In-situ testing method and device for thermal deformation of a synchrotron monochromator

Abstract

The application discloses a kind of in-situ testing method and device for thermal deformation of synchrotron monochromator.The method is: first insert, second insert are sequentially arranged along the direction of electron beam on the linear section of synchrotron storage ring, and the double-crystal monochromator to be measured is arranged on the beamline downstream of the second insert;Close the first insert, adjust the magnetic gap of the second insert, so that the first crystal generates the probe light without thermal deformation, and measure the rocking curve of the second crystal at different positions of the first crystal at this time, according to each rocking curve, the height distribution h (x,y)‑0 Of the first crystal surface in the state without thermal deformation is obtained;Adjust the magnetic gap of the first insert, and record the rocking curve of the second crystal at each magnetic gap value after the first insert is adjusted, to obtain the height distribution h (x,y)‑i Of the first crystal surface under current thermal load;The thermal deformation distribution of the first crystal under corresponding thermal load is obtained by h (x,y)‑i -h (x,y)‑0 .

Description

Technical Field

[0001] This invention belongs to the field of synchrotron radiation optical engineering technology, and relates to a method for testing the thermal deformation of a synchrotron radiation monochromator. Specifically, it relates to an in-situ testing method and apparatus for the thermal deformation of a synchrotron radiation monochromator based on a series insert, which is suitable for performance evaluation of high-heat-load optical components in fourth-generation synchrotron radiation sources. Background Technology

[0002] Synchrotron radiation sources are major scientific facilities that generate high-brightness, wide-band, continuous-spectrum X-rays, widely used in cutting-edge basic research fields such as materials science, life sciences, and condensed matter physics. Extracting monochromatic light of specific wavelengths from synchrotron radiation white light is a fundamental prerequisite for quantitative analysis at most experimental stations. This function is performed by the core optical equipment on the beamline—the monochromator (usually a dual-crystal monochromator for hard X-ray bands). During beamline operation, the first crystal of the monochromator receives the high-power X-ray beam generated by the insert (undulator or oscillator) source, depositing a huge heat load, which in turn causes thermal deformation (dimpling, protrusion, or twisting) on ​​the crystal surface. This thermal deformation directly reduces the monochromator's diffraction efficiency, energy resolution, and beam pointing stability, severely affecting beam quality. Especially for fourth-generation synchrotron radiation sources, with their lower emittance and order-of-magnitude increase in power density, the thermal deformation effect is even more severe. Therefore, accurately measuring the thermal deformation of the monochromator under real operating conditions is crucial for optimizing cooling schemes, evaluating crystal performance, and designing beamlines.

[0003] Currently, methods for testing monochromator thermal deformation mainly fall into two categories. One category involves altering the overall thermal load incident on the monochromator by changing the beam current intensity in the storage ring, and then measuring the changes in monochromator performance parameters under different current intensities to assess the degree of thermal deformation. However, this method must be performed within the accelerator's dedicated operating time, involves significant adjustments to global beam parameters, and is extremely costly, time-consuming, and inflexible, failing to meet the needs of routine monochromator testing or rapid evaluation. Another approach involves using a high-power laser outside the monochromator to simulate a synchrotron radiation heat source for heating tests. While this method is independent of accelerator runtime, its inherent drawbacks are: the laser incident direction is difficult to keep coaxial with the actual synchrotron radiation path, resulting in a significant difference between the heat source power distribution on the crystal surface (including spot shape and energy density gradient) and the characteristic distribution produced by the actual insert; simultaneously, the laser heating window and optical path channel must be pre-integrated during the monochromator design phase, making it unsuitable for existing monochromators; and the external optical path often creates spatial conflicts with the probe optical path and cooling structure, limiting the test field of view and angle; furthermore, the heat from laser heating is only deposited on the crystal surface, while X-rays have a certain penetration depth, resulting in fundamentally different energy deposition distributions (volume absorption and surface absorption) within the crystal. Therefore, existing testing methods struggle to achieve low-cost, highly flexible, and real-world equivalent in-situ testing of monochromator thermal deformation at both the heat source geometry and energy deposition physics levels. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a method and apparatus for in-situ testing of thermal deformation of synchrotron radiation monochromators. This invention solves the problem of existing technologies' difficulty in simultaneously achieving low cost, high flexibility, and close approximation to actual operating conditions for in-situ testing of monochromator thermal deformation.

