X-ray sequential array wavelength dispersion spectrometer

Abstract

An apparatus is configured to receive X-rays propagating from an X-ray source. The apparatus includes first and second X-ray diffractors, and first and second X-ray detectors, the second X-ray diffractor downstream of the first X-ray diffractor. The first X-ray diffractometer is configured to receive X-rays, diffract a first spectral band of the X-rays to the first X-ray detector, and transmit at least 2% of the received X-rays to the second X-ray diffractometer. The second X-ray diffractor is configured to receive the transmitted X-rays from the first X-ray diffractor and to diffract a second spectral band of the X-rays to the second X-ray detector. The first X-ray detector is configured to measure a first spectrum of a first spectral band of X-rays, and the second X-ray detector is configured to measure a second spectrum of a second spectral band of X-rays.

Description

[0001] Priority claim

[0002] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 337,407, filed on May 2, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application generally relates to apparatus and methods for X-ray spectroscopy, examples of which include but are not limited to: X-ray absorption spectroscopy (XAS); X-ray emission spectroscopy (XES); X-ray fluorescence spectroscopy (XFS). Background Art

[0004] An X-ray wavelength dispersive spectrometer (WDS) typically comprises (i) a diffractor comprising a crystal or a synthetic multilayer, the diffractor being configured to disperse incident X-rays according to the following Bragg's law: 2*d*sin(θ)=n*λ, wherein d is the lattice spacing of the crystal or the interlayer spacing of the multilayer, θ is the Bragg angle (e.g., the angle between the incident X-ray and a lattice plane of the crystal or a layer of the multilayer), n is an integer, and λ is the wavelength of the X-ray that satisfies the Bragg's law for the values ​​of d and θ; and (ii) a detector configured to record the portion of the X-rays dispersed by the diffractor.

[0005] WDS generally provides significantly higher energy resolution than energy dispersive spectrometer (EDS) and is widely used for X-ray spectroscopy in scanning electron microscope (SEM) spectroscopy, electron microprobe analyzer (EMPA), particle induced x-ray emission (PIXE) spectroscopy, X-ray fluorescence (XRF) analysis, total external reflection x-ray fluorescence (TXRF) analysis, X-ray emission spectroscopy (XES) and X-ray absorption spectroscopy (XAS). For XRF measurements, EDS can collect X-rays over a large energy range and can measure many atomic elements simultaneously, while WDS can measure X-ray spectra sequentially, but has better energy resolution, better detection sensitivity, and reduced spectral interference than EDS. Summary of the invention

[0006] In certain embodiments, a device (e.g., a sequential array wavelength dispersive spectrometer) is configured to receive X-rays propagating from an X-ray source along an X-ray propagation direction. The device includes a plurality of X-ray diffractors along the X-ray propagation direction. The plurality of X-ray diffractors include at least a first X-ray diffractor and a second X-ray diffractor, the second X-ray diffractor being downstream of the first X-ray diffractor. The device also includes a plurality of X-ray detectors, which include at least a first X-ray detector and a second X-ray detector. The first X-ray diffractor is configured to receive X-rays, diffract a first spectral band of X-rays to the first X-ray detector, and transmit at least 2% of the received X-rays to the second X-ray diffractor. The second X-ray diffractor is configured to receive transmitted X-rays from the first X-ray diffractor and diffract a second spectral band of X-rays to the second X-ray detector. The first X-ray detector includes at least one first active element configured to measure a first spectrum of at least a portion of the first spectral band of X-rays, and the second X-ray detector includes at least one second active element configured to measure a second spectrum of at least a portion of the second spectral band of X-rays. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A and Figure 1BTwo example devices including a plurality of substantially planar X-ray diffractors and a plurality of X-ray detectors according to certain embodiments described herein are schematically illustrated.

[0008] Figure 1C and Figure 1D Other example X-ray collimators according to certain embodiments described herein are schematically illustrated.

[0009] Figure 2A Another example apparatus comprising a plurality of substantially planar X-ray diffractors and a plurality of X-ray detectors according to certain embodiments described herein is schematically illustrated.

[0010] Figure 2B Schematically illustrates apertures configured to produce effective small X-ray sources in the dispersion planes of multiple X-ray diffractors according to certain embodiments described herein.

[0011] Figure 3 An example apparatus comprising a plurality of curved X-ray diffractors and a plurality of X-ray detectors according to certain embodiments described herein is schematically illustrated.

[0012] Figure 4 An example apparatus comprising at least one substantially flat X-ray diffractor, at least one substantially curved X-ray diffractor, and a plurality of X-ray detectors according to certain embodiments described herein is schematically illustrated.

[0013] Figure 5 Another example apparatus comprising at least one substantially flat X-ray diffractor, at least one substantially curved X-ray diffractor, and a plurality of X-ray detectors according to certain embodiments described herein is schematically illustrated.

[0014] Figure 6 Another example apparatus comprising a plurality of curved X-ray diffractors and a plurality of X-ray detectors according to certain embodiments described herein is schematically illustrated. DETAILED DESCRIPTION

[0015] X-rays analyzed by conventional WDS are incident on a point on the diffractor along the X-ray propagation direction, and only those X-rays within a narrow energy bandwidth that satisfies the Bragg law are diffracted, while X-rays outside the narrow energy bandwidth are not used and are generally absorbed by the diffractor, resulting in the loss of spectral information contained in the absorbed X-rays. Therefore, conventional WDS used in many systems (e.g., SEM spectroscopy, EMPA, PIXE spectroscopy, XRF analysis, TXRF analysis, XES, and XAS) has limited analysis speed and throughput.

[0016] Certain embodiments described herein provide an X-ray sequential array wavelength dispersive spectrometer (SA-WDS), characterized by a plurality of crystals arranged sequentially from an X-ray source along the direction of X-ray propagation. The plurality of crystals includes at least one upstream crystal having an X-ray transmission greater than 2%, wherein at least some of the transmitted X-rays are diffracted by at least one downstream crystal. Certain embodiments described herein provide methods of using X-ray SA-WDS for X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), and / or X-ray fluorescence spectroscopy (XFS). In certain embodiments, the SA-WDS disclosed herein can be used to significantly accelerate data collection by multiplexing the data acquisition process, dividing different X-ray energies onto different X-ray detectors operating simultaneously. Certain embodiments described herein are configured to accelerate data collection compared to a single energy WDS instrument at a time, and can be used with other radiation sources (e.g., laser plasma; high gain harmonic generation (HGHG); astronomical X-ray spectroscopy).

[0017] Certain embodiments described herein provide an X-ray SA-WDS, comprising a plurality of X-ray diffractors (e.g., crystals and / or multilayers) sequentially positioned along the propagation direction of an X-ray beam extending from an X-ray (e.g., collimated X-rays; divergent X-ray) source (e.g., a longitudinal array of X-ray diffractors). At least one upstream X-ray diffractor of the plurality of X-ray diffractors is configured to receive X-rays from the X-ray source, diffract at least some of the received X-rays, and transmit at least 2% of the received X-rays to at least one downstream X-ray diffractor of the plurality of X-ray diffractors. At least one downstream X-ray diffractor is configured to diffract at least some of the transmitted X-rays received from at least one upstream X-ray diffractor. The X-rays diffracted by at least one upstream X-ray diffractor have a first energy, and the X-rays diffracted by at least one downstream X-ray diffractor have a second energy that differs from the first energy by at least 1 eV. The X-ray SA-WDS also includes: at least one first X-ray detector configured to receive X-rays diffracted by at least one upstream X-ray diffractor; and at least one second X-ray detector configured to receive X-rays diffracted by at least one downstream X-ray diffractor. The at least one first X-ray detector and the at least one second X-ray detector are configured to generate spectral measurements (e.g., with energy resolution) of the received X-rays (e.g., X-ray intensity distribution as a function of X-ray energy).

