X-ray transmission spectrometer system

Patent metadata

Field	Value
Publication number	US-10295485-B2
Application number	US-201715663831-A
Country	US
Kind code	B2
Filing date	Jul 31, 2017
Priority date	Dec 5, 2013
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

An x-ray transmission spectrometer system to be used with a compact x-ray source to measure x-ray absorption with both high spatial and high spectral resolution. The spectrometer system comprises a compact high brightness x-ray source, an optical system with a low pass spectral filter property to focus the x-rays through an object to be examined, and a spectrometer comprising a crystal analyzer (and, in some embodiments, a mosaic crystal) to disperse the transmitted beam, and in some instances an array detector. The high brightness/high flux x-ray source may have a take-off angle between 0 and 15 degrees, and be coupled to an optical system that collects and focuses the high flux x-rays to micron-scale spots, leading to high flux density. The x-ray optical system may also act as a “low-pass” filter, allowing a predetermined bandwidth of x-rays to be observed at one time while excluding the higher harmonics.

First claim

We claim:

1. A method for x-ray absorption spectroscopy by an x-ray optical system, comprising:
collecting x-rays received from a first x-ray source through an x-ray optical system, the x-ray optical system having low-pass spectral filter properties such that x-rays above a cut-off energy are reduced;
producing a focused x-ray beam by the x-ray optical system with a focus at a predetermined focal plane downstream of the x-ray optical system, the focused x-ray beam passing through a sample to be analyzed,
the focused x-ray beam acting as a secondary source of diverging x-rays located at the focal plane; and
receiving the diverging x-rays from the secondary source by an x-ray spectrometer having an x-ray wavelength dispersive element and an analyzer to analyze the spectrum of the dispersed x-rays.

2. The method of claim 1 , wherein an aperture is placed at the focal plane and positioned to the said focused x-ray beam.

3. The method of claim 1 , wherein the x-ray optical system comprises at least a reflective x-ray focusing optic.

4. The method of claim 3 , wherein the reflective x-ray focusing optic has a predetermined high energy cutoff such that the x-ray reflectivity is less than 25% for x-rays with energies above 1.2 times a predetermined cutoff energy.

5. The method of claim 3 , wherein at least a portion of a reflective surface of the reflective x-ray focusing optic is axially symmetric.

6. The method of claim 1 , wherein the x-ray spectrometer comprises an array detector to record the x-rays dispersed by the x-ray wavelength dispersive element.

7. The method of claim 1 , wherein the spectrometer is a Rowland circle geometry spectrometer.

8. The method of claim 1 , wherein the spectrometer is a von Hamos spectrometer.

9. An x-ray absorption spectrometry system, comprising:
an x-ray source;
an x-ray optical system that receives x-rays from the x-ray source, includes a spectral filter property that reduces x-rays above a cut-off energy, and focuses the x-rays below the cut-off energy to a predetermined focal plane;
a mount for receiving a sample and positioning the sample in a path of the focused x-ray beam;
an aperture placed at the focal plane and centered with the focused x-ray beam in at least in one direction; and
a x-ray spectrometer that receives the x-rays that pass through the aperture and analyzes the received x-rays.

10. The system of claim 9 , wherein the focused x-ray beam has at least one dimension less than 30 micrometers.

11. The system of claim 9 , wherein the x-ray optical system comprises at least a reflective x-ray mirror focusing optic with a surface, wherein a portion of the surface is cylindrically symmetric.

12. The system of claim 9 , wherein the x-ray optical system comprises a reflective x-ray mirror focusing optic having a reflecting mirror surface, wherein a portion of the reflecting mirror surface has a quadric profile.

13. The system of claim 9 , additionally comprising a beam stop to block a portion of the x-rays that are not focused by the x-ray optic.

14. The system of claim 9 , wherein the x-ray spectrometer comprises an array detector.

15. The system of claim 9 , wherein the x-ray spectrometer comprises a wavelength dispersive element comprising at least one crystal analyzer.

16. The system of claim 15 , wherein the crystal analyzer comprises a single crystal.

17. The system of claim 15 , wherein the crystal analyzer is curved with a predetermined radius.

18. The system of claim 15 , wherein the crystal analyzer comprises a mosaic crystal.

19. The system of claim 15 , wherein the x-ray spectrometer comprises a mechanism to rotate the x-ray wavelength dispersive element.

20. The system of claim 15 , wherein the x-ray spectrometer includes a plurality of crystals, each of the crystals selected based on monochromaticity requirement.

21. The system of claim 9 , wherein the mount receives one or more of a plurality of samples and positions at least one sample in the focused x-ray beam for analysis.

22. The system of claim 9 further comprising at least one x-ray shielding component that prevents x-rays not-dispersed by the wavelength dispersive component from arriving at the detector.

Assignees

• Sigray Inc

Inventors

• Yun Wenbing
• Seshadri Srivatsan
• Kirz Janos
• Lewis Sylvia Jia Yun

Classifications

• G21K2201/064

  having a curved surface · CPC title

• G01N23/2076 Primary

  for spectrometry, i.e. using an analysing crystal, e.g. for measuring X-ray fluorescence spectrum of a sample with wavelength-dispersion, i.e. WDXFS · CPC title

• G01N23/223

  by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence · CPC title

• G01N23/087

  using polyenergetic X-rays · CPC title

• H01J2235/086

  Target geometry · CPC title