Micro-needle array type gas detector

Abstract

The present application relates to the technical field of gas detector, particularly relates to a microneedle array type gas detector. The microneedle array type gas detector comprises: a cathode plate, one side of the cathode plate is provided with a boss in a central region, which is used as a negative electrode; an anode plate, the anode plate is spaced apart from the cathode plate, and a plurality of microneedles are inserted into one side of the anode plate facing the cathode plate, which is used as a positive electrode; the boss is loaded with a first negative bias, and the microneedle maintains zero potential, which is used to form a drift electric field between the boss and the microneedle. In the present application, the microneedle with large radius of curvature is used as the positive electrode, so that the electric field intensity near the needle tip decreases rapidly with the increase of distance, which can not only make the gas detector operate stably at high gain, but also improve the counting rate performance of the gas detector, and can be flexibly adapted with electronics to expand its dynamic range.

Description

Technical Field

[0001] This invention relates to the field of gas detector technology, and in particular to a microneedle array gas detector. Background Technology

[0002] Particle identification is a crucial aspect of nuclear science and technology, and a common method for screening target nuclear events in nuclear physics experiments. In nuclear fragmentation reactions, to effectively screen for target nuclei from the fragmentation products, a method based on... Methods for identifying charged particles. ΔE gas detectors are typically implemented using structures such as ionization chambers, proportional counters, or time projection chambers, and are used to measure the energy loss of particles in a gas. In environments with ultra-high beam intensity and strong radiation, ΔE gas detectors are required to possess characteristics such as high count rate, wide charge number dynamic range (Z=1~92), and long-life stable operation.

[0003] Conventional ionization chambers collect only raw ionized charges, resulting in small signal amplitude, limited energy resolution, and slow time response, making them unsuitable for high count rate conditions or precise measurement of particle arrival time. While conventional proportional counters obtain higher signals through gas amplification, at high particle fluxes, the signals from multiple anode wires are difficult to accurately correlate to the same track, and crosstalk between wires affects position resolution. Conventional time projection chambers, although capable of identifying multiple particles in a single experiment, often have a dynamic range insufficient to meet the diverse target particle selection requirements of different experiments. Furthermore, they are sensitive to conditions such as magnetic fields, gas purity, temperature, and pressure, posing challenges to operational stability and typically requiring complex calibration systems.

[0004] Therefore, when accurately measuring the energy loss of particles, there is an urgent need for gas detectors that can meet the requirements of high count rate, high gain, and wide dynamic range. Summary of the Invention

[0005] This invention aims to solve the technical problems existing in related technologies. To this end, this invention proposes a microneedle array gas detector to address the issues of limited dynamic range, low operating pressure, and insufficient long-term stability of gas detectors, thereby improving the energy resolution and expanding the dynamic range of the gas detector to be suitable for screening a variety of target particles.

[0006] This invention provides a microneedle array gas detector, comprising:

[0007] A cathode plate, wherein a boss is provided on one side of the cathode plate in the central region for use as a cathode electrode;

[0008] An anode plate is provided, which is spaced apart from the cathode plate. Several microneedles are inserted into the side of the anode plate facing the cathode plate to serve as anode electrodes.

[0009] The boss is subjected to a first negative bias voltage, and the microneedle is kept at zero potential, which is used to form a drift electric field between the boss and the microneedle.

[0010] According to the present invention, a microneedle array gas detector further includes a gate, which is disposed parallel between the anode plate and the cathode plate. The gate is loaded with a second negative bias voltage, the absolute value of which is less than the absolute value of the first negative bias voltage, to suppress the positive ion movement of the drift electric field from generating an induction signal on the microneedle.

[0011] According to the present invention, a microneedle array gas detector is provided, wherein the gate and the protrusion are spaced apart by a first distance to form a drift region, and the gate and the tip of the microneedle are spaced apart by a second distance to form a collection region, and the output signal of the microneedle originates from the drift motion of electrons in the collection region.

[0012] A microneedle array gas detector according to the present invention further includes:

[0013] The voltage equalizing electrode is configured as a metal ring with a through hole in the center, and a resistor is connected in series between the voltage equalizing electrode and the gate.

[0014] The equalizing electrode is located between the gate and the cathode plate, and the central axis of the through hole of the equalizing electrode coincides with the central axis of the boss.

