Absolute detection device and method for second-order term of x-ray plane mirror surface shape

Abstract

This invention discloses an absolute measurement device and method for the second-order term of the surface shape of an X-ray plane mirror. The device includes a clamping platform, an interferometer, and a rotating stage. The rotating stage has a rotatable mounting platform for the mirror under test and a reference mirror mounting plate. The mounting platform is positioned in front of the interferometer's plane lens to fix the X-ray plane mirror under test. The reference mirror mounting plate has a mounting platform for a reference mirror, on which a reference plane mirror is mounted. The reference plane mirror reflects the light reflected from the X-ray plane mirror under test back to the interferometer's plane lens to measure the surface shape of the mirror. This invention aims to achieve high-precision absolute measurement of the second-order term surface shape of an X-ray plane mirror, improve measurement accuracy, and provide guiding surface shape measurement results for the manufacturing of high-precision X-ray plane mirrors.

Description

Technical Field

[0001] This invention relates to the field of optical measurement technology, specifically to a device and method for absolute detection of the second term of the surface shape of an X-ray plane mirror. Background Technology

[0002] With the development of advanced light sources such as synchrotron radiation sources and free-electron lasers, the requirements for the surface accuracy of X-ray curved mirrors are becoming increasingly stringent. X-rays have extremely short wavelengths and are often grazing-incidence (reflection angle close to 90°), requiring mirrors to be designed with a long and narrow shape to avoid beam obstruction and maintain brightness. Although a small incident angle can mitigate surface errors to some extent, the inherent high spatial and temporal coherence of the beam (especially free-electron lasers) significantly amplifies any surface distortion, severely affecting beam propagation, focusing quality, and the final experimental results. To meet the demanding requirements of higher intensity and faster repetition rates of next-generation light sources, the fabrication of high-precision X-ray optics is crucial. Current solutions often use one or more grazing-incidence mirrors to guide the beam. The surface accuracy requirements for a single mirror are extremely high; for example, the peak-to-valley error (PV) needs to be controlled within 2 nm, and the root mean square slope error (RMS) needs to be below 50 nrad. Achieving this nanometer-level precision relies on deterministic shaping processes such as elastic emission processing and ion beam polishing, and high-precision surface measurement technology is key to guiding these processes.

[0003] Currently, the mainstream wavefront stitching interferometry technique is a relative measurement, and its result is the deviation of the measured surface shape relative to the reference surface shape. When the accuracy requirement of the measured surface exceeds that of the reference surface, an absolute measurement method must be used. Existing absolute measurement methods have limitations: the three-plate method requires measuring three plates and performing complex rotation comparisons. For large-sized plates, the rotation operation is not only technically difficult, but the deformation caused by gravity also limits the measurement accuracy; another method, the displacement difference method, only requires a plane mirror and a test mirror, and combines small displacements and multiple measurements with fast Fourier transform processing, but its reconstruction result is "quasi-absolute" and cannot recover the second-order terms of the surface (such as spherical and astigmatic terms). Since the radius of curvature (second-order term) is particularly critical to the performance of next-generation X-ray optical devices, how to achieve absolute surface shape measurement containing complete second-order terms has become a core problem that urgently needs to be solved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an absolute detection device and method for the second-order term surface shape of an X-ray plane mirror, which aims to achieve high-precision absolute measurement of the second-order term surface shape of an X-ray plane mirror, improve measurement accuracy, and provide guiding surface shape measurement results for the processing and manufacturing of high-precision X-ray plane mirrors.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] An absolute detection device for the second term of the surface shape of an X-ray plane mirror includes a clamping platform. An interferometer and a rotating stage are fixedly positioned on the clamping platform. The rotating stage has a test mirror clamping platform and a reference mirror clamping connecting plate that can rotate around the rotation axis of the rotating stage. The test mirror clamping platform is arranged in front of the plane lens of the interferometer to fix the X-ray plane mirror under test. The reference mirror clamping connecting plate has a reference mirror clamping platform, on which a reference plane mirror is mounted. The reference plane mirror is used to reflect the light reflected from the X-ray plane mirror under test back to the plane lens of the interferometer, following the rotation of the reference mirror clamping platform and the reference mirror clamping connecting plate, thereby realizing the surface shape measurement of the X-ray plane mirror under test.

