Method of operating a spectrometer

Abstract

A method of operating a spectrometer includes positioning a crystal analyzer such that a first reciprocal lattice vector corresponding to a first crystal surface of the crystal analyzer is coplanar with a source axis and a detector axis; and performing a first scan by changing a first angle between the source axis and the first crystal plane and changing a second angle between the detector axis and the first crystal plane such that the first angle is substantially equal to the second angle; rotating the crystal analyzer such that a second reciprocal lattice vector corresponding to a second crystal surface of the crystal analyzer is coplanar with the source axis and the detector axis; and performing a second scan by changing the first angle and changing the second angle such that the first angle is substantially equal to the second angle.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 510,518, filed June 27, 2023, the entire contents of which are incorporated herein by reference.

[0002] Statement regarding federally funded research or development This invention was completed with government support from the U.S. Department of Energy, grant number DE-NE0009158. The government holds certain rights to this invention. Background Technology

[0003] Many X-ray spectrometers use a curved crystal analyzer (CCA) as a monochromator to selectively scatter or transmit X-rays emitted from or through a sample of material being tested. CCAs are typically fabricated by gluing or bonding silicon or germanium wafers to a concave glass lens or other concave form. The crystal orientation of the wafer surface is chosen such that the lattice spacing of the nominally parallel crystal planes is adapted by Bragg's law to produce constructive interference of X-rays in the energy or wavelength range of interest. However, studying the response of a sample in different energy or wavelength ranges using the same spectrometer often requires a second CCA. The second CCA is chosen such that the nominally parallel crystal planes have a different lattice spacing than the original CCA. Removing the CCA from the spectrometer to investigate different wavelength or energy ranges can be tedious and time-consuming. Summary of the Invention

[0004] The first example is a method of operating a spectrometer including a crystal analyzer defining a Rowland circle, a source configured to emit X-rays along a source axis, and a detector configured to detect X-rays traveling along a detector axis. The method includes: positioning the crystal analyzer such that a first reciprocal lattice vector corresponding to a first crystal plane of the crystal analyzer is coplanar with the source axis and the detector axis; performing a first scan while the first reciprocal lattice vector is coplanar with the source axis and the detector axis, by changing a first angle between the source axis and the first crystal plane and changing a second angle between the detector axis and the first crystal plane such that the first angle is substantially equal to the second angle; rotating the crystal analyzer such that a second reciprocal lattice vector corresponding to a second crystal plane of the crystal analyzer is coplanar with the source axis and the detector axis; and performing a second scan while the second reciprocal lattice vector is coplanar with the source axis and the detector axis, by changing the first angle and changing the second angle such that the first angle is substantially equal to the second angle.

[0005] The second example is a non-transitory computer-readable medium storing instructions that, when executed by one or more processors of the spectrometer, cause the spectrometer to perform the method of the first example.

[0006] A third example is a spectrometer comprising: a source configured to emit X-rays along a source axis; a detector configured to detect X-rays traveling along a detector axis; an analyzer stage configured to hold a crystal analyzer defining a Rowland circle, wherein the analyzer stage is configured to rotate the crystal analyzer about an analyzer axis coplanar with the source axis and the detector axis; and an alignment device comprising: a source stage configured to hold the source; a detector stage configured to hold the detector; and a goniometer configured to (i) adjust a fifth angle between the analyzer stage and the detector axis and (ii) adjust a sixth angle between the analyzer stage and the source axis, wherein the alignment device is configured to move the source stage, the detector stage, and / or the analyzer stage to adjust a first distance between the source and the analyzer stage along the source axis and to adjust a second distance between the detector and the analyzer stage along the detector axis.

[0007] The following reference is incorporated herein by reference: Anthony J. Gironda et al., “Asymmetric Rowland circle geometry for spherical bending crystal analyzers for laboratory and synchrotron applications.” J. Anal. At. Spectrom., 2024, 39, 1375. https: / / pubs.rsc.org / en / content / articlelanding / 2024 / ja / d3ja00437f.

[0008] When the terms “basic” or “approximately” are used herein, it means that the described characteristic, parameter, or value does not need to be precisely achieved, but deviations or variations known to those skilled in the art, including, for example, tolerances, measurement errors, measurement accuracy limitations, and other factors, may arise in quantities not large enough to prevent the effect that the characteristic was originally intended to provide. In some instances disclosed herein, “basic” or “approximately” means within + / - 0-5% of the stated value.

[0009] These and other aspects, advantages, and alternatives will become apparent to those skilled in the art upon reading the following detailed description and, where appropriate, referring to the accompanying drawings. Furthermore, it should be understood that the summary and other descriptions provided herein, along with the accompanying drawings, are intended to illustrate the invention by way of example only, and therefore, many variations are possible. Attached Figure Description

[0010] Figure 1 It is a block diagram of the spectrometer in the example.

