Delay line position sensitive detector and method of detecting

Abstract

The application provides a time delay line position sensitive detector and a detection method thereof, and relates to the technical field of ion detectors and vacuum electronics. The detector comprises a microchannel plate assembly, a delay line anode plate, a first grid and a second grid arranged in a vacuum space in sequence, and a control unit. The control unit applies a positive bias voltage to the first grid to establish a longitudinal extraction acceleration electric field, applies a bias voltage to the second grid to establish a uniform drift electric field, and the two layers of grids physically intercept the large-angle outgoing electron flow by using the entity of the two layers of grids to shield part of the two layers of grids. The application cooperates the multi-layer electric field segmentation and the grid physical shielding to forcibly compress the electron outgoing angle and inhibit the transverse diffusion, significantly reduces the time dispersion, limits the anode projection radius in a small range, effectively solves the contradiction between the high spatial resolution and the vacuum breakdown risk, and meets the analysis demand of complex component instantaneous full polarity switching.

Description

Technical Field

[0001] This invention relates to the field of ion detectors and vacuum electronics technology, and more specifically, to a time-delay linear position-sensitive detector and its detection method. Background Technology

[0002] A delay line detector (DLP) is a two-dimensional particle or photon detection system used for high-precision position and time measurement. It combines the gain capability of a microchannel plate with the position decoding capability of delay line technology, making it a key device in modern scientific experiments for achieving high spatiotemporal resolution imaging and counting. The core working principle of a DLP is to convert the spatial position information of a particle or photon into the time difference information of an electrical signal transmitted along a transmission line for measurement. Specifically, an incident particle impacts the microchannel plate at the front of the detector, exciting secondary electrons, which are multiplied multiple times within the microchannel plate to form a charge cloud. This amplified charge cloud is collected by the delay line anode, inducing a transient current on the anode. This current pulse propagates to both ends of the delay line. The system calculates the location of the event by accurately recording the time difference of the pulse's arrival at both ends, and obtains the event's occurrence time by summing the arrival times. Currently available delay line anode technologies mainly include spiral-wound anodes, multilayer integrated anodes, and cross-delay line anodes. Spiral wound anode technology is mature and has a wide field of view, but the manufacturing process is extremely dependent on manual labor, has poor vibration resistance, and is prone to thermal drift; multi-layer integrated anode structure is stable and suitable for industrial mass production, but has extremely high requirements for dielectric loss; cross-delay line anode has extremely high spatial resolution and excellent vacuum compatibility, but the large overlap area between electrodes leads to serious parasitic capacitance problems.

[0003] However, existing technologies face a core bottleneck that severely limits detection accuracy in practical applications. When a particle enters the microchannel plate and triggers secondary electron multiplication, the time elapsed from particle incidence to the peak value of the output pulse is called the transit time. In existing designs, due to differences in the initial incident angle of the ions, the transit time dispersion is typically as high as 50 to 100 picoseconds or even higher, directly introducing significant background fluctuations for high-precision time measurements. Simultaneously, the electron cloud emitted from the microchannel plate rapidly expands in the drift region towards the anode due to different emission angle distributions and strong space charge effects and Coulomb repulsion. This lateral expansion not only causes a severe shift in the center of mass of the electron cloud, distorting the position coordinates of the received signal, but also further exacerbates the non-negligible time distortion and dispersion due to the significant geometrical flight path difference between electrons at large emission angles and those on the central axis. To suppress the spatial dispersion of the electron cloud, traditional solutions often force a significant reduction in the physical distance between the microchannel plate and the anode. However, in actual high-voltage operating environments, this can easily lead to excessive local field strength, resulting in tip discharge or vacuum breakdown, creating an irreconcilable contradiction between the requirements of high spatial resolution and high-voltage operational stability. Furthermore, in scenarios involving rapid switching between positive and negative ions in all-polarity analysis, the insulating dielectric layer between the microchannel plate and the anode easily accumulates residual charge, generating a charge memory effect. This causes severe baseline drift in the system, significantly impacting the dynamic response capability and data reliability during rapid analysis of complex components. Summary of the Invention

[0004] The present invention aims to solve at least one of the aforementioned technical problems existing in the prior art.

