Apparatus and method for measuring particle composition and direction of incidence

Abstract

The application belongs to the technical field of space plasma environment detection, and particularly relates to a device and method for measuring particle composition and incident direction, which comprises: a detection unit array, which is respectively provided with a plurality of independent charge input channels in an inner circumferential direction and an outer circumferential direction; each charge output channel is used for outputting different initial charge pulse signals in the inner circumferential direction and different terminal charge pulse signals in the outer circumferential direction after a space charged particle is incident at an incident angle, and delay and amplification are performed respectively; and a back-end circuit analysis processing module, which is used for obtaining actual time of flight and actual incident azimuth angle time of the charged particle according to different initial pulse signals and terminal pulse signals collected for each charge output channel, obtaining the composition of the charged particle according to the obtained actual time of flight of the charged particle, and obtaining the actual incident azimuth angle of the charged particle according to the actual incident azimuth angle time.

Description

[0001] This application is a divisional application of application number "202110924729.8", entitled "A synchronous measurement device and method for particle composition and azimuth angle based on time delay", filed on August 12, 2021. Technical Field

[0002] This invention belongs to the field of space plasma environment detection technology, specifically, it relates to a device and method for measuring particle composition and incident direction. Background Technology

[0003] Particle composition detection and incident orientation angle detection are important components of space particle detection. Over the past three decades, with the development of microchannel plate (MCP) technology and the increasing demand for particle detection research in military and space fields, a series of anode detectors with particle counting and orientation recognition functions have emerged. Currently, methods for particle incident orientation detection mainly include resistive anode detection, vernier anode detection, time-delay anode detection, cross-strip anode detection, and wedge-shaped anode detection.

[0004] However, existing detection methods suffer from problems such as complex manufacturing processes, slow speed, low count rate, large size, heavy weight, high power consumption, lack of temporal and spatial resolution, and low sensitivity. Furthermore, existing methods also face the technical challenge of simultaneously measuring particle composition and azimuth angle within a single device during space environment detection. Summary of the Invention

[0005] To address the aforementioned deficiencies in existing technologies, this invention proposes a synchronous measurement method for particle composition and azimuth angle based on time delay. This method uses only four charge-sensitive amplifiers to distinguish and acquire the position detection of 32 anodes within a 360° direction. The time measurement circuit acquires the anode delay time, and the accuracy of the measured system time (including anode, electronic layout and wiring, and signal transmission) is better than 1 nanosecond. By grouping the delay time, the azimuth angle resolution reaches 22.5°; the measured particle mass number ranges from 1 to 70 atoms.

[0006] The present invention provides a synchronous measurement device for particle composition and azimuth angle based on time delay. The device includes: a detection unit array and a back-end circuit analysis and processing module.

[0007] The detection unit array is provided with several independent charge input channels in both the inner and outer circumferential directions. Each charge output channel is used to detect charged particles in space at an incident angle. After incident, different initial charge pulse signals are output in the inner circumferential direction and different termination charge pulse signals are output in the outer circumferential direction. These signals are then delayed and amplified to obtain the corresponding initial and termination pulse signals.

[0008] The back-end circuit analysis and processing module is used to collect different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting pulse signals and ending pulse signals, the actual flight time and actual incident azimuth time of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0009] As an improvement to the above technical solution, the detection unit array includes: a particle incident device, an inner circular anode array, and an outer circular anode array; the inner and outer circular anode arrays are concentric annular structures, and the particle incident device covers the annular structure.

[0010] The inner circular anode subarray comprises multiple inner circular anodes arranged in a circular pattern, with delay lines connected in series between them. Each inner circular anode serves as a detection unit, independently outputting the incident angle emitted from the particle incident device. The initial charge pulse signal of a charged particle in space; the two adjacent inner circular anodes are respectively marked as the head end and tail end of the inner circular anode subarray, and a first preamplifier and a second preamplifier are respectively set on them to delay and amplify the collected initial charge pulse signal to obtain the initial pulse signal A and the initial pulse signal B; wherein, each inner circular anode has its own specific incident angle, and multiple inner circular anodes distributed in a circle form a 360-degree incident range;

[0011] The outer circular anode subarray comprises multiple circumferentially distributed outer circular anodes, with delay lines connected in series between them. Each outer circular anode serves as a detection unit, independently outputting the incident angle emitted from the particle incident device. The termination charge pulse signal of a charged particle in space; the two adjacent outer circular anodes are respectively designated as the beginning and end of the outer circular anode subarray, and a third preamplifier and a fourth preamplifier are respectively set on them to delay and amplify the acquired termination charge pulse signal, respectively, to obtain the termination start pulse signal A and the termination pulse signal B. Each outer circular anode 2 has its own specific incident angle, and multiple circumferentially distributed outer circular anodes form a 360-degree incident range.

