Neutron sensitive MCP and method of making same

Abstract

The application discloses a neutron-sensitive MCP and a manufacturing method thereof. The MCP comprises a glass substrate, and a plurality of microchannels extending from a first surface to a second surface are formed on the glass substrate. The microchannels comprise open ends and blind hole ends, and the blind hole ends are close to the second surface. An electron multiplication functional layer is arranged in the microchannels, a neutron-sensitive film layer is arranged at the second surface, and electrode layers are formed on both end surfaces. The application separates the "neutron capture" and "electron multiplication" functional areas, and the open rate of the solid sensitive film layer at the blind hole end is not limited, so that the neutron capture probability is maximized. The U-shaped microchannel realizes electron avalanche amplification. The design retains the microchannel amplification imaging function, avoids the influence of the open rate on the detection efficiency, and improves the detection efficiency.

Description

Technical Field

[0001] This invention belongs to the field of MCP development technology and relates to a neutron-sensitive MCP and its fabrication method. Background Technology

[0002] In the fields of industrial inspection and scientific research analysis, non-destructive characterization techniques for the internal structure of materials are core tools driving technological progress and innovation. Neutron imaging and X-ray non-destructive testing, as two complementary non-destructive testing methods, occupy a key position in the analysis of complex structures due to their unique physical mechanisms. X-ray technology achieves imaging by detecting the attenuation signal after rays penetrate matter. It is sensitive to high atomic number (Z) elements (such as metals) but has difficulty penetrating metals, thus hindering the detection of internal lightweight materials. Neutron imaging, on the other hand, is based on the interaction between neutrons and matter. By capturing the attenuation, scattering, or nuclear reaction signals after penetrating an object, it accurately constructs a visual image of the internal structure. It is particularly sensitive to lightweight elements (such as low-Z materials like hydrogen, carbon, lithium, and boron) and can penetrate high-density metals, making it one of the most effective means of revealing the lightweight structure and microscopic dynamic behavior of materials within metal-encased components. With breakthroughs in neutron source and detection technologies, neutron imaging has spawned advanced branches such as phase-contrast imaging, polarization imaging, and energy-resolved imaging, further expanding its application boundaries.

[0003] In the field of neutron detection, traditional high-gain microchannel plates (hMCPs) are used as core devices. These typically have apertures of 6-15 micrometers, wall thicknesses of 2-3 micrometers, aspect ratios ≥40, and electron multiplication factors reaching 10. 4 That's all. To improve neutron detection efficiency, researchers will... 6 Li, 10 B. 155 Gd, 157 High-cross-section nuclides such as Gd are introduced into the microchannel plate (MCP) design. These nuclides capture neutrons and undergo nuclear reactions, producing high-energy charged particles that penetrate the glass substrate and collide with the MCP microchannels, triggering electron avalanches and forming electron clouds. By decoding the center of these electron clouds through the anode, the incident neutron can be located, enabling imaging. 6 Li, 10 B. 155 Gd, 157 The nuclear reaction that occurs when Gd captures a neutron is:

[0004]

[0005] However, while detection efficiency is directly proportional to the molar ratio of nuclides, it is inversely proportional to the aperture ratio. The aperture ratio is a key parameter of microchannel plates, referring to the proportion of the total area of ​​the micropores that are effectively transparent to the device surface to the total surface area of ​​the device. That is, aperture ratio = total area of ​​micropores / MCP surface area × 100%. Conventional MCPs have an aperture ratio of only about 60%, resulting in the proportion of solid glass in the neutron beam being ≤40%. The core of detection efficiency is the probability of a nuclear reaction between a neutron and a sensitive nuclide. A higher molar ratio of nuclides, meaning a greater number of sensitive nuclides per unit volume, increases the probability of neutrons colliding and reacting with the nuclides, naturally leading to higher detection efficiency. A higher aperture ratio means a smaller proportion of "solid glass," i.e., the area containing sensitive nuclides. This results in a smaller effective interaction area or volume for the sensitive nuclides. When neutrons are incident, more areas are "empty channels" rather than "solid glass / film layers containing sensitive nuclides." Therefore, the number of sensitive nuclides that can react with neutrons decreases, the neutron capture rate decreases, and ultimately, the detection efficiency declines.

