X-ray tensor tomography system

Patent metadata

Field	Value
Publication number	US-10697902-B2
Application number	US-201716309244-A
Country	US
Kind code	B2
Filing date	Jun 13, 2017
Priority date	Jun 13, 2016
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

The present invention relates to an X-ray tensor tomography (XTT) system ( 34 ), comprising a source ( 12 ) for providing a beam with coherent X-rays, a first grating ( 16 ) with first grating lines and a second grating ( 18 ) with second grating lines, the second grating lines being parallel to the first grating lines and the XTT-system ( 34 ) being configured to relatively shift the first grating ( 16 ) and/or the second grating ( 18 ) in a shifting direction ( 32 ) being parallel to the planes of the gratings ( 16, 18 ), a stage ( 36 ) for rotating the specimen about a first axis of rotation and about not more than two axes of rotation ( 26 ), the first axis of rotation lying in a plane ( 38 ) being tilted by an angle ψ with respect to the to the planes of the gratings ( 16, 18 ), wherein 0°<ψ≤90°, and by an angle β with respect to a plane being orthogonal to the direction of the beam path at a location of the stage ( 36 ), wherein 0°<β<90°, a detector ( 22 ), a reconstruction unit configured to reconstruct scattering tensors for a specimen.

First claim

The invention claimed is:

1. An X-ray tensor tomography (XTT) system, comprising
a source configured for providing a beam with coherent X-rays along a beam path;
an interferometer arranged along the beam path downstream the source and comprising a first grating with first grating lines and a second grating with second grating lines, wherein:
the second grating lines are parallel to the first grating lines,
the XTT-system is configured to relatively shift the first grating and the second grating with respect to each other in a shifting direction into different grating positions, wherein the shifting direction is parallel to the planes of the gratings;

a stage configured for mounting a specimen in the beam path downstream the source, wherein the stage is designed adapted to rotate the specimen about at least one first axis of rotation and about not more than two axes of rotation for orienting the specimen in the beam path and with respect to the beam path, wherein the first axis of rotation lies in a plane which is tilted:
by an angle ψ with respect to the to the planes of the gratings wherein 0°<ψ<90°, and
by an angle β with respect to a plane being orthogonal to the direction of the beam path at a location of the stage, wherein 0°<β<90°,

a detector arranged downstream the source and the interferometer and configured for acquiring a sequence of two-dimensional intensity distributions of X-rays of the beam,
a reconstruction unit configured to reconstruct scattering tensors for a specimen containing on or more structures capable of scattering X-rays, wherein the scattering tensors provide information about the three-dimensional position of the one or more structures and about an orientation of the one or more structures, based on:
a sequence of two-dimensional intensity distributions acquired for different orientations of the specimen and for different grating positions, and on
the orientations and grating positions, for which the sequence of two-dimensional intensity distributions is acquired.

2. The XTT-system of claim 1 , wherein the source is configured for providing the beam along an optical axis of the XTT-system, and wherein the second grating lines and the first grating lines are orthogonal to the optical axis, and/or wherein the shifting direction is orthogonal to the grating lines.

3. The XTT-system of claim 1 , wherein the angle ψ is 10°<ψ<70°.

4. The XTT-system of claim 1 , wherein the stage is adapted to rotate the specimen about a second axis of rotation.

5. The XTT-system of claim 4 , wherein the second axis of rotation is orthogonal to the first axis of rotation.

6. The XTT-system of claim 4 , wherein the second axis of rotation is stationary with respect to the source and the detector and wherein during a rotation about the second axis of rotation by an angle Δθ the first axis of rotation is rotated by the same angle Δθ within a plane being orthogonal to the second axis of rotation.

7. The XTT-system of claim 1 , wherein one of the stage and the XTT-system is adapted to rotate the specimen about only the first axis of rotation, and wherein the first axis of rotation is tilted with respect to the direction being parallel to the grating planes and orthogonal to the grating lines by an angle α, with 0°<α<180°.