[0011] Figure 2 This is a schematic diagram of a spectrometer configured for operation in asymmetric mode, based on an example.

[0012] Figure 3A This is a schematic diagram of a spectrometer configured to perform X-ray absorption fine structure (XAFS) scanning, based on an example.

[0013] Figure 3B This is a schematic diagram of a spectrometer configured to perform X-ray emission spectroscopy (XES) scans, based on an example.

[0014] Figure 4A This is a schematic diagram of the analyzer stand and crystal analyzer based on the example.

[0015] Figure 4B This is a schematic diagram of the analyzer stand and crystal analyzer based on the example.

[0016] Figure 4C This is a schematic diagram of the analyzer stand and crystal analyzer based on the example.

[0017] Figure 5 This is a schematic diagram of a spectrometer configured for operation in asymmetric mode, based on an example.

[0018] Figure 6 It is a flowchart based on the example method.

[0019] Figure 7A This is a schematic diagram of a spectrometer configured for operation in symmetric mode, based on an example.

[0020] Figure 7B This is a schematic diagram of a spectrometer configured for operation in asymmetric mode, based on an example.

[0021] Figure 8A The degree of Johan error based on the incident position of X-rays on the crystal analyzer during operation in a symmetrical configuration according to the example is shown.

[0022] Figure 8B The John error level based on the incident position of the X-ray on the crystal analyzer during operation in an asymmetric configuration, according to an example, is shown.

[0023] Figure 9 The calculated values ​​and experimental results for (α, φ) of several crystal planes corresponding to the Si (551) crystal analyzer are shown according to the example. Detailed Implementation

[0024] There is a need for a method of operating a spectrometer that does not require the use of a different curved crystal analyzer (CCA) when studying the response of a sample over a wide wavelength or energy range. Therefore, this disclosure includes such a spectrometer and its operating method.

[0025] A spectrometer includes a source, such as an X-ray tube, and a detector, such as a silicon drift detector, the source being configured to emit X-rays along a source axis and the detector being configured to detect X-rays traveling along a detector axis. The spectrometer also includes an analyzer stage configured to hold a crystal analyzer defining a Rowland circle. The analyzer stage is configured to rotate the crystal analyzer about an analyzer axis coplanar with the source axis and the detector axis. The spectrometer also includes an alignment device comprising a source stage configured to hold the source. The spectrometer also includes a detector stage configured to hold the detector. The spectrometer further includes a goniometer configured to (i) adjust an angle between the analyzer stage and the detector axis and (ii) adjust an angle between the analyzer stage and the source axis. The alignment device is configured to move the source stage, the detector stage, and / or the analyzer stage to adjust a first distance between the source and the analyzer stage along the source axis and a second distance between the detector and the analyzer stage along the detector axis.

[0026] The method of operating the spectrometer includes positioning the crystal analyzer such that a first reciprocal lattice vector corresponding to a first crystal plane of the crystal analyzer is coplanar with the source axis and the detector axis. The method further includes performing a first scan while simultaneously changing a first angle between the source axis and the first crystal plane and changing a second angle between the detector axis and the first crystal plane to make the first angle substantially equal to the second angle. The method also includes rotating the crystal analyzer such that a second reciprocal lattice vector corresponding to a second crystal plane of the crystal analyzer is coplanar with the source axis and the detector axis. Finally, the method further includes performing a second scan while simultaneously changing a first angle and a second angle to make the first angle substantially equal to the second angle.

[0027] Conventional X-ray spectrometers are typically used only in a symmetrical configuration, where (i) the entrance or exit slits of the source and detector are equidistant from the crystal analyzer, and (ii) the angle formed by the source axis and the detector axis is bisected by a reciprocal lattice vector corresponding to a crystal plane nominally parallel to the surface of the crystal analyzer. Conversely, the first and / or second scans of the aforementioned method are performed in an asymmetrical configuration defined by: (i) the entrance or exit slits of the source and detector are not equidistant from the crystal analyzer, and (ii) the angle formed by the source axis and the detector axis is bisected by a reciprocal lattice vector not nominally parallel to the surface of the crystal analyzer.

[0028] Asymmetric configurations offer at least three advantages. First, they allow the use of a single crystal analyzer to study sample responses over a wide wavelength or energy range. This saves time compared to symmetric configurations because multiple overlapping or non-overlapping energy ranges can be studied without removing the first crystal analyzer from the analyzer stage and inserting and calibrating a second. For example, the entire energy range from 5 keV to 10 keV can be easily studied before each new scan by rotating one crystal analyzer and properly positioning the source and detector. Second, John Johann errors can be significantly reduced or eliminated because the angle between the source axis and the central surface of the crystal analyzer can be maintained very large. Third, asymmetric configurations can significantly increase the distance clearance between the source and detector.