[0006] The current research and development of neutron-sensitive MCPs mainly follows two paths: the first path maintains the traditional MCP structure and involves doping the glass substrate. 10 B, utilizing the microporous walls 10 B traps neutrons; the second path also retains the traditional structure, but is coated on the inner wall of the microchannel. 10 B membrane layer, dependent on the channel 10 B-film neutron trapping is achieved. While both methods can achieve neutron detection, their efficiency depends entirely on... 10 The doping ratio or film thickness of boron is always limited by the inherent limitations of aperture ratio. Simulation studies show that when using oblique incidence (e.g., 1° tilt angle), the detection efficiency can be improved to some extent, but the problem of solid glass obstruction caused by aperture ratio is not fundamentally solved. For example, the 60% aperture ratio of a conventional MCP means that at most only 40% of the neutron beam can effectively trigger nuclear reactions, while the remainder is absorbed or scattered by the glass substrate, resulting in signal loss.

[0007] In summary, although the existing neutron-sensitive MCP technology has achieved a breakthrough from scratch, its detection efficiency is constrained by both aperture ratio and nuclide utilization method, making it difficult to meet the requirements of high-precision and high-efficiency neutron imaging. Summary of the Invention

[0008] To address the problems existing in the prior art, this invention provides a neutron-sensitive MCP and its fabrication method, thereby solving the technical problem of low detection efficiency of MCPs in the prior art.

[0009] This invention is achieved through the following technical solution:

[0010] A neutron-sensitive MCP includes a glass substrate having a first surface and a second surface opposite thereto, wherein a plurality of microchannels extending toward the second surface are formed on the first surface.

[0011] The microchannel includes an open end and a blind end, the open end being located on a first surface and the blind end being close to the second surface;

[0012] An electron multiplication layer is formed in the microchannel;

[0013] A neutron-sensitive film is formed on the second surface;

[0014] Electrode layers are formed on the first surface and the upper second surface.

[0015] Preferably, the pore size of the microchannel is 2~20μm; the pore spacing is 2~5μm; and the pore depth is 100~500μm.

[0016] Preferably, the thickness of the neutron-sensitive film is 1~3μm.

[0017] Preferably, the thickness at the bottom of the blind hole is 1~2μm.

[0018] Preferably, the neutron-sensitive element in the neutron-sensitive membrane layer is... 6 Li, 10 B. 155 Gd or 157 Gd.

[0019] Preferably, the electron multiplication functional layer includes a resistive layer and a secondary electron emission layer; the resistive layer is a composite layer structure of Ru and SiO2 or a composite layer structure of W and SiO2; the secondary electron emission layer is a film containing Al2O3, MgO or B2O3.

[0020] Preferably, the thickness of the electron multiplication functional layer is 100~1000nm.

[0021] Preferably, the electrode layer is a nickel-chromium alloy layer, and the thickness of the electrode layer is 0.5~2μm.

[0022] Preferably, the opening ratio of the outlet end on the first surface is 40% to 60%.

[0023] A method for fabricating a neutron-sensitive MCP includes the following steps:

[0024] A glass substrate is provided, the glass substrate having a first surface and a second surface opposite thereto, a plurality of microchannels extending toward the second surface are formed on the first surface, the microchannels including an open end and a blind end, the open end being located on the first surface and the blind end being close to the second surface;

[0025] An electron multiplication functional layer is formed in the microchannel;

[0026] A neutron-sensitive film layer is formed on the second surface;

[0027] Electrode layers are formed on the first surface and the second surface.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] This invention discloses a neutron-sensitive MCP, which forms multiple microchannels extending from a first surface of a glass substrate to a second surface. These microchannels are specifically designed as a U-shaped structure including an open end and a blind end. The blind end is close to the second surface, and a neutron-sensitive film layer is formed at this end. This design eliminates the limitation of aperture ratio on neutron capture, resulting in a 0% aperture ratio at the neutron incident end, thereby maximizing the neutron capture probability. Simultaneously, an electron multiplication layer is provided inside the microchannel. When a high voltage is applied to the U-shaped microchannel, electron avalanche amplification is achieved, ensuring signal detectability. After neutrons are captured at the blind end and generate charged particles, these particles directly enter the microchannel below to excite electrons, without needing to pass through the "empty channel," effectively avoiding neutron loss due to aperture ratio. Through this separate design of the blind-end sensitive film layer and the U-shaped microchannel, the limitation of aperture ratio on detection efficiency is successfully solved, preserving the amplification and imaging functions of the microchannel while significantly improving neutron detection efficiency. This invention addresses the problem of low detection efficiency in current neutron-sensitive MCPs by setting blind holes to reduce the aperture ratio at the MCP inlet, thereby increasing the neutron capture probability and effectively improving neutron detection efficiency.

