Method for suppressing ultraviolet light response of microchannel plate and microchannel plate

Abstract

The present invention provides a method for suppressing the ultraviolet light response of a microchannel plate and a microchannel plate. On the basis of the MCP background, a functional film layer material with a large bandgap, high ultraviolet light transmittance and high secondary electron emission coefficient is plated on the input surface and the channel of the microchannel plate by physical vapor deposition or evaporation, such as a single film layer material such as lanthanum oxide, silicon oxide, aluminum oxide, aluminum nitride, silicon nitride, magnesium oxide, magnesium fluoride, or a composite film layer formed by multiple materials thereof. By preparing such a functional film layer, the response of the MCP to the ultraviolet light signal can be significantly suppressed, and the response degree of the MCP to the ultraviolet light can be reduced by more than two orders of magnitude.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric detection and particle detection, and in particular to a microchannel plate (MCP) capable of suppressing ultraviolet light signal response and applicable to detecting particles and radiation. Background Art

[0002] Micro-channel Plate (MCP) is a two-dimensional electron multiplier array composed of millions (e.g. 2 million to 6 million) of parallel channel electron multiplier units. It can detect charged particles, electrons, X-rays and UV photons, etc. It has the advantages of high gain, small size, good time characteristics, high spatial resolution, strong magnetic field resistance, low power consumption, self-saturation, etc. In addition to being used in low-light image intensifiers, it is also used as a core amplifier in a variety of fields, such as space particle detection, ion detection, neutrino detection and other scientific and experimental, industrial detection fields.

[0003] Conventional MCPs have certain responses to various types of signals, and there are certain differences in the degree of response, that is, for different signal types, the detection efficiency of MCP is different. For example, for electron detection, when the energy is appropriate, the detection efficiency is usually around 70%, and through some special treatments, the detection efficiency can reach nearly 100%. For ion detection, the detection efficiency is usually 40~70%; for X-rays, the detection efficiency is relatively low, usually 1~10%; for ultraviolet light, it also has a certain detection efficiency, generally not more than 15%, and is greatly related to the wavelength. For ultraviolet light with a wavelength exceeding 200nm, the detection efficiency will decay to about 0.01%.

[0004] When using MCP for weak signal detection, ideally, there is only one signal, the target signal to be detected. At this time, the main factors affecting the signal detection effect are the detection efficiency of this signal and the background noise of MCP. However, more often, in addition to the target signal type, there will be other types of signals in the signal incident on MCP, and MCP can also respond. For the detection of target signals, the response generated by other types of signals is also a kind of noise. Therefore, for the detection of characteristic signals among multiple signals, if the response suppression of non-target signals can be achieved, the signal-to-noise ratio and other performance of signal detection can be significantly improved, and even the feasibility of detection can be determined.

[0005] The weak signals to be detected can be broadly divided into two categories: one is physical particles, such as electrons, ions, neutral particles, muons, neutrons, etc., which can be divided into charged particles and uncharged particles; the other is radiation, such as ultraviolet light, X-rays, gamma rays, etc. When multiple signals are mixed together, the existing signal screening methods include: electric field, thin film isolation, optical system screening, time-resolved screening, etc. However, when uncharged particles are mixed with radiation signals, and the target signal is a neutral particle, it is difficult to filter out the radiation signal (such as ultraviolet light) through the front-end system of MCP, and the response range of the core detector needs to be changed to achieve selective detection of the signal. Summary of the invention

[0006] The purpose of the present invention is to provide a method for suppressing the ultraviolet light response of a microchannel plate and a microchannel plate, by preparing a special functional film layer on the surface of the MCP and the inner wall of the channel to suppress the response of the microchannel plate to ultraviolet light, while ensuring that it has a high secondary electron emission capability and will not affect the microchannel plate's own signal detection and multiplication functions.

[0007] According to the purpose of the present invention, a method for suppressing the ultraviolet light response of a microchannel plate is proposed, by preparing a composite film layer for suppressing the ultraviolet light response on the input surface of an array electron multiplier formed by millions of mutually parallel channel electron multiplier units and the inner wall of the channel of each electron multiplier unit, the composite film layer is composed of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, so that a trend of gradually increasing barrier height from the inside to the outside or a trend of fluctuation of barrier height is formed between the multiple film layers in the composite film layer, thereby suppressing the escape of photoelectrons excited by ultraviolet light.

