Lobster eye type X-ray microporous optical device with high-reflectivity double-layer film and preparation method

Abstract

The invention provides a lobster eye type X-ray microporous optical device with a high-reflectivity double-layer film and a preparation method. The lobster eye type X-ray microporous optical device with the high-reflectivity double-layer film comprises a glass-based micro-channel capillary array substrate, an X-ray micro-channel array substrate and an X-ray micro-channel array Plating a metal Ir film on the surface of the micro-channel; the absorbing layer thin film is plated on the surface of the metal Ir thin film, the absorbing layer thin film and the metal Ir thin film form a continuous film layer and do not react with each other, and film layer interface mutual diffusion is smaller than 2nm. Through the design of the invention, the effective area and consistency of the MPO optical device can be further improved, the problem of the absorption edge of the Ir metal reflecting film of the existing lobster eye type X-ray microporous optical device is solved, and the performance of the lobster eye type X-ray optical system is improved.

Description

Technical Field

[0001] The present invention relates to the field of X-ray imaging detection technology, in particular to a lobster-eye type X-ray micro-hole optical device, and more specifically to a lobster-eye type X-ray micro-hole optical device with a high reflectivity double-layer film and a preparation method thereof. Background Art

[0002] Thanks to the progress of X-ray astronomical optical technology, X-ray wide-field time-domain surveys to monitor massive targets and transient sources have attracted more and more attention from astronomers. Although the Wolter-type X-ray optical system has advantages such as good resolution and sensitivity, the observation field of view is very limited, usually less than 1°, and the size and weight of the mirror are quite considerable, which makes it difficult to meet the scientific needs of future X-ray wide-field monitoring. As a new type of X-ray bionic imaging system, the lobster-eye X-ray micro-aperture optical device (MPO) has a unique solid angle focusing capability and the best effective area-to-weight ratio. With its special microstructure orthogonal structure, the field of view can reach 4π spatial angles, which is unattainable by other grazing-incidence X-ray optical systems. Therefore, the lobster-eye X-ray optical system has been selected as the first choice for future X-ray wide-field astronomical telescopes, and is expected to truly expand the field of view beyond the Milky Way.

[0003] For X-ray focusing telescopes, due to the existence of the critical angle of grazing incidence of X-rays, the theoretical upper limit of the effective area of ​​X-rays is determined by the focal length. Therefore, how to obtain a wide-field lobster-eye X-ray focusing telescope with a large effective area and high sensitivity is a hot issue and development goal in X-ray astronomical optics research. X-ray double-layer film technology is one of the key technologies for high X-ray reflectivity. It can improve the X-ray reflectivity and effective area in a wider energy range under the condition of grazing incidence angles that meet the Bragg condition. However, the lobster-eye MPO optical device is a new type of X-ray micro-hole focusing device with millions of micro-channel arrays. During the period of engineering application in the field of space astronomical detection at home and abroad, the related lobster-eye X-ray high reflectivity technology is still in the exploratory stage. So far, there has been no application of X-ray double-layer film technology in lobster-eye X-ray optical systems.

[0004] Limited by the maturity of MPO optical technology and limited experimental resources at this stage, the application research of lobster-eye X-ray double-layer film optical devices is still in a blank stage internationally. At present, MPO optical devices have developed a single-layer metal film preparation technology based on atomic layer deposition technology (ALD), but have not fully utilized the advantages of MPO optical technology. When the focal length of a single MPO optical device is 375mm, the effective area of ​​the core technical indicator is not as good as the extreme (~2.5cm2@1keV). The Ir metal film has a good reflectivity above 2keV, but the absorption edge near 2keV has a certain impact on the observation performance of the wide-field X-ray telescope, such as Figure 1As shown in the figure, this is because when analyzing astronomical sources in the X-ray band, it is necessary to fit the flux and spectrum. The flux can evaluate the efficiency of the energy generation process of the source, and the spectrum can distinguish different radiation mechanisms. Due to the existence of the absorption edge near 2keV, the effective area curve drops too fast, resulting in low accuracy and large errors in fitting the X-ray energy spectrum curve near 2keV. It is difficult to obtain reliable and accurate scientific conclusions based on these observations to infer and calculate the physical processes involved. Summary of the invention

