A collimation device and method for a multi-slit aperture in a neutron scattering spectrometer

Abstract

The present invention discloses a collimation device and method for a multi-slit aperture in a neutron scattering spectrometer. The device includes an optical input end, an optical output end, a motion component connected to the multi-slit aperture, and a computer. The optical input end is used to output a laser beam, and the laser beam passes through one of the multi-slit apertures to the optical output end. The optical output end is used to form an image based on the laser beam. The computer is used to obtain the actual center position of the multi-slit aperture corresponding to each image according to each image, and control the movement of multiple motion components according to multiple actual center positions to adjust multiple multi-slit apertures to align with the actual center position of one of the multi-slit apertures as a reference. Thereby improving the relative position accuracy of multiple multi-slit apertures of the neutron scattering spectrometer, and further improving the measurement accuracy of the neutron scattering spectrometer.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron scattering spectrometers, and in particular, to a collimation device and method for a multi-slit aperture in a neutron scattering spectrometer. Background Art

[0002] The Very Small Angle Scattering (VSANS) spectrometer of the China Spallation Neutron Source can study materials such as polymers and biological macromolecules in the scale range of 1 - 1000 nm, and can be widely used in scientific research fields such as physics, chemistry, materials, biomedicine, polymers, environmental protection, and archaeology.

[0003] In the scattering spectrometer, 12 multi-slit apertures (Multi-slit, MS) are unevenly distributed on its 12.3-meter-long neutron beam line. Its function is to focus neutrons on the detector surface. However, the problem is that the current positions of the 12 multi-slit apertures cannot be well aligned on a straight line, which makes the measurement accuracy of the scattering spectrometer far from meeting the requirements. Summary of the Invention

[0004] The present invention provides a collimation device and method for a multi-slit aperture in a neutron scattering spectrometer to improve the relative position accuracy of multiple multi-slit apertures in the neutron scattering spectrometer, thereby improving the measurement accuracy of the neutron scattering spectrometer.

[0005] To achieve the above object, an embodiment of one aspect of the present invention provides a collimation device for a multi-slit aperture in a neutron scattering spectrometer, including: an optical input end, an optical output end, a motion component connected to the multi-slit aperture, and a computer;

[0006] The optical input end is used to output a laser beam, and the laser beam passes through one of the multi-slit apertures to the optical output end. The optical output end is used to form an image according to the laser beam;

[0007] The computer is used to obtain the actual center position of the multi-slit aperture corresponding to the image according to each image; and control the movement of the multiple motion components according to the multiple actual center positions to adjust the multiple multi-slit apertures to be aligned with the actual center position of one of the multi-slit apertures as a reference.

[0008] Optionally, the optical input end includes:

[0009] A first laser, a first aperture, a first attenuation mirror, a beam expander, and a second aperture. The first laser is used to emit the laser beam, and the laser beam sequentially passes through the first aperture, the first attenuation mirror, the beam expander, and the second aperture to the multi-slit aperture.

[0010] Optionally, the optical input end further includes:

[0011] A first optical path adjustment component and a third aperture stop. The laser beam passing through the second aperture stop passes through the first optical path adjustment component and the third aperture stop in sequence and then reaches the multi-slit aperture stop.

[0012] Optionally, the first optical path adjustment component includes:

[0013] A first reflecting mirror, a fourth aperture stop, and a second reflecting mirror. The first reflecting mirror is used to reflect the laser beam passing through the second aperture stop to the fourth aperture stop, and the second reflecting mirror is used to reflect the laser beam passing through the fourth aperture stop to the third aperture stop.

[0014] Optionally, the optical input end further includes: a semi-reflective semi-transmissive lens, a second attenuation mirror, and a position-sensitive detector;

[0015] The semi-reflective semi-transmissive lens is located between the laser and the first aperture stop, and is used to transmit a part of the laser beam emitted by the laser as a first laser beam and reflect a part as a second laser beam; the first laser beam is used to pass through the multi-slit aperture stop to the optical output end to form an image; the second laser beam passes through the second attenuation mirror to the position-sensitive detector.

[0016] Optionally, the optical input end further includes: a second optical path adjustment component, which is located on the propagation path of the second laser beam. The second laser beam passes through the second optical path adjustment component and the second attenuation mirror in sequence and then reaches the position-sensitive detector.