[0008] According to the purpose of the present invention, a microchannel plate for suppressing ultraviolet light response is also proposed, and a composite film layer for suppressing ultraviolet light response is prepared on the input surface of an array-type electron multiplier formed by millions of mutually parallel channel-type electron multiplier units and the inner wall of the channel of each electron multiplier unit. The above-mentioned composite film layer is composed of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, so that a trend of gradually increasing barrier height from the inside to the outside or a trend of fluctuating barrier height is formed between the multiple film layers in the composite film layer, thereby suppressing the escape of photoelectrons excited by ultraviolet light.

[0009] According to a first aspect of the present invention, a microchannel plate for suppressing ultraviolet light response is provided, comprising:

[0010] An array-type electron multiplier composed of millions of mutually parallel channel-type electron multiplying units, each electron multiplying unit forming a microchannel structure; the array-type electron multiplier defines an input surface; and

[0011] A composite film layer for suppressing ultraviolet light response is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, the composite film layer comprising at least two layers of a first film layer and a second film layer prepared in sequence with high ultraviolet light transmittance and high secondary electron emission coefficient, the first film layer is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, and the second film layer is prepared on the first film layer;

[0012] Wherein, the bandgap width of the second film layer in the composite film layer is greater than the bandgap width of the first film layer.

[0013] Among the composite film layers, the outermost film layer has the highest bandgap width.

[0014] In another embodiment, the composite film layer further includes a third film layer prepared on the second film layer;

[0015] The bandgap widths of the first film layer, the second film layer and the third film layer show a trend of increasing successively.

[0016] In the above embodiment, the composite film layer adopts multiple single-layer film layers to form a multi-layer film structure by stacking them in sequence, wherein the bandgap width shows a trend of increasing from the inside to the outside. For example, taking the three-layer film layer ABC as an example, the film layer A with the lowest bandgap width is first prepared and made on the MCP background, and then the film layer B with an intermediate bandgap width is prepared in sequence and made on the surface of the film layer A. It is located in the middle layer position, and the outermost film layer C has the highest bandgap width, thereby realizing a gradual increase in the barrier height from the inside to the outside, which plays a role in suppressing the escape of photoelectrons excited by ultraviolet light.

[0017] According to a second aspect of the present invention, a microchannel plate for suppressing ultraviolet light response is provided, comprising:

[0018] An array-type electron multiplier composed of millions of mutually parallel channel-type electron multiplying units, each electron multiplying unit forming a microchannel structure; the array-type electron multiplier defines an input surface; and

[0019] A composite film layer for suppressing ultraviolet light response is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, and the composite film layer includes a multilayer stacked structure formed by regularly stacking at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, wherein the bandgap widths of the at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient are different.

[0020] In the above embodiments, the composite film layer adopts a multilayer stacking structure formed by regularly stacking at least two single film layers. For example, taking film layer AB in 2 as an example, when the stacking structure is made on the MCP background, a multilayer stacking structure of AB / AB / … / AB is formed, wherein film layer AB is made of two materials with a large difference in bandgap width. As a result, the barrier height of the manufactured composite film layer fluctuates, which plays a role in suppressing the escape of photoelectrons excited by ultraviolet light.

[0021] According to a third aspect of the present invention, a method for suppressing ultraviolet light response of a microchannel plate is also provided, comprising the following steps:

[0022] A composite film layer for suppressing ultraviolet light response is prepared on the input surface of an array electron multiplier formed by millions of mutually parallel channel-type electron multiplier units and the inner wall of the channel of each electron multiplier unit. The composite film layer is composed of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, so that a trend of gradually increasing barrier height from the inside to the outside or a trend of fluctuating barrier height is formed between the multiple film layers in the composite film layer, thereby suppressing the escape of photoelectrons excited by ultraviolet light.

[0023] The composite film layer comprises at least two film layers prepared in sequence with high ultraviolet light transmittance and high secondary electron emission coefficient, one of which is prepared on the input surface and the inner wall of the channel of each electron multiplication unit, and the outermost film layer has the highest bandgap width;

[0024] Alternatively, the composite film layer comprises a multilayer stacked structure formed by regularly stacking at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, wherein the at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient have different bandgap widths.

