Bent crystal on-line collimation method for x-ray absorption spectrometer

Abstract

The application provides a curved crystal online collimation method of an X-ray absorption spectrometer, and belongs to the technical field of material testing.The curved crystal online collimation method of the X-ray absorption spectrometer comprises the following steps: adjusting the incidence angle and diffraction angle of an X-ray source and a detector relative to a curved crystal to a collimation angle; recording a first light spot focused when X-rays emitted by the X-ray source pass through the curved crystal and do not pass through a diaphragm and a second light spot focused when the X-rays pass through the diaphragm by the detector; comparing the second light spot with the first light spot; and adjusting the position and / or pitch of the curved crystal to make the second light spot match the first light spot, so as to complete the collimation of the curved crystal at the collimation angle.The curved crystal online collimation method of the X-ray absorption spectrometer can observe the change of the focused light spot in real time during the online adjustment process, accurately adjust the posture of the curved crystal, find and correct potential problems of the curved crystal when the curved crystal is applied to the X-ray absorption spectrometer, and effectively ensure the testing accuracy of the X-ray absorption spectrometer.

Description

Technical Field

[0001] This invention relates to the field of materials testing technology, specifically to an online collimation method for bent crystals in an X-ray absorption spectrometer. Background Technology

[0002] X-ray absorption spectroscopy is a widely used material characterization technique for detecting elements in materials and characterizing atomic electronic states, types of coordinating atoms, and distances between coordinating atoms. It has important applications in energy and environment, new materials, catalysis, and other fields.

[0003] In X-ray absorption spectrometry, bent crystal elements are used to monochromaticly focus the polychromatic X-rays generated by the X-ray source onto the sample, thus completing the test of the sample under X-rays at the corresponding energy point. Unlike planar light, X-rays incident on the optical element are not diffracted by the crystal surface but by the crystal planes. Therefore, in X-ray absorption spectrometry, the crystal planes of the bent crystal elements are designed with a certain bevel angle. While this allows the incident X-rays to be focused by the bent crystal diffraction, the curved surface of the bent crystal is difficult to collimate and adjust. The angle of the diffracted light exiting the curved crystal still has a certain deviation, requiring collimation of the bent crystal before testing.

[0004] Since offline adjustment methods for bent crystals cannot disclose potential problems when applied to testing systems, and are difficult to meet the usage requirements and positional accuracy of testing systems, an online collimation method for bent crystals in X-ray absorption spectrometers is needed to solve these problems. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides an online collimation method for bent crystals in X-ray absorption spectrometers. This method enables the collimation of bent crystals applied to X-ray absorption spectrometers through online adjustment, thereby solving the technical problem that offline adjustment methods for bent crystals in the prior art cannot disclose the potential problems when the bent crystals are applied to the testing system, and that it is difficult to make the bent crystal adjustment meet the accuracy requirements of the testing system.

[0006] To achieve the above and other related objectives, this invention provides an online collimation method for an X-ray absorption spectrometer using a bent crystal. This online collimation method is applied to an X-ray absorption spectrometer, which includes an X-ray source, a bent crystal, and a detector. X-rays emitted from the X-ray source are focused onto the detector after diffraction by the bent crystal. The online collimation method includes:

[0007] The incident angle and diffraction angle of the X-ray source and detector relative to the curved crystal are adjusted to a collimation angle;

[0008] The detector records the first focused spot of the X-rays emitted by the X-ray source when they do not pass through the aperture after passing through the curved crystal diffraction, and the second focused spot when they pass through the aperture.

[0009] The second light spot is compared with the first light spot, and the position and / or pitch of the bent crystal are adjusted to match the second light spot with the first light spot, so as to complete the collimation of the bent crystal at the collimation angle.

[0010] In one example of the present invention, the step of recording, by the detector, the first focused spot of the X-rays emitted by the X-ray source when they do not pass through the aperture after passing through the curved crystal diffraction, and the second focused spot when they pass through the aperture, includes:

[0011] No aperture is set in the diffraction path of the X-rays, and the detector records the first spot of the X-rays emitted by the X-ray source after passing through the curved crystal diffraction; an aperture is set in the diffraction path of the X-rays, and the detector records the second spot of the X-ray diffracted light after passing through the aperture.

