A method and apparatus for measuring a neutron optical collimator

Abstract

The application provides a neutron optical collimator measurement method and device, which uses a laser beam to penetrate a diaphragm and form an image on a receiving plate, indirectly calculates the angle by analyzing the projection geometry, overcomes the physical limitations of direct contact measurement, avoids the deformation or damage risk of the flexible diaphragm caused by the contact measurement, and meets the requirements of the precision characteristics. The laser beam can explore the narrow space inside the collimator, measure the diaphragm parameters with small angles / small intervals, and is not disturbed by the characteristics of the flexible material itself, and the measurement result is more stable and reliable. By using an accurate laser beam and a known distance from the laser to the receiving plate, combined with projection image analysis, the angle measurement can be converted into an image processing and geometric calculation problem, and high precision can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of neutron optical collimator, in particular to a neutron optical collimator measurement method and device. BACKGROUND

[0002] The neutron optical collimator is a key optical component in the neutron scattering spectrometer, which is mainly used to constrain the direction of the neutron beam, control the divergence, improve the resolution, and define the standard volume of neutron diffraction. The neutron collimator filters out the neutron beam with approximately parallel direction through the slit channel formed by the absorbing material, and shields the divergent or scattered neutrons to ensure the collimation of the neutron beam. The slit extension line of the radial collimator converges at a point (focal point), so that the neutron beam can only pass through at a specific angle. The neutron collimator includes fan-shaped thin sheets, which are referred to as diaphragms hereinafter.

[0003] The small angle / small interval between the diaphragms of the neutron optical fine collimator, the narrow space (narrow field of view), and the high precision (1 / 1000 degree or micrometer level) of the flexible diaphragm pose significant challenges to the measurement. Since the diaphragm is made of flexible material and has precise characteristics, the contact measurement method cannot be used to directly obtain the angle information between the diaphragms. Therefore, an indirect measurement method is needed to obtain the relevant characteristic parameters, and then the angle value is calculated. However, the traditional scanning measurement method is easily disturbed by the material characteristics and the on-site environmental factors, and it is difficult to completely obtain the information on the surface of the measured object, resulting in low measurement efficiency and large measurement error. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a neutron optical collimator measurement method and device to solve the problem of low measurement efficiency and large measurement error of the existing measurement scheme for the neutron optical collimator.

[0005] The neutron optical collimator measurement method provided by the embodiments of the present application is characterized in that a measured collimator is arranged on a rotary table, a first laser is located on the central axis of the rotary table, and the first laser is located inside the measured collimator. A receiving plate is arranged outside the measured collimator.

[0006] The method comprises the following steps.

[0007] When the rotary table is at an initial rotation angle and an initial height, the laser beam emitted by the first laser irradiates the inside of the measured collimator and reaches the receiving plate after passing through the diaphragm of the measured collimator.

[0008] A projection image of the receiving plate plane is obtained, and a diaphragm projection geometric relationship is obtained according to the distance between the first laser and the receiving plate.

[0009] According to the diaphragm projection geometric relationship, the diaphragm included angle between two adjacent diaphragms of the measured collimator is obtained.

[0010] In the technical solution, the laser beam penetrates the membrane and forms an image on the receiving plate, and the angle is indirectly calculated by analyzing the projection geometry, which overcomes the physical limitations of direct contact measurement, avoids the deformation or damage risk of the flexible membrane caused by contact measurement, and meets the requirements of the precision characteristics. The laser beam can explore the narrow space inside the collimator, measure the membrane parameters with small angle / small interval, and is not disturbed by the characteristics of the flexible material itself, so the measurement result is more stable and reliable. By using the accurate laser beam and the known distance from the laser to the receiving plate, combined with the projection image analysis, the angle measurement can be converted into image processing and geometric calculation, which can achieve high precision.

