Method for testing chamfer angle and curvature radius of spherical curved crystal
By building a test device and accurately measuring the bevel angle and curvature radius of spherical curved crystals, the problem of insufficient measurement accuracy in the prior art is solved, and the data quality of the X-ray spectrometer is improved.
Patent Information
- Application Number
- CN202410069152.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-17
- Publication Date
- 2025-07-18
AI Technical Summary
In the prior art, the measurement accuracy of the bevel angle and curvature radius of spherical curved crystals is insufficient, and it cannot meet the data quality requirements of the X-ray spectrometer.
By building a test device, the output count rate corresponding to the inclination angle is recorded using the detector to determine the magnitude of the bevel angle, and by synchronously moving the X-ray source and the detector, the curvature radius of the spherical curved crystal is calculated to achieve accurate measurement.
The measurement accuracy of spherical curved crystal bevel angle and curvature radius is improved, and the absorption spectrum acquisition quality of the X-ray spectrometer is ensured.
Smart Images
Figure CN120334259A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of X-ray measurement, and particularly relates to a method for testing the bevel angle and radius of curvature of a spherical bent crystal, which is used to improve the spectrum acquisition accuracy of an X-ray spectrometer. Background Art
[0002] X-ray absorption spectroscopy is one of the important methods for studying the structure of substances and is widely used in many fields such as materials, biology, chemistry, environment, and geology. Laboratory spectrometers are analytical instruments based on the Rowland circle imaging principle, which are composed of components such as an X-ray source, a spherical bent crystal, a detector, and a high-precision displacement stage, and have high requirements for the installation accuracy of each component. Specifically, the laboratory spectrometer uses an energy scanning mechanism to move the X-ray source, the spherical bent crystal, the sample, and the detector according to a certain Rowland circle configuration in order to collect the absorption spectrum of the sample.
[0003] A spherical bent crystal refers to a crystal with a flat back and a spherical front, which plays a role in focusing, reflecting, and dispersing incident X-rays. The bevel angle and radius of curvature of the spherical bent crystal directly affect the relative position relationship of the key components in the instrument on the dynamic Rowland circle. In order to obtain high-quality absorption spectrum data, it is necessary to accurately measure the bevel angle and radius of curvature of the spherical bent crystal.
[0004] The bevel angle of the spherical bent crystal refers to the angle between the normal vector of the crystal plane 101 in the coating of the spherical bent crystal and the normal vector of the glass substrate surface 102, and the radius of curvature of the spherical bent crystal refers to the radius corresponding to the internal crystal plane of the spherical bent crystal. For an X-ray spectrometer, using a spherical bent crystal with a bevel angle of 0 can eliminate the step of measuring the bevel angle, but it is difficult to stably process a spherical bent crystal with a bevel angle of 0 with the current manufacturing process. The bevel angle is an angle that naturally occurs due to the crystal structure during the manufacturing process of the spherical bent crystal. As shown in Figure 1, the size of the bevel angle generated during the manufacturing of the spherical bent crystal is usually in the range of 0.1 - 0.5°, and there will be a certain deviation between the actual value and the theoretical design value of the radius of curvature of the spherical bent crystal.
[0005] Although manufacturers in the prior art will measure the bevel angle and radius of curvature, the accuracy often cannot meet the requirements. During the actual use of the X-ray spectrometer, it is found that there are deviations between the bevel angle and radius of curvature of the crystal and the theoretical design values given by the manufacturer, which cannot meet the quality requirements of the data in spectrum acquisition. Therefore, there is an urgent need for a solution to accurately measure the actual bevel angle and radius of curvature of the spherical bent crystal. Summary of the Invention
[0006] The purpose of the present invention is to provide a method for testing the bevel angle and radius of curvature of a spherical bent crystal to accurately measure the actual bevel angle and radius of curvature of the spherical bent crystal.
