Wide-energy-region in-situ X-ray spectroscopy characterization system

Abstract

The invention relates to a wide-energy-region in-situ X-ray spectroscopy characterization system, which comprises a first undulator and a second undulator, and is characterized in that the first undulator is used for providing hard X-ray light and forming a first light path through which a hard X-ray beam passes, and the second undulator is used for providing soft X-ray light and forming a second light path through which a soft X-ray beam passes; a first deflection focusing device and a first Si3N4 film window are sequentially arranged on the first light path along the transmission direction of the hard X light beam; on the second light path, a second deflection focusing device and a second Si3N4 film window are sequentially arranged along the transmission direction of the soft X light beam; when the hard X beam passes through the first Si3N4 film window after being deflected and focused by the first deflection focusing device, the soft X beam passes through the second Si3N4 film window after being deflected and focused by the second deflection focusing device and irradiates a sample together, and an amplifier is arranged at the downstream of the sample to amplify a light current signal so as to obtain in-situ characterization information of the sample. According to the invention, ultra-wide energy range photon coverage can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of synchrotron radiation X-ray spectroscopy in-situ measurement, and more particularly to an in-situ X-ray spectroscopy characterization system for a wide energy range. Background Art

[0002] X-ray spectroscopy excites electrons in occupied orbitals to the vacuum energy level or conduction band energy level, thereby obtaining fingerprint information such as the atomic and electronic orbitals of the element being measured. This information is used to analyze the valence state, energy level structure, coordination bond type and length, and the type and number of coordinated atoms in the core atoms of functional materials. Therefore, X-ray spectroscopy possesses both elemental and chemical valence state sensitivity, making it a widely used characterization method in disciplines such as physics, chemistry, and materials science.

[0003] Currently, X-ray spectroscopy based on synchrotron radiation or laboratory X-ray sources at home and abroad suffers from photon energy discontinuity, particularly in the mid-energy region (1500-3000 eV), where characterization methods are lacking and in-situ characterization of mid-energy spectra is difficult. For example, laboratory X-ray spectroscopy characterization platforms primarily utilize the intrinsic Kα fluorescence of Mg / Al / Cr / Ga targets (1254 eV / 1486 eV / 5415 eV / 9251 eV) for X-ray photoelectron spectroscopy experiments, and the Kα characteristic fluorescence and bremsstrahlung of W / Mo / Ag targets for X-ray absorption spectroscopy experiments. In other words, synchrotron radiation-based X-ray spectroscopy at home and abroad is basically based on X-rays in a specific energy range, either soft X-ray spectroscopy (100 eV-1500 eV) or hard X-ray spectroscopy (above 3000 eV). There are very few X-ray spectroscopy covering a wide energy range from lithium to polonium (period 2 to period 6) in the periodic table, especially covering important elements in the fields of energy materials, environment and life sciences such as Si / P / S / Cl (1839 eV / 2146 eV / 2472 eV / 2822 eV).

[0004] To achieve in situ X-ray spectroscopy across an ultra-wide energy range, only the BESSY experimental station in Germany can currently perform X-ray spectroscopy within the photon energy range of 80 eV-10,000 eV. However, its upper photon energy limit is only 10,000 eV, which cannot cover precious metal elements such as Pt and Ir. Furthermore, its in situ spectroscopy testing scheme involves filling the sample reaction / test chamber with reactive gas and introducing a three-stage differential pumping system between the ultra-high vacuum X-ray path and the high-pressure test chamber to minimize contamination of the ultra-high vacuum environment of the X-ray path by the in situ reaction / test atmosphere. However, as the test environment changes and test time accumulates, contamination of the X-ray path, including the X-ray reflectors and X-ray focusing mirrors, by the reactive gas becomes increasingly severe, making in situ X-ray spectroscopy of solid-liquid systems difficult to achieve. Summary of the Invention

[0005] To solve the above problems in the prior art, the present invention provides an in-situ X-ray spectroscopy characterization system with a wide energy range, which can achieve photon coverage in an ultra-wide energy range of 1500eV~22000eV.

