Methods to improve the internal structure of microchannel plate X-ray collimators

Abstract

This invention provides a method for improving the internal structure of a microchannel plate X-ray collimator. During the single-wire bar arrangement process of the microchannel plate X-ray collimator, filler wires are inserted into the gaps between adjacent single wires. The single wires and filler wires are arranged in a tightly interlaced manner to form a regular hexagonal collimator multifilament bar, with both single wires and filler wires having diameters on the order of millimeters. The outer filler wires of the multifilament bar are thickened so that the edges of the outer filler wires are on the same horizontal plane as the edges of the single wires in the bar. This invention's method for improving the internal structure of a microchannel plate X-ray collimator reduces the extrusion deformation error introduced during the fusion compression imaging process by designing optimal boundary filler wire dimensions, thereby improving the array imaging accuracy.

Description

Technical Field

[0001] This invention relates to the field of microchannel plate technology, and more specifically to a method for improving the internal structure of a microchannel plate-type X-ray collimator. Background Technology

[0002] The Enhanced X-ray Timing and Polarization Probe (eXTP) is a major international collaborative scientific project initiated and led by Chinese scientists. The collaboration comprises over 100 research institutions from more than 20 countries, regions, and organizations, including China, Italy, Germany, Spain, the United Kingdom, France, the Netherlands, and Switzerland. eXTP's scientific objective is to detect and develop fundamental physical laws of the universe under extreme gravitational, magnetic, and density conditions by observing the X-ray radiation from black holes, neutron stars, and quark stars. This can be summarized as: "One wonder (black holes), two stars (neutron stars and quark stars), and three extremes (extreme gravity, magnetic fields, and densities)."

[0003] The eXTP satellite possesses four payloads: a Large Area X-ray Collimator (LAD), a Spectrometer X-ray Focusing Telescope Array (SFA), a Polarimeter X-ray Focusing Telescope Array (PFA), and a Wide-Angle Monitor (WFM). The Large Area X-ray Collimator (LAD) payload, a crucial component of the eXTP telescope, primarily operates in the 2–30 keV energy range for photon observation (extending to approximately 80 keV for out-of-field bursts). The LAD payload includes a large-area SDD spectrometer detector and a microchannel plate X-ray collimator.

[0004] Microchannel plate X-ray collimators, as optical devices for laser-guided array (LAD) payloads, are novel micro-aperture collimating devices developed based on microchannel plate manufacturing technology used in the night vision military field. The internal array structure of the microchannel plate X-ray collimator determines the effective area and field of view of the LAD payload, and is a core parameter of the LAD payload. The internal array structure of the X-ray collimator is mainly formed by high-temperature fiber drawing. Traditional methods improve the internal structure of the microaperture by increasing the dimensional accuracy of the fiber and reducing the boundary extrusion process errors introduced during high-temperature melting and pressing. However, the above methods do not address the design of the multifilament unit structure. Summary of the Invention

[0005] The purpose of this invention is to provide a method for improving the internal structure of a microchannel plate X-ray collimator. By designing the optimal boundary filler wire size, the extrusion deformation error introduced by the fusion imaging process is reduced, thereby improving the array imaging accuracy.

[0006] According to a first aspect of the present invention, a method for improving the internal structure of a microchannel plate-type X-ray collimator is provided, comprising:

[0007] In the process of preparing a single-wire bar for a microchannel plate-type X-ray collimator, filler wires are filled into the pores between adjacent single wires, and the single wires and filler wires are arranged in a tightly interlaced manner to form a regular hexagonal multi-wire bar.

[0008] The filling positions are divided into internal and external. The filling position located on the outermost side of the cross-section of the multifilament bar is defined as external, and the remaining filling positions of the multifilament bar are defined as internal.

[0009] In particular, the filler wires at the outer filling position of the multifilament rod are thickened filler wires, which are used as outer filler wires. Their outer diameter is larger than that of the filler wires at the inner filling position, so that the edge of the outer filler wire is on the same horizontal plane as the edge of the single wire of the bar.

[0010] As an optional embodiment, in the process of arranging monofilaments, the filling wire at the internal filling position is defined as the internal filling wire, and the outer diameter of the outer filling wire is 1.2 to 2 times the outer diameter of the monofilament of the internal filling wire.