[0017] Optionally, the optical input end further includes: a second laser and a third optical path adjustment component;

[0018] The second laser is used to emit a laser beam to the third optical path adjustment component when the first laser fails. The laser beam is adjusted by the third optical path adjustment component and then incident on the semi-reflective semi-transmissive lens to form the first laser beam and the second laser beam.

[0019] Optionally, the optical output end includes: a fifth aperture stop, a lens, and a camera. The laser beam passing through the multi-slit aperture stop passes through the fifth aperture stop and the lens in sequence and then forms an image on the camera.

[0020] To achieve the above object, a collimation method for a multi-slit aperture stop in a neutron scattering spectrometer according to a second aspect embodiment of the present invention is implemented based on the collimation device for a multi-slit aperture stop in the neutron scattering spectrometer as described above, and includes the following steps:

[0021] Obtain an image formed by a laser beam passing through one of the multi-slit diaphragms at the optical output end;

[0022] Obtain the actual central position of the multi-slit diaphragm according to the image;

[0023] Repeat the above steps to obtain the actual central position corresponding to each multi-slit diaphragm;

[0024] Control the movement of the motion components connected to each multi-slit diaphragm to adjust the multiple multi-slit diaphragms to align with the actual central position of one of the multi-slit diaphragms as a reference.

[0025] Optionally, the obtaining the actual central position of the multi-slit diaphragm according to the image includes:

[0026] Obtain the two-dimensional gray-scale matrix of the image;

[0027] Integrate the data along the slit direction of the multi-slit diaphragm according to the two-dimensional gray-scale matrix to obtain an intensity curve;

[0028] Obtain multiple peak positions of the multi-slit diaphragm according to the intensity curve;

[0029] Obtain the central position of the multi-slit diaphragm according to the multiple peak positions.

[0030] Optionally, before obtaining the image formed by the laser beam passing through one of the multi-slit diaphragms at the optical output end, it further includes:

[0031] Coarsely adjust the multiple multi-slit diaphragms so that the deviation between the central position of each multi-slit diaphragm and the theoretical central position is within a preset position range.

[0032] According to the collimation device and method of the multi-slit diaphragm in the neutron scattering spectrometer proposed in the embodiment of the present invention, wherein the device includes: an optical input end, an optical output end, a motion component connected to the multi-slit diaphragm, and a computer; the optical input end is used to output a laser beam, the laser beam passes through one of the multi-slit diaphragms to the optical output end, and the optical output end is used to form an image according to the laser beam; the computer is used to obtain the actual central position of the multi-slit diaphragm corresponding to the image according to each image; and control the movement of the multiple motion components according to the multiple actual central positions to adjust the multiple multi-slit diaphragms to align with the actual central position of one of the multi-slit diaphragms as a reference. To achieve the alignment of the relative positions of multiple multi-slit diaphragms in the neutron scattering spectrometer, improve the relative position accuracy of multiple multi-slit diaphragms in the neutron scattering spectrometer, and further improve the measurement accuracy of the neutron scattering spectrometer.

[0033] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become readily understood from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0035] Figure 1 is a schematic layout structure diagram of multiple multi-slit diaphragms in a neutron scattering spectrometer in the prior art;

[0036] Figure 2 is a block schematic diagram of a collimation device for a multi-slit diaphragm in a neutron scattering spectrometer proposed in an embodiment of the present invention;

[0037] Figure 3 is a schematic structure diagram of a multi-slit diaphragm in the prior art;

[0038] Figure 4 is an image obtained at the optical output end of a collimation device for a multi-slit diaphragm in a neutron scattering spectrometer proposed in an embodiment of the present invention;

[0039] Figure 5 is Figure 4 the integral light intensity curve corresponding to the image in;

[0040] Figure 6 is a peak process diagram of obtaining an integral light intensity curve in a collimation device for a multi-slit diaphragm in a neutron scattering spectrometer proposed in an embodiment of the present invention.