[0006] The present invention provides an in-situ X-ray spectroscopy characterization system for a wide energy range, comprising a first undulator and a second undulator, wherein the first undulator is used to provide hard X-ray light to form a first optical path through which the hard X-ray beam passes, and the second undulator is used to provide soft X-ray light to form a second optical path through which the soft X-ray beam passes; on the first optical path, a first deflection and focusing device and a first Si3N4 film window are sequentially arranged along the transmission direction of the hard X-ray beam; on the second optical path, a second deflection and focusing device and a second Si3N4 film window are sequentially arranged along the transmission direction of the soft X-ray beam; while the hard X-ray beam passes through the first Si3N4 film window after being deflected and focused by the first deflection and focusing device, the soft X-ray beam passes through the second Si3N4 film window after being deflected and focused by the second deflection and focusing device, and the hard X-ray beam and the soft X-ray beam simultaneously pass through the corresponding first Si3N4 film window and second Si3N4 film window and are jointly irradiated onto a sample, and an amplifier is provided downstream of the sample to amplify the photocurrent signal to obtain in-situ characterization information of the sample.

[0007] Furthermore, the first undulator adopts an in-vacuum undulator to provide photons in the energy range of 1500eV~22000eV; the second undulator adopts an elliptically polarized undulator to provide photons in the energy range of 130eV~1500eV.

[0008] Furthermore, the period length of each magnet in the vacuum undulator is 24 mm, the number of periods is 65, and the total length is 1.56 m; and the peak magnetic field of the vacuum undulator is 0.96 T, and the minimum spacing between the north and south poles of the magnet is 6 mm.

[0009] Furthermore, the first deflection and focusing device and the second deflection and focusing device include a toroidal cylindrical focusing mirror and a matching motion adjustment mechanism.

[0010] Furthermore, the distance between the first Si3N4 membrane window and the second Si3N4 membrane window is 58 mm.

[0011] Furthermore, the diameter of the first Si3N4 membrane window and the second Si3N4 membrane window is 5 mm and the thickness is 100 nm.

[0012] Furthermore, the first Si3N4 membrane window and the second Si3N4 membrane window are packaged on a vacuum flange, and the vacuum flange is installed at the front end of the reaction test chamber.

[0013] Furthermore, the vacuum flange is installed at 0.5 m from the front end of the reaction test chamber.

[0014] Furthermore, the first Si3N4 film window is perpendicular to the propagation direction of the hard X-ray beam, and the second Si3N4 film window is perpendicular to the propagation direction of the soft X-ray beam.

[0015] Furthermore, a fluorescent target is provided at the sample.

[0016] The present invention has the following beneficial effects:

[0017] 1) By optimizing the magnet spacing and magnetic field peak of the vacuum undulator, a maximum photon energy of 22,000 eV was achieved;

[0018] 2) The ingenious design of a dual Si3N4 film window reduces the overall area of ​​the Si3N4 window film and increases the window film's ability to withstand pressure differentials and reaction gas pressures: the two independent Si3N4 window films are responsible for physically isolating the vacuum environment of soft and hard X-rays from the high-pressure environment of the in-situ reaction / test chamber, while ensuring the normal passage of X-rays. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the wide energy range in-situ X-ray spectroscopy characterization system according to the present invention.

[0020] Figure 2 yes Figure 1 Schematic diagram of the photon flux output of a medium-vacuum undulator.

[0021] Figure 3 (a) is the X-ray core state spectrum of Au(111) single crystal under 41 mbar Ar2 gas; Figure 3 (b) is the L3 edge X-ray absorption spectrum of Ru single crystal under 1 mbar.

[0022] Figure 4 (a) is the L3 edge absorption spectrum of Pr measured in the energy range of 5900eV~6300eV in 1mbar O2 atmosphere; Figure 4 (b) is the L3 edge absorption spectrum of Au in the energy range of 11000eV~12000eV. DETAILED DESCRIPTION

[0023] In order to make the purpose, scheme and advantages of the present invention clearer, the specific structure and working principle of the present invention are described in more detail below with reference to the accompanying drawings. The embodiments mentioned are only used to explain the present invention and are not limited to the embodiments and are not used to limit the scope of application of the present invention.

[0024] The following content is intended to enable the public to have a clearer understanding of the present invention. For those skilled in the art working in the relevant field, the present invention can be clearly understood even without the following detailed description.

[0025] like Figure 1 As shown, the present invention provides an in-situ X-ray spectroscopy characterization system for a wide energy range, comprising a first undulator 10 and a second undulator 20. The first undulator 10 is used to provide hard X-ray light to form a first optical path through which the hard X-ray beam passes; the second undulator 20 is used to provide soft X-ray light to form a second optical path through which the soft X-ray beam passes.