[0029] Figure 1 This is a block diagram of a spectrometer 200. The spectrometer 200 includes a computing device 100. The computing device 100 includes one or more processors 102, a non-transitory computer-readable medium 104, a communication interface 106, and a user interface 108. The components of the computing device 100 are linked together via a system bus, network, or other connection mechanism 112.

[0030] One or more processors 102 may be any type of processor coupled to non-transitory computer-readable medium 104, such as microprocessors, field-programmable gate arrays, digital signal processors, multi-core processors, etc.

[0031] The non-transitory computer-readable medium 104 can be any type of memory, such as volatile memory, like random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), or non-volatile memory, like read-only memory (ROM), flash memory, magnetic disk or optical disk, or optical disk read-only memory (CD-ROM), and other devices for storing data or programs on a temporary or permanent basis.

[0032] Additionally, the non-transitory computer-readable medium 104 may store instructions 111. Instructions 111 may be executed by one or more processors 102 to cause the computing device 100 to perform any of the functions or methods described herein.

[0033] Communication interface 106 may include hardware to enable communication within computing device 100 and / or between computing device 100 and one or more other devices. The hardware may include any type of input and / or output interface, such as Universal Serial Bus (USB), PCI Express, transmitter, receiver, and antenna. Communication interface 106 may be configured to facilitate communication with one or more other devices according to one or more wired or wireless communication protocols. For example, communication interface 106 may be configured to facilitate wireless data communication of computing device 100 according to one or more wireless communication standards, such as one or more Institute of Electrical and Electronics Engineers (IEEE) 801.11 standards, ZigBee standards, Bluetooth standards, etc. As another example, communication interface 106 may be configured to facilitate wired data communication with one or more other devices. Communication interface 106 may also include an analog-to-digital converter (ADC) or a digital-to-analog converter (DAC), which computing device 100 may use to control various components of computing device 100 or external devices.

[0034] User interface 108 may include any type of display component configured to display data. As an example, user interface 108 may include a touchscreen display. As another example, user interface 108 may include a flat panel display, such as a liquid crystal display (LCD) or a light-emitting diode (LED) display. User interface 108 may include one or more hardware components for providing data and control signals to computing device 100. For example, user interface 108 may include a mouse or pointing device, a keyboard or keypad, a microphone, a touchpad or touchscreen, and other possible types of user input devices. Typically, user interface 108 enables an operator to interact with a graphical user interface (GUI) provided by computing device 100 (e.g., displayed by user interface 108).

[0035] The spectrometer 200 also includes a source 202, a detector 206, and an analyzer stage 210. The spectrometer 200 also includes an alignment device 221, which includes a source stage 218, a detector stage 220, a goniometer 222, and one or more motors 224.

[0036] Figure 2This is a schematic diagram of a spectrometer 200. The spectrometer 200 includes a source 202 configured to emit X-rays along a source axis 204. The X-rays emitted by the source 202 along the source axis 204 are generally divergent and not collimated, but the X-rays are generally strongest along the source axis 204. The spectrometer 200 also includes a detector 206 configured to detect X-rays traveling along a detector axis 208. The spectrometer 200 also includes an analyzer stage 210 configured to hold a crystal analyzer 212 defining a Rowland circle 214. The analyzer stage 210 is configured to rotate the crystal analyzer 212 about an analyzer axis 216 that is coplanar with the source axis 204 and the detector axis 208. The spectrometer 200 also includes a source stage 218. In some examples, the source stage 218 is configured to move the source 202 toward or away from the analyzer stage 210 along the source axis 204. In some examples, goniometer 222 is configured to move analyzer stage 210 toward or away from source 202 along source axis 204. Spectrometer 200 also includes detector stage 220. In some examples, detector stage 220 is configured to move detector 206 toward or away from analyzer stage 210 along detector axis 208. In some examples, goniometer 222 is configured to move analyzer stage 210 toward or away from detector 206 along detector axis 208. Spectrometer 200 also includes a double-circle goniometer 222 (shown in Figure 3), configured to (i) adjust the angle 225 between analyzer stage 210 and detector axis 208, and (ii) adjust the angle θ between analyzer stage 210 and source axis 204. M Alignment device 221 (e.g., source stage 218, detector stage 220, goniometer 222 and / or one or more motors 224) is configured to move source stage 218, detector stage 220 and / or analyzer stage 210 to adjust the distance ρ between source 202 and analyzer stage 210 along source axis 204 and the distance d between detector 206 and analyzer stage 210 along detector axis 208.

[0037] The diameter of Rowland circle 214 is equal to the radius of curvature of crystal analyzer 212. Crystal analyzer 212 can take the form of a spherically bent crystal analyzer. Rowland circle 214 is tangent to the central surface of crystal analyzer 212.