[0015] According to a microneedle array gas detector provided by the present invention, a plurality of equalizing electrodes are arranged in parallel and spaced apart between the gate and the cathode plate, and a resistor is connected in series between adjacent equalizing electrodes to make the potential of the drift region change in a gradient.

[0016] According to the present invention, a number of microneedles are arranged in an equilateral triangular lattice to form a positive electrode coverage area with a polygonal outer perimeter on the anode plate. The diameter of the outer circle of the positive electrode coverage area is smaller than the diameter of the boss.

[0017] According to a microneedle array gas detector provided by the present invention, a parallel circuit is provided on the first side of the anode plate, and the parallel circuit is connected to each of the microneedles to output a sum signal.

[0018] According to the present invention, each microneedle array gas detector is provided with a pin on the second side of the anode plate for independently outputting a signal.

[0019] According to the present invention, a microneedle array gas detector is provided, wherein the diameter of the microneedles is between 0.1 mm and 1 mm, the height of the microneedles protruding from the surface of the anode plate is between 1 mm and 3 mm, and the spacing between adjacent microneedles is 8 mm.

[0020] According to the present invention, a microneedle array gas detector is provided, wherein the gate comprises:

[0021] The PCB frame is configured as a ring, and the diameter of the inner peripheral edge of the PCB frame is larger than the diameter of the boss.

[0022] The wire mesh is installed at the annular holes of the PCB frame.

[0023] The above-described one or more technical solutions of this invention have at least one of the following technical effects:

[0024] In this invention, the microneedle array gas detector uses microneedles with a large radius of curvature as the anode, which causes the electric field strength near the needle tip to decrease rapidly with increasing distance. This can significantly reduce the risk of discharge and aging effect, thereby enabling the gas detector to operate stably at high gain and under high pressure conditions. This helps to improve the counting rate performance and can also be flexibly adapted to electronics to expand its dynamic range.

[0025] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted by the present invention, and the advantages brought about by the technical features of these technical solutions as described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings, or will be learned through the practice of the present invention. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a microneedle array gas detector provided in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of microneedles arranged in an equilateral triangular lattice on an anode plate, as provided in an embodiment of the present invention.

[0029] Figure 3 This is a front view of the anode plate provided in an embodiment of the present invention.

[0030] Figure label:

[0031] 10. Cathode plate; 11. Boss; 20. Anode plate; 21. Microneedle; 30. Gate; 31. PCB frame; 32. Silk screen; 40. Equalizing electrode; 50. Resistor. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0033] In the existing technology, based on In charged particle identification methods, ΔE gas detectors often face problems such as limited dynamic range, low operating pressure, and insufficient stability at high count rates: conventional ionization chambers have small signal amplitude and poor energy resolution; conventional proportional counters have inter-filament crosstalk; conventional time projection chambers are sensitive to environmental conditions and have complex calibration, making it difficult to meet the requirements of ultra-high beam intensity, wide charge number dynamic range (Z=1~92), and long-life stable operation.

[0034] To address the aforementioned challenges, an embodiment of the present invention introduces a microneedle array gas detector.

[0035] like Figure 1 As shown, the microneedle array gas detector mainly includes a cathode plate 10 and an anode plate 20.

[0036] A protrusion 11 is provided on one side of the cathode plate 10 in the central region, which serves as a negative electrode. The anode plate 20 is disposed at a distance from the cathode plate 10. A plurality of microneedles 21 are inserted into the side of the anode plate 20 facing the cathode plate 10, which serve as positive electrodes.

[0037] Specifically, the anode plate 20 and the cathode plate 10 are arranged parallel to each other along the vertical direction of the plate surface. The microneedles 21 protrude towards the first side of the anode plate 20. Furthermore, the microneedles 21 are opposite to the boss 11.

[0038] The boss 11 is loaded with a first negative bias voltage, and the microneedle 21 is kept at zero potential, which is used to form a drift electric field between the boss 11 and the microneedle 21.

[0039] Specifically, both the cathode plate 10 and the anode plate 20 are made of PCB board.

[0040] The cathode region on the cathode plate 10 is the area where the boss 11 is located. The boss 11 is cylindrical with a cross-sectional diameter of 115 mm. Several microneedles 21 are inserted into the anode plate 20. These microneedles 21 together serve as the anode opposite the boss 11.