[0041] Figure 7 is a schematic optical path diagram of a collimation device for a multi-slit diaphragm in a neutron scattering spectrometer proposed in an embodiment of the present invention;

[0042] Figure 8 is a schematic optical path diagram of a collimation device for a multi-slit diaphragm in a neutron scattering spectrometer proposed in another embodiment of the present invention;

[0043] Figure 9 is a schematic optical path diagram of a collimation device for a multi-slit diaphragm in a neutron scattering spectrometer proposed in yet another embodiment of the present invention;

[0044] Figure 10 is a schematic optical path diagram of a collimation device for a multi-slit diaphragm in a neutron scattering spectrometer proposed in still another embodiment of the present invention;

[0045] Figure 11It is a flowchart of the collimation method of the multi-slit aperture in the neutron scattering spectrometer proposed by the embodiments of the present invention. Detailed implementation manners

[0046] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0048] Currently, in a neutron scattering spectrometer, there are generally 12 multi-slit apertures 103, and the 12 multi-slit apertures are arranged in sequence (as Figure 1 shown), but limited by the measurement accuracy of the instrument itself, traditional measurement instruments (such as laser trackers, tool theodolites, levels, etc.) and conventional collimation measurement methods cannot achieve this accuracy index, and the accuracy of the relative positions between the 12 multi-slit apertures 103 cannot meet the requirements (the accuracy requirement for the relative position (X) is within ±25 μm). Therefore, the relative position accuracy between the 12 multi-slit apertures 103 is made to reach within ±25 μm by the collimation device of the multi-slit aperture in the neutron scattering spectrometer proposed by the embodiments of the present invention. Among them, the multi-slit apertures are all of an eight-slit structure, the distance between the slits is equal, and the 12 multi-slit apertures are unevenly distributed on the optical path, and the distance between adjacent multi-slit apertures is 12.32 meters.

[0049] Figure 2 It is a block diagram of the collimation device of the multi-slit aperture in the neutron scattering spectrometer proposed by the embodiments of the present invention. As Figure 2 shown, the device 100 includes: an optical input end 101, an optical output end 102, a motion component 104 connected to the multi-slit aperture 103, and a computer 105;

[0050] The optical input end 101 is used to output a laser beam. The laser beam passes through one of the multi-slit diaphragms 103 to the optical output end 102, and the optical output end 102 is used to form an image according to the laser beam.

[0051] The computer 105 is used to obtain the actual central position of the multi-slit diaphragm 103 corresponding to each image according to each image; and control the movement of the plurality of motion components 104 according to the plurality of actual central positions to adjust the plurality of multi-slit diaphragms 103 to align with the actual central position of one of the multi-slit diaphragms 103 as a reference.

[0052] It should be noted that before collimating the relative positions of the 12 multi-slit diaphragms 103 using the collimation device 100 of the multi-slit diaphragm in this neutron spectrometer, it is first necessary to collimate and adjust the multi-slit diaphragm 103 to an accuracy with a deviation of ±0.1 mm from the theoretical center through a laser tracker. That is to say, transfer the mechanical centers of the 12 multi-slit diaphragms 103 to an external reference point and perform preliminary collimation adjustment on the positions of the 12 multi-slit diaphragms 103.

[0053] Next, ensure that one of the multi-slit diaphragms 103 is in the optical path of the collimation device 100, output a laser beam through the optical input end 101, form an image through the optical output end 102, and the computer 105 processes the image to obtain the actual central position of the multi-slit diaphragm 103 corresponding to the image. Repeat this step in sequence to obtain the actual central positions of the 12 multi-slit diaphragms 103. Furthermore, taking one of the multi-slit diaphragms 103 as a reference, adjust the motion component 104 so that the relative position accuracy of the 12 multi-slit diaphragms 103 reaches within ±25 μm.

[0054] Specifically, the actual central position of the multi-slit diaphragm is obtained through the image, that is, the processing method of the image is as follows: The detailed diagram of the multi-slit diaphragm 103 is as Figure 3 shown. The multi-slit diaphragm 103 includes 8 slits. Furthermore, the imaging of the multi-slit diaphragm 103 at the optical output end 102 includes 8 bright lines (as Figure 4 shown). Convert the image into a two-dimensional data matrix and integrate it along the extending direction of the bright line to obtain a light intensity curve (as Figure 5As shown in the figure, there are 8 large transmission peaks and some small diffraction peaks around the large peaks on the curve. Regarding the above curve as a curve with periodically oscillating peaks, after Fourier transform, it becomes a frequency-domain curve with multiple peaks. The reciprocal of the position (frequency) of the peak with the smallest frequency (the largest period) is the spacing between two peak positions of the oscillating peak before the transform. Then, half of the spacing can be approximated as the full width at half maximum W of the curve before the transform. Due to the influence of diffraction, the 8 large transmission peaks may not be symmetric Gaussian peaks. Therefore, a new algorithm is adopted in this solution to determine the peak positions. Suppose there is a line I(n) (n is a positive integer) with N points (as shown in Figure 6 ), and there are 8 peaks with a full width at half maximum (FWHM) of W (W is an integer) evenly distributed on the line. We access the points from the (W + 1)-th point to the (N - W)-th point. When and This means that the integrals in the intervals (n - W, n) and (n + 1, n + W) are almost the same. At this time, the coordinate of the peak position is:

