A method for measuring the thermal load deformation of a synchrotron radiation spectrophotometer

Abstract

This invention relates to a method for measuring the thermal load deformation of a synchrotron radiation spectrometer, comprising: placing an orthogonal analytical crystal at the exit port of a monochromator; generating a diffracted beam by sequentially passing a first crystal, a second crystal, and the analytical crystal; incident the diffracted beam onto an imaging detector to obtain a Dumond diagram of the first crystal during thermal deformation; obtaining the emitted light intensity on the first crystal during thermal deformation based on the Dumond diagram; obtaining the emitted light intensity distribution at different detuning angles using X-ray simulation software; obtaining the detuning angle distribution at different positions on the first crystal surface based on the emitted light intensity distribution on the first crystal surface and the emitted light intensity distribution at different detuning angles; constructing a geometric model; and obtaining the thermal deformation distribution at different positions on the first crystal surface based on the geometric model and the detuning angle distribution at different positions on the first crystal surface, thereby realizing the measurement of the thermal load deformation of the synchrotron radiation spectrometer.

Description

Technical Field

[0001] This invention relates to the field of synchrotron radiation technology, to the performance testing of synchrotron radiation optical elements, and more specifically to a method for measuring the thermal load deformation of a synchrotron radiation spectroscopic crystal. Background Technology

[0002] The dual-crystal monochromator is a core instrument in synchrotron radiation beamlines, used to separate suitable monochromatic light from high-power synchrotron radiation for user experiments. On one hand, the monochromator is a precision X-ray optical instrument; on the other hand, it must withstand high-power synchrotron radiation. Therefore, its design and fabrication, especially the design of the crystal's thermal mitigation mechanism, present significant technical challenges. Current crystal cooling solutions are based on finite element method (FEM) simulations. These simulations calculate the heat load absorbed by each cell to simulate the temperature distribution on the crystal surface, taking into account material properties, the laws of thermal conduction, and set boundary conditions. This temperature distribution is then converted into thermal deformation of the crystal surface. However, FEM results are significantly affected by boundary conditions, and crystal clamping also introduces surface shape variations. Measuring the thermal deformation of the crystal under different radiation powers and operating conditions has long been a difficult problem, hindering a reasonable evaluation of the monochromator's thermal mitigation design.

[0003] The thermal deformation of a crystal can be indirectly obtained by measuring the temperature field distribution. However, common temperature sensors such as thermocouples and resistance temperature detectors (RTDs) fail in strong radiation environments or can only measure the temperature at certain points on the crystal, failing to provide information about the temperature field. While image-based radiation thermometers can measure the temperature distribution on the surface of general objects, single-crystal silicon is almost transparent in the infrared band, making it impossible to obtain reliable surface temperature information. Furthermore, the temperature resolution of radiation measurements cannot meet the accuracy requirements for measuring thermal deformation.

[0004] With the improvement of light source performance, the power density of the emitted beam continues to increase, and the thermal load on the monochromator crystal has a greater impact on lattice deformation. The high thermal load operating conditions also place higher demands on the cooling system. Therefore, it is urgent to solve the problem of measuring the thermal deformation of the monochromator crystal surface in the radiation working environment, and thus fundamentally solve the problem of heat release design for high-power dual-crystal monochromators under different operating conditions. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a method for measuring the thermal deformation of a synchrotron radiation spectrometer, which can accurately measure the surface thermal deformation distribution of a high-power dual-crystal monochromator.

[0006] This invention provides a method for measuring the thermal load deformation of a synchrotron radiation spectroscopic crystal, comprising:

[0007] Step S1: Place an analytical crystal at the light output port of the monochromator that is spatially orthogonal to the first crystal and the second crystal of the monochromator. After the synchrotron radiation beam passes through the first crystal, the second crystal and the analytical crystal in sequence, a diffracted beam is generated. The diffracted beam is incident on the imaging detector to obtain the Dumond diagram of the first crystal during thermal deformation.