[0041] In operation, the microneedle 21 is typically grounded to maintain zero potential, and the boss 11 is loaded with a first negative bias voltage, thereby forming a drift electric field between the boss 11 loaded with negative high voltage and the grounded microneedle 21.

[0042] Furthermore, to optimize signal quality, the microneedle array gas detector also includes a gate 30. The gate 30 is disposed parallel between the anode plate 20 and the cathode plate 10.

[0043] The gate 30 is loaded with a second negative bias voltage. The absolute value of the second negative bias voltage is less than the absolute value of the first negative bias voltage, which is used to suppress the positive ion movement of the drift electric field from generating an induction signal on the microneedle 21.

[0044] The gate 30 is spaced apart from the protrusion 11 by a first distance to form a drift region, and the gate 30 is spaced apart from the tip of the microneedle 21 by a second distance to form a collection region. The output signal of the microneedle 21 originates from the drift motion of electrons within the collection region.

[0045] Preferably, the first distance is 68 mm and the second distance is 15.7 mm. The gate 30 is spaced 15.7 mm from the tip of the microneedle 21 to form a collection region. The gate 30 is spaced 68 mm from the protrusion 11 to form a drift region.

[0046] Specifically, the gate 30 includes a PCB frame 31 and a screen 32.

[0047] The PCB frame 31 is circular. The screen 32 is installed at the annular holes of the PCB frame 31. The PCB frame provides stable mechanical support, keeping the screen 32 flat and preventing uneven electric field caused by slack in the screen 32.

[0048] The wire mesh 32 is made of 400-mesh stainless steel wire mesh 32. The 400-mesh stainless steel wire mesh has both good conductivity and air permeability, which can ensure the electrostatic shielding effect of the grid 30 without affecting gas flow and electron drift.

[0049] The diameter of the inner peripheral edge of the PCB frame 31 is larger than the diameter of the boss 11 to ensure that drifting electrons can pass smoothly through the annular hole of the PCB frame 31.

[0050] The main function of the gate 30 is to act as an electrostatic shield, thereby dividing the inside of the detector into two regions: the drift region between the gate 30 and the boss 11; and the collection region between the gate 30 and the tip of the microneedle 21.

[0051] The gate 30 can effectively suppress the induced signal generated on the microneedle 21 by the movement of positive ions in the drift region, ensuring that the signal output by the microneedle 21 mainly comes from the drift and avalanche movement of electrons in the collection region, thereby improving the signal-to-noise ratio and time response speed.

[0052] Unlike traditional planar electrodes, the electric field strength near the tip of the microneedle 21 decreases rapidly with increasing distance, approximately inversely proportional to the distance. This confines the electron avalanche multiplication process to an extremely small micro-region (micrometer scale) near the tip of each microneedle 21. As the distance increases, the electric field rapidly transitions to a uniform electric field in the drift region. This design keeps the amplification region away from the surface of the insulating medium, making the gain insensitive to charge accumulation on the medium surface. This significantly reduces the risk of discharge and aging effects, enabling the gas detector to operate stably for extended periods under high-gain conditions, making it particularly suitable for experimental environments with high beam current.

[0053] In this embodiment, the microneedle array gas detector uses microneedles 21 with a large radius of curvature as the anode, so that the electric field strength near the needle tip decreases rapidly with increasing distance. This can significantly reduce the risk of discharge and aging effect, thereby enabling the gas detector to operate stably under high gain and under high pressure conditions. This helps to improve the counting rate performance and can also be flexibly adapted to electronics to expand its dynamic range.

[0054] Based on the above embodiments, another embodiment of the present invention introduces a microneedle array gas detector.

[0055] To ensure the uniformity of the electric field within the drift region, the microneedle array gas detector also includes an equalizing electrode 40.

[0056] The equalizing electrode 40 is configured as a metal ring with a central through hole. A resistor 50 is connected in series between the equalizing electrode 40 and the gate 30. The equalizing electrode 40 is located between the gate 30 and the cathode plate 10. Furthermore, the central axis of the through hole of the equalizing electrode 40 coincides with the central axis of the boss 11.

[0057] Preferably, the equalizing electrode 40 is made of oxygen-free copper. The equalizing electrode 40 is configured as an annular plate with a thickness of 2 mm.