[0007] To achieve the above object, the present invention provides a method for testing the bevel angle and the radius of curvature of a spherical bent crystal, including:
[0008] S1: Set up a test device, the test device includes a spherical bent crystal, an X-ray source and a sample stage located on the same Rowland circle, and a detector behind the sample stage. The detector uses a silicon drift detector, and initialize the attitude of the spherical bent crystal;
[0009] S2: Turn on the X-ray source;
[0010] S3: Use the detector to record the OCR corresponding to each first inclination angle θ, and obtain the first inclination angle θ corresponding to the maximum OCR max As the projection of the bevel angle α in the horizontal plane of the Rowland circle; Adjust the crystal attitude adjustment mechanism so that the first inclination angle θ = θ max , use the detector to record the output count rate OCR corresponding to each second inclination angle χ, and obtain the second inclination angle χ corresponding to the maximum OCR max As the projection of the bevel angle α in the plane perpendicular to the Rowland circle;
[0011] S4: Determine the size of the bevel angle α according to the projections of the bevel angle α in the horizontal plane of the Rowland circle and the plane perpendicular to the Rowland circle;
[0012] S5: Remove the sample stage, change the type of the detector to a surface detector, and update the positions of the X-ray source, the spherical bent crystal, and the detector according to the bevel angle α, so that the X-ray source, the spherical bent crystal, and the detector are located on the same Rowland circle;
[0013] S6: Synchronously move the X-ray source and the detector away from each other with the same displacement amount, and at the same time the spherical bent crystal moves to the corresponding position according to the geometric relationship of the Rowland circle. During this process, the diameter R of the Rowland circle continuously increases and the Bragg angle θ B remains unchanged; Determine the position where the width of the focal spot in the horizontal direction on the detector in the plane of the Rowland circle is the smallest, and obtain the object distance and the image distance corresponding to the position where the width of the focal spot in the horizontal direction is the smallest, and calculate the radius of curvature of the spherical bent crystal in the plane of the Rowland circle therefrom, as the actual value of the radius of curvature of the spherical bent crystal.
[0014] The specific steps of S4 include:
[0015] S41: Rotate the clock face angle of the spherical bent crystal by a fixed increment, repeat step S3, and find the projections in the horizontal plane of the Rowland circle and the plane perpendicular to the Rowland circle corresponding to each clock face angle , until the results of all clock face angles are collected;
[0016] S42: For each clock face angle The projections of the corresponding bevel angle α in the plane of the Rowland circle and in the plane perpendicular to the Rowland circle are drawn in the same figure, and the data points are fitted. The radius of the fitted circle is the magnitude of the bevel angle α.
[0017] In the step S4, when the results of all dial angles are all collected, the dial angle rotates a total of 360°.
[0018] The test device includes a base, a spherical bent crystal mounted on the base, an X-ray source and a detector. Among them, the spherical bent crystal is fixed on the base through a crystal attitude adjustment mechanism and a crystal displacement stage, the X-ray source is fixed on the base through an X-ray source displacement stage, and the detector and the sample stage are fixed on the base through a detector displacement stage;
[0019] In the step S1, a test device is built. The test device includes a spherical bent crystal, an X-ray source and a sample stage located on the same Rowland circle, and a detector behind the sample stage. Specifically, it includes: fixing the spherical bent crystal on the crystal attitude adjustment mechanism, finely adjusting the geometric center height of the spherical bent crystal, and keeping the geometric center of the spherical bent crystal in the same plane as the X-ray source, the sample stage and the detector on the Rowland circle; Subsequently, adjust the energy linkage scanning device to move the X-ray source, the sample stage, the spherical bent crystal and the detector to the corresponding positions on the same Rowland circle where the Bragg angle and the Rowland circle diameter meet the requirements.
[0020] In the step S1, move the X-ray source, the spherical bent crystal and the detector to the corresponding positions where the Bragg angle = 80° and the radius of the Rowland circle = 500 mm.
[0021] In the step S6, control the positions of the spherical bent crystal, the X-ray source and the detector by controlling the crystal displacement stage, the X-ray source displacement stage and the detector displacement stage. Furthermore, move the X-ray source and the detector, and at the same time, the spherical bent crystal moves to the corresponding position according to the geometric relationship of the Rowland circle to determine the position where the width of the focal spot in the horizontal direction in the plane of the Rowland circle on the detector is the smallest; Subsequently, obtain the distance from the X-ray source to the center of the spherical bent crystal or the distance from the center of the spherical bent crystal to the center of the detector corresponding to the position where the focal spot width is the smallest as the object distance and the image distance, and calculate the radius of curvature of the spherical bent crystal in the plane of the Rowland circle based on this.
[0022] In the step S1, initialize the attitude of the spherical bent crystal, specifically including: making the numerical values of the first inclination angle θ and the second inclination angle χ of the spherical bent crystal zero, and marking the dial angle at this time as 0°.