[0008] Step S2: According to the Dumond diagram, obtain the intensity of the emitted light when the first crystal is thermally deformed in the first crystal.

[0009] Step S3: Use X-ray simulation software to obtain the intensity distribution of emitted light under different detuning angles;

[0010] Step S4: Based on the distribution of emitted light intensity on the first crystal surface and the distribution of emitted light intensity at different detuning angles, obtain the detuning angle distribution at different positions on the first crystal surface;

[0011] Step S5: Construct a geometric model. Based on the geometric model and the detuning angle distribution at different positions on the first crystal surface, obtain the thermal deformation distribution at different positions on the first crystal surface to realize the measurement of thermal load deformation of the synchrotron radiation spectroscopic crystal.

[0012] Furthermore, the first crystal, the second crystal, and the analytical crystal are all made of single-crystal silicon, and the diffraction plane index is 333.

[0013] Further, step S2 includes:

[0014] Step S21: Project the light spot on the Dumond image onto the vertical direction and restore it to the position coordinates of the first crystal surface, so as to restore the size of the light spot on the Dumond image to the vertical size of the beam at the front end of the monochromator.

[0015] Step S22: Since the synchrotron radiation beam is incident at the Bragg angle, the vertical dimension of the beam needs to be converted into the size of the spot on the first crystal surface that is illuminated, so as to obtain the output light intensity corresponding to the coordinates of each position in the vertical direction at the light trace on the first crystal surface.

[0016] Further, step S3 includes:

[0017] Step S31: Obtain the swing curves of the diffraction of the first crystal and the second crystal to the synchrotron radiation beam using X-ray simulation software;

[0018] Step S32: Keep the rocking curve of the second crystal unchanged, translate the rocking curve of the first crystal, and obtain the overlapping area of ​​the rocking curves of the first crystal and the second crystal under a series of different detuning angles.

[0019] Further, step S4 includes: making the emitted light intensity distributed on the first crystal surface correspond one-to-one with the emitted light intensity of the monochromator at different detuning angles, and making the corresponding emitted light intensities equal, to obtain the detuning angle at the corresponding position on the first crystal diffraction surface caused by thermal deformation, and the set of detuning angles at each position constitutes the detuning angle distribution at different positions on the first crystal surface.

[0020] Further, step S5 includes:

[0021] Step S51: Use a circular arc to simulate the surface morphology of the first crystal during thermal deformation. The chord of the arc is the flat surface of the first crystal when it has not undergone thermal deformation. The midpoint of the arc is the maximum deformation height of the first crystal during thermal deformation, and the corresponding detuning angle is 0°. The central angle from the edge of the arc to the midpoint of the arc is the maximum detuning angle of the first crystal during thermal deformation, and the corresponding deformation height is 0.

[0022] Step S52: Substitute the vertical spot size d at the light trace on the first crystal surface into the detuning angle distribution at different positions on the first crystal surface to obtain the maximum detuning angle β during thermal deformation of the first crystal;

[0023] Step S53: Based on the spot size d and the maximum detuning angle β, obtain the maximum deformation height H and the radius of curvature r of the circular arc;

[0024] Step S54: Based on the functional relationship h=r(cosα-1)+H between the detuning angle α at any position on the first crystal surface and the deformation height h, obtain the thermal deformation height distribution at different positions in the vertical direction of the light trace on the first crystal surface.

[0025] Furthermore, the maximum deformation height H and the radius of curvature r of the circular arc in step S53 are obtained by the following formula:

[0026]

[0027] In the formula, d is the size of the spot in the vertical direction at the light trace on the surface of the first crystal, and β is the maximum detuning angle of the first crystal during thermal deformation.

