A dual-energy, high-coaxial multichannel KB microscope

Abstract

This invention discloses a dual-energy-point, highly coaxial, multi-channel KB microscope, comprising multiple KB mirrors Mi arranged facing each other in the meridional direction and multiple KB mirrors Sj arranged facing each other in the sagittal direction; it also includes KB mirrors Sj' arranged opposite to the KB mirrors Sj in the sagittal direction. The mirror surfaces of KB mirrors Mi, Sj, and Sj' are all coated with different multilayer films in different areas. Multiple KB mirrors Mi are combined in pairs with multiple KB mirrors Sj and Sj' to form a matrix-arranged multi-channel X-ray image. This invention, employing the aforementioned dual-energy-point, highly coaxial, multi-channel KB microscope, significantly reduces the difference in observation angle at each energy point from several degrees to a fraction of a degree, while simultaneously possessing the ability to perform quasi-coaxial multi-channel observations at two different energy points, effectively expanding the application range of the sixteen-channel KB system in ICF physics experiments.

Description

Technical Field

[0001] This invention relates to the field of multi-channel X-ray microscopy for ICF plasma diagnostics, and in particular to a dual-energy point high coaxiality multi-channel KB microscope. Background Technology

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

[0003] Currently, the optical configurations of multi-channel KB microscopy imaging systems both domestically and internationally are essentially variations of the early multi-channel KB system structure of the OMEGA device, employing mirrors arranged in pairs to form a mirror pair. Taking a sixteen-channel KB microscopy imaging system as an example, its objective lens structure is as follows: Figure 1 As shown, four reflectors are arranged facing each other in the meridional direction, and four reflectors are arranged facing each other in the sagittal direction. Its top view is as follows. Figure 2 As shown, under grazing incidence, there is a difference of about a few degrees in the viewing angle between the two mirrors arranged opposite each other through the cone core. This results in the target pellet being observed from multiple different angles. In addition, the actual target pellet has a relatively complex structure, so the consistency of the observation data is poor, which makes it difficult to meet the needs of the trend of precision development in laser fusion diagnosis. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-energy, high-coaxial multichannel KB microscope, which solves the problem that traditional multichannel KB systems have objectives arranged in pairs in the meridional and sagittal directions, resulting in a dense spatial arrangement of KB objectives and making assembly and adjustment difficult. The multichannel KB system proposed in this invention is composed of a mirror array arranged facing each other in the meridional direction and a mirror array arranged facing and opposite each other in the sagittal direction, which does not interfere with each other in space and significantly reduces the difficulty of assembly and adjustment.

[0005] To achieve the above objectives, the present invention provides a dual-energy point high coaxiality multichannel KB microscope, comprising multiple KB mirrors Mi arranged facing each other in the meridional direction and multiple KB mirrors Sj arranged facing each other in the sagittal direction; it also includes KB mirrors Sj' arranged opposite to the KB mirrors Sj in the sagittal direction, wherein the mirror surfaces of the KB mirrors Mi, Sj, and Sj' are all coated with different multilayer films in different areas;

[0006] Multiple KB reflectors Mi are combined in pairs with multiple KB reflectors Sj and Sj' to form a matrix-arranged multi-channel X-ray image.

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

[0008] Preferably, the imaging relationship of the KB reflectors Mi in their respective meridional planes conforms to the following equation:

[0009]

[0010] Where u is the distance from the object point to the center of the KB mirror surface, i.e., the object distance; v is the distance from the image point to the center of the KB mirror surface; θ is the angle between the tangent at the center of the KB mirror surface and the reflected ray, i.e., the grazing angle of incidence; f is the focal length; and R is the radius of curvature of the mirror surface.

[0011] Preferably, the observation 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] Where u is the distance from the object point to the center of the KB mirror surface, i.e., the object distance; v is the distance from the image point to the center of the KB mirror surface; θ is the angle between the tangent at the center of the KB mirror surface and the reflected ray, i.e., the grazing angle of incidence; f is the focal length; and R is the radius of curvature of the mirror surface.

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

[0015] High reflectivity compared to X-rays at a specific energy point is obtained through Bragg diffraction, and the Bragg diffraction formula is as follows:

[0016] 2dsinθ=kλ (3)

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

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

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

[0020] Preferably, based on the thin film parameters, a multilayer film structure is deposited on an ultra-smooth spherical mirror with a roughness of 0.3 nm using DC magnetron sputtering technology.