[0023] In the step S3, the first inclination angle θ is adjusted within the range of ±0.5°, and the adjustment amount is 0.05° per time. The output count rate OCR corresponding to each first inclination angle θ is recorded, and the first inclination angle θ corresponding to the maximum OCR is found. max , which is denoted as the projection of the bevel angle in the horizontal plane of the Rowland circle.
[0024] In the step S6, according to the formula u = v = Rsinθ B and the object distance u or the image distance v, the Bragg angle θ B is substituted to obtain the radius of curvature R of the spherical bent crystal in the plane of the Rowland circle.
[0025] The method for testing the bevel angle and the radius of curvature of the spherical bent crystal of the present invention standardizes the process of testing the bevel angle and the radius of curvature by changing the posture of the spherical bent crystal and then changing the object distance and the image distance, thereby establishing a more precise linkage position relationship between key components (X-ray source light source point, crystal geometric center, and detector center), and realizing accurate measurement of the actual bevel angle and radius of curvature of the spherical bent crystal to improve the quality of absorption spectrum acquisition. Description of the Drawings
[0026] Figure 1A and Figure 1B are schematic diagrams of the bevel angle of a typical spherical bent crystal, where Figure 1A shows a spherical bent crystal with a bevel angle of 0, Figure 1B shows a spherical bent crystal with a certain bevel angle.
[0027] Figure 2 and Figure 3 are schematic diagrams of the method for testing the bevel angle and the radius of curvature of the spherical bent crystal according to an embodiment of the present invention. Among them, Figure 2 corresponds to Figure 1A the spherical bent crystal with a bevel angle of 0 shown, Figure 3 corresponds to the spherical bent crystal with a bevel angle as shown in Figure 1B .
[0028] Figure 4 is an optical path diagram when the spherical bent crystal, the X-ray source, and the detector are precisely linked according to the Rowland circle configuration to achieve energy scanning within the energy range corresponding to the Bragg angle of 54.5° to 83.5°.
[0029] Figure 5 is a schematic structural diagram of the fixed test device adopted by the method for testing the bevel angle and the radius of curvature of the spherical bent crystal of the present invention.
[0030] Figure 6 is a coordinate axis definition diagram of the spherical bent crystal.
[0031] Figure 7It is a relationship diagram of each first inclination angle and OCR recorded by the test method of the bevel angle and curvature radius of the spherical bent crystal of the present invention.
[0032] Figure 8 It is a fitting result diagram of the bevel angle.
[0033] Figure 9 It is a schematic diagram of the positions of the two focal points of the spherical bent crystal of the present invention.
[0034] Figure 10 It is a spot shape diagram shown at different positions of the surface detector in the outgoing light direction obtained by the test method of the curvature radius of the spherical bent crystal of the present invention.
[0035] Figure 11 It is a schematic diagram of the moving mode when the test method of the bevel angle and curvature radius of the spherical bent crystal of the present invention is at step S6. Specific embodiments
[0036] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0037] The core design idea of the test method of the bevel angle and curvature radius of the spherical bent crystal of the present invention is as follows:
[0038] As Figure 2 shown, the spherical bent crystal to be measured is used as the analyzing crystal 20, and a Rowland circle configuration is formed with the center of the X-ray source 10 and the sample stage 30. The diameter of the Rowland circle corresponds to the curvature radius of the spherical crystal. In the crystal test scheme, when measuring the bevel angle of the spherical bent crystal, no sample needs to be placed on the sample stage 30. The incident light beam emitted by the X-ray source 10 is monochromatized by the spherical bent crystal 20 and received by the detector 40 located behind the sample stage 30. Thus, when measuring the bevel angle, the analyzing crystal 20, the ray source 10 and the sample stage 30 are on the Rowland circle. The detector 40 is behind the sample stage 30. The window of the detector is very close to but does not coincide with the sample stage. When measuring the curvature radius, the detector is replaced with a surface detector, the sample stage 30 is removed, and the crystal 20, the ray source 10 and the surface detector 40 are on the Rowland circle. As shown in FIG. 1 and Figure 3 shown, the angle between the incident light beam and the crystal plane normal is the Bragg angle, and the angle between the crystal surface and the crystal plane normal is the bevel angle.