[0005] The technical solution of this invention is as follows: A method for in-situ testing of thermal deformation of a synchrotron monochromator, comprising the following steps: For a first insert and a second insert arranged sequentially along the electron beam direction on a straight section of a synchrotron radiation storage ring, the dual-crystal monochromator to be tested is placed on the beamline downstream of the second insert; a movable beam blocker is set in front of the first crystal of the dual-crystal monochromator to adjust the beam size incident on the first crystal; and a detector is set behind the second crystal of the dual-crystal monochromator. Close the first insert (magnetic gap adjusted to maximum), adjust the magnetic gap of the second insert to generate probe light that prevents thermal deformation of the first crystal; use the detector to measure the rocking curves of the second crystal when the probe light is incident on different positions of the first crystal, and obtain the angular distribution of the first crystal planes in the state of no thermal deformation based on the diffraction peak angles of each rocking curve; then obtain the height distribution h of the first crystal planes in the state of no thermal deformation based on the angular distribution of the first crystal planes in the state of no thermal deformation. (x,y)-0 ; The magnetic gap of the first insert is adjusted to gradually increase the thermal load incident on the first crystal. At each adjusted magnetic gap value, the detector is used to record the rocking curve of the second crystal. Based on these rocking curves under the current thermal load, the height distribution h of the first crystal plane under the current thermal load is obtained. (x,y)-i ; By calculating h (x,y)-i - h (x,y)-0 The thermal deformation distribution of the first crystal under the corresponding thermal load is obtained.

[0006] Preferably, the detector is a two-dimensional detector. The two-dimensional detector is used to obtain a rocking curve image for each magnetic gap value after the first insert is adjusted, and the angle distribution of the first crystal plane under the current thermal load is obtained based on the rocking curve image.

[0007] Preferably, the detector is a one-dimensional detector. The one-dimensional detector is used to measure the diffraction peak angles corresponding to multiple different positions on the first crystal surface for each magnetic gap value after the first insert is adjusted. Then, the angle distribution of the first crystal surface under the current thermal load is calculated based on the peak angles corresponding to multiple different positions on the first crystal surface.

[0008] Preferably, a monochromatic light slit is provided downstream of the second crystal. When the one-dimensional detector is used to scan different spatial positions on the surface of the first crystal to obtain the thermal deformation distribution, the spatial position of the beam emitted after the probe light is diffracted by the first crystal is selected through the monochromatic light slit, so as to realize the spatial resolution measurement of different diffraction points on the surface of the first crystal.

[0009] Preferably, the opening widths of the monochromatic light slit in the horizontal and vertical directions are independently adjustable.

[0010] Preferably, the aperture of the beam blocker is continuously adjustable.

[0011] Preferably, taking into account the diffraction flux, energy bandwidth and corresponding dynamic diffraction width of the probe light, the magnetic gap of the second insert is adjusted to generate probe light that causes no thermal deformation of the first crystal.

[0012] A synchrotron monochromator thermal deformation in-situ testing device, characterized in that it includes a first insert, a second insert, a beam blocker, a detector, a control system, and a data acquisition system, which are sequentially arranged along the electron beam direction on a straight section of the synchrotron storage ring. The magnetic gap of the first insert is adjustable, and the output synchrotron radiation power can be controlled by changing the size of the magnetic gap, so as to apply a controllable thermal load to the first crystal of the dual-crystal monochromator under test. The magnetic gap of the second insert is adjustable, which is used to generate probe light that prevents thermal deformation of the first crystal; The beam blocker is disposed downstream of the second insert and upstream of the dual-crystal monochromator under test in the optical path, and is used to adjust the beam size incident on the first crystal; The dual-crystal monochromator is positioned on the beam line downstream of the second insert. The first crystal is used to receive the heating beam generated by the first insert and the probe beam generated by the second insert. The second crystal is used to perform angle scanning on the probe beam after diffraction by the first crystal to achieve the measurement of the rocking curve. The detector is used to record the intensity of diffracted light at different angles of the second crystal, thereby obtaining the rocking curve; The control system and data acquisition system are respectively connected to the magnetic gap driving mechanism of the first insert, the magnetic gap driving mechanism of the second insert, the driving mechanism of the beam blocker, the rotation mechanism of the second crystal, and the detector. They are used to uniformly control the magnetic gap of the first insert, the aperture of the beam blocker, the angle scanning of the second crystal, and synchronously record the diffraction intensity signal of the detector at each scanning angle. The system calculates the angle distribution of the first crystal facets based on the acquired rocking curve data; then, it obtains the height distribution of the first crystal facets based on the angle distribution under no-thermal-deformation conditions; and finally, it calculates the height distribution h of the first crystal facets based on the height distribution h under no-thermal-deformation conditions. (x,y)-0 and the height distribution h of the first crystal plane under the i-th thermal load (x,y)-i The thermal deformation distribution of the first crystal under the i-th thermal load is obtained.