[0005] Therefore, in a first aspect, the present invention provides a time-delayed linear position-sensitive detector.

[0006] A second aspect of the present invention provides a detection method for a time-delay linear position-sensitive detector.

[0007] The present invention provides a time-delay linear position-sensitive detector, comprising: Microchannel plate assembly for receiving incident particles and outputting a multiplied electron cloud; A delay line anode plate, disposed at the rear end of the microchannel plate assembly, is used to sense the electron cloud and generate position and time signals; A first grid and a second grid are sequentially disposed in the vacuum space between the microchannel plate assembly and the delay line anode plate, wherein the first grid is disposed near the output end of the microchannel plate assembly and the second grid is disposed near the delay line anode plate; A control unit, connected to the first grid and the second grid respectively, is used to apply an independently adjustable potential bias to the first grid and the second grid; The first grid is configured to apply a positive bias voltage higher than the output potential of the microchannel plate assembly to establish a longitudinal accelerating electric field between the microchannel plate assembly and the first grid, thereby forcibly compressing the electron emission angle. The second grid is configured to apply a bias voltage with a potential difference from the delay line anode plate within a set range to establish a uniform drift electric field between the first grid and the second grid, thereby eliminating electric field edge distortion and spatially focusing the electron cloud; and the first grid and the second grid use the physical shielding portion of their own metal mesh to physically block the electron flow emitted at a large angle.

[0008] The time-delay linear position-sensitive detector according to the above-described technical solution of the present invention may also have the following additional technical features: In the above technical solution, the control unit has an all-polarity zeroing mode, which is configured to apply alternating depolarization pulses to the first grid and the second grid during the interval when the delay line position-sensitive detector switches between positive and negative polarities, so as to use the first grid and the second grid as active suction poles to induce and discharge the residual charge on the surface and in the space of the delay line anode plate.

[0009] In the above technical solution, the delay line anode plate includes a surface layer and a metal shielding ground layer disposed below the surface layer. The surface layer is provided with delay line anodes, and the metal shielding ground layer is only perforated at the node positions corresponding to the delay line anodes to isolate parasitic capacitive coupling between nodes.

[0010] In the above technical solution, the microchannel plate assembly includes a first microchannel plate and a second microchannel plate stacked along the direction of electron movement. A grid electrode is provided in front of the input end of the first microchannel plate. The microchannel plate assembly, the first grid, the second grid, and the delay line anode plate are all isolated and supported by insulating pads, and are mechanically positioned by ceramic support rings on the periphery.

[0011] In the above technical solution, both the first grid and the second grid are metal honeycomb meshes with a transmittance greater than 81% and a mesh count of 100 to 300. And / or, the positive bias voltage of the first grid is 100V to 800V higher than the output potential of the microchannel plate assembly.

[0012] In the above technical solution, the distance between the first grid and the output end of the microchannel plate assembly is 0.3mm to 1.5mm; And / or, the spacing between the first grid and the second grid is 0.5 mm to 3.0 mm; And / or, the distance between the second grid and the delay line anode plate is 0.2 mm to 1.5 mm.

[0013] This invention provides a detection method for a time-delay linear position-sensitive detector, which performs detection based on a time-delay linear position-sensitive detector as described in any of the above technical solutions. The method includes: The microchannel plate assembly multiplies the output electron cloud; The control unit applies a positive bias voltage to the first grid to establish a longitudinal accelerating electric field, forcing the electron cloud to accelerate and collimate longitudinally before lateral diffusion; The control unit applies a bias voltage to the second grid to flatten the spatial electric field above the delay line anode plate, so that the collimated electron cloud passes through the second grid at a constant speed. By utilizing the physical grid structure of the first and second grids, an electron stream that still has a large exit angle after passing through the longitudinal accelerating electric field is intercepted; The electron cloud vertically impacts the delay line anode plate to generate a differential signal.