[0030] Furthermore, the microchannels have an aperture of 2–20 μm, a spacing of 2–5 μm, and a depth of 100–500 μm. This range of microchannel sizes helps to maximize the interaction area between neutrons and the sensitive membrane while maintaining structural integrity. Appropriate aperture and spacing ensure effective penetration and trapping of the neutron beam, while sufficient depth facilitates the generation of charged particles and the amplification of electron avalanches, thereby improving detection efficiency.

[0031] Furthermore, the thickness of the neutron-sensitive film is 1~3μm. This thickness ensures sufficient nuclide material to capture neutrons while avoiding signal attenuation or increased manufacturing difficulty due to excessive film thickness.

[0032] Furthermore, the thickness at the bottom of the blind hole is 1~2μm, which ensures the stability of the blind hole structure and the uniform adhesion of the neutron-sensitive film. In addition, this thickness range helps to reduce the loss of neutrons during the penetration process and improve the efficiency of charged particle generation, thereby enhancing the intensity of the detection signal.

[0033] Furthermore, the neutron-sensitive element in the neutron-sensitive membrane layer is... 6 Li, 10 B 155 Gd or 157 Gd, using 6 Li, 10 B 155 Gd or 157 High-cross-section nuclides such as Gd, when used as neutron-sensitive film materials, can significantly improve the probability of neutron capture. These nuclides react with neutrons to produce high-energy charged particles, which form the basis for subsequent electron multiplication processes, thereby improving the detector's sensitivity and efficiency.

[0034] Furthermore, the electron multiplication functional layer includes a resistive layer and a secondary electron emission layer; the resistive layer is a composite layer structure of Ru and SiO2 or a composite layer structure of W and SiO2; the secondary electron emission layer is a film layer containing Al2O3, MgO or B2O3. The design of the electron multiplication functional layer combines the resistive layer and the secondary electron emission layer. The resistive layer provides a stable electric field environment, which helps to accelerate electrons uniformly; while the secondary electron emission layer can effectively trigger secondary electron emission and realize electron avalanche amplification. This combined design significantly enhances the signal amplification capability of the detector.

[0035] Furthermore, the thickness of the electron multiplication functional layer is 100~1000nm. This thickness range ensures electron transport efficiency while providing sufficient material to generate stable secondary electron emission. Simultaneously, this thickness range helps optimize the electron multiplication process, improving the stability and reliability of signal amplification.

[0036] Furthermore, the electrode layer is a nickel-chromium alloy layer with a thickness of 0.5~2μm. The use of nickel-chromium alloy as the electrode layer material, combined with the 0.5~2μm thickness design, ensures both the conductivity of the electrode and improves its corrosion resistance and stability. This electrode layer design helps maintain the detector's performance stability during long-term use.

[0037] Furthermore, the aperture ratio of the exit end on the first surface is 40%~60%. The present invention sets the aperture ratio of the first surface, i.e. the neutron exit end, to 40%~60% to ensure that the electron cloud generated after electron avalanche amplification can effectively escape and be collected by the electrode, thereby achieving reliable signal transmission and detection while maintaining high detection efficiency. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic cross-sectional view of the neutron-sensitive MCP in this invention;

[0040] Figure 2 This is a three-dimensional cross-sectional view of the neutron-sensitive MCP in this invention;

[0041] Figure 3 The fabrication process of the neutron-sensitive MCP in this invention is described below.