[0011] In some optional embodiments, the membrane included angle between two adjacent membranes of the collimator to be measured is obtained according to the projection geometry of the membranes, comprising:

[0012] If the projection width of the central membrane in the projection image is less than a set threshold, the central membrane is parallel to the laser beam, and at this time, the included angle is obtained by using one-side recognition;

[0013] If the projection width of the central membrane in the projection image is greater than or equal to a set threshold, the central membrane is not parallel to the laser beam, and at this time, the included angle is obtained by using two-side recognition.

[0014] In the technical solution, the projection width of the central membrane is used to determine the parallel state of the membrane, and the optimal algorithm is automatically selected. When the central membrane is parallel to the laser beam, the projection width is small (less than a set threshold), and one-side recognition is used. One-side recognition usually only needs to analyze the edge information of one side of the projection image, and the algorithm complexity is significantly lower than that of two-side recognition. When the central membrane is not parallel to the laser beam, the projection width is greater than or equal to a set threshold, and two-side recognition mode accurately captures the offset caused by the inclination by simultaneously analyzing the edges of both sides, thereby ensuring the accuracy of the calculation under the inclined state.

[0015] The judgment method of the central membrane of the projection image is that the width information of each membrane in the projection image is extracted, and a membrane width curve is drawn according to the width information of each membrane, and the membrane with the smallest width in the membrane width curve is found out, and the membrane with the smallest width is taken as the central membrane.

[0016] In some optional embodiments, the included angle is obtained by using one-side recognition, comprising:

[0017] According to the length of the central membrane along the beam direction and the interval difference of the adjacent membranes in the inner and outer sectors, the included angle of the membrane is obtained:

[0018] ;

[0019] wherein L is the length of the central membrane along the beam direction, and D is the interval difference of the adjacent membranes in the inner sector and the outer sector; ; is the inner sector distance of the adjacent membranes, is the outer sector distance of the adjacent membranes. The adjacent membranes are the adjacent membranes on both sides of the central membrane.

[0020] In the above technical solution, in an ideal case, i.e., when the laser beam is parallel to the central membrane, the membrane angle can be measured and accurately obtained through single-side recognition. A membrane group is formed by a certain membrane and the two adjacent membranes on the left and right sides. The length of the central membrane along the beam direction is , the interval difference of the adjacent membranes in the inner sector and the outer sector is , the membrane angle between the central membrane and the adjacent membrane is ; the inner sector membrane distance and the outer sector membrane distance are obtained through the projection image, wherein the interval difference between the inner sector and the outer sector is .

[0021] In some optional embodiments, the membrane angle is obtained by using a double-side recognition method, which includes:

[0022] According to the interval difference of the adjacent membranes in the inner sector and the outer sector and the radial effective length of the neutron absorption coating of the adjacent membranes, the membrane angle is obtained:

[0023] ;

[0024] wherein is the radial effective length of the neutron absorption coating of the central membrane, is the radial effective length of the neutron absorption coating of the adjacent membranes, and D is the interval difference of the adjacent membranes in the inner sector and the outer sector; ; is the outer sector distance of the two-side membranes, is the inner sector distance of the two-side membranes; the total thickness value of the membrane is ; the membrane substrate thickness is , and the double-sided neutron absorption coating thickness value is .

[0025] In the above technical solution, the double-side recognition method is based on the projection of the central membrane and the left and right membranes to solve the membrane angle between the central membrane and one adjacent membrane. The length of the central membrane along the beam direction is , the interval difference of the central membrane and one adjacent membrane in the inner sector and the outer sector is , the radial effective length of the neutron absorption coating of the central membrane is , and the radial effective length of the neutron absorption coating of the adjacent membrane is the membrane base thickness of the adjacent membrane is the adjacent membrane double-sided neutron absorbing coating thickness value is then the total thickness value of the membrane is the adjacent membrane inner and outer side projection image pixel values are the camera calibration value is the outer fan-shaped distance of the two sides of the central membrane is the inner fan-shaped distance of the two sides of the central membrane is then the interval difference of the adjacent membranes in the inner and outer fan-shaped is that is, the membrane included angle can be calculated as:

[0026] .