[0011] As an optional embodiment, the outer diameter D of the outer filler wire and the outer diameter d of the inner filler wire satisfy the following:

[0012] D≈1.7×d.

[0013] As an optional embodiment, the geometric relationship between the diameter d of the internal filling filament and the diameter R of the monofilament is as follows:

[0014]

[0015] As an optional embodiment, the diameters of both the monofilament and the filler filament are in the millimeter range.

[0016] As an optional embodiment, in the fabrication process of the microchannel plate-type X-ray collimator, the diameter of the single filament used is 2.5±0.1mm, the outer diameter of the inner filling filament is 0.38±0.03mm, and the size of the outer filling filament is 0.64±0.03mm, so that the collimator is densely filled.

[0017] As an optional embodiment, the outer filler wire and the inner filler wire are drawn from the same glass material, and are made of the same glass material as the skin glass used in the microchannel plate X-ray collimator.

[0018] As an optional embodiment, the peripheral filler wire, the internal filler wire, and the collimator skin glass are all made of the same high-Pb glass material.

[0019] As an optional embodiment, the composition and proportion of the high-Pb glass material are as follows:

[0020] PbO - 49.4%;

[0021] K2O -7.6%;

[0022] SiO2 - 27.4%;

[0023] Na₂O - 4.55%;

[0024] Bi2O3-11%;

[0025] BaO 0.05%.

[0026] Therefore, in the method for improving the internal structure of a microchannel plate X-ray collimator proposed in this invention, during the single-wire bar arrangement process of the microchannel plate X-ray collimator, filler wires are filled into the gaps between adjacent single wires. The single wires and filler wires are arranged in a tightly interlaced manner to form a regular hexagonal collimator multifilament bar. By thickening the outer filler wires of the multifilament bar, the edges of the outer filler wires are made to be on the same horizontal plane as the edges of the single wires in the bar arrangement. Then, it can be fixed and shaped using a bar arrangement mold, and subsequent screen segment melting and pressing processes are performed to reduce the extrusion deformation error introduced by the melting and pressing imaging process, thereby improving the array imaging accuracy.

[0027] The fabrication process of the microchannel plate X-ray collimator of the present invention is similar to that of conventional microchannel plates, including processes such as tube / rod melting, single-wire drawing, single-wire arraying, multi-wire drawing, multi-wire arraying, screen segment melting and pressing, cold working, and chemical etching to form a micropore array. It should be understood that the method of the present invention mainly relates to the single-wire arraying stage of the fabrication process of the microchannel plate X-ray collimator.

[0028] Preferably, the outer filler wire and the inner filler wire are drawn from the same glass material. For example, the filler wire and the collimator skin glass are made of the same material, which is a high-lead material, to ensure that the filler wires are densely packed while maintaining the collimator's collimation performance for X-rays.

[0029] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below may be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other. Furthermore, all combinations of the claimed subject matter are considered part of the inventive subject matter of this disclosure.

[0030] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0031] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings.

[0032] Figure 1 A schematic diagram of the multifilament rod before the outer filler wires are thickened.

[0033] Figure 2 This is a schematic diagram of the multifilament rod with thickened outer filler wire proposed in this invention.

[0034] Figure 3 Flowchart of the fabrication process for a microchannel plate X-ray collimator.

[0035] Figure 4 A schematic diagram of the collimator before the outer filler wire is thickened.

[0036] Figure 5 A schematic diagram of microscope observation after thickening the outer filler wire.

[0037] Figure 6 A schematic diagram of the collimator before the outer filler wire is thickened.

[0038] Figure 7 A schematic diagram of X-ray imaging of the collimator after the outer filler wires have been thickened.

[0039] Meaning of the reference numerals in the diagram:

[0040] 1-Monofilament; 2-Internal filler filament; 3-Outer filler filament. Detailed Implementation

[0041] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0042] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, which illustrate numerous illustrative embodiments. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed herein are not limited to any particular implementation. Furthermore, some aspects of the invention disclosed may be used alone or in any suitable combination with other aspects of the invention disclosed.