[0055] n peak = n + a1 / (a1 + a2), where

[0056] Thus, through the above method, the positions of the 8 peaks in Figure 5 can be found. Furthermore, by averaging the positions of the 8 peaks, the actual center position of the multi-slit aperture 103 can be obtained. It should be noted that the actual center position of the multi-slit aperture 103 is the position in the camera coordinate system.

[0057] It can be understood that the method of calculating the positions of the 8 peaks of the multi-slit aperture 103 through the light intensity curve can also be other calculation methods well known in the art. The present invention does not make specific limitations on this.

[0058] Table 112 Actual center position table of multi-slit apertures

[0059]

[0060] Thus, for example, taking the actual center position of the 1st multi-slit aperture as a reference, the deviations of the actual center positions of other multi-slit apertures from the actual center position of the 1st multi-slit aperture are 3.985, 7.093, -0.983, -0.54, 4.614, 1.666, 3.269, 0.429, 1.856, 2.696, -4.166 in sequence. Furthermore, these deviations are corrected to the 2nd - 12th multi-slit apertures. Finally, the actual center positions of the 1st - 12th multi-slit apertures are aligned with the 1st multi-slit aperture as a reference.

[0061] It should be noted that in the actual operation process, an actual center position with a small deviation value from the theoretical center position can be selected as a reference for adjustment. Among them, since the absolute position has been calibrated by the theoretical center position before adjusting the relative positions of the multiple slit diaphragms, the absolute position meets the accuracy requirements, and this solution is to make the relative positions of the multiple slit diaphragms meet the accuracy requirements.

[0062] In addition, the moving component 104 can be a high-precision electric translation stage, which is a two-axis translation stage and requires high motion accuracy, including that the positioning accuracy and the repeat positioning accuracy should reach the micron level. The multiple slits are fixed on the translation stage and can achieve high-precision displacement motion in the elevation and lateral directions along with the translation stage.

[0063] The optical path in the device 100 will be introduced in detail below.

[0064] Optionally, as Figure 7 shown, the optical input end 101 includes:

[0065] The first laser 1, the first diaphragm 2, the first attenuation mirror 3, the beam expander 4, and the second diaphragm 5. The first laser 1 is used to emit a laser beam, and the laser beam passes through the first diaphragm 2, the first attenuation mirror 3, the beam expander 4, and the second diaphragm 5 in sequence to the multi-slit diaphragm 103.

[0066] Among them, the first laser 1 is a semiconductor laser with fiber-coupled output. In order to reduce the divergence angle, a collimator is configured at the end. The wavelength is 405 nm, the power is 5 mW, the divergence angle is less than 0.5 mrad, and the beam waist radius is 3 mm. The first attenuation mirror 3 is a neutral density filter. The beam expander 4 is of the Galilean type. The first diaphragm 2 and the second diaphragm 5 are used to limit the light path of the light beam, so that the laser beam emitted by the first laser 1 can be located on this light path. The purpose of the first attenuation mirror 3 is to reduce the output power of the laser and attenuate the laser beam to avoid over-saturation when imaging at the final optical output end 102. The function of the beam expander 4 is to expand the incident light spot from 3 mm to 54 mm so that the laser beam is expanded enough to cover the multi-slit diaphragm 103.

[0067] Optionally, as Figure 8 shown, the optical input end 101 further includes:

[0068] The first optical path adjustment component and the third diaphragm 6. The laser beam passing through the second diaphragm 5 passes through the first optical path adjustment component and the third diaphragm 6 in sequence and then reaches the multi-slit diaphragm 103.

[0069] It should be noted that when the length of the device 100 set in the lateral direction in the figure is limited, the corresponding functions can be realized by adjusting the optical path.

[0070] Optionally, the first optical path adjustment component includes:

[0071] The first reflector 7, the fourth diaphragm 8 and the second reflector 9. The first reflector 7 is configured to reflect the laser beam that has passed through the second diaphragm 5 to the fourth diaphragm 8, and the second reflector 9 is configured to reflect the laser beam that has passed through the fourth diaphragm 8 to the third diaphragm 6.