[0058] Furthermore, a plurality of equalizing electrodes 40 are arranged in parallel and spaced apart between the gate 30 and the cathode plate 10. Adjacent equalizing electrodes 40 are connected in series via resistors 50 to create a potential gradient in the drift region.

[0059] Specifically, several equalizing electrodes 40 are arranged at intervals along the central axis of the protrusion 11. Adjacent equalizing electrodes 40 are connected in series through resistors 50. By dividing the voltage in series, the potential of the drift region changes linearly along the axial direction, thereby creating a highly uniform drift electric field between the cathode plate 10 and the anode plate 20. This can guide the electrons generated by ionization to drift towards the anode plate 20, reducing the lateral diffusion and recombination loss of electrons during the drift process.

[0060] Preferably, the resistor 50 connected in series between adjacent equalizing electrodes 40 has a resistance of 3MΩ.

[0061] Based on the above embodiments, another embodiment of the present invention introduces a microneedle array gas detector.

[0062] like Figure 2 As shown, a plurality of microneedles 21 are arranged in an equilateral triangular lattice to form a positive electrode coverage area with a polygonal outer perimeter on the anode plate 20. The diameter of the outer circle of the positive electrode coverage area is smaller than the diameter of the boss 11.

[0063] Preferably, in order to effectively avoid mutual interference of electric fields between microneedles 21, and at the same time ensure that there is sufficient microneedle density on the anode plate to balance position resolution and signal independence, the spacing between adjacent microneedles 21 is 8 mm.

[0064] The number of microneedles 21 can be set as needed. For example, 199 microneedles 21 can be arranged on the anode plate 20 to form a dodecagonal anode coverage area. The outer diameter of the circumscribed circle of the anode coverage area is approximately 120 mm and is adapted to the boss 11.

[0065] Furthermore, since the size of the microneedle 21 can have a significant impact on the drift electric field: the diameter of the microneedle 21 is between 0.1 mm and 1 mm, and the height of the microneedle 21 protruding from the surface of the anode plate 20 is between 1 mm and 3 mm.

[0066] Preferably, the diameter of the microneedle 21 is set to 0.3 mm, and the height of the microneedle 21 protruding from the surface of the anode plate 20 is set to 1.3 mm.

[0067] The microneedle 21 is fixed through the metallized positioning hole on the anode plate 20, and can be electrically and mechanically connected to the back of the plate by brazing.

[0068] Furthermore, the microneedle array gas detector in this invention is designed with two signal readout methods:

[0069] The first type is the summation signal mode. A parallel line is provided on the first side of the anode plate 20. The parallel line is connected to each of the microneedles 21 so as to output a summation signal.

[0070] The second type is the individual signal mode, in which each of the microneedles 21 is provided with a pin on the second side of the anode plate 20 for independent signal output.

[0071] Furthermore, the microneedle array gas detector can adapt to a wide range of gas pressure conditions. Specifically, the microneedle array gas detector supports two operating modes: a flow mode at normal pressure and a static sealing mode at high pressure (10 standard atmospheres, approximately 1 MPa).

[0072] During testing, the assembled microneedle array gas detector is installed in a sealed aluminum alloy chamber to ensure good electromagnetic shielding and mechanical stability.

[0073] The sealed aluminum alloy chamber is equipped with a high-pressure interface, a low-pressure interface, a signal interface, and an air inlet and outlet. The working gas is P10 gas, which is 90% Ar + 10% CH4.

[0074] Due to the unique electric field distribution of the microneedle array, the microneedle array gas detector can maintain a high gas gain and is not prone to breakdown even under high gas pressure. High gas pressure can significantly increase the density of the gas medium, thereby improving the detection efficiency of the microneedle array gas detector for high-energy particles or weakly ionized particles, and also increasing the upper limit of the count rate of the microneedle array gas detector.