[0026] The first undulator 10 and the second undulator 20 are independently provided, so that the hard X-ray beam and the soft X-ray beam are two independent optical paths. In this embodiment, the first undulator 10 is an in-vacuum undulator, which can provide photons with a continuously adjustable energy range of 1500eV to 22000eV. Figure 2 As shown, the second undulator 20 uses an elliptically polarized undulator, providing continuously tunable photons in the energy range of 130 eV to 1500 eV. The period length of each magnet in the in-vacuum undulator is 24 mm, the number of periods is 65, and the total length is 1.56 m. The peak magnetic field of the in-vacuum undulator is 0.96 T, and the minimum spacing between the north and south poles of the magnets is 6 mm.

[0027] On the first optical path, a first deflection and focusing device 11 and a first Si3N4 film window 12 are sequentially arranged along the transmission direction of the hard X-ray beam; on the second optical path, a second deflection and focusing device 21 and a second Si3N4 film window 22 are sequentially arranged along the transmission direction of the soft X-ray beam.

[0028] In this embodiment, the two deflection and focusing devices 11 and 21 are independently configured and identical, comprising a toroidal cylindrical focusing mirror and a matching motion adjustment mechanism. They are used to deflect and focus the hard and soft X-ray beams, respectively, so that the two deflected and focused X-ray beams converge at the same location on the sample 3. This design ensures 100% overlap between the two X-ray beams. Therefore, at the same location on the sample, full coverage of X-rays in the energy range of 130 eV to 22,000 eV is achieved.

[0029] Since one side of the Si3N4 film window is in ultra-high vacuum environment (10 -9 mbar), and the other side is a near-normal pressure reaction environment (100mbar). In order to increase the pressure difference resistance of the Si3N4 membrane window, the thickness of the membrane needs to be increased. In order to increase the penetration ability of X-rays in the low-energy region (130eV-1500eV), the membrane cannot be too thick. At the same time, at the same thickness, the larger the area of ​​the membrane window, the smaller its pressure difference resistance, and the easier it is to be damaged. Based on the above considerations, the present invention adopts a double Si3N4 membrane window design. The spacing between the two Si3N4 membrane windows is 58mm±5mm, the diameter of each Si3N4 membrane window is 5mm±1mm, and the thickness is 100nm. The Si3N4 window film with a thickness of 100nm can ensure that more than 50% of soft X-rays are transmitted. In this way, the design of a large Si3N4 membrane window can be avoided, the area of ​​the membrane window is effectively reduced, and the pressure difference on both sides of the membrane window is guaranteed. If a whole Si3N4 film window is used, considering that two independent X-ray beams of 130-1500eV and 1500-22000eV need to pass through at the same time and the distance between the two beams, a Si3N4 film window with a diameter of 68mm needs to be designed, and its pressure resistance will be greatly reduced.

[0030] Furthermore, the first and second Si3N4 membrane windows 12, 22 are enclosed in a vacuum flange with holes cut into its sides. This vacuum flange, housing the two Si3N4 membrane windows, is mounted 0.5m from the front of the reaction test chamber. This 0.5m distance before the X-rays enter the reaction test chamber ensures uniform pressure in the reaction gas within the chamber and the proper installation of other optoelectronic components. Furthermore, the first Si3N4 membrane window 12 is perpendicular to the propagation direction of the hard X-ray beam, while the second Si3N4 membrane window 22 is perpendicular to the propagation direction of the soft X-ray beam, effectively increasing the X-ray flux after passing through the SiN window films.

[0031] With this design, the hard X-ray beam, after being deflected and focused by the first deflection and focusing device 11, passes through the first Si3N4 film window 12, while the soft X-ray beam, after being deflected and focused by the second deflection and focusing device 21, passes through the second Si3N4 film window 22. Both the hard and soft X-ray beams simultaneously pass through their respective film windows and irradiate the sample 3 under reaction conditions. A fluorescent target is placed at the sample 3 to monitor in real time whether the two X-ray beams independently pass through the film windows and reach the sample.

[0032] An amplifier 4 is provided downstream of the sample 3. By measuring the total photocurrent signal (referred to as the total electron yield) generated by the sample under X-ray irradiation and performing low-noise amplification, a high-quality X-ray absorption spectrum can be obtained, thereby obtaining the intrinsic elemental information and chemical valence state information of the sample.

[0033] The maximum gas pressure in the reaction test chamber can reach 100 mbar. Regardless of whether the sample is in a solid-gas environment or a solid-liquid environment, X-ray spectroscopy measurements can be performed under in-situ reaction conditions, effectively solving the characterization problems of wide-energy X-ray spectroscopy, especially the bottleneck of the lack of in-situ characterization of medium-energy X-ray spectroscopy.