[0072] Optionally, as Figure 9 shown, the optical input end 101 further includes: a semi-transparent and semi-reflective lens 10, a second attenuation mirror 11 and a position sensitive detector 12;

[0073] The semi-transparent and semi-reflective lens 10 is located between the laser 1 and the first diaphragm 2 and is configured to transmit a part of the laser beam emitted by the laser 1 as the first laser beam and reflect a part as the second laser beam. The first laser beam is configured to pass through the multi-slit diaphragm 103 to form an image at the optical output end 102. The second laser beam passes through the second attenuation mirror 11 to the position sensitive detector 12.

[0074] Wherein, the semi-transparent and semi-reflective lens 10 is a non-polarizing composite cube semi-transparent and semi-reflective mirror, with anti-reflection films coated on 4 side faces. The deflection angle of the transmitted beam is less than 3 arcmin. The laser beam emitted from the first laser 1 is split into two parts after passing through the composite cube semi-transparent and semi-reflective mirror 10. The beam splitting ratio of the reflected light and the transmitted light is 5:5. One of the laser beams is reflected by the composite cube semi-transparent and semi-reflective mirror 10 and then reflected by the second optical path adjustment component 13 and enters the position sensitive detector 12, thereby performing real-time monitoring on the position of the laser. The position sensitive detector 12 is a two-dimensional position sensitive detector, with an effective area of 9*9 mm, a resolution of 1 μm, and a response spectrum of 400 nm - 1100 nm. In order to enable the position sensitive detector 12 to respond effectively and avoid oversaturation, a neutral density filter 11 is placed in front of it, effectively reducing the power of the laser beam entering the position sensitive detector 12. The other laser beam directly passes through the composite cube semi-transparent and semi-reflective mirror 10 and then enters the beam expander 4. The beam expander 4 is a Galilean beam expander, and its function is to expand the incident light spot from 3 mm to 54 mm. The expanded laser passes through the first reflector 7 and the second reflector 9 and then passes through the multi-slit diaphragm 103 to form an image on the optical output end 102.

[0075] Optionally, as Figure 9 shown, the optical input end 101 further includes: a second optical path adjustment component 13, which is located on the propagation path of the second laser beam. The second laser beam sequentially passes through the second optical path adjustment component 13, the second attenuation mirror 11 to the position sensitive detector 12.

[0076] That is to say, when the optical path length setting of the device 100 in the longitudinal direction in the figure is limited, the second optical path adjustment component 13 can be used to adjust the optical path to meet the actual space requirements.

[0077] Optionally, as Figure 10 shown, the optical input end 101 further includes: a second laser 14 and a third optical path adjustment component 15;

[0078] The second laser 14 is configured to emit a laser beam to the third optical path adjustment component 15 when the first laser 1 fails. The laser beam is incident on the semi-reflective semi-transmissive lens 10 after being adjusted by the third optical path adjustment component 15, forming a first laser beam and a second laser beam.

[0079] That is to say, the second laser 14 is a backup laser. When the position sensitive detector 12 detects a problem with the position of the laser beam emitted by the first laser 1, that is, when the first laser 1 fails, the second laser 14 is started. Only one of the first laser 1 and the second laser 14 can be used. This can double the service life of the entire optical path.

[0080] Optionally, as Figure 10 shown, the optical output end 102 includes: a fifth aperture 16, a lens 17, and a camera 18. The laser beam passing through the multi-slit aperture 103 is imaged on the camera 18 after passing through the fifth aperture 16 and the lens 17 in sequence.

[0081] Among them, the lens 17 can be a high-precision double telecentric lens, which has the advantages of small distortion and high resolution. The camera 18 can be a CCD camera or a CMOS camera. When the camera is a CMOS camera, the size is 1.1 inches, the resolution of the CMOS is 12 million pixels (4096 * 3000 pixel), and the size of a single pixel is 3.45 * 3.45 microns.

[0082] The laser emitted by the laser passes through the beam expander 4 to obtain a collimated parallel light beam. The laser beam is adjusted to be coaxial with the center of the multi-slit aperture 103 by using an aperture. The laser beam finally forms a Fraunhofer strip diffraction spot image on the CCD or CMOS after passing through the multi-slit aperture 103. The center of all the multi-slit aperture strip spots can be obtained through image processing. Taking one multi-slit aperture as a reference, the deviation of the remaining multi-slit apertures relative to the center of the reference multi-slit aperture is obtained, and this deviation is reduced by a high-precision electric translation stage, and finally the multi-slit aperture is aligned within ±25 μm.