[0018] Figure 1A , Figure 1B , Figure 2A , Figure 3 , Figure 4 , Figure 5 and Figure 6Various example devices 10 (e.g., X-ray SA-WDS) according to certain embodiments described herein are schematically illustrated. The device 10 is configured to receive X-rays 22 from an X-ray source 5, and includes a plurality of X-ray diffractors 30 positioned (e.g., arranged sequentially) along an X-ray propagation direction 24 of the X-rays 22, and a plurality of X-ray detectors 40. The plurality of X-ray diffractors 30 includes at least a first X-ray diffractor 30a (e.g., an upstream X-ray diffractor) and a second X-ray diffractor 30b (e.g., a downstream X-ray diffractor), and the plurality of X-ray detectors 40 includes at least a first X-ray detector 40a and a second X-ray detector 40b. The first X-ray diffractor 30a is configured to receive the X-rays 22, diffract a first spectral band 22a of the X-rays 22 (e.g., a first portion of the X-rays 22 having a first energy range) to the first X-ray detector 40a, and transmit at least 2% (e.g., at least 5%) of the X-rays 22 to the second X-ray diffractor 30b. The second X-ray diffractor 30b is configured to receive the transmitted X-rays 22 from the first X-ray diffractor 30a and diffract a second spectral band 22b of the X-rays 22 (e.g., a second portion of the X-rays 22 having a second energy range) to a second X-ray detector 40b. The first X-ray detector 40a includes at least one first active element 42a configured to measure a first spectrum (e.g., generate a spectral measurement) of at least a portion of the first spectral band 22a of the X-rays 22, and the second X-ray detector 40b includes at least one second active element 42b configured to measure a second spectrum (e.g., generate a spectral measurement) of at least a portion of the second spectral band 22b of the X-rays 22. The first energy range and / or the second energy range may include energies from less than 2 eV to up to 500 eV.

[0019] In some embodiments, the X-ray source 5 is configured to generate X-rays 22 in response to the incidence of ionizing radiation (e.g., X-rays; charged particles; electrons; protons). For example, the X-ray source 5 may include a sample to be analyzed using the apparatus 10, wherein the sample is irradiated with ionizing radiation to generate X-rays 22 (e.g., a sample irradiated by a conventional laboratory source of electrons or X-rays, a synchrotron radiation source, or other X-ray source that emits broadband or multi-energy X-rays). In some embodiments, the X-ray source 5 is not a component of the apparatus 10, while in some other embodiments, the X-ray source 5 is a component of the apparatus 10.

[0020] In certain embodiments (see, for example, Figure 1A and Figure 1B), the plurality of X-ray diffractors 30 further include a third X-ray diffractor 30c, and the plurality of X-ray detectors 40 further include a third X-ray detector 40c. The second X-ray diffractor 30b is configured to transmit at least 2% (e.g., at least 5%) of the X-rays 22 received from the first X-ray diffractor 30a to the third X-ray diffractor 30c. The third X-ray diffractor 30c is configured to receive the transmitted X-rays 22 from the second X-ray diffractor 30b and diffract a third spectral band 22c of the X-rays 22 (e.g., a third portion of the X-rays 22 having a third energy range) to the third X-ray detector 40c. The third X-ray detector 40c includes at least one third active element 42c configured to measure a third spectrum (e.g., generate a spectral measurement) of at least a portion of the third spectral band 22c of the X-rays 22. Other numbers of X-ray diffractors 30 (eg, 2, 4, 5, 6, or more) and other numbers of X-ray detectors 40 (eg, 2, 4, 5, 6, or more) are also compatible with certain embodiments described herein.

[0021] In certain embodiments, Figure 1A and Figure 1B Schematically illustrated, the apparatus 10 further comprises an X-ray collimator 20 configured to receive X-rays 22 (e.g., from an X-ray source 5, such as a sample under analysis) and collimate at least some of the X-rays 22 (e.g., reduce the divergence angle of at least some of the X-rays 22 to less than 1 degree, less than 0.1 degree, or less than 0.01 degree). The first X-ray diffractor 30a is configured to receive the collimated X-rays 22 from the X-ray collimator 20.

[0022] In some embodiments, the X-ray 22 from the X-ray collimator 20 is incident on the first X-ray diffractor 30a at a first Bragg angle θ1, and the first spectral band 22a of the X-ray 22 diffracted by the first X-ray diffractor 30a to the first X-ray detector 40a has a first central X-ray energy E1 (e.g., corresponding to a first wavelength λ1 that satisfies the Bragg law for the first lattice / layer spacing d1 and the first Bragg angle θ1 for the first X-ray diffractor 30a). The X-ray 22 from the first X-ray diffractor 30a is incident on the second X-ray diffractor 30b at a second Bragg angle θ2, and the second spectral band 22b of the X-ray 22 diffracted by the second X-ray diffractor 30b to the second X-ray detector 40b has a second central X-ray energy E2 (e.g., corresponding to a second wavelength λ2 that satisfies the Bragg law for the second lattice / layer spacing d2 and the second Bragg angle θ2 for the second X-ray diffractor 30b). For example, in which the plurality of X-ray diffractors 30 include a third X-ray diffractor 30c Figure 1A and Figure 1BSchematically illustrated, the X-ray 22 from the second X-ray diffractor 30b is incident on the third X-ray diffractor 30c at a third Bragg angle θ3, and the third spectral band 22c of the X-ray 22 diffracted by the third X-ray diffractor 30c to the third X-ray detector 40c has a third central X-ray energy E3 (e.g., corresponding to a third wavelength λ3 satisfying the Bragg's law for the third lattice / layer spacing d3 and the third Bragg angle θ3 for the third X-ray diffractor 30c).

[0023] In certain embodiments, Figure 2A , Figure 3 , Figure 4 , Figure 5 and Figure 6 Schematically illustrated, the apparatus 10 does not include an X-ray collimator, and the apparatus 10 receives divergent X-rays 22 from an X-ray source 5. In some embodiments, the X-ray source 5 is small (e.g., less than 100 microns in width) in the dispersion plane of the plurality of X-ray diffractors 30, and the first X-ray diffractor 30a receives the X-rays 22 from the X-ray source 5. In certain other embodiments in which the X-ray source 5 is not small (e.g., an extended X-ray source 5), the apparatus 10 may include an aperture 50 (e.g., a slit; an aperture) having a width of less than 100 microns to produce an effectively small (e.g., narrow) X-ray source in the dispersion plane of the plurality of X-ray diffractors 30, such as Figure 2B Schematically illustrated.

[0024] X-ray Collimator

[0025] In some embodiments, the X-ray collimator 20 includes at least one mirror optic 26 having a functional surface, wherein at least a portion of the surface has a quadratic profile (e.g., a parabolic shape; a hyperbolic shape). Figure 1A and Figure 1B Schematically illustrated, the mirror optics 26 may include an axisymmetric parabolic mirror optic (e.g., a parabolic mirror lens), such as a glass capillary having an inner surface with a parabolic surface profile, the mirror optic having a focal point aligned with the X-ray source 5. The mirror optics 26 is configured to receive the X-rays 22 from the X-ray source 5 within a collection solid angle and reflect the X-rays 22 into a substantially collimated X-ray beam. For another example, the mirror optics 26 may include a Wolter optic having a hyperbolic segment and a parabolic segment, the hyperbolic segment and the parabolic segment being configured such that the focal point of the hyperbolic segment is aligned with the X-ray source 5, and the focal point of the parabolic segment is aligned with another focal point of the hyperbolic segment. In some embodiments, the X-ray collimator 20 is rotationally symmetric about the longitudinal axis and extends more than 15 degrees around the longitudinal axis.