[0014] In the above technical solution, when the delay line position-sensitive detector switches between positive and negative polarities, during the gap before switching from the first polarity detection to the second polarity detection, the control unit simultaneously applies alternating depolarization pulses to the first grid and the second grid, so as to release the residual charge on the surface and in the space of the delay line anode plate through the first grid and the second grid as active charge suction electrodes.

[0015] In the above technical solution, by adjusting the potential difference between the first grid and the second grid to a set threshold, an electrostatic lens effect is generated between the first grid and the second grid, thereby performing secondary contraction and focusing on the electron beam flying toward the delay line anode plate.

[0016] In the above technical solution, the potential amplitude range of the alternating depolarization pulse is 300V to 600V, and the frequency range is 5kHz to 20kHz.

[0017] In summary, due to the adoption of the above-mentioned technical features, the beneficial effects of the present invention are: This invention provides a time-delay linear position-sensitive detector and its detection method. By introducing a double-layer metal grid structure with a specific bias state and physical topology between the output end of a microchannel plate and the anode of the delay line, significant technical effects are achieved in terms of time resolution, spatial resolution, and system operational stability. This invention establishes a longitudinal accelerating electric field by setting a first grid and, in conjunction with a second grid, establishes a uniform drift electric field, forcibly canceling the lateral velocity component of the electron cloud emitted from the microchannel plate, making the longitudinal velocity components of electrons at different emission angles tend to be consistent. This path normalization mechanism effectively reduces the time dispersion caused by the emission angle distribution from the original 50-100 picoseconds to about 10 picoseconds. Simultaneously, the collimated electron cloud synchronously impacts the anode, resulting in a sharper rising edge of the generated induced pulse signal, reducing the amplitude aliasing error of the path discrimination circuit, and contributing to the achievement of 10 picosecond resolution. 5 The above-mentioned high-quality resolution provides a physical foundation. Regarding spatial resolution, this invention utilizes the spatial electric field above the anode, flattened by a second grid, to eliminate edge electric field distortion. Combined with the physical interception effect of the double-layer metal grid on electron beams with large emission angles, it achieves precise contraction of the electron beam. This structure can compress the lateral expansion radius of the electron cloud upon reaching the anode by more than 60%, strictly limiting its projected radius to within 50 micrometers. This not only improves the weight accuracy of the centroid algorithm but also solves the problem of crosstalk between adjacent nodes caused by an excessively large electron cloud, enabling the equivalent spatial resolution to steadily reach the micrometer level.

[0018] This invention introduces a multi-layered grid as an electric field relay structure, dividing the single large-gap high-voltage field between the microchannel plate and the anode into multiple low-voltage controlled fields. This field segmentation design, without reducing the anode induction intensity, allows the overall physical distance between the microchannel plate assembly and the delay line anode plate to be increased by 2 to 4 times compared to traditional designs. This breakthrough in large spacing effectively suppresses tip discharge, micro-discharge, and baseline noise caused by field emission, greatly reducing the risk of vacuum breakdown and providing hardware-level assurance for the long-term high-voltage stability of the detector in harsh vacuum environments. Simultaneously, the grid with bias voltage also acts as an ion baffle, intercepting reverse positive ions excited from the anode surface, preventing them from returning to the microchannel plate and generating secondary spurious signals, thus purifying the spectral baseline. Furthermore, the control unit in this invention features an all-polarity zeroing mode. During the transition between positive and negative ion detection modes, the multi-layered grid acts as an active charge-drawing electrode, receiving alternating depolarization pulses, which can clear residual space charge in the drift region and induce the removal of charge deposited on the anode surface within milliseconds. This active polarity recovery mechanism overcomes the charge residue limitation of the anode insulating layer in traditional detectors, avoids mode switching lag, and achieves transient full polarity switching, meeting the hardware requirements for rapid analysis of complex components. Compared to the traditional design that is close to the microchannel plate, the grid structure of this invention also improves the heat dissipation of the microenvironment in the anode region, reduces the delay line impedance drift caused by local temperature rise at high count rates, and ensures the performance consistency of the detector under long-term continuous operation.