[0013] The advantages of this invention are as follows: 1. Low cost and high flexibility: No need to change the storage circulation strength, no occupation of valuable dedicated accelerator running time and user-dedicated machine time, and testing can be carried out at any time during regular user operation intervals, significantly reducing testing costs.

[0014] 2. A more realistic simulation heating method: The thermal load generated by the first insert and the probe light generated by the second insert are completely coaxial and both propagate along the actual synchrotron radiation path. The spatial distribution of the heat source (especially the power density distribution in the horizontal / vertical directions) is realistically determined by the insert parameters, resulting in higher simulation fidelity compared to external laser heating. More importantly, this invention uses X-rays as the heating source, whose heat is deposited inside the crystal with a certain penetration depth (volume absorption), perfectly consistent with actual service conditions; while the heat from laser heating is only deposited on the crystal surface (surface absorption). The temperature gradient distribution and thermal strain evolution mechanism inside the crystal are fundamentally different. This invention achieves equivalence to actual conditions at both the geometric path of the heat source and the physical mechanism of energy deposition, with simulation fidelity far exceeding that of external laser heating.

[0015] 3. Independently controllable heating power: By changing the magnetic gap of the first insert, the thermal load can be finely, stably, and repeatedly adjusted from zero to the maximum value without modifying any other optical components or beam parameters.

[0016] 4. No additional optical path interference: There is no need to introduce additional optical components such as lasers and mirrors outside the monochromator, thus avoiding problems such as optical path obstruction, limited field of view and interference from cooling structure.

[0017] 5. Applicable to existing equipment: This method can be directly applied to existing storage ring beamlines with dual insert tandem configurations, without requiring any hardware modifications to the monochromator itself. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the optical path structure of the testing device of the present invention.

[0019] Figure 2 This is a schematic diagram of the rocking curve of the first crystal at a certain spatial position under different thermal loads (different magnetic gaps of the first insert) using the test method of the present invention.

[0020] Figure 3 This is a schematic diagram of the two-dimensional thermal deformation distribution obtained by the rocking curve imaging method (when using a two-dimensional detector).

[0021] Figure 4 This is a schematic diagram showing the relationship between the magnetic gap of the first insert and the radiation power. Detailed Implementation

[0022] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0023] The core idea of ​​this invention is to utilize two inserts arranged in series on a storage ring linear joint, wherein the upstream insert serves as a variable power heating source and the downstream insert serves as a stable probe light source; by changing the magnetic gap of the upstream insert, its output synchrotron radiation power can be independently controlled, and this power irradiates and heats the first crystal of the monochromator under test in a coaxial manner; at the same time, the low-power probe light generated by the downstream insert is diffracted by the first crystal and then the change of the peak position of the rocking curve of the second crystal of the rocking monochromator is measured, thereby retrieving the thermal deformation of the crystal.

[0024] This invention provides a method for testing the thermal deformation of a synchrotron monochromator, comprising the following steps: Step 1: Set up the test optical path On a straight section of a synchrotron radiation storage ring, a first insert (serving as a heating source) and a second insert (serving as a probe light source) are sequentially arranged along the electron beam direction. The monochromator under test (e.g., a dual-crystal monochromator) is positioned on the beamline downstream of the second insert. A movable beam blocker (e.g., a white light adjustable aperture, which can be used to switch the light on and off and limit the size of the light) is placed in front of the first crystal of the monochromator, and an X-ray detector is placed behind the second crystal.

