Multi-channel KB microscope with double energy points and high coaxiality

Abstract

The invention discloses a multi-channel KB microscope with double energy points and high coaxiality. The multi-channel KB microscope comprises a plurality of KB reflectors Mi which are oppositely arranged in the meridian direction and a plurality of KB reflectors Sj which are oppositely arranged in the sagittal direction, the system further comprises a KB reflecting mirror Sj'which is arranged opposite to the KB reflecting mirror Sj in the sagittal direction. The mirror surface of the KB reflecting mirror Mi, the mirror surface of the KB reflecting mirror Sj and the mirror surface of the KB reflecting mirror Sj 'are plated with different multi-layer films in a partitioned mode. The plurality of KB reflectors Mi, the plurality of KB reflectors Sj and the plurality of KB reflectors Sj'are combined pairwise to form a multi-channel X-ray image in matrix arrangement. According to the multi-channel KB microscope with the double energy points and the high coaxiality, the difference of the observation visual angle of each energy point is remarkably reduced from a few degrees to a zero point few degrees, meanwhile, the capability of carrying out quasi-coaxial multi-channel observation at two different energy points is achieved, and the application range of a sixteen-channel KB system in ICF physical experiments is effectively expanded.

Description

Technical Field

[0001] The invention relates to the technical field of multi-channel X-ray microscopes for ICF plasma diagnosis, in particular to a multi-channel KB microscope with dual energy points and high coaxiality. Background Art

[0002] The multi-channel KB microscopic imaging system is a key device for time-framing high-temperature and high-density plasma diagnosis in inertial confinement fusion (ICF) research. In conjunction with a framing camera, it can achieve time resolution by responding to multiple images in sequence at different times, showing the instantaneous state of plasma in the two-dimensional space direction, and has been widely used in OMEGA in the United States.

[0003] At present, the optical configuration of multi-channel KB microscopy at home and abroad is actually a deformation of the early multi-channel KB system structure of the OMEGA device, that is, the mirrors are arranged in pairs to form a mirror pair. Taking the 16-channel KB microscopy system as an example, its objective lens structure is as follows: Figure 1 As shown in the figure, four reflectors are arranged opposite to each other in the meridian direction and four reflectors are arranged opposite to each other in the sagittal direction. Figure 2 As shown, under grazing incidence conditions, there is a viewing angle difference of about several degrees between the observation axes of the two reflectors arranged relative to each other through the cone core, resulting in the target capsule for actual diagnosis being observed along multiple different angles. In addition, the actual target capsule structure is relatively complex, so the consistency of the observed data is poor, making it difficult to meet the needs of the development trend of precision laser fusion diagnosis. Summary of the invention

[0004] The purpose of the present invention is to provide a dual-energy point high coaxiality multi-channel KB microscope, which solves the problem that the objective lenses of the traditional multi-channel KB system are arranged in pairs in the meridian and sagittal directions, the KB objective lenses are closely arranged in space, and the installation and adjustment are difficult. The multi-channel KB system proposed by the present invention is composed of a reflection mirror array arranged opposite to each other in the meridian direction and a reflection mirror array arranged opposite to each other and opposite to each other in the sagittal direction, and there is no mutual interference in space, and the installation and adjustment difficulty is significantly reduced.

[0005] To achieve the above object, the present invention provides a dual-energy point high coaxiality multi-channel KB microscope, comprising a plurality of KB reflectors Mi arranged opposite to each other in the meridian direction and a plurality of KB reflectors Sj arranged opposite to each other in the sagittal direction; and further comprising a KB reflector Sj' arranged opposite to the KB reflector Sj in the sagittal direction, wherein the mirror surface of the KB reflector Mi, the mirror surface of the KB reflector Sj and the mirror surface of the KB reflector Sj' are all plated with different multilayer films by partitioning;

[0006] A plurality of the KB reflectors Mi and a plurality of the KB reflectors Sj and Sj' are combined in pairs to form a multi-channel X-ray image arranged in a matrix.

[0007] Preferably, the imaging relationship of the KB reflector Sj and the KB reflector Sj' in their respective sagittal planes is the same as the imaging relationship of the KB reflector Mi in their respective meridian planes.

