A four-channel four-energy-point high-resolution x-ray microscopic imaging optical structure

Abstract

The application discloses a four-channel four-energy-point high-resolution X-ray microscopic imaging optical structure and relates to the technical field of X-ray optics, which is characterized in that: the four-channel four-energy-point high-resolution X-ray microscopic imaging optical structure comprises an object plane, four sets of reflecting mirror groups and an image plane, each set of reflecting mirror group is composed of two reflecting mirrors, the two reflecting mirrors are a first reflecting mirror and a second reflecting mirror respectively, the first reflecting mirror is close to the object plane, and the second reflecting mirror is close to the image plane; each set of reflecting mirror group corresponds to an imaging channel; a line connecting the center of the object plane and the center of the image plane is a central axis, and the four imaging channels are oppositely arranged on the two sides of the central axis. The application provides a four-channel four-energy-point high-resolution X-ray microscopic imaging optical structure. The technical problem that a grazing incidence double-mirror configuration is difficult to carry out multi-channel system integration is effectively solved. The requirement of inertial confinement fusion X-ray imaging diagnosis for multi-energy-point, multi-frame high-resolution imaging is further met.

Description

Technical Field

[0001] This invention relates to the field of X-ray optics, and more specifically, to a four-channel, four-energy-point high-resolution X-ray microscopy imaging optical structure. Background Technology

[0002] In laser inertial confinement fusion, deuterium-tritium fuel pellets, initially on the order of hundreds of micrometers, are compressed to tens of micrometers in an extremely short time, bringing the fuel to a state of high temperature and high pressure similar to that inside a planet. High-precision X-ray microscopic imaging diagnostic techniques or equipment have become key to gaining a deeper understanding of the implosion process and revealing physics problems that are still unclear at the ignition scale.

[0003] Multi-channel, multi-energy-point integrated X-ray microscopy optical structures can acquire multiple X-ray images with different energy point responses in a single laser ablation experiment. By coupling a high-temporal-resolution framing camera or streak camera to the backend, multiple dynamic evolution images can be obtained. Integrating the imaging channel system with multiple response energy points enables imaging diagnosis of the entire implosion compression process. Specifically, X-ray imaging channels with energy points below 5 keV help reveal the symmetry of the early implosion compression stage and reveal multiple physical parameters such as implosion velocity through implosion streamlines; X-ray channels with energy points from 5 keV to tens of keV help reveal the hotspot symmetry of the implosion stall stage.

[0004] Achieving multi-channel, multi-energy-point system integration of grazing-incidence X-ray microscopy optical structures presents significant technical challenges. This is because grazing-incidence X-ray microscopy optical structures are off-axis reflective optical structures operating at small angles, and their operating mode restricts the layout of the reflector substrate in three-dimensional space, posing difficulties for system integration.

[0005] Existing multi-channel, multi-energy X-ray imaging diagnostic structures mainly include the "pinhole array + spherical mirror" configuration, the multi-channel Kirkpatrick-Baez (KB) configuration, and the multi-channel toroidal mirror (i.e., tire mirror) configuration. These configurations use single-reflection imaging in a single focusing direction, which cannot effectively eliminate off-axis aberrations. The spatial resolution of these configurations is limited to above 5 μm, making it difficult to achieve high-resolution imaging over a large field of view. Existing high-resolution microscopic imaging optical structures mainly include the KBA configuration using double spherical mirrors and the Wolter configuration with a closed full-ring structure. Due to structural and spatial constraints, multi-channel system integration is difficult. Furthermore, in the above two structural forms, the line connecting the image point and the object point is coaxial with the rotation axis, and no method for multi-channel integration has yet been proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a high-resolution X-ray microscopy optical structure with four channels and four energy points, effectively solving the problem of difficulty in multi-channel system integration with grazing incidence dual-mirror configurations. The dual-mirror configuration significantly improves the resolution of a single imaging channel, enhancing the diagnostic capabilities of the microscopy imaging system. To meet the urgent need for multi-channel, multi-energy-point imaging systems in high-quality implosion process diagnosis, an image point position control method based on this optical structure is proposed. This satisfies the process diagnosis requirements for multiple observation energy points, multiple frames, and high-resolution imaging.