[0028] This invention achieves high-precision measurement of the thermal load deformation of a spectroscopic crystal in a radiation environment by exploiting the effect of local detuning of a dual-crystal monochromator on the emitted light. The concept is ingenious, the steps are simple, and the principle is clear and reasonable. Attached Figure Description

[0029] Figure 1 This is a flowchart of a method for measuring the thermal load deformation of a synchrotron radiation spectrometer according to the present invention.

[0030] Figure 2 This is an experimental configuration diagram according to a specific example of the present invention.

[0031] Figure 3 This is a schematic diagram of the rocking curve of a monochromator with two crystals.

[0032] Figure 4 It is a geometric relationship diagram between the deformation height of the crystal surface and the detuning angle. Detailed Implementation

[0033] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0034] The method for measuring the thermal deformation of a synchrotron radiation spectroscopic crystal provided by this invention focuses on the area irradiated by the synchrotron radiation beam rather than the entire crystal, and the measurement range is limited to the beam trace. Furthermore, since the synchrotron radiation beam is uniformly distributed horizontally, its thermal deformation can be obtained through translation; therefore, this invention measures the vertical thermal deformation at the beam trace on the crystal surface.

[0035] like Figure 1 As shown, the method for measuring the thermal load deformation of a synchrotron radiation spectroscopic crystal provided by the present invention includes the following steps:

[0036] Step S1: Place an analytical crystal at the output port of the monochromator that is spatially orthogonal to the first and second crystals of the monochromator. After the synchrotron radiation beam passes through the first crystal, the second crystal, and the analytical crystal in sequence, a diffracted beam is generated. The diffracted beam is incident on the imaging detector to obtain the DuMond pattern of the first crystal during thermal deformation.

[0037] Ideally, both the first and second crystals of the monochromator are perfect crystals, free from thermal deformation, and the two crystals are strictly parallel, without any detuning of the diffraction planes. In this case, the Dumond diagram is an ideal, uniform parallelogram. However, in practical applications, due to the high power density of the synchrotron radiation beam, most of the energy is absorbed by the first crystal, and the thermal load on the second crystal is negligible. This results in excessive thermal load on the surface of the first crystal, causing deformation, while the second crystal remains a perfect crystal with a flat surface. Therefore, the thermal load deformation of the first crystal surface is the same as the thermal load deformation of the monochromator crystal.

[0038] The first crystal, second crystal, and analytical crystal mentioned above are all made of single-crystal silicon, with a diffraction plane index of 333, denoted as Si(333). When the first crystal undergoes thermal deformation, the width of both ends of the originally ideal parallelogram on the imaging detector narrows, forming a 45° tilted oval shape. This 45° tilted parallelogram is the Dumond diagram when the monochromator crystal undergoes thermal deformation. The Dumond diagram is a Bragg equation image representation reflecting the relationship between the crystal diffraction angle and the beam wavelength. In the Dumond diagram obtained in this invention, the horizontal axis is the horizontal divergence angle of the diffracted beam, and the vertical axis is the output light wavelength of the dual-crystal monochromator.

[0039] It should be noted that the monochromator crystal has a low-index surface 111 and a high-index surface 333. When a synchrotron radiation source is incident, both the low-index surface 111 and the high-index surface 333 diffract simultaneously. The energy of the diffracted beam from the low-index surface 111 is 6 keV, while the energy of the higher harmonics generated by the high-index surface 333 is 18 keV. To increase measurement sensitivity, this invention uses the higher harmonics generated by the high-index surface 333 for measurement.

[0040] Step S2: Based on the Dumond diagram obtained in step S1, obtain the distribution of emitted light intensity on the surface of the first crystal during thermal deformation. Specifically, step S2 includes:

[0041] Step S21: Project the light spot on the Dumond diagram onto the vertical direction and restore it to the position coordinates of the first crystal surface to subtract the broadening caused by the beam divergence angle during transmission, and restore the size of the light spot on the Dumond diagram to the vertical size of the beam at the front end of the monochromator.