[0021] Therefore, the present invention employs the aforementioned dual-energy-point, high-coaxiality multichannel KB microscope, which offers the following advantages:

[0022] (1) By arranging multiple reflectors that work at grazing incidence angles in opposite directions, the present invention reduces the change in observation angle by an order of magnitude compared to the traditional multi-channel KB structure. This minimizes the difference in observation angle while ensuring the backlight brightness during multi-channel imaging.

[0023] (2) The present invention also adds a sixteen-channel structure with 4.75keV and 6.7keV, enabling it to work at a dual energy point.

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

[0025] (4) The present invention achieves dynamic grid imaging with time-division of eight time points using only a single backlight on the Shenguang three prototype laser device. 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 angle observation method. That is, the KB mirror can be used at several keV energy points on a kilojoule device with only a single backlight.

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

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a sixteen-channel KB microscopy imaging system for dual-energy point high coaxiality multi-channel KB microscopy background technology according to the present invention;

[0029] Figure 2 This is an optical path diagram of a sixteen-channel KB microscopic imaging system for dual-energy point high coaxiality multi-channel KB microscopy background technology according to the present invention.

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

[0031] Figure 4 This is a schematic diagram of the image point position of a sixteen-channel KB microscope according to 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 arc direction of the two-color sixteen-channel grazing incidence structure, and (b) is a schematic diagram of the two-color sixteen-channel KB microscope.

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

[0033] Figure 6 This is a schematic diagram of the multilayer film structure of a dual-energy point high coaxiality multichannel KB microscope according to an embodiment of the present invention, wherein (a) is the X-ray multilayer film structure working with dual-energy point co-mirror, and (b) is the change of reflectivity of M3 multilayer film with grazing incidence angle when working at different energy points respectively.

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

[0035] Figure 8 This is a curve showing the reflectance of a multilayer film as a function of energy in an embodiment of a dual-energy, high-coaxiality multichannel KB microscope of the present invention, wherein (a) is the curve showing the reflectance of a low-energy channel multilayer film as a function of energy, and (b) is the curve showing the reflectance of a high-energy channel multilayer film as a function of energy.

[0036] Figure 9This is a 600-mesh gold grid image obtained by an X-ray CCD with an exposure time of 20 min, representing an embodiment of a dual-energy, high-coaxiality, multi-channel KB microscope according to the present invention.

[0037] Figure 10 This invention relates to an embodiment of a dual-energy, high-coaxial multichannel KB microscope, where (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 Implementation

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only 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, high-coaxiality multichannel KB microscope includes multiple KB mirrors Mi arranged facing each other in the meridional direction and multiple KB mirrors Sj arranged facing each other in the sagittal direction. To achieve observation at small azimuth angles, this invention proposes arranging the multiple mirrors facing each other, and since each mirror operates at a grazing incidence angle, each imaging channel can observe the same part of the object. Figure 3 As shown in (a), taking an eight-channel KB with eight imaging channels as an example: X-rays are reflected by the KB mirror Mi in the meridional direction and the KB mirror Sj in the sagittal direction, respectively, to form image A. ij The eight image points are located on the four microstrips of the framing camera in a 2×4 matrix. The X-ray path in the meridional direction is as follows: Figure 3 As shown in (b), the direction of the arc is similar.

[0041] The imaging relationships of KB reflectors Sj and Sj' in the sagittal direction within their respective sagittal planes are the same as those of KB reflector Mi in the meridional direction within their respective meridional planes. The imaging relationships of KB reflector Mi in the meridional direction within their respective meridional planes conform to the following equation:

[0042]

[0043] Wherein, 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 certain KB mirror surface, i.e., the object distance, v is the distance from the image point to the center of a certain KB mirror surface, θ is the angle between the tangent at the center of a certain KB mirror surface and the reflected ray, i.e., the grazing angle of incidence, f is the focal length, and R is the radius of curvature of the mirror surface.

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

[0045] A dual-energy, high-coaxiality multichannel KB microscope also includes an increase in the sagittal direction with... Figure 1 An equivalent KB reflector Sj', arranged opposite to KB reflector Sj, such as... Figure 4 As shown, two reflecting mirrors S1' and S2' are arranged opposite each other in S1 and S2. Although only two mirrors are added, the imaging channels have increased from eight to sixteen. Furthermore, the mirrors Mi, Sj, and Sj' of the KB reflector are all coated with different multilayer films in different areas to distinguish the energy points and form a dual-color multichannel form.