[0007] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a four-channel, four-energy-point high-resolution X-ray microscopy imaging optical structure, comprising an object plane, four sets of mirror groups, and an image plane. Each set of mirror groups consists of two mirrors, namely a first mirror and a second mirror. The first mirror is close to the object plane, and the second mirror is close to the image plane. Each set of mirror groups corresponds to an imaging channel. The horizontal line of the horizontal plane between the object plane and the image plane is the central axis. The four imaging channels are arranged opposite each other on both sides of the central axis. Each imaging channel forms an image point on the image plane, and there are object points on the object plane.

[0008] The present invention is further configured such that: the two imaging channels closer to the central axis of the four imaging channels adopt a smaller grazing incidence angle, corresponding to the high-energy imaging channels; the two channels farther from the central axis adopt a larger grazing incidence angle, corresponding to the low-energy imaging channels; and the difference in grazing incidence angle between the high-energy imaging channel and the low-energy imaging channel is greater than 1°.

[0009] The present invention is further configured such that: all four imaging channels adopt a double-mirror structure with two reflections; the double-mirror structure of each imaging channel can rotate around the object point as a whole, thereby adjusting the position of the image point on the image plane.

[0010] The present invention is further configured such that the method for adjusting the image point position of the grazing incidence dual-mirror structure in the imaging channel has the following steps:

[0011] S1: Design the vertical axis offset D_z of the image point;

[0012] S2: Rotate the double-mirror structure around the object point. Calculate the overall rotation angle θ of the double-mirror structure. ro ;

[0013] S3: Calculate the angle θ between the incident ray and the central axis. axis_new ;

[0014] S4: Calculate the imaging channel mirror spacing Sep;

[0015] S5: Determine whether the mirror spacing meets the thickness requirements of the mirror substrate; if it does, complete the design of this channel and proceed to the design of the next channel; if it does not, readjust the image point layout of this channel and iterate again in this process until the conditions are met.

[0016] The present invention is further configured such that the overall rotation angle θ of the dual-mirror structure of the imaging channel is... ro The calculation formula is:

[0017]

[0018] Where D_z is the perpendicular distance of the image point in the image plane, and s is the sum of the object and image distances of the optical system;

[0019] The angle θ between the incident ray and the central axis of the rotating imaging channel axis_new The calculation formula is:

[0020]

[0021] Where, θ axis_org It is the angle between the incident ray and the central axis in the initial state, M is the channel magnification, and θ0 is the grazing incident angle of the mirror;

[0022] The formula for calculating the distance from the first reflecting mirror to the central axis in a double-mirror structure is as follows:

[0023] B_z=uθ axis_new， (3)

[0024] Where u is the distance from the object point to the center of the first reflecting mirror;

[0025] Calculate the mirror spacing Sep of the imaging channel to ensure it meets the mirror substrate thickness requirements.

[0026] The calculation formula is as follows:

[0027]

[0028] Where, θ axis_new1 θ is the angle between the incident ray from channel 1 and the central axis. axis_new2 θ is the angle between the incident ray from channel 2 and the central axis. ro1 θ is the overall rotation angle of channel 1 within the meridional plane. ro2 It is the overall rotation angle of channel two within the meridional plane, θ 01 It is the grazing incidence angle of channel one, θ 02 It is the grazing incidence angle of channel two;

[0029] The thickness T of the ultra-smooth reflective substrate and the spacing between channel one and channel two should satisfy the following relationship:

[0030] Sep 1,2 >T(5)

[0031] In summary, this invention offers the following advantages: It proposes a four-channel, four-energy-point high-resolution X-ray microscopy optical structure. This allows for the system integration of four channels and four different energy points. Each imaging channel employs a dual-mirror reflective configuration, exhibiting high spatial resolution imaging characteristics, with a spatial resolution better than 3 μm. Furthermore, it proposes a technique for adjusting the image point position in the grazing-incidence dual-mirror configuration.