[0042] Step S22: The synchrotron radiation beam is incident at a Bragg angle to convert the vertical dimension of the beam into the size of the spot on the surface of the first crystal, thereby obtaining the output light intensity corresponding to the coordinates of each position in the vertical direction at the light trace on the surface of the first crystal, that is, obtaining the distribution of the output light intensity on the surface of the first crystal during thermal deformation.

[0043] Step S3 involves using X-ray simulation software to obtain the intensity distribution of the emitted light at different detuning angles. Specifically, step S3 includes:

[0044] Step S31: Obtain the swing curves of the diffraction of the synchrotron radiation beam by the first and second crystals using X-ray simulation software.

[0045] The horizontal axis of the rocking curve represents the difference between the diffraction angle and the Bragg angle, while the vertical axis represents the crystal reflectivity, reflecting the crystal's reflectivity for incident light of a specific energy at different diffraction angles. In this invention, the two crystals of the monochromator have identical rocking curves, both being Si(333) reflectivity curves for 18keV higher harmonics at different angles. The emitted beam of the dual-crystal monochromator is the overlapping portion of the rocking curves of the two crystals. Without thermal deformation, the two crystals are strictly parallel, their rocking curves overlap, and the emitted light intensity is maximum. However, after thermal deformation of the first crystal, the diffraction planes of the two crystals are no longer strictly parallel, equivalent to a local detuning between the two crystals. At this time, the rocking curve of the first crystal shifts while the rocking curve of the second crystal remains unchanged. The overlapping area of ​​the rocking curves of the two crystals decreases, and the emitted light flux also decreases.

[0046] Therefore, in step S32, the rocking curve of the second crystal is kept unchanged, and the rocking curve of the first crystal is translated to obtain the overlapping area of ​​the rocking curves of the first crystal and the second crystal under a series of different detuning angles, thereby obtaining the output light intensity of the monochromator under different detuning angles.

[0047] The detuning angle refers to the minute angular deviation between the diffraction planes of a dual-crystal monochromator when the two crystals are no longer perfectly parallel. It should be noted that the detuning angle referred to in this invention is a localized detuning caused by thermal deformation of the first crystal surface while the second crystal surface remains unchanged, not an angular shift across the entire crystal. The magnitude of the detuning angle depends on the surface morphology of the first crystal after thermal deformation; the detuning angle varies at different locations.

[0048] Therefore, in step S4, the distribution of the outgoing light intensity at different positions on the first crystal surface is obtained based on the distribution of the outgoing light intensity on the first crystal surface and the distribution of the outgoing light intensity at different detuning angles.

[0049] Specifically, the intensity of the emitted light distributed on the surface of the first crystal is made to correspond one-to-one with the intensity of the emitted light of the monochromator under different detuning angles, and the two corresponding emitted light intensities are made equal, so as to obtain the detuning angles at corresponding positions on the diffraction surface of the first crystal caused by thermal deformation. The set of detuning angles at each position is the distribution of thermal deformation detuning angles at different positions in the vertical direction of the light trace on the surface of the first crystal.

[0050] Step S5: Construct a geometric model. Based on the geometric model and the detuning angle distribution at different positions on the first crystal surface, obtain the thermal deformation distribution at different positions on the first crystal surface to achieve high-precision measurement of thermal load deformation of the synchrotron radiation spectroscopic crystal.

[0051] Specifically, step S5 includes:

[0052] Step S51: Use a circular arc to simulate the surface morphology of the first crystal during thermal deformation. The chord of the arc is the flat surface of the first crystal when it has not undergone thermal deformation. The midpoint of the arc is the maximum deformation height of the first crystal during thermal deformation, and the corresponding detuning angle is 0°. The central angle from the edge of the arc to the midpoint of the arc is the maximum detuning angle of the first crystal during thermal deformation, and the corresponding deformation height is 0.

[0053] Step S52: Substitute the vertical spot size d at the light trace on the first crystal surface into the detuning angle distribution at different positions on the first crystal surface to obtain the maximum detuning angle β during thermal deformation of the first crystal.