[0027] In some optional embodiments, the to-be-measured collimator rotates with the turntable, and the first laser does not rotate with the turntable.

[0028] After obtaining the membrane included angle between two adjacent membranes of the to-be-measured collimator according to the membrane projection geometric relationship, the method further includes:

[0029] The turntable rotates by a set angle, measures the next membrane included angle, and repeats the process until the membrane included angles between all adjacent membranes are measured.

[0030] The set angle is usually the included angle value between adjacent membranes of a standard collimator.

[0031] In the above technical solution, by rotating the turntable, the precision single-point measurement is upgraded to full-automatic high-precision collimator performance analysis, which greatly improves the detection efficiency, reduces the labor cost and the requirement for the environment, and provides indispensable comprehensive data support for guaranteeing the final performance of the neutron optical collimator and performing strict quality control.

[0032] In some optional embodiments, after measuring the membrane included angles between all adjacent membranes, the method further includes:

[0033] According to the membrane included angles between all adjacent membranes at the initial height, an angle correction value is obtained.

[0034] In the above technical solution, multiple measurement images are captured during the rotation of the optical turntable, and a function model is established to describe the relationship between the observed value and the theoretical value based on the observation of the included angles of the adjacent membrane groups during the rotation of the optical turntable:

[0035] According to the equivalent relationship between the adjacent angle adjustment value and the correction number, and the theoretical observed value and the observation error, a calculation model is built as:

[0036] ;

[0037] wherein, is the number of diaphragm images, is the angle adjustment value, is the angle correction number, is the theoretical observation value, is the observation error, and n is the total number of diaphragms.

[0038] Based on the least square adjustment method, the difference between the observation value and the theoretical value is constructed, and the error equation is constructed according to the relationship between the observation error and the to-be-solved parameter (the angle correction number):

[0039] According to the observation error , the to-be-solved parameter is , is the coefficient matrix in the error equation, is the constant term, and the error equation is: ;

[0040] Considering the geometric characteristics of angle closure, an additional constraint condition is introduced: since the angle has closure (the sum is ), the condition of the angle sum is converted into a matrix form, that is, ;

[0041] The to-be-solved parameter , is the coefficient matrix (the elements are order vectors), is the constant term related to the angle sum, and it is arranged as: ;

[0042] The error equation and the additional constraint condition are combined into a comprehensive error equation:

[0043] ;

[0044] wherein is the submatrix of the coefficient matrix of the equation, is a matrix in the adjustment calculation process, which is used to process the additional constraint condition, so as to accurately solve the unknown parameter under the conditions of meeting the relationship between the observation value and the position parameter (the error equation) and the additional constraint condition. The conditional indirect adjustment method is adopted, the least square principle is used, the square sum of the observation error is minimized under the conditions of meeting the error equation and the additional constraint condition, and the value of the to-be-solved parameter (the angle correction number) is obtained: , so as to finally determine the angle adjustment value .

[0045] In some optional embodiments, the turntable can move up and down along the center axis of the turntable.

[0046] The angle correction value is obtained according to the dihedral angle between all adjacent diaphragms at the initial height.

[0047] The height of the rotary table is adjusted, the dihedral angle between all adjacent diaphragms at different height positions of the to-be-measured collimator is measured, and the angle correction value is calculated; the process is repeated until the dihedral angle between all adjacent diaphragms at all preset height positions of the to-be-measured collimator is measured.

[0048] In the technical solution, the Z-axis scanning is used to realize the angle measurement of the collimator in the full height space.

[0049] The embodiment of the present application provides a neutron optical collimator measuring device, which comprises a rotary table, a first laser, a receiving plate and a controller; the rotary table can rotate around a rotary table center axis, and the rotary table can also move up and down along the rotary table center axis; a to-be-measured collimator is arranged on the rotary table, the first laser is located on the rotary table center axis, and the first laser is located on the inside of the to-be-measured collimator; the receiving plate is arranged on the outside of the to-be-measured collimator; the controller is connected with the receiving plate, the first laser and the rotary table.