[0012] In one example of the present invention, comparing the second light spot with the first light spot includes comparing the spot size and / or light intensity of the second light spot and the first light spot.

[0013] In one example of the present invention, comparing the second light spot with the first light spot and matching the second light spot with the first light spot by adjusting the position and / or pitch of the bent crystal includes:

[0014] When the size and / or intensity of the second light spot are smaller than that of the first light spot, with the aperture set in the diffraction path, the size and / or intensity of the second light spot are adjusted to the maximum by adjusting the position and / or pitch of the bent crystal, so that the second light spot is adjusted to match the first light spot.

[0015] In one example of the present invention, the second light spot is compared with the first light spot, and the position and / or pitch of the bent crystal are adjusted to match the second light spot with the first light spot, so as to complete the collimation of the bent crystal at the collimation angle, and the method further includes:

[0016] When the size and / or intensity of the second light spot are at their maximum, the aperture is removed from the diffraction path, and the second light spot is compared with the first light spot recorded by the detector after the aperture is removed. If the second light spot and the first light spot coincide, the collimation of the bent crystal at the collimation angle is completed.

[0017] In one example of the present invention, the online collimation method further includes:

[0018] After the curved crystal completes the collimation and focusing of X-rays at one collimation angle, the incident angle and diffraction angle of the X-ray source and detector relative to the curved crystal are adjusted to another collimation angle. The collimation of the curved crystal at other collimation angles is verified by comparing whether the first and second spots of the X-ray diffracted light overlap at the other collimation angle.

[0019] In one example of the present invention, the aperture of the aperture is greater than or equal to the spot size formed by the X-ray diffracted light at the location where the aperture is set.

[0020] In one example of the present invention, the aperture is a slit.

[0021] In one example of the present invention, the collimation angle is the Bragg angle of the X-ray relative to the bent crystal.

[0022] In one example of the invention, the incident angle and diffraction angle of the X-ray source and detector relative to the curved crystal are adjusted along the Rowland circle of the curved crystal.

[0023] This invention discloses an online collimation method for curved crystals in X-ray absorption spectrometers. The method involves recording, in the collimation direction, the first focused spot of the X-rays diffracted by the curved crystal before passing the aperture and the second focused spot after passing the aperture. Using the first spot as a reference, the position and / or pitch of the curved crystal within the X-ray absorption spectrometer are adjusted to make the second spot coincide with the first spot, thus completing the collimation adjustment of the curved crystal in that collimation direction within the X-ray absorption spectrometer. This online collimation method allows for online collimation adjustment of the optical path of the X-rays diffracted and focused by the curved crystal within the X-ray absorption spectrometer. During online adjustment, changes in the focused spot can be observed in real time to precisely adjust the orientation of the curved crystal, thereby identifying and correcting potential problems when using curved crystals in X-ray absorption spectrometers, effectively ensuring the testing accuracy of the X-ray absorption spectrometer. Therefore, this invention effectively overcomes some practical problems in the prior art and has high utilization value and practical significance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic flowchart of an online collimation method for a bent crystal in an X-ray absorption spectrometer, as shown in an example of the present invention.

[0026] Figure 2 This is a flowchart illustrating step S3 in an example of the present invention;

[0027] Figure 3 This is a flowchart illustrating step S4 in an example of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of an X-ray absorption spectrometer in one example of the present invention;

[0029] Figure 5 This is a simplified structural diagram of an online collimated bent crystal for X-ray absorption spectrometer in one example of the present invention.

[0030] Component designation explanation

[0031] 100, X-ray source; 200, curved crystal; 300, detector; 400, first connecting arm; 500, second connecting arm; 510, aperture; 600, guide rail. Detailed Implementation

[0032] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0033] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as part of the scope of the invention.

[0034] Please see Figures 1 to 5 This invention provides an online collimation method for bent crystals in X-ray absorption spectrometers. It enables the collimation of bent crystals applied to X-ray absorption spectrometers through online adjustment, thereby solving the technical problem that offline adjustment methods for bent crystals in the prior art cannot disclose the potential problems when the bent crystals are applied to the testing system, and that it is difficult to make the bent crystal adjustment meet the accuracy requirements of the testing system.