[0042] Wherein: 1, glass substrate; 11, first surface; 12, second surface; 13, microchannel; 131, opening end; 132, blind hole end. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0047] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0048] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0049] The present invention will now be described in further detail with reference to the accompanying drawings:

[0050] like Figure 1 as well as Figure 2 As shown, this invention discloses a neutron-sensitive MCP, which includes a glass substrate 1. The glass substrate 1 has a first surface 11 and a second surface 12 opposite to it. A plurality of microchannels 13 extending towards the second surface 12 are formed on the first surface 11. Each microchannel 13 includes an open end 131 and a blind end 132. The open end 131 is located on the first surface 11, and the blind end 132 is close to the second surface 12. An electron multiplication functional layer is formed in the microchannel 13. A neutron-sensitive film layer is formed on the second surface 12. Electrode layers are formed on the first surface 11 and the upper second surface 12. In use, the second surface 12 faces the neutron beam. The microchannel 13 is preferably U-shaped.

[0051] Figure 1 In this context, d represents the pore diameter of the microchannel 13, which is preferably 2μm to 15μm; D represents the pore spacing of the microchannel 13, which is 2 to 5μm; and L represents the pore depth of the microchannel 13, which is preferably 100 to 500μm.

[0052] in addition, Figure 1 In the figure, 'a' represents the sum of the thickness of the blind aperture at the MCP end and the thickness of the neutron-sensitive film. The thickness of the bottom of the blind aperture end 132 is 1~2 μm, which refers to the vertical distance between the bottom of the microchannel 13 and the second surface 12. Furthermore, the thickness of the neutron-sensitive film is 1~3 μm. The neutron-sensitive film is attached to the surface of the second surface 12. Therefore, Figure 1 In the middle, a is 2~5μm.

[0053] In addition, such as Figure 3 As shown, this invention also discloses a method for fabricating a neutron-sensitive MCP, comprising the following steps:

[0054] S1: A glass substrate 1 is provided, the glass substrate 1 having a first surface 11 and a second surface 12 opposite thereto. A plurality of microchannels 13 extending toward the second surface 12 are formed on the first surface 11. Each microchannel 13 includes an open end 131 and a blind end 132. The open end 131 is located on the first surface 11, and the blind end 132 is close to the second surface 12. The microchannel 13 is preferably U-shaped, and the resulting device is a glass substrate with a U-shaped blind hole. The second surface 12 serves as the MCP inlet end.

[0055] Specifically, in the manufacturing process, the glass substrate 1 is first modified and the modified area is etched to obtain a glass substrate with U-shaped blind holes.

[0056] The glass substrate 1 is a transparent glass substrate.

[0057] Preferably, laser modification is used. Here, laser modification refers to altering the structure and acid / alkali corrosion resistance of the glass substrate 1 material in the irradiated area using a laser. The modified glass is then easily corroded. When using laser modification on a transparent glass substrate 1, the laser acts on the blind hole area, i.e. Figure 2 The blue area in the image. The laser is incident obliquely on glass substrate 1, with an angle of ≤1°.

[0058] The laser modification process involves using a femtosecond or picosecond ultrafast pulsed laser. Leveraging its ultra-high energy density and extremely short pulse width, it induces selective changes in the physicochemical structure of the blind hole region in a transparent glass substrate 1. Laser photons, through multiphoton absorption or tunneling ionization, break atomic bonds and distort the crystal lattice in localized areas of the glass, forming a "modified region." This region exhibits a significant difference in chemical stability compared to the unmodified region, resulting in a subsequent etching rate difference of ≥50 times, thus providing a basis for selective etching. The laser is applied to the blind hole region of the glass substrate 1 at an oblique incident angle ≤1° (the blue area in Figure 2). Through array-type beam scanning, a modified pattern corresponding to the U-shaped microchannel is formed inside the glass. After laser modification, the local chemical composition and bonding state of the glass undergo irreversible changes. Specifically, the connectivity of the silicon-oxygen tetrahedral network decreases, the number of non-bridging oxygen atoms increases, and defect states are formed. This leads to a much higher dissolution rate in acidic or alkaline solutions compared to the unmodified region.

[0059] The above etching process involves alternating etching with acidic and alkaline solutions. Specifically, when the laser-modified glass substrate is placed in an acidic or alkaline solvent, the corrosion rate of the modified area is at least 50 times faster than that of the unmodified area. After repeated acid and alkaline wet etching, the laser-modified area is completely dissolved, leaving a glass substrate with blind holes, i.e., a glass substrate with U-shaped blind holes.

[0060] When alternating etching with acidic and alkaline solutions:

[0061] The acidic solution is HF, HCl, HNO3, or H2SO4, and its mass percentage concentration is 1% to 10%.