[0025] Step 2: Set the initial baseline state 1. Close the first insert (magnetic gap opened to the maximum, radiation power is negligible).

[0026] 2. Set the magnetic gap of the second insert to an appropriate fixed value to generate low-power, high-brightness probe light. This power level should not cause significant thermal effects on the first crystal of the monochromator. The selection of this magnetic gap value needs to comprehensively consider the diffraction flux, energy bandwidth, and corresponding dynamic diffraction width of the probe light to ensure that the probe light still has a sufficient exit angle for effective detection after the monochromator experiences crystal plane bending or lattice distortion under high thermal load. For example, for a gyroscope light source, its magnetic gap should be no less than 50 mm and no more than 80 mm, so that its output power is no higher than 50 W, while still having sufficient luminous flux.

[0027] 3. Use a monochromatic slit to draw a narrow beam of light, and record the initial center position coordinates of the slit as (0, 0). Rock the second monochromator crystal, and use a detector to record the rocking curve of the second crystal. Record the diffraction peak angle of this rocking curve as θ. (0,0)-0.

[0028] 4. Change the center position coordinates of the slit to (x, y), repeat the previous step, and obtain the diffraction peak angle of the rocking curve as θ. (x,y)-0 The angular distribution of the first crystal plane of the monochromator in the state without thermal deformation is obtained from the diffraction peak positions of each rocking curve. Integrating along the (x,y) direction, the height distribution h of the first crystal of the monochromator in this state can be obtained. (x,y)-0 This is the baseline state under conditions without thermal deformation.

[0029] Step 3: Apply a controllable thermal load The total radiated power and spatial power density distribution of the synchrotron radiation insert can be precisely calculated based on the parameters of the synchrotron radiation source and the insert (magnetic gap, period length, magnetic field strength, etc.). Therefore, the thermal load applied to the first crystal can be precisely controlled by adjusting the magnetic gap of the first insert. Specifically, the magnetic gap of the first insert is gradually reduced from its maximum value (a decrease in magnetic gap leads to an increase in radiated power), thereby progressively increasing the total thermal power incident on the monochromator's first crystal. Throughout the entire thermal load application process, the storage circulation current strength, electron energy, and the magnetic gap of the second insert are kept constant.

[0030] Step 4: In-situ measurement of thermal deformation Under each magnetic gap setting value for the first insert: 1. Wait for a period of time to allow the thermal deformation of the first crystal of the monochromator to reach thermal equilibrium (temperature stability).

[0031] 2. Repeat steps 3-4 in step two to obtain the crystal deformation h under the corresponding thermal load conditions. (x,y)-i .

[0032] Step 5: Inversion of thermal deformation Calculate h (x,y)-i - h (x,y)-0 This allows us to obtain the thermal deformation morphology of the first crystal under the corresponding thermal load (such as the change in bulge / depression height with position). If a two-dimensional detector is used, the thermal deformation distribution in the two-dimensional plane of the first crystal can be directly obtained through the rocking curve image method, without the need to scan the crystal point by point using a monochromatic light slit.

[0033] like Figure 1 As shown, a synchrotron monochromator thermal deformation in-situ testing device for implementing the above method includes: The first insert, positioned upstream of the linear node of the synchrotron radiation storage ring, serves as a variable-power heating source. Its magnetic gap is adjustable; by changing the size of the magnetic gap, the output synchrotron radiation power is controlled, thereby applying a controllable thermal load to the first crystal of the monochromator under test. The total radiation power and its spatial power density distribution of the first insert can be rigorously calculated based on the insert parameters.

[0034] The second insert, positioned downstream of the first insert on the same storage ring linear node, serves as a stable probe light source. The magnetic gap of this insert is fixed at a large value, ensuring that its power level does not significantly heat the monochromator's first crystal during heating, thus guaranteeing that it only serves as a probe beam without contributing additional thermal load.