[0026] Figure 1C and Figure 1DOther example X-ray collimators 20 according to certain embodiments described herein are schematically illustrated. In certain embodiments, as Figure 1C Schematically illustrated, the X-ray collimator 20 may include a polycapillary optical device or a plurality of nested mirror optical devices (e.g., nested parabolic mirror optical devices; parabolic mirror lenses coaxially nested in Walter optical devices), each polycapillary optical device or nested mirror optical device receives X-rays 22 from the X-ray source 5 within a corresponding collection solid angle and reflects the X-rays into a substantially collimated X-ray beam. In some embodiments, such as Figure 1D Schematically illustrated, the X-ray collimator 20 comprises at least one Soller slit configured to receive X-rays 22 from an X-ray source 5 (eg an extended X-ray source) and to limit an angular spread ψ of the X-rays 22 emitted from the at least one Soller slit.

[0027] In some embodiments, the X-ray collimator 20 includes a substrate (e.g., glass), and the inner surface of the X-ray collimator 20 is coated with at least one layer (e.g., having a thickness greater than 20 nanometers) having a higher mass density to increase the collection angle of X-rays from the X-ray source 5 and improve the throughput of the device 10. Example materials for the at least one layer include, but are not limited to, materials with higher atomic numbers (Z) (such as Ni, Rh, Pt, Ir, etc.) or compound materials (such as oxides, nitrides, or carbides). In some embodiments, the inner reflective surface of the X-ray collimator is coated with at least one multilayer of alternating materials, examples of which include, but are not limited to: W / Si; Mo / Si; W / C; Mo / C; W / B4C; etc. In some embodiments, in order to increase the collection angle of X-rays at a predetermined (e.g., central) energy and energy bandwidth, the at least one multilayer includes a laterally graded multilayer (e.g., the total thickness of each bilayer is constant, but varies along the length of the reflective surface) and / or a depth-graded multilayer (e.g., the total thickness of the bilayer can vary along the depth of the multilayer). The layer thickness of constant thickness, depth gradient, and laterally gradient multilayers can be configured to efficiently reflect X-rays having energy in a predetermined bandwidth while substantially reducing (e.g., not efficiently reflecting) X-rays having energy outside the predetermined bandwidth. For nested coaxial mirrors, the functional surfaces of the mirror optics can have coatings that are different from each other (e.g., the functional surface of the inner mirror optic has a Pt coating, while the functional surface of one or more outer mirror optics has a multilayer coating).

[0028] In some embodiments, the collimator optics 26 is configured to have a reflection critical angle that maximizes the reflected X-ray flux in a predetermined energy range and substantially reduces (e.g., does not efficiently reflect) X-rays with energy outside of a predetermined bandwidth and that would otherwise result in background signal contributions in the form of scattering or higher-order harmonics from crystal reflections. For example, the collimator optics 26 can be configured to have a high energy cutoff that is less than twice the maximum operating energy of the collimator optics. In some embodiments, in order to cover a wide operating energy range, the X-ray collimator 20 includes a plurality of collimators, each of which is optimized for a corresponding predetermined X-ray energy range. In some embodiments, the X-ray collimator 20 includes a substantially flat mirror configured to receive the X-rays 22 from the collimator optics 26, the substantially flat mirror being configured to reflect the X-rays 22 with a high energy cutoff.

[0029] X-ray diffractometer

[0030] In some embodiments, at least one X-ray diffractor 30 of the plurality of X-ray diffractors 30 comprises at least one crystalline material (e.g., single crystal type, mosaic crystal type, substantially flat, substantially curved, or bent), examples of which include, but are not limited to, graphite, highly oriented pyrolytic graphite (HOPG), highly annealed pyrolytic graphite (HAPG), diamond, quartz, LiF (e.g., LiF(111); LiF(200)), Si (e.g., Si(111); Si(220); Si(400)), and Ge (e.g., Ge(111); Ge(220); Ge(311)). In some embodiments, at least one X-ray diffractor 30 is of single crystal type (e.g., to provide higher energy resolution), at least one X-ray diffractor 30 is of mosaic crystal type (e.g., to provide lower energy resolution), and / or the plurality of X-ray diffractors 30 comprises both at least one single crystal type and at least one mosaic crystal type. In some embodiments, at least two X-ray diffractors 30 (e.g., each X-ray diffractor 30) include the same material and diffraction plane (e.g., reflection or Miller index) and are configured to diffract X-rays having an energy overlap of less than 10% (e.g., less than 2%; less than 0.1%) with each other. In some other embodiments, at least two X-ray diffractors 30 (e.g., each X-ray diffractor 30) include different materials and / or different diffraction planes (e.g., Miller index). In some embodiments, the X-ray 22 diffracted by the first X-ray diffractor 30a has a first energy, and the X-ray 22 diffracted by the second X-ray diffractor 30b has a second energy that differs from the first energy by at least 1eV (e.g., at least 2eV; at least 5eV; at least 15eV; at least 30eV).

[0031] Table 1 lists example crystal materials and diffraction planes and corresponding diffracted X-ray energy ranges according to certain embodiments described herein. In certain embodiments, at least one crystal material and diffraction plane (e.g., Miller index) is configured to provide an optimal compromise between throughput and spectral resolution. In certain embodiments, the diffraction plane (e.g., Miller index) is configured to reduce (e.g., minimize; eliminate) background contributions caused by high-order reflections of high-energy X-rays. The presence of these higher-energy X-rays in the polychromatic X-rays 22 incident on the X-ray diffractor 30 may depend on the selection and design of the X-ray collimator 20.

[0032] Table 1:

[0033]

[0034] At least one X-ray diffractor 30 (e.g., the most upstream X-ray diffractor 30) may have an X-ray transmittance greater than 2% (e.g., greater than 5%). At least one X-ray diffractor 30 may be thin enough to provide X-ray transmittance. For example, at least one X-ray diffractor 30 may have a thickness (e.g., in the direction of propagation of X-rays 22 received by the X-ray diffractor 30) of less than 500 microns (e.g., less than 200 microns; less than 100 microns; less than 50 microns; less than 20 microns; less than 10 microns; less than 5 microns). At least one crystalline material may be held by a support structure configured to provide mechanical strength while not affecting the X-ray transmission of the X-ray diffractor 30. The thickness of at least one X-ray diffractor 30 may be selected to provide an optimal compromise between diffraction efficiency and transmission (e.g., to increase or maximize throughput). For example, the thickness of at least one crystalline material can vary between about 1.5 and 5 times the primary extinction thickness of X-rays in the crystalline material (e.g., for a primary extinction thickness of 2.5 microns, the thickness of the crystalline material can be in the range of about 3.5 microns to 12.5 microns). The diffraction efficiency can be in the range of about 37% to about 99% of the maximum theoretical diffraction efficiency, and the X-ray transmission can be greater than 2% (e.g., in the range of 2% to 95%).

[0035] In some embodiments, the X-ray diffractor 30 is cut asymmetrically to increase the energy bandwidth for diffracting X-rays 22 at a higher flux, or to reduce the energy bandwidth for a higher energy resolution. In some embodiments, at least one X-ray diffractor 30 diffracts X-rays 22 with different energies on a crystal surface (e.g., an imperfect crystal), and the corresponding X-ray detector 40 includes a pixel array detector to record the diffracted X-rays 22 in response to different positions on the X-ray diffractor 30. In some embodiments, the diffraction plane of at least one X-ray diffractor 30 is approximately parallel to the crystal surface of at least one X-ray diffractor 30, while in some other embodiments, the diffraction plane of at least one X-ray diffractor 30 is not approximately parallel to the crystal surface of at least one X-ray diffractor 30.