[0038] Source 202 may take the form of an X-ray tube, a sample irradiated by an X-ray tube, or a synchrotron. In various examples, the sample under test may be located on source stage 218 together with source 202. Source 202 includes an entrance slit 226 on Rowland circle 214. Source stage 218 is a platform configured to fix source 202 and prevent unintended movement of source 202. Motor 224A is configured to move source stage 218 back and forth along source axis 204.

[0039] Detector 206 may be in the form of a silicon drift detector and includes an exit slit 228 on a Rowland circle 214. In various examples, the sample under test may be located on a detector stage 220 having detector 206. Detector stage 220 is a platform configured to fix detector 206 and prevent unintended movement of detector 206. Motor 224B is configured to move detector stage 220 back and forth along detector axis 208.

[0040] The analyzer stage 210 is a platform configured to fix the crystal analyzer 212 and prevent unintended movement of the crystal analyzer 212. Therefore, the analyzer stage 210 may include a clamping part under tension, which holds the crystal analyzer 212 in place. The motor 224C is configured to rotate the analyzer stage 210 and the crystal analyzer 212 about the analyzer axis 216.

[0041] The goniometer 222 (shown in Figure 3) is a mechanical device configured to rotate the detector stage 220 and the source stage 218 relative to the analyzer stage 210. One or more motors 224 are configured to operate the goniometer 222. For example, motor 224D is configured to adjust angle 225, and motor 224E is configured to adjust angle θ. M In some examples, motor 224F is configured to move analyzer stage 210 such that distance ρ increases or decreases, and motor 224G is configured to move analyzer stage 210 such that distance d increases or decreases.

[0042] Figure 3A and Figure 3B The operation of the spectrometer 200 in two different modes is shown. Figure 3A A spectrometer 200 is shown performing X-ray absorption fine structure (XAFS) spectroscopy, which is a transmission mode in which the spectrometer 200 generates a tunable intensity spectrum of the energy of X-rays transmitted through the sample. As shown, the sample is located on detector stage 220.

[0043] Figure 3B A spectrometer 200 performing X-ray emission spectroscopy (XES) as emission mode is shown. As shown, the sample is located on source stage 218. This geometry also applies when the spectrometer 200 is used to perform wavelength dispersive X-ray fluorescence spectroscopy (WD-XRF). In various examples, the spectrometer 200 can operate in emission mode, absorption mode, transmission mode, or fluorescence mode. In fluorescence mode, the sample is approximately on Rowland circle 214, and detector 206 is typically above Rowland circle 214.

[0044] Figure 4A , Figure 4B and Figure 4CThis is a schematic diagram of the analyzer stage 210 and the crystal analyzer 212. The analyzer stage 210 is configured to allow the crystal analyzer 212 to rotate about the analyzer axis 216 (see [reference]). Figure 2 Therefore, the rotation angle φ is defined as a plane perpendicular to the analyzer axis 216.

[0045] refer to Figure 2 The spectrometer 200 positions the crystal analyzer 212 so that the reciprocal lattice vector G corresponding to the crystal plane A at the center of the crystal analyzer 212 is... A It is coplanar with the source axis 204 and the detector axis 208. Typically, the analyzer stage 210 is rotated about the analyzer axis 216 manually or using a motor 224C, causing the reciprocal lattice vector G... A It is coplanar with Rowland circle 214. In a specific instance, the reciprocal lattice vector G... A For G 5，5，1 This means that the spectrometer 200 positions the crystal analyzer 212 such that the 5, 5, 1 plane of the (e.g., silicon) crystal analyzer 212 is perpendicular to the Rowland circle 214. In an example where the spectrometer 200 operates in a symmetrical configuration, the crystal plane A of the crystal analyzer 212 is nominally parallel to the central surface of the crystal analyzer 212. In other examples where the spectrometer 200 operates in an asymmetrical configuration, the crystal plane A of the crystal analyzer 212 is not nominally parallel to the central surface of the crystal analyzer 212.

[0046] Before and simultaneously with performing the first scan, the spectrometer 200 translates the source 202 and / or the crystal analyzer 212 such that (i) the source axis 204 is aligned with the detector axis 208 and the reciprocal lattice vector G. A They are coplanar, and (ii) the source distance ρ between source 202 and crystal analyzer 212 along source axis 204 is approximately equal to the diameter D of the Rowland circle multiplied by (a) the angle θ formed by source axis 204 and crystal plane A. B (b) The sine of the sum of angles α formed by crystal plane A and crystal plane C, which is nominally parallel to the curved center surface of crystal analyzer 212. This relationship is expressed by the following equation: The source 202 can be moved by adjusting the position of the source stage 218 manually or via motor 224A. The crystal analyzer 212 can be moved by moving the analyzer stage 210, for example using motor 224F.