[0034] The present invention achieves in-situ characterization of X-ray spectroscopy in an ultra-wide energy range, with photon energies ranging from 130 eV to 22,000 eV, especially in the energy range of 1,500 to 3,000 eV. As shown in Figure 3 (a), based on Au (111) single crystal, the Au4f core state peak is measured using soft X-rays. The shape, half-width, and peak area of ​​the spin-orbit splitting peaks of 4f5 / 2 and 4f7 / 2 are consistent with the experimental results under ultra-high vacuum conditions under 41 mbar Ar2 atmosphere, confirming the feasibility of the double-hole Si3N4 window film design and the robustness of the window film. As shown in Figure 3 (b), the Ru L3 edge X-ray absorption spectrum is measured in a 1 mbar CO2 reaction atmosphere using X-rays in the energy range of 2,820 to 2,870 eV. A clear oxidation peak appears on the right side, identifying the oxidation process of Ru during CO2 reduction, verifying the reliability and applicability of mid-energy spectroscopy.

[0035] Furthermore, as shown in Figures 4(a) and 4(b), the L3-edge absorption spectrum of the rare earth metal Pr was measured in situ using hard X-rays at 5900–6300 eV in a 1 mbar O2 atmosphere. A distinct oxidation component was detected, confirming the occurrence of an oxidation reaction. Absorption spectrum measurements of the L3 absorption edge of Au were performed in the 11900–12000 eV energy range, demonstrating that good X-ray absorption spectroscopy data can also be obtained using the full electron yield method in the hard X-ray energy range. These test data confirm the reliability and universality of in situ X-ray spectroscopy over a wide energy range.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Various modifications are possible. In other words, any simple, equivalent changes and modifications made in accordance with the claims and description of the present invention are within the scope of protection of the patent claims. Anything not fully described in this invention constitutes conventional technology.

Claims

1. A wide energy range in-situ X-ray spectroscopy characterization system, characterized in that: The invention comprises a first undulator and a second undulator, wherein the first undulator is used to provide hard X-ray light to form a first optical path through which the hard X-ray beam passes, and the second undulator is used to provide soft X-ray light to form a second optical path through which the soft X-ray beam passes; on the first optical path, a first deflection and focusing device and a first Si3N4 film window are sequentially arranged along the transmission direction of the hard X-ray beam; on the second optical path, a second deflection and focusing device and a second Si3N4 film window are sequentially arranged along the transmission direction of the soft X-ray beam; While the hard X-ray beam is deflected and focused by the first deflection and focusing device and passes through the first Si3N4 film window, the soft X-ray beam is deflected and focused by the second deflection and focusing device and passes through the second Si3N4 film window. The hard X-ray beam and the soft X-ray beam simultaneously pass through the corresponding first Si3N4 film window and the second Si3N4 film window and are jointly irradiated to the sample. An amplifier is provided downstream of the sample to amplify the photocurrent signal to obtain in-situ characterization information of the sample.

2. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 1, characterized in that: The first undulator adopts an in-vacuum undulator to provide photons in the energy range of 1500eV~22000eV; the second undulator adopts an elliptically polarized undulator to provide photons in the energy range of 130eV~1500eV.

3. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 2, characterized in that: The period length of each magnet in the vacuum undulator is 24 mm, the number of periods is 65, and the total length is 1.56 m; the peak magnetic field of the vacuum undulator is 0.96 T, and the minimum spacing between the north and south poles of the magnet is 6 mm.

4. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 1, characterized in that: The first deflection and focusing device and the second deflection and focusing device include a toroidal cylindrical focusing mirror and a matching motion adjustment mechanism.

5. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 1, characterized in that: The distance between the first Si3N4 film window and the second Si3N4 film window is 58 mm.

6. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 1, characterized in that: The diameter of the first Si3N4 film window and the second Si3N4 film window are 5 mm and the thickness is 100 nm.

7. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 1, characterized in that: The first Si3N4 membrane window and the second Si3N4 membrane window are packaged on a vacuum flange, and the vacuum flange is installed at the front end of the reaction test chamber.

8. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 7, characterized in that: The vacuum flange is installed 0.5m from the front end of the reaction test chamber.

9. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 1, characterized in that: The first Si3N4 film window is perpendicular to the propagation direction of the hard X-ray beam, and the second Si3N4 film window is perpendicular to the propagation direction of the soft X-ray beam.

10. The wide energy range in-situ X-ray spectroscopy characterization system according to claim 1, characterized in that: A fluorescent target is arranged at the sample.

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