[0036] In some embodiments, at least one X-ray diffractor 30 in the plurality of X-ray diffractors 30 is substantially flat (see, e.g., Figure 1A , Figure 1B , Figure 2A , Figure 4 and Figure 5 ), while in certain other embodiments, at least one X-ray diffractometer 30 is curved in one direction or in two directions (e.g., spherically curved; cylindrically curved) (e.g., see Figure 3 , Figure 4 , Figure 5 and Figure 6 ).

[0037] In certain embodiments, at least one X-ray diffractor 30 in the plurality of X-ray diffractors 30 includes multiple layers.

[0038] The plurality of X-ray diffractors 30 may include at least one single crystal, at least one mosaic crystal, and / or at least one multilayer. For example, symmetric single crystals, asymmetric single crystals, mosaic crystals, and multilayers may be mixed and matched to provide a predetermined energy resolution and throughput.

[0039] In some embodiments, at least one X-ray diffractor 30 (e.g., each X-ray diffractor 30) of the plurality of X-ray diffractors 30 is configured to diffract X-rays 22 having a predetermined energy (e.g., a characteristic X-ray energy or X-ray line corresponding to one or more atomic elements of interest; a background contribution energy near the characteristic X-ray energy or X-ray line). In some embodiments, at least one X-ray diffractor 30 (e.g., each X-ray diffractor 30) is configured to diffract X-rays 22 with an energy resolution better than 50 eV (e.g., better than 25 eV; better than 10 eV; better than 5 eV; better than 2 eV; better than 1 eV) and / or within a spectral bandwidth greater than 10 eV (e.g., greater than 25 eV; greater than 50 eV; greater than 100 eV; greater than 200 eV; greater than 1 keV). The spectral bandwidth of the X-ray diffractor 30 may include one or more characteristic X-ray energies or X-ray lines corresponding to one or more atomic elements of interest, an energy of background contribution near the characteristic X-ray energy or X-ray line, or no X-ray line. In certain embodiments, at least one X-ray diffractor 30 (e.g., the most downstream X-ray diffractor 30) has a larger spectral bandwidth (e.g., a coarser energy resolution) than at least one other X-ray diffractor 30 (e.g., the most upstream X-ray diffractor 30). In certain embodiments, the spectral overlap of the X-rays 22 diffracted by at least two X-ray diffractors 30 is less than 50% (e.g., less than 25%; less than 10%; less than 5%; no spectral overlap). In certain other embodiments, the spectral overlap of the X-rays 22 diffracted by at least two X-ray diffractors 30 is greater than 5% (e.g., greater than 10%; greater than 25%). The diffraction energy, energy bandwidth, and spectral overlap of the X-ray diffractors 30 can be selected based on the specific spectral measurement to be performed.

[0040] In some embodiments, each of the plurality of X-ray diffractors 30 has substantially the same energy resolution as one another. In some other embodiments, the most upstream X-ray diffractor 30 (e.g., the first X-ray diffractor 30a) has the highest energy resolution of all the X-ray diffractors 30 (e.g., to be able to analyze fine features in the edge of the absorption spectrum of a sample such as TiO2 or rutile), while at least one other X-ray diffractor 30 either has substantially the same energy resolution as one another or has substantially different energy resolutions from one another.

[0041] In certain embodiments, the most upstream X-ray diffractor 30 (e.g., the first X-ray diffractor 30a) is configured to diffract X-rays having the weakest intensity (e.g., signal) of the spectrum to be measured. For example, the most upstream X-ray diffractor 30 may be configured to diffract characteristic X-rays of trace atomic elements of the source 5 (e.g., the sample under analysis) having low signal intensity, while other X-ray diffractors 30 (e.g., the second X-ray diffractor 30b and / or the third X-ray diffractor 30c) may be configured to diffract characteristic X-rays of other atomic elements (e.g., a large amount of atomic elements; trace atomic elements) of the source 5 having stronger X-ray signals.

[0042] In some embodiments, the most downstream X-ray diffractor 30 (e.g. Figure 1A and Figure 1B A third X-ray diffractor 30c; Figure 2A , Figure 3 , Figure 4 , Figure 5 and Figure 6 The second X-ray diffractor 30b) is substantially opaque to the X-rays 22. In some embodiments, the most downstream X-ray diffractor 30 has a larger spectral bandwidth than at least one other X-ray diffractor 30 (e.g., each other X-ray diffractor 30) in the plurality of X-ray diffractors 30 to increase the detected X-ray signal. For example, the most downstream X-ray diffractor 30 may include multiple layers, while at least one other X-ray diffractor 30 includes a thin crystalline material.

[0043] Sports Table

[0044] In certain embodiments, the apparatus 10 further includes at least one motion stage configured to move at least one X-ray diffractor 30 (e.g., each X-ray diffractor 30) of the plurality of X-ray diffractors 30 to adjust the incident angle of the X-ray 22 to the at least one X-ray diffractor 30. For example, a first motion stage (e.g., a rotary motion stage; a linear motion stage) may be configured to move the first X-ray diffractor 30a relative to the X-ray propagation direction 24 (e.g., to adjust the first Bragg angle θ1), a second motion stage (e.g., a rotary motion stage; a linear motion stage) may be configured to move the second X-ray diffractor 30b relative to the X-ray propagation direction 24 (e.g., to adjust the second Bragg angle θ2), and / or a third motion stage (e.g., a rotary motion stage; a linear motion stage) may be configured to move the third X-ray diffractor 30c relative to the X-ray propagation direction 24 (e.g., to adjust the third Bragg angle θ3). The movements of the first X-ray diffractor 30a, the second X-ray diffractor 30b, and the third X-ray diffractor 30c are Figure 1A and Figure 1B Indicated by a curved double arrow. Figure 1A and Figure 1B The example apparatus 10 includes at least one motion stage, and Figure 2A , Figure 3 , Figure 4 , Figure 5 and Figure 6 The example apparatus 10 may also include at least one motion stage. Figure 1A and Figure 1B An example apparatus 10 is schematically illustrated in which each X-ray diffractor 30 is moved by at least one motion stage, but in certain other embodiments, at least one X-ray diffractor 30 is fixed relative to the X-ray propagation direction 24 .

[0045] In some embodiments, at least one motion stage is configured to change at least one Bragg angle (e.g., at least one of the first Bragg angle θ1, the second Bragg angle θ2, and the third Bragg angle θ3) of the corresponding at least one X-ray diffractor 30 within a predetermined angular range (e.g., an angular range of 0.1 degrees wide, 1 degree wide, 5 degrees wide, or 50 degrees wide). In some embodiments, at least some of the motion stages are configured to simultaneously change the Bragg angles of the corresponding X-ray diffractors 30 (e.g., change the same angular amount; change different angular amounts). In some embodiments, at least one motion stage is configured to keep at least two X-ray diffractors 30 at a predetermined angle relative to each other (e.g., the angle between the diffraction planes of the first X-ray diffractor 30a and the second X-ray diffractor 30b is greater than 0.1 mrad). In some other embodiments, at least one motion stage is configured to adjust (e.g., rotate) the angle of at least two X-ray diffractors 30 relative to each other and / or relative to the X-ray propagation direction 24. For example, the X-ray diffractors 30 can be rotated at the same angular speed (e.g., rotated at the same angular increment at the same time) or rotated at different angular speeds (e.g., rotated at different angular increments at the same time). In some embodiments, at least one X-ray diffractor 30 is configured to rotate while the corresponding X-ray detector 40 remains fixed, while in some other embodiments, at least one X-ray diffractor 30 and the corresponding X-ray detector 40 are configured to move in tandem with each other (e.g., the X-ray detector 40 moves according to the rotation of the X-ray diffractor 30 to ensure detection of the diffraction spectral band of the X-rays).

