Method and apparatus for x-ray microscopy

Patent metadata

Field	Value
Publication number	US-10352880-B2
Application number	US-201715605957-A
Country	US
Kind code	B2
Filing date	May 26, 2017
Priority date	Apr 29, 2015
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

This disclosure presents systems for x-ray microscopy using an array of micro-beams having a micro- or nano-scale beam intensity profile to provide selective illumination of micro- or nano-scale regions of an object. An array detector is positioned such that each pixel of the detector only detects x-rays corresponding to a single micro- or nano-beam. This allows the signal arising from each x-ray detector pixel to be identified with the specific, limited micro- or nano-scale region illuminated, allowing sampled transmission image of the object at a micro- or nano-scale to be generated while using a detector with pixels having a larger size and scale. Detectors with higher quantum efficiency may therefore be used, since the lateral resolution is provided solely by the dimensions of the micro- or nano-beams. The micro- or nano-scale beams may be generated using an arrayed x-ray source or a set of Talbot interference fringes.

First claim

We claim:

1. A method of examining an object with x-rays, comprising:
creating a periodic array of x-ray micro-beams propagating from a common x-ray source, with each x-ray micro-beam at the object having an axis along which the x-ray micro-beam propagates, and having a contrast between the x-ray intensity along the axis and the x-ray intensity at a distance equal to ½ of the period of said periodic array of x-ray micro-beams measured perpendicularly from said axis of greater than 10%;
positioning an x-ray pixel array detector system comprising a plurality of pixels so that each pixel detects x-rays corresponding to no more than one x-ray micro-beam;
illuminating a portion of said object with said periodic array of x-ray micro-beams; and
recording signals produced by said x-ray pixel array detector system.

2. The method of claim 1 , wherein the periodic array of x-ray micro-beams is created through Talbot interference phenomena that form a Talbot interference pattern; and said x-ray micro-beams correspond to an array of constructive interference portions of the Talbot interference pattern.

3. The method of claim 2 , additionally comprising:
positioning an absorbing masking component having periodic transmissive portions that transmit only a predetermined subset of the x-ray micro-beams; wherein the period of said transmissive portions in both lateral directions is equal to the period of the Talbot interference pattern multiplied by a positive integer N; and
aligning said absorbing masking component so that said transmissive portions are centered with every Nth x-ray micro-beam.

4. The method of claim 1 , additionally comprising positioning placing an absorbing masking component having transmissive portions to transmit only a predetermined subset of the x-ray micro-beams.

5. The method of claim 4 , wherein the lateral dimensions of said transmissive portions are less than ¾ of the period of the periodic array of the x-ray micro-beams.

6. The method of claim 1 , additionally comprising positioning the x-ray pixel array detector system so that two or more pixels detect x-rays corresponding to the same x-ray micro-beam.

7. The method of claim 1 , wherein the signals correspond to the transmission of said x-ray micro-beams through the object.

8. The method of claim 1 , wherein the signals correspond to an interaction phenomenon of said x-ray micro-beams with the object, said interaction phenomenon selected from the group consisting of: absorption, refraction, x-ray fluorescence, and small angle scattering.

9. The method of claim 1 , wherein the x-ray pixel array detector system comprises a first x-ray detector having periodic x-ray active areas positioned to detect x-rays and to produce signals corresponding to said x-rays, the periodic x-ray active areas separated by x-ray inactive areas that do not produce signals, with the period of said periodic x-ray active areas configured to detect only a predetermined subset of the x-ray micro-beams.

10. The method of claim 9 , wherein the x-ray inactive areas transmit x-rays, and the x-ray pixel array detector system additionally comprises a second x-ray detector positioned to detect the x-rays transmitted through the first x-ray detector.

11. The method of claim 1 , wherein the period of the periodic array of x-ray micro-beams at the object is less than 50 micrometers.

12. The method of claim 1 , wherein the length of each x-ray micro-beam along said axis at the object is greater than 1 millimeter.

13. The method of claim 1 , additionally comprising:
laterally displacing relative positions of the object and the periodic array of x-ray micro-beams in at least one direction perpendicular to the axis of one of the x-ray micro-beams by one or more times;
recording signals produced by said x-ray pixel array detector system after each lateral displacement has occurred; and
generating a two-dimensional image using said recorded signals.

14. The method of claim 13 , wherein laterally displacing the relative positions of the object and the periodic array of x-ray micro-beams is carried out by laterally displacing the object.

15. The method of claim 1 , additionally comprising:
changing a relative angular orientation of the object and the periodic array of x-ray micro-beams one or more times by an angle of 0.5 degrees or more;
recording signals produced by said x-ray pixel array detector system after each change of the relative angular orientation has occurred; and
generating a three-dimensional image using said recorded signals.

16. The method of claim 15 , wherein changing the relative angular orientation of the object and the periodic array of x-ray micro-beams is carried out by rotating the object.

17. The method of claim 1 , wherein said contrast is greater than 20%.

18. The method of claim 1 , wherein the common x-ray source comprises an array of x-ray generating microstructures.

19. An x-ray microscope system comprising:
a source of a periodic array of x-ray beams configured to impinge at least a portion of an object to be examined;
at least one x-ray pixel array detector comprising a plurality of pixels positioned to detect x-rays resulting from an interaction of said periodic array of x-ray beams with said object, the at least one x-ray pixel array detector producing at least one signal corresponding to said detected x-rays, and with said at least one x-ray pixel array detector aligned such that the x-rays detected by any single pixel of the plurality of pixels correspond to only one of the x-ray beams from among the periodic array of x-ray beams.

20. The x-ray microscope system of claim 19 , wherein the source further comprises at least one x-ray filter configured to limit the bandwidth of the x-rays.

21. The x-ray microscope system of claim 20 , wherein the at least one x-ray filter produces an x-ray spectrum having an average energy E 0 and an energy bandwidth within E 0 ±15%.

22. The x-ray microscope system of claim 19 , wherein the source comprises a grating structure to generate a Talbot interference pattern; and wherein the periodic array of x-ray beams corresponds to x-ray anti-nodes of the Talbot interference pattern and has a contrast between the Talbot anti-nodes and the neighboring Talbot nodes is greater than 10%.

23. The x-ray microscope system of claim 22 , wherein the object to be examined and the pixels of the x-ray pixel array detector are both positioned within a depth-of-focus of the Talbot interference pattern.

24. The x-ray microscope system of claim 22 , further comprising a mount configured to translate said object in two orthogonal directions.

25. The x-ray microscope system of claim 22 , wherein the grating structure to generate a Talbot interference pattern comprises one or more of: an absorption grating, a π/2 phase shifting grating, an phase shifting grating, a 1-D array of grating structures, a 2-D array of grating structures, a grid structure, and a checkerboard phase grating structure.

26. The x-ray microscope system of claim 22 , wherein the dimensions of the grating structure are selected such that the period of the period of the Talbot interference pattern is less than 50 micrometers.

27. The x-ray microscope system of claim 19 , additionally comprising a mask positioned to block a predetermined number of the x-ray beams.

28. The x-ray microscope system of claim 19 , wherein

Assignees

• Sigray Inc

Inventors

• Yun Wenbing
• Lewis Sylvia Jia Yun
• Kirz Janos
• Seshadri Srivatsan
• Lyon Alan Francis
• Vine David

Classifications

• A61B6/4291

  the detector being combined with a grid or grating · CPC title

• G01N23/201

  by measuring small-angle scattering · CPC title

• G01N23/20075

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

• G01N2223/3306

  object rotates · CPC title

• G21K7/00

  Gamma- or X-ray microscopes · CPC title