[0075] The working principle of a microneedle array gas detector is as follows: When charged particles pass through the drift region, they ionize the working gas, generating electron-ion pairs. Under the uniform electric field formed by the equalizing electrode 40, the initially ionized electrons drift towards the anode plate 20. After passing through the grid 30 and entering the collection region, the electrons continue to move towards the microneedles 21. When the electrons reach the strong electric field region near the tip of the microneedle 21, electron avalanche multiplication occurs. Finally, the induced charge signal is extracted through the microneedles 21 and read and analyzed by a charge-sensitive preamplifier (such as ORTEC142PC). By adjusting the negative high voltage applied to the cathode, the negative bias voltage applied to the grid 30, and the gain level of the back-end electronics, the operating region of this detector can flexibly cover from the ionization region to the proportional region, achieving an extremely wide charge number dynamic range (Z=1~92).

[0076] The microneedle array gas detector of this invention has the following advantages: 1. Stable electric field distribution, with the amplification region far from the dielectric surface, making the gain insensitive to charge accumulation on the dielectric surface and enabling stable operation at high gain; 2. Support for high-pressure operation and strong adaptability: The unique electric field distribution of the microneedle array enables the detector to operate under high-pressure conditions, which helps to improve the count rate performance and obtain the required gain and detection efficiency under high-pressure conditions when detecting low-energy particles; 3. Wide dynamic range, with the working area covering the ionization region to the proportional region; flexible adaptation to electronics, and can be used with front-end electronics systems with adjustable gain levels to further expand its dynamic range and environmental adaptability.

[0077] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of 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. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0078] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0079] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms are not limited to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microneedle array gas detector, characterized in that, include: A cathode plate (10) has a boss (11) on one side in the central region, which serves as a cathode electrode; An anode plate (20) is provided at intervals with the cathode plate (10). A plurality of microneedles (21) are inserted on the side of the anode plate (20) facing the cathode plate (10) to serve as anode electrodes. The microneedle (21) protrudes toward the first side of the anode plate (20) and is opposite to the boss (11). The boss (11) is loaded with a first negative bias voltage, and the microneedle (21) is kept at zero potential to form a drift electric field between the boss (11) and the microneedle (21). It also includes a gate (30), which is disposed in parallel between the anode plate (20) and the cathode plate (10). The gate (30) is loaded with a second negative bias voltage, the absolute value of which is less than the absolute value of the first negative bias voltage, in order to suppress the positive ion movement of the drift electric field from generating an induction signal on the microneedle (21). The gate (30) and the boss (11) are spaced apart by a first distance to form a drift region, and the gate (30) and the top of the microneedle (21) are spaced apart by a second distance to form a collection region. The output signal of the microneedle (21) comes from the drift motion of electrons in the collection region.

2. The microneedle array gas detector according to claim 1, characterized in that, Also includes: The equalizing electrode (40) is configured as a metal ring with a through hole in the center, and a resistor (50) is connected in series between the equalizing electrode (40) and the gate (30). The equalizing electrode (40) is located between the gate (30) and the cathode plate (10), and the central axis of the through hole of the equalizing electrode (40) coincides with the central axis of the boss (11).

3. The microneedle array gas detector according to claim 2, characterized in that, A plurality of equalizing electrodes (40) are arranged in parallel and spaced apart between the gate (30) and the cathode plate (10), and a resistor (50) is connected in series between adjacent equalizing electrodes (40) to make the potential of the drift region change in a gradient.

4. The microneedle array gas detector according to claim 3, characterized in that, Several microneedles (21) are arranged in an equilateral triangle lattice to form a positive electrode covering area with a polygonal outer perimeter on the anode plate (20). The outer circle diameter of the positive electrode covering area is smaller than the diameter of the boss (11).

5. The microneedle array gas detector according to claim 4, characterized in that, A parallel line is provided on the first side of the anode plate (20), and the parallel line is connected to each of the microneedles (21) so as to output a sum signal.

6. The microneedle array gas detector according to claim 4, characterized in that, Each of the microneedles (21) has a pin on the second side of the anode plate (20) for independently outputting a signal.

7. The microneedle array gas detector according to claim 4, characterized in that, The diameter of the microneedle (21) is between 0.1 mm and 1 mm, the height of the microneedle (21) protruding from the surface of the anode plate (20) is between 1 mm and 3 mm, and the distance between adjacent microneedles (21) is 8 mm.

8. The microneedle array gas detector according to claim 2, characterized in that, The gate (30) includes: The PCB frame (31) is set as a ring, and the diameter of the inner peripheral edge of the PCB frame (31) is greater than the diameter of the boss (11); A wire mesh (32) is installed at the annular holes of the PCB frame (31).

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