[0043] Combination Figure 2-7The example shown is for a microchannel plate X-ray collimator. Its fabrication process mainly includes tube / rod melting preparation (shell glass tube and core glass tube), single-wire drawing, single-wire bar stacking, multi-wire drawing, multi-wire screen stacking, screen segment melting and pressing, cold working, and chemical etching to form a micropore array. This is similar to conventional microchannel plate processes. Figure 3 As shown. The method of this invention mainly relates to the single-wire bar stage in the fabrication process of a microchannel plate X-ray collimator.

[0044] As shown in the example, the collimator multifilament bar includes a hexagonal structure composed of dozens of monofilaments and filler wires located between adjacent monofilaments. The diameter of both the monofilaments and filler wires is on the order of millimeters. The monofilaments and filler wires are arranged in a close interlaced manner to form the collimator multifilament bar.

[0045] like Figure 1 , 2 These are schematic diagrams of the multifilament rod before and after the outer filler wires are thickened. The multifilament rod of the X-ray collimator is composed of millimeter-sized monofilaments and filler wires arranged in a tightly interlaced pattern. Figure 1 The image shows the outer filler wire thickened before the multifilament rod is made, that is, using ordinary filler wire of the same size as the inner filler wire, and the size of the outer filler wire is the same as that of the inner filler wire. Figure 2 The image shows a multifilament rod with thickened outer filler filaments. The outer filler filament 3 is nearly twice the size of the inner filler filament 2, ensuring that the boundary of the outer filler filament 3 is aligned with the boundary of the outer monofilament 1. It can then be fixed and shaped using a bar die for subsequent processing, such as vacuum melting.

[0046] In an embodiment of the present invention, the filler wires at the outer filling position of the multifilament rod are thickened filler wires, which are used as the outer filler wires 2. The outer diameter of the single wire is larger than the outer diameter of the filler wires at the inner filling position, so that the edge of the outer filler wires 2 is on the same horizontal plane as the edge of the single wires 1 of the bar.

[0047] Among them, combined Figure 2 As shown, the filling wire at the internal filling position is defined as the internal filling wire 2, and the outer diameter of the outer filling wire 3 is 1.2 to 2 times the outer diameter of the internal filling wire 2.

[0048] Among them, the outer diameter D of the outer filling wire 2 and the outer diameter d of the inner filling wire 3 satisfy:

[0049] D≈1.7×d.

[0050] Referring to the diagram, the geometric relationship between the diameter d of the internal filling filament 3 and the diameter R of the monofilament 1 is as follows:

[0051]

[0052] As an optional embodiment, the X-ray collimator filler wire can be prepared by high-temperature drawing. Unlike the drawing of single wires into tubes, the filler wire can be drawn from a single glass material.

[0053] Preferably, the outer filler wire, the inner filler wire, and the glass covering the monofilament are all made of the same material, namely high-lead glass. This is to ensure that they can be smoothly fused together during the subsequent wire drawing and pressing process, and to maintain the high lead content of the X-ray collimator to guarantee its collimation performance for X-rays.

[0054] As an optional embodiment, the composition and proportion of the high-lead glass material are selected as follows:

[0055] PbO - 49.4%;

[0056] K2O -7.6%;

[0057] SiO2 - 27.4%;

[0058] Na₂O - 4.55%;

[0059] Bi2O3-11%;

[0060] BaO 0.05%.

[0061] Preferably, the bar stacking mold is made of plastic nylon material, which helps to reduce wear on the monofilaments and filler filaments during the stacking process; the mold ensures that the three sets of opposite sides of the multifilament bar are dimensionally accurate within ±0.02mm.

[0062] For example, taking a microchannel plate-type X-ray collimator with a single filament diameter of 2.5±0.1mm as an example, since the single filament diameter of the microchannel plate-type X-ray collimator is large, the gap between the single filaments is large during the bar arrangement process, so filling is required; based on the single filament diameter, the size of the internal filling filament is calculated to be 0.38±0.03mm.

[0063] When a 0.35mm filler wire is used around the monofilament rod, insufficient filling occurs, resulting in insufficient tightness at the boundary of the multifilament in the fabricated X-ray collimator. Therefore, in the embodiments of the present invention, the size of the outer filler wire is thickened.

[0064] Based on the above examples and the size of the gap around the monofilament rod, the size of the outer filler wire is calculated to be 0.64±0.03mm, which can make the collimator densely filled.