[0019] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a time-delay linear position-sensitive detector according to an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the effect of a time-delayed linear position-sensitive detector according to an embodiment of the present invention on eliminating large-angle emitted electron clouds; Figure 3 This is a flowchart illustrating the detection method of a time-delay linear position-sensitive detector according to an embodiment of the present invention.

[0021] in, Figures 1 to 3 The correspondence between the reference numerals and component names in the attached drawings is as follows: 1. Grid electrode; 2. Insulating gasket; 3. Metal gasket; 4. First microchannel plate; 5. Second microchannel plate; 6. First grid; 7. Second grid; 8. Delay line anode plate. Detailed Implementation

[0022] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0024] The following reference Figures 1 to 3 This invention describes a time-delay linear position-sensitive detector and its detection method provided according to some embodiments of the present invention.

[0025] Some embodiments of this application provide a time-delay linear position-sensitive detector.

[0026] This invention addresses the transit time discrepancies and positional deviations caused by the lateral diffusion of electron clouds, space charge effects, and large emission angles in traditional time-delay linear position-sensitive detectors. It breaks away from the inherent bias of sacrificing voltage stability by drastically compressing the gap between the microchannel plate and the anode. By introducing a multi-layer cooperative grid system independently controlled by a control unit into the vacuum space between the microchannel plate output and the delay line anode, the original single high-voltage gap is divided into multiple low-voltage-drop controlled regions. Furthermore, by organically combining electric field dynamic collimation, electrostatic lens focusing, and grid geometrical occlusion, the invention achieves dual synchronous compression of the electron cloud in both the time and spatial dimensions.

[0027] Combination Figure 1 As shown, this embodiment provides a time-delay line position-sensitive detector, whose overall hardware topology includes a microchannel plate assembly, a delay line anode plate 8 disposed at the rear end of the microchannel plate assembly, a first grid 6 and a second grid 7 disposed sequentially in the vacuum space between the microchannel plate assembly and the delay line anode plate 8, and a control unit respectively connected to the first grid 6 and the second grid 7.

[0028] The microchannel plate assembly receives incident particles and outputs a multiplied charge cloud; the delay line anode plate 8 senses the electron cloud and generates a high-precision position and time signal. The first grid 6 is positioned near the output end of the microchannel plate assembly, and the second grid 7 is positioned near the delay line anode plate 8. The control unit independently adjusts the potential bias of each grid layer. The first grid 6 is configured to apply a positive bias voltage higher than the output potential of the microchannel plate assembly, thereby constructing a strong longitudinal extraction and acceleration electric field between the output of the microchannel plate assembly and the first grid 6. This forces the compression of the electron emission angle, causing oblique electrons to transform into direct electrons, significantly shortening the geometric flight path of large-angle electrons, and thus suppressing time dispersion caused by path difference. The second grid 7 is configured to apply a bias voltage with a potential difference from the delay line anode plate 8 within a set range (the induced potential of the second grid 7 and the delay line anode plate 8 should be as close as possible or equal), thereby establishing a uniform drift electric field between the first grid 6 and the second grid 7 to eliminate electric field edge distortion and edge effects of the microchannel plate channel walls, and to spatially focus the electron cloud. Meanwhile, both the first grid 6 and the second grid 7 are metal grids with specific specifications. The physical blocking part of the grid is used to physically block the inclined electron flow that still exceeds the set value after passing through the lead-in field, so as to reduce its throughput and ensure that the electron cloud projection radius that finally reaches the anode surface is precisely limited.