[0039] The spherical bent crystal 20, the X-ray source 10 and the detector 40 are respectively equipped with high-precision combined displacement stages and are precisely linked according to the Rowland circle geometry configuration. The positions and optical paths of the spherical bent crystal 20, the X-ray source 10 and the detector 40 corresponding to different Bragg angles are as Figure 4 shown, and the optical path needs to satisfy Bragg angle = θB , the Rowland circle diameter = the crystal curvature radius = R, the distance from the ray source to the crystal = the distance from the crystal to the detector = Rsinθ B . The present invention adjusts the crystal attitude and the optical path to measure the crystal bevel angle and the curvature radius.
[0040] As Figure 5 shown is the fixed test device adopted by the test method for the bevel angle and the curvature radius of the spherical bent crystal of the present invention. As Figure 5 shown, the test device includes a base 100, a spherical bent crystal 20 mounted on the base 100 and located on the same Rowland circle, an X-ray source 10 and a detector 40. Among them, the spherical bent crystal 20 is fixed on the base 100 through a crystal attitude adjustment mechanism 21 and a crystal displacement stage 22, the X-ray source 10 is fixed on the base 100 through an X-ray source displacement stage 11, and the detector 40 and the sample stage 30 are fixed on the base 100 through a detector displacement stage 41. The coordinate axes of the spherical bent crystal are defined as Figure 6 shown, is the clock face angle, that is, the direction rotation angle of the crystal, θ is the first inclination angle, that is, the inclination angle in the Rowland circle plane, χ is the second inclination angle, the inclination angle perpendicular to the Rowland circle plane. The first inclination angle θ and the second inclination angle χ are respectively the projections of the bevel angle α in the Rowland circle plane and in the plane perpendicular to the Rowland circle. The X-ray source displacement stage 11, the crystal displacement stage 22 and the detector displacement stage 41 form an energy linkage scanning device.
[0041] The test method for the bevel angle and the curvature radius of the spherical bent crystal of the present invention includes the following steps:
[0042] Step S1: Build a test device. The test device includes a spherical bent crystal 20, an X-ray source 10 and a sample stage 30 located on the same Rowland circle, and a detector 40 located behind the sample stage 30. The detector 40 uses a silicon drift detector SDD, and initialize the attitude of the spherical bent crystal 20;
[0043] In the step S1, build a test device. The test device includes a spherical bent crystal 20, an X-ray source 10 and a sample stage 30 located on the same Rowland circle, and a detector 40 located behind the sample stage 30. Specifically, it includes: as Figure 6 shown, fix the spherical bent crystal 20 on the crystal attitude adjustment mechanism 21, and finely adjust the geometric center height of the spherical bent crystal 20 (that is, finely adjust along the Figure 6 z-axis in it), and keep the geometric center of the spherical bent crystal 20 in the same plane of the Rowland circle as the X-ray source 10, the sample stage 30 and the detector 40; Subsequently, adjust the energy linkage scanning device so that the X-ray source 10, the sample stage 30, the spherical bent crystal 20 and the detector 40 are respectively moved to the positions corresponding to the requirements that the Bragg angle and the Rowland circle diameter are satisfied and located on the same Rowland circle.
[0044] In this embodiment, the energy-linked scanning device is adjusted so that the X-ray source 10, the spherical bent crystal 20, and the detector 40 are respectively moved to the positions corresponding to the Bragg angle = 80° and the Rowland circle radius = 500 mm (which is the theoretical curvature radius value).
[0045] In the step S1, the diameter of the Rowland circle is the theoretical value of the curvature radius of the spherical bent crystal 20. The theoretical value of the curvature radius will be marked on the spherical bent crystal during processing. In this embodiment, the laboratory spectrometers are all designed based on the Rowland circle diameter = 500 mm, so the crystals purchased all have a theoretical curvature radius value of the spherical bent crystal = 500 mm. The Rowland circle diameter is also set to 500 mm. However, there is a deviation between the actual curvature radius of the crystal and 500 mm, so the curvature radius needs to be measured in the subsequent steps.
[0046] In the step S1, the attitude of the spherical bent crystal 20 is initialized, which specifically includes: adjusting the crystal attitude adjustment mechanism 21 so that the values of the first inclination angle θ and the second inclination angle χ of the spherical bent crystal 20 are zero, and marking the clock face angle at this time as 0°.