[0025] The response of MCP to ultraviolet light mainly comes from two aspects: one is the metal electrode on the input surface of MCP. The metal work function is not high and can be excited by ultraviolet light to produce free electrons to escape and perform cascade multiplication output in the MCP channel; the other is the semiconductor functional film layer inside the MCP channel. The bandgap width is small and can be excited by ultraviolet light to produce electrons to escape and perform cascade multiplication output.

[0026] Compared with the prior art, in the method for suppressing the ultraviolet light response of a microchannel plate and the design of the microchannel plate proposed by the present invention, on the one hand, a single / composite functional film layer material with a large bandgap width, high ultraviolet light transmittance and a high secondary electron emission coefficient is prepared on the surface of the MCP input surface and in the channel by plating / deposition, etc., and the ultraviolet light response is suppressed from two aspects: one is the response generated by the MCP matrix, the composite functional film layer has a high transmittance and low absorption rate for ultraviolet light, the absorption of ultraviolet light mainly depends on the background MCP, and the probability of photoelectrons generated by absorbing ultraviolet light passing through this functional film layer material to form free electrons is very low, thereby achieving the suppression of ultraviolet light response; the second is the ultraviolet light response generated by the functional film layer, because the functional film layer has a large bandgap width, the absorbed ultraviolet light is difficult to excite free electrons to escape, thereby suppressing the ultraviolet light response.

[0027] At the same time, in the method design of the present invention, the composite functional film layer has a high secondary electron emission capability while achieving the suppression of ultraviolet light response, and will not affect the MCP's own signal detection and multiplication functions.

[0028] As a preferred solution, when a composite functional film layer is used to enhance the ability to suppress ultraviolet light response, the following methods can be used: 1) When a multilayer film structure is made on an MCP substrate, such as three material film layers A, B, and C, the first film layer A made should have the lowest bandgap width among the three, the middle film layer has a middle bandgap width, and the outermost layer C material should have the highest bandgap width. This design method can achieve a gradual increase in the barrier height from the inside to the outside, thereby maximizing the escape suppression effect of photoelectrons stimulated by ultraviolet light; 2) When a stacked structure is made on an MCP substrate, such as AB / AB / … / AB, two materials with a large difference in bandgap width are selected, and the barrier height of the functional film layer made varies, which provides greater resistance to the escape of photoelectrons.

[0029] Therefore, the composite functional film layer is deposited through the input surface and the inner wall of the channel according to the design of the present invention, so as to achieve the effect of significantly suppressing the response of MCP to ultraviolet light signals, and reduce the response degree of MCP to ultraviolet light by more than two orders of magnitude, thereby improving the response characteristics of MCP. Moreover, through the implementation of the method of the present invention, the aperture, bevel angle, external dimensions, etc. of MCP are not limited, and the method has wide applicability.

[0030] 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.

[0031] 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

[0032] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0033] Figure 1a This is a schematic diagram of the microchannel structure of a conventional MCP. Figure 1b yes Figure 1a Schematic diagram of the response principle of MCP to ultraviolet light.

[0034] Figure 2a , 2b Schematic diagram of an MCP structure having a composite film layer for suppressing ultraviolet light response according to an exemplary embodiment of the present invention, wherein Figure 2a The input surface and the inner part of the channel are prepared in the depth range. Figure 2b The input surface and the entire channel are connected inside the preparation method.

[0035] Figure 3 FIG. 1 is a schematic diagram of the response principle of the MCP with a composite film layer that suppresses ultraviolet light response according to an exemplary embodiment of the present invention to ultraviolet light, Figure 2b The method shown in the figure is used to prepare the MCP composite membrane layer as an example.

[0036] Figure 4 This is a graph showing the relationship between the UV suppression effect and the film thickness of a composite film prepared using ALD technology.

[0037] Description of reference numerals:

[0038] 10- channel inner wall of the microchannel structure;

[0039] 11-composite film layer prepared on the input surface;

[0040] 12-composite membrane layer prepared on the inner wall of the channel;

[0041] 100-UV signal;

[0042] 200-The photoelectrons excited by ultraviolet light on conventional MCP all escape from the surface;

[0043] 201-Photoelectrons generated by the MCP background that failed to escape the surface;

[0044] 202-Suppresses the small amount of photoelectrons generated by UV-responsive MCP. DETAILED DESCRIPTION

[0045] 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.