[0029] In some embodiments, to ensure the mechanical stability and insulation reliability of the detector under high-voltage operating conditions, the time-delay linear position-sensitive detector adopts a multi-layer sandwich compact hardware topology, and the diameter of its effective detection area is not less than 50 mm. Combined with... Figure 1 As shown, the microchannel plate assembly includes a first microchannel plate 4 and a second microchannel plate 5 stacked along the electron motion direction, providing high charge gain capability through a double-layer stacked design. A grid electrode 1 is disposed in front of the input end of the first microchannel plate 4 to establish a uniform incident reference field or for electromagnetic shielding. The physical spacing between the microchannel plate assembly, the first grid 6, the second grid 7, and the delay line anode plate 8 is precisely isolated and supported by precision insulating gaskets 2 (such as Teflon gaskets) and metal gaskets 3. The periphery of the overall structure uses a high-insulation, low-emission ceramic support ring, such as 99% alumina ceramic, for mechanical positioning and fastening. In addition, compared with the traditional dense design where the anode is tightly attached to the microchannel plate, the multi-layer gasket and grid isolation support structure adopted in this invention significantly improves the heat dissipation of the microenvironment in the anode area, reduces the delay line impedance drift caused by local temperature rise under high count rates, and ensures the consistency of the detector's electrical performance during long-term continuous operation.

[0030] In one specific embodiment, the physical spacing parameters between key components are optimized to eliminate the risk of tip discharge while ensuring a strong field strength. Specifically, the physical spacing between the first grid 6 and the output end of the microchannel plate assembly is set to 0.3mm to 1.5mm, preferably 0.8mm; the physical spacing between the first grid 6 and the second grid 7 is set to 0.5mm to 3.0mm, preferably 1.5mm, thereby constructing a stable uniform-strength drift region; the physical spacing between the second grid 7 and the delay line anode plate 8 is set to 0.2mm to 1.5mm, preferably 0.5mm. Through the above-mentioned large-spacing field segmentation design, without reducing the induced field strength of the delay line anode plate, the overall physical spacing between the microchannel plate assembly and the delay line anode plate can be increased by 2 to 4 times compared to the traditional compact design. This design enables the detector to maintain extremely high operating voltage stability and long-term vacuum breakdown reliability even when a kilovolt-level operating voltage is applied.

[0031] In some embodiments, in order to minimize obstruction and moiré interference to the effective electron beam while achieving efficient physical collimation, the structural materials and physical specifications of the first grid 6 and the second grid 7 are subject to specific parameter limitations. Both the first grid 6 and the second grid 7 are made of high-transmittance metal honeycomb mesh, with an overall transmittance greater than 81%, and a mesh size maintained between 100 and 300 meshes. The preferred materials are nickel or molybdenum meshes.

[0032] In terms of electrical parameter configuration, the control unit implements independent dynamic control of each layer. The positive bias voltage applied to the first grid 6 is 100V to 800V higher than the output potential of the microchannel plate assembly. In a preferred embodiment, this potential difference is maintained at 200V. This high potential gradient forces the electrons with large lateral velocity escaping from the microchannel plate holes to be rapidly accelerated in the positive z-axis direction, reducing the influence of the lateral velocity on the total flight time to a second-order infinitesimal, and compressing the time dispersion caused by the emission angle to within 10ps; combined with Figure 2As shown, this physical grid structure with a specific thickness and aperture ratio exhibits a unique three-dimensional shielding mechanism. When the incident angle between electrons and the grid electrode is α, the mesh width is D, and the diameter of the grid winding is d, the throughput of the electron cloud emitted at a large angle decreases from (Dd) / D in the orthogonal state to (Dsinα-2d) / Dsinα, thereby forcibly intercepting the electron flow whose emission angle still exceeds the set value at the geometric level. The bias voltage of the second grid 7 is controlled to be very close to the surface induced potential of the delay line anode plate 8, placing it within the set potential difference range, thereby establishing a distortion-free reference plane for the collimated electron beam to pass through at a uniform speed. At the same time, the grid under a specific bias voltage state also acts as an ion baffle in this topology. This electric field distribution can effectively intercept the reverse positive ions excited from the surface of the delay line anode plate, preventing them from flying back into the microchannel plate and generating secondary pseudo-signals. From a hardware physical mechanism perspective, this purifies the baseline of the detection spectrum and improves the overall dynamic range of the system.