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

[0047] Its schematic diagram in the sagittal direction is as follows Figure 4 As shown in (b), in practical applications, X-ray images at different energies can be obtained simply by changing the image plane and backlight positions. The opposing arrangement of mirrors in the sagittal direction results in a larger observation angle, which can distinguish between self-illumination and backlighting. The 2×4 matrix configuration used in this embodiment is for coupling the framing camera microstrip. In actual use, depending on different recording plane conditions, different combinations of mirror matrices in the meridional and sagittal directions can be used, thus enabling a wider range of applications.

[0048] Table 1 shows the geometric parameters of the small azimuth angle dual-color sixteen-channel KB microscope. The spacing between adjacent image points in the meridional direction is 16 mm, while the spacing between the four columns of image points in the sagittal direction is 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] The object distance u was chosen to be around 200 μm primarily to avoid interference between the objective lens and the laser beam due to the objective lens being too close to the target. The magnification was set to approximately 8-12 times to avoid image resolution being limited by detector pixels; the radius of curvature of M4 differed from other mirrors, primarily to alter its grazing incidence angle and prevent interference between M4 and other optical paths. A grazing incidence angle θ close to 1.0° was selected for this microscope to ensure image quality and multilayer film reflectivity. Based on these parameters, the microscope's geometric light-gathering efficiency can reach 8.5 × 10⁻⁶. -7 sr.

[0050] Table 1. Geometric parameters of the small azimuth angle dual-color sixteen-channel KB microscope

[0051]

[0052]

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

[0054] (u+v)sinβ+v·2θ·cosβ=L (2)

[0055] Where u is the distance from the object point to the center of the KB mirror surface, i.e., the object distance; v is the distance from the image point to the center of the KB mirror surface; θ is the angle between the tangent at the center of the KB mirror surface and the reflected ray, i.e., the grazing angle of incidence; f is the focal length; and R is the radius of curvature of the mirror surface.

[0056] As shown in Table 1, the differences in observation angles between S1 and S1' and between S2 and S2' in the sagittal direction are 5.36° and 5.04°, respectively, while the changes in observation angles of adjacent mirrors facing each other in the meridional direction are as follows: β M1-M2 =0.17°, β M2-M3 =0.17° and β M3-M4 =0.12°, the difference in observation angle between adjacent mirrors S1 and S2 arranged facing each other in the sagittal direction is 0.16°, and the maximum difference in observation angle of the facing tandem structure (i.e., β) is 0.12°. M1-M4 It is only about 0.46°.

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

[0058] This embodiment simulates the imaging resolution of a grid by mirrors M1 and S1, with a grid period of 30 μm and a grid line width of 4.2 μm placed at the object point. The results are as follows: Figure 5 As shown in (a), the grid lines are sharp at the center, but become blurred as the field of view increases, resulting in a decrease in resolution. Using the distance corresponding to 90%-10% of the image brightness variation from peak to trough near the grid lines as the evaluation criterion, the spatial resolution along the meridional direction as a function of the field of view is obtained as follows: Figure 5 As shown in (b), the resolution is better than 3 μm at the center field of view and about 5 μm at the ±100 μm field of view. The resolution in the sagittal direction is similar to that in the meridional direction.

[0059] Thin-film imaging design and fabrication

[0060] In this embodiment, the low-energy channel and the high-energy channel are achieved by depositing different multilayer films on the reflective mirror surface in sections. The multilayer films are used for high-energy X-ray backlight imaging of the Ti (4.75keV) and Fe (6.7keV) characteristic lines. The multilayer films are composed of periodically alternating combinations of high atomic number materials (high z) and low atomic number materials (low z). High reflectivity compared to X-rays at specific energy points is obtained through Bragg diffraction. The Bragg diffraction formula is as follows:

[0061] 2dsinθ=kλ (3)

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

[0063] Because grazing incidence structures exhibit severe diffraction in the visible light band, especially for more complex multi-channel configurations, objective lens assembly can only be performed in the laboratory using X-rays. Therefore, the multilayer film of this invention employs a dual-energy point co-mirror X-ray multilayer film structure.

[0064] like Figure 6 As shown in (a), W and C are multilayer film materials, d is the thickness of the multilayer film period, and N is the number of multilayer film periods. For the 4.75 keV low-energy channel, the multilayer film consists of a double-period structure with an upper layer for high reflectivity at 4.75 keV and a lower layer for high reflectivity at 8.05 keV (Cu Kα line). The Cu Kα line is generated by a commonly used Cu target X-ray tube, which has high brightness and maintains a certain transmittance in the atmospheric environment. Therefore, it can be used for the working energy of objective lens assembly without affecting the reflectivity of the top-layer physical experiment energy point.