[0050] The controller is used for executing the neutron optical collimator measuring method.

[0051] In some optional embodiments, the second laser and the third laser are further included.

[0052] The second laser and the third laser are respectively installed on two sides of the bottom of the to-be-measured collimator; and the second laser and the third laser are used for positioning the installation position of the to-be-measured collimator on the rotary table.

[0053] In some optional embodiments, the receiving plate comprises a telecentric mirror and a CCD camera; and the first laser comprises a double-telecentric mirror laser. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0055] Figure 1 The neutron optical collimator measuring schematic diagram provided by the embodiments of the present application;

[0056] Figure 2 The neutron optical collimator measuring method step flowchart provided by the embodiments of the present application;

[0057] Figure 3 A neutron optical collimator measurement workflow diagram provided by the embodiment of the present application is shown in FIG. 1.

[0058] Figure 4 A schematic diagram of installation of the second laser and the third laser is shown in FIG. 2.

[0059] Figure 5 A schematic diagram of membrane projection geometry when the central membrane is parallel to the laser beam is shown in FIG. 3.

[0060] Figure 6 A schematic diagram of membrane projection geometry when the central membrane is not parallel to the laser beam is shown in FIG. 4. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0062] Please refer to Figure 1 , Figure 1 A schematic diagram of neutron optical collimator measurement provided by the embodiment of the present application is shown in FIG. 1. The collimator to be measured is arranged on a rotary table, the first laser is located on the central axis of the rotary table, and the first laser is located inside the collimator to be measured. A receiving plate is arranged outside the collimator to be measured.

[0063] Please refer to Figure 2 , Figure 2 A neutron optical collimator measurement method step flow chart provided by the embodiment of the present application is shown in FIG. 2. The measurement method comprises the following steps.

[0064] Step S1, when the rotary table is at an initial rotation angle and an initial height, the laser beam emitted by the first laser irradiates the inside of the collimator to be measured, and reaches the receiving plate after passing through the membrane of the collimator to be measured.

[0065] Step S2, the projection image of the receiving plate plane is obtained, and the membrane projection geometry is obtained according to the distance between the first laser and the receiving plate.

[0066] The receiving plate comprises a CCD camera, which can obtain the projection image of the laser beam emitted by the first laser and projected onto the receiving plate plane after passing through the collimator to be measured. The projection image comprises a projection shadow area of the membrane of the neutron optical collimator, so as to obtain the projection width of the membrane. According to the projection width of the membrane and the distance between the first laser and the receiving plate, the membrane projection geometry in the horizontal plane can be obtained, for example, as shown in Figure 5 、 Figure 6 .

[0067] Step S3, according to the membrane projection geometry, the membrane included angle between two adjacent membranes of the collimator to be measured is obtained.

[0068] In the embodiments of the present application, the laser beam penetrates the film and forms an image on the receiving plate, and the angle is indirectly calculated by analyzing the projection geometry, which overcomes the physical limitations of direct contact measurement, avoids the deformation or damage risk of the flexible film caused by contact measurement, and meets the requirements of its precision characteristics. The laser beam can explore the narrow space inside the collimator, measure the film parameters with small angles / small intervals, and is not disturbed by the characteristics of the flexible material itself, so the measurement result is more stable and reliable. By using an accurate laser beam and a known distance from the laser to the receiving plate, combined with projection image analysis, the angle measurement can be converted into an image processing and geometric calculation problem, which can achieve high precision. Specifically, when measuring the angle, the film angle between the central film and the adjacent film is measured, and the central film is the film with the smallest projection width in the projection image; if the central film is parallel to the laser beam, the film angle between the central film and the adjacent film can be obtained by single-side recognition combined with the geometric relationship of an adjacent film; if the central film is not parallel to the laser beam, the film angle between the central film and the adjacent film can be obtained by double-side recognition combined with the geometric relationship of two adjacent films.