[0012] As an improvement to the above technical solution, the particle injection device includes: an initiating carbon film plate, a terminating carbon film plate, a particle blocking film plate, and a microchannel plate.

[0013] The starting carbon film plate is located above the ending carbon film plate, and the two have corresponding inlet and outlet ports respectively. The two are sealed together and have deflection electrodes inside. The particle blocking film plate is located at the outlet of the ending carbon film plate and is located above the microchannel plate.

[0014] An accelerating voltage is added at the injection port of the initial carbon film plate. =-15000V, charged particles in space enter through the entrance port of the initial carbon film, pass through the initial carbon film, and lose energy. Simultaneously, secondary electrons are generated; these secondary electrons are deflected by the built-in deflection electrodes, pass through the exit port of the termination carbon film plate, and are incident on the microchannel plate, generating an initial charge pulse signal; at the same time, after passing through the space charged particles of the initial carbon film plate, they directly hit the termination carbon film plate and generate secondary electrons again. These secondary electrons continue to fly through the particle blocking film plate and are incident on the microchannel plate, generating a termination charge pulse signal.

[0015] As an improvement to the above technical solution, both the inner and outer circular anodes are time-delay line anode sheets, and both are made of printed circuit boards.

[0016] As one of the improvements to the above technical solution, the first preamplifier, the second preamplifier, the third preamplifier and the fourth preamplifier are all charge-sensitive amplifiers.

[0017] As an improvement to the above technical solution, a copper cladding is added to the middle of the annular structure, and the copper cladding is connected to the signal ground.

[0018] As one of the improvements to the above technical solution, the back-end circuit analysis and processing module includes: a signal acquisition unit and a data processing unit;

[0019] The signal acquisition unit is used to acquire different start pulse signals in the inner circumferential direction and different termination pulse signals in the outer circumferential direction for each charge output channel.

[0020] The data processing unit is used to obtain the actual flight time and actual incident azimuth time of the charged particle based on the different start pulse signals and end pulse signals collected. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0021] As one improvement to the above technical solution, the specific process of the data processing unit is as follows:

[0022] The signal acquisition unit is used to acquire the start pulse signal A, the end pulse signal A, the start pulse signal B, and the end pulse signal B;

[0023] The time difference between the initial pulse signal A and the termination pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the initial pulse signal B and the termination pulse signal B is equal to the second flight time τ2 of the particle.

[0024] A correlation analysis was performed on the first and second flight times of the particles; the conditions were met: 0 < τ1, τ2 < maximum flight time of the ions. ,and .

[0025] Determine the actual flight time of the particles :

[0026] ;

[0027] Determine the mass-to-charge ratio of the particle based on its actual flight time. :

[0028]

[0029] in, The mass of the particle; The charge of the particle; The incident energy of the particle; electron charge ; To accelerate voltage; The energy lost by the particles; This represents the distance the particle travels.

[0030] Measure the time difference between the initial pulse signal A and the initial pulse signal B. The time difference between termination pulse signal A and termination pulse signal B ;

[0031] Will and Correlation analysis was performed to ensure that the minimum incident azimuth time of the particle is less than τ3 and τ4 is less than the maximum incident azimuth time of the particle. ,and ;

[0032] Determine the actual incident azimuth time of the particle :

[0033]

[0034] Based on the actual incident azimuth time of the particle, and using the azimuth time lookup table, the actual incident azimuth of the particle is determined.

[0035] This invention also provides a method for synchronous measurement of particle composition and azimuth angle based on time delay, the method comprising:

[0036] Charged particles in space, at the angle of incidence The incident pulse signals are output with different initial charge pulse signals in the inner circumferential direction and different termination charge pulse signals in the outer circumferential direction. These signals are then delayed and amplified to obtain the corresponding initial and termination pulse signals.

[0037] The back-end circuit analysis and processing module collects different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting and ending pulse signals, the actual flight time and actual incident azimuth time of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0038] As an improvement to the above technical solution, the back-end circuit analysis and processing module collects different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting and ending pulse signals, the actual flight time and actual incident azimuth angle of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth angle, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle. The specific process is as follows:

[0039] The signal acquisition unit acquires different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel.