[0047] Similarly, before and simultaneously with performing the first scan, the spectrometer 200 translates the detector 206 and / or the crystal analyzer 212 such that (i) the detector axis 208 is aligned with the source axis 204 and the reciprocal lattice vector G. AThey are coplanar, and (ii) the detector distance d along the detector axis 208 between detector 206 and crystal analyzer 212 is approximately equal to the diameter D of Rowland circle 214 multiplied by (a) the angle θ formed by detector axis 208 and crystal plane A. B Subtracting the sine of the difference in angle α formed by crystal planes A and C (b), the relationship is expressed by the following equation: The spectrometer 200 can translate the detector 206 by manually or via motor 224B adjusting the placement of the detector stage 220. The spectrometer 200 can translate the crystal analyzer 212 by translating the analyzer stage 210, for example using motor 224G.

[0048] Then, the spectrometer 200 at the reciprocal lattice vector G A The first scan is performed simultaneously with the source axis 204 and the detector axis 208 being coplanar. Performing the first scan involves the goniometer 222 changing the angle θ between the source axis 204 and the crystal plane A. B And change the angle θ between detector axis 208 and crystal plane A. B During the first scan, the angle θ B The X-rays are kept substantially equal to each other. The first scan also includes detector 206 detecting monochromatic X-rays from crystal analyzer 212 while changing angle θ. B .

[0049] In either transmission or absorption configuration, source 202 irradiates crystal analyzer 212 with a first X-ray, causing a second X-ray to be emitted from crystal analyzer 212 via Bragg reflection and incident on the sample. Detector 206 detects the second X-ray transmitted through the sample.

[0050] In the emission configuration, source 202 irradiates the sample with first X-rays, causing the sample to emit second X-rays that are incident on crystal analyzer 212. These X-rays enter the Rowland circle through entrance slit 226 on source stage 218. Detector 206 then detects the third X-rays reflected from crystal analyzer 212 via Bragg reflection of the second X-rays.

[0051] Regardless of the configuration of the first scan, the spectrometer 200 generates a tunable intensity spectrum of the X-ray energy detected by the detector 206. For example, if the reciprocal lattice vector G A Corresponding to the 5, 1, 1 plane of silicon, the energy range of the first scan corresponds to approximately 8.3 keV to 9.4 keV.

[0052] Figure 5 The spectrometer 200 performing the second scan is shown. To begin the second scan, the spectrometer 200 rotates the crystal analyzer 212 about the analyzer axis 216, such that the reciprocal lattice vector G corresponding to the crystal plane B at the center of the crystal analyzer 212 is rotated.B It is coplanar with the source axis 204 and the detector axis 208. Typically, the analyzer stage 210 is rotated about the analyzer axis 216 manually or using a motor 224C, causing the reciprocal lattice vector G... B It is coplanar with Rowland circle 214. In a specific instance, the reciprocal lattice vector G... B For G 3，5，-1 This means that the spectrometer 200 positions the crystal analyzer 212 such that the 3, 5, -1 plane at the center of the (e.g., silicon) crystal analyzer 212 is perpendicular to the Rowland circle 214. In an example where the spectrometer 200 operates in a symmetrical configuration, the crystal plane B of the crystal analyzer 212 is nominally parallel to the central surface of the crystal analyzer 212. In other examples where the spectrometer 200 operates in an asymmetrical configuration, the crystal plane B of the crystal analyzer 212 is not nominally parallel to the central surface of the crystal analyzer 212.

[0053] Before and simultaneously with the second scan, the spectrometer 200 translates the source 202 and / or the crystal analyzer 212 such that (i) the source axis 204 is aligned with the detector axis 208 and the reciprocal lattice vector G. B They are coplanar, and (ii) the source distance ρ between source 202 and crystal analyzer 212 along source axis 204 is approximately equal to the diameter D of the Rowland circle multiplied by (a) the angle θ formed by source axis 204 and crystal plane B. B The sine of the sum of angles α formed by crystal plane B and crystal plane C, which is nominally parallel to the curved center surface of crystal analyzer 212. This relationship is expressed by the following equation: The source 202 can be moved by adjusting the position of the source stage 218 manually or via motor 224A. The crystal analyzer 212 can be moved by moving the analyzer stage 210, for example using motor 224F.

[0054] Similarly, before and simultaneously with the second scan, the spectrometer 200 translates the detector 206 and / or the crystal analyzer 212 such that (i) the detector axis 208 is aligned with the source axis 204 and the reciprocal lattice vector G. B They are coplanar, and (ii) the detector distance d along the detector axis 208 between detector 206 and crystal analyzer 212 is approximately equal to the diameter D of Rowland circle 214 multiplied by (a) the angle θ formed by detector axis 208 and crystal plane B. B Subtracting the sine of the difference in angle α formed by crystal planes B and C (b), the relationship is expressed by the following equation: The spectrometer 200 can translate the detector 206 by manually or via motor 224B adjusting the placement of the detector stage 220. The spectrometer 200 can translate the crystal analyzer 212 by translating the analyzer stage 210, for example using motor 224G.