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

[0066] Although the two upper layers use the same material pair, the period thickness is slightly different, thereby extending the angular bandwidth for 6.7keV. Figure 6 (b) shows the reflectivity curve of the multilayer film of the M3 mirror as a function of 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°. The angular bandwidth at 8keV is narrower than that at 4.75keV, and the reflectivity is more sensitive to the angle deviation of the assembly and adjustment. It also has a smaller depth of focus or depth of field, so the requirements for assembly and adjustment accuracy are more stringent, thus ensuring the reflection efficiency and spatial resolution when operating at 4.75keV.

[0067] Taking the two energy points of mirror M3 as an example, the reflectivity of the actual multilayer film can be measured at 8.05 keV (Cu Kα line) using an X-ray diffractometer (Bruker D8DISCOVER). The genetic algorithm program in REFS software is then used to fit the measured data to obtain the reflectivity versus angle curve, as shown below. Figure 7 As shown, the measured data and fitting results agree well in terms of peak shape and peak height. Simultaneously, the reflectivity versus angle curve obtained from this fitting yields the thin film parameters of the multilayer film, including actual thin 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, based on the thin film parameters, DC magnetron sputtering technology is used to deposit all multilayer film structures onto an ultra-smooth spherical mirror with a roughness of 0.3 nm.

[0068] Table 2 shows the multilayer film structure parameters obtained by fitting XRD measured data.

[0069]

[0070]

[0071] Based on Table 2, the reflectivity curves of low-energy and high-energy multilayer films as a function of energy can be plotted, such as... Figure 8 As shown, the reflectivity at 4.75 keV and 6.7 keV is greater than 50%, and the bandwidth is greater than 1 keV, which can completely cover the characteristic lines of Ti and Fe. The imaging area is basically within the high-brightness region, and the brightness is guaranteed. The reflectivity requirement at 8.05 keV, used for debugging, is lower, but still greater than 25%. X-rays below 2.5 keV can be suppressed by placing filters in the optical path.

[0072] Objective lens integration and adjustment: such as Figure 5As shown, the spatial resolution of KB objectives deteriorates significantly with field-of-view deviation, especially for multi-channel KB microscopes. This requires ensuring that all channels have optimal spatial resolution and are aligned with the same object point, while simultaneously adjusting the spacing between image points to match the microstrip of the framing camera. In this embodiment, the small azimuth KB structure allows independent adjustment of each mirror in the meridional direction, while the two mirrors arranged opposite each other in the sagittal direction are coupled together. The use of a tandem multi-channel design and precision assembly based on a wedge-shaped cone center provides greater flexibility compared to traditional adjustment methods.

[0073] The four meridional mirrors were independently fixed on a set of six-dimensional adjustment frames. Then, in an 8.05keV energy X-ray calibration experiment, the attitude of each mirror was independently adjusted to find the optimal field of view and the expected image point spacing in the meridional direction. The sagittal mirrors were paired up, first resting against high-precision machined optical prisms with specific dimensions and cone angles to form two independent mirror pairs. These pairs were then also fixed on a set of six-dimensional adjustment frames and independently adjusted to find the optimal field of view and the 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 linewidth of 6 μm and a periodic spacing of 42 μm. Each grid contained a marker hole approximately 170 μm in length and width (as shown by the arrow) to determine the specific field of view. The Cu target X-ray tube operated at 30 kV and 28 mA. The detection equipment used was a 2048 × 2048 pixel X-ray CCD (SOPHIA-XO:2048B) with a pixel size of approximately 15 μm × 15 μm. Since the CCD's detection surface size was only about 30 mm × 30 mm, smaller than the image point arrangement range of the sixteen channels (48 mm × 64 mm), it was placed on an electrically controlled three-dimensional translation stage. The CCD position was moved and multiple exposures were performed. The spatial resolution was evaluated in real time by the grid sharpness, and the image point spacing was calibrated by the distance between the marker holes in each channel. All mirrors were adjusted accordingly. The imaging results are shown below. Figure 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 a field of view of approximately 400-500 μm, all channels can form a clear image of a 6 μm linewidth grid. Due to the approximately 6° angle between the target surface of the Cu target X-ray chamber and the output optical axis, the vertical axis dimensions of the backlight source differ between channels. In particular, the sagittal reflectors, with their significant azimuth differences, result in variations in the backlight illumination field of view between low-energy and high-energy channels. Furthermore, the reflectivity of each channel at 8.05 keV is not identical, leading to certain differences in brightness between the channels.