[0046] By changing at least one Bragg angle of the corresponding at least one X-ray diffractor 30, the energy of the X-rays diffracted by the X-ray diffractor 30 to the corresponding X-ray detector 40 is changed. In some embodiments, during the spectral measurement, each X-ray diffractor 30 remains stationary and is configured (e.g., optimized) to diffract a predetermined X-ray energy or to diffract over a predetermined spectral bandwidth (e.g., each X-ray diffractor 30 is configured to diffract one or more corresponding characteristic X-ray lines of one or more corresponding atomic elements), thereby providing simultaneous measurement of multiple characteristic X-ray lines (e.g., of multiple atomic elements). In some other embodiments, during the spectral measurement, at least one X-ray diffractor 30 remains stationary and is configured to diffract a predetermined X-ray energy, while at least one other Bragg angle of at least one other X-ray diffractor 30 is changed to diffract X-rays having other predetermined discrete X-ray energies or having a predetermined X-ray energy range (e.g., to cover other predetermined spectral bandwidths).

[0047] X-ray detectors

[0048] Examples of X-ray detectors 40 compatible with certain embodiments described herein include, but are not limited to: ionization chambers; proportional counters; scintillation counters; PIN diodes; silicon drift detectors (SDDs); pixels of pixel array detectors (e.g., charge coupled device (CCD) detectors; complementary metal oxide semiconductor (CMOS) detectors; photon counting detectors). In certain embodiments, the plurality of X-ray detectors 40 include at least one X-ray detector 40 having an energy resolution better than 25% (e.g., 5%) of the energy of the detected X-rays.

[0049] In some embodiments, at least one of the plurality of X-ray detectors 40 includes a pixel array detector extending in at least one dimension and is used with a corresponding X-ray diffractor 30 including at least one crystalline material in which the X-ray diffractor 30 is not substantially flat (e.g., warped). At least one X-ray detector 40 may be pixelated (e.g., including pixels having a pixel size in the range of 3 microns to 200 microns in the dispersion direction and in the range of 3 microns to 5000 microns in the sagittal direction) or may include a strip detector or a two-dimensional detector. At least one X-ray detector 40 may include a direct conversion solid-state X-ray detector (e.g., a pixelated photon counting detector; a CCD detector; a CMOS detector). At least one X-ray detector 40 may include a plurality of SDD detectors stacked on top of each other.

[0050] In some embodiments, at least one of the plurality of X-ray detectors 40 includes a photon counting pixel array detector having at least one energy threshold configured to reject X-rays having energies below the at least one energy threshold (e.g., remove detection) and / or reject X-rays having energies above the at least one energy threshold (e.g., remove detection). For example, the X-ray detector 40 may be configured to reject higher harmonics (e.g., multiples) or lower harmonics (e.g., multiples) of the energy of the measurement recorded by the X-ray detector 40. For example, the photon counting pixel array detector may have at least two energy thresholds configured to define an energy window (e.g., an energy window having a width of at least 1 keV) between the two energy thresholds, such that X-rays below and above the energy window are not detected. The energy thresholds may be preset to a few keV (e.g., in the range of 3 keV to 8 keV; in the range of 1 keV to 3 keV) or sub-keV (e.g., SDD with an energy window on the order of 100 eV to 250 eV).

[0051] By reducing (e.g., eliminating) higher order harmonics, certain embodiments can reduce (e.g., eliminate) background contributions in the absorption spectrum, thereby significantly increasing the throughput of the device 10. For example, eliminating 10% of the background contribution caused by higher order harmonics in the spectrum can increase the throughput of the device 10 by approximately 3 times for XAS measurements. Eliminating higher energy X-rays can also allow the ionizing radiation source (e.g., to generate X-rays in the X-ray source 5) to operate at a higher flux (e.g., a higher voltage) in order to achieve a higher throughput.

[0052] In certain embodiments where at least one X-ray detector 40 comprises a pixelated detector, the pixelated detector may comprise a one-dimensional or two-dimensional array of pixels. The pixelated detector may have a long dimension in the range of 30 mm to 50 mm, in the range of 30 mm to 100 mm, in the range of 100 mm to 300 mm, or in the range of 300 mm or more. For a one-dimensional array of pixels, the detector may be oriented such that the long dimension of the array is along the scattering plane. The pixel size may be large enough (e.g., on the order of 0.5 mm to 10 mm) to receive a diffracted X-ray beam in the scattering plane. In a sagittal plane (e.g., approximately perpendicular to the scattering plane), the diffracted X-ray beam may be detected by a plurality of pixels, each pixel being independent of adjacent pixels and configured to detect a corresponding portion of the diffracted X-ray beam. For a two-dimensional array detector, the detector may be used to record diffracted X-rays from different regions of the corresponding X-ray diffractor 30 (e.g., different regions of a substantially flat crystal having a crystal plane that varies across the crystal), which may allow for simultaneous detection of a range of X-ray energies.

[0053] In some embodiments, the apparatus 10 further includes at least one motion stage configured to move at least one X-ray detector 40 (e.g., each X-ray detector 40) among the plurality of X-ray detectors 40 so that the diffracted X-rays from the corresponding X-ray diffractor 30 are received by the X-ray detector 40. For example, a first motion stage (e.g., a rotary motion stage; a linear motion stage) may be configured to move the first X-ray detector 40a, a second motion stage (e.g., a rotary motion stage; a linear motion stage) may be configured to move the second X-ray detector 40b, and / or a third motion stage (e.g., a rotary motion stage; a linear motion stage) may be configured to move the third X-ray detector 40c.

[0054] In some embodiments, at least some of the motion stages are configured to simultaneously move the corresponding X-ray detectors 40. For example, the X-ray detectors 40 may move at the same linear or angular velocity or at different linear or angular velocities. In some embodiments, at least one X-ray detector 40 and the corresponding at least one X-ray diffractor 30 are configured to move in tandem with each other (e.g., the X-ray detector 40 moves according to the rotation of the X-ray diffractor 30 to ensure detection of the diffraction spectral band of the X-ray).

[0055] Example Device

[0056] Figure 1A and Figure 1B Two example devices 10 are schematically illustrated, including a plurality of substantially flat X-ray diffractors 30 and a plurality of X-ray detectors 40 according to some embodiments described herein. The X-ray diffractors 30 are configured to receive substantially collimated X-rays 22 and are positioned sequentially along the X-ray beam propagation direction 24. Figure 1A As shown, each X-ray diffractor 30 includes a substantially flat crystal, and each X-ray detector 40 includes at least one active element 42 configured to directly receive a diffraction spectral band of the X-rays 22 from the corresponding X-ray diffractor 30. Figure 1B As shown, the first X-ray diffractor 30a and the second X-ray diffractor 30b are substantially flat grooved crystals, and the third X-ray diffractor 30c is substantially flat crystal. Each of the at least one X-ray detector 40 includes at least one active element 42, and each of the first X-ray detector 40a and the second X-ray detector 40b includes at least one reflective X-ray optical device 44a, 44b (e.g., an X-ray mirror), the at least one reflective X-ray optical device 44a, 44b being configured to directly receive the diffraction spectral band of the X-ray 22 from the corresponding X-ray diffractor 30a, 30b, and reflect at least a portion of the diffraction spectral band of the X-ray 22 to the corresponding at least one active element 42a, 42b. In some embodiments, as Figure 1BAs shown, the third X-ray detector 40c does not include at least one reflective X-ray optical device, while in certain other embodiments, the third X-ray detector 40c includes at least one reflective X-ray optical device.

[0057] Figure 2A An example device 10 including a plurality of substantially flat X-ray diffractors 30 and a plurality of X-ray detectors 40 according to certain embodiments described herein is schematically illustrated. The X-ray diffractors 30 are configured to receive divergent X-rays 22 (e.g., from an X-ray source 5 extending less than 100 microns along a dispersion plane) and are positioned sequentially along an X-ray beam propagation direction 24. Each of the first X-ray detector 40a and the second X-ray detector 40b may include at least one active element 42a, 42b (e.g., a pixel array detector) and is configured to detect a corresponding diffraction spectral band of the X-rays 22 from the corresponding X-ray diffractors 30a, 30b. The angle between the diffraction planes of the two X-ray diffractors 30 may be greater than 0.1 mrad.