[0035] A white light adjustable aperture is positioned downstream of the second insert and upstream of the monochromator under test in the optical path. The aperture of this white light adjustable aperture is continuously adjustable, with two extreme states: fully closed and fully open, as well as any partially open state in between. This white light adjustable aperture is primarily used to limit the receiving angle of the monochromator, and also serves as a thermal load on / off control function.

[0036] The monochromator under test is positioned on the beamline downstream of the second insert. This monochromator is a dual-crystal monochromator, comprising a first crystal and a second crystal. The first crystal receives the heating beam generated by the first insert and the probe beam generated by the second insert. The second crystal performs angular scanning (swinging) of the probe beam diffracted by the first crystal to measure the swing curve.

[0037] A monochromatic slit is positioned downstream of the second crystal of the monochromator under test and upstream of the X-ray detector in the optical path. The opening width of this slit is independently adjustable in both the horizontal and vertical directions. When a one-dimensional detector (such as a scintillation counter or photodiode) is used to scan different spatial positions on the surface of the first crystal to obtain the thermal deformation distribution, this monochromatic slit is used to select a specific spatial position of the beam emitted after the probe light is diffracted by the first crystal. By changing the opening position and width of the slit, spatially resolved measurements of different diffraction points on the surface of the first crystal can be achieved, thereby reconstructing the thermal deformation morphology. When a two-dimensional surface detector is used, the slit can be fully opened or moved out of the optical path.

[0038] An X-ray detector, positioned downstream of the monochromatic slit, records the intensity of diffracted light at different angles of the second crystal, thereby obtaining a rocking curve. This detector can be a point detector (such as a scintillation counter or photodiode) or a two-dimensional surface detector (such as a CCD or pixel array detector), depending on the testing requirements. When using a point detector, it works in conjunction with the monochromatic slit to scan different spatial positions on the surface of the first crystal point by point, obtaining the peak shift at each point, and thus reconstructing the one-dimensional or two-dimensional thermal deformation morphology. When using a two-dimensional detector, the thermal deformation distribution within the two-dimensional plane of the first crystal can be directly obtained through rocking curve imaging.

[0039] The control system and data acquisition system are respectively connected to the magnetic gap driving mechanism of the first insert, the magnetic gap driving mechanism of the second insert, the driving mechanism of the white light adjustable aperture, the rotation mechanism of the monochromator's second crystal, the driving mechanism of the monochromatic light slit, and the X-ray detector. The control system is used to uniformly control the step or continuous change of the magnetic gap of the first insert, the aperture and open / closed state of the white light adjustable aperture, the opening position and width of the monochromatic light slit, and the angle scanning of the second crystal; the data acquisition system is used to synchronously record the diffraction intensity signal of the X-ray detector at each scanning angle, and calculate the diffraction peak position angle and its change based on the acquired rocking curve data, thereby inverting the thermal deformation morphology.

[0040] The arrangement of the above components along the optical path is as follows: along the electron beam direction, the first insert, the second insert, the white light adjustable aperture (which can be completely closed or opened), the dual-crystal monochromator, the monochromatic light slit, and the X-ray detector are arranged sequentially; wherein the first insert and the second insert are installed in the same storage ring linear section, and the monochromator under test and subsequent optical components are installed in the optical shed of the experimental station. The heating beam generated by the first insert and the probe beam generated by the second insert propagate coaxially along the same optical path, and after passing through the white light adjustable aperture, are coaxially incident on the first crystal of the monochromator.

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the implementation of the present invention is not limited thereto.

[0042] Example 1 This embodiment uses a beamline of a fourth-generation diffraction-limited synchrotron radiation source as an example to conduct a thermal deformation test on a Si(111) dual-crystal monochromator on the beamline. Two inserts are connected in series at the corresponding storage ring linear node of the beamline: a low-temperature permanent magnet undulator (period length 22.8 mm, minimum magnetic gap 7.2 mm, maximum magnetic gap 38 mm) and a permanent magnet oscillator (period length 73 mm, minimum magnetic gap 11 mm, maximum magnetic gap 190 mm). The first insert (low-temperature permanent magnet undulator) serves as the heating source, and the second insert (permanent magnet oscillator) serves as the probe light source. The first crystal of the Si(111) dual-crystal monochromator under test is cooled by liquid nitrogen. A white light adjustable aperture is installed downstream of the second undulator and upstream of the monochromator in the optical path, and its aperture can be continuously adjusted from fully closed to fully open. The X-ray detector is a photodiode (point detector) installed downstream of the monochromatic light slit.