[0008] Preferably, the imaging relationship of the KB reflector Mi in each meridian plane conforms to the following equation:

[0009]

[0010] Among them, u is the distance from the object point to the center of the KB reflector, that is, the object distance, v is the distance from the image point to the center of the KB reflector, θ is the angle between the tangent line at the center of the KB reflector and the reflected light, that is, the grazing incidence angle, f is the focal length, and R is the radius of curvature of the reflector surface.

[0011] Preferably, the observation viewing angle β of the KB reflector Mi, the KB reflector Sj and the KB reflector Sj' conforms to the following formula:

[0012] (u+v)sinβ+v·2θ·cosβ=L (2)

[0013] Among them, u is the distance from the object point to the center of the KB reflector, that is, the object distance, v is the distance from the image point to the center of the KB reflector, θ is the angle between the tangent line at the center of the KB reflector and the reflected light, that is, the grazing incidence angle, f is the focal length, and R is the radius of curvature of the reflector surface.

[0014] Preferably, the multilayer film is used for high-energy X-ray backlight imaging of 4.75keV and 6.7keV characteristic lines, and the multilayer film is composed of a periodic alternating combination of high atomic number materials and low atomic number materials;

[0015] A higher reflectivity than X-rays at a specific energy point is obtained by Bragg diffraction, and the Bragg diffraction formula is as follows:

[0016] 2dsinθ=kλ (3)

[0017] Where d is the period thickness of the multilayer film, k is the diffraction order, and λ is the operating wavelength.

[0018] Preferably, the multilayer film adopts an X-ray multilayer film structure working in a dual-energy point common mirror. For the 4.75keV low-energy channel, the multilayer film is composed of a double-periodic structure with an upper layer for 4.75keV high reflection and a lower layer for 8.05keV high reflection; for the 6.7keV high-energy channel, the multilayer film is composed of a three-periodic structure with two upper layers for 6.7keV high reflection and a lower layer for 8.05keV high reflection.

[0019] Preferably, the reflectivity of the actual multilayer film is measured at 8.05 keV using an X-ray diffractometer, and the genetic algorithm program in the REFS software is used to fit the measured data to obtain a reflectivity-angle variation curve, and the thin film parameters of the multilayer film, including periodic thickness, material ratio and roughness, are obtained by fitting the reflectivity-angle variation curve.

[0020] Preferably, according to the film parameters, the multilayer film structure is deposited on an ultra-smooth spherical reflector with a roughness of 0.3 nm using a DC magnetron sputtering technique.

[0021] Therefore, the present invention adopts the above-mentioned dual-energy point high coaxiality multi-channel KB microscope, and the beneficial effects are as follows:

[0022] (1) The present invention arranges multiple reflectors working at grazing incidence angles facing each other, thereby reducing the change in observation angle by an order of magnitude compared to the traditional multi-channel KB structure, while minimizing the difference in observation angle and ensuring the backlight brightness during multi-channel imaging.

[0023] (2) The present invention also adds a sixteen-channel structure of 4.75keV and 6.7keV, so that it can work at dual energy points.

[0024] (3) The multi-period multilayer film structure provided in the present invention improves the angular bandwidth and energy spectrum resolution while also ensuring the imaging field of view and brightness.

[0025] (4) The present invention realizes dynamic grid imaging of eight time-frames on the SG-III prototype laser device using only a single backlight, and the spatial resolution within the ±200μm field of view is 4-10μm, which proves the feasibility of the proposed small-size backlight and small-azimuth observation method, that is, the KB mirror can operate at several keV energy points on a kilojoule device with only a single backlight.

[0026] (5) Based on the present invention, the measurement of more energy points and more channels can be achieved by changing the specific reflector layout or optimizing the combination design of the thin film structure, providing a new means for high spatiotemporal resolution and quasi-monoenergetic backlight imaging of laser plasma X-rays.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of a sixteen-channel KB microscopic imaging system of a multi-channel KB microscope background technology with dual energy points and high coaxiality according to the present invention;

[0029] Figure 2 It is a light path structure diagram of a sixteen-channel KB microscopic imaging system of a multi-channel KB microscope background technology with dual energy points and high coaxiality according to the present invention;