[0058] Figure 3 An example apparatus 10 is schematically illustrated that includes a plurality of curved (e.g., in at least one direction; spherically curved; cylindrically curved) X-ray diffractors 30 and a plurality of X-ray detectors 40 according to certain embodiments described herein. The X-ray diffractors 30 are configured to receive divergent X-rays 22 and are positioned sequentially along the X-ray beam propagation direction 24. The X-ray diffractors 30 include: a first X-ray diffractor 30a, which includes a first von Hamos crystal having a corresponding first longitudinal axis 32a; and a second X-ray diffractor 30b, which includes a second von Hamos crystal having a corresponding second longitudinal axis 32b at a non-zero angle Θ (e.g., greater than 0.1 mrad) relative to the first longitudinal axis 30a. In certain embodiments, the non-zero angle Θ is fixed to a predetermined value (e.g., in the range of 0.1 mrad to 0.5 radians) during spectral measurements, while in certain other embodiments, the non-zero angle Θ varies during spectral measurements. Although Figure 3 Two X-ray diffractors 30 each including a von Hammers crystal are shown, but some other embodiments may include additional X-ray diffractors 30 each including a von Hammers crystal. At least one X-ray detector 40 includes a pixel array detector configured to detect a diffraction spectral band of X-rays 22 diffracted by a corresponding X-ray diffractor 30 (e.g., a von Hammers crystal). In some embodiments, the von Hammers crystal of the most upstream X-ray diffractor 30 (e.g., the first X-ray diffractor 30a) has an X-ray transmittance of at least 2% (e.g., at least 5%), and the von Hammers crystal of the most downstream X-ray diffractor 30 (e.g., the second X-ray diffractor 30b) has an X-ray transmittance of less than 5% (e.g., less than 2%). Figure 3 The device 10 can be considered to include a first von Hamos WDS and one or more second von Hamos WDSs positioned sequentially downstream of the first von Hamos WDS, each second von Hamos WDS being configured to intercept at least a portion of the X-rays 22 transmitted through the first von Hamos WDS and any other upstream von Hamos WDS. In certain embodiments, at least one von Hamos WDS is configured to intercept the X-rays 22 that are intercepted and transmitted through at least one other von Hamos WDS (see, for example, Figure 3 ) of the X-rays 22, while in certain other embodiments, at least one von Hamos WDS is configured to intercept at least a portion of the X-rays that are not intercepted by at least one other von Hamos WDS.

[0059] Figure 4 An example apparatus 10 is schematically illustrated according to some embodiments described herein, including at least one substantially flat X-ray diffractor 30, at least one substantially curved (e.g., in at least one direction; spherically curved; cylindrically curved) X-ray diffractor 30, and a plurality of X-ray detectors 40. The X-ray diffractors 30 are configured to receive divergent X-rays 22 and are positioned sequentially along the X-ray beam propagation direction 24. Figure 4 As shown, the first X-ray diffractor 30a includes a substantially flat crystal having an X-ray transmittance of at least 2% (e.g., at least 5%), and the second X-ray diffractor 30b includes a von Hammers crystal located downstream of the first X-ray diffractor 30a. At least one X-ray detector 40 includes a pixel array detector configured to detect a diffraction spectral band of the X-rays 22 diffracted by the corresponding X-ray diffractor 30.

[0060] Figure 5 Another example apparatus 10 is schematically illustrated according to some embodiments described herein, including at least one substantially flat X-ray diffractor 30, at least one substantially curved (e.g., in at least one direction; spherically curved; cylindrically curved) X-ray diffractor 30, and a plurality of X-ray detectors 40. The X-ray diffractors 30 are configured to receive divergent X-rays 22 and are positioned sequentially along the X-ray beam propagation direction 24. Figure 5As shown, the first X-ray diffractor 30a includes a substantially flat crystal having an X-ray transmittance of at least 2% (e.g., at least 5%), and the second X-ray diffractor 30b includes a spherical or cylindrical curved crystal (e.g., a Johann crystal; a Johannsson crystal) located downstream of the first X-ray diffractor 30a. At least one X-ray detector 40 includes a pixel array detector configured to detect a diffraction spectral band of the X-rays 22 diffracted by the corresponding X-ray diffractor 30. In some embodiments, the X-ray source 5, the second X-ray diffractor 30b, and the second X-ray detector 40b (e.g., including a single active element 42b (e.g., a pixel; a detector element)) are configured as a Rowland circle geometry. In certain other embodiments, the X-ray source 5, the second X-ray diffractor 30b, and the second X-ray detector 40b are configured as a non-Roland circle geometry, wherein the X-ray source 5 is within the Rowland circle, while the second X-ray diffractor 30b and the second X-ray detector 40b are on the Rowland circle, and the second X-ray detector 40b includes a pixel array detector.

[0061] Figure 6 Another example apparatus 10 is schematically illustrated according to some embodiments described herein, including a plurality of curved (e.g., in at least one direction; spherically curved; cylindrically curved) X-ray diffractors 30 and a plurality of X-ray detectors 40. The X-ray diffractors 30 are configured to receive divergent X-rays 22 and are positioned sequentially along the X-ray beam propagation direction 24. Figure 6 As shown, the X-ray diffractor 30 includes: a first X-ray diffractor 30a, which includes a spherical or cylindrical curved first crystal (e.g., a John crystal; Johnson crystal) with an X-ray transmittance of at least 2% (e.g., at least 5%); and a second X-ray diffractor 30b, which includes a spherical or cylindrical curved first crystal (e.g., a John crystal; Johnson crystal) located downstream of the first X-ray diffractor 30a. At least one X-ray detector 40 includes a pixel array detector, which is configured to detect a diffraction spectral band of the X-ray 22 diffracted by the corresponding X-ray diffractor 30. In some embodiments, the X-ray source 5, the first X-ray diffractor 30a, and the first X-ray detector 40a are configured as a first Rowland circle geometry, while the X-ray source 5, the second X-ray diffractor 30b, and the second X-ray detector 40b are configured as a second Rowland circle geometry.

[0062] Example XAS, XES and XRF methods

[0063] In certain embodiments, the apparatus 10 is configured to perform X-ray absorption spectroscopy (XAS) and / or X-ray emission spectroscopy (XES) of various materials (e.g., catalysts in fuel cells; semiconductor quantum structures; magnetic semiconductor structures; nanotechnology; materials for energy storage and conversion). For example, XAS measurements can be performed by detecting X-ray absorption as a function of X-ray energy with sufficient energy resolution within the absorption limit of the atomic element (e.g., less than 2 eV or less than 1 eV for detecting X-ray absorption near edge structure (XANES) indicating chemical states such as oxidation states; less than 10 eV or less than 5 eV for detecting extended X-ray absorption fine structure (EXAFS) indicating interatomic distances and coordination numbers). For another example, XES measurements can be performed by detecting X-ray emission as a function of X-ray energy with sufficient energy resolution (e.g., less than 2 eV) to determine chemical states such as oxidation states.

[0064] In certain embodiments, the apparatus 10 is configured to perform X-ray fluorescence (XRF) spectroscopy in various applications (e.g., metallurgy, geology and mining, semiconductor metrology, failure analysis, electronics, archeology, and environmental analysis. For example, XRF measurements can be made by detecting the number of characteristic X-rays emitted by atomic elements in a material (e.g., solid; liquid; powder), and in many cases, XRF measurements are made non-destructively.

