High-resolution table type X-ray spectrometer and X-ray absorption spectrum testing method

Abstract

The invention discloses a distinguishing table type X-ray spectrometer and an X-ray absorption spectrum testing method, and relates to the technical field of spectral measurement. The high-resolution table type X-ray spectrometer comprises a sample signal source which is located in a Dowland circle and is used for generating X-rays; the exponential crystal is a bent crystal, the surface shape of the exponential crystal is defined by an exponential equation, so that different points on the curved surface of the crystal have different curvature radiuses and correspond to Rowland circles with different radiuses, each point on the exponential crystal is tangent to the corresponding Rowland circle, and the exponential crystal is used for performing monochromatization and focusing on the X-ray incident from the sample signal source; and the detector is positioned on a surface formed by the corresponding imaging points on each Rowland circle, and is used for receiving the X-rays which are monochromatized and focused by the index crystal and outputting corresponding light intensity signals. Therefore, through the cooperation of the index crystal and the multi-Rowland circle structure, the X-ray absorption spectrum test with high light receiving efficiency, high spectral resolution and wide energy spectrum range can be realized, and the comprehensive performance of the desk type spectrometer is improved.

Description

Technical Field

[0001] This invention relates to the field of spectral measurement technology, and in particular to a high-resolution benchtop X-ray spectrometer and an X-ray absorption spectroscopy testing method. Background Technology

[0002] In recent years, X-ray spectroscopy has developed rapidly. Advanced characterization techniques such as X-ray absorption fine structure spectroscopy (XAFS) based on synchrotron radiation have become important research directions for guiding the design of advanced materials and revealing the reaction mechanisms of catalysts. XAFS technology can analyze the local coordination environment and bond lengths of atoms in materials, providing unique structural information for materials science, catalysis chemistry, energy devices and other fields.

[0003] Synchrotron radiation sources emit electromagnetic radiation along the tangent of the orbit of charged particles (usually electrons) moving at near the speed of light in a magnetic field. Compared to traditional laboratory X-ray tubes, synchrotron radiation sources possess extremely high brightness (several orders of magnitude higher), a broad continuous spectrum (covering the band from far-infrared to hard X-rays), excellent collimation, and good polarization, earning them the reputation of a "super microscope" for studying the microstructure of matter. With these unique advantages, synchrotron radiation sources have revolutionized the methods of characterizing the microstructure of matter, allowing XAFS (Extracorporeal Analytic Frequency) technology to fully realize its analytical capabilities.

[0004] However, the development of synchrotron radiation sources has also been accompanied by significant limitations. First, there is the scarcity of resources: although global synchrotron radiation sources have reached the fourth generation (diffraction-limited sources), their construction costs are exorbitant and time allocation is extremely tight. Second, there is poor timeliness: researchers often have to wait months for a few days of experimental time, which severely conflicts with the demands of rapid iteration and high-frequency testing in modern scientific research. The scarcity of synchrotron radiation source time severely limits the widespread adoption of XAFS in scientific research and industrial applications.

[0005] To overcome these limitations of synchrotron radiation sources, benchtop X-ray spectrometers have been developed rapidly. However, existing benchtop X-ray spectrometers that can be deployed in laboratories have the following drawbacks: On the one hand, the traditional curved crystals used in this instrument (such as planar, cylindrical, conical, and spherical crystals) generally suffer from defects such as low photon collection efficiency, lack of Rowland circle structure, astigmatism caused by paraxial approximation, and John error, which result in significant limitations in spectral resolution, energy spectrum range, and sensitivity to light source size. On the other hand, the high-index crystals used in this instrument have significantly lower diffraction intensity than low-index crystals due to the combined effects of atomic scattering factor, structure factor, and temperature factor, which limits the instrument's detection sensitivity and signal-to-noise ratio.

[0006] Therefore, there is an urgent need to develop a benchtop X-ray spectrometer that can achieve precise point source imaging on large crystal shapes, with extremely high spectral resolution and high diffraction intensity, in order to improve laboratory-level X-ray spectroscopic testing capabilities. Summary of the Invention

[0007] The purpose of this invention is to propose a method for distinguishing between benchtop X-ray spectrometers and X-ray absorption spectroscopy testing, so as to achieve X-ray absorption spectroscopy testing with high light collection efficiency, high spectral resolution and wide energy range, thereby improving the overall performance of benchtop spectrometers.

[0008] In a first aspect, embodiments of the present invention provide a high-resolution benchtop X-ray spectrometer, comprising: a sample signal source, an exponential crystal, and a detector; the sample signal source is located inside a Rowland circle and is used to generate X-rays; the exponential crystal is a curved crystal whose surface shape is defined by an exponential equation, such that different points on the crystal surface have different radii of curvature and correspond to Rowland circles of different radii, each point on the exponential crystal being tangent to the corresponding Rowland circle, and the exponential crystal being used to monochromate and focus the X-rays incident from the sample signal source; the detector is located on the surface formed by the corresponding imaging points on each Rowland circle, and is used to receive the X-rays monochromated and focused by the exponential crystal and output a corresponding light intensity signal.