[0030] Figure 3 Schematic diagram of imaging of an eight-channel KB microscope of an embodiment of a dual-energy point high coaxiality multi-channel KB microscope of the present invention, wherein (a) is an eight-channel KB structure, and (b) is a schematic diagram of a meridian direction of a small azimuth multi-channel grazing incidence structure;

[0031] Figure 4 Schematic diagram of the image point position of a sixteen-channel KB microscope of an embodiment of a dual-energy point high coaxiality multi-channel KB microscope of the present invention, wherein (a) is a schematic diagram of the sagittal direction of a two-color sixteen-channel grazing incidence structure, and (b) is a schematic diagram of a two-color sixteen-channel KB microscope;

[0032] Figure 5 The optical simulation software of a dual-energy point high coaxiality multi-channel KB microscope embodiment of the present invention simulates the spatial resolution of the M1S1 channel, wherein (a) is the spatial resolution of the M1 channel, and (b) is the spatial resolution of the S1 channel;

[0033] Figure 6 Schematic diagram of a multi-layer film structure of a dual-energy point high coaxiality multi-channel KB microscope embodiment of the present invention, wherein (a) is an X-ray multi-layer film structure of dual-energy point co-mirror operation, and (b) is a change in reflectivity of the M3 multi-layer film with grazing incidence angle when the multi-layer film operates at different energy points;

[0034] Figure 7 It is a multilayer film fitting curve of a dual-energy point high coaxiality multi-channel KB microscope embodiment of the present invention, wherein (a) is the measured value and fitting curve of the reflectivity of the multilayer film of the low-energy channel, and (b) is the measured value and fitting curve of the reflectivity of the multilayer film of the high-energy channel;

[0035] Figure 8 1 is a curve showing the change of reflectivity of a multilayer film with energy in an embodiment of a multi-channel KB microscope with dual energy points and high coaxiality according to the present invention, wherein (a) is a curve showing the change of reflectivity of a multilayer film with energy in a low energy channel, and (b) is a curve showing the change of reflectivity of a multilayer film with energy in a high energy channel;

[0036] Fig. 9It is a 600-mesh gold grid image obtained by an X-ray CCD with an exposure time of 20 minutes in an embodiment of a dual-energy point high coaxiality multi-channel KB microscope of the present invention;

[0037] Fig.10 It is the imaging spatial resolution of a dual-energy point high coaxiality multi-channel KB microscope embodiment of the present invention, wherein (a) is the grid image of the M2 and S1' channels, and (b) is the calibrated spatial resolution of the grid image of the M2 and S1' channels. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0039] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] A dual-energy point high coaxiality multi-channel KB microscope comprises a plurality of KB reflectors Mi arranged opposite to each other in the meridian direction and a plurality of KB reflectors Sj arranged opposite to each other in the sagittal direction. In order to achieve observation at a small azimuth angle, the present invention proposes that the plurality of reflectors are arranged opposite to each other, and at the same time, since each mirror surface works at a grazing incidence angle, each imaging channel can observe the same part of the object. Figure 3 As shown in (a), take the eight-channel KB with eight imaging channels as an example: X-rays are reflected by the KB reflector Mi in the meridian direction and the KB reflector Sj in the sagittal direction to form image A. ij , eight image points are located on the four microstrips of the frame camera in the form of a 2×4 matrix. The optical path of X-rays in the meridian direction is as follows Figure 3 As shown in (b), the sagittal direction is similar.

[0041] The imaging relationship of the KB reflectors Sj and Sj' in the sagittal direction in their respective sagittal planes is the same as the imaging relationship of the KB reflectors Mi in the meridional direction in their respective meridional planes. The imaging relationship of the KB reflectors Mi in the meridional direction in their respective meridional planes conforms to the following equation:

[0042]

[0043] Among them, the central axis is the line connecting the object to the center of the image point, u is the distance from the object point to the center of a KB reflector, that is, the object distance, v is the distance from the image point to the center of a KB reflector, θ is the angle between the tangent line at the center of a KB reflector and the reflected light, that is, the grazing incidence angle, f is the focal length, and R is the radius of curvature of the reflector surface.

[0044] Figure 3 In (b), Li is the distance between the image formed by each reflector and the central optical axis, Φ is the target size, st is the distance from the backlight source to the sample target, and Δs is the distance between the backlight sources M1 and M4.