[0032] This invention effectively overcomes the technical challenges of insufficient imaging resolution in existing technologies such as the "pinhole array + spherical mirror" configuration, the multi-channel Kirkpatrick-Baez (KB) configuration, and the multi-channel toroidal mirror (i.e., tire mirror) configuration. It further meets the requirements of inertial confinement fusion X-ray imaging diagnosis for multiple observation energy points, multiple frames, and high-resolution imaging. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the four-channel, four-energy-point X-ray microscopy imaging optical structure according to an embodiment of the present invention;

[0034] Figure 2 This is an imaging optical path diagram of the four-channel, four-energy-point X-ray microscopy imaging optical structure according to an embodiment of the present invention;

[0035] Figure 3 This is a geometric schematic diagram of single-channel imaging image point adjustment according to an embodiment of the present invention;

[0036] Figure 4 This is a flowchart of the image point position adjustment process for a grazing incidence dual-mirror configuration according to an embodiment of the present invention;

[0037] Figure 5 This is the spatial resolution curve (geometric speckle radius RMS value) of channel 1 in the embodiment of the present invention;

[0038] Figure 6 This is the spatial resolution curve (geometric dispersion radius RMS value) of channel 2 in the embodiment of the present invention;

[0039] Figure 7 This is the spatial resolution curve (geometric dispersion radius RMS value) of channel 3 in the embodiment of the present invention;

[0040] Figure 8 This is the spatial resolution curve (geometric dispersion radius RMS value) of channel 4 in the embodiment of the present invention. Detailed Implementation

[0041] The following is in conjunction with the appendix Figure 1-8 The present invention will be described in further detail below.

[0042] Example: A four-channel, four-energy-point high-resolution X-ray microscopy imaging optical structure, such as... Figure 1-8 As shown, it includes an object plane, four sets of mirror groups, and an image plane. Each set of mirror groups consists of two mirrors, namely the first mirror and the second mirror. The first mirror is closer to the object plane, and the second mirror is closer to the image plane. Each set of mirror groups corresponds to an imaging channel. The horizontal line of the horizontal plane between the object plane and the image plane is the central axis. The four imaging channels are arranged opposite each other on both sides of the central axis. Each imaging channel forms an image point on the image plane, and there is an object point on the object plane.

[0043] The two imaging channels closest to the central axis use a smaller grazing incidence angle, corresponding to the high-energy imaging channels; the two channels farther from the central axis use a larger grazing incidence angle, corresponding to the low-energy imaging channels; the grazing incidence angle between the high-energy imaging channels and the low-energy imaging channels should maintain a large difference, generally greater than 1°.

[0044] All four imaging channels employ a dual-mirror structure with double reflections. The dual-mirror structure of each imaging channel can rotate around the object point to adjust the image point position on the image plane. Using double reflection imaging in a single focusing direction significantly reduces off-axis aberrations and improves the imaging quality of the edge fields of view. For a single imaging channel, the dual-mirror structure can be considered a rigid whole, and the image point position on the image plane can be adjusted by rotating around the object point, ensuring that the image point distribution and spacing meet the requirements of a framing camera's strip layout or other detector image plane layouts.

[0045] The spacing between each imaging channel is calculated using the formula and must meet the thickness requirements of the reflector substrate. Based on the current processing level of ultra-precision reflectors, the channel spacing T should be greater than 10mm.

[0046] The steps for adjusting the image point position of the grazing incidence dual-mirror structure in the imaging channel are as follows:

[0047] S1: Design the vertical axis offset D_z of the image point;

[0048] S2: Rotate the double-mirror structure around the object point. Calculate the overall rotation angle θ of the double-mirror structure. ro ;

[0049] S3: Calculate the angle θ between the incident ray and the central axis. axis_new ;

[0050] S4: Calculate the imaging channel mirror spacing Sep;

[0051] S5: Determine whether the mirror spacing meets the thickness requirements of the mirror substrate; if it does, complete the design of this channel and proceed to the design of the next channel; if it does not, readjust the image point layout of this channel and iterate again in this process until the conditions are met.

[0052] The overall rotation angle θ of the dual-mirror structure of the imaging channel ro The calculation formula is:

[0053]

[0054] Where D_z is the perpendicular distance of the image point in the image plane, and s is the sum of the object and image distances of the optical system;

[0055] The angle θ between the incident ray and the central axis of the rotating imaging channel axis_new The calculation formula is:

[0056]

[0057] Where, θ axis_org It is the angle between the incident ray and the central axis in the initial state (the initial state refers to the state where the image point is located on the central axis, that is, the center of the image plane), M is the channel magnification, and θ0 is the grazing incidence angle of the mirror.

