Detector for X-rays with high spatial and high spectral resolution

Patent metadata

Field	Value
Publication number	US-10295486-B2
Application number	US-201615240972-A
Country	US
Kind code	B2
Filing date	Aug 18, 2016
Priority date	Aug 18, 2015
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

An x-ray spectrometer system comprising an x-ray imaging system with at least one achromatic imaging x-ray optic and an x-ray detection system. The optical train of the imaging system is arranged so that its object focal plane partially overlaps an x-ray emitting volume of an object. An image of a portion of the object is formed with a predetermined image magnification at the x-ray detection system. The x-ray detection system has both high spatial and spectral resolution, and converts the detected x-rays to electronic signals. In some embodiments, the detector system may have a small aperture placed in the image plane, and use a silicon drift detector to collect x-rays passing through the aperture. In other embodiments, the detector system has an energy resolving pixel array x-ray detector. In other embodiments, wavelength dispersive elements may be used in either the optical train or the detector system.

First claim

We claim:

1. An x-ray spectrometer system, comprising:
an x-ray imaging system having an object plane and an image plane, said x-ray imaging system comprising at least one achromatic x-ray optical element having an optical axis and an x-ray reflective surface, at least a portion of the x-ray reflective surface shaped in the form of a portion of a quadric surface, said x-ray imaging system positioned to collect fluorescence x-rays emitted from a portion of an object such that the object plane overlaps with a predetermined x-ray emitting volume and to form a fluorescence x-ray image of the collected fluorescence x-rays in the image plane; and
an x-ray detector system configured to detect x-rays of at least one predetermined spatially distinct sub-portion of the fluorescence x-ray image corresponding to a predetermined volume within the x-ray emitting volume of the object and to produce electronic signals that are related to the number of x-rays having specific energy values detected for said predetermined spatially distinct sub-portion of the fluorescence x-ray image, the x-ray detector system comprising at least one aperture configured to transmit x-rays corresponding to the predetermined spatially distinct sub-portion of the fluorescence x-ray image while attenuating other x-rays, the at least one aperture configured to be controllably moved relative to the at least one achromatic x-ray optical element.

2. The x-ray spectrometer system of claim 1 , wherein the at least one aperture is positioned to be at the image plane.

3. The x-ray spectrometer system of claim 1 , wherein the x-ray detector system comprises an x-ray detector element.

4. The x-ray spectrometer system of claim 3 , wherein the x-ray detector element is selected from the group consisting of: a silicon drift detector, a Si(Li) detector, a Ge(Li) detector, and a PIN-diode.

5. The x-ray spectrometer system of claim 1 , wherein the x-ray detector system comprises an energy resolving pixel array detector.

6. The x-ray spectrometer system of claim 1 , wherein the x-ray imaging system has a point spread function with a full-width half maximum value greater than or equal to 0.1 micrometer and less than 20 micrometers.

7. The x-ray spectrometer system of claim 1 , wherein the x-ray imaging system has a magnification greater than or equal to 1 and less than or equal to 20.

8. The x-ray spectrometer system of claim 1 , in which the quadric surface is selected from the group consisting of: a spheroid, an ellipsoid, a paraboloid, a hyperboloid, an elliptic cylinder, a circular cylinder, an elliptic cone, and a circular cone.

9. The x-ray spectrometer system of claim 1 , in which the quadric surface has a reflecting surface layer comprising a material selected from the group consisting of: boron carbide, silicon dioxide, silicon nitride, quartz, glass, chromium, copper, nickel, rhodium, palladium, gold, nickel, iridium, and platinum.

10. The x-ray spectrometer system of claim 1 , in which the quadric surface has a reflecting surface comprising multilayers of pairs of materials, said pairs of materials selected from the group of material pairs consisting of: tungsten/carbon (W/C), tungsten/silicon (W/Si), tungsten/tungsten silicide (W/WSi 2 ), molybdenum/silicon (Mo/Si), nickel/carbon (Ni/C), chromium/scandium (Cr/Sc), lanthanum/boron carbide (La/B 4 C), and tantalum/silicon (Ta/Si).