[0045] A dual-energy point high coaxiality multi-channel KB microscope also includes an increase in the sagittal direction with Figure 1 The KB reflector Sj' which is equivalent to and arranged opposite to the KB reflector Sj is as follows: Figure 4 As shown, two reflective mirrors S1' and S2' are arranged opposite to S1 and S2. Although only two mirrors are added, the imaging channels are increased from eight to sixteen, and the mirror surfaces of KB reflector Mi, KB reflector Sj and KB reflector Sj' are all coated with different multi-layer films in different areas to distinguish energy points, forming a two-color multi-channel form.

[0046] The final layout of the two-color sixteen-channel KB microscope is as follows Figure 4 As shown in (a), a plurality of KB reflectors Mi in the meridional direction and the KB reflectors Sj and Sj' in the sagittal direction are combined in pairs to form a multi-channel X-ray image arranged in a matrix.

[0047] Its schematic diagram in the sagittal direction is as follows Figure 4 As shown in (b), in actual applications, it is only necessary to change the image plane and the backlight position to obtain X-ray images at different energies. The opposite arrangement of the mirrors in the sagittal direction allows for a larger observation angle, and the self-luminescence can be distinguished from the backlight. The 2×4 matrix form used in this embodiment is for coupling the microstrip of the framed camera. In actual use, different combinations of reflector matrices in the meridian and sagittal directions can be used according to different recording surface conditions, thereby having a wider range of application scenarios.

[0048] Table 1 shows the geometric structure parameters of the small azimuth two-color sixteen-channel KB microscope. The spacing between adjacent image points in the meridian direction is 16 mm, while the spacing between four rows of image points in the sagittal direction are 16 mm, 32 mm and 16 mm respectively. The spacing between different energy points is set to 32 mm in order to clearly distinguish different energy points.

[0049] Among them, the object distance u is selected to be around 200μm, mainly to avoid the objective lens being too close to the target and interfering with the laser beam; the magnification is set to about 8-12 times to avoid the image resolution being limited by the detector pixels, so the magnification is set to about 8-12 times; the M4 curvature radius is different from other mirrors, mainly by changing the curvature radius to change its grazing incidence angle to avoid M4 from interfering with other light paths. The microscope selects a grazing incidence angle θ close to 1.0° to ensure imaging quality and multilayer film reflectivity. Based on these parameter conditions, the microscope geometric light collection efficiency can reach 8.5×10 -7 sr.

[0050] Table 1 Geometric parameters of small-azimuth two-color sixteen-channel KB microscope

[0051]

[0052]

[0053] In addition, the observation angle β of KB reflector Mi, KB reflector Sj and KB reflector Sj' conforms to the following formula:

[0054] (u+v)sinβ+v·2θ·cosβ=L (2)

[0055] Among them, u is the distance from the object point to the center of the KB reflector, that is, the object distance, v is the distance from the image point to the center of the KB reflector, θ is the angle between the tangent line at the center of the KB reflector and the reflected light, that is, the grazing incidence angle, f is the focal length, and R is the radius of curvature of the reflector surface.

[0056] It can be seen from Table 1 that the differences in the observation angles of S1 and S1' and S2 and S2' in the sagittal direction are 5.36° and 5.04° respectively, while the observation angles of adjacent reflectors arranged opposite to each other in the meridian direction vary as follows: β M1-M2 =0.17°, β M2-M3 = 0.17° and β M3-M4 =0.12°, the difference in observation angles of the adjacent reflectors S1 and S2 arranged in the sagittal direction is 0.16°, and the maximum difference in observation angles of the structure arranged in series facing each other (i.e., β M1-M4 ) is only about 0.46°.

[0057] It can be seen that the observation angle difference of the multi-channel system proposed in this embodiment is reduced by nearly one order of magnitude compared with the traditional structure, which effectively reduces the requirements for the focal spot size of the backlight source. According to the structural parameters given in Table 1, when the distance from the backlight source to the sample target is st = 10mm, the focal spot of the backlight source required to illuminate different channels of each energy point is widened by nearly 70μm, thereby ensuring the energy density and brightness of the X-ray light source.