[0033] In one specific embodiment, to further improve spatial resolution and eliminate signal aliasing, the delay line anode plate 8 undergoes specific optimization in its electronic readout structure. The delay line anode plate 8 employs a multilayer low-loss integrated circuit board structure, such as the Rogers series high-frequency microwave board, which includes a surface layer for exciting picosecond-level differential electrical signals and a metal shielding ground layer disposed beneath the surface layer. Delay line anodes are finely arranged on the surface layer, while the underlying metal shielding ground layer has precise openings only at the node positions corresponding to the delay line anodes. This physically isolates and significantly reduces parasitic capacitive coupling between nodes, solving the problem of signal crosstalk between adjacent nodes caused by excessive lateral coverage of the electron cloud.

[0034] In some embodiments, to adapt to the requirements of omnipolar analysis with rapid switching between positive and negative ions, the control unit has a built-in omnipolar zeroing control operation module. When the detector switches between positive and negative polarities, during the interval between switching from the first polarity detection mode to the second polarity detection mode, the control unit simultaneously injects a specific set of alternating depolarization pulses into the first grid 6 and the second grid 7. In one specific embodiment, the potential amplitude range of the depolarization pulse is configured to be 300V to 600V, preferably 500V, and its alternating frequency range is configured to be 5kHz to 20kHz, preferably 10kHz. This high-frequency alternating pulse generates an alternating electric field in the vacuum region, which can rapidly induce and force the residual space charge adsorbed on the insulating layer on the surface of the delay line anode plate 8 to detach, and rapidly discharge it through the first grid 6 and the second grid 7 as active charge suction channels, thereby clearing the charge memory of the drift region within milliseconds, achieving transient baseline stability, and ensuring that the first frame of data after switching has an extremely high signal-to-noise ratio.

[0035] Corresponding to the time-delay linear position-sensitive detector provided in the foregoing embodiments, other embodiments of the present invention also provide a detection method for the time-delay linear position-sensitive detector. This method utilizes the aforementioned hardware structure and can effectively eliminate position and time deviations caused by different particle incident angles. For example... Figure 3 As shown, in the specific detection process, the microchannel plate assembly first receives incident particles, ions, or photons, which undergo multi-stage secondary electron multiplication within its stacked microchannels, and then outputs a charge cloud with high charge gain to the rear end. Next, the control unit applies a specific positive bias voltage to the first grid adjacent to the output end of the microchannel plate assembly, thereby establishing a strong longitudinal extraction and acceleration electric field between the output end of the microchannel plate assembly and the first grid. Because this extraction electric field has an extremely high potential gradient, it imparts an extremely high longitudinal velocity to the newly emitted electrons, forcing the electron cloud to accelerate rapidly forward before large-scale lateral diffusion and Coulomb repulsion expansion, and to be beam collimated longitudinally along the z-axis, thus suppressing the influence of geometric path difference on the total flight time to an extremely low level. During the forward flight of the electron cloud, the control unit applies a bias voltage to the second grid near the anode side, flattening the spatial electric field above the delay line anode plate to eliminate edge electric field distortion, allowing the collimated electron cloud to pass through the uniform electric field drift region between the first and second grids at a constant speed. During this period, utilizing the unique three-dimensional geometry of the metal mesh of the first and second grids, and through the specific ratio of mesh width to winding diameter, the edge-tilted electron flow, after being accelerated by the longitudinal accelerating electric field, still exceeding the set value in terms of emission angle, is physically intercepted and spatially captured. This significantly reduces the mesh throughput, thereby eliminating the large-angle emitted electron cloud component at the hardware level. Finally, the highly efficient electron cloud, after being collimated by the electric field, spatially confined, and physically intercepted, impacts the surface sensing layer of the delay line anode plate at a near-vertical angle. Through displacement current, a picosecond-level differential signal is excited within the delay line anode below. By accurately recording the time difference between the arrival of the pulse at both ends of the delay line, the system achieves high-precision synchronous reconstruction of two-dimensional time and space coordinates.