[0069] Please refer to Figure 3 , Figure 3 The neutron optical collimator measurement workflow diagram provided in the embodiments of the present application is shown in FIG. 1.

[0070] In some optional embodiments, according to the film projection geometry, the film angle between two adjacent films of the collimator to be measured is obtained, including:

[0071] If the projection width of the central film in the projection image is less than a set threshold, the central film is parallel to the laser beam, and at this time, the film angle is obtained by using single-side recognition;

[0072] If the projection width of the central film in the projection image is greater than or equal to the set threshold, the central film is not parallel to the laser beam, and at this time, the film angle is obtained by using double-side recognition.

[0073] In the embodiments of the present application, the projection width of the central film is used to determine the parallel state of the film, and the optimal algorithm is automatically selected. When the central film is parallel to the laser beam, the projection width is small (less than a set threshold), and single-side recognition is used. Single-side recognition usually only needs to analyze the edge information on one side of the projection image, and the algorithm complexity is significantly lower than that of double-side recognition. When the central film is not parallel to the laser beam, the projection width is greater than or equal to the set threshold, and double-side recognition mode simultaneously analyzes the edges on both sides to accurately capture the offset caused by the inclination, thereby ensuring the accuracy of the calculation under the inclined state.

[0074] The judging method of the central membrane piece of the projection image is: extracting the width information of each membrane piece in the projection image, drawing a membrane piece width curve according to the width information of each membrane piece, finding out the membrane piece with the minimum width in the membrane piece width curve, and taking the membrane piece with the minimum width as the central membrane piece.

[0075] Please refer to Figure 5 , Figure 5 The membrane piece projection geometric relation schematic diagram when the central membrane piece is parallel to the laser beam is provided for the embodiments of the present application.

[0076] In some optional embodiments, the membrane piece included angle is obtained by using one-side identification, including:

[0077] According to the length of the central membrane piece along the beam direction and the interval difference of the adjacent membrane pieces in the inner fan and the outer fan, the membrane piece included angle is obtained:

[0078] ;

[0079] Wherein, L is the length of the central membrane piece along the beam direction, and D is the interval difference of the adjacent membrane pieces in the inner fan and the outer fan. ; The inner fan distance of the adjacent membrane pieces is The outer fan distance of the adjacent membrane pieces is. The adjacent membrane pieces are the membrane pieces adjacent to the central membrane piece on both sides.

[0080] In the embodiments of the present application, in the ideal case, that is, when the laser beam is parallel to the central membrane piece, the membrane piece included angle can be measured and accurately obtained by one-side identification. A certain membrane piece and the two adjacent membrane pieces on the left and right form a membrane piece group. The length of the central membrane piece along the beam direction is , the interval difference of the adjacent membrane pieces in the inner fan and the outer fan is , and the membrane piece included angle between the central membrane piece and the adjacent membrane pieces is The inner fan membrane piece distance is obtained from the projection image , the outer fan membrane piece distance is , and the interval difference between the inner and outer is .

[0081] Please refer to Figure 6 , Figure 6 The membrane piece projection geometric relation schematic diagram when the central membrane piece is not parallel to the laser beam is provided for the embodiments of the present application.

[0082] In some optional embodiments, the membrane piece included angle is obtained by using two-side identification, including:

[0083] According to the interval difference of the adjacent membrane pieces in the inner fan and the outer fan and the radial effective length of the adjacent membrane pieces, the membrane piece included angle is obtained:

[0084] ;

[0085] wherein, is the radial effective length of the neutron absorption coating in the central membrane, is the radial effective length of the neutron absorption coating in the adjacent membrane, and D is the interval difference between the inner sector and the outer sector of the adjacent membrane; ; is the outer sector distance of the two side membranes, is the inner sector distance of the two side membranes; the total thickness value of the membrane is ; the membrane base thickness is , and the double-sided neutron absorption coating thickness value is .