[0062] The alkaline solution is NaOH or KOH, and its mass percentage concentration is 5% to 10%.

[0063] The etching time for one acidic solution etching is 0.5~1h, and the temperature is room temperature;

[0064] The etching time for one alkaline solution etching is 5-10 hours at room temperature;

[0065] The alternating etch cycles are repeated 3 to 5 times.

[0066] S2: An electron multiplication functional layer is formed in the microchannel 13;

[0067] That is, an electron multiplication functional layer is formed in the microchannel of the glass substrate with U-shaped blind holes;

[0068] More specifically, the electron multiplication functional layer includes a resistive layer and a secondary electron emission layer;

[0069] The resistive layer is a composite layer structure of tungsten (W) and aluminum oxide (Al2O3), i.e., W / Al2O3, or a composite layer structure of ruthenium (Ru) and Al2O3, i.e., Ru / Al2O3, preferably W / Al2O3;

[0070] The secondary electron emission layer is Al2O3, MgO, or B2O3, with Al2O3 being preferred.

[0071] In this step, an electron multiplication functional layer is specifically prepared in a microchannel of a glass substrate with U-shaped blind holes using atomic layer deposition technology.

[0072] During the deposition process, a resistive layer is deposited first, followed by a secondary electron emission layer. The resistive layer needs to be directly bonded to the glass substrate 1 to regulate the electric field distribution within the microchannel 13, providing a stable conductive environment for subsequent electron multiplication. The resistive layer provides a stable electric field environment, ensuring that secondary electron emission is efficiently triggered when electrons collide with the Al2O3 surface.

[0073] When the resistive layer is a composite layer structure of tungsten (W) and aluminum oxide (Al₂O₃), the deposition process is as follows: A single-atom layer of W and Al₂O₃ is sequentially deposited on the substrate surface by alternately introducing a tungsten precursor (such as WF₆) and an aluminum precursor (trimethylaluminum, TMA). This forms a nanoscale alternating layered structure of W and Al₂O₃, with the thickness of each layer precisely controlled in the sub-nanometer to several-nanometer range. The W layer provides localized conductivity, preventing charge accumulation that could lead to electric field distortion; the Al₂O₃ layer acts as an insulating spacer, suppressing continuous conductive paths and preventing current overload or breakdown. By adjusting the W / Al₂O₃ layer ratio, the resistivity can be precisely controlled.

[0074] In one specific embodiment, when the resistive layer is prepared by atomic layer deposition, the process is a self-limiting surface reaction. The resistive layer is W / Al2O3 or Ru / Al2O3. The precursors for the Al2O3 coating are trimethylaluminum (TMA, Al(CH3)3) and water, the precursor for W is WF6, and the precursor for Ru is ruthenium dicene (RuCp2, Ru(C5H5)2).

[0075] Taking Ru / Al₂O₃ deposition as an example, the chamber temperature was 300℃ during the deposition process. Nitrogen (99.99%) was used as the transport gas at a flow rate of 400 sccm. The two precursors were introduced into the reaction chamber sequentially, with gas purification performed between them. The cycling sequence for Al₂O₃ preparation was TMA / N₂ / H₂O / N₂ (1 sec / 20 sec / 1 sec / 10 sec), and the sequence for Ru was RuCp₂ / N₂ / O₂ / N₂ (2 sec / 45 sec / 2 sec / 45 sec). The deposition rate for Al₂O₃ was approximately 0.2 nm per cycle, and for Ru, approximately 0.062 nm per cycle. The thin film prepared using atomic layer deposition (ALD) technology has a smooth, dense surface with low roughness and excellent thermal and chemical stability. It can effectively improve the roughness of the channel inner wall, reduce dark count, and improve gain and lifespan.

[0076] The thickness of a single W or Ru layer is preferably 0.14 nm;

[0077] The thickness of a single Al2O3 layer is preferably 0.12 nm;

[0078] The thickness of the resistive layer is preferably 50nm~100nm;

[0079] The thickness of the electron multiplication functional layer is preferably 100~1000 nm;

[0080] The number of alternating deposition layers is preferably 50 to 200;

[0081] In one specific embodiment, the deposition process of the resistive layer is as follows:

[0082] S3: A neutron-sensitive film layer is formed at the second surface 12, that is, a neutron-sensitive film layer is formed on the outside of the blind hole end 132 on the device after step S2.