[0009] In some embodiments, the sample signal source includes an X-ray tube and a sample carrier: the sample carrier is disposed in front of the exit point of the X-ray tube and is used to place the sample; wherein the X-rays generated by the X-ray tube are absorbed by the sample and then irradiate the exponential crystal.

[0010] In some embodiments, the radius of curvature of the exponential crystal on the meridional plane is greater than the radius of curvature on the sagittal plane, forming an asymmetric curvature distribution.

[0011] In some embodiments, the exponential crystal employs a low-index crystal plane.

[0012] In some embodiments, the detector includes a detector body and a CMOS photosensitive element; the CMOS photosensitive element is disposed at the front end of the detector body and is used to receive X-rays after monochromatization and focusing by the exponential crystal, and convert the received X-ray signal into an electrical signal and transmit it to the detector body, so that the detector body outputs a light intensity signal characterizing the intensity of X-rays.

[0013] In some embodiments, the high-resolution benchtop X-ray spectrometer further includes a controller connected to the sample signal source, the detector, and the exponential crystal, respectively, for adjusting the distance between the sample signal source and the detector, and / or adjusting the crystal facets of the exponential crystal to obtain data in different energy ranges according to testing requirements.

[0014] Secondly, embodiments of the present invention provide an X-ray absorption spectroscopy testing method for use in the high-resolution benchtop X-ray spectrometer described in the first aspect embodiment. The sample signal source in the high-resolution benchtop X-ray spectrometer includes an X-ray tube and a sample carrier, the sample carrier being disposed in front of the exit point of the X-ray tube. The method includes the following steps: in response to a sample being placed on the sample carrier, the X-ray tube is turned on, so that the polychromatic X-rays generated by the X-ray tube irradiate the sample, and after absorption and attenuation by the sample, they are incident on the exponential crystal; and a first light intensity signal corresponding to the X-rays after monochromatization and focusing by the exponential crystal is obtained from the detector output; in response to a sample not being placed on the sample carrier, the X-ray tube is turned on, so that the polychromatic X-rays generated by the X-ray tube are incident on the exponential crystal; and a second light intensity signal corresponding to the X-rays after monochromatization and focusing by the exponential crystal is obtained from the detector output; X-ray absorption spectrum data is obtained based on the first light intensity signal and the second light intensity signal.

[0015] In some embodiments, obtaining X-ray absorption spectrum data based on the first light intensity signal and the second light intensity signal includes: calculating the absorption coefficient according to the formula μ(E)=ln(P0 / P1), where P0 is the second light intensity signal, P1 is the first light intensity signal, and μ(E) is the absorption coefficient; performing energy calibration, background subtraction, and normalization on the absorption coefficient to obtain a normalized absorption spectrum; and extracting the XAFS oscillation function from the normalized absorption spectrum to obtain the X-ray absorption spectrum data.

[0016] In some embodiments, before acquiring the first light intensity signal and the second light intensity signal, the method further includes: adjusting the distance between the sample signal source and the detector according to the energy range required for the test.

[0017] In some embodiments, before acquiring the first light intensity signal and the second light intensity signal, the method further includes: adjusting the crystal plane of the exponential crystal according to the energy range required for the test.

[0018] This invention discloses a high-resolution benchtop X-ray spectrometer and an X-ray absorption spectroscopy testing method. The high-resolution benchtop X-ray spectrometer includes: a sample signal source located inside a Doroland circle for generating X-rays; an exponential crystal, which is a curved crystal whose surface shape is defined by an exponential equation, such that different points on the crystal surface have different radii of curvature and correspond to Doroland circles of different radii. Each point on the exponential crystal is tangent to its corresponding Doroland circle. The exponential crystal is used to monochromate and focus the X-rays incident from the sample signal source; and a detector located on the surface formed by the corresponding imaging points on each Doroland circle, used to receive the X-rays monochromated and focused by the exponential crystal and output the corresponding light intensity signal. Thus, through the synergistic cooperation of the exponential crystal and the Doroland circle structure, high light-gathering efficiency, high spectral resolution, and a wide energy spectral range of X-ray absorption spectroscopy testing can be achieved, improving the overall performance of the benchtop spectrometer. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a high-resolution benchtop X-ray spectrometer according to an embodiment of the present invention; Figure 2 This is a schematic diagram of an exponential crystal and a doroland circle structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a sample signal source according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the detector structure according to an embodiment of the present invention; Figure 5 This is a flowchart of the X-ray absorption spectroscopy testing method according to an embodiment of the present invention; Figure 6 This is a K-edge XAS image of an S element tested in an example of the present invention. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following description, with reference to the accompanying drawings, illustrates an embodiment of the high-resolution benchtop X-ray spectrometer and an X-ray absorption spectroscopy testing method of the present invention.