[0035] Please see Figure 1 , Figure 4 and Figure 5The present invention provides an online collimation method for a bent crystal 200 in an X-ray absorption spectrometer. This online collimation method allows for online adjustment of the position and pitch of the bent crystal 200 on the X-ray absorption spectrometer to collimate the diffracted light path focused by the bent crystal 200, so that the X-rays can be focused non-destructively onto the sample and detector 300 in a set direction.

[0036] like Figure 4 and Figure 5 As shown, the X-ray absorption spectrometer includes an X-ray source 100, a curved crystal 200, and a detector 300. In the X-ray absorption spectrometer, the X-ray source 100 and the detector 300 are symmetrically arranged on both sides of the curved crystal 200. The X-ray source 100 emits X-rays along a set incident direction to project the X-rays onto the curved surface of the curved crystal 200. The curved crystal 200 then performs symmetrical diffraction on the incident polychromatic X-rays, so that the monochromatic X-ray diffracted light that conforms to the Bragg angle is diffracted and focused along a symmetrical diffraction path to the detector 300. The X-ray source 100, the curved crystal 200, and the detector 300 are mounted on the guide rail 600. The X-ray source 100 and the detector 300 are symmetrically arranged on both sides of the curved crystal 200 along the Rowland circle. The incident angle and diffraction angle of the X-ray source 100 and the detector 300 relative to the curved crystal 200 can be adjusted by the guide rail 600, so that the X-ray source 100 and the detector 300 are always on the Rowland circle of the curved crystal 200 when the angle is adjusted. Furthermore, a first connecting arm 400 is provided between the fixed positions of the X-ray source 100 and the curved crystal 200, and a second connecting arm 500 is provided between the fixed positions of the detector 300 and the curved crystal 200. The first connecting arm 400 and the second connecting arm 500 are rotatably connected to the fixed positions of the curved crystal 200, so that the X-ray absorption spectrometer can determine the incident light path between the X-ray source 100 and the curved crystal 200 and the diffraction light path between the detector 300 and the curved crystal 200 through the first connecting arm 400 and the second connecting arm 500.

[0037] like Figure 1 As shown, the present invention provides an online collimation method for a bent crystal 200 in an X-ray absorption spectrometer, comprising the following steps:

[0038] S1. Adjust the incident angle and diffraction angle of the X-ray source 100 and detector 300 relative to the curved crystal 200 to a collimation angle;

[0039] In step S1, the incident angle and diffraction angle of X-rays relative to the normal of the curved surface of the curved crystal 200 are determined according to the first connecting arm 400 and the detector 300 and the curved crystal 200. By adjusting the relative positions of the X-ray source 100 and the detector 300 and the curved crystal 200 on the guide rail 600, the incident angle and diffraction angle of the X-ray source 100 and the detector 300 relative to the curved crystal 200 are symmetrically adjusted to a collimation angle so that the curved crystal 200 can be further collimated using X-rays in the X-ray absorption spectrometer.

[0040] Specifically, when adjusting the incident angle and diffraction angle of the X-ray source 100 and detector 300 relative to the curved crystal 200, the relative positions of the X-ray source 100 and detector 300 and the curved crystal 200 are adjusted along the Rowland circle of the curved crystal 200.

[0041] In step S1, the collimation angle to be adjusted is the Bragg diffraction angle when the X-rays are incident and diffracted relative to the bent crystal 200°.

[0042] Next, step S2 is executed, recording the first spot of X-rays emitted by the X-ray source 100 after diffraction by the curved crystal 200 without passing through the aperture 510 and the second spot of X-rays after passing through the aperture 510 through the detector 300.

[0043] like Figure 4 As shown, step S2 includes either not setting an aperture 510 on the second connecting arm 500 that coincides with the X-ray diffraction path, so that the detector 300 records the first spot focused when the X-rays are diffracted by the curved crystal 200 but do not pass through the aperture 510; or, installing an aperture 510 on the second connecting arm 500 that coincides with the X-ray diffraction path, so that the detector 300 records the second spot focused after the X-rays are diffracted by the curved crystal 200 and pass through the aperture 510. When recording the spot information, the detector 300 records the shape, size, and intensity of the cursor.

