Micro-channel plate for improving spatial resolution

Abstract

The invention discloses a micro-channel plate for improving spatial resolution. The micro-channel plate comprises an input electrode, a multiplication channel and an output electrode, the input electrode is located at the input end of the multiplication channel, the output electrode is located at the output end of the multiplication channel, and the input electrode is a nickel-chromium electrode; the multiplication channel is made of lead-containing glass with secondary electron emission performance; and the output electrode is made of a material of which the maximum secondary electron emission coefficient is smaller than that of the nickel-chromium electrode. The spatial resolution of the microchannel plate can be greatly improved under the effects of reducing the maximum secondary electron emission coefficient of the output electrode and increasing the immersion depth of the output electrode.

Description

Technical Field

[0001] The present invention relates to the technical field of microchannel plates, in particular to a microchannel plate with improved spatial resolution. Background Art

[0002] The microchannel plate is a large-array electron multiplying detector with very high gain and time resolution. It is widely used in optoelectronic equipment such as night vision devices, electron microscopes, and particle detectors.

[0003] A microchannel plate (MCP) is a small glass disk coated with a metal film, consisting of countless channels (typically 2 to 6 million channels). Made of leaded glass with a high secondary electron emission coefficient, the MCP exhibits secondary electron emission properties, allowing each channel to function as an independent electron multiplier. When the MCP is operating, a voltage is applied across its terminals, creating an axial electric field within the channel. Electrons, charged particles, or photons collide with the inner wall of the MCP channel at specific energies and angles, generating secondary electrons. Driven by the electric field, these electrons accelerate along the channel toward the output end of the MCP, continuously striking the inner wall and generating more secondary electrons. Ultimately, a large number of electrons are emitted at the output end, thereby achieving electron multiplication and ultimately detecting and enhancing images or signals.

[0004] Spatial resolution is one of the key indicators for measuring the performance of a microchannel plate, which directly affects the clarity and details of the image. Hamamatsu Photonics Co., Ltd. in Japan proposed to improve the spatial resolution of the microchannel plate from the following two aspects: (1) shortening the distance between the microchannel plate and the phosphor screen; (2) increasing the acceleration voltage between the microchannel plate and the phosphor screen. However, the above methods do not start from the microchannel plate itself, and place higher requirements on the application scenarios of the microchannel plate. In addition, reducing the aperture of the microchannel plate is also a generally recognized method to improve spatial resolution, but it places higher requirements on the manufacturing process and the optimization effect is limited. Summary of the Invention

[0005] The purpose of the present invention is to provide a microchannel plate with improved spatial resolution. The spatial resolution of the microchannel plate is improved by selecting an output electrode material with a low secondary electron emission coefficient and deepening the immersion depth of the output electrode.

[0006] To achieve the above object, the technical solution provided by the present invention is:

[0007] A first aspect of the present application provides a microchannel plate for improving spatial resolution, comprising an input electrode, a multiplication channel, and an output electrode; the input electrode is located at the input end of the multiplication channel, and the output electrode is located at the output end of the multiplication channel, wherein:

[0008] The input electrode is a nickel-chromium electrode;

[0009] The multiplication channel is made of lead-containing glass with secondary electron emission performance;

[0010] The output electrode is made of a material having a maximum secondary electron emission coefficient smaller than that of the nickel-chromium electrode.

[0011] To optimize the above technical solutions, specific limitations also include:

[0012] The maximum secondary electron emission coefficient of the material of the output electrode does not exceed 1, and the smaller the better.

[0013] Under the premise that the gain allows, the deeper the output electrode is immersed in the multiplication channel, the better.

[0014] The diameter of the multiplication channel is 5 to 20 microns; the inclination angle of the multiplication channel is 5 to 15 degrees; and the maximum secondary electron emission coefficient of the multiplication channel is 2 to 5.

[0015] Furthermore, the depth of the input electrode immersed in the multiplication channel is 0.3 to 2 times the diameter of the multiplication channel, and the depth of the output electrode immersed in the multiplication channel is 1 to 3 times the diameter of the multiplication channel.

[0016] Furthermore, the voltage of the input electrode is 600-1200V lower than the voltage of the output electrode.

[0017] An anode is arranged behind the output electrode, the distance between the anode and the output electrode is 100 to 1000 microns, and the voltage of the anode is 100 to 500V higher than that of the output electrode.

[0018] A second aspect of the present application provides a method for improving the spatial resolution of a microchannel plate, comprising the following steps:

[0019] Fabricating a microchannel plate;

[0020] An input electrode is evaporated on the input surface of the microchannel plate, and an output electrode is evaporated on the output surface of the microchannel plate.

[0021] To optimize the above technical solutions, specific measures taken also include:

[0022] Furthermore, by controlling the positional relationship between the evaporation source and the microchannel plate, the depth of the input electrode and the output electrode immersed in the multiplication channel is controlled.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention optimizes and improves the microchannel plate by selecting an output electrode material with a low secondary electron emission coefficient and deepening the immersion depth of the output electrode, thereby achieving the purpose of improving spatial resolution without limiting the application scenario and manufacturing process.