[0022] Example 1: High-resolution benchtop X-ray spectrometer.

[0023] like Figure 1 , Figure 2 As shown, the high-resolution benchtop X-ray spectrometer 100 includes: a sample signal source 1, an exponential crystal 2, and a detector 3.

[0024] See Figure 1 , Figure 2 Sample signal source 1 is located in the Doloran circle ( Figure 2 The area inside the dashed circle shown is used to generate X-rays. These X-rays can be polychromatic X-rays. When testing a sample, the X-rays are absorbed by the sample and carry the sample's absorption information before being incident on the index crystal 2. Polychromatic X-rays refer to X-rays that contain a continuous wavelength range (also known as "white light" X-rays).

[0025] Exponential crystal 2 is a curved crystal whose surface shape is defined by the exponential equation, resulting in different points on the crystal surface having different radii of curvature and corresponding Rowland circles of different radii. Each point on exponential crystal 2 is tangent to its corresponding Rowland circle. Exponential crystal 2 is used to monochromate and focus X-rays incident from sample signal source 1. Monochromatic X-rays obtained after monochromatization refer to X-rays with a single specific wavelength (or energy), typically generated through screening using a monochromator (composed of crystals). Curved crystals are single-crystal materials (such as silicon, germanium, or quartz) whose lattice surfaces are uniformly curved through mechanical force or special processing. Ordinary flat crystals can only reflect parallel light that satisfies Bragg's equation, while curved crystals have focusing or splitting capabilities. Like a lens focusing visible light, it can focus a diverging X-ray beam to a point or a line, greatly improving the signal intensity of X-ray experiments.

[0026] Detector 3 is located on the plane formed by the corresponding imaging points on each Rowland circle. It receives X-rays after monochromatization and focusing by exponential crystal 2 and outputs the corresponding light intensity signal. A Rowland circle is a geometric concept in spectroscopic instrument design, defined as a circle with radius R. If a concave diffraction grating (or crystal) with a curvature radius of 2R is placed on the circumference, then the entrance slit, the grating center, and the focal line of the diffracted light will all fall on the same circumference. This geometric arrangement ensures that light of different wavelengths, after being diffracted by the grating, can be precisely focused at different positions on the circumference, thus achieving high-resolution spectral analysis.

[0027] For example, the exponential equation is Where R(s) represents the radius of curvature at different locations on the surface of exponential crystal 2. Let be the initial radius of curvature, k be the exponential variation coefficient, and s be the position coordinates along the surface of exponential crystal 2. The values ​​of and k can be determined through ray tracing optimization based on the energy range of the X-rays to be measured, the distance between the sample signal source 1 and the exponential crystal 2, and the physical dimensions of the exponential crystal 2. Through the surface defined by this exponential equation, different points on the crystal have continuously varying radii of curvature, allowing each point to be matched with Rowland circles of different radii, thus achieving multi-Roland circle focusing.

[0028] Taking the testing requirements for the K-edge of sulfur (approximately 2.5 keV) as an example, the exponential crystal 2 uses a silicon (111) crystal plane with a plane spacing of d = 0.3135 nm. The radius of curvature at the crystal center point is... =250mm, exponential variation coefficient k= The crystal has a length of 50 mm along the sagittal direction. Through this design, the radius of curvature corresponding to different points on the crystal varies continuously within the range of 250 mm to 300 mm, matching Rowland circles of different radii, thus achieving efficient monochromaticization and focusing in the energy range of 2.3 keV to 2.7 keV.

[0029] In the Doroland circle structure, the number of Rowland circles is determined by the continuous set of points on the surface of the exponential crystal 2, with each point on the crystal corresponding to one Rowland circle. See also Figure 2 The sample signal source 1 is located inside the Doroland circle. Points Ci (i=1,2,3…) on the exponential crystal 2 are tangent to the Doroland circle Pi. The Doroland circle Pi is established with the radius of curvature ri as its diameter. The detector 3 is located on the surface formed by point Ii on the Doroland circle Pi. Based on the principle of ray optics, all rays emanating from point S to this circle converge at point Ii according to the principle of rotational symmetry, and have the same Bragg angle θi.