[0044] In step S2, the aperture of the aperture 510 is greater than or equal to the spot size of the X-ray diffracted light focused at the position of the aperture 510 in the diffraction path, so that the X-rays focused by the bent crystal 200 in the collimated state can pass through the aperture 510 completely without damage. It should be noted that the type of aperture 510 used in this invention is not limited. For example, in one embodiment of this invention, the aperture 510 is a slit.

[0045] Next, step S3 is performed: the second light spot is compared with the first light spot, and the position and / or pitch of the bent crystal 200 are adjusted to match the second light spot with the first light spot, so as to complete the collimation of the bent crystal 200 at the collimation angle.

[0046] In step S3, the second light spot recorded by the detector 300 is compared with the first light spot. When the second light spot and the first light spot cannot match, the position and pitch of the curved crystal 200 can be adjusted by the adjustment mechanism set at the position of the curved crystal 200 on the X-ray spectrometer, so that the second light spot of the X-ray diffracted light after passing through the aperture 510 and focusing gradually coincides with the first light spot that is not focused by the aperture 510, thereby correcting the diffracted light path of the X-ray after diffraction by the curved crystal 200 to the set diffracted light path, and thus completing the collimation adjustment of the curved crystal 200 in this collimation direction.

[0047] In step S3, the second light spot is compared with the first light spot, including comparing the spot size and / or light intensity of the second light spot and the first light spot.

[0048] Specifically, such as Figure 2 As shown, in step S3, the second light spot is compared with the first light spot, and the position and / or pitch of the curved crystal 200 are adjusted to match the second light spot with the first light spot, so as to complete the collimation of the curved crystal 200 at the collimation angle, including the following steps:

[0049] S31. Compare the second light spot recorded by the detector 300 with the first light spot. When the light spot size and / or light intensity of the second light spot is smaller than that of the first light spot, with the aperture 510 set in the diffraction path, adjust the position and / or pitch of the curved crystal 200 to adjust the light spot size and / or light intensity of the second light spot to the maximum so that the second light spot is adjusted to match the first light spot.

[0050] S32. When the size and / or intensity of the second light spot are at their maximum, remove the aperture 510 from the diffraction path and compare whether the second light spot coincides with the first light spot recorded by the detector 300 after removing the aperture 510.

[0051] S33. If the second light spot coincides with the first light spot, the collimation of the bent crystal 200 at the collimation angle is completed; if the second light spot still cannot coincide with the first light spot, repeat steps S31 to S32 until the second light spot focused by the X-ray diffraction light passing through the aperture 510 coincides with the first light spot focused by the light spot not passing through the aperture 510, then the collimation adjustment of the bent crystal 200 in the collimation direction in the X-ray absorption spectrometer is completed.

[0052] Furthermore, in one embodiment of the present invention, the online collimation method of the bent crystal 200 of the X-ray absorption spectrometer further includes step S4: verifying the online collimation of the bent crystal 200 in the X-ray absorption spectrometer.

[0053] Specifically, such as Figure 3As shown, in step S4, the online collimation verification of the bent crystal 200 in the X-ray absorption spectrometer includes the following steps:

[0054] S41. After the X-rays are collimated and focused by the curved crystal 200 at one collimation angle, the incident angle and diffraction angle of the X-ray source 100 and the detector 300 relative to the curved crystal 200 are adjusted to another collimation angle.

[0055] S42. By comparing whether the first and second spots of the X-ray diffraction light overlap at another collimation angle, it can be verified whether the bent crystal 200 is collimated at other collimation angles.

[0056] If the X-ray diffracted light recorded by detector 300 at another collimation angle does not pass through aperture 510 and the first and second light spots focused by aperture 510 are consistent, it indicates that the collimation adjustment of the bent crystal 200 in the X-ray diffractometer is complete.

[0057] In step S4, the other collimation angle adjusted in the verification step is another Bragg angle of the X-ray relative to the bent crystal 200.