[0007] Optionally, the centers of the X-ray plane mirror under test and the reference plane mirror are located at the same horizontal height.

[0008] Optionally, the field of view of the X-ray plane mirror under test is located at the center of the circular field of view of the plane lens of the interferometer.

[0009] Optionally, the reference plane mirror is an X-ray plane mirror or a plane mirror lens, and the lateral dimension of the reference plane mirror is not shorter than the lens diameter of the plane lens of the interferometer.

[0010] Furthermore, the present invention also provides a method for applying the aforementioned X-ray planar reflector surface shape second-order absolute detection device, comprising the following steps:

[0011] S001: Attach a non-reflective light-blocking sheet to the reference plane mirror as a marker point;

[0012] S002: Place the reference plane mirror on the reference mirror mounting stage and measure the surface shape of the reference plane mirror using an interferometer;

[0013] S003: Place the X-ray plane mirror to be tested on the test mirror mounting stage, adjust the angles of the test mirror mounting stage and the reference mirror mounting stage, align with the marked points, and measure the full aperture surface shape of the X-ray plane mirror to be tested compressed along the meridional direction.

[0014] S004: Calculate the second-order absolute surface shape of the X-ray plane mirror under test based on the surface shape of the reference plane mirror and the full aperture surface shape of the X-ray plane mirror under test compressed along the meridional direction.

[0015] Optionally, step S002, measuring the surface shape of the reference plane mirror using an interferometer, includes:

[0016] S101: Adjust the angle of the reference mirror mounting stage so that the fringes of the reference plane mirror in the interferometer are adjusted to the zero-fringe state;

[0017] S102: Use an interferometer to continuously measure the reference plane mirror and collect multiple sets of surface shape data of the reference plane mirror;

[0018] S103: Among the multiple sets of surface shape data of the reference plane mirror, select the result with the best continuous measurement repeatability as the final surface shape of the reference plane mirror.

[0019] Optionally, step S003, which involves aligning and measuring the full aperture surface shape of the X-ray plane mirror under test, compressed along the meridional direction, according to the marked points, includes:

[0020] S201: Rotate the stage of the mirror under test so that the parallel beam of the interferometer completely covers the X-ray plane mirror under test;

[0021] S202: Rotate the reference mirror mounting stage to make the returned light spot appear in the spot diagram of the interferometer measurement software;

[0022] S203: Adjust the angle of the reference mirror stage to position the returned light spot at the center of the interferometer's CCD and adjust the fringes to a zero-fringe state;

[0023] S204: Move the position of the reference mirror mounting stage so that the marker point appears in the area being measured, and make the centroid of the marker point consistent with the ordinate of the centroid of the marker point in the surface shape of the reference plane mirror;

[0024] S205: Jump to step S203 until the condition that the zero stripe and the vertical coordinate of the marker point are consistent is met simultaneously.

[0025] S206: Use an interferometer to perform continuous measurements and collect multiple sets of surface shape data of the X-ray plane mirror under test;

[0026] S207: Among multiple sets of surface shape data of the X-ray plane mirror under test, the result with the best continuous measurement repeatability is selected as the full aperture surface shape of the X-ray plane mirror under test compressed along the meridional direction.

[0027] Optionally, the calculation of the coordinates of the centroid of the marker point includes:

[0028] S301: Use a rectangle to cut out the data of the marked point area, so that only the marked point area has null value NaN data in the cut-out area, set the null value NaN data in the area to 1, and set the other non-numeric NaN data to 0.

[0029] S302: Collect all satisfied... Point location , denoted as set ,in It represents the total number of points set to 1. Point position Data, For any number k A point set to 1;

[0030] S303: Set Calculate the centroid coordinates using the following formula:

[0031] , ;

[0032] in, , These are the x and y coordinates of the centroid of the marker point, respectively, in units of a single pixel.