[0030] In this embodiment, by employing the synergistic combination of the exponential crystal 2 and the Doroland circle structure, X-ray absorption spectroscopy testing with high light-gathering efficiency, high spectral resolution, and a wide energy range is achieved. Specifically, the surface shape of the exponential crystal 2 is defined by the exponential equation, and its asymmetric curvature distribution results in different points on the crystal surface having different radii of curvature. Each point is tangent to the corresponding radius of the Doroland circle, which suppresses the influence of light source size expansion on spectral resolution and enables precise point source imaging on larger crystal shapes, while exhibiting extremely high spectral resolution. Simultaneously, the Doroland circle structure eliminates the John von Neumann error, minimizing the impact of light source size on spectral resolution. This structure also possesses rotational symmetry, enabling aberration-free, high-efficiency spectral focusing. Therefore, theoretically, it can detect a wide spectral range and obtain high-intensity X-ray signals with optimal spectral resolution.

[0031] Therefore, the high-resolution benchtop X-ray spectrometer 100 can achieve X-ray absorption spectroscopy testing at near-synchrotron radiation levels in a laboratory environment, meeting the urgent needs of materials science, catalytic chemistry, energy devices and other fields for efficient and high-resolution X-ray absorption spectroscopy testing.

[0032] In some implementations, such as Figure 3 As shown, the sample signal source 1 includes an X-ray tube 101 and a sample carrier 102.

[0033] See Figure 3The X-ray tube 101 and the sample carrier 102 are integrated, and the sample carrier 102 is located in front of the exit point of the X-ray tube 101 for placing the sample. The X-rays generated by the X-ray tube 101 are absorbed by the sample and then irradiate the exponential crystal 2.

[0034] Specifically, the X-ray tube 101 can use tungsten or palladium as the target material, and a sample carrier 102 for placing the sample is mounted facing the X-ray emission direction. The polychromatic X-rays emitted from the X-ray tube 101 are attenuated by the sample on the sample carrier 102, and the emitted X-rays carry the absorption information of the sample, providing a reliable signal source for subsequent monochromatization and focusing. The sample carrier 102 is positioned in front of the emission point of the X-ray tube 101, allowing the X-rays to irradiate the sample with the shortest path, reducing energy loss in the optical path. Simultaneously, the sample carrier 102 can be adaptively configured according to the sample type (e.g., solid, powder, liquid), improving the spectrometer's applicability and flexibility. Furthermore, this compact structure is compatible with the positional requirements of the sample signal source 1 in the Doroland circle configuration, ensuring the geometric consistency of the overall optical path and laying the foundation for achieving high-resolution, high-collection-efficiency X-ray absorption spectroscopy testing.

[0035] For example, the sample carrier 102 is a detachable sample stage suitable for fixing solid samples; the sample carrier 102 can also be a sample cell with a transmission window, suitable for encapsulation testing of liquid or powder samples. The position of the sample carrier 102 in the X-ray optical path can be finely adjusted along the optical axis to optimize the incident angle and spot size of the X-rays.

[0036] In other embodiments, the sample signal source 1 includes an X-ray tube 101 and a sample carrier 102, which are separately disposed.

[0037] For example, the sample carrier 102 is positioned between the exponent crystal 2 and the detector 3. Specifically, along the X-ray path, the X-ray tube 101 is located at the upstream end, the exponent crystal 2 is positioned in the output light path of the X-ray tube 101, the sample carrier 102 is positioned in the output light path of the exponent crystal 2, and the detector 3 is positioned in the output light path of the sample carrier 102. The polychromatic X-rays generated by the X-ray tube 101 are first monochromated into monochromatic X-rays by the exponent crystal 2. The monochromatic X-rays irradiate the sample on the sample carrier 102, and the X-rays absorbed by the sample are received by the detector 3.

[0038] For example, the sample carrier 102 is positioned at the front end of the detector 3 and located in the focusing optical path of the exponential crystal 2. Specifically, the exponential crystal 2 monochromates and focuses X-rays onto the sample carrier 102, and the X-rays absorbed by the sample are received by the detector 3. This arrangement is suitable for testing trace samples, and by placing the sample at the focused spot, it improves the utilization efficiency of X-rays and the detection sensitivity.

[0039] The two layouts described above are suitable for different testing scenarios. The integrated setup (X-ray tube and sample carrier integrated) is suitable for conventional X-ray absorption spectroscopy testing, offering advantages such as compact structure and stable optical path. The separate setup (e.g., sample carrier 102 located between exponential crystal 2 and detector 3) is suitable for fluorescence mode X-ray absorption spectroscopy testing or applications where the sample is sensitive to radiation. By monochromating before absorption, it can reduce radiation damage to the sample and improve energy resolution.

[0040] Furthermore, by placing the sample carrier 102 on the focusing optical path of the exponential crystal 2, X-rays can be focused onto the sample surface, significantly increasing the X-ray flux per unit area. This is suitable for the analysis and testing of trace samples or low-concentration elements, and improves the detection sensitivity and signal-to-noise ratio of the spectrometer.

[0041] In some embodiments, the radius of curvature of the exponential crystal 2 on the meridional plane is greater than the radius of curvature on the sagittal plane, forming an asymmetric curvature distribution.