[0083] Figure 11 is a flowchart of the collimation method of the multi-slit aperture in the neutron scattering spectrometer proposed by the embodiment of the present invention. This method is implemented based on the collimation device of the multi-slit aperture in the neutron scattering spectrometer as described above. As Figure 11 shown, this method includes the following steps:

[0084] S101, obtaining an image formed by the laser beam passing through one of the multi-slit apertures at the optical output end;

[0085] S102. Obtain the actual central position of the multi-slit aperture according to the image;

[0086] Repeat the above steps. S103. Obtain the actual central position corresponding to each multi-slit aperture;

[0087] S104. Control the movement of the movement components connected to each multi-slit aperture to adjust the multiple multi-slit apertures to align with the actual central position of one of the multi-slit apertures as a reference.

[0088] Optionally, S102 obtaining the actual central position of the multi-slit aperture according to the image includes:

[0089] Obtain the two-dimensional grayscale matrix of the image;

[0090] Integrate the data along the slit direction of the multi-slit aperture according to the two-dimensional grayscale matrix to obtain the light intensity curve;

[0091] Obtain multiple peak positions of the multi-slit aperture according to the light intensity curve;

[0092] Obtain the central position of the multi-slit aperture according to the multiple peak positions.

[0093] Optionally, before obtaining the image formed by the laser beam passing through one of the multi-slit apertures at the optical output end, it further includes:

[0094] Coarsely adjust the multiple multi-slit apertures so that the deviation between the central positions of the multiple multi-slit apertures and the theoretical central position is within the preset position range.

[0095] It should be noted that before collimating the relative positions of the 12 multi-slit apertures 103 using the collimation device 100 of the multi-slit aperture in this neutron scattering spectrometer, it is first necessary to collimate and adjust the multi-slit aperture 103 to an accuracy with a deviation of ±0.1 mm from the theoretical center through a laser tracker. That is, transfer the mechanical centers of the 12 multi-slit apertures 103 to an external reference point and perform preliminary collimation adjustment on the positions of the 12 multi-slit apertures 103. In addition, the laser beam is also collimated through the aperture to coincide with the theoretical center of the multi-slit aperture 103.

[0096] Then, ensure that one of the multi-slit apertures 103 is in the optical path of the collimation device 100, output the laser beam through the optical input end 101, and form an image through the optical output end 102. The computer 105 processes this image to obtain the actual central position of the multi-slit aperture 103 corresponding to this image. Repeat this step in sequence to obtain the actual central positions of the 12 multi-slit apertures 103. Furthermore, with one of the multi-slit apertures 103 as a reference, adjust the movement component 104 so that the relative position accuracy of the 12 multi-slit apertures 103 reaches within ±25 μm.

[0097] Specifically, the actual central position of the multi-slit aperture is obtained through an image, that is, the image is processed as follows: A detailed view of the multi-slit aperture 103 is as Figure 3 shown. The multi-slit aperture 103 includes 8 slits. Furthermore, the imaging of the multi-slit aperture 103 at the optical output end 102 includes 8 bright lines (as Figure 4 shown). The image is converted into a two-dimensional data matrix and integrated along the extending direction of the bright lines to obtain an intensity curve (as Figure 5 shown). There are 8 large transmission peaks and some small diffraction peaks around the large peaks on the curve. Regarding the above curve as a curve with periodically oscillating peaks, after Fourier transform, it becomes a frequency-domain curve with multiple peaks. The reciprocal of the position (frequency) of the peak with the smallest frequency (the largest period) is the distance between two peak positions of the oscillating peaks before transformation. Then, half of the distance can be approximated as the full width at half maximum W of the curve before transformation. Due to the influence of diffraction, the 8 large transmission peaks may not be symmetric Gaussian peaks. Therefore, a new algorithm is adopted in this solution to determine the peak positions. Suppose there is a line I(n) (n is a positive integer) with N points (as Figure 6 shown), and there are 8 peaks with a uniform full width at half maximum (FWHM) of W (W is an integer) evenly distributed on the line. We access the points from the (W + 1)-th point to the (N - W)-th point. When and this means that the integrals in the intervals (n - W, n) and (n + 1, n + W) are almost the same. At this time, the coordinate of the peak position is:

[0098] n peak = n + a1 / (a1 + a2), where

[0099] Thus, through the above method, the positions of the 8 peaks in Figure 5 can be found. Furthermore, by averaging the positions of the 8 peaks, the actual central position of the multi-slit aperture 103 can be obtained. It should be noted that the actual central position of the multi-slit aperture 103 is the position in the camera coordinate system.