[0046] 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.

[0047] Combination Figure 1a , 1b As shown in the figure, on the basis of the conventional MCP background, when receiving ultraviolet radiation, the MCP responds, the ultraviolet light excites free electrons to escape, and cascade multiplication output is performed in the MCP channel. At the same time, due to the small bandgap width of the internal semiconductor functional film layer prepared on the inner wall of the channel, it can be excited by ultraviolet light to generate electrons to escape and perform cascade multiplication output, which leads to Figure 1b In the MCP ultraviolet response schematic diagram shown, when receiving ultraviolet radiation, the MCP produces more ultraviolet response and stimulates photoelectrons 200, all of which escape from the inner wall of the channel and the surface of the input surface. When using the MCP as a detection device to detect weak signals, it will affect the detection efficiency and response characteristics of the target signal.

[0048] Based on this problem, the present invention proposes a method for suppressing the ultraviolet light response of a microchannel plate, by preparing a composite film layer for suppressing the ultraviolet light response on the input surface of an array-type electron multiplier formed by millions of mutually parallel channel-type electron multiplier units and the inner wall of the channel of each electron multiplier unit. The composite film layer is composed of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, so that a trend of gradually increasing barrier height from the inside to the outside or a trend of fluctuating barrier height is formed between the multiple film layers in the composite film layer, thereby suppressing the escape of photoelectrons excited by ultraviolet light.

[0049] According to the disclosure of the present invention, a microchannel plate for suppressing ultraviolet light response is also proposed. A composite film layer for suppressing ultraviolet light response is prepared on the input surface of an array-type electron multiplier formed by millions of mutually parallel channel-type electron multiplier units and the inner wall of the channel of each electron multiplier unit. The composite film layer is composed of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, so that a trend of gradually increasing barrier height from the inside to the outside or a trend of fluctuating barrier height is formed between the multiple film layers in the composite film layer, thereby suppressing the escape of photoelectrons excited by ultraviolet light.

[0050] Combination Figure 2a , 2b The examples shown respectively represent examples of preparing a composite film layer for suppressing ultraviolet light response on the input surface of a microchannel plate and the inner wall of the channel.

[0051] In a schematic diagram of a microchannel plate for suppressing ultraviolet light response in one embodiment, it includes an array electron multiplier and a composite film layer for suppressing ultraviolet light response prepared on the input surface and the inner wall of the channel of the array electron multiplier.

[0052] The aforementioned array electron multiplier refers to an array electron multiplier composed of millions of parallel channel electron multiplier units, which is usually made of skin glass and core glass as raw materials, and is an MCP background made through wire drawing, wire drawing, screen arrangement, screen pressing, screen cutting, polishing, corrosion, and hydrogen reduction processes.

[0053] Based on the MCP background, electrodes and functional film layers, such as anti-reflection films, high-resistance films, etc., can be further prepared to obtain finished MCP devices.

[0054] In an embodiment of the present invention, each electron multiplying unit constitutes a microchannel structure.

[0055] Figure 2a The structural example shown is an example of a microchannel structure of an array electron multiplier, namely, an MCP background, wherein reference numeral 10 represents the inner wall of the channel, and the area between two channel inner walls constitutes a microchannel.

[0056] A composite film layer for suppressing ultraviolet light response is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, including an input surface composite film layer 11 located on the input surface and an inner wall composite film layer 12 located on the inner wall of the channel.

[0057] The input surface composite film layer 11 and the inner wall composite film layer 12 located on the inner wall of the channel adopt the same film layer structure and materials, and both include at least two layers of a first film layer and a second film layer prepared in sequence with high ultraviolet light transmittance and a high secondary electron emission coefficient, wherein the first film layer is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, and the second film layer is prepared on the first film layer; and the bandgap width of the second film layer in the composite film layer is greater than the bandgap width of the first film layer.

[0058] In an embodiment of the present invention, the material of each layer of the composite film layer is selected to have a large bandgap width, high ultraviolet light transmittance and a high secondary electron emission coefficient, including one of lanthanum oxide, silicon oxide, aluminum oxide, aluminum nitride, silicon nitride, magnesium oxide, and magnesium fluoride.