[0025] The spatial dispersion of the multiplied electrons at the output end of the microchannel plate is caused by the dispersion of the multiplied electron emission angle. The present invention proposes to select a material with a secondary electron emission coefficient smaller than that of the nickel-chromium electrode and increase the immersion depth of the output electrode, thereby utilizing a low secondary electron emission coefficient material to eliminate the multiplied electrons with a larger emission angle. The deeper the immersion depth of the output electrode, the better the elimination effect, which can significantly improve the spatial resolution of the microchannel plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : Schematic diagram of the structure of a high spatial resolution microchannel plate provided by the present invention.

[0027] Figure 2 : Relationship between the peak half-maximum width of the output pulse position distribution in the X direction and the output electrode immersion depth and the output electrode maximum secondary electron emission coefficient in the embodiment of the present invention.

[0028] Figure 3 : Relationship between the peak half-width of the output pulse position distribution in the Y direction and the output electrode immersion depth and the output electrode maximum secondary electron emission coefficient in the embodiment of the present invention.

[0029] In the figure: 1. Input electrode; 2. Multiplication channel; 3. Output electrode; 4. Anode. DETAILED DESCRIPTION

[0030] The above contents of the present invention are further described in detail below in the form of specific implementation methods, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments. All technologies implemented based on the above contents of the present invention belong to the scope of the present invention.

[0031] The orientation or position relationship is based on the relationship shown in the drawings and is only for the convenience of describing the present invention and simplifying the description. It does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0032] The present invention provides a microchannel plate with improved spatial resolution and a method for preparing the same. Figure 1 As shown, it includes: an input electrode 1, a multiplication channel 2, and an output electrode 3. The input electrode 1 is located at the input end of the multiplication channel 2, and the output electrode 3 is located at the output end of the multiplication channel 2.

[0033] In some embodiments, the steps for making a microchannel plate include: making a glass tube-rod assembly; drawing single filaments in proportion, bundling multifilament rods, and drawing multifilament rods; arranging and melting and pressing to obtain blanks, and then performing cold processing such as slicing, rounding, and polishing; cleaning, and then chemically etching to melt the core glass; hydrogen reduction to form a secondary electron emission surface with a suitable surface resistivity on the inner wall of the channel; and finally plating electrodes.

[0034] In some embodiments, input electrode 1 is made of a conventional nickel-chromium electrode, deposited on the input surface of the microchannel plate. The immersion depth of input electrode 1 can be 0.3 to 2 times the channel aperture. The voltage applied to input electrode 1 can be 600 to 1200 V lower than the voltage applied to output electrode 3. In the embodiment shown in the accompanying drawings, the immersion depth of input electrode 1 is 0.3 μm, and the voltage applied to input electrode 1 is 0 V.

[0035] In some embodiments, multiplication channel 2 is made of lead-containing glass with secondary electron emission properties; the maximum secondary electron emission coefficient of multiplication channel 2 is selectable between 2 and 5; it is manufactured using a soluble glass core process; the diameter of multiplication channel 2 is selectable between 5 and 20 microns; and the inclination angle of multiplication channel 2 is selectable between 5 and 15 degrees. In the embodiment shown in the accompanying drawings, the maximum secondary electron emission coefficient of multiplication channel 2 is 4, the diameter of multiplication channel 2 is 6 microns, and the inclination angle of multiplication channel 2 is 7 degrees.

[0036] In some embodiments, the output electrode 3 is made of a material with a maximum secondary electron emission coefficient smaller than that of the nickel-chromium electrode, preferably less than 1, with the lower the better. Assuming the gain allows, the output electrode 3 is immersed as deeply as possible, preferably 1 to 3 times the diameter of the multiplication channel. The predetermined depth is achieved by controlling the positional relationship between the evaporation source and the microchannel plate. In the embodiment shown in the accompanying drawings, the maximum secondary electron emission coefficient of the output electrode 3 is 0, and the immersion depth of the output electrode 3 is 10 microns.

[0037] The main factor affecting the spatial resolution of the microchannel plate itself is the angle of the emitted electrons. The larger the angle between the emission angle and the channel axis, the greater the spatial dispersion of the output electron cloud. When the multiplied electrons are emitted, some electrons with larger emission angles will impact the output nickel-chromium electrode. The secondary electron emission coefficient of the nickel-chromium electrode of the microchannel plate reaches a maximum of 1 when the incident electron energy is 500eV. When one electron impacts the nickel-chromium electrode, at most one secondary electron is displaced, which has little effect on improving the angle of the emitted electrons. When the output electrode material is made of a material with a secondary electron emission coefficient lower than 1, electrons with larger emission angles will be absorbed by it, thereby reducing the overall dispersion of the electron emission angle. Within the range allowed by the gain, the deeper the output electrode is inserted, the smaller the dispersion of the electron emission angle and the smaller the spatial dispersion of the electrons.