[0054] Step S53: Based on the spot size d and the maximum detuning angle β, obtain the maximum deformation height H and the radius of curvature r of the circular arc. The maximum deformation height H and the radius of curvature r of the circular arc are obtained by the following formula:

[0055] and

[0056] Step S54: Based on the functional relationship h=r(cosα-1)+H between the detuning angle α at any position on the first crystal surface and the deformation height h, obtain the thermal deformation height distribution at different positions in the vertical direction of the light trace on the first crystal surface.

[0057] The measurement method of this invention combines orthogonal analytical crystals and imaging detectors to diagnose the influence of local detuning caused by thermal deformation of the first crystal surface in a dual-crystal monochromator on the emitted light. By analyzing the detuning angle and the change in emitted light intensity, the correspondence between the coordinates of the light trace at the first crystal and the detuning angle is obtained, thus revealing the change in morphology height caused by thermal deformation. This invention has the following beneficial effects:

[0058] 1) This invention utilizes higher-sensitivity higher-order harmonics and combines an analytical crystal with the same index plane orthogonal to the monochromator scattering surface downstream of the monochromator to analyze the thermal deformation of a dual-crystal monochromator under the Si(333) index condition. The Darwin bandwidth of Si(333) diffraction is narrower, only 1 / 3 of that of Si(111), which allows for better observation of the detuning phenomenon between the first and second crystals in the dual-crystal monochromator and the resulting changes in light intensity.

[0059] 2) This invention uses analytical crystals with the same index planes arranged orthogonally. After adjusting the diffraction angle of the analytical crystal, the Dumond pattern of the dual-crystal monochromator can be directly obtained on the two-dimensional imaging detector without adjusting other parameters. This greatly simplifies the experimental steps, saves time, and is convenient and fast.

[0060] 3) This invention considers the two diffractions of the monochromator separately and calculates the intensity of the emitted light by the overlapping part of the rocking curves of the two crystals. It can reflect the influence of local detuning on the emitted light on the twin crystal surfaces. In the case of thermal deformation on the crystal surface, it is more accurate than directly calculating the emitted light by the rocking curve of the monochromator.

[0061] 4) The analysis and processing of the Dumond diagram in this invention mainly focuses on the intensity of the diffracted light corresponding to different positions. Compared with the bandwidth of the diffracted light, the light intensity information is more sensitive to the local detuning of the twin crystal after thermal deformation, that is, it has higher characterization accuracy.

[0062] 5) This invention utilizes geometric relationships to link the detuning angle and the thermal deformation height. By analyzing the Dumond image and comparing it with the light intensity distribution of the simulated detuning process, it realizes the measurement of the surface morphology of the spectroscopic crystal under thermal deformation during the operation of the monochromator under high thermal load in a strong radiation environment.

[0063] To better understand, the present invention will be described in detail below through a specific example.

[0064] Step S1, as follows Figure 2As shown, a synchrotron radiation source emits an X-ray beam. A dual-crystal monochromator is placed 21m from the source, and an analytical crystal is placed 39m from the source and orthogonal to the dual-crystal monochromator. The imaging detector, a CMOS sensor, is placed 39.5m from the source. The X-ray beam is split and selectively output by the monochromator, and then diffracted by the orthogonal analytical crystal, achieving decoupling of angle and energy. Finally, a spot tilted at 45° to the original outgoing beam is obtained on the CMOS sensor, i.e., the Dumond pattern.

[0065] Step S2: Integrate the Domond diagram laterally and remove background interference to obtain the spatial distribution of the emitted light intensity in the vertical direction on the sensor; normalize the distribution using the maximum intensity value as the denominator to obtain the relative intensity distribution; using the actual beam divergence angle and the transmission optical path distance as a ratio, restore the vertical size of the light spot on the sensor to the vertical size of the beam at the monochromator front end. Then, incident the beam at 19.24° to obtain the size of the light spot irradiated on the first crystal surface, and thus obtain the emitted light intensity distribution at different positions in the vertical direction on the first crystal surface.