[0059] In an optional embodiment, the preparation of the ultraviolet light response suppression composite film layer can be made by physical vapor deposition methods such as electron beam evaporation, thermal evaporation, ion plating, etc., and can also be made by atomic layer deposition technology.

[0060] exist Figure 2a In the example shown, the composite film layer uses multiple single film layers that are stacked in sequence to form a multi-layer film structure, in which the bandgap width shows a trend of increasing from the inside to the outside, that is, among the single film layers of the composite film layer, the outermost film layer has the highest bandgap width.

[0061] For example, taking three-layer film layer ABC as an example, first, film layer A with the lowest bandgap width is made on the MCP background, and then film layer B with an intermediate bandgap width is made on the surface of film layer A, which is located in the middle layer position, and finally the outermost film layer C is prepared. The outermost film layer C has the highest bandgap width, thereby achieving a gradual increase in the barrier height from the inside to the outside, which plays a role in suppressing the escape of photoelectrons excited by ultraviolet light.

[0062] In other embodiments, the composite film layer may also form a multilayer film structure by stacking more (for example, four layers or more) or fewer (for example, two layers) single film layers in sequence, and ensure that the outermost film layer has the highest bandgap width.

[0063] In other embodiments, in addition to using the aforementioned multi-layer film structure formed by sequentially stacking multiple single-layer film layers of different materials, the composite film layer can also use a multi-layer stacked structure formed by regular superposition to form a more optimized photoelectron escape suppression, thereby suppressing the escape of photoelectrons excited by ultraviolet light.

[0064] In an optional embodiment, the composite film layer is also configured to include a multilayer stacked structure composed of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficients regularly stacked, wherein the bandgap widths of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficients are different.

[0065] As mentioned above, at least two film layers having high ultraviolet light transmittance and high secondary electron emission coefficient can be selected from lanthanum oxide, silicon oxide, aluminum oxide, aluminum nitride, silicon nitride, magnesium oxide, and magnesium fluoride.

[0066] For example, taking two film materials A and B with a large difference in bandgap width as an example, when a multilayer stacked structure is made on an MCP substrate, such as AB / AB / … / AB, it is made by physical vapor deposition methods such as electron beam evaporation, thermal evaporation, ion plating, or ALD, so that the barrier height of the functional film layer produced fluctuates, which provides greater resistance to the escape of photoelectrons.

[0067] In an alternative embodiment, in combination Figure 2a As shown, the coverage of the composite film layer includes the entire input surface and the predetermined depth of the inner wall of the channel of each electron multiplying unit. For example, the composite film layer for suppressing ultraviolet light response is made by physical vapor deposition such as electron beam evaporation, thermal evaporation, and ion plating, and the depth of the composite film layer prepared on the inner wall of the channel of each electron multiplying unit ranges from 3D to 20D, where D is the inner diameter of the channel of each electron multiplying unit.

[0068] In another embodiment, for a microchannel plate with a bevel angle of θ, the depth of the composite film layer prepared on the inner wall of the channel of each electron multiplying unit is greater than 1 / tan(θ).

[0069] In an embodiment of the present invention, the thickness of the composite film layer is in the range of 2 nm to 50 nm.

[0070] In another embodiment, the input surface composite film layer 11 and the inner wall composite film layer 12 can both be prepared by atomic layer deposition technology (ALD), and a composite film layer of the above-mentioned single material or multi-layer materials is deposited on the MCP input surface and the inner wall of the channel, and the total layer thickness of the composite film layer ranges from 2nm to 50nm.

[0071] Figure 2b The structural example shown is another example of a microchannel structure of an array electron multiplier, i.e., an MCP background, wherein reference numeral 1 represents an input surface composite membrane layer located on the input surface, and reference numeral 12 represents an inner wall composite membrane layer located on the inner wall of the channel. In a particularly preferred example, the input surface composite membrane layer 11 and the inner wall composite membrane layer 12 have the same thickness.

[0072] exist Figure 2bIn the example shown, the coverage area of ​​the composite film layer includes the entire input surface and the entire through channel inner wall of each electron multiplying unit, that is, the composite film layer located at the channel inner wall covers the entire inner wall surface.