[0033] Optionally, the calculation of the second-order absolute surface shape of the X-ray plane mirror under test in step S004 includes:

[0034] S401: Perform point-to-point subtraction between the surface shape of the reference plane mirror and the full-aperture surface shape of the X-ray plane mirror under test, compressed along the meridional direction, to obtain the subtracted surface shape height result matrix. ;

[0035] S402: Based on the projected pixel size and the actual surface size, obtain the relative angle between the X-ray mirror under test and the interferometer beam. Calculate the difference between these relative angles to obtain the surface height matrix. The surface error matrix is ​​obtained by scaling up the model. ;

[0036] S403: Based on the actual physical dimensions of the X-ray plane mirror under test and the pixel dimensions obtained from the interferometer measurement results, calculate the scaling factors for the horizontal and vertical coordinates. Then, scale the horizontal dimensions of the horizontal and vertical coordinate matrices in the interferometer measurement results to obtain the scaled horizontal coordinate matrix. and ordinate matrix ;

[0037] S404: Magnified surface error matrix extracted along the meridian of the X-ray reflecting mirror under test. Combined with the scaled x-coordinate matrix Obtain the center intercept And using a quadratic polynomial Fitting center cutoff ;

[0038] S405: Based on the quadratic polynomial The second-order radius of curvature of the X-ray plane mirror under test is obtained. The absolute surface shape of the second-order term is used as the plane mirror of the X-ray being measured.

[0039] Optionally, in step S404, the quadratic polynomial The function expression is:

[0040] ;

[0041] in, They are quadratic polynomials The coefficients of the quadratic term, the linear term, and the constant term are given, and a quadratic polynomial is used. Fitting center cutoff The objective is to fit a second-order polynomial. Intercepting the center line Overall deviation sum of squares Minimize; the second-order radius of curvature of the X-ray plane mirror under test. The expression for the computation function is: ,in For a quadratic polynomial The coefficient of the quadratic term.

[0042] Compared with existing technologies, the present invention mainly achieves the following beneficial effects: The X-ray plane mirror surface shape second-order absolute detection device of the present invention can realize the measurement of the second-order absolute surface shape of X-ray plane mirrors, solving the problems of poor flexibility and insufficient accuracy in traditional measurement methods. The present invention can improve the accuracy and flexibility of the absolute measurement of the second-order surface shape of X-ray plane mirrors, achieving high-precision absolute measurement of the second-order surface shape of X-ray plane mirrors, improving measurement accuracy, and providing guiding surface shape measurement results for the processing and manufacturing of high-precision X-ray plane mirrors, especially suitable for the surface shape measurement and manufacturing of X-ray plane mirrors. Compared with traditional methods, the application method of the X-ray plane mirror surface shape second-order absolute detection device of the present invention not only avoids the cumbersome operation of multiple measurements using the three-plate method, but also achieves high-precision alignment through pixel-level marker point feature extraction, providing more accurate measurement results, and has significant theoretical value and application prospects. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the device structure in an embodiment of the present invention.

[0044] Figure 2 This is a schematic diagram of the basic process of applying the device in an embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of the first measurement position in an embodiment of the present invention.

[0046] Figure 4This is a schematic diagram of the second measurement position in an embodiment of the present invention.

[0047] Figure 5 This is a detailed flowchart of the alignment process in an embodiment of the present invention.

[0048] Figure 6 This is the first measured surface shape diagram in an embodiment of the present invention.

[0049] Figure 7 This is the second measurement surface diagram in an embodiment of the present invention.

[0050] Figure 8 A point-to-point difference map is generated for the surface shape in the embodiments of the present invention.

[0051] Figure 9 This is a second-order polynomial fitting curve of the center intercept in an embodiment of the present invention.

