°.

19. An X-ray system in accordance with claim 9 , wherein said control system is further configured to:

normalize the scatter spectrum;

correct the normalized scatter spectrum by removing a background signal from the normalized scatter spectrum; and

extract the Compton profile from the normalized and corrected scatter spectrum.

20. An X-ray system in accordance with claim 9 , wherein said control system is further configured to:

process the scatter spectrum using a plurality of Gaussians, each Gaussian of the plurality of Gaussians including a peak amplitude and a width; and

yield features of the scatter spectrum for material identification based on the peak amplitudes and the widths of the plurality of Gaussians.