[0076] According to Figure 5(b) A consistent "10%-90%" standard is used to calibrate the spatial resolution of the final image. This is illustrated using imaging of the M2 and S1' channels as an example. Figure 10 (a)). Spatial resolution obtained by measurement along the meridian direction is as follows: Figure 10 As shown in (b), the best resolution measured in this way is about 3 μm near the marked hole, the field of view within ±75 μm is better than 5 μm, the resolution in the sagittal direction is close to that in the meridional direction, and the point with the best fitted resolution is marked with an orange cross.

[0077] The actual magnification can be obtained by dividing the grid period of the CCD image by the grid period obtained from 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 spacing between two adjacent images in the horizontal direction is 15.97 mm, 15.68 mm, 15.82 mm, and 15.40 mm, respectively; the spacing between two adjacent images in the sagittal direction is 15.74 mm, 32.11 mm, and 15.93 mm, respectively, which are consistent with the design values.

[0078] Therefore, the present invention employs the above-mentioned dual-energy point high coaxiality multi-channel KB microscope, which, by arranging the mirrors in a sequential opposite direction, reduces the angle between the incident optical axes of each mirror from several degrees to a few tenths of a degree, significantly reducing the requirements for the size of the backlight source, greatly increasing the backlight power density, making high-energy-density medium-high-energy imaging possible, or eliminating the need for multiple backlights to illuminate different imaging channels.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A dual-energy, high-coaxiality multichannel KB microscope, characterized in that, It includes multiple KB reflectors Mi arranged facing each other in the meridional direction and multiple KB reflectors Sj arranged facing each other in the sagittal direction; it also includes KB reflectors arranged opposite to the KB reflectors Sj in the sagittal direction. The KB reflector Mi mirror, the KB reflector Sj mirror, and the KB reflector The mirror surfaces are all coated with different multi-layer films in different areas; Multiple KB reflectors Mi and multiple KB reflectors Sj, KB reflectors By combining pairs of X-ray images, a matrix arrangement is formed; The KB reflector Mi, the KB reflector Sj, and the KB reflector The observation angle β conforms to the following formula: （2） in, The distance from the object point to the center of the KB mirror surface is the object distance. The distance from the image point to the center of the KB mirror surface. Let be the angle between the tangent at the center of the KB mirror and the reflected ray, i.e., the grazing angle of incidence. Focal length Let be the radius of curvature of the mirror surface; The multilayer film is used for high-energy X-ray backlight imaging with characteristic lines of 4.75 keV and 6.7 keV. The multilayer film is composed of a periodic alternation of high atomic number materials and low atomic number materials. High reflectivity compared to X-rays at a specific energy point is obtained through Bragg diffraction, and the Bragg diffraction formula is as follows: 2dsinθ=kλ (3) Where d is the periodic thickness of the multilayer film, k is the diffraction order, and λ is the working wavelength; The multilayer film adopts a dual-energy point common mirror X-ray multilayer film structure. For the 4.75keV low-energy channel, the multilayer film consists of a double-period structure with an upper layer for high reflection at 4.75keV and a lower layer for high reflection at 8.05keV; for the 6.7keV high-energy channel, the multilayer film consists of a triple-period structure with two upper layers for high reflection at 6.7keV and a lower layer for high reflection at 8.05keV.

2. The dual-energy, high-coaxiality multichannel KB microscope according to claim 1, characterized in that, The KB reflector Sj, KB reflector The imaging relationship in their respective sagittal planes is the same as the imaging relationship of the KB reflector Mi in their respective meridional planes.

3. The dual-energy, high-coaxiality multichannel KB microscope according to claim 2, characterized in that, The imaging relationship of the KB reflector Mi in their respective meridional planes conforms to the following equation: （1） in, The distance from the object point to the center of the KB mirror surface is the object distance. The distance from the image point to the center of the KB mirror surface. Let be the angle between the tangent at the center of the KB mirror and the reflected ray, i.e., the grazing angle of incidence. Focal length Let be the radius of curvature of the mirror surface.

4. A dual-energy, high-coaxiality multichannel KB microscope according to claim 3, characterized in that, The reflectance of the actual multilayer film was measured at 8.05 keV using an X-ray diffractometer, and the genetic algorithm program in REFS software was used to fit the measured data to obtain the reflectance versus angle curve. The film parameters of the multilayer film, including period thickness, material ratio and roughness, were obtained by fitting the reflectance versus angle curve.

5. A dual-energy, high-coaxiality multichannel KB microscope according to claim 4, characterized in that, Based on the thin film parameters, a multilayer film structure was deposited on an ultra-smooth spherical mirror with a roughness of 0.3 nm using DC magnetron sputtering technology.

Images