[0038] Based on the above scheme, the present invention proposes selecting a material with a lower secondary electron emission coefficient than the nickel-chromium electrode and increasing the immersion depth of the output electrode. This low secondary electron emission coefficient material can be used to eliminate multiplied electrons with larger emission angles. The deeper the output electrode immersion depth, the better the elimination effect. This improves the spatial resolution of the microchannel plate.

[0039] The spatial resolution of the embodiment shown in the accompanying drawings of the present invention was simulated using the finite integration method:

[0040] In the simulation, anode 4 is set, which is 200 microns away from the output end of the microchannel plate. The voltage of anode 4 is 200V higher than that of the output electrode 3 of the microchannel plate. Figure 1 The peak half-maximum width (FWHM) of the output pulse position distribution in the X and Y directions on the anode surface is as follows: Figure 2 、 3 As shown, the results are as follows:

[0041] At the same immersion depth of the output electrode 3, the larger the maximum secondary electron emission coefficient (SEY) of the output electrode 3, the larger the FWHM of the output pulse position distribution and the lower the spatial resolution;

[0042] Under the premise of the same immersion depth of the output electrode 3, the smaller the SEY of the output electrode 3, the smaller the FWHM of the output pulse position distribution and the higher the spatial resolution;

[0043] Under the premise of the same output electrode 3SEY, the deeper the immersion depth of the output electrode 3, the smaller the FWHM of the output pulse position distribution and the higher the spatial resolution;

[0044] When the immersion depth of the output electrode 3 is 3 μm and the SEY of the output electrode 3 is 1, the FWHM in the X direction is 86 μm and the FWHM in the Y direction is 82 μm;

[0045] When the immersion depth of the output electrode 3 is 3 μm and the SEY of the output electrode 3 is 0, the FWHM in the X direction is 78 μm and the FWHM in the Y direction is 74 μm;

[0046] When the immersion depth of the output electrode 3 is 10 μm and the SEY of the output electrode 3 is 0, the FWHM in the X direction is 42 μm and the FWHM in the Y direction is 41 μm.

[0047] The present invention utilizes materials with low secondary electron emission coefficients to eliminate multiplied electrons with large emission angles, and the deeper the output electrode is immersed, the better the elimination effect. By reducing the maximum secondary electron emission coefficient of the output electrode and increasing the output electrode immersion depth, the spatial resolution of the microchannel plate can be significantly improved. The present invention is generally applicable to microchannel plates and all detection devices based on microchannel plates.

[0048] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modification, equivalent replacement and improvement made by any technician familiar with the profession to the above embodiment without departing from the scope of the technical solution of the present invention and based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A microchannel plate with improved spatial resolution, characterized by: It includes an input electrode, a multiplication channel and an output electrode; the input electrode is located at the input end of the multiplication channel, and the output electrode is located at the output end of the multiplication channel, wherein the input electrode is a nickel-chromium electrode; The multiplication channel is made of lead-containing glass with secondary electron emission performance; The output electrode is made of a material having a maximum secondary electron emission coefficient smaller than that of the nickel-chromium electrode.

2. The microchannel plate for improving spatial resolution according to claim 1, wherein: The maximum secondary electron emission coefficient of the material selected for the output electrode does not exceed 1, and the smaller the better.

3. The microchannel plate with improved spatial resolution according to claim 1, wherein: Under the premise that the gain allows, the deeper the output electrode is immersed in the multiplication channel, the better.

4. The microchannel plate with improved spatial resolution according to claim 1, wherein: The diameter of the multiplication channel is 5 to 20 microns, the inclination angle of the multiplication channel is 5 to 15 degrees, and the maximum secondary electron emission coefficient of the multiplication channel is 2 to 5.

5. The microchannel plate with improved spatial resolution according to claim 1, wherein: The depth of the input electrode immersed in the multiplication channel is 0.3 to 2 times the diameter of the multiplication channel, and the depth of the output electrode immersed in the multiplication channel is 1 to 3 times the diameter of the multiplication channel.

6. The microchannel plate with improved spatial resolution according to claim 1, wherein: The voltage of the input electrode is 600 to 1200 V lower than the voltage of the output electrode.

7. The microchannel plate with improved spatial resolution according to claim 1, wherein: An anode is arranged behind the output electrode, the distance between the anode and the output electrode is 100 to 1000 microns, and the voltage of the anode is 100 to 500V higher than that of the output electrode.

8. A method for improving the spatial resolution of a microchannel plate, characterized in that: The following steps are involved: Fabricating a microchannel plate; An input electrode is evaporated on the input surface of the microchannel plate, and an output electrode is evaporated on the output surface of the microchannel plate to obtain the microchannel plate with improved spatial resolution according to any one of claims 1 to 7.

9. The method for improving the spatial resolution of a microchannel plate according to claim 8, wherein: By controlling the positional relationship between the evaporation source and the microchannel plate, the depth of the input electrode and the output electrode immersed in the multiplication channel is controlled.

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