[0047] Step S2: Turn on the X-ray source 10;
[0048] Step S3: Use the detector 40 to record the OCR corresponding to each first inclination angle θ, and obtain the first inclination angle θ corresponding to the maximum OCR max as the projection of the bevel angle α in the horizontal plane of the Rowland circle; adjust the crystal attitude adjustment mechanism so that the first inclination angle θ = θ max , use the detector 40 to record the output count rate OCR corresponding to each second inclination angle χ, and obtain the second inclination angle χ corresponding to the maximum OCR max as the projection of the bevel angle α in the plane perpendicular to the Rowland circle;
[0049] Thus, the detector control software displays the output count rate OCR at this time. The first inclination angle θ max and the second inclination angle χ max corresponding to the maximum OCR are the projections of the bevel angle α in the horizontal plane of the Rowland circle and in the plane perpendicular to the Rowland circle at this time.
[0050] The size of the bevel angle α is usually in the range of 0.1 - 0.5°. Due to the randomness of placing the crystal, the direction of the bevel angle α cannot be determined, and the size of the bevel angle needs to be determined within the range of ±0.5°. Therefore, in the step S2, the first inclination angle θ is adjusted within the range of ±0.5°, the adjustment amount is 0.05° per time, the output count rate OCR corresponding to each first inclination angle θ is recorded, and the first inclination angle θ corresponding to the maximum OCR is found max, denoted as the projection of the bevel angle in the horizontal plane of the Rowland circle. The obtained results are as Figure 7 shown.
[0051] Similarly, in the said step S2, adjust the crystal attitude adjustment mechanism to make the first inclination angle θ = θ max , and use the same method to find the second inclination angle χ max corresponding to the maximum OCR.
[0052] Step S4: Determine the size of the bevel angle α according to the projections of the bevel angle α in the horizontal plane of the Rowland circle and in the plane perpendicular to the Rowland circle;
[0053] The said step S4 specifically includes:
[0054] Step S41: As Figure 8 shown, rotate the dial angle of the spherical bent crystal 20 by a fixed increment (for example, 10°), repeat the above step S3, and find the projections in the horizontal plane of the Rowland circle and in the plane perpendicular to the Rowland circle corresponding to each dial angle (i.e., θ max and χ max ), until the results of all dial angles are collected;
[0055] In the said step S41, when the results of all dial angles are collected, the dial angle rotates a total of 360°.
[0056] Step S42: Plot the projections of the bevel angle α corresponding to each dial angle in the horizontal plane of the Rowland circle and in the plane perpendicular to the Rowland circle (i.e., θ max and χ max ) in the same graph, and perform fitting on the data points. The radius of the fitted circle is the size of the bevel angle α.
[0057] Thus, taking Figure 8 as an example, the crystal dial angle rotates 10° for one data point, with a total of 36 data points, and the crystal dial angle rotates a total of 360°. To ensure the accuracy of the finally fitted result, it is necessary to rotate a total of 360°. At this time, the fitted circle is shown by the dashed line in Figure 8 .
[0058] Thus, through the above steps S1 - step S4, the measurement of the bevel angle α is realized.
[0059] Step S5: Remove the sample stage 30, change the type of the detector 40 to an area detector, and update the positions of the X-ray source 10, the spherical bent crystal 20, and the detector 40 according to the bevel angle α, so that the X-ray source 10, the spherical bent crystal 20, and the detector 40 are located on the same Rowland circle;
[0060] Updating the positions of the X-ray source 10, the spherical bent crystal 20, and the detector 40 according to the bevel angle α specifically includes: adjusting the energy linkage scanning device according to the bevel angle α to move the X-ray source 10, the spherical bent crystal 20, and the detector 40 to the positions corresponding to the requirements that they are located on the same Rowland circle and the Bragg angle and the diameter of the Rowland circle are satisfied.
[0061] In this embodiment, adjust the energy linkage scanning device to move the X-ray source, the spherical bent crystal 20, and the detector to the positions corresponding to the Bragg angle = 80° (including the measured bevel angle α) and the Rowland circle radius = 500 mm (which is the theoretical curvature radius value).