[0055] Then, the spectrometer 200 at the reciprocal lattice vector G B The second scan is performed simultaneously with the source axis 204 and the detector axis 208 being coplanar. Performing the second scan involves the goniometer 222 changing the angle θ between the source axis 204 and the crystal plane B. B And change the angle θ between detector axis 208 and crystal plane B. B During the second scan, angle θ B The two scans are kept substantially equal. The second scan also involves detector 206 detecting monochromatic X-rays from crystal analyzer 212 while changing angle θ. B .

[0056] In either transmission or absorption configuration, source 202 irradiates crystal analyzer 212 with a first X-ray, causing a second X-ray to be emitted from crystal analyzer 212 via Bragg reflection and incident on the sample. Detector 206 detects the second X-ray transmitted through the sample.

[0057] In the emission configuration, source 202 irradiates the sample with a first X-ray, causing the sample to emit a second X-ray that is incident on crystal analyzer 212. The second X-ray enters the Rowland circle through entrance slit 226 on source stage 218. Then, detector 206 detects a third X-ray reflected from crystal analyzer 212 via Bragg reflection of the second X-ray.

[0058] Regardless of the configuration of the second scan, the spectrometer 200 generates an intensity spectrum of the energy of the X-rays detected by the detector 206. For example, if the reciprocal lattice vector G B Corresponding to the 3, 5, -1 plane of silicon, the energy range of the second scan corresponds to approximately 6.5 keV to 8.1 keV.

[0059] Figure 6 This is a flowchart of method 300. (Example) Figure 6 As shown, method 300 includes one or more operations, functions, or actions as illustrated in boxes 302, 304, 306, and 308. Although the boxes are described in sequential order, they may also be executed in parallel and / or in an order different from that described herein. Moreover, depending on the desired implementation, individual blocks may be merged into fewer blocks, split into additional blocks, and / or removed.

[0060] In block 302, method 300 includes: the spectrometer 200 or the user positioning the crystal analyzer 212 such that the reciprocal lattice vector G corresponding to the crystal plane A of the crystal analyzer 212... A It is coplanar with the source axis 204 and the detector axis 208. (See above for reference.) Figure 2 The functions related to block 302 are discussed up to Figure 4.

[0061] In box 304, method 300 includes: when the reciprocal lattice vector G A When the source axis 204 and the detector axis 208 are coplanar, the spectrometer 200 changes the angle θ between the source axis 204 and the crystal plane A. B And changing the angle θ between detector axis 208 and crystal plane A. B To perform the first scan, the angle θ between the source axis 204 and the crystal plane A is... B It is approximately equal to the angle θ between detector axis 208 and crystal plane A. B The above is for reference. Figure 2 The functions related to box 304 are discussed up to Figure 4.

[0062] In block 306, method 300 includes: a spectrometer 200 or a user-rotated crystal analyzer 212, such that the reciprocal lattice vector G corresponding to the crystal plane B of the crystal analyzer 212... B It is coplanar with the source axis 204 and the detector axis 208. (See above) Figures 2 to 5 Discuss the functionality related to box 306.

[0063] In box 308, method 300 includes: a spectrometer 200 on the reciprocal lattice vector G B While being coplanar with both the source axis 204 and the detector axis 208, the angle θ between the source axis 204 and the crystal plane B is changed. B And change the angle θ between detector axis 208 and crystal plane B. B To perform the second scan, the angle θ between the source axis 204 and the crystal plane B is adjusted. B It is approximately equal to the angle θ between detector axis 208 and crystal plane B. B The functions related to box 304 are shown in Figures 3 to 4 above. Figure 5 A discussion was held.

[0064] Figure 7A A spectrometer 200 is shown, configured to perform XAFS in a symmetric configuration. In the symmetric configuration, the Bragg angle θ B The angle θ between the source axis 204 and the crystal plane C, which is nominally parallel to the central surface of the crystal analyzer 212, is equal to the angle between the source axis 204 and the crystal plane C. M .

[0065] Figure 7B A spectrometer 200 is shown, configured to perform XAFS in an asymmetric configuration. In the asymmetric configuration, the Bragg angle θ B Not equal to angle θ MThe asymmetric configuration allows for Bragg angles such as 65°, while X-rays from source 202 are incident on crystal analyzer 212 at large angles such as 90°. Although using Bragg angles much smaller than 90 degrees, this high incident angle on crystal analyzer 212 can produce high signal intensity in conjunction with reduced or eliminated John john errors.