[0052] Legend: 101, clamping platform; 102, interferometer; 103, plane lens; 201, X-ray plane mirror under test; 202, clamping stage for the mirror under test; 203, rotating stage; 301, clamping connecting plate for the reference mirror; 302, clamping stage for the reference mirror; 303, reference plane mirror. Detailed Implementation

[0053] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] like Figure 1As shown, the X-ray plane mirror surface shape second-order absolute detection device of this embodiment includes a clamping stage 101. An interferometer 102 and a rotating stage 203 are fixedly mounted on the surface of the clamping stage 101. The rotating stage 203 is equipped with a test mirror clamping platform 202 and a reference mirror clamping connecting plate 301 that can rotate around the rotation axis of the rotating stage 203. The test mirror clamping platform 202 is arranged in front of the plane lens 103 of the interferometer 102 to fix the X-ray plane mirror under test. The reflector 201 is provided, and a reference mirror clamping stage 302 is provided on the reference mirror clamping connecting plate 301. A reference plane reflector 303 is mounted on the reference mirror clamping stage 302. The reference plane reflector 303 is used to reflect the light reflected from the X-ray plane reflector 201 under test back to the plane lens 103 of the interferometer 102 as the reference mirror clamping stage 302 rotates with the reference mirror clamping connecting plate 301, so as to realize the surface shape measurement of the X-ray plane reflector 201 under test. The interferometer 102 can be a Fizeau interferometer based on the principle of amplitude-splitting two-beam interference.

[0055] In this embodiment, the centers of the X-ray plane mirror 201 under test and the reference plane mirror 303 are located at the same horizontal height.

[0056] In this embodiment, the field of view of the X-ray plane mirror 201 under test is located at the center of the circular field of view of the plane lens 103 of the interferometer 102, ensuring that it has only a very small deviation.

[0057] In this embodiment, the reference plane mirror 303 is an X-ray plane mirror or a plane mirror lens, and the lateral dimension of the reference plane mirror 303 is not shorter than the lens diameter of the plane lens 103 of the interferometer 102. The plane lens 103 of the interferometer 102 and the reference plane mirror 303 can be other products of the same specifications for the experiment, ensuring that the X-ray plane mirror 201 under test remains unchanged during the experiment.

[0058] like Figure 2 As shown, this embodiment also provides an application method for the aforementioned X-ray plane mirror surface shape second-order absolute detection device, including the following steps:

[0059] S001: Attach a non-reflective light-blocking sheet to the reference plane mirror 303 as a marker point;

[0060] S002: Place the reference plane mirror 303 on the reference mirror mounting stage 302, and use the interferometer 102 to measure the surface shape of the reference plane mirror 303, such as... Figure 3 As shown, where R The planar lens 103 represents the interferometer 102. M The reference plane mirror 303 is represented by the black triangle and the pentagram, which represent two different beams of light.

[0061] S003: Place the X-ray plane mirror 201 to be tested on the test mirror mounting stage 202, adjust the angles of the test mirror mounting stage 202 and the reference mirror mounting stage 302, align with the marked points, and measure the full aperture surface shape of the X-ray plane mirror 201 compressed along the meridional direction, such as... Figure 4 As shown, where R The planar lens 103 represents the interferometer 102. L This indicates that the X-ray plane mirror being tested is 201. M The reference plane mirror 303 is represented by the black triangle and the pentagram, which represent two different beams of light.

[0062] S004: Calculate the second-order absolute surface shape of the X-ray plane mirror 201 under test based on the surface shape of the reference plane mirror 303 and the full aperture surface shape of the X-ray plane mirror 201 under test compressed along the meridional direction.

[0063] In step S001 of this embodiment, when a non-reflective light-blocking sheet is attached to the reference plane reflector 303 as a marker point, the light-blocking sheet can be made of paper or other light-blocking materials as needed. It can be used to align the data of the two surface shape measurements, and the surface shape measurement results are characterized by null values ​​NaN as invalid data.