[0062] Step S6: As Figure 11 shown, move the X-ray source 10 and the detector 40 synchronously with the same displacement amount to move them away from each other, and at the same time, the spherical bent crystal 20 moves to the corresponding position according to the Rowland circle geometric relationship. During this process, the diameter R of the Rowland circle continuously increases and the Bragg angle θ B remains unchanged, and determine the position where the width in the horizontal direction of the focal spot in the Rowland circle plane on the detector 40 is the smallest; subsequently, obtain the distance value between the X-ray source 10 and the center of the spherical bent crystal 20 (i.e., the object distance) or the distance between the center of the spherical bent crystal 20 and the center of the detector 40 (i.e., the image distance) corresponding to the position where the width in the horizontal direction of the focal spot is the smallest as the object distance and the image distance, and calculate the curvature radius of the spherical bent crystal in the Rowland circle plane based on this as the actual value of the curvature radius of the spherical bent crystal.
[0063] Among them, the Rowland circle geometric relationship includes:
[0064] 1) The Bragg angle θ B , is the angle between the spherical bent crystal 20 and the incident light (as Figure 2 shown)
[0065] 2) The Rowland circle diameter R, which is the size of the Rowland circle
[0066] 3) The distance between the X-ray source and the crystal = Rsinθ B .
[0067] In the test scheme of step S6, θ B remains unchanged, and the value of sinθ B is fixed. Therefore, the distance Rsinθ between the X-ray source and the crystal B changes with the change of R.
[0068] In an actual test device, such as Figure 4 Figure 5 shown, the displacement stage below the crystal and the displacement stage below the detector / X-ray source are at a 90° angle. The crystal moves in the y direction, and the detector / X-ray source moves in the x direction. To change the Rowland circle radius R, the three components of the X-ray source, crystal, and detector need to be moved to their corresponding positions simultaneously according to the Rowland circle geometry.
[0069] Figure 11 shows the positions of the three components when the Rowland circle diameter = R1 and the positions of the three components when the Rowland circle = R2. When the Rowland circle becomes larger, i.e., R2 becomes R1, the displacement stages of the detector and the X-ray source move away from each other in the x-axis direction, and the displacement stage of the crystal moves away from the center of the circle in the y-axis direction. The displacement amounts of the three components, namely the X-ray source 10, the detector 40, and the spherical bent crystal 20, can be calculated based on the Rowland circle geometry.
[0070] In the step S6, the movement of the X-ray source 10, the detector 40, and the spherical bent crystal 20 starts from the position corresponding to the Rowland circle diameter = 490 mm; correspondingly, when the X-ray source 10, the detector 40, and the spherical bent crystal 20 move to the position corresponding to the Rowland circle diameter = 510 mm, the movement stops, and the change in the width of the focal spot in the horizontal direction in the Rowland circle plane on the detector 40 is recorded and compared during this process to determine the position where the width of the focal spot in the horizontal direction in the Rowland circle plane on the detector is the smallest.
[0071] As Figure 9 shown, since the spherical bent crystal has a focal length in both the Rowland circle plane and the plane perpendicular to the Rowland circle, and the values of the two focal lengths are different. When the positions of other components remain unchanged and the detector 40 is moved back and forth (moving back and forth means the detector 40 moves along the propagation direction of the outgoing light), the changes in the size and shape of the light spot on the area detector should be as Figure 10 shown. In Figure 10 , the position where the width of the focal spot in the horizontal direction is the smallest and the position where the height of the focal spot in the vertical direction is the smallest do not occur at the same location. That is to say, a spherical bent crystal has two radii of curvature, one is the radius of curvature of the spherical bent crystal in the Rowland circle plane (deduced from the position corresponding to the smallest width of the focal spot in the horizontal direction), and the other is the radius of curvature of the spherical bent crystal in the plane perpendicular to the Rowland circle (deduced from the position corresponding to the smallest height of the focal spot in the vertical direction).
[0072] Considering that the radius of curvature of the spherical bent crystal of the present invention is used in the energy scanning linkage after being obtained, and the radius of curvature adopted by the X-ray absorption spectrometer during the energy scanning linkage is the radius of curvature of the spherical bent crystal in the Rowland circle plane, rather than the radius of curvature of the spherical bent crystal in the plane perpendicular to the Rowland circle. Therefore, in this embodiment, the present invention needs to calculate the size of the focal length f through the object distance, and obtain the radius of curvature of the spherical bent crystal in the Rowland circle plane as the actual value of the radius of curvature of the spherical bent crystal.