[0042] The meridional plane refers to the plane containing the incident X-ray principal ray and the normal to the surface of exponential crystal 2. The radius of curvature on the meridional plane is the radius of curvature of exponential crystal 2 within this plane, determining the focusing and monochromatic characteristics of X-rays within the optical path plane. The sagittal plane refers to the plane perpendicular to both the meridional plane and the tangent to the surface of exponential crystal 2. The radius of curvature on the sagittal plane is the radius of curvature of exponential crystal 2 within this plane, determining the focusing characteristics of X-rays in the direction perpendicular to the optical path plane, used to suppress astigmatism and the influence of light source size extension on spectral resolution.

[0043] Through this asymmetric curvature design, different points on the surface of the exponential crystal 2 have different radii of curvature, and each point corresponds to a Rowland circle with a different radius. Each point on the exponential crystal 2 is tangent to its corresponding Rowland circle, thus achieving precise matching of the multi-Roland circle structure. This design eliminates the defects commonly found in traditional curved crystals (such as planar, cylindrical, conical, and spherical crystals), such as low photon collection efficiency, lack of Rowland circle structure, astigmatism caused by paraxial approximation, and John error. Furthermore, it enables precise point source imaging on larger crystal shapes, effectively suppressing the influence of light source size on spectral resolution while exhibiting extremely high spectral resolution.

[0044] In some examples, exponential crystal 2 uses a low-index crystal plane.

[0045] Specifically, low-index crystal planes refer to crystal planes with small Miller indices (h, k, l), such as (100), (110), and (111). For example, when the material of index crystal 2 is single-crystal silicon, the Si (111) crystal plane can be used; when the material is single-crystal germanium, the Ge (111) crystal plane can be used; and when the material is quartz, the quartz (101) crystal plane can be used. These low-index crystal planes have a higher atomic surface density and a more compact atomic arrangement.

[0046] By employing a low-index crystal plane, the diffraction intensity of index crystal 2 is significantly enhanced. This is because the low-index crystal plane has a larger structure factor, and the combined diffraction efficiency under the combined effects of the atomic scattering factor and temperature factor is higher than that of the high-index crystal plane. Specifically, under the same incident X-ray flux conditions, the intensity of diffracted X-rays produced by the low-index crystal plane can be several times to an order of magnitude higher than that of the high-index crystal plane, thereby improving the signal-to-noise ratio of detector 3 and the detection sensitivity of the spectrometer.

[0047] In other examples, exponential crystal 2 employs a high-index crystal plane.

[0048] Specifically, high-index crystal planes refer to crystal planes with large values ​​of crystal plane indices h, k, and l, such as (311), (331), and (511). For example, when the material of index crystal 2 is single-crystal silicon, the Si (311) crystal plane can be used; when the material is single-crystal germanium, the Ge (331) crystal plane can be used. These high-index crystal planes have a small atomic surface density and a large interplanar spacing, which can meet the diffraction requirements of higher-energy X-rays.

[0049] By employing high-index crystal planes, the exponential crystal 2 can cover a wider range of X-ray energies. Due to the smaller interplanar spacing of high-index crystal planes, according to Bragg's equations (the mathematical conditions describing X-ray diffraction in crystals, which stipulate that enhanced diffraction signals can only be observed when the optical path difference is an integer multiple of the wavelength), higher-energy X-rays can be diffracted within the same Bragg angle variation range. Therefore, high-index crystal planes are suitable for testing the absorption edges of high atomic number elements (such as the K edge of Cu (approximately 8.9 keV) and the L edge of Pt (approximately 11.5 keV), expanding the application range of the spectrometer.

[0050] In some implementations, such as Figure 4 As shown, the detector 3 includes a detector body 301 and a CMOS (Complementary Metal Oxide Semiconductor) photosensitive element 302.

[0051] See Figure 4The CMOS photosensitive element 302 is disposed at the front end of the detector body 301. It is used to receive X-rays after monochromatization and focusing by the exponential crystal 2, and convert the received X-ray signal into an electrical signal and transmit it to the detector body 301 so that the detector body 301 outputs a light intensity signal characterizing the intensity of X-rays.

[0052] Specifically, by placing the CMOS photosensitive element 302 at the front end of the detector body 301, it can directly receive X-rays after monochromatization and focusing by the exponential crystal 2, effectively shortening the signal transmission path and reducing signal attenuation and noise introduction. The CMOS photosensitive element 302 converts X-ray photons into electrical signals, which has the advantages of fast response speed, high sensitivity, and wide dynamic range, and can accurately capture weak X-ray signals, ensuring the signal-to-noise ratio of the spectral data.