[0058] This embodiment simulates the resolution of the imaging of the grid by the reflectors M1 and S1. The grid period is 30 μm, the grid line width is 4.2 μm and it is placed at the object point. The results are as follows: Figure 5 As shown in (a), it can be seen that the grid lines are sharp at the center, but as the field of view increases, the grid lines gradually blur and the corresponding resolution deteriorates. The distance corresponding to the 90%-10% change in image brightness near the grid line from the peak to the trough is used as the evaluation standard, and the change of its spatial resolution in the meridian direction with the field of view is obtained as follows Figure 5 As shown in (b), the resolution is better than 3μm in the central field of view and about 5μm in the ±100μm field of view. The resolution in the sagittal direction is similar to that in the meridional direction.

[0059] Thin film imaging design and production

[0060] In this embodiment, the low energy channel and the high energy channel are realized by coating different multilayer films on the reflective mirror surface. The multilayer film is used for high energy X-ray backlight imaging of the characteristic lines of Ti (4.75keV) and Fe (6.7keV). The multilayer film is composed of a periodic alternating combination of high atomic number materials (high z) and low atomic number materials (low z); a higher reflectivity than the specific energy point X-ray is obtained by Bragg diffraction. The Bragg diffraction formula is as follows:

[0061] 2dsinθ=kλ (3)

[0062] Where d is the period thickness of the multilayer film, k is the diffraction order, and λ is the operating wavelength.

[0063] Since the grazing incidence structure has serious diffraction in the visible light band, especially for more complex multi-channel configurations, the objective lens assembly in the laboratory can only be completed with the help of X-rays. Therefore, the multilayer film of the present invention adopts an X-ray multilayer film structure with dual energy points working in the same mirror.

[0064] like Figure 6 As shown in (a), W and C are multilayer film materials, d is the period thickness of the multilayer film, and N is the number of multilayer film periods. For the 4.75keV low-energy channel, the multilayer film consists of a double-period structure with an upper layer for 4.75keV high reflection and a lower layer for 8.05keV (Cu Kα line) high reflection. The Cu Kα line is generated by a commonly used Cu target X-ray tube, has high brightness, and still maintains a certain transmittance in the atmospheric environment. Therefore, it can be used for the working energy of the objective lens adjustment, and will not affect the reflectivity of the top physical experiment energy point.

[0065] For the 6.7keV high-energy channel, due to its narrower angular bandwidth, in order to ensure the imaging brightness in different angle fields of view, the multilayer film consists of a three-periodic structure with the upper two layers for 6.7keV high reflection and the lower layer for 8.05keV high reflection.

[0066] Although the upper two layers use the same material pair combination, the period thickness is slightly different, thereby expanding the angular bandwidth for 6.7keV. Figure 6 (b) is the curve of the reflectivity of the multilayer film of the M3 reflector changing with the angle. It can be seen that the peak positions of the multilayer film at 8.05keV and 4.75keV coincide and are consistent with the design value, both at 1.235°; 8keV has a narrower angular bandwidth than 4.75keV, and the reflectivity is more sensitive to the angle deviation of the adjustment, and the focal depth or depth of field is smaller, so the adjustment accuracy requirements are more stringent, so as to ensure the reflection efficiency and spatial resolution when working at 4.75keV.

[0067] Taking the two energy points of the reflector M3 as an example, the reflectivity of the actual multilayer film can be measured at 8.05keV (Cu Kα line) using an X-ray diffractometer (Bruker D8DISCOVER), and the genetic algorithm program in the REFS software is used to fit the measured data to obtain the reflectivity-angle variation curve, such as Figure 7 As shown in Figure 2, the measured data and the fitting results are in good agreement in terms of peak shape and peak height. At the same time, the reflectivity versus angle curve obtained by the fitting is used to obtain the film parameters of the multilayer film, including actual film parameters such as period thickness, material ratio, and roughness, as shown in Table 2. The symbol γ represents the ratio of material W to period thickness. Then, according to the film parameters, all multilayer film structures are deposited on an ultra-smooth spherical reflector with a roughness of 0.3 nm using DC magnetron sputtering technology.