[0064] In this embodiment, step S002, measuring the surface shape of the reference plane mirror 303 using the interferometer 102, includes:

[0065] S101: Adjust the angle of the reference mirror mounting stage 302 so that the fringes of the reference plane mirror 303 in the interferometer 102 are adjusted to the zero-fringe state;

[0066] S102: Use interferometer 102 to continuously measure reference plane mirror 303 and collect multiple sets of surface shape data of reference plane mirror 303;

[0067] S103: Among the multiple sets of surface shape data for the reference plane mirror 303, the result with the best continuous measurement repeatability is selected as the final surface shape of the reference plane mirror 303. For example, in this embodiment, the final surface shape of the reference plane mirror 303 is as follows: Figure 6 As shown.

[0068] In this embodiment, step S003, aligning and measuring the full aperture surface shape of the X-ray plane mirror 201 compressed along the meridional direction according to the marked points, includes:

[0069] S201: Rotate the stage 202 of the mirror under test so that the parallel beam of the interferometer 102 completely covers the X-ray plane mirror 201 under test;

[0070] S202: Rotate the reference mirror mounting stage 302 to make the returned light spot appear in the light spot diagram of the interferometer measurement software;

[0071] S203: Adjust the angle of the reference mirror stage 302, adjust the returned light spot to the center position of the CCD of the interferometer 102, and adjust the fringes to the zero-fringe state;

[0072] S204: Translate the position of the reference mirror mounting stage 302 so that the marker point appears in the area to be measured, and make the centroid of the marker point consistent with the ordinate of the centroid of the marker point in the surface shape of the reference plane mirror 303;

[0073] S205: Jump to step S203 until the condition that the zero stripe and the vertical coordinate of the marker point are consistent is met simultaneously.

[0074] S206: Use interferometer 102 to perform continuous measurements and collect multiple sets of surface shape data of the X-ray plane mirror 201 under test;

[0075] S207: Among multiple sets of surface shape data for the X-ray plane mirror 201 under test, the result with the best continuous measurement repeatability is selected as the full aperture surface shape of the X-ray plane mirror 201 under test compressed along the meridional direction. For example, in this embodiment, the final full aperture surface shape of the X-ray plane mirror 201 under test is as follows: Figure 7 As shown.

[0076] like Figure 5 As shown, in this embodiment, when aligning and measuring the full aperture surface shape of the X-ray plane mirror 201 compressed along the meridional direction according to the marker point, the step of aligning according to the marker point includes: obtaining the coordinates of the centroid of the marker point in the first measurement result (referencing the surface shape of the plane mirror 303). ; Measure the surface shape, i.e.: measure the full aperture surface shape of the X-ray plane mirror 201 under test compressed along the meridional direction; determine the coordinates of the centroid of the marker point in the second measurement result (the full aperture surface shape of the X-ray plane mirror 201 under test); Determine the coordinates of the centroid. and If the difference between the ordinates is within one pixel, then a translation adjustment is performed to change the coordinates of the centroid of the marker point when measuring the X-ray plane mirror 201. If the measurement continues, the alignment is considered complete; otherwise, the alignment is considered complete. In this embodiment, the calculation of the centroid coordinates of the marker point includes:

[0077] S301: Use a rectangle to cut out the data of the marked point area, so that only the marked point area has null value NaN data in the cut-out area, set the null value NaN data in the area to 1, and set the other non-numeric NaN data to 0.

[0078] S302: Collect all satisfied... Point location , denoted as set ,in It represents the total number of points set to 1. Point position Data, For any number k A point set to 1;

[0079] S303: Set Calculate the centroid coordinates using the following formula:

[0080] , ;

[0081] in, , These are the x and y coordinates of the centroid of the marker point, respectively, in units of a single pixel.

[0082] In step S004 of this embodiment, the calculation of the second-order absolute surface shape of the X-ray plane mirror 201 under test includes:

[0083] S401: Point-to-point subtraction is performed between the surface shape of the reference plane mirror 303 and the full-aperture surface shape of the X-ray plane mirror 201 under test, which is compressed along the meridional direction, to obtain the subtracted surface height result matrix. ;

[0084] S402: Based on the projected pixel size and the actual surface size, obtain the relative angle between the X-ray mirror under test and the interferometer beam. Calculate the difference between these relative angles to obtain the surface height matrix. The surface error matrix is ​​obtained by scaling up the model. ;