11. The x-ray spectrometer system of claim 6 , in which the x-ray transmission efficiency for the x-ray imaging system is greater than 50%.

12. The x-ray spectrometer system of claim 1 , wherein the x-ray detector system additionally comprises:
at least one wavelength dispersive element to diffract the x-rays that have been transmitted through the at least one aperture; and
an x-ray detector to detect the intensity of the diffracted x-rays.

13. The x-ray spectrometer system of claim 12 , wherein the at least one wavelength dispersive element diffracts x-rays in different directions depending on their energy, and said x-ray detector is a position sensitive x-ray detector that detects the intensity of the x-rays diffracted at different directions by the at least one wavelength dispersive element.

14. The x-ray spectrometer system of claim 1 , wherein the at least one aperture is configured to be controllably moved among different positions within the image plane of the at least one achromatic x-ray optical element.

15. The x-ray spectrometer system of claim 1 , wherein the at least one aperture is configured to be controllably moved orthogonal to the optical axis of the at least one achromatic x-ray optical element.

16. The x-ray spectrometer system of claim 1 , wherein the at least one aperture is configured to be controllably moved along the optical axis of the at least one achromatic x-ray optical element.

17. The x-ray spectrometer system of claim 1 , wherein the at least one aperture is configured to be controllably moved relative to the at least one achromatic x-ray optical element for spatial mapping of different sub-volumes within the x-ray emitting volume.

18. The x-ray spectrometer system of claim 1 , wherein the at least one achromatic x-ray optical element comprises an axially symmetric optic and the x-ray reflective surface comprises an inner surface of the axially symmetric optic.

19. An x-ray spectroscopy system, comprising:
an x-ray source comprising:
a vacuum chamber;
a window transparent to x-rays attached to the wall of the vacuum chamber;
at least one electron beam emitter within the vacuum chamber; and
an anode target within the vacuum chamber, the anode target comprising:
a substrate comprising a first selected material, and
a planar first surface, from which thickness is measured in a direction perpendicular to the first planar surface, and two orthogonal lateral dimensions are measured parallel to the first planar surface; and
a plurality of discrete structures embedded into the first planar surface of the substrate such that each of the plurality of discrete structures is in thermal contact with the substrate, the plurality of discrete structures comprising one or more materials selected for its x-ray generation properties in which at least two of the plurality of discrete structures are arranged on an axis parallel to the first planar surface of the substrate and passing through the first window, in which each of the discrete microstructures has a thickness of less than 20 microns, and a lateral dimension in the direction of the axis of less than 50 microns,

the at least one electron beam emitter configured to direct electrons onto the at least two arranged discrete structures such that x-rays are generated from each of the at least two arranged discrete structures and at least a portion of the generated x-rays propagating on the axis from each of the at least two arranged discrete structures is transmitted through the window;

a first optical train having an optical axis positioned to correspond to the axis on which the at least two discrete structures are arranged, the first optical train positioned to collect x-rays generated by the anode target and to produce an x-ray beam focused to a predefined position within an object;
an x-ray imaging system having an object plane and an image plane, said x-ray imaging system comprising at least one achromatic x-ray optical element, said x-ray imaging system positioned to collect x-rays emitted from a portion of an object such that the object plane overlaps with a predetermined x-ray emitting volume and to form an image of the collected x

Assignees

• Sigray Inc

Inventors

• Yun Wenbing
• Lewis Sylvia Jia Yun
• Kirz Janos
• Stripe Benjamin Donald

Classifications

• G01N23/04

  and forming images of the material · CPC title

• G01N2223/052

  reflection · CPC title

• G01N23/20058

  Measuring diffraction of electrons, e.g. low energy electron diffraction [LEED] method or reflection high energy electron diffraction [RHEED] method · CPC title

• G01N23/223 Primary

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

• G01N2223/076

  X-ray fluorescence · CPC title