[0005] In view of the defects and shortcomings of the prior art, the purpose of the present invention is to propose a lobster-eye X-ray micropore optical device with a high reflectivity double-layer membrane, to develop X-ray double-layer membrane technology based on the existing ALD-Ir, to solve the bottleneck problems of the current MPO optical device single-layer Ir film, such as absorption edge, low X-ray reflectivity, small effective area and long observation time, so as to improve the effective area and detection sensitivity of the wide-field lobster-eye X-ray telescope.

[0006] According to a first aspect of the present invention, a lobster-eye type X-ray micro-aperture optical device with a high reflectivity double-layer film is provided, comprising:

[0007] A glass-based microchannel capillary array substrate;

[0008] A metal Ir film deposited on the surface of the microchannel; and

[0009] The absorption layer film is plated on the surface of the metal Ir film, the absorption layer film and the metal Ir film form a continuous film layer without mutual reaction, and the mutual diffusion of the film layer interface is less than 2nm.

[0010] According to a second aspect of the present invention, a method for preparing a lobster-eye type X-ray micro-hole optical device with a high reflectivity double-layer film is provided, comprising the following steps:

[0011] (1) Plating metal Ir film

[0012] 1) Ir(acac)3 is carried by N2 into the reaction chamber of the ALD deposition equipment and chemically adsorbed on the surface of the microchannel; then, the remaining Ir(acac)3 in the reaction chamber is washed and removed with N2;

[0013] 2) High-purity O2 enters the reaction chamber under vapor pressure and reacts with Ir(acac)3 adsorbed on the surface of the microchannel to generate Ir and byproducts H2O and CO2, forming an Ir layer of a certain thickness;

[0014] 3) Cyclic ALD saturation reaction, preparing a metal Ir film through a preset number of cycles, wherein the reaction chamber is cleaned with high-purity O2 between each cyclic ALD saturation reaction;

[0015] (2) Plating of absorption layer film

[0016] A low atomic coefficient material is used as a precursor, and an absorption layer film is obtained through LAD deposition cycles of a preset number of times. The low atomic coefficient material is one of Al2O3, BN, B4C or Si3N4.

[0017] As an optional embodiment, in each cycle of step (1), the time for cleaning the reaction chamber with high-purity O2 is between 20s and 60s, and the time for each cycle of ALD saturation reaction is controlled to be between 40s and 60s;

[0018] The number of cycles is set to be more than 200 times to obtain a metal Ir film with a thickness between 5 and 30 nm.

[0019] As an optional embodiment, in the step (2), the low atomic coefficient material used is Al2O3, and the precursors used for ALD cyclic deposition are TMA and water. The Al2O3 film layer is prepared as the absorption layer thin film through a preset number of cyclic depositions of TMA pulse-nitrogen purge-water pulse-nitrogen purge.

[0020] It should be understood that all combinations of the aforementioned concepts and the additional concepts described in more detail below can be considered as part of the inventive subject matter of the present disclosure as long as such concepts are not mutually inconsistent. In addition, all combinations of the claimed subject matter are considered as part of the inventive subject matter of the present disclosure.

[0021] The foregoing and other aspects, embodiments and features of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will be apparent from the following description or learned from the practice of the specific embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in each figure may be represented by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings.

[0023] Figure 1 It is a schematic diagram of reflectivity simulation of an X-ray micro-hole optical element using a single-layer Ir reflective film in the prior art.

[0024] Figure 2 Schematic diagram of the microstructure of a lobster-eye microporous optical element (MPO) and a microchannel according to an embodiment of the present invention.

[0025] Figure 3 This is a measured diagram of the inner wall roughness of a lobster-eye microporous optical element (MPO) after microchannel coating according to an embodiment of the present invention.

[0026] Figure 4 1 is a schematic diagram of reflectivity simulation based on a high-reflectivity double-layer film lobster-eye microporous optical element (MPO) according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0028] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed by the present invention are not limited to any implementation. In addition, some aspects disclosed by the present invention can be used alone or in any appropriate combination with other aspects disclosed by the present invention.