[0066] Figure 8A The study shows a significant John error that occurs when operating in a symmetrical configuration for X-rays incident on the crystal analyzer with an eccentricity of more than approximately 10 mm.

[0067] Figure 8B The results show that when operating in an asymmetric configuration, the John error is close to zero for X-rays incident on the crystal analyzer with an eccentricity of less than approximately 40 mm.

[0068] Figure 9 The calculated and experimental values ​​of (α, φ) for several crystal planes of the Si(551) crystal analyzer are shown. The asymmetry angle α corresponds to the radial direction, and the rotation angle φ corresponds to the azimuth direction. For example, the 733 crystal plane of the Si(551) crystal analyzer corresponds to approximately α = 25° and φ = 120°.

[0069] While various exemplary aspects and exemplary embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various exemplary aspects and exemplary embodiments disclosed herein are for illustrative purposes and are not intended to be limiting; the true scope and spirit are indicated by the appended claims.

Claims

1. A method of operating a spectrometer, the spectrometer comprising a crystal analyzer defining a Rowland circle, a source configured to emit x-rays along a source axis, and a detector configured to detect x-rays traveling along a detector axis, the method comprising: Position the crystal analyzer such that the first reciprocal lattice vector corresponding to the first crystal plane of the crystal analyzer is coplanar with the source axis and the detector axis. While the first reciprocal lattice vector is coplanar with the source axis and the detector axis, the first scan is performed by changing the first angle between the source axis and the first crystal plane and changing the second angle between the detector axis and the first crystal plane so that the first angle is substantially equal to the second angle. Rotate the crystal analyzer such that the second reciprocal lattice vector corresponding to the second crystal plane of the crystal analyzer is coplanar with the source axis and the detector axis; and While the second reciprocal lattice vector is coplanar with the source axis and the detector axis, a second scan is performed by changing the first angle and changing the second angle so that the first angle is substantially equal to the second angle.

2. The method according to claim 1, wherein the crystal analyzer is a spherical bending crystal analyzer.

3. The method according to any one of claims 1 to 2, wherein the diameter of the Rowland circle is equal to the radius of curvature of the crystal analyzer.

4. The method according to any one of claims 1 to 3, wherein the source comprises an X-ray tube or a synchrotron.

5. The method according to any one of claims 1 to 4, wherein performing the first scan further comprises: The sample is irradiated with a first X-ray using the source, causing the sample to emit a second X-ray that is incident on the crystal analyzer. as well as The detector is used to detect the third X-ray reflected from the crystal analyzer via the Bragg reflection of the second X-ray.

6. The method of claim 5, wherein performing the first scan and performing the second scan each comprise performing x-ray emission spectroscopy (XES).

7. The method of claim 5, wherein performing the first scan and performing the second scan each comprise performing wavelength dispersive X-ray fluorescence spectroscopy (WD-XRF).

8. The method according to any one of claims 1 to 4, wherein performing the first scan further comprises: The source is used to irradiate the crystal analyzer with a first X-ray, such that a second X-ray is emitted from the crystal analyzer via Bragg reflection and incident on the sample; as well as The detector is used to detect the second X-rays that have penetrated through the sample.

9. The method according to claim 8, wherein, Performing the first scan and performing the second scan each include performing X-ray absorption fine structure (XAFS) analysis.

10. The method according to any one of claims 1 to 9, wherein the source comprises an entrance slit on the Rowland circle.

11. The method according to any one of claims 1 to 10, wherein the detector comprises an entrance slit on the Rowland circle.

12. The method according to any one of claims 1 to 11, wherein performing the first scan comprises: The source and / or the crystal analyzer are translated such that (i) the source axis is coplanar with the detector axis and the first reciprocal lattice vector, and (ii) the source distance between the source and the crystal analyzer along the source axis is substantially equal to the diameter of the Rowland circle multiplied by the sine of the sum of (a) the first angle and (b) the third angle formed by the first crystal plane and the third crystal plane that is nominally parallel to the curved surface of the crystal analyzer.

13. The method of claim 12, wherein performing the second scan comprises: The source and / or the crystal analyzer are translated such that (i) the source axis is coplanar with the detector axis and the second reciprocal lattice vector, and (ii) the source distance is substantially equal to the diameter of the Rowland circle multiplied by the sine of the second sum of (a) the first angle and (b) the fourth angle formed by the second crystal plane and the third crystal plane.

14. The method according to any one of claims 1 to 13, wherein performing the first scan comprises: The detector and / or the crystal analyzer are translated such that (i) the detector axis is coplanar with the source axis and the first reciprocal lattice vector, and (ii) the detector distance between the detector and the crystal analyzer along the detector axis is substantially equal to the diameter of the Rowland circle multiplied by (a) the first angle minus (b) the sine of the difference between the first crystal plane and the third crystal plane, which is nominally parallel to the curved surface of the crystal analyzer.