8. The XTT-system of claim 7 , wherein the first axis of rotation is stationary with respect to the source and the detector.

9. The XTT-system of claim 7 , wherein 20°<α<70°.

10. The XTT-system of claim 7 , wherein 35°<α<55°.

11. The XTT-system of claim 1 , wherein the first and second gratings are arranged in parallel planes.

12. The XTT-system of claim 1 , wherein the source comprises an X-ray source and a third grating with grating lines parallel to the first and second grating lines.

13. A method for reconstructing scattering tensors for a specimen by using the XTT-system of claim 1 , wherein the sequence of two-dimensional intensity distributions is acquired for a scanning process comprising
rotating the specimen about the first axis of rotation to at least 50, preferably to at least 80 different first rotational positions covering an angle range from 0° to 360°.

14. A method for reconstructing scattering tensors for a specimen by using the XTT-system of claim 1 , wherein the scanning process further comprises:
rotating the specimen about the second axis of rotation to at least 3 different second rotational positions covering an angle range from 0° to 180°, wherein for each of said different second rotational positions the specimen is rotated about the first axis of rotation to at least 50 different first rotational positions covering an angle range from 0° to 360°.

15. A method for reconstructing scattering tensors for a specimen by using the XTT-system of claim 1 , wherein one or both of the first and/or second rotational positions are evenly distributed over the respective angle range.

16. The XTT-system of claim 1 , wherein 30°<ψ<50°.

17. The XTT-system of claim 1 , wherein the first and second gratings are line gratings.

18. An X-ray tensor tomography (XTT) system, comprising
a source for providing a beam with coherent X-rays along a beam path;
an interferometer arranged along the beam path downstream the source comprising a first grating with first grating lines and a second grating with second grating lines, wherein:
the second grating lines are parallel to the first grating lines,
the XTT-system is configured to relatively shift the first grating and the second grating with respect to each other in a shifting direction into different grating positions, wherein the shifting direction is parallel to the planes of the gratings;

a stage for mounting a specimen in the beam path downstream the source, wherein the stage is designed to rotate the specimen about at least one first axis of rotation and about not more than two axes of rotation for orienting the specimen in the beam path and with respect to the beam path, wherein the first axis of rotation lies in a plane which is tilted:
by an angle ψ with respect to the to the planes of the gratings, wherein 0°<ψ<90°, and
by an angle β with respect to a plane being orthogonal to the direction of the beam path at a location of the stage, wherein 0°<β<90°;

a detector arranged downstream the source and the interferometer for acquiring a sequence of two-dimensional intensity distributions of X-rays of the beam;
a reconstruction unit configured to reconstruct scattering tensors for a specimen containing on or more structures capable of scattering X-rays, wherein the scattering tensors provide information about the three-dimensional position of the one or more structures and about an orientation of the one or more structures, based on:
a sequence of two-dimensional intensity distributions acquired for different orientations of the specimen and for different grating positions, and on
the orientations and grating positions, for which the sequence of two-dimensional intensity distributions is acquired;

wherein the stage is designed to rotate the specimen about a second axis of rotation;
wherein the second axis of rotation is orthogonal to the first axis of rotation;
wherein the second axis of rotation is stationary with respect to the source and the detector; and
wherein during a rotation about the second axis of rotation by an angle Δθ the first axis of rotation is rotated by the same angle Δθ within a plane being orthogonal to the second axis of rotation.

Assignees

• Univ Muenchen Tech

Inventors

• Sharma Yash
• Lasser Tobias
• Pfeiffer Franz

Classifications

• G01N2223/419

  computed tomograph · CPC title

• G01N23/20075

  by measuring interferences of X-rays, e.g. Borrmann effect · CPC title

• G01N23/201

  by measuring small-angle scattering · CPC title

• G01N23/046 Primary

  using tomography, e.g. computed tomography [CT] · CPC title