[0029] {Example 1}

[0030] In view of the fact that the absorption edge of the single-layer metal Ir film of the existing lobster-eye type X-ray micro-hole optical device near 2keV causes the effective area curve to drop too fast, resulting in the technical problem that the X-ray energy spectrum curve fitting accuracy near 2keV is not high and the error is large, according to an embodiment of the present invention, a lobster-eye type X-ray micro-hole optical device with a high reflectivity double-layer film is designed, including:

[0031] A glass-based microchannel capillary array substrate;

[0032] A metal Ir film deposited on the surface of the microchannel; and

[0033] The absorption layer film is plated on the surface of the metal Ir film, the absorption layer film and the metal Ir film form a continuous film layer without mutual reaction, and the mutual diffusion of the film layer interface is less than 2nm.

[0034] The embodiments of the present invention propose a double-layer film technology for lobster-eye X-ray microporous optical elements based on a single-layer ALD-Ir, thereby solving bottleneck problems such as absorption edge, low X-ray reflectivity, small effective area and long observation time of single-layer Ir films in current MPO optical devices, and can significantly improve the effective area and detection sensitivity of wide-field lobster-eye X-ray telescopes, especially solving the absorption edge problem near 2keV.

[0035] As an optional embodiment, the microchannel capillary array substrate has 100,000 to 2 million microchannels, each microchannel is a square microchannel with a side length of 10μm to 40μm, a wall thickness of 1μm to 8μm, a thickness of 0.5mm to 5mm, an aspect ratio of 10 to 200, and a curvature radius of 100mm to 3000mm.

[0036] It should be understood that the length of a single microchannel capillary array substrate is usually between 30 mm and 80 mm.

[0037] As an optional implementation, the absorption layer film is plated with a low atomic coefficient material, and the low atomic coefficient material includes one of Al2O3, BN, B4C or Si3N4.

[0038] As an optional implementation, the thickness of the metal Ir film is 5 to 30 nm.

[0039] As an optional implementation, the thickness of the absorption layer film is 5 to 30 nm.

[0040] As an optional implementation, the surface roughness of the double-layer film composed of the metal Ir film and the absorption layer film is better than 1 nm.

[0041] In an embodiment of the present invention, the microchannel capillary array substrate adopts the microchannel plate array preparation technology, and its device is made of lead glass. On this basis, the present invention proposes to use atomic layer deposition technology to prepare a double-layer film, wherein a metal Ir film is first deposited on the surface of the microchannel, and then a low atomic coefficient film is deposited, wherein the thickness of the metal Ir film is set to 5 to 30 nm, and the thickness of the low atomic coefficient material film is set to 5 to 30 nm. Thus, the effective area and consistency of the MPO optical device are further improved, the absorption edge problem of the Ir metal reflective film of the existing lobster eye type X-ray microporous optical device is solved, and the performance of the lobster eye type X-ray optical system is improved.

[0042] It should be understood that the lobster-eye type X-ray micro-aperture optical device with a high reflectivity double-layer film proposed in the present invention can be used as an X-ray focusing lens in a wide-field X-ray telescope.

[0043] {Example 2}

[0044] According to an embodiment of the present invention, a method for preparing a lobster-eye type X-ray micro-hole optical device with a high reflectivity double-layer film is also provided, comprising the following steps:

[0045] (1) Plating metal Ir film

[0046] 1) Ir(acac)3 is carried by N2 into the reaction chamber of the ALD deposition equipment and chemically adsorbed on the surface of the microchannel; then, the remaining Ir(acac)3 in the reaction chamber is washed and removed with N2;

[0047] 2) High-purity O2 enters the reaction chamber under vapor pressure and reacts with Ir(acac)3 adsorbed on the surface of the microchannel to generate Ir and byproducts H2O and CO2, forming an Ir layer of a certain thickness;

[0048] 3) Cyclic ALD saturation reaction, preparing a metal Ir film through a preset number of cycles, wherein the reaction chamber is cleaned with high-purity O2 between each cyclic ALD saturation reaction;

[0049] (2) Plating of absorption layer film

[0050] A low atomic coefficient material is used as a precursor, and an absorption layer film is obtained through LAD deposition cycles of a preset number of times. The low atomic coefficient material is one of Al2O3, BN, B4C or Si3N4.