[0085] S403: Based on the actual physical dimensions of the X-ray plane mirror under test and the pixel dimensions obtained from the interferometer measurement results, calculate the scaling factors for the horizontal and vertical coordinates. Then, scale the horizontal dimensions of the horizontal and vertical coordinate matrices in the interferometer measurement results to obtain the scaled horizontal coordinate matrix. and ordinate matrix ;

[0086] S404: Magnified surface error matrix extracted along the meridian of the X-ray reflecting mirror under test. Combined with the scaled x-coordinate matrix Obtain the center intercept And using a quadratic polynomial Fitting center cutoff ;

[0087] S405: Based on the quadratic polynomial The second-order radius of curvature of the X-ray plane mirror 201 under test was obtained. The absolute surface shape of the second-order term of the X-ray plane mirror 201 under test is taken.

[0088] In step S401 of this embodiment, the relative angle between the X-ray mirror under test and the interferometer beam is obtained based on the surface projection pixel size and the actual surface size. The surface height result matrix is ​​then calculated based on this relative angle. The surface error matrix is ​​obtained by scaling up the model. At that time, including the height matrix based on the two measurements. With coordinate matrix and The surface height data from the two measurements were normalized into two large matrices of the same size. and In this approach, uncovered blank spaces within a matrix are filled with NaN (Not a Number). Then, the point-to-point difference between two matrices of the same size can be represented as:

[0089] ;

[0090] in, This is the matrix of surface shape results obtained in step S003. This is the matrix of surface shape results obtained in step S002. The resulting matrix after point-to-point subtraction can be obtained as follows: Figure 8 The surface shape shown is plotted as a point-to-point difference diagram.

[0091] In step S402 of this embodiment, the surface height result matrix after point-to-point subtraction is... The process involves scaling up the image, including: obtaining the relative angle between the X-ray mirror under test and the interferometer beam based on the pixel size of the surface projection and the actual surface size; and then calculating the surface height matrix based on the relative angle. The function expression for scaling up is:

[0092] ;

[0093] ;

[0094] ;

[0095] in, The processed surface shape result matrix, The surface shape result matrix after point-to-point subtraction as described in step S301. This is the scaling factor. The angle between the normal of the X-ray mirror being measured and the interferometer beam in step S003 is given. The projected pixel length of the X-ray mirror under test. The actual physical length of the X-ray mirror being measured. The size of a single pixel in the interferometer CCD (unit: mm / pixel).

[0096] In step S403 of this embodiment, the scaling factors of the horizontal and vertical coordinates are calculated based on the actual physical dimensions of the X-ray plane mirror under test and the pixel dimensions obtained from the interferometer measurement results. The horizontal dimensions of the horizontal and vertical coordinate matrices in the interferometer measurement results are then scaled to obtain the scaled horizontal coordinate matrix. and ordinate matrix The process involves calculating the scaling factors for the horizontal and vertical coordinates based on the actual physical dimensions of the X-ray plane mirror under test and the pixel dimensions obtained from the interferometer measurements, and then scaling the horizontal and vertical coordinate matrices accordingly.

[0097] ;

[0098] ;

[0099] ;

[0100] in, and These are the CCD horizontal and vertical coordinate matrices (unit: pixels) of the surface height matrix in step S302. and These are the horizontal and vertical coordinate matrices for the physical dimensions (unit: mm). and These are the scaling factors for the horizontal and vertical axes, respectively. and The actual physical length and width (unit: mm) of the X-ray reflector being tested are shown respectively. and These are the CCD length and width (unit: pixel) of the surface height matrix in step S302.

[0101] like Figure 9 As shown, in step S404 of this embodiment, a quadratic polynomial is used. Fitting center cutoff At time, step quadratic polynomial The function expression is:

[0102] ;

[0103] in, They are quadratic polynomials The coefficients of the quadratic term, the linear term, and the constant term are given, and a quadratic polynomial is used. Fitting center cutoff The objective is to fit a second-order polynomial. Intercepting the center line Overall deviation sum of squares Minimize the sum of squared overall deviations The function expression is:

[0104] ;

[0105] in, It is the sum of squared residuals, which is a measure of goodness of fit.