[0066] Step S3: Obtain the rocking curve of the Si(333) crystal using X-ray simulation software, such as... Figure 3 As shown, the dashed line represents the rocking curve of the first crystal, and the solid line represents the rocking curve of the second crystal. The detuning angle of the twin crystals is α'. Keeping the rocking curve of the second crystal unchanged, the rocking curve of the first crystal is translated, i.e., the size of α' is changed, to simulate the local detuning process. The overlapping area of ​​the rocking curves of the two crystals at different detuning angles is calculated, and the corresponding intensity of the emitted light is obtained. Then, the maximum area when the twin crystals overlap is used as the denominator for normalization, thus obtaining the intensity distribution of emitted light at different detuning angles after the thermal deformation of the first crystal.

[0067] Step S4 involves relating the intensity distribution obtained from the rocking curve with the actual intensity distribution obtained from the Dumond diagram to obtain the detuning angle at various points in the vertical direction of the first crystal surface.

[0068] Step S5, as follows Figure 4As shown, the straight line AB simulates the flat surface of the first crystal of the monochromator before thermal deformation, and the length d of line segment AB is the vertical spot size at the light trace on the surface of the first crystal. The circular arc ACB simulates the surface morphology after thermal deformation, where r is the radius of curvature, C is the midpoint of the arc, and E is any point on the arc ACB. The distance from E to the straight line AB is the deformation height h at E. At this point, the central angle corresponding to the arc EC is equal to the detuning angle α at E. The detuning angle α has a functional relationship with the deformation height h: h = r(cosα-1) + H. The distance from point C to the straight line AB is the maximum deformation height H of the first crystal during thermal deformation, and the corresponding detuning angle α is 0°. The central angle β corresponding to the distance from point A to the midpoint C is the maximum detuning angle of the crystal during thermal deformation, and the corresponding thermal deformation height is 0 (points B and A are both boundary points, and the situation is the same as at point A).

[0069] The vertical dimension of the light spot allowed to pass through the slit on the beam is 2 mm. With an incident beam of 19.24° Bragg diffraction at 18 keV from Si(333), the vertical spot size d at the light trace on the first crystal surface is 6.07 mm (i.e., the length of line segment AB). Substituting this into the detuning angle distribution, the maximum detuning angle β of thermal deformation is obtained. From geometric relationships:

[0070] and

[0071] Find the radius of curvature r of the arc and the maximum deformation height H, and then substitute r and H into the functional relationship h = r(cosα-1) + H of the detuning angle α and the deformation height h to obtain the vertical thermal deformation height distribution at the light trace on the surface of the first crystal.

[0072] This invention is ingeniously conceived, with simple steps and a clear and reasonable principle. By diagnosing the impact of local detuning of a dual-crystal monochromator on the emitted light, it achieves high-precision measurement of the thermal load deformation of the spectroscopic crystal in the radiation environment. This fills the gap in the field of synchrotron radiation technology for the actual measurement of thermal deformation on the surface of high-power dual-crystal monochromators, and provides a new foundation and possibility for the further development of low-temperature monochromators.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A method for measuring the thermal load deformation of a synchrotron radiation spectroscopic crystal, characterized in that, The method comprises the following steps: S1, placing an analysis crystal which is spatially orthogonal to the first crystal and the second crystal of the monochromator at the light outlet of the monochromator, and the synchrotron radiation beam passes through the first crystal, the second crystal and the analysis crystal in sequence to generate a diffraction beam, and the diffraction beam is incident on an imaging detector to obtain a Du Mond plot of the first crystal when the first crystal is thermally deformed; S2, obtaining the distribution of the light intensity on the surface of the first crystal when the first crystal is thermally deformed according to the Du Mond plot; S3, obtaining the distribution of the light intensity under different misalignment angles by using X-ray simulation software; S4, obtaining the misalignment angle distribution of different positions on the surface of the first crystal according to the distribution of the light intensity on the surface of the first crystal and the distribution of the light intensity under different misalignment angles; S5, constructing a geometric model, and obtaining the thermal deformation distribution of different positions on the surface of the first crystal according to the geometric model and the misalignment angle distribution of different positions on the surface of the first crystal, so as to realize the measurement of the thermal deformation of the synchrotron radiation beam.