[0083] In the fabrication process of neutron-sensitive U-shaped microchannel plates (MCPs), the deposition of the neutron-sensitive film is a key step in realizing the core functionality. In this step, the neutron-sensitive film is fabricated on the second surface 12 using magnetron sputtering or electron beam evaporation techniques. 6 Li, 10 B. 155 Gd, 157 Gd and other films can achieve neutron detection performance.

[0084] When a neutron-sensitive film is prepared on the second surface 12 by magnetron sputtering, the specific steps are as follows:

[0085] The target material is a nickel-chromium alloy target material;

[0086] Adjust the angle between the target and the substrate to 0°~10°;

[0087] The vacuum level inside the magnetron sputtering cavity is 0.1~0.5 Pa.

[0088] The deposition temperature is 20°~80°;

[0089] The sputtering power is 100W;

[0090] The deposition rate is 30~50 sccm.

[0091] After deposition, the substrate is slowly cooled in a vacuum or inert gas to prevent the film from cracking.

[0092] When a neutron-sensitive film layer is prepared on the second surface 12 using electron beam evaporation, the specific steps are as follows:

[0093] The target material is nickel-chromium alloy powder;

[0094] Adjust the angle between the target and the substrate to 0°~10°

[0095] The vacuum level inside the cavity is 10. -3 ~10 -4 Pa.

[0096] The deposition temperature is 20°~80°;

[0097] The deposition rate is 30~50 sccm.

[0098] When the film thickness reaches the designed value of 200nm~500nm, the electron beam is turned off and the cavity is filled with inert gas for cooling.

[0099] S4: An electrode layer is formed on the first surface 11 and the second surface 12.

[0100] The second surface 12 is the area where neutrons are incident and the sensitive film layer is attached. The electrode layer located on this surface needs to cover the non-sensitive film area on this surface, or be insulated from the sensitive film layer to avoid affecting neutron capture.

[0101] The glass substrate with the secondary electron multiplication functional layer does not yet possess the function of a microchannel plate (MCP). Therefore, metal layers must be fabricated as electrode layers on the upper surface (second surface 12) and the lower surface (first surface 11) of the MCP to facilitate the application of high voltage. In this invention, the electrode layer is a nickel-chromium alloy layer.

[0102] This invention forms a blind aperture directly at the MCP inlet and prepares a neutron-sensitive film layer, resulting in a 0% aperture ratio at the neutron incident end. This structure can achieve the maximum probability of capturing neutrons and effectively avoids the problem of the MCP aperture ratio affecting neutron detection efficiency.

[0103] In neutron detection, "signal generation" and "signal amplification" are two independent but necessary steps. The "hole" in the MCP, i.e., microchannel 13, is not for neutron capture, but for electron multiplication, i.e., signal amplification. Any neutron detection based on MCP is essentially a chain of "neutron → charged particle → electron → signal amplification." The first step: neutron capture and charged particle generation. Neutrons are uncharged and cannot be directly detected; they must be captured by a neutron-sensitive nuclide (such as...). 10 B. 6 The nuclear reaction of Li produces charged particles; the second step is electron multiplication and signal amplification. The charged particles produced by the nuclear reaction have limited energy, resulting in a very small number of initially excited electrons and a signal too weak to be directly detected. The signal must be amplified through the electron multiplication effect of the microchannel 13 in the MCP. The inner wall of microchannel 13 has a secondary electron emission layer (such as Al2O3). Charged particles collide with the inner wall, generating a small number of secondary electrons. A high voltage is applied across microchannel 13, forming an electric field along the channel axis. Electrons are accelerated by the electric field and repeatedly collide with the channel wall, generating an avalanche of secondary electrons. The amplified electron signal is collected by electrodes and converted into a detectable electrical signal, such as current or voltage pulses. The contradiction of conventional MCPs lies in the fact that the presence of microchannels increases the aperture ratio, reduces the proportion of solid glass, and decreases the total amount of sensitive nuclides, affecting neutron capture efficiency; however, without microchannels, electron multiplication cannot be achieved, affecting signal detection. Therefore, existing technologies can only trade off between "aperture ratio" and "detection efficiency." The aperture ratio is usually designed to be 60%-80%, ensuring a sufficient number of microchannels to achieve uniform electron multiplication while retaining a certain proportion of solid glass for doping sensitive nuclides. However, this design is essentially a "compromise," resulting in detection efficiency being limited by the aperture ratio. This invention separates the functional regions of "neutron capture" and "electron multiplication," completely solving the problem of the impact of aperture ratio on detection efficiency. The "solid sensitive film layer" at the blind aperture end 132 has no aperture ratio limitation, forming a neutron capture region with a 100% proportion of sensitive nuclides, maximizing the neutron capture probability. Applying a high voltage to the U-shaped microchannel 13 achieves electron avalanche amplification, ensuring signal detectability and forming an electron multiplication region. Neutrons are captured at the blind aperture end 132 and generate charged particles, which directly enter the microchannel 13 below to excite electrons without passing through the "empty channel." Through structural synergy, the amplification and imaging functions of the microchannel are retained while avoiding the impact of aperture ratio on detection efficiency. Therefore, by separating the sensitive membrane layer at the blind end 132 from the U-shaped microchannel 13, the present invention effectively overcomes the contradiction between the aperture ratio and detection efficiency of conventional MCPs, and significantly improves the detection efficiency.