[0065] Preferably, the arranged multifilaments are drawn to a thickness of 0.9mm ± 0.03mm, and the screen segments are arranged into regular hexagonal segments with opposite sides of 138mm using a screen arrangement mold.

[0066] Preferably, the melt-pressed screen segment is cold-processed to have an external dimension of 111mm×72.5mm×5mm. The core material is removed by alternating acid and alkali etching to maintain the complete array structure.

[0067] Observation using a tool microscope, such as Figure 4 , 5 Microscopic observation diagrams before and after thickening the outer filler wires show that the size of the filler wires at the boundary of the multifilament rod is significantly larger than that of the inner filler wires after thickening, resulting in a significantly enhanced filling effect, less deformation of the boundary microstructure, and less high-temperature extrusion error during melt pressing. Figure 4 , 5 In comparison, thickening the filler wire at the boundary of the multifilament significantly improved the internal structure of the X-ray collimator.

[0068] Limited by conventional optical observation methods and the size of microchannels, X-ray imaging technology is commonly used internationally to evaluate the internal structure of microchannel plates. The quality of the pointing accuracy characterizes the quality of the microstructure array, such as... Figure 6 , 7 The X-ray imaging results before and after thickening the outer filler wire are shown. After the improvement, the X-ray point spread function is closer to the theoretical circle, while the point spread before the improvement is severely distorted. The pointing accuracy at half maximum (FWHM) is improved from 8 minutes to 3 minutes, indicating that the internal structure has been significantly improved.

[0069] Thus, the X-ray collimator formed using the above-mentioned bar arrangement method can effectively improve internal structural problems.

[0070] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for improving the internal structure of a microchannel plate-type X-ray collimator, characterized in that, include: In the process of preparing a single-wire bar for a microchannel plate-type X-ray collimator, filler wires are filled into the pores between adjacent single wires, and the single wires and filler wires are arranged in a tightly interlaced manner to form a regular hexagonal multi-wire bar. The filling positions are divided into internal and external. The filling position located on the outermost side of the cross-section of the multifilament bar is defined as external, and the remaining filling positions of the multifilament bar are defined as internal. Among them, the filler wires at the outer filling position of the multifilament rod are thickened filler wires as peripheral filler wires. The outer diameter of the peripheral filler wires is larger than the outer diameter of the filler wires at the inner filling position, so that the edge of the peripheral filler wires is on the same horizontal plane as the edge of the monofilament of the bar. The outer filler wire and the inner filler wire are drawn from the same glass material, and are made of the same glass material as the skin glass used in the microchannel plate X-ray collimator. In the fabrication process of the microchannel plate-type X-ray collimator, the diameter of the single filament used is 2.5±0.1mm, the outer diameter of the internal filling filament is 0.38±0.03mm, and the size of the outer filling filament is 0.64±0.03mm, so that the collimator is densely filled.

2. The method for improving the internal structure of a microchannel plate X-ray collimator according to claim 1, characterized in that, In the process of monofilament bar arrangement, the filling wire at the internal filling position is defined as the internal filling wire, and the outer diameter of the outer filling wire is 1.2 to 2 times the outer diameter of the internal filling wire.

3. The method for improving the internal structure of a microchannel plate X-ray collimator according to claim 1, characterized in that, The outer diameter D of the outer filler wire and the outer diameter d of the inner filler wire satisfy the following: D≈1.7d.

4. The method for improving the internal structure of a microchannel plate X-ray collimator according to claim 3, characterized in that, The geometric relationship between the diameter d of the internal filling filament and the diameter R of the single filament is as follows: .

5. The method for improving the internal structure of a microchannel plate X-ray collimator according to claim 1, characterized in that, Both the monofilament and the filler filament have diameters in the millimeter range.

6. The method for improving the internal structure of a microchannel plate X-ray collimator according to claim 1, characterized in that, The outer filler wire, the inner filler wire, and the skin glass are all made of the same high-Pb glass material.

7. The method for improving the internal structure of a microchannel plate X-ray collimator according to claim 6, characterized in that, The composition and proportion of the high-Pb glass material are as follows: PbO -49.4%; K2O -7.6%; SiO2 -27.4%; Na2O -4.55%; Bi2O3-11%; BaO 0.05%.

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