[0036] In some embodiments, to achieve a micrometer-level leap in spatial resolution and completely eliminate signal crosstalk between adjacent high-density sensing nodes, the detection method introduces an active electrostatic focusing control step during the transmission of the electron cloud. Specifically, the method induces an electrostatic lensing effect within the uniform drift region between the first and second grids by dynamically adjusting the potential difference between the first and second grids to a specific set threshold using a control unit. This electrostatic thin-lens focusing effect applies a lateral contraction force to the electron beam flying towards the delay line anode plate, forcing it to undergo secondary contraction and focusing before reaching the anode surface, compressing its lateral expansion radius by more than 60%, and ultimately strictly limiting the projection radius of the electron cloud on the anode plate to an extremely small sensing range of less than 50 micrometers. This focusing control step not only greatly improves the weight accuracy and resolution limit of the subsequent centroid reconstruction algorithm but also ensures that signal aliasing between adjacent sensing nodes does not occur at ultra-high count rates.

[0037] In some embodiments, to adapt to the requirements of all-polarity analysis with rapid alternation of positive and negative ions in the rapid analysis of complex components, the detection method further includes a dynamic charge discharge and baseline recovery step when the detector undergoes polarity switching. When the time-delay line potential-sensitive detector switches between positive and negative polarities, within the millisecond-level time interval between the transition from the first polarity detection mode to the second polarity detection mode, the control unit simultaneously applies a set of alternating depolarization pulses of a specific waveform to the first grid and the second grid. In one specific embodiment, the potential amplitude range of the alternating depolarization pulse is configured to be 300V to 600V, preferably 500V, and its alternating frequency range is configured to be 5kHz to 20kHz, preferably 10kHz. Under the action of this high-frequency alternating depolarization pulse, an alternating electric field is generated in the vacuum region. This electric field can rapidly destroy the electrostatic adsorption of surface charges, inducing and forcing the deposited space charges originally remaining on the insulating layer on the surface of the time-delay line anode plate, as well as the excess residual charges in the space, to detach from the surface constraint. Subsequently, the detached residual charge is rapidly drawn out and discharged through the first and second grids, which serve as active charge suction channels, thereby completely eliminating the charge memory effect inside the detector in a very short time. This achieves transient baseline stability in all-polarity analysis mode and ensures that the first frame of data after polarity switching has an extremely high signal-to-noise ratio.

[0038] In this specification, the illustrative expressions of the terms used do not necessarily refer 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.

[0039] Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention shall be included within the scope of protection of this invention.

Claims

1. A time-delay linear position-sensitive detector, characterized in that, include: Microchannel plate assembly for receiving incident particles and outputting a multiplied electron cloud; A delay line anode plate, disposed at the rear end of the microchannel plate assembly, is used to sense the electron cloud and generate position and time signals; A first grid and a second grid are sequentially disposed in the vacuum space between the microchannel plate assembly and the delay line anode plate, wherein the first grid is disposed near the output end of the microchannel plate assembly and the second grid is disposed near the delay line anode plate; A control unit, connected to the first grid and the second grid respectively, is used to apply an independently adjustable potential bias to the first grid and the second grid; The first grid is configured to apply a positive bias voltage higher than the output potential of the microchannel plate assembly to establish a longitudinal accelerating electric field between the microchannel plate assembly and the first grid, thereby forcibly compressing the electron emission angle. The second grid is configured to apply a bias voltage with a potential difference from the delay line anode plate within a set range to establish a uniform drift electric field between the first grid and the second grid, thereby eliminating electric field edge distortion and spatially focusing the electron cloud; and the first grid and the second grid use the physical shielding portion of their own metal mesh to physically block the electron flow emitted at a large angle.