[0086] In the embodiments of the present application, the bilateral recognition mode is to solve the membrane angle of the central membrane and one adjacent membrane based on the projection of the central membrane and the left and right membranes. The length of the central membrane along the beam direction is , the interval difference between the inner sector and the outer sector of the central membrane and one adjacent membrane is , the radial effective length of the neutron absorption coating in the central membrane is , the radial effective length of the neutron absorption coating in the adjacent membrane is , the membrane base thickness of the adjacent membrane is , and the double-sided neutron absorption coating thickness value of the adjacent membrane is , then the total thickness value of the membrane is , the pixel values of the inner and outer projection images of the adjacent membrane are , the camera calibration value is , the outer sector distance of the two side membranes of the central membrane is , the inner sector distance of the two side membranes is , and the interval difference between the inner and outer sectors of the adjacent membrane is , that is, the membrane angle can be calculated as:

[0087] .

[0088] In some optional embodiments, the collimator to be measured rotates with the turntable, and the first laser does not rotate with the turntable.

[0089] After obtaining the membrane angle between two adjacent membranes of the collimator to be measured according to the projection geometry of the membrane, the method further comprises:

[0090] The turntable rotates by a set angle, the next membrane angle is measured, and the process is repeated until the membrane angles between all adjacent membranes are measured.

[0091] wherein, the set angle is usually the angle value between the adjacent membranes of the standard collimator. In the standard collimator, the angle value between the adjacent membranes is 0.1°-2°, for example, 1.5°.

[0092] In the embodiments of the application, through rotation of the turntable, the precision single-point measurement is upgraded to full-automatic high-precision collimator performance analysis, which greatly improves the detection efficiency, reduces the labor cost and the requirement for the environment, and provides indispensable comprehensive data support for guaranteeing the final performance of the neutron optical collimator and performing strict quality control.

[0093] In some optional embodiments, after measuring the dihedral angle between all adjacent two diaphragms, the method further comprises:

[0094] According to the dihedral angle between all adjacent two diaphragms at the initial height, an angle correction value is obtained.

[0095] In the embodiments of the application, multiple measurement images are captured during the rotation of the optical turntable, and a function model is established to describe the relationship between the observed value and the theoretical value based on the observation of the dihedral angle of the adjacent diaphragm group during the rotation of the optical turntable:

[0096] According to the equivalent relationship between the adjacent angle adjustment value and the correction number, and the theoretical observation value and the observation error, a calculation model is built as:

[0097] ;

[0098] wherein, is the number of diaphragm images, is the angle adjustment value, is the angle correction number, is the theoretical observation value, is the observation error, and n is the total number of diaphragms.

[0099] Based on the least square adjustment method, the difference between the observed value and the theoretical value is constructed, and an error equation is constructed according to the relationship between the observation error and the to-be-solved parameter (angle correction number):

[0100] According to the observation error , the to-be-solved parameter is , is the coefficient matrix in the error equation, is a constant term, and the error equation is: ;

[0101] Considering the geometric characteristics of angle closure, an additional constraint condition is introduced: since the angle has closure (the sum is ), the condition of the total sum of the angle is converted into a matrix form, that is, ;

[0102] The to-be-solved parameter , is the coefficient matrix (the elements are all order vectors), is the constant term related to the angle sum, then it is arranged as ;

[0103] The error equation and the additional constraint conditions are combined into a comprehensive error equation:

[0104] ;

[0105] wherein is a submatrix of the coefficient matrix of the equation, is a matrix in the adjustment calculation process, used to process the additional constraint conditions, to ensure that the unknown parameters are accurately solved under the conditions of meeting the observation value and position parameter relationship (error equation) and the additional constraint conditions, using the indirect adjustment method with conditions, using the least square principle, under the conditions of meeting the error equation and the additional constraint conditions, the square sum of the observation errors is minimized, so as to obtain the value of the to-be-solved parameter (angle correction number): , so as to finally determine the angle adjustment value .