[0065] Conventional XAS, XES and / or XRF systems that use crystal-based spectrometers to provide adequate energy resolution are limited in throughput because only a narrow energy bandwidth of X-rays incident on the crystal at points that satisfy the Bragg law is reflected, while X-rays outside the narrow energy bandwidth are lost or wasted (e.g., absorbed by the crystal), resulting in a reduction in the signal contained in the absorbed X-rays. In contrast, using the apparatus 10 according to certain embodiments described herein can efficiently use a wider energy bandwidth of X-rays simultaneously and can increase data collection speed.

[0066] In certain embodiments, for XANES measurements, at least one X-ray diffractor 30 has an energy bandwidth better than 3 eV (e.g., better than 2 eV; better than 1 eV), but a maximum center energy difference of less than 50 eV (e.g., less than 20 eV; less than 10 eV). In certain embodiments, the difference between the average energies of different X-ray diffractors 30 is between 2 eV and 10 eV or up to 250 eV. To obtain XANES measurements within an energy range (e.g., 30 eV to 100 eV), the X-ray diffractors 30 can be rotated and the X-rays diffracted by each X-ray diffractor 30 can be recorded. The spectra recorded by all X-ray diffractor 30 / X-ray detector 40 pairs can be normalized to produce a single spectrum.

[0067] In some embodiments, for EXAFS measurements, at least one X-ray diffractor 30 has an energy spectral resolution better than 50 eV (e.g., better than 10 eV; better than 5 eV; better than 2 eV), and the center energies of the X-ray diffractors 30 differ by more than 1 eV (e.g., more than 2 eV; more than 5 eV; more than 10 eV), but the maximum center energy difference is less than 100 eV (e.g., less than 500 eV). In some embodiments, the difference between the center energies of different X-ray diffractors 30 is in the range of 5 eV to 50 eV. In order to obtain EXAFS measurements in an energy range (e.g., 400 eV to 1000 eV), the X-ray diffractors 30 can be rotated and the X-rays diffracted by each X-ray diffractor 30 can be recorded. The spectra recorded by all X-ray diffractor 30 / X-ray detector 40 pairs can be normalized to produce a single spectrum.

[0068] In some embodiments, for XES measurement, at least one X-ray diffractor 30 has an energy bandwidth better than 3 eV (e.g., better than 2 eV; better than 1 eV), and the center energies of the X-ray diffractors 30 differ by more than 1 eV (e.g., more than 2 eV; more than 3 eV; more than 10 eV), but the maximum center energy difference is less than 50 eV. In some embodiments, the difference between the center energies of different X-ray diffractors 30 is in the range of 2 eV to 50 eV (e.g., in the range of 2 eV to 10 eV). In some embodiments, different X-ray diffractors 30 are configured to measure different characteristic X-ray emission lines (e.g., Kα and Kβ X-ray lines). For example, at least one upstream X-ray diffractor 30 can be configured to diffract a first characteristic X-ray line with a lower fluorescence yield (e.g., a Kβ X-ray line or one of its satellite lines), and the X-ray diffractors 30 can be rotated and the X-rays diffracted by each X-ray diffractor 30 can be recorded. The spectra recorded by all X-ray diffractor 30 / X-ray detector 40 pairs may be normalized to produce a single spectrum.

[0069] In some embodiments, for XRF measurements, the device 10 can simultaneously and efficiently use X-rays with a wider energy bandwidth, and can increase the data collection speed. In some embodiments, the X-rays are generated by a primary X-ray beam or charged particles incident on the sample under analysis. In some embodiments, at least one X-ray diffractor 30 has an energy resolution better than 50eV (e.g., better than 25eV; better than 10eV). In some embodiments, the difference between the average energies of different X-ray diffractors 30 is greater than 10eV (e.g., greater than 25eV; greater than 50eV; greater than 500eV). In some embodiments, different X-ray diffractors 30 are configured to measure characteristic X-ray emission lines of different atomic elements (e.g., Ca and Cu X-ray lines). In some embodiments, at least one upstream X-ray diffractor 30 is configured to diffract characteristic X-rays of atomic elements with low concentrations or low fluorescence signals. In certain embodiments, at least one upstream X-ray diffractor 30 is configured to diffract characteristic X-rays of an atomic element of interest, and at least one additional X-ray diffractor 30 is configured to diffract X-rays with energies close to characteristic X-ray lines (e.g., to improve the accuracy of analysis of the atomic element). The X-ray diffractors 30 may be rotated, and the X-rays diffracted by each X-ray diffractor 30 may be recorded. The spectra recorded by all X-ray diffractor 30 / X-ray detector 40 pairs may be normalized to produce a measure of the atomic composition of the material.

[0070] Although for ease of understanding, common terms are used to describe the system and method of certain embodiments, these terms are used herein to have their broadest reasonable interpretation. Although various aspects of the present disclosure are described with respect to illustrative examples and embodiments, the disclosed examples and embodiments should not be interpreted as restrictive. Unless otherwise specifically stated, or otherwise understood in the context used, conditional language, such as "can", "may" or "can" is generally intended to convey that certain embodiments include certain features, elements and / or steps, while other embodiments do not include certain features, elements and / or steps. Thus, such conditional language is generally not intended to imply that features, elements and / or steps are necessary for one or more embodiments in any way. In particular, the terms "include" and "comprise" should be interpreted as referring to elements, parts or steps in a non-exclusive manner, indicating that the elements, parts or steps mentioned can exist, use or combine with other elements, parts or steps not explicitly mentioned.

[0071] Unless specifically stated otherwise, linking language, such as the phrase "at least one of X, Y, and Z," should be understood in the context generally used to convey that an item, term, etc. may be X, Y, or Z. Thus, such linking language is not generally intended to imply that certain embodiments require the presence of at least one X, at least one Y, and at least one Z.

[0072] As used herein, the degree language of terms such as "approximately", "about", "substantially" and "roughly" indicates a value, amount or characteristic close to the value, amount or characteristic, which still performs the desired function or achieves the desired result. For example, the terms "approximately", "about", "substantially" and "roughly" can refer to an amount within ±10%, within ±5%, within ±2%, within ±1% or within ±0.1% of the amount. As another example, the terms "substantially parallel" and "roughly parallel" refer to a value, amount or characteristic that deviates from completely parallel ±10 degrees, ±5 degrees, ±2 degrees, ±1 degrees or ±0.1 degrees, while the terms "substantially vertical" and "roughly vertical" refer to a value, amount or characteristic that deviates from completely vertical ±10 degrees, ±5 degrees, ±2 degrees, ±1 degrees or ±0.1 degrees. The scope disclosed herein also covers any and all overlaps, sub-ranges and combinations thereof. Languages ​​such as "up to", "at least", "greater than", "less than", "between...", etc. include the cited numbers. As used herein, the meaning of "a", "an", and "the" includes plural references unless the context clearly indicates otherwise. Although structures and / or methods are discussed herein in terms of elements marked by ordinal adjectives (e.g., first, second, etc.), ordinal adjectives are only used as labels to distinguish one element from another, and ordinal adjectives are not used to indicate the order of these elements or their use.

[0073] Various configurations have been described above. It should be understood that the embodiments disclosed herein are not mutually exclusive and can be combined with each other in various arrangements. Although the present invention has been described with reference to these specific configurations, these descriptions are intended to illustrate the present invention rather than being restrictive. Without departing from the true spirit and scope of the present invention, various modifications and applications can be imagined by those skilled in the art. Thus, for example, in any method or process disclosed herein, the actions or operations constituting the method / process can be performed in any suitable order and are not necessarily limited to any specific disclosed order. The features or elements from the various embodiments and examples discussed above can be combined with each other to produce alternative configurations compatible with the embodiments disclosed herein. Various aspects and advantages of the embodiments are described where appropriate. It should be understood that, according to any particular embodiment, all these aspects or advantages may not necessarily be achieved. Thus, for example, it should be recognized that various embodiments can be performed in a manner that realizes or optimizes an advantage or a group of advantages as taught herein, without having to realize other aspects or advantages as taught or suggested herein.