[0051] In each cycle of step (1), the time for cleaning the reaction chamber with high-purity O2 is between 20s and 60s, and the time for each cycle of ALD saturation reaction is controlled between 40s and 60s;

[0052] The number of cycles is set to be more than 200 times to obtain a metal Ir film with a thickness between 5 and 30 nm.

[0053] Among them, in step (2), the low atomic coefficient material used is Al2O3, and the precursors used for ALD cyclic deposition are TMA and water. Through a preset number of cyclic depositions of TMA pulse-nitrogen purge-water pulse-nitrogen purge, an Al2O3 film layer is prepared as an absorption layer thin film.

[0054] {Example 3}

[0055] In this embodiment, we take a double-layer film system consisting of a metal Ir film and an Al2O3 absorption layer film on the metal Ir film as an example to further illustrate the implementation of the present invention.

[0056] Take the lobster-eye X-ray microaperture optical device used in a wide-field X-ray telescope as an example. Figure 2 As shown, the size of a single device is 42.5mm×42.5mm, the side length of the square microchannel is 40μm, the wall thickness is 8μm, the thickness is 2.5mm, the aspect ratio is 62.5, the radius of curvature is 750mm, and each device has approximately 800,000 microchannels.

[0057] The thickness of the metal Ir film used as the bottom layer is designed to be 20nm, and the thickness of the Al2O3 film used as the absorption layer is designed to be 10nm.

[0058] 1. Plating of metal Ir thin film

[0059] ALD-Ir consists of two half reactions. The metal Ir film is prepared in an ALD deposition device (such as Beneq TFS-200), which specifically includes:

[0060] 1) Ir(acac)3 is carried by N2 into the reaction chamber of the ALD deposition equipment and chemically adsorbed on the surface of the microchannel; then, the remaining Ir(acac)3 in the reaction chamber is washed and removed with N2;

[0061] 2) High-purity O2 enters the reaction chamber under vapor pressure and reacts with Ir(acac)3 adsorbed on the surface of the microchannel to generate Ir and byproducts H2O and CO2, forming an Ir layer of a certain thickness;

[0062] 3) Cyclic ALD saturation reaction, preparing a metal Ir film through a preset number of cycles, wherein high-purity O2 is used to clean the reaction chamber between each cyclic ALD saturation reaction.

[0063] The flow rate of high-purity N2 was set to 500 sccm, and the number of saturated reaction deposition cycles on the inner surface of the lead glass microchannel was 1200 times to obtain a 20nm Ir film. In each cycle, the time for cleaning the reaction chamber with high-purity O2 was between 20s and 60s, and the time for each cycle of ALD saturated reaction was controlled at 40s to 60s.

[0064] The pressure of the vacuum chamber and reaction chamber of the ALD deposition equipment is controlled at 1×10 3 Pa and 3×10 3 Pa. As a solid precursor, Ir(acac)3 is placed in a heated flask and added through a heat source. It is heated to about 175°C and then evaporated. After repeated experiments, it was found that the film deposited at 330°C-350°C has better stability and thickness consistency.

[0065] Preferably, the precursor pulse time of Ir(acac)3 is 3-5s.

[0066] 2. Plating of Al2O3 absorption layer film

[0067] The precursors used for depositing the Al2O3 film layer by ALD-Al2O3 are trimethylaluminium (TMA) and water (H2O), and the deposition temperature is set to 210°C. After 100-120 cycles, a 10nm Al2O3 film is obtained.

[0068] As an optional embodiment, the Al2O3 film layer is deposited by a cycle of TMA pulse-nitrogen purge-water pulse-nitrogen purge.

[0069] It should be understood that the deposition of the aforementioned Al2O3 absorption layer film and metal Ir film can be based on the ALD deposition equipment and the corresponding deposition process can be designed according to the required thickness to complete a stable film preparation process.