[0106] In some optional embodiments, the turntable can move up and down along the center axis of the turntable.

[0107] After obtaining the angle correction value according to the dihedral angle between all adjacent two diaphragms at the initial height, the method further includes:

[0108] Adjusting the height of the turntable, measuring the dihedral angle between all adjacent two diaphragms at different height positions of the to-be-measured collimator, and calculating the angle correction value; repeating the process until the dihedral angle between all adjacent diaphragms at all preset height positions of the to-be-measured collimator is measured.

[0109] wherein the height of the diaphragm is usually 100mm-1900mm, for example, 724mm. In this embodiment, 1% of the height of the diaphragm can be used as the adjustment step value when adjusting the height of the turntable.

[0110] In the embodiment of the application, the angle measurement of the collimator in the full height space is realized through Z-axis scanning.

[0111] The neutron optical collimator measuring device provided in the embodiment of the application includes a turntable, a first laser, a receiving plate and a controller; the turntable can rotate around the center axis of the turntable, and the turntable can also move up and down along the center axis of the turntable; the to-be-measured collimator is arranged on the turntable, the first laser is located on the center axis of the turntable, and the first laser is located inside the to-be-measured collimator; the receiving plate is arranged outside the to-be-measured collimator; the controller is connected with the receiving plate, the first laser and the turntable.

[0112] The controller is used to execute the neutron optical collimator measuring method as any one of the above.

[0113] Please refer to Figure 4 , Figure 4 is a schematic view of installation of the second laser and the third laser.

[0114] In some optional embodiments, further comprising: the second laser and the third laser;

[0115] The second laser and the third laser are respectively installed on two sides of the bottom of the collimator to be measured; the second laser and the third laser are used for positioning the installation position of the collimator to be measured on the turntable.

[0116] Specifically, the second laser and the third laser are usually installed on two sides of the bottom of the collimator to be measured, and the second laser and the third laser are respectively parallel to the two outermost diaphragms of the collimator to be measured; if the laser points irradiated by the second laser and the third laser are located in the range of the calibrated circular region, it is considered that the collimator to be measured is installed to the specified position; if the laser points irradiated by the second laser and the third laser exceed the range of the calibrated circular region, it is considered that the collimator to be measured is not installed to the specified position.

[0117] In some optional embodiments, the receiving plate comprises a telecentric lens and a CCD camera; and the first laser comprises a double-telecentric lens laser.

[0118] The telecentric lens is a special designed optical lens, the core feature of which is that the chief ray (optical axis) is parallel to the imaging plane, thereby eliminating the perspective distortion (near-large and far-small effect) caused by the change of the object distance of the traditional lens. It realizes this feature by setting a diaphragm (aperture diaphragm located on the focal plane of the lens) inside the lens. The CCD camera is a kind of image sensor camera based on charge-coupled device (CCD). The CCD converts the light signal into electric charge through photoelectric effect, and then transfers and outputs the electric charge row by row through the internal circuit as a digital signal, and finally forms an image.

[0119] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some communication interfaces, devices or units, and can be electrical, mechanical or other forms.

[0120] In addition, the units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0121] Furthermore, each functional module in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0122] In this paper, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations.