[0053] After receiving the electrical signal transmitted by the CMOS photosensitive element 302, the detector body 301 can amplify, read out, and process the signal, outputting a light intensity signal characterizing the X-ray intensity. This light intensity signal has a linear relationship with the intensity of the incident X-rays, providing accurate basic data for subsequent absorption coefficient calculation and XAFS data analysis. Furthermore, the CMOS photosensitive element 302 is matched to the position requirements of the detector 3 in the Doroland circle structure, ensuring that the detector 3 is located on the plane formed by the corresponding imaging points on each Doroland circle, thereby achieving accurate signal reception and high-quality imaging.

[0054] For example, the CMOS photosensitive element 302 can be a high-sensitivity back-illuminated CMOS image sensor, characterized by high quantum efficiency and low readout noise, which can effectively improve the detection efficiency of X-rays. The pixel array of the CMOS photosensitive element 302 is matched with the size of the X-ray spot after being focused by the exponential crystal 2, ensuring that all signals within the spot coverage area can be effectively acquired.

[0055] In some embodiments of the present invention, the high-resolution benchtop X-ray spectrometer 100 further includes a controller.

[0056] The controller is connected to the sample signal source 1, the detector 3 and the exponential crystal 2 respectively, and is used to adjust the distance between the sample signal source 1 and the detector 3, and / or adjust the crystal plane of the exponential crystal 2 according to the test requirements to obtain data in different energy ranges.

[0057] Specifically, the controller can be connected to the X-ray tube 101 in the sample signal source 1 via a drive circuit to control the opening and closing of the X-ray tube 101 and its operating voltage and current; the controller can be connected to the sample signal source 1 and the detector 3 via a precision displacement control mechanism to adjust the relative distance between the sample signal source 1 and the detector 3; the controller can be connected to the index crystal 2 via an angle control mechanism to adjust the crystal orientation of the index crystal 2 or replace crystals with different crystal indexes.

[0058] Specifically, regarding distance adjustment, when testing lower-energy X-rays (such as the K-edge of light elements), the controller controls the drive mechanism to shorten the distance between the sample signal source 1 and the detector 3 to enhance the light collection efficiency of low-energy X-rays. When testing higher-energy X-rays (such as the K-edge of heavy elements), the controller controls the drive mechanism to increase the distance between the sample signal source 1 and the detector 3 to meet the focusing geometry requirements of high-energy X-rays. This distance adjustment can be achieved by a stepper motor driving a precision lead screw mechanism, with control accuracy down to the micrometer level, ensuring precise matching of the optical path geometry.

[0059] For crystal plane adjustment, when testing the K-edge absorption spectrum of light elements (such as sulfur, phosphorus, silicon, etc.), the controller controls the crystal switching mechanism to switch the exponent crystal 2 to a low-index crystal plane (such as Si(111), Ge(111) etc.) to obtain higher diffraction intensity and signal-to-noise ratio; when testing the K-edge or L-edge absorption spectrum of heavy elements (such as copper, platinum, gold, etc.), the controller controls the crystal switching mechanism to switch the exponent crystal 2 to a high-index crystal plane (such as Si(311), Ge(331) etc.) to meet the diffraction requirements of high-energy X-rays. The crystal switching mechanism can adopt a rotary or sliding rail design, with multiple crystals of different crystal plane indices built in. The controller automatically selects and switches to the corresponding crystal according to the test energy range input by the user.

[0060] For comprehensive adjustments to distance and crystal plane, for example, when testing the K-edge of sulfur (approximately 2.5 keV), the controller automatically adjusts the distance between sample signal source 1 and detector 3 to a preset 250 mm and switches the exponential crystal 2 to a low-index Si(111) crystal plane; when testing the K-edge of copper (approximately 8.9 keV), the controller automatically adjusts the distance between sample signal source 1 and detector 3 to a preset 320 mm and switches the exponential crystal 2 to a high-index Si(311) crystal plane. Through these coordinated adjustments, optimal spectral resolution and light collection efficiency are ensured across different energy ranges.

[0061] For example, the controller can also integrate data acquisition and processing functions. Specifically, after completing the distance and crystal plane adjustment, the controller automatically starts the X-ray tube 101, acquires the first light intensity signal (with sample) and the second light intensity signal (without sample) output by the detector 3, and calculates the absorption coefficient according to the preset algorithm to generate X-ray absorption spectrum data.

[0062] Therefore, a fully automated testing process can improve testing efficiency and reduce human error.

[0063] Example 2: X-ray absorption spectroscopy testing method In this embodiment, the X-ray absorption spectroscopy testing method is used in the high-resolution benchtop X-ray spectrometer 100 of the above embodiment 1. The sample signal source 1 in the high-resolution benchtop X-ray spectrometer 100 includes an X-ray tube 101 and a sample carrier 102, with the sample carrier 102 disposed in front of the exit point of the X-ray tube 101.