[0073] Figure 3 The exemplary embodiment shows Figure 2b The microchannel structure and the composite film layer for suppressing ultraviolet light response prepared therefrom are shown as an example, and the response diagram when subjected to ultraviolet light radiation is shown, wherein 201 represents the photoelectrons generated by the MCP background that cannot escape from the surface, and the reference numeral 202 represents a small amount of photoelectrons generated by the MCP for suppressing ultraviolet response.

[0074] Based on the above-mentioned embodiments of the present invention, the composite film layer for suppressing ultraviolet light response prepared on the input surface of the MCP and inside the channel (through mode) is made of two single-layer film layers made of materials with large bandgap width differences, and the laminated structure is formed alternately. The barrier height fluctuates, providing resistance to the escape of photoelectrons excited by ultraviolet response, and suppressing their escape from the inner wall of the channel or the surface of the input surface. In this way, the interference of ultraviolet response received by the MCP in the process of realizing the detection of target weak signals is reduced, and the detection efficiency and response characteristics of target weak signals are improved.

[0075] As an example, the process of coating a composite film layer by physical vapor deposition mainly includes:

[0076] (1) Prepare MCP with plated electrodes (such as NiCr electrodes), with no restrictions on the MCP aperture, bevel angle and size;

[0077] (2) According to the structure and material property requirements of the composite film layer of the aforementioned embodiment, prepare selected coating materials, such as lanthanum oxide, silicon oxide, aluminum oxide, aluminum nitride, silicon nitride, magnesium oxide, magnesium fluoride, etc., and place the required coating materials into the multi-crucible of the coating machine respectively;

[0078] (3) The MCP is loaded into the fixture and placed on the coating machine with the coating angle adjusted. The coating depth on the inner wall of the channel can be controlled by adjusting the coating angle, which can reach 3D to 20D, where D is the inner diameter of the channel;

[0079] (4) Setting appropriate coating parameters and running the coating process can produce a single film layer or a composite film layer, and the total thickness of the composite film layer is controlled in the range of 2nm to 50nm.

[0080] As a preferred solution, in the aforementioned step (3), the clamp may be a clamp capable of correcting / adjusting the bevel angle.

[0081] In order to achieve a better suppression effect and ensure that there is a composite film layer at the "landing point" of ultraviolet photons vertically incident on the MCP surface, the coating depth needs to be ≥1 / tan(θ), where θ is the bevel angle of the MCP.

[0082] As an example, the process of preparing a composite film layer using atomic layer deposition (ALD) technology mainly includes:

[0083] (1) Prepare MCP with plated electrodes (such as NiCr electrodes). The MCP pore size, bevel angle and size are not limited;

[0084] (2) According to the structure and material property requirements of the composite film layer of the aforementioned embodiment, prepare the selected coating material and the precursor source required for the coating material, such as: lanthanum oxide - La(thd)3+O2, silicon oxide - SiH2(NEt2)2+O3, silicon nitride - SiCl4+NH3, magnesium fluoride - Mg(thd)2+TiF4, etc.;

[0085] (3) The MCP of the film layer to be deposited is placed in a suspended fixture and suspended in the reaction chamber of the ALD equipment, leaving gaps for air flow above and below. The film layer is deposited according to the preset process and composite film layer structure. The total thickness of the composite film layer is controlled in the range of 2nm to 50nm.

[0086] The following describes the implementation of the present invention in more detail with reference to specific examples.

[0087] Embodiment 1:

[0088] Prepare the MCP after NiCr electrode plating: MCP pore size 12 μm, bevel angle 12°, diameter Φ33 mm;

[0089] Prepare silicon oxide, magnesium fluoride and other coating materials, and put the required coating materials into two crucibles of the coating machine, namely crucible one and crucible two;

[0090] Place the MCP in a special fixture that can correct the bevel angle, so that the MCP channel points in the same direction as the MCP rotation axis; place it in the coating machine fixture with the coating angle adjusted so that the coating depth is 8D;

[0091] The film thickness is set to: silicon oxide / magnesium fluoride: 5nm / 30nm.