[0104] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A neutron-sensitive MCP, characterized in that, It includes a glass substrate (1), the glass substrate (1) having a first surface (11) and a second surface (12) opposite thereto, and a plurality of microchannels (13) extending toward the second surface (12) are formed on the first surface (11). The microchannel (13) includes an open end (131) and a blind end (132). The open end (131) is located on the first surface (11), and the blind end (132) is close to the second surface (12). An electron multiplication functional layer is formed in the microchannel (13); A neutron-sensitive film is formed at the second surface (12); Electrode layers are formed on the first surface (11) and the upper second surface (12); The formation process of the microchannel (13) is as follows: the glass substrate (1) is locally modified by femtosecond or picosecond pulsed laser, and the modified glass substrate (1) is etched alternately by acidic solution and alkaline solution to form the microchannel (13). The neutron-sensitive film is prepared by using magnetron sputtering or electron beam evaporation to prepare the neutron-sensitive film on the second surface (12). The electrode layer on the second surface (12) is located outside the neutron-sensitive film layer; The microchannel (13) has a pore size of 2~20μm; a pore spacing of 2~5μm; a pore depth of 100~500μm; and the microchannel (13) has a U-shaped structure. The thickness of the bottom of the blind hole end (132) is 1~2μm; The thickness of the neutron-sensitive membrane is 1~3μm.

2. The neutron-sensitive MCP according to claim 1, characterized in that, The neutron-sensitive element in the neutron-sensitive membrane is: 6 Li, 10 B. 155 Gd or 157 Gd.

3. A neutron-sensitive MCP according to claim 1, characterized in that, The electron multiplication functional layer includes a resistive layer and a secondary electron emission layer; the resistive layer is a composite layer structure of Ru and SiO2 or a composite layer structure of W and SiO2; the secondary electron emission layer is a film containing Al2O3, MgO or B2O3.

4. A neutron-sensitive MCP according to claim 1, characterized in that, The thickness of the electron multiplication functional layer is 100~1000nm.

5. A neutron-sensitive MCP according to claim 1, characterized in that, The electrode layer is a nickel-chromium alloy layer, and the thickness of the electrode layer is 0.5~2μm.

6. A neutron-sensitive MCP according to claim 1, characterized in that, The opening ratio of the outlet end on the first surface (11) is 40%~60%.

7. A method for fabricating a neutron-sensitive MCP according to any one of claims 1 to 6, characterized in that, Includes the following steps: A glass substrate (1) is provided, the glass substrate having a first surface (11) and a second surface (12) opposite thereto, a plurality of microchannels (13) extending toward the second surface (12) are formed on the first surface (11), the microchannels (13) include an open end (131) and a blind end (132), the open end (131) is located on the first surface (11), and the blind end (132) is close to the second surface (12). An electron multiplication functional layer is formed in the microchannel (13); A neutron-sensitive film is formed at the second surface (12); Electrode layers are formed on the first surface (11) and the second surface (12).

Images