[0068] Table 2 Multilayer film structural parameters obtained by fitting based on XRD measured data

[0069]

[0070]

[0071] Based on Table 2, we can draw the curves of the reflectivity of the low-energy channel and high-energy channel multilayer films as a function of energy, such as Figure 8 As shown. It can be seen that the reflectivity at 4.75keV and 6.7keV is greater than 50%, and the bandwidth is greater than 1keV, which can fully cover the Ti and Fe characteristic lines. The imaging area is basically within the highlight area, and the brightness is guaranteed. The reflectivity requirement at 8.05keV for debugging is lower, but it is also greater than 25%. X-rays below 2.5keV can be suppressed by placing a filter on the optical path.

[0072] Objective lens integration and debugging: Figure 5As shown in the figure, the spatial resolution of the KB objective lens deteriorates significantly as the field of view deviates. Especially for multi-channel KB microscopes, it is necessary to make the field of view of all channels with the best spatial resolution aim at the same object point, and at the same time, the spacing between each image point should be adjusted to match the microstrip of the framing camera. In the small azimuth KB structure of this embodiment, each reflector can be adjusted independently in the meridian direction, and the two reflectors arranged relatively in the sagittal direction are coupled to each other. The serial multi-channel design and the precision assembly based on the wedge cone center are adopted, which is more flexible than the traditional adjustment method.

[0073] The four reflectors in the meridian direction are fixed independently on a set of six-dimensional adjustment frames, and then the posture of each reflector is adjusted independently in the 8.05keV energy point X-ray debugging experiment to find the best field of view and expected image point spacing in the meridian direction. The reflectors in the sagittal direction are grouped in pairs, first leaning against high-precision optical prisms with specific sizes and cone angles to form two independent pairs of mirrors, and then fixed on a set of six-dimensional adjustment frames for independent debugging to find the best field of view and expected image point spacing in the sagittal direction.

[0074] In the experiment, the spatial resolution marker used was a 600-mesh gold grid (Gilder, G600HSS) with a line width of 6μm and a period spacing of 42μm. There was a marking hole in the grid with a length and width of about 170μm (as shown by the arrow) to determine the specific field of view position. The operating voltage and current of the Cu target X-ray tube were 30kV and 28mA, respectively. The detection device used was a 2048×2048 pixel X-ray CCD (SOPHIA-XO:2048B) with a pixel size of about 15μm×15μm. Since the CCD detection surface size was only about 30mm×30mm, which was smaller than the image point arrangement range of the sixteen channels (48mm×64mm), it was placed on an electrically controlled three-dimensional translation stage, the CCD position was moved and multiple exposures were made, the spatial resolution was evaluated in real time by the clarity of the grid, and the image point spacing was calibrated by the distance of the marking holes of each channel imaging. The debugging of all reflectors was completed separately, and the imaging results are shown in the figure. Fig. 9 As shown, the exposure time is 20 minutes, and the grid position remains unchanged during the exposure process.

[0075] It can be seen that within the range of about 400-500μm field of view, all channels can form a clear image of the grid with a line width of 6μm. The target surface of the Cu target X-ray museum has an angle of about 6° with the output light axis, which makes the vertical axis size of the backlight source of different channels different, especially the sagittal reflector with large azimuth angle difference, resulting in differences in the backlight illumination field of view of the low-energy channel and the high-energy channel, and the reflectivity of each channel at 8.05keV is not the same, so there will be certain differences in brightness between the channels.

[0076] According to Figure 5(b) The consistent "10%-90%" standard is used to calibrate the spatial resolution of the final image. Take the imaging of the M2 and S1' channels as an example ( Fig.10 (a)). The spatial resolution measured along the meridian direction is as follows Fig.10 As shown in (b), the best resolution near the marking hole is about 3μm, the field of view within ±75μm is better than 5μm, the resolution in the sagittal direction is close to that in the meridian direction, and the best point of the fitting resolution is marked with an orange cross.

[0077] The actual magnification can be obtained by dividing the grid period captured by the CCD by the grid period obtained by the scanning electron microscope. The magnifications of M2 and S1' are 10.48× and 11.13×, respectively, which are almost the same as the theoretical magnifications. The intervals between two adjacent images in the horizontal direction are 15.97mm, 15.68mm, 15.82mm and 15.40mm, respectively; the intervals between two adjacent images in the sagittal direction are 15.74mm, 32.11mm and 15.93mm, respectively, which are consistent with the design values.