Claims

1. A device configured to receive X-rays propagating from an X-ray source along an X-ray propagation direction, the device comprising: a plurality of X-ray diffractors along the X-ray propagation direction, the plurality of X-ray diffractors comprising at least a first X-ray diffractor and a second X-ray diffractor, the second X-ray diffractor being downstream of the first X-ray diffractor; as well as a plurality of X-ray detectors, comprising at least a first X-ray detector and a second X-ray detector, the first X-ray diffractor being configured to receive the X-rays, diffract a first spectral band of the X-rays to the first X-ray detector, and transmit at least 2% of the received X-rays to the second X-ray diffractor, the second X-ray diffractor being configured to receive the transmitted X-rays from the first X-ray diffractor and to diffract a second spectral band of the X-rays to the second X-ray detector, The first X-ray detector includes at least one first active element configured to measure a first spectrum of at least a portion of the first spectral band of the X-rays, and the second X-ray detector includes at least one second active element configured to measure a second spectrum of at least a portion of the second spectral band of the X-rays.

2. The device according to claim 1, wherein: The plurality of X-ray diffractors are sequentially arranged along the X-ray propagation direction.

3. The device according to claim 1, wherein: The plurality of X-ray diffractors further include a third X-ray diffractor, and the plurality of X-ray detectors further include a third X-ray detector, the third X-ray diffractor being downstream of the second X-ray diffractor, the second X-ray diffractor being configured to transmit at least 2% of the X-rays received from the first X-ray diffractor to the third X-ray diffractor, the third X-ray diffractor being configured to receive the transmitted X-rays from the second X-ray diffractor and diffract a third spectral band of the X-rays to the third X-ray detector, the third X-ray detector including at least one third active element configured to measure a third spectrum of at least a portion of the third spectral band of the X-rays.

4. The apparatus according to claim 1, further comprising an X-ray collimator configured to receive the X-rays from the X-ray source and collimate at least some of the X-rays, and the first X-ray diffractor is configured to receive the collimated X-rays from the X-ray collimator.

5. The device according to claim 4, wherein: The X-ray collimator comprises at least one mirror optic having a functional surface, wherein at least a portion of the surface has a parabolic shape.

6. The device according to claim 4, wherein: The X-ray collimator includes a Walter optic having a hyperbolic segment and a parabolic segment configured such that a focus of the hyperbolic segment is aligned with the X-ray source and a focus of the parabolic segment is aligned with another focus of the hyperbolic segment.

7. The device according to claim 4, wherein: The X-ray collimator comprises a polycapillary optic or a plurality of nested mirror optics.

8. The device according to claim 4, wherein: The X-ray collimator comprises at least one Soller slit.

9. The device according to claim 4, wherein: The X-rays from the X-ray collimator are incident on the first X-ray diffractor at a first Bragg angle, and the first spectral band of the X-rays diffracted by the first X-ray diffractor to the first X-ray detector has a first central X-ray energy, the X-rays from the first X-ray diffractor are incident on the second X-ray diffractor at a second Bragg angle, and the second spectral band of the X-rays diffracted by the second X-ray diffractor to the second X-ray detector has a second central X-ray energy, and the second X-ray energy differs from the first X-ray energy by at least 1eV.

10. The device according to claim 9, wherein: The multiple X-ray diffractors also include a third X-ray diffractor, and the multiple X-ray detectors also include a third X-ray detector, the third X-ray diffractor is configured to diffract the third spectral band of the X-rays to the third X-ray detector, the third X-ray diffractor is downstream of the second X-ray diffractor, the X-rays from the second X-ray diffractor are incident on the third X-ray diffractor at a third Bragg angle θ3, and the third spectral band of the X-rays 22 diffracted by the third X-ray diffractor to the third X-ray detector has a third central X-ray energy E3.

11. The device according to claim 1, wherein: The X-rays received by the first X-ray diffractor are divergent.

12. The apparatus of claim 11, further comprising an aperture between the X-ray source and the first X-ray diffractor, the aperture having a width less than 100 microns in a dispersion plane of the first X-ray diffractor.

13. The device according to claim 1, wherein: At least one X-ray diffractor of the plurality of X-ray diffractors comprises at least one crystalline material.

14. The device according to claim 13, wherein: The at least one crystalline material is selected from the group consisting of graphite, highly oriented pyrolytic graphite (HOPG), highly annealed pyrolytic graphite (HAPG), diamond, quartz, LiF, Si, and Ge.

15. The device according to claim 13, wherein: At least one X-ray diffractor of the plurality of X-ray diffractors is a single crystal, at least one X-ray diffractor of the plurality of X-ray diffractors is a mosaic crystal, and / or the plurality of X-ray diffractors includes both at least one single crystal and at least one mosaic crystal.

16. The device according to claim 1, wherein The first X-ray diffractor has a thickness in a direction along which the X-rays received by the first X-ray diffractor propagate, the thickness being less than 500 micrometers.

17. The device according to claim 1, wherein: At least one X-ray diffractor of the plurality of X-ray diffractors is cut asymmetrically.

18. The device according to claim 1, wherein: At least one X-ray diffractor of the plurality of X-ray diffractors is substantially planar.

19. The device according to claim 1, wherein: At least one X-ray diffractor of the plurality of X-ray diffractors is curved in at least one direction.

20. The device according to claim 1, wherein The first X-ray diffractor is configured to diffract characteristic X-rays of trace atomic elements of the X-ray source, and the second X-ray diffractor is configured to diffract characteristic X-rays of other atomic elements of the X-ray source.

21. The device according to claim 1, wherein An X-ray diffractor of the plurality of X-ray diffractors downstream of all other X-ray diffractors in the plurality of X-ray diffractors is substantially non-transmissive to the X-rays.

22. The apparatus according to claim 1, further comprising at least one motion stage configured to move at least one X-ray diffractor of the plurality of X-ray diffractors to adjust an incident angle of the X-ray to the at least one X-ray diffractor.

23. The device according to claim 1, wherein At least one X-ray detector of the plurality of X-ray detectors is selected from the group consisting of: an ionization chamber; a proportional counter; a scintillation counter; a PIN diode; a silicon drift detector; a pixel of a pixel array detector.

24. The device according to claim 1, wherein: At least one X-ray detector of the plurality of X-ray detectors comprises a pixel array detector extending in at least one dimension.

25. The device according to claim 1, wherein At least one X-ray detector among the multiple X-ray detectors includes a photon counting pixel array detector having at least one energy threshold, which is configured to reject X-rays having energy below the at least one energy threshold and / or reject X-rays having energy above the at least one energy threshold.

26. The device according to claim 1, wherein Each of the first X-ray diffractor and the second X-ray diffractor includes a substantially flat crystal.

27. The device according to claim 1, wherein The first X-ray diffractor includes a first generally curved crystal and the second X-ray diffractor includes a second generally curved crystal.

28. The device according to claim 27, wherein The first generally curved crystal includes a first von Hamos crystal having a corresponding first longitudinal axis, and the second generally curved crystal includes a second von Hamos crystal having a corresponding second longitudinal axis at an angle greater than 0.1 mrad relative to the first longitudinal axis.

29. The device according to claim 27, wherein: At least one of the first generally curved crystal and the second generally curved crystal comprises a von Hammers crystal, a Johann crystal, or a Johnson crystal.

30. The device according to claim 1, wherein The first X-ray diffractor comprises a substantially flat crystal and the second X-ray diffractor comprises a substantially curved crystal.

31. The device according to claim 30, wherein The generally curved crystal comprises a von Hammers crystal, a Johann crystal or a Johnson crystal.

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