[0100] It can be understood that the method of calculating the positions of the 8 peaks of the multi-slit aperture 103 through the intensity curve can also be other calculation methods well known in the art. The present invention does not make specific limitations thereto.

[0101] Table 2 Actual Central Position Table of 12 Multi-slit Apertures

[0102]

[0103] Thus, for example, taking the actual center position of the first multi-slit aperture as a reference, the deviations of the actual center positions of the other multi-slit apertures from the actual center position of the first multi-slit aperture are 3.985, 7.093, -0.983, -0.54, 4.614, 1.666, 3.269, 0.429, 1.856, 2.696, -4.166 in sequence. Furthermore, these deviations are corrected onto 2 - 12 multi-slit apertures. Finally, the actual center positions of the 1 - 12 multi-slit apertures are aligned with the first multi-slit aperture as the reference.

[0104] It should be noted that during the actual operation process, an actual center position with a relatively small deviation value from the theoretical center position can be selected as the reference for adjustment. Among them, since the absolute position has been calibrated by the theoretical center position before adjusting the relative positions of the multi-slit apertures, thus, the absolute position meets the accuracy requirements, and this solution is to make the relative positions of the multi-slit apertures meet the accuracy requirements.

[0105] Thus, compared with the traditional measurement method using a laser tracker and optical instruments, laser collimation can achieve micron-level high-precision collimation of multi-slit apertures and can realize real-time on-line position monitoring of multi-slit apertures. This system and method are also applicable to high-precision laser on-line collimation measurement and monitoring of other similar components. Among them, laser collimation utilizes the advantages of the good directivity and long coherence distance of the laser. After expanding its beam, it is used as the background light to pass through 12 multi-slit apertures, enabling the multi-slit apertures to be imaged on a CCD camera or a CMOS camera. The center of the multi-slit apertures is obtained through image processing, and micron-level accuracy collimation of the multi-slit apertures can be achieved through relevant algorithms.

[0106] In summary, according to the collimation device and method for multi-slit apertures in a neutron scattering spectrometer proposed in the embodiments of the present invention, the device includes: an optical input end, an optical output end, a motion component connected to the multi-slit aperture, and a computer; the optical input end is used to output a laser beam, the laser beam passes through one of the multi-slit apertures to the optical output end, and the optical output end is used to form an image according to the laser beam; the computer is used to obtain the actual center position of the multi-slit aperture corresponding to the image according to each image; and control the movement of multiple motion components according to multiple actual center positions to adjust multiple multi-slit apertures to be aligned with the actual center position of one of the multi-slit apertures as the reference. To achieve the alignment of the relative positions of multiple multi-slit apertures in the neutron scattering spectrometer, improve the relative position accuracy of multiple multi-slit apertures in the neutron scattering spectrometer, and further improve the measurement accuracy of the neutron scattering spectrometer.

[0107] It should be understood that the various forms of processes shown above can be used, with steps reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is imposed herein.

[0108] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A collimation device for a multi-slit aperture in a neutron scattering spectrometer, characterized in that, Comprising: An optical input end, an optical output end, a moving component connected to a multi-slit aperture, and a computer; The optical input end is used to output a laser beam, the laser beam passes through one of the multi-slit apertures to the optical output end, and the optical output end is used to form an image according to the laser beam; The computer is used to obtain the actual central position of the multi-slit aperture corresponding to the image according to each image; And control the movement of multiple moving components according to multiple actual central positions to adjust multiple multi-slit apertures to align with the actual central position of one of the multi-slit apertures as a reference; wherein, the image is a bright spot image corresponding to the multi-slit aperture obtained by the optical output end when any one of the multi-slit apertures is in the optical path of the collimating device, and the actual central position is the position of the average value of the peaks of each bright spot in the bright spot image in the camera coordinate system; When the moving component adjusts the movement of multiple multi-slit apertures to be collimated and aligned, control the adjustment position of the current multi-slit aperture to eliminate the deviation between the actual central position of the current multi-slit aperture and the actual central position of the multi-slit aperture used as a reference.