[0064] like Figure 5 As shown, the X-ray absorption spectroscopy testing method includes the following steps: S11, in response to the sample carrier holding a sample, turns on the X-ray tube so that the polychromatic X-rays generated by the X-ray tube irradiate the sample and are attenuated by the sample before being incident on the exponential crystal, and acquires the first light intensity signal output by the detector corresponding to the X-rays after monochromatization and focusing by the exponential crystal.

[0065] S12, in response to the absence of a sample on the sample carrier, turns on the X-ray tube, allowing the polychromatic X-rays generated by the X-ray tube to be incident on the exponential crystal, and acquires the second light intensity signal output by the detector, corresponding to the X-rays after monochromatization and focusing by the exponential crystal.

[0066] S13. Based on the first light intensity signal and the second light intensity signal, obtain the X-ray absorption spectrum data.

[0067] Specifically, the X-ray absorption spectroscopy test is performed using the high-resolution benchtop X-ray spectrometer 100 described in the above embodiment. First, the prepared sample is properly placed on the sample carrier 102. After the high voltage of the X-ray tube 101 is turned on, the polychromatic X-rays generated by the X-ray tube 101 irradiate the sample carrier 102 and are absorbed by the sample. The absorbed and attenuated X-rays are then diffracted into monochromatic X-rays by the exponential crystal 2 and focused before being received by the detector 3, yielding a first intensity signal P1. Subsequently, the sample is removed from the sample carrier 102, and under the same test conditions, the X-ray intensity on the sample carrier 102 without the sample is measured, yielding a second intensity signal P0. The P1 and P0 data are then processed to obtain the XAFS data.

[0068] For example, the order of steps S11 and S12 can be interchanged.

[0069] In some embodiments of the present invention, X-ray absorption spectrum data is obtained based on a first light intensity signal and a second light intensity signal, including: calculating the absorption coefficient according to the formula μ(E)=ln(P0 / P1), where P0 is the second light intensity signal and P1 is the first light intensity signal; performing energy calibration, background subtraction and normalization processing on the absorption coefficient to obtain a normalized absorption spectrum; and extracting the XAFS oscillation function from the normalized absorption spectrum to obtain X-ray absorption spectrum data.

[0070] Figure 6 It shows the basis Figure 1 The K-side XAS image of the S element was obtained using a high-resolution benchtop X-ray spectrometer 100 (the distance between sample signal source 1 and exponential crystal 2 is 280 mm, the distance between exponential crystal 2 and detector 3 is 790 mm, and the Bragg angle is 36°).

[0071] In some embodiments of the present invention, before acquiring the first light intensity signal and the second light intensity signal, the method further includes: adjusting the distance between the sample signal source and the detector according to the energy range required for the test.

[0072] In some embodiments of the present invention, before acquiring the first light intensity signal and the second light intensity signal, the method further includes: adjusting the crystal plane of the exponential crystal according to the energy range required for the test.

[0073] It should be noted that for other specific embodiments of the X-ray absorption spectrum testing method of the present invention, please refer to the specific embodiments of the high-resolution benchtop X-ray spectrometer 100 in the above embodiments.

[0074] In summary, the high-resolution benchtop X-ray spectrometer and X-ray absorption spectroscopy testing method of the present invention can achieve the following beneficial effects: 1) By employing a unique exponential crystal design, the high-resolution benchtop X-ray spectrometer possesses the advantages of high light collection efficiency and high spectral resolution. The exponential crystal structure can suppress the influence of light source size expansion on spectral resolution. Through the asymmetric design of variable curvature radii on the meridional and sagittal planes, precise point source imaging can be achieved on larger crystal shapes, effectively suppressing the influence of light source size on spectral resolution while exhibiting extremely high spectral resolution. Compared with traditional curved crystals (such as planar, cylindrical, conical, and spherical crystals), this invention overcomes their common defects such as low photon collection efficiency, astigmatism caused by paraxial approximation, and John von Neumann error, significantly improving the overall performance of the spectrometer.

[0075] 2) By employing a unique Doroland circle structure design, the high-resolution benchtop X-ray spectrometer possesses advantages such as a wide spectral range, high light-gathering efficiency, and high spectral resolution. The Doroland circle structure eliminates the John Johann error caused by approximation in traditional single Doroland circle configurations by ensuring that each point on the exponential crystal is tangent to a Doroland circle of corresponding radius. Furthermore, its rotational symmetry enables aberration-free, high-efficiency spectral focusing. Theoretically, this structure can detect a wide spectral range while obtaining high-intensity X-ray signals with optimal spectral resolution, making it suitable for testing a broad energy range from light to heavy elements and from soft to hard X-rays.