[0043] The testing steps are as follows: 1. Set the initial reference state: Set the white light adjustable aperture to 100 μrad, adjust the monochromator energy to 10 keV, adjust the magnetic gap of the first insert to the maximum value of 38 mm, and adjust the magnetic gap of the second insert to 60 mm. At this time, the total radiative heat power of the first insert and the second insert is 2.1W and 38W respectively, which can be regarded as the reference state under zero heat load.

[0044] 2. Apply a controllable thermal load: Gradually decrease the magnetic gap of the first undulator from 38 mm to 7.2 mm (e.g., 38, 30, 25, 20, 15, 12, 10, 8, 7.2 mm), increasing the thermal power incident on the first crystal in stages. Throughout the process, maintain the storage circulation current strength, electron energy, and magnetic gap of the second undulator constant.

[0045] 3. In-situ measurement of thermal deformation: At each magnetic gap value, after the first crystal reaches thermal equilibrium (approximately 30 minutes), the second crystal is scanned to obtain the current rocking curve. The peak angle is fitted to obtain the corresponding θ. (x,y)-i .

[0046] 4. Inversion of thermal deformation: θ (x,y)-i Integrating to obtain h (x,y)-i The thermal deformation at each spatial position on the surface of the first crystal is obtained.

[0047] Example 2 This embodiment uses a two-dimensional surface detector instead of a photodiode to achieve rapid measurement of two-dimensional thermal deformation distribution.

[0048] The detector in Example 1 was replaced with a CCD, and the monochromatic slit was fully opened. Under each magnetic gap of the first insert, the second crystal was scanned, and diffraction images at various angles were recorded by the two-dimensional detector to obtain a rocking curve imaging dataset. The peak position angle θ was fitted pixel-by-pixel. (x,y)-i The two-dimensional thermal deformation morphology distribution of the first crystal in the full beam irradiation area was reconstructed by two-dimensional integration.

[0049] This embodiment eliminates the need for point-by-point mechanical scanning, allowing for the acquisition of two-dimensional thermal deformation distribution in a single step, thus significantly improving measurement efficiency.

[0050] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for in-situ testing of thermal deformation of a synchrotron monochromator, comprising the following steps: For the first insert and the second insert arranged sequentially along the direction of the electron beam on a straight section of the synchrotron radiation storage ring, the dual crystal monochromator to be tested is placed on the beam line downstream of the second insert; A movable beam blocker is provided in front of the first crystal of the dual-crystal monochromator to adjust the beam size incident on the first crystal; a detector is provided behind the second crystal of the dual-crystal monochromator. The first insert is closed, and the magnetic gap of the second insert is adjusted to generate probe light that prevents thermal deformation of the first crystal. The detector is used to measure the rocking curves of the second crystal when the probe light is incident on different positions of the first crystal. The angular distribution of the first crystal planes in the heat-deformation-free state is obtained based on the diffraction peak angles of each rocking curve. Then, the height distribution h of the first crystal planes in the heat-deformation-free state is obtained based on the angular distribution of the first crystal planes in the heat-deformation-free state. (x,y)-0 ; The magnetic gap of the first insert is adjusted to gradually increase the thermal load incident on the first crystal. At each adjusted magnetic gap value, the detector is used to record the rocking curve of the second crystal. Based on these rocking curves under the current thermal load, the height distribution h of the first crystal plane under the current thermal load is obtained. (x,y)-i ; By calculating h (x,y)-i - h (x,y)-0 The thermal deformation distribution of the first crystal under the corresponding thermal load is obtained.

2. The method according to claim 1, characterized in that, The detector is a two-dimensional detector. A rocking curve image is obtained using the two-dimensional detector for each magnetic gap value after the first insert is adjusted. The angle distribution of the first crystal plane under the current thermal load is obtained based on the rocking curve image.