[0073] As Figure 5 shown, the test device includes a base 100, a spherical bent crystal 20 mounted on the base 100 and located on the same Rowland circle, an X-ray source 10, and a detector 40. Among them, the spherical bent crystal 20 is fixed on the base 100 through a crystal attitude adjustment mechanism 21 and a crystal displacement stage 22, the X-ray source 10 is fixed on the base 100 through an X-ray source displacement stage 11, the detector 40 is fixed together with the sample stage 30 and fixed on the base 100 through a detector displacement stage 41. Therefore, by controlling the crystal displacement stage 22, the X-ray source displacement stage 11, and the detector displacement stage 41, the positions of the spherical bent crystal 20, the X-ray source 10, and the detector 40 can be controlled, so as to move the X-ray source and the detector. At the same time, the spherical bent crystal moves to the corresponding position according to the Rowland circle geometric relationship. Since the positional relationship among the three points of the spherical bent crystal 20, the X-ray source 10, and the detector 40 is determined by the Rowland circle geometric configuration and a starting position is required, it can start with the diameter of the Rowland circle being 490 mm and then move on this basis.
[0074] The radius of curvature R of the spherical bent crystal 20 in the Rowland circle plane satisfies the following formula:
[0075]
[0076]
[0077] Among them, the object distance u is the distance between the X-ray source 10 and the spherical bent crystal 20, the image distance v is the distance between the spherical bent crystal 20 and the detector 40, the object distance and the image distance are equal, and θ B is the Bragg angle, and f is the focal length in the horizontal direction.
[0078] Therefore, when the spot on the detector 40 is the smallest, the object distance u = image distance v = Rsinθ B .
[0079] According to the formula u = v = Rsinθ B and the object distance / image distance, substituting the size of the Bragg angle θ B can obtain the radius of curvature R of the spherical bent crystal 20 in the Rowland circle plane.
[0080] The test method for the bevel angle and radius of curvature of the spherical bent crystal of the present invention standardizes the process of testing the bevel angle and radius of curvature by changing the attitude of the spherical bent crystal and then changing the object distance and image distance, realizes the accurate measurement of the actual bevel angle and radius of curvature of the spherical bent crystal, and further establishes a more accurate linkage position relationship among key components (X-ray source light source point, crystal geometric center and detector center) to improve the absorption spectrum acquisition quality.
[0081] The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Various changes can be made to the above embodiments of the present invention. All simple, equivalent changes and modifications made according to the claims and the content of the specification of the present invention application fall within the scope of the claims of the present invention patent. Those not described in detail in the present invention are all conventional technical contents.
Claims
1. A testing method for the bevel angle and curvature radius of a spherical bent crystal, characterized in that, Including: Step S1: Set up a test device, the test device includes a spherical bent crystal, an X-ray source and a sample stage located on the same Rowland circle, and a detector behind the sample stage. The detector uses a silicon drift detector, and initialize the attitude of the spherical bent crystal; Step S2: Turn on the X-ray source; Step S3: Use a detector to record the OCR corresponding to each first inclination angle θ, and obtain the first inclination angle θ corresponding to the maximum OCR. max As the projection of the bevel angle α in the horizontal plane of the Rowland circle; adjust the crystal attitude adjustment mechanism so that the first inclination angle θ = θ max , use a detector to record the output count rate OCR corresponding to each second inclination angle χ, and obtain the second inclination angle χ corresponding to the maximum OCR. max As the projection of the bevel angle α in the plane perpendicular to the Rowland circle; Step S4: Determine the magnitude of the bevel angle α according to the projections of the bevel angle α in the horizontal plane of the Rowland circle and in the plane perpendicular to the Rowland circle; Step S5: Remove the sample stage, change the type of the detector to a planar detector, and update the positions of the X-ray source, the spherical bent crystal, and the detector according to the bevel angle α, so that the X-ray source, the spherical bent crystal, and the detector are located on the same Rowland circle; Step S6: Synchronously move the X-ray source and the detector by the same displacement amount to move them away from each other. At the same time, the spherical bent crystal moves to the corresponding position according to the Rowland circle geometry. During this process, the diameter R of the Rowland circle keeps increasing and the Bragg angle θ B remains unchanged; determine the position where the width of the focal spot in the horizontal direction on the detector within the Rowland circle plane is the smallest, obtain the object distance and the image distance corresponding to the position where the width of the focal spot in the horizontal direction is the smallest, and calculate the curvature radius of the spherical bent crystal in the Rowland circle plane therefrom as the actual value of the curvature radius of the spherical bent crystal.