[0076] 3) By employing a Bragg angle design that satisfies X-ray diffraction, X-ray absorption spectroscopy testing of elements in a region can be achieved in a conventional laboratory without the need for a synchrotron radiation source. By precisely satisfying the Bragg diffraction conditions, combined with the synergistic effect of exponential crystals and Doroland circular structures, this invention can obtain spectral resolution and signal-to-noise ratio close to synchrotron radiation levels in a laboratory environment. It can investigate information such as valence state, electronic structure, local coordination environment, bond length, coordination number, and degree of structural disorder of materials within a specific energy range, providing an efficient and convenient X-ray absorption spectroscopy testing method for materials science, catalysis chemistry, energy devices, and other fields.

[0077] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0078] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] In the description of this invention, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0081] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0082] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-resolution benchtop X-ray spectrometer, characterized in that, include: Sample signal source, exponential crystal, and detector; The sample signal source is located inside the Dorothy circle and is used to generate X-rays; The exponential crystal is a curved crystal whose surface shape is defined by an exponential equation, such that different points on the crystal surface have different radii of curvature and correspond to Rowland circles of different radii. Each point on the exponential crystal is tangent to the corresponding Rowland circle. The exponential crystal is used to monochromate and focus the X-rays incident from the sample signal source. The detector is located on the surface formed by the corresponding imaging points on each Rowland circle, and is used to receive X-rays that have been monochromated and focused by the exponential crystal, and output the corresponding light intensity signal.

2. The high-resolution benchtop X-ray spectrometer according to claim 1, characterized in that, The sample signal source includes an X-ray tube and a sample carrier: The sample carrier is positioned in front of the exit point of the X-ray tube and is used to place the sample. The X-rays generated by the X-ray tube are absorbed by the sample and then irradiate the index crystal.

3. The high-resolution benchtop X-ray spectrometer according to claim 1, characterized in that, The exponential crystal has a larger radius of curvature on the meridional plane than on the sagittal plane, forming an asymmetric curvature distribution.

4. The high-resolution benchtop X-ray spectrometer according to claim 1, characterized in that, The indexed crystal uses a low-index crystal plane.

5. The high-resolution benchtop X-ray spectrometer according to claim 1, characterized in that, The detector includes a detector body and a CMOS photosensitive element; The CMOS photosensitive element is disposed at the front end of the detector body and is used to receive X-rays after monochromatization and focusing by the exponential crystal, and convert the received X-ray signal into an electrical signal and transmit it to the detector body so that the detector body outputs a light intensity signal characterizing the intensity of X-rays.

6. The high-resolution benchtop X-ray spectrometer according to claim 1, characterized in that, The high-resolution benchtop X-ray spectrometer also includes: The controller is connected to the sample signal source, the detector, and the exponential crystal, respectively, and is used to adjust the distance between the sample signal source and the detector, and / or adjust the crystal facets of the exponential crystal according to the test requirements, so as to obtain data in different energy ranges.

7. A method for X-ray absorption spectroscopy testing, characterized in that, For a high-resolution benchtop X-ray spectrometer as described in any one of claims 1 to 6, the sample signal source in the high-resolution benchtop X-ray spectrometer includes an X-ray tube and a sample carrier, the sample carrier being disposed in front of the exit point of the X-ray tube, the method comprising the following steps: In response to the sample carrier having a sample placed on it, the X-ray tube is turned on, so that the polychromatic X-rays generated by the X-ray tube irradiate the sample, and after being absorbed and attenuated by the sample, they are incident on the exponential crystal, and the first light intensity signal output by the detector corresponding to the X-rays after being monochromated and focused by the exponential crystal is acquired. In response to the absence of a sample on the sample carrier, the X-ray tube is turned on, allowing the polychromatic X-rays generated by the X-ray tube to be incident on the exponential crystal, and the second light intensity signal output by the detector, corresponding to the X-rays after monochromatization and focusing by the exponential crystal, is acquired; X-ray absorption spectrum data are obtained based on the first light intensity signal and the second light intensity signal.

8. The X-ray absorption spectroscopy testing method according to claim 7, characterized in that, The step of obtaining X-ray absorption spectrum data based on the first light intensity signal and the second light intensity signal includes: The absorption coefficient is calculated according to the formula μ(E)=ln(P0 / P1), where P0 is the second light intensity signal, P1 is the first light intensity signal, and μ(E) is the absorption coefficient. The absorption coefficient is subjected to energy calibration, background subtraction and normalization to obtain the normalized absorption spectrum; The XAFS oscillation function is extracted from the normalized absorption spectrum to obtain the X-ray absorption spectrum data.

9. The X-ray absorption spectroscopy testing method according to claim 7, characterized in that, Before acquiring the first light intensity signal and the second light intensity signal, the method further includes: Adjust the distance between the sample signal source and the detector according to the energy range required for the test.

10. The X-ray absorption spectroscopy testing method according to claim 7, characterized in that, Before acquiring the first light intensity signal and the second light intensity signal, the method further includes: The crystal planes of the exponential crystal are adjusted according to the energy range required for the test.

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