2. The method according to claim 1, wherein, The first crystal, the second crystal and the analysis crystal are all single crystal silicon, and the diffraction crystal face index is all 333.

3. The method of claim 1, wherein the method is a method of measuring thermal deformation of a synchrotron radiation spectroscopy crystal, the method comprising: The step S2 comprises: S21, projecting the light spot on the Du Mond plot to the vertical direction and restoring it to the position coordinates on the surface of the first crystal, so as to restore the size of the light spot on the Du Mond plot to the vertical size of the light beam at the front end of the monochromator; S22, because the synchrotron radiation beam is incident at the Bragg angle, the vertical size of the light beam needs to be converted into the size of the light spot irradiated on the surface of the first crystal, so as to obtain the light intensity corresponding to each position coordinate in the vertical direction at the light trace on the surface of the first crystal.

4. The method of claim 1, wherein the method is a method of measuring thermal deformation of a synchrotron radiation spectroscopy crystal. The step S3 comprises: S31, obtaining the rocking curve of the synchrotron radiation beam diffracted by the first crystal and the second crystal by using X-ray simulation software; S32, keeping the rocking curve of the second crystal unchanged, and translating the rocking curve of the first crystal to obtain the overlapping area of the rocking curves of the first crystal and the second crystal under a series of different misalignment angles.

5. The method of claim 1, wherein the method is a method of measuring thermal deformation of a synchrotron radiation spectroscopy crystal. The step S4 comprises: making the light intensity distributed on the surface of the first crystal correspond to the light intensity of the monochromator under different misalignment angles, and making the corresponding light intensity equal, so as to obtain the misalignment angle of the corresponding position on the diffraction surface of the first crystal caused by thermal deformation, and the set of misalignment angles of each position is the misalignment angle distribution of different positions on the surface of the first crystal.

6. The method of claim 1, wherein the method is a method of measuring thermal deformation of a synchrotron radiation spectroscopy crystal. The step S5 comprises: S51, simulating the surface topography of the first crystal when it is thermally deformed by using a circular arc, the chord of the circular arc is the flat surface of the first crystal when it is not thermally deformed, the midpoint of the circular arc is the maximum deformation height of the first crystal when it is thermally deformed, the corresponding misalignment angle is 0°, the central angle from the edge of the circular arc to the midpoint of the circular arc is the maximum misalignment angle of the first crystal when it is thermally deformed, and the corresponding deformation height is 0. Step S52, obtaining the spot size of the light at the vertical direction of the first crystal surface light trace Substitute the distribution of the detuning angle at different positions of the first crystal surface, and obtain the maximum detuning angle when the first crystal is thermally deformed ; Step S53, obtaining the maximum deformation height and the maximum detuning angle according to the spot size and the circular arc curvature radius ; Step S54, obtaining the thermal deformation height distribution at different positions in the vertical direction of the light trace of the first crystal surface according to the misorientation angle of any position of the first crystal surface and the function relationship of the deformation height and the function relationship of the deformation height , obtaining the thermal deformation height distribution at different positions in the vertical direction of the light trace of the first crystal surface 7. The method according to claim 6, wherein the method is characterized by, the maximum deformation height in the step S53 and the circular arc radius of curvature is obtained by the following equation: ， ， wherein is the spot size in the vertical direction at the light trace of the first crystal surface, is the maximum detuning angle at the thermal deformation of the first crystal.

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