[0092] Embodiment 2:

[0093] Prepare the MCP after NiCr electrode plating: MCP pore size 12 μm, bevel angle 12°, diameter Φ33 mm;

[0094] Prepare the precursor sources for depositing silicon oxide and magnesium fluoride: silicon oxide - SiH2(NEt2)2+O3, magnesium fluoride - Mg(thd)2+TiF4;

[0095] The MCP of the film layer to be deposited is placed in a suspended fixture and suspended in the reaction chamber of the ALD equipment, leaving airflow gaps above and below to deposit the film layer. The film layer thickness is set to silicon oxide / magnesium fluoride: 5nm / 30nm.

[0096] Embodiment 3:

[0097] Prepare the MCP after NiCr electrode plating: MCP pore size 12 μm, bevel angle 12°, diameter Φ33 mm;

[0098] Prepare the precursor sources for depositing silicon oxide and magnesium fluoride: silicon oxide - SiH2(NEt2)2+O3, magnesium fluoride - Mg(thd)2+TiF4;

[0099] The film layer MCP to be deposited is placed in a special suspension fixture and suspended in the reaction chamber of the ALD equipment, leaving air flow gaps above and below to deposit the film layer. The film layer thickness is set to a silicon oxide / magnesium fluoride stacked structure: (1nm / 6nm)×5.

[0100] On the basis of the above-mentioned Example 1, Example 2, and Example 3, we conducted a comparative test on the ultraviolet light inhibition ratio of the prepared MCP and conventional MCP.

[0101] The MCPs prepared in Example 1, Example 2, and Example 3 are respectively stacked with two conventional MCP sheets to assemble three MCP components, and a single anode is used as the anode type, and an SMA interface is used to lead the anode signal to a data test system;

[0102] Use a signal generator to drive the ultraviolet light source to radiate ultraviolet light, and fix the driving voltage and signal frequency, and use the counting mode to record the number of pulses N1 collected by the MCP to be tested within the time T1;

[0103] Using the same test conditions, the number of pulses N2 collected by the conventional comparison MCP within T2 time was tested;

[0104] The UV response suppression ratio η of the MCP sample to be tested can be calculated as:

[0105] η=(N1·T2) / (N2·T1)

[0106] Wherein, N1 is the number of pulses collected by the MCP to be tested within T1 time; N2 is the number of pulses collected by the conventional MCP within T2 time.

[0107] Table 1 - UV suppression ratio comparison test results

[0108]

[0109] Combined with the above test results, the film thicknesses formed on the MCP input surface of Examples 1, 2 and 3 are similar, but the suppression effect achieved by Example 2 is better than that of Example 1. The main reason is that the physical vapor deposition used in Example 1 does not have the same thickness on the surface and in the channel. The film thickness in the channel is thinner, and the deeper the channel, the thinner the film thickness, and the UV suppression effect is relatively weakened. The magnesium fluoride film layer is prepared on the MCP surface and the inner wall of the channel using ALD technology. The UV suppression effect changes with the thickness of the film layer. Figure 4 As shown, the thicker the film layer, the better the UV light suppression effect.

[0110] Compared with Example 3, Example 2 has a better ultraviolet suppression effect because it has a more tortuous barrier height change, which makes it more difficult for photoelectrons to escape.

[0111] 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 microchannel plate for suppressing ultraviolet light response, characterized in that: include: An array-type electron multiplier composed of millions of mutually parallel channel-type electron multiplying units, each electron multiplying unit forming a microchannel structure; the array-type electron multiplier defines an input surface; and A composite film layer for suppressing ultraviolet light response is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, the composite film layer comprising at least two layers of a first film layer and a second film layer prepared in sequence with high ultraviolet light transmittance and high secondary electron emission coefficient, the first film layer is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, and the second film layer is prepared on the first film layer; Wherein, the bandgap width of the second film layer in the composite film layer is greater than the bandgap width of the first film layer; The coverage of the composite film layer includes the entire input surface and a predetermined depth of the inner wall of the channel of each electron multiplying unit, and the depth range of the composite film layer prepared on the inner wall of the channel of each electron multiplying unit is 3D to 20D, where D is the inner diameter of the channel of the electron multiplying unit.

2. The microchannel plate for suppressing ultraviolet light response according to claim 1, characterized in that: In the composite film layer, the outermost film layer has the highest bandgap width.

