Optical device for directing x-rays having a plurality of optical crystals

• US 20050201517A1
• Filed: 02/01/2005
• Published: 09/15/2005
• Est. Priority Date: 08/02/2002
• Status: Active Grant

• Current Assignee: X-Ray Optical Systems Incorporated (Veralto Corp.)
• Original Assignee: X-Ray Optical Systems Incorporated (Veralto Corp.)
• Inventors: Chen, Zewu
• Granted Patent: US 7,035,374 B2
• Time in Patent Office: Days
• US Class Current: 378/84
• CPC Class Codes: G21K 1/06 using diffraction, refraction or reflection, e.g. monochromators G21K1/10, G21K7/00 take precedence

Abstract

Devices for improving the capturing and utilization of high-energy electromagnetic radiation, for example, x-rays, gamma rays, and neutrons, for use in physical, medical, and industrial analysis and control applications are disclosed. The devices include optics having a plurality of optical crystals, for example, doubly-curved silicon or germanium crystals, arranged to optimize the capture and redirection of divergent radiation via Bragg diffraction. In one aspect, a plurality of optic crystals having varying atomic diffraction plane orientations are used to capture and focus divergent x-rays upon a target. In another aspect, a two- or three-dimensional matrix of crystals is positioned relative to an x-ray source to capture and focus divergent x-rays in three dimensions.

Claims

1. An optical device for directing x-rays, the optical device comprising:

a plurality of curved optical crystals positioned according to an x-ray source and an x-ray target to define at least one Rowland circle of radius R and a source-to-target line;

wherein the optical device provides focusing of x-rays from the source to the target; and

wherein the plurality of curved optical crystals have a radius at the plane of the Rowland circle different than R.

2. The optical device of claim 1, wherein the plurality of curved optical crystals have a radius at the plane of the Rowland circle of about 2R.

3. The optical device of claim 2, wherein at least one of the plurality of optical crystals comprises a surface upon which x-rays are directed, and wherein at least one of the plurality of optical crystals comprises a set of atomic diffraction planes having a Bragg angle θ

_B and oriented at an angle γ

with the surface of the at least one of the plurality of optical crystals, and wherein a line drawn from the x-ray source to a point on the surface of the at least one of the plurality of optical crystals makes an angle θ

_B+γ

with the source-to-target line.

4. The optical device of claim 3, wherein the line drawn from the x-ray source to a point on the surface of the at least one of the plurality of optical crystals comprises a line drawn from the x-ray source to the midpoint of the surface of the at least one of the plurality of optical crystals.

5. The optical device of claim 3, wherein the line drawn from the x-ray source to a point on the surface of the at least one of the plurality of optical crystals comprises a line drawn from the x-ray source to about the point of tangency of the surface of the at least one of the plurality of optical crystals and the Rowland circle of the at least one of the plurality of optical crystals.

6. The optical device of claim 1, wherein at least one of the crystals is a doubly-curved crystal.

7. The optical device of claim 6, wherein at least one of the crystals is a toroidal doubly-curved crystal.

8. The optical device of claim 1, in combination with a source of x-rays.

9. The optical device of claim 1, wherein the optical device comprises a toroidal angle about the source-to-target line of at least about 90 degrees.

10. The optical device of claim 9, wherein the optical device comprises a toroidal angle about the source-to-target line of at least about 180 degrees.

11. The optical device of claim 10, wherein the optical device comprises a toroidal angle about the source-to-target line of at least about 270 degrees.

12. The optical device of claim 11, wherein the optical device comprises a toroidal angle about the source-to-target line of about 360 degrees.

13. A method for directing x-rays, comprising:

providing an optical device, the optical device comprising a plurality of curved optical crystals arranged in a matrix, the matrix being positionable to define at least one Rowland circle of radius R with an x-ray source and an x-ray target, and wherein the matrix comprises a plurality of rows, with each row comprising multiple optical crystals of said plurality of optical crystals, wherein the plurality of curved optical crystals have a radius at the plane of the Rowland circle different than R; and

positioning the optical device wherein at least some x-rays from the x-ray source are directed to the x-ray target.

14. The method of claim 13, wherein the plurality of curved optical crystals have a radius at the plane of the Rowland circle of about 2R.

15. The method of claim 13, wherein positioning the optical device comprises positioning the device wherein at least some x-rays emitted by the source impinge at least some of the crystals of the optical device wherein at least some of the x-rays are diffracted.

16. A device for directing x-rays, comprising a first curved crystal and at least one second curved crystal spaced from the first crystal, the first and at least one second curved crystal each comprising at least one lattice plane, and the first curved crystal and the at least one second curved crystal being positionable to define at least one Rowland circle of radius R with an x-ray source and an x-ray target, wherein at least some x-rays impinging upon the first curved crystal and the at least one second curved crystal are directed to the target, and wherein an angle of the at least one lattice plane of the first crystal relative to a surface of the first crystal is different from an angle of the at least one lattice plane of the at least one second crystal relative to a surface of the at least one second crystal.

17. The device of claim 16, wherein the angle of the lattice planes of the first crystal relative to the surface of the first crystal is about zero.

18. The device of claim 16, wherein the angle of the at least one lattice plane of the at least one second crystal relative to the surface of the at least one second crystal is at least about 5 degrees greater than the angle of the at least one lattice plane of the first crystal relative to the surface of the first crystal.

19. The device of claim 16, wherein a line directed from the x-ray source to the center of a surface of the first curved crystal and a line directed from the x-ray source to the center of a surface of the at least one second crystal define an angle γ

.

20. The device of claim 19, wherein the angle of the at least one lattice plane of the at least one second crystal relative to the surface of the at least one second crystal is about γ

.

21. The device of claim 20, wherein the angle γ

is between about minus 15 degrees and about plus 15 degrees.

22. The device of claim 16, wherein the first curved crystal and the at least one second crystal comprise a first set of crystals, and the device further comprises at least one second set of crystals which are also positioned to define a Rowland circle with the x-ray source and the x-ray target, wherein at least some x-rays which impinge upon the at least one second set of crystals are directed to the x-ray target, the target being common with the first set of crystals, and wherein the second set of crystals is spaced from the first set of crystals in a direction orthogonal to a plane of the Rowland circle of the first set of crystals.