[0070] After the preparation of the double-layer film, the film thickness, roughness and optical properties of the double-layer film were tested. Figure 3 As shown, the measured result of the inner wall roughness is 0.78nm.

[0071] A physical simulation model was constructed based on the measured results of the prepared samples. Figure 4 From the simulation results of the lobster-eye type X-ray micro-hole optical device shown, it can be seen that compared with the single-layer film of metal Ir used in the prior art, the double-layer film technology proposed in the present invention significantly improves the characteristic peak near the absorption edge 2keV, and the reflectivity of the overall X-ray band is significantly improved.

[0072] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A lobster-eye X-ray micro-aperture optical device with a high reflectivity double-layer film, characterized in that: include: A glass-based microchannel capillary array substrate; Metal Ir film coated on the surface of microchannel; as well as The absorption layer film is plated on the surface of the metal Ir film, the absorption layer film and the metal Ir film form a continuous film layer without mutual reaction, and the mutual diffusion of the film layer interface is less than 2nm.

2. The high reflectivity double-layer film lobster-eye X-ray micro-aperture optical device according to claim 1, characterized in that: The microchannel capillary array substrate has 100,000 to 2 million microchannels, each of which is a square microchannel with a side length of 10 μm to 40 μm, a wall thickness of 1 μm to 8 μm, a thickness of 0.5 mm to 5 mm, an aspect ratio of 10 to 200, and a curvature radius of 100 mm to 3000 mm.

3. The high reflectivity double-layer film lobster-eye X-ray micro-aperture optical device according to claim 1, characterized in that: The absorption layer film is plated with a low atomic coefficient material, and the low atomic coefficient material includes one of Al2O3, BN, B4C or Si3N4.

4. The high reflectivity double-layer film lobster-eye X-ray micro-aperture optical device according to claim 1, characterized in that: The thickness of the metal Ir film is 5-30 nm.

5. The high reflectivity double-layer film lobster-eye X-ray micro-aperture optical device according to claim 1, characterized in that: The thickness of the absorption layer film is 5-30 nm.

6. The high reflectivity double-layer film lobster-eye X-ray micro-aperture optical device according to claim 1, characterized in that: The surface roughness of the double-layer film composed of the metal Ir film and the absorption layer film is better than 1 nm.

7. A lobster-eye type X-ray microporous optical device with a high reflectivity double-layer film according to any one of claims 1 to 6 The method for preparing a device is characterized in that: The following steps are involved: (1) Plating metal Ir film 1) Ir(acac)3 is carried by N2 into the reaction chamber of the ALD deposition equipment and chemically adsorbed on the surface of the microchannel; then, the remaining Ir(acac)3 in the reaction chamber is washed and removed with N2; 2) High-purity O2 enters the reaction chamber under vapor pressure and reacts with Ir(acac)3 adsorbed on the surface of the microchannel to generate Ir and byproducts H2O and CO2, forming an Ir layer of a certain thickness; 3) Cyclic ALD saturation reaction, preparing a metal Ir film through a preset number of cycles, wherein the reaction chamber is cleaned with high-purity O2 between each cyclic ALD saturation reaction; (2) Plating of absorption layer film A low atomic coefficient material is used as a precursor, and an absorption layer film is obtained through LAD deposition cycles of a preset number of times. The low atomic coefficient material is one of Al2O3, BN, B4C or Si3N4.

8. The preparation method according to claim 7, characterized in that: In each cycle of step (1), the time for cleaning the reaction chamber with high-purity O2 is between 20s and 60s, and the time for each cycle of ALD saturation reaction is controlled between 40s and 60s; The number of cycles is set to be more than 200 times to obtain a metal Ir film with a thickness between 5 and 30 nm.

9. The preparation method according to claim 8, characterized in that: In the step (2), the low atomic coefficient material used is Al2O3, and the precursors used for ALD cyclic deposition are TMA and water. The Al2O3 film is prepared as the absorption layer film through a preset number of cyclic depositions of TMA pulse-nitrogen purge-water pulse-nitrogen purge.

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