[0058] The formula for calculating the distance from the first reflecting mirror to the central axis in a double-mirror structure is as follows:

[0059] B_z=uθ axis_new， (3)

[0060] Where u is the distance from the object point to the center of the first reflecting mirror;

[0061] Calculate the mirror spacing Sep of the imaging channel to ensure it meets the mirror substrate thickness requirements.

[0062] The calculation formula is as follows:

[0063]

[0064] Where, θ axis_new1 θ is the angle between the incident ray from channel 1 and the central axis. axis_new2 θ is the angle between the incident ray from channel 2 and the central axis. ro1 θ is the overall rotation angle of channel 1 within the meridional plane. ro2 It is the overall rotation angle of channel two within the meridional plane, θ 01 It is the grazing incidence angle of channel one, θ 02 It is the grazing incidence angle of channel two;

[0065] The thickness T of the ultra-smooth reflective substrate should be greater than 10 mm, and the spacing between channel one and channel two should satisfy the following relationship:

[0066] Sep 1,2 >T(5)

[0067] Based on the above four-channel, four-energy-point high-resolution X-ray microscopy optical structure, according to... Figure 1 The array of channels, from top to bottom, is named Channel 1, Channel 2, Channel 3, and Channel 4, with designed working energy points of 2.4 keV, 17.48 keV, 22.16 keV, and 8.05 keV, respectively, corresponding to grazing incidence angles of 2.0°, 0.65°, 0.35°, and 1.2°. The technical specifications of the four-channel microscope are summarized in Table 1. The system has a working object distance of 400 mm, a magnification of 20x, and a total object-image distance of 8400 mm.

[0068] Channels 1 and 4 are positioned on the outer side, away from the central axis, suitable for imaging diagnostics at large grazing incidence angles and low energy levels. Channels 2 and 3 are positioned on the inner side, closer to the central axis, suitable for imaging diagnostics at small grazing incidence angles and high energy levels. The corresponding image point positions for channels 1 to 4 are +30mm, +10mm, -10mm, and -30mm, respectively. The image point interval is 20mm, meeting the requirements of a segmented camera strip layout.

[0069] Figure 2-3 In this diagram, 1 is the object plane; 2 is the object point; 3 is the first reflecting mirror; 4 is the second reflecting mirror; 5 is the image plane; 6 is the image point; 7 is the perpendicular distance D_z of the image point; and 8 is the rotation angle θ of the mirror group in the meridional plane. ro ; 9 is the angle θ between the incident ray from the channel and the central axis. axis_new ; 10 is the perpendicular distance B_z of the first reflecting mirror; 11 is the grazing incidence angle θ0.

[0070] Taking Channel 1 and Channel 2 as examples, the rotation angles within the meridional plane are calculated as follows:

[0071]

[0072]

[0073] Furthermore, it can be deduced that the perpendicular distance of the first reflecting mirror in channel one is,

[0074]

[0075] The perpendicular distance of the first reflecting mirror in channel two is,

[0076]

[0077] Furthermore, the interval between channel one and channel two can be obtained, which meets the requirement of a 10mm thickness for the reflector substrate.

[0078] Sep 1,2 =B_z1-B_z2=(θ) axis_new1 -θ axis_new2 u = 36.0 mm

[0079] Therefore, it can be proven that the technical solutions for Channel 1 and Channel 2 are reasonable and feasible.

[0080] With no spatial interference, the same method can be used to prove that the technical solutions for Channel 3 and Channel 4 are reasonable and feasible.

[0081] Table 1 Technical Specifications of the Four-Channel Microscope

[0082]

[0083] For each imaging channel, a combination of hyperboloid and ellipsoidal mirrors is used to achieve large field-of-view, high-resolution imaging. The structural parameters of the mirrors are summarized in Table 2.