2. The collimation device of the multi-slit aperture in the neutron scattering spectrometer according to claim 1, characterized in that, The optical input end includes: A first laser, a first aperture, a first attenuator, a beam expander, and a second aperture. The first laser is used to emit the laser beam, and the laser beam sequentially passes through the first aperture, the first attenuator, the beam expander, and the second aperture to the multi-slit aperture.

3. The collimation device of the multi-slit aperture in the neutron scattering spectrometer according to claim 2, characterized in that, Further comprising: A first optical path adjustment component and a third aperture. The laser beam passing through the second aperture then sequentially passes through the first optical path adjustment component and the third aperture and then reaches the multi-slit aperture.

4. The collimation device of the multi-slit aperture in the neutron scattering spectrometer according to claim 3, characterized in that, The first optical path adjustment component includes: A first mirror, a fourth aperture, and a second mirror. The first mirror is used to reflect the laser beam passing through the second aperture to the fourth aperture, and the second mirror is used to reflect the laser beam passing through the fourth aperture to the third aperture.

5. The collimation device of the multi-slit aperture in the neutron scattering spectrometer according to claim 2, characterized in that, Further comprising: A beam splitter, a second attenuator, and a position sensitive detector; The beam splitter is located between the laser and the first aperture, and is used to transmit a part of the laser beam emitted by the laser as a first laser beam and reflect a part as a second laser beam; the first laser beam is used to pass through the multi-slit aperture to the optical output end to form an image; the second laser beam passes through the second attenuator to the position sensitive detector.

6. The collimation device of the multi-slit aperture in the neutron scattering spectrometer according to claim 5, characterized in that, Further comprising: A second optical path adjustment component, which is located on the propagation path of the second laser beam, and the second laser beam sequentially passes through the second optical path adjustment component and the second attenuator to the position sensitive detector.

7. The collimation device of the multi-slit aperture in the neutron scattering spectrometer according to claim 5, characterized in that, Further comprising: A second laser and a third optical path adjustment component; The second laser is used to emit a laser beam to the third optical path adjustment component when the first laser fails, and the laser beam is adjusted by the third optical path adjustment component and then incident on the beam splitter to form the first laser beam and the second laser beam.

8. The collimation device of the multi-slit aperture in the neutron scattering spectrometer according to claim 1, characterized in that, The optical output end includes: a fifth diaphragm, a lens, and a camera. The laser beam passing through the multi-slit diaphragm sequentially passes through the fifth diaphragm and the lens and then forms an image on the camera.

9. A collimation method for a multi-slit aperture in a neutron scattering spectrometer, characterized in that, Implemented based on the collimation device of the multi-slit diaphragm in the neutron scattering spectrometer according to any one of claims 1-8, comprising the following steps: Obtain an image formed by the laser beam passing through one of the multi-slit diaphragms at the optical output end; Obtain the actual central position of the multi-slit diaphragm according to the image; Repeat the above steps to obtain the actual central position corresponding to each multi-slit diaphragm; Control the movement of the movement components connected to each multi-slit diaphragm to adjust the multiple multi-slit diaphragms to align with the actual central position of one of the multi-slit diaphragms as a reference; Wherein, the image is a bright spot image corresponding to the multi-slit diaphragm obtained by the optical output end when any one of the multi-slit diaphragms is in the optical path of the collimation device, and the actual central position is the position of the average value of the peaks of each bright spot in the bright spot image in the camera coordinates; When the movement components adjust the multiple multi-slit diaphragms to move and collimate and align, control the adjustment position of the current multi-slit diaphragm to eliminate the deviation between the actual central position of the current multi-slit diaphragm and the actual central position of the multi-slit diaphragm used as a reference.

10. The collimation method of the multi-slit aperture in the neutron scattering spectrometer according to claim 9, characterized in that, The obtaining the actual central position of the multi-slit diaphragm according to the image includes: Obtain the two-dimensional gray level matrix of the image; Integrate the data along the slit direction of the multi-slit diaphragm according to the two-dimensional gray level matrix to obtain the light intensity curve; Obtain multiple peak positions of the multi-slit diaphragm according to the light intensity curve; Obtain the central position of the multi-slit diaphragm according to the multiple peak positions.

11. The collimation method of the multi-slit aperture in the neutron scattering spectrometer according to claim 9, characterized in that, Before obtaining the image formed by the laser beam passing through one of the multi-slit diaphragms at the optical output end, it further includes: Coarsely adjust the multiple multi-slit diaphragms so that the deviation between the central position of each multi-slit diaphragm and the theoretical central position is within a preset position range.

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