[0106] In this embodiment, the second-order radius of curvature of the X-ray plane mirror 201 under test is... The expression for the computation function is: ,in For a quadratic polynomial The coefficient of the quadratic term.

[0107] In summary, the application method of the second-order absolute detection device for X-ray plane mirror surface shape in this embodiment has been experimentally tested to measure the second-order absolute surface shape of X-ray plane mirrors, solving the problems of poor flexibility and insufficient accuracy in traditional measurement methods. The application method of the second-order absolute detection device for X-ray plane mirror surface shape in this embodiment can improve the accuracy and flexibility of the absolute measurement of the second-order surface shape of X-ray plane mirrors, and is particularly suitable for the surface shape measurement and manufacturing of X-ray plane mirrors. Compared with traditional methods, the application method of the second-order absolute detection device for X-ray plane mirror surface shape in this embodiment not only avoids the cumbersome operation of multiple measurements using the three-plate method, but also achieves high-precision alignment through pixel-level marker point feature extraction, providing more accurate measurement results, and has significant theoretical value and application prospects.

[0108] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An application method for a second-order absolute detection device for the surface shape of an X-ray plane mirror, characterized in that, The X-ray plane mirror surface shape second-order absolute detection device includes a clamping platform (101), on which an interferometer (102) and a rotating stage (203) are mounted in a fixed position. The rotating stage (203) is equipped with a test mirror clamping platform (202) that can rotate around the rotation axis of the rotating stage (203) and a reference mirror clamping connecting plate (301). The test mirror clamping platform (202) is arranged in front of the plane lens (103) of the interferometer (102). The X-ray plane mirror (201) under test is fixed in place. A reference mirror mounting stage (302) is provided on the reference mirror mounting connecting plate (301), and a reference plane mirror (303) is mounted on the reference mirror mounting stage (302). The reference plane mirror (303) is used to reflect the light reflected from the X-ray plane mirror (201) under test back to the interferometer (102) as the reference mirror mounting stage (302) rotates with the reference mirror mounting connecting plate (301). A surface lens (103) is used to measure the surface shape of the X-ray plane mirror (201) under test; the application method includes the following steps: S001: attach a non-reflective light-blocking plate as a marker on the reference plane mirror (303); S002: place the reference plane mirror (303) on the reference mirror mounting stage (302) and measure the surface shape of the reference plane mirror (303) using an interferometer (102); S003: place the X-ray plane mirror (201) under test... Place it on the test mirror mounting stage (202), adjust the angle of the test mirror mounting stage (202) and the reference mirror mounting stage (302), align with the marked point and measure the full aperture surface shape of the test X-ray plane mirror (201) compressed along the meridional direction; S004: Calculate the second-order absolute surface shape of the test X-ray plane mirror (201) based on the surface shape of the reference plane mirror (303) and the full aperture surface shape of the test X-ray plane mirror (201) compressed along the meridional direction.

2. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 1, characterized in that, The centers of the X-ray plane mirror under test (201) and the reference plane mirror (303) are located at the same horizontal height.

3. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 1, characterized in that, The field of view of the X-ray plane mirror (201) under test is located at the center of the circular field of view of the plane lens (103) of the interferometer (102).

4. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 1, characterized in that, The reference plane mirror (303) is an X-ray plane mirror or a plane mirror lens, and the lateral dimension of the reference plane mirror (303) is not shorter than the lens diameter of the plane lens (103) of the interferometer (102).

5. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 1, characterized in that, Step S002, measuring the surface shape of the reference plane mirror (303) using an interferometer (102), includes: S101: Adjust the angle of the reference mirror mounting stage (302) so that the fringes of the reference plane mirror (303) in the interferometer (102) are adjusted to the zero-fringe state; S102: Use an interferometer (102) to continuously measure the reference plane mirror (303) and collect multiple sets of surface shape data of the reference plane mirror (303); S103: Among the multiple sets of surface shape data of the reference plane mirror (303), the result with the best continuous measurement repeatability is selected as the final surface shape of the reference plane mirror (303).

6. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 1, characterized in that, Step S003, which involves aligning and measuring the full aperture surface shape of the X-ray plane mirror (201) compressed along the meridional direction according to the marked points, includes: S201: Rotate the stage (202) of the mirror under test so that the parallel beam of the interferometer (102) completely covers the X-ray plane mirror (201) under test. S202: Rotate the reference mirror mounting stage (302) to make the returned light spot appear in the spot diagram of the interferometer measurement software; S203: Adjust the angle of the reference mirror mounting stage (302), adjust the returned light spot to the center position of the CCD of the interferometer (102), and adjust the fringes to the zero-fringe state; S204: Translate the position of the reference mirror mounting stage (302) so that the marker point appears in the area to be measured, and make the centroid of the marker point consistent with the longitudinal coordinate of the centroid of the marker point in the surface shape of the reference plane mirror (303); S205: Jump to step S203 until the condition that the zero stripe and the vertical coordinate of the marker point are consistent is met simultaneously. S206: Use an interferometer (102) to perform continuous measurements and collect multiple sets of surface shape data of the X-ray plane mirror (201) under test; S207: Among the multiple sets of surface shape data of the X-ray plane mirror (201) under test, the result with the best continuous measurement repeatability is selected as the full aperture surface shape of the X-ray plane mirror (201) under test compressed along the meridional direction.

7. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 6, characterized in that, The calculation of the coordinates of the centroid of the marker point includes: S301: Use a rectangle to cut out the data of the marked point area, so that only the marked point area has null value NaN data in the cut-out area, set the null value NaN data in the area to 1, and set the other non-numeric NaN data to 0. S302: Collect all satisfied... Point location , denoted as set ,in It represents the total number of points set to 1. Point position Data, For any number k A point set to 1; S303: Set Calculate the centroid coordinates using the following formula: ， ； in, , These are the x and y coordinates of the centroid of the marker point, respectively, in units of a single pixel.

8. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 1, characterized in that, Step S004 involves calculating the second-order absolute surface shape of the X-ray plane mirror (201) under test, including: S401: Perform point-to-point subtraction between the surface shape of the reference plane mirror (303) and the full-aperture surface shape of the X-ray plane mirror (201) compressed along the meridional direction to obtain the subtracted surface shape height result matrix. ; S402: Based on the projected pixel size and the actual surface size, obtain the relative angle between the X-ray mirror under test and the interferometer beam. Calculate the difference between these relative angles to obtain the surface height matrix. The surface error matrix is ​​obtained by scaling up the model. ; S403: Based on the actual physical dimensions of the X-ray plane mirror (201) under test and the pixel dimensions obtained from the interferometer measurement results, calculate the scaling factors for the horizontal and vertical coordinates. Then, scale the horizontal dimensions of the horizontal and vertical coordinate matrices in the interferometer measurement results to obtain the scaled horizontal coordinate matrix. and ordinate matrix ; S404: Magnified surface error matrix extracted along the meridian of the X-ray reflecting mirror under test. Combined with the scaled x-coordinate matrix Obtain the center intercept And using a quadratic polynomial Fitting center cutoff ; S405: Based on the quadratic polynomial The second-order radius of curvature of the X-ray plane mirror (201) under test is obtained. The absolute surface shape of the second-order term of the X-ray plane mirror (201) under test is used.

9. The application method of the second-order absolute detection device for the surface shape of an X-ray plane mirror according to claim 8, characterized in that, The quadratic polynomial in step S404 The function expression is: ； in, They are quadratic polynomials The coefficients of the quadratic term, the linear term, and the constant term are given, and a quadratic polynomial is used. Fitting center cutoff The objective is to fit a second-order polynomial. Intercepting the center line Overall deviation sum of squares Minimize; the second-order radius of curvature of the X-ray plane mirror (201) under test. The expression for the computation function is: ,in For a quadratic polynomial The coefficient of the quadratic term.

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