[0084] Table 2 Structural parameters of the reflector

[0085]

[0086]

[0087] Computer modeling was used to verify the system's configuration and evaluate its resolution using ray tracing. The RMS value of the speckle diffusion radius was used as the standard for resolution evaluation (already converted to the object space). Specifically, channel 1 achieved a spatial resolution better than 0.32 μm within a ±0.5 mm field of view; channel 2 achieved a spatial resolution better than 0.79 μm within the same range; channel 3 achieved a spatial resolution better than 1.35 μm; and channel 4 achieved a spatial resolution better than 0.47 μm within the same range. All channels achieved a resolution better than 3 μm, significantly exceeding the level of existing diagnostic technologies.

[0088] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A four-channel, four-energy-point high-resolution X-ray microscopy imaging optical structure, characterized by: It includes an object plane, four sets of reflecting mirrors, and an image plane. Each set of reflecting mirrors consists of two mirrors, namely a first reflecting mirror and a second reflecting mirror. The first reflecting mirror is closer to the object plane, and the second reflecting mirror is closer to the image plane. Each set of reflecting mirrors corresponds to an imaging channel. The horizontal line between the object plane and the image plane is the central axis. The four imaging channels are arranged opposite each other on both sides of the central axis. Each imaging channel forms an image point on the image plane, and there is an object point on the object plane. All four imaging channels adopt a double-mirror structure with two reflections. The double-mirror structure of each imaging channel can rotate around the object point to adjust the position of the image point on the image plane.

2. The four-channel, four-energy-point high-resolution X-ray microscopy optical structure according to claim 1, characterized in that: Two of the four imaging channels, which are closer to the central axis, use a smaller grazing incidence angle and correspond to the high-energy imaging channels; the two channels, which are farther from the central axis, use a larger grazing incidence angle and correspond to the low-energy imaging channels; the difference in grazing incidence angle between the high-energy imaging channels and the low-energy imaging channels is greater than 1°.

3. The four-channel, four-energy-point high-resolution X-ray microscopy optical structure according to claim 2, characterized in that: All four imaging channels employ a dual-mirror structure with two reflections; the dual-mirror structure of each imaging channel can rotate as a whole around the object point, thereby adjusting the position of the image point on the image plane.

4. The four-channel, four-energy-point high-resolution X-ray microscopy optical structure according to claim 3, characterized in that: The steps for adjusting the image point position of the grazing incidence dual-mirror structure in the imaging channel are as follows: S1: Design the vertical axis offset D_z of the image point; S2: Rotate the double-mirror structure around the object point. Calculate the overall rotation angle θ of the double-mirror structure. ro ; S3: Calculate the angle θ between the incident ray and the central axis. axis_new ; S4: Calculate the imaging channel mirror spacing Sep; S5: Determine whether the spacing between the reflectors meets the thickness requirements of the reflector substrate; If the conditions are met, the design of that channel is completed, and the design of the next channel begins; if not, the pixel layout of that channel is readjusted, and the process is repeated iteratively until the conditions are met.

5. The four-channel, four-energy-point high-resolution X-ray microscopy optical structure according to claim 4, characterized in that: The overall rotation angle θ of the dual-mirror structure of the imaging channel ro The calculation formula is: ， (1) Where D_z is the perpendicular distance of the image point in the image plane, and s is the sum of the object and image distances of the optical system; The angle θ between the incident ray and the central axis of the rotating imaging channel axis_new The calculation formula is: ， (2) Where, θ axis_org It is the angle between the incident ray and the central axis in the initial state, M is the channel magnification, and θ0 is the grazing incident angle of the mirror; The formula for calculating the perpendicular distance from the first reflecting mirror to the central axis in a double-mirror structure is as follows: ， (3) Where u is the distance from the object point to the center of the first reflecting mirror; Calculate the imaging channel mirror spacing Sep to meet the mirror substrate thickness requirements. The calculation formula is as follows: ， (4) Where, θ axis_new1 θ is the angle between the incident ray from channel one and the central axis. axis_new2 θ is the angle between the incident ray from channel two and the central axis. ro1 θ is the overall rotation angle of channel 1 within the meridional plane. ro2 It is the overall rotation angle of channel two within the meridional plane, θ 01 It is the grazing incidence angle of channel one, θ 02 It is the grazing incidence angle of channel two; The thickness T of the ultra-smooth reflective substrate and the spacing between channel one and channel two should satisfy the following relationship: (5)。

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