15. The method of claim 14, wherein performing the second scan comprises: The detector and / or the crystal analyzer are translated such that (i) the detector axis is coplanar with the source axis and the second reciprocal lattice vector, and (ii) the detector distance is substantially equal to the diameter of the Rowland circle multiplied by (a) the first angle minus (b) the sine of the second difference of the fourth angle formed by the second crystal plane and the third crystal plane.

16. The method according to any one of claims 1 to 15, wherein, Performing the first scan includes detecting monochromatic X-rays from the crystal analyzer while changing the first angle and the second angle.

17. The method according to any one of claims 1 to 16, wherein, Performing the second scan includes detecting monochromatic X-rays from the crystal analyzer while changing the first angle and the second angle.

18. The method according to any one of claims 1 to 17, wherein positioning the crystal analyzer such that the first reciprocal lattice vector is coplanar with the source axis and the detector axis comprises: The crystal analyzer is rotated about a rotation axis that is coplanar with the source axis and the detector axis.

19. The method according to any one of claims 1 to 18, wherein, Performing the first scan includes: detecting X-rays within a first energy range, and Performing the second scan includes detecting X-rays in a second energy range that does not overlap with the first energy range.

20. The method of claim 1, wherein performing the first scan comprises: The spectrometer is operated in emission mode, absorption mode, transmission mode, or fluorescence mode.

21. The method of claim 1, wherein performing the second scan comprises: The spectrometer is operated in emission mode, absorption mode, transmission mode, or fluorescence mode.

22. The method according to any one of claims 1 to 21, wherein rotating the crystal analyzer such that the second reciprocal lattice vector is coplanar with the source axis and the detector axis comprises: The crystal analyzer is rotated about a rotation axis that is coplanar with the source axis and the detector axis.

23. The method according to any one of claims 1 to 22, wherein the detector comprises a silicon drift detector.

24. A non-transitory computer-readable medium storing instructions that, when executed by one or more processors of a spectrometer, cause the spectrometer to perform the method according to any one of claims 1 to 23.

25. A spectrometer, comprising: The source is configured to emit X-rays along its source axis; A detector configured to detect X-rays traveling along the detector axis; An analyzer stage configured to maintain a crystal analyzer defining a Rowland circle, wherein the analyzer stage is configured to rotate the crystal analyzer about an analyzer axis coplanar with the source axis and the detector axis; and Alignment device, comprising: A source station, configured to hold the source; A detector stage, configured to hold the detector; and A goniometer is configured to: (i) adjust a fifth angle between the analyzer stage and the detector axis, and (ii) adjust a sixth angle between the analyzer stage and the source axis, wherein the alignment device is configured to move the source stage, the detector stage and / or the analyzer stage to adjust a first distance between the source and the analyzer stage along the source axis, and to adjust a second distance between the detector and the analyzer stage along the detector axis.

26. The spectrometer of claim 25, wherein the spectrometer is configured to perform the method of any one of claims 1 to 23.

27. The spectrometer according to any one of claims 25 to 26, wherein the alignment device further comprises a first motor configured to move the source stage along the source axis.

28. The spectrometer according to any one of claims 25 to 27, wherein the alignment device further comprises a second motor configured to move the detector stage along the detector axis.

29. The spectrometer according to any one of claims 25 to 28, wherein the goniometer includes one or more motors configured to adjust the fifth angle and the sixth angle.

30. The spectrometer according to any one of claims 25 to 29, wherein the alignment device includes a third motor configured to move the analyzer stage along the source axis.

31. The spectrometer according to any one of claims 25 to 30, wherein the alignment device includes a fourth motor configured to move the analyzer stage along the detector axis.

32. The spectrometer according to any one of claims 25 to 31, further comprising a fifth motor configured to rotate the analyzer stage about the analyzer axis.

33. The spectrometer according to any one of claims 25 to 32, wherein the crystal analyzer is a spherical bending crystal analyzer.

34. The spectrometer according to any one of claims 25 to 33, wherein the diameter of the Rowland circle is equal to the radius of curvature of the crystal analyzer.

35. The spectrometer according to any one of claims 25 to 34, wherein the source comprises an X-ray tube or a synchrotron.

36. The spectrometer according to any one of claims 25 to 35, wherein, The source includes the entrance slit on the Roland circle.

37. The spectrometer according to any one of claims 25 to 36, wherein the detector comprises an exit slit on the Rowland circle.

38. The spectrometer according to any one of claims 25 to 37, wherein the detector comprises a silicon drift detector.

39. The spectrometer according to any one of claims 24 to 38, further comprising: One or more processors; as well as A computer-readable medium storing instructions that, when executed by the one or more processors, cause the spectrometer to perform the method according to any one of claims 1 to 23.

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