[0058] This invention relates to an X-ray absorption spectrometer that uses a first and second detector in the testing system to detect in real time the reference and test light intensities of X-rays before and after transmission through the sample by a spectroscopic element. Based on the reference and test light intensities obtained from scanning at different energy points, the true X-ray absorption spectrum of the sample is calculated. Compared to existing signal acquisition methods, this X-ray absorption spectrometer can simultaneously acquire the reference and test light intensities before and after X-ray transmission through the sample when acquiring the absorption coefficient of a single X-ray energy point, thus saving half the testing time. It also effectively avoids errors caused by fluctuations in light source intensity, stability of the moving mechanism, ambient temperature, vibration, and other factors affecting the acquired spectral data, thereby significantly improving the accuracy and quality of the test spectral data. Therefore, this invention effectively overcomes some practical problems in the prior art and has high utilization value and practical significance.

[0059] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for online collimation of bent crystals in an X-ray absorption spectrometer, characterized in that, The online collimation method is applied to an X-ray absorption spectrometer, which includes an X-ray source, a curved crystal, and a detector. X-rays emitted from the X-ray source are focused onto the detector after diffraction by the curved crystal. The online collimation method includes: The incident angle and diffraction angle of the X-ray source and detector relative to the curved crystal are adjusted to a collimation angle; The detector records the first focused spot of the X-ray emitted by the X-ray source after passing through the curved crystal diffraction without passing through the aperture, and the second focused spot after passing through the aperture; the aperture of the aperture is greater than or equal to the spot size formed by the X-ray diffracted light at the location of the aperture. The second light spot is compared with the first light spot, and the position and / or pitch of the bent crystal are adjusted to match the second light spot with the first light spot, so as to complete the collimation of the bent crystal at the collimation angle. After the curved crystal completes the collimation and focusing of X-rays at one collimation angle, the incident angle and diffraction angle of the X-ray source and detector relative to the curved crystal are adjusted to another collimation angle. The collimation of the curved crystal at other collimation angles is verified by comparing whether the first and second spots of the X-ray diffracted light overlap at the other collimation angle.

2. The online collimation method for bent crystals in an X-ray absorption spectrometer according to claim 1, characterized in that, The recording of the first focused spot of X-rays emitted by the X-ray source after passing through the curved crystal diffraction without passing through the aperture, and the second focused spot after passing through the aperture, by the detector, includes: No aperture is set in the diffraction path of the X-rays, and the detector records the first spot of X-rays emitted by the X-ray source after being focused by the curved crystal diffraction. An aperture is set in the diffraction path of the X-rays, and the detector records the second spot of the X-ray diffracted light after it passes through the aperture.

3. The online collimation method for bent crystals in an X-ray absorption spectrometer according to claim 1, characterized in that, The comparison of the second light spot with the first light spot includes comparing the spot size and / or light intensity of the second light spot and the first light spot.

4. The online collimation method for bent crystals in an X-ray absorption spectrometer according to claim 3, characterized in that, The step of comparing the second light spot with the first light spot and adjusting the position and / or pitch of the bent crystal to match the second light spot with the first light spot includes: When the size and / or intensity of the second light spot are smaller than that of the first light spot, with the aperture set in the diffraction path, the size and / or intensity of the second light spot are adjusted to the maximum by adjusting the position and / or pitch of the bent crystal, so that the second light spot is adjusted to match the first light spot.

5. The online collimation method for bent crystals in an X-ray absorption spectrometer according to claim 4, characterized in that, The step of comparing the second light spot with the first light spot and adjusting the position and / or pitch of the bent crystal to match the second light spot with the first light spot, thereby completing the collimation of the bent crystal at the collimation angle, further includes: When the size and / or intensity of the second light spot are at their maximum, the aperture is removed from the diffraction path, and the second light spot is compared with the first light spot recorded by the detector after the aperture is removed to see if they coincide. If the second light spot coincides with the first light spot, then the collimation of the bent crystal at the collimation angle is completed.

6. The online collimation method for bent crystals in an X-ray absorption spectrometer according to claim 1, characterized in that, The aperture is a slit.

7. The online collimation method for bent crystals in an X-ray absorption spectrometer according to claim 1, characterized in that, The collimation angle is the Bragg angle of the X-ray relative to the bent crystal.

8. The online collimation method for bent crystals in an X-ray absorption spectrometer according to claim 1, characterized in that, The incident angle and diffraction angle of the X-ray source and detector relative to the curved crystal are adjusted along the Rowland circle of the curved crystal.

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