2. The time-delay linear position-sensitive detector according to claim 1, characterized in that, The control unit has an all-polarity zeroing mode and is configured to apply alternating depolarization pulses to the first grid and the second grid during the interval when the delay line position sensor switches between positive and negative polarities, so as to use the first grid and the second grid as active suction electrodes to induce and discharge residual charges on the surface and in the space of the delay line anode plate.

3. The time-delay linear position-sensitive detector according to claim 1, characterized in that, The delay line anode plate includes a surface layer and a metal shielding ground layer disposed below the surface layer. The surface layer is provided with delay line anodes, and the metal shielding ground layer has openings only at the node positions corresponding to the delay line anodes to isolate parasitic capacitive coupling between nodes.

4. The time-delay linear position-sensitive detector according to claim 1, characterized in that, The microchannel plate assembly includes a first microchannel plate and a second microchannel plate stacked along the direction of electron movement. A grid electrode is provided in front of the input end of the first microchannel plate. The microchannel plate assembly, the first grid, the second grid, and the delay line anode plate are all isolated and supported by insulating pads, and are mechanically positioned by ceramic support rings on the periphery.

5. The time-delay linear position-sensitive detector according to claim 1, characterized in that, Both the first and second grids are metal honeycomb meshes with a transmittance greater than 81% and a mesh count of 100 to 300. And / or, the positive bias voltage of the first grid is 100V to 800V higher than the output potential of the microchannel plate assembly.

6. The time-delay linear position-sensitive detector according to claim 1, characterized in that, The distance between the first grid and the output end of the microchannel plate assembly is 0.3 mm to 1.5 mm; And / or, the spacing between the first grid and the second grid is 0.5 mm to 3.0 mm; And / or, the distance between the second grid and the delay line anode plate is 0.2 mm to 1.5 mm.

7. A detection method for a time-delay linear position-sensitive detector, characterized in that, Detection is performed based on a time-delay linear position-sensitive detector as described in any one of claims 1 to 6, characterized in that the method comprises: The microchannel plate assembly multiplies the output electron cloud; The control unit applies a positive bias voltage to the first grid to establish a longitudinal accelerating electric field, forcing the electron cloud to accelerate and collimate longitudinally before lateral diffusion; The control unit applies a bias voltage to the second grid to flatten the spatial electric field above the delay line anode plate, so that the collimated electron cloud passes through the second grid at a constant speed. By utilizing the physical grid structure of the first and second grids, an electron stream that still has a large exit angle after passing through the longitudinal accelerating electric field is intercepted; The electron cloud vertically impacts the delay line anode plate to generate a differential signal.

8. The detection method of the time-delay linear position-sensitive detector according to claim 7, characterized in that, When the time-delay line position-sensitive detector switches between positive and negative polarities, during the gap before switching from the first polarity detection to the second polarity detection, the control unit simultaneously applies alternating depolarization pulses to the first grid and the second grid, so as to release the residual charge on the surface and in the space of the time-delay line anode plate through the first grid and the second grid as active charge suction electrodes.

9. The detection method of the time-delay linear position-sensitive detector according to claim 7, characterized in that, By adjusting the potential difference between the first grid and the second grid to a set threshold, an electrostatic lens effect is generated between the first grid and the second grid, thereby performing secondary contraction and focusing on the electron beam flying toward the delay line anode plate.

10. The detection method of the time-delay linear position-sensitive detector according to claim 8, characterized in that, The alternating depolarization pulse has a potential amplitude range of 300V to 600V and a frequency range of 5kHz to 20kHz.

Images