3. The method according to claim 1, characterized in that, The detector is a one-dimensional detector. Under each magnetic gap value after the first insert is adjusted, the one-dimensional detector is used to measure the diffraction peak angles corresponding to multiple different positions on the first crystal surface. Then, the angle distribution of the first crystal surface under the current thermal load is calculated based on the peak angles corresponding to multiple different positions on the first crystal surface.

4. The method according to claim 3, characterized in that, A monochromatic light slit is provided downstream of the second crystal. When the one-dimensional detector is used to scan different spatial positions on the surface of the first crystal to obtain the thermal deformation distribution, the spatial position of the beam emitted after the probe light is diffracted by the first crystal is selected through the monochromatic light slit, so as to realize the spatial resolution measurement of different diffraction points on the surface of the first crystal.

5. The method according to claim 4, characterized in that, The horizontal and vertical opening widths of the monochromatic light slit are independently adjustable.

6. The method according to claim 1, characterized in that, The aperture of the beam blocker is continuously adjustable.

7. The method according to claim 1, characterized in that, Taking into account the diffraction flux, energy bandwidth and corresponding dynamic diffraction width of the probe light, the magnetic gap of the second insert is adjusted to generate probe light that prevents thermal deformation of the first crystal.

8. An in-situ testing device for thermal deformation of a synchrotron monochromator, characterized in that, It includes a first insert, a second insert, a beam blocker, a detector, a control system, and a data acquisition system, all arranged sequentially along the direction of the electron beam on a straight section of the synchrotron radiation storage ring. The magnetic gap of the first insert is adjustable, and the output synchrotron radiation power can be controlled by changing the size of the magnetic gap, so as to apply a controllable thermal load to the first crystal of the dual-crystal monochromator under test. The magnetic gap of the second insert is adjustable, which is used to generate probe light that prevents thermal deformation of the first crystal; The beam blocker is disposed downstream of the second insert and upstream of the dual-crystal monochromator under test in the optical path, and is used to adjust the beam size incident on the first crystal; The dual-crystal monochromator is positioned on the beam line downstream of the second insert. The first crystal is used to receive the heating beam generated by the first insert and the probe beam generated by the second insert. The second crystal is used to perform angle scanning on the probe beam after diffraction by the first crystal to achieve the measurement of the rocking curve. The detector is used to record the intensity of diffracted light at different angles of the second crystal, thereby obtaining the rocking curve; The control system and data acquisition system are respectively connected to the magnetic gap driving mechanism of the first insert, the magnetic gap driving mechanism of the second insert, the driving mechanism of the beam blocker, the rotation mechanism of the second crystal, and the detector. They are used to uniformly control the magnetic gap of the first insert, the aperture of the beam blocker, the angle scanning of the second crystal, and synchronously record the diffraction intensity signal of the detector at each scanning angle. The system calculates the angle distribution of the first crystal facets based on the acquired rocking curve data; then, it obtains the height distribution of the first crystal facets based on the angle distribution under no-thermal-deformation conditions; and finally, it calculates the height distribution h of the first crystal facets based on the height distribution h under no-thermal-deformation conditions. (x,y)-0 and the height distribution h of the first crystal plane under the i-th thermal load (x,y)-i The thermal deformation distribution of the first crystal under the i-th thermal load is obtained.

9. The apparatus according to claim 8, characterized in that, When the detector is a two-dimensional detector, a rocking curve image is obtained using the two-dimensional detector for each magnetic gap value after the first insert is adjusted. Then, the angle distribution of the first crystal surface under the current thermal load is calculated based on the peak angles corresponding to multiple different positions on the first crystal surface.

10. The apparatus according to claim 8, characterized in that, The detector is a one-dimensional detector. Under each magnetic gap value after the first insert is adjusted, the one-dimensional detector is used to measure the diffraction peak angles corresponding to multiple different positions on the first crystal surface. Then, the angle distribution of the first crystal surface under the current thermal load is calculated based on the peak angles corresponding to multiple different positions on the first crystal surface. A monochromatic light slit is set downstream of the second crystal. When the one-dimensional detector is used to scan different spatial positions on the surface of the first crystal point by point to obtain the thermal deformation distribution, the spatial position of the probe light beam after diffraction by the first crystal is selected through the monochromatic light slit, so as to realize the spatial resolution measurement of different diffraction points on the surface of the first crystal.

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