[0123] The above is only an embodiment of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for measuring neutron optical collimators, characterized in that, The to-be-measured collimator is arranged on the rotary table, the first laser is located on the central axis of the rotary table, and the first laser is located inside the to-be-measured collimator, and a receiving plate is arranged outside the to-be-measured collimator; The method comprises: When the rotary table is at an initial rotation angle and an initial height, the laser beam emitted by the first laser irradiates the inside of the to-be-measured collimator and reaches the receiving plate after passing through the diaphragm of the to-be-measured collimator; A projection image of the receiving plate plane is acquired, and a diaphragm projection geometric relationship is obtained according to the distance between the first laser and the receiving plate; According to the diaphragm projection geometric relationship, a diaphragm included angle between two adjacent diaphragms of the to-be-measured collimator is obtained. The diaphragm included angle obtained according to the diaphragm projection geometric relationship comprises: If the projection width of the central diaphragm in the projection image is less than a set threshold, the diaphragm included angle is obtained by using a single-side recognition method; If the projection width of the central diaphragm in the projection image is greater than or equal to the set threshold, the diaphragm included angle is obtained by using a double-side recognition method. The diaphragm included angle obtained by using the single-side recognition method comprises: According to the length of the central diaphragm along the beam direction and the interval difference of the adjacent diaphragms between the inner sector and the outer sector, the diaphragm included angle is obtained. ； wherein L is the length of the central diaphragm along the beam direction, and D is the difference in spacing between adjacent diaphragms at the inner and outer scallops; ; is the inner scallop distance of adjacent diaphragms, is the outer scallop distance of adjacent diaphragms; The diaphragm included angle obtained by using the double-side recognition method comprises: According to the interval difference of the adjacent diaphragms between the inner sector and the outer sector and the radial effective length of the neutron-absorbing coating of the adjacent diaphragms, the diaphragm included angle is obtained. ； wherein, Dc is the radial effective length of the neutron absorbing coating in the center tile, Dn is the radial effective length of the neutron absorbing coating in the adjacent tile, and D is the difference in spacing between the inner sector and the outer sector of the adjacent tile; ; Dout is the distance of the outer sector of the two-sided tile, Din is the distance of the inner sector of the two-sided tile; the total tile thickness value is ; the tile base thickness is , and the double-sided neutron absorbing coating thickness value is .

2. The method of claim 1, wherein, The to-be-measured collimator rotates with the rotary table, and the first laser does not rotate with the rotary table. After the diaphragm included angle between two adjacent diaphragms of the to-be-measured collimator is obtained according to the diaphragm projection geometric relationship, the method further comprises: The rotary table rotates by a set angle, the next diaphragm included angle is measured, and the process is repeated until the diaphragm included angles between all adjacent diaphragms are measured.

3. The method of claim 2, wherein, After the diaphragm included angles between all adjacent diaphragms are measured, the method further comprises: According to the diaphragm included angles between all adjacent diaphragms at the initial height, an angle correction value is obtained.

4. The method of claim 3, wherein, The rotary table can move up and down along the central axis of the rotary table. After the angle correction value is obtained according to the diaphragm included angles between all adjacent diaphragms at the initial height, the method further comprises: The height of the rotary table is adjusted, the diaphragm included angles between all adjacent diaphragms at different height positions of the to-be-measured collimator are measured, and an angle correction value is calculated; the process is repeated until the diaphragm included angles between all adjacent diaphragms at all preset height positions of the to-be-measured collimator are measured.

5. A neutron optical collimator measurement device, characterized by, The apparatus comprises a rotary table, a first laser, a receiving plate and a controller; the rotary table can rotate around the central axis of the rotary table, and the rotary table can also move up and down along the central axis of the rotary table; a to-be-measured collimator is arranged on the rotary table, the first laser is located on the central axis of the rotary table, and the first laser is located inside the to-be-measured collimator; the receiving plate is arranged outside the to-be-measured collimator; the controller is connected to the receiving plate, the first laser and the rotary table. The controller is used to execute the neutron-optical collimator measurement method according to any one of claims 1-4.

6. The apparatus of claim 5, wherein, The apparatus further comprises: The second laser and the third laser; The second laser and the third laser are respectively installed on two sides of the bottom of the collimator to be tested; The second laser and the third laser are used for positioning the installation position of the collimator to be tested on the rotary table.

7. The apparatus of claim 5, wherein, The receiving plate comprises a telecentric lens and a CCD camera; and the first laser comprises a double-telecentric lens laser.

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