3. The microchannel plate for suppressing ultraviolet light response according to claim 1, characterized in that: The composite film layer further includes a third film layer, which is prepared on the second film layer; The bandgap widths of the first film layer, the second film layer and the third film layer show a trend of increasing successively.

4. The microchannel plate for suppressing ultraviolet light response according to claim 1, characterized in that: The material of each film layer of the composite film layer is selected from one of lanthanum oxide, silicon oxide, aluminum oxide, aluminum nitride, silicon nitride, magnesium oxide and magnesium fluoride.

5. The microchannel plate for suppressing ultraviolet light response according to claim 1, characterized in that: For a microchannel plate with a bevel angle of θ, the depth of the composite film layer prepared on the inner wall of the channel of each electron multiplying unit is greater than 1 / tan (θ).

6. The microchannel plate for suppressing ultraviolet light response according to claim 1, characterized in that: The coverage area of ​​the composite film layer includes the entire input surface and the entire through channel inner wall of each electron multiplying unit.

7. The microchannel plate for suppressing ultraviolet light response according to any one of claims 1 to 6, characterized in that: The film thickness of the composite film layer ranges from 2nm to 50nm.

8. A microchannel plate for suppressing ultraviolet light response, characterized in that: include: An array-type electron multiplier composed of millions of mutually parallel channel-type electron multiplying units, each electron multiplying unit forming a microchannel structure; the array-type electron multiplier defines an input surface; and A composite film layer for suppressing ultraviolet light response is prepared on the input surface and the inner wall of the channel of each electron multiplying unit, wherein the composite film layer comprises a multilayer stacked structure formed by regularly stacking at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, wherein the at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient have different bandgap widths; The coverage area of ​​the composite film layer includes the entire input surface and a predetermined depth of the inner wall of the channel of each electron multiplying unit, and the depth range of the composite film layer prepared on the inner wall of the channel of each electron multiplying unit is 3D to 20D, where D is the inner diameter of the channel of the electron multiplying unit.

9. The microchannel plate for suppressing ultraviolet light response according to claim 8, characterized in that: The material of each film layer of the composite film layer is selected from one of lanthanum oxide, silicon oxide, aluminum oxide, aluminum nitride, silicon nitride, magnesium oxide and magnesium fluoride.

10. The microchannel plate for suppressing ultraviolet light response according to claim 8, characterized in that: For a microchannel plate with a bevel angle of θ, the depth of the composite film layer prepared on the inner wall of the channel of each electron multiplying unit is greater than 1 / tan (θ).

11. The microchannel plate for suppressing ultraviolet light response according to claim 8, characterized in that: The coverage area of ​​the composite film layer includes the entire input surface and the entire through channel inner wall of each electron multiplying unit.

12. The microchannel plate for suppressing ultraviolet light response according to any one of claims 8 to 11, characterized in that: The film thickness of the composite film layer ranges from 2nm to 50nm.

13. A method for suppressing ultraviolet light response of a microchannel plate, characterized in that: The following steps are involved: A composite film layer for suppressing ultraviolet light response is prepared on the input surface of an array-type electron multiplier formed by arranging millions of mutually parallel channel-type electron multiplier units and the inner wall of the channel of each electron multiplier unit. The composite film layer is composed of at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, so that a trend of gradually increasing barrier height from the inside to the outside or a trend of fluctuating barrier height is formed between the multiple film layers in the composite film layer, thereby suppressing the escape of photoelectrons excited by ultraviolet light; The coverage area of ​​the composite film layer includes the entire input surface and a predetermined depth of the inner wall of the channel of each electron multiplying unit, and the depth range of the composite film layer prepared on the inner wall of the channel of each electron multiplying unit is 3D to 20D, where D is the inner diameter of the channel of the electron multiplying unit.

14. The method for suppressing ultraviolet light response of a microchannel plate according to claim 13, characterized in that: The composite film layer comprises at least two film layers prepared in sequence and having high ultraviolet light transmittance and high secondary electron emission coefficient, one of which is prepared on the input surface and the inner wall of the channel of each electron multiplication unit, and the outermost film layer has the highest bandgap width; Alternatively, the composite film layer comprises a multilayer stacked structure formed by regularly stacking at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient, wherein the at least two film layers with high ultraviolet light transmittance and high secondary electron emission coefficient have different bandgap widths.

Images