[0078] Therefore, the present invention adopts the above-mentioned dual-energy point high-coaxiality multi-channel KB microscope, and through the sequential arrangement of the reflecting mirrors facing each other, the angle of the incident light axis of each mirror surface is changed from several degrees in the past to a few tenths of a degree, which significantly reduces the requirements for the size of the backlight source, greatly increases the backlight power density, and makes high-energy density medium and high-energy imaging possible, or no longer requires multiple backlights to illuminate different imaging channels.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A dual-energy point high coaxiality multi-channel KB microscope, characterized in that: It includes a plurality of KB reflectors Mi arranged opposite to each other in the meridian direction and a plurality of KB reflectors Sj arranged opposite to each other in the sagittal direction; it also includes a KB reflector Sj' arranged opposite to the KB reflector Sj in the sagittal direction, and the mirror surfaces of the KB reflector Mi, the KB reflector Sj and the KB reflector Sj' are all plated with different multilayer films by partitioning; A plurality of the KB reflectors Mi and a plurality of the KB reflectors Sj and Sj' are combined in pairs to form a multi-channel X-ray image arranged in a matrix.

2. A dual-energy point high coaxiality multi-channel KB microscope according to claim 1, characterized in that: The imaging relationship of the KB reflector Sj and the KB reflector Sj' in their respective sagittal planes is the same as the imaging relationship of the KB reflector Mi in their respective meridian planes.

3. A dual-energy point high coaxiality multi-channel KB microscope according to claim 2, characterized in that: The imaging relationship of the KB reflector Mi in each meridian plane conforms to the following equation: Among them, u is the distance from the object point to the center of the KB reflector, that is, the object distance, v is the distance from the image point to the center of the KB reflector, θ is the angle between the tangent line at the center of the KB reflector and the reflected light, that is, the grazing incidence angle, f is the focal length, and R is the radius of curvature of the reflector surface.

4. A dual-energy point high coaxiality multi-channel KB microscope according to claim 3, characterized in that: The observation angle β of the KB reflector Mi, the KB reflector Sj and the KB reflector Sj' conforms to the following formula: (u+v)sinβ+v·2θ·cosβ=L (2) Among them, u is the distance from the object point to the center of the KB reflector, that is, the object distance, v is the distance from the image point to the center of the KB reflector, θ is the angle between the tangent line at the center of the KB reflector and the reflected light, that is, the grazing incidence angle, f is the focal length, and R is the radius of curvature of the reflector surface.

5. A dual-energy point high coaxiality multi-channel KB microscope according to claim 4, characterized in that: The multilayer film is used for high-energy X-ray backlight imaging of 4.75keV and 6.7keV characteristic lines, and the multilayer film is composed of a periodic alternating combination of high atomic number materials and low atomic number materials; A higher reflectivity than X-rays at a specific energy point is obtained by Bragg diffraction, and the Bragg diffraction formula is as follows: 2dsinθ=kλ (3) Wherein, d is the period thickness of the multilayer film, k is the diffraction order, and λ is the operating wavelength.

6. A dual-energy-point high-coaxiality multi-channel KB microscope according to claim 5, characterized in that: The multilayer film adopts an X-ray multilayer film structure working in a dual-energy point common mirror. For the 4.75keV low-energy channel, the multilayer film is composed of a double-periodic structure with an upper layer for 4.75keV high reflection and a lower layer for 8.05keV high reflection; for the 6.7keV high-energy channel, the multilayer film is composed of a three-periodic structure with two upper layers for 6.7keV high reflection and a lower layer for 8.05keV high reflection.

7. A dual-energy point high coaxiality multi-channel KB microscope according to claim 6, characterized in that: The reflectivity of the actual multilayer film was measured at 8.05keV using an X-ray diffractometer, and the genetic algorithm program in the REFS software was used to fit the measured data to obtain a reflectivity-angle curve. The thin film parameters of the multilayer film, including periodic thickness, material ratio and roughness, were obtained by fitting the reflectivity-angle curve.

8. The dual-energy-point high-coaxiality multi-channel KB microscope according to claim 7, characterized in that: According to the film parameters, the multilayer film structure is deposited on an ultra-smooth spherical mirror with a roughness of 0.3 nm using DC magnetron sputtering technology.

Images