2. The method for testing the bevel angle and radius of curvature of a spherical bent crystal according to claim 1, characterized in that, The specific steps of Step S4 include: Step S41: Rotate the clock angle φ of the spherical bent crystal by a fixed increment, repeat Step S3, and find the projections of each clock angle φ in the horizontal plane of the Rowland circle and in the plane perpendicular to the Rowland circle until the results of all clock angles φ are collected; Step S42: Plot the projections of the bevel angle α corresponding to each clock angle φ in the horizontal plane of the Rowland circle and in the plane perpendicular to the Rowland circle in the same graph, and fit the data points. The radius of the fitted circle is the magnitude of the bevel angle α.
3. The method for testing the bevel angle and curvature radius of the spherical bent crystal according to claim 2, wherein In Step S4, when the results of all clock angles φ are collected, the clock angle φ rotates a total of 360°.
4. The method for testing the bevel angle and radius of curvature of the spherical bent crystal according to claim 1, wherein The test device includes a base, a spherical bent crystal, an X-ray source, and a detector installed on the base. Among them, the spherical bent crystal is fixed on the base through a crystal attitude adjustment mechanism and a crystal displacement stage, the X-ray source is fixed on the base through an X-ray source displacement stage, and the detector and the sample stage are fixed on the base through a detector displacement stage; In Step S1, set up a test device, the test device includes a spherical bent crystal, an X-ray source and a sample stage located on the same Rowland circle, and a detector behind the sample stage. Specifically, it includes: fixing the spherical bent crystal on the crystal attitude adjustment mechanism, finely adjusting the height of the geometric center of the spherical bent crystal, and keeping the geometric center of the spherical bent crystal in the same plane as the X-ray source, the sample stage, and the detector on the Rowland circle; Subsequently, adjust the energy linkage scanning device so that the X-ray source, the sample stage, the spherical bent crystal, and the detector are respectively moved to the positions corresponding to the Bragg angle and the Rowland circle diameter meeting the requirements on the same Rowland circle.
5. The method for testing the bevel angle and radius of curvature of the spherical bent crystal according to claim 4, characterized in that, In Step S1, move the X-ray source, the spherical bent crystal, and the detector to the positions corresponding to the Bragg angle = 80° and the Rowland circle radius = 500 mm respectively.
6. The method for testing the bevel angle and radius of curvature of the spherical bent crystal according to claim 4, characterized in that, In Step S6, control the positions of the spherical bent crystal, the X-ray source, and the detector by controlling the crystal displacement stage, the X-ray source displacement stage, and the detector displacement stage, so that the X-ray source and the detector move, and at the same time the spherical bent crystal moves to the corresponding position according to the geometric relationship of the Rowland circle to determine the position where the width of the focal spot in the horizontal direction in the plane of the Rowland circle on the detector is the smallest; Subsequently, obtain the distance from the X-ray source to the center of the spherical bent crystal or the distance from the center of the spherical bent crystal to the center of the detector corresponding to the position where the focal spot width is the smallest as the object distance and the image distance, and calculate the radius of curvature of the spherical bent crystal in the plane of the Rowland circle accordingly.
7. The method for testing the bevel angle and radius of curvature of the spherical bent crystal according to claim 1, wherein In the step S1, the attitude of the spherical bent crystal is initialized, specifically including: setting the values of the first inclination angle θ and the second inclination angle χ of the spherical bent crystal to zero, and marking the clock face angle φ at this time as 0°.
8. The method for testing the bevel angle and radius of curvature of the spherical bent crystal according to claim 1, wherein, In the step S3, the first inclination angle θ is adjusted within the range of ±0.5°, and the adjustment amount is 0.05° per time. The output count rate OCR corresponding to each first inclination angle θ is recorded, and the first inclination angle θ corresponding to the maximum value of OCR is found max , which is denoted as the projection of the bevel angle on the horizontal plane of the Rowland circle.
9. The method for testing the bevel angle and radius of curvature of a spherical bent crystal according to claim 1, characterized in that, In the step S6, according to the formula u = v = Rsinθ B and the object distance u or the image distance v, substitute the Bragg angle θ B to obtain the curvature radius R of the spherical bent crystal in the Rowland circle plane.