[0040] The data processing unit obtains the actual flight time and actual incident azimuth angle of the charged particle based on the different start pulse signals and end pulse signals collected. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0041] Specifically, the signal acquisition unit is used to acquire the start pulse signal A, the end pulse signal A, the start pulse signal B, and the end pulse signal B;

[0042] The time difference between the initial pulse signal A and the termination pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the initial pulse signal B and the termination pulse signal B is equal to the second flight time τ2 of the particle.

[0043] A correlation analysis was performed on the first and second flight times of the particles; the conditions were met: 0 < τ1, τ2 < maximum flight time of the ions. ,and .

[0044] Determine the actual flight time of the particles :

[0045] ;

[0046] Determine the mass-to-charge ratio of the particle based on its actual flight time. :

[0047]

[0048] in, The mass of the particle; The charge of the particle; The incident energy of the particle; Sub-charge ; To accelerate voltage; The energy lost by the particles; This represents the distance the particle travels.

[0049] Measure the time difference between the initial pulse signal A and the initial pulse signal B. The time difference between termination pulse signal A and termination pulse signal B ;

[0050] Will and Correlation analysis was performed to ensure that the minimum incident azimuth time of the particle is less than τ3 and τ4 is less than the maximum incident azimuth time of the particle. ,and ;

[0051] Determine the actual incident azimuth time of the particle :

[0052]

[0053] Based on the actual incident azimuth time of the particle, and using the azimuth time lookup table, the actual incident azimuth of the particle is determined.

[0054] The beneficial effects of this invention compared to the prior art are:

[0055] The device of this invention can solve the technical problem of synchronous measurement of particle composition and azimuth angle in a single device in space environment detection, greatly reducing the weight of the instrument and power consumption. It has a wide range of applications in the field of space exploration, especially in the field of deep space exploration, where resources such as weight and power consumption are scarce. In addition, the high-time-accuracy inner and outer circular anodes used in this invention are both time-delay anode sheets, which can improve the accuracy of the delay time error caused by inconsistent anode area size and the layout and wiring of printed circuit boards to less than 1 nanosecond, greatly improving the resolution of particle composition and azimuth angle. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the structure of a synchronous measurement device for particle composition and azimuth angle based on time delay according to the present invention;

[0057] Figure 2 This is a schematic diagram of the detection unit array of a synchronous measurement device for particle composition and azimuth angle based on time delay according to the present invention;

[0058] Figure 3 This is a schematic diagram of the structure of the inner circular anode hollowed out (white) in the middle layer of the detection unit array of a synchronous measurement device for particle composition and azimuth angle based on time delay according to the present invention;

[0059] Figure 4 This is a schematic diagram of the inner circular anode subarray of the detection unit array of a synchronous measurement device for particle composition and azimuth angle based on time delay according to the present invention.

[0060] Figure 5 This is a schematic diagram of the outer circular anode subarray of the detection unit array of a synchronous measurement device for particle composition and azimuth angle based on time delay according to the present invention;

[0061] Figure 6 This is a flowchart of a specific embodiment of a synchronous measurement method for particle composition and azimuth angle based on time delay according to the present invention;

[0062] Figure 7 This is a functional block diagram of a time-delay-based synchronous measurement device for particle composition and azimuth angle, which uses a time-measuring FPGA to measure azimuth angle time.

[0063] Figure 8 This is a diagram illustrating the working mechanism of a time interval measurement FPGA for a synchronous measurement device based on time delay of particle composition and azimuth angle according to the present invention.

[0064] Attachment title:

[0065] 1. Inner anode 2. Outer anode

[0066] 3. Initial carbon film 4. Termination carbon film

[0067] 5. Ion blocking membranes 6. Microchannel plates

[0068] 7. Secondary electrons 8. Secondary electrons

[0069] 9. Deflection electrode Detailed Implementation

[0070] The present invention will now be further described in conjunction with the accompanying drawings and examples.

[0071] The present invention provides a synchronous measurement device for particle composition and azimuth angle based on time delay. The device includes: a detection unit array and a back-end circuit analysis and processing module.

[0072] The detector array has several independent charge output channels in both the inner and outer circumferential directions. Each charge output channel is used to detect charged particles in space at an incident angle. After incident, different initial charge pulse signals are output in the inner circumferential direction and different termination charge pulse signals are output in the outer circumferential direction, and these are amplified to obtain the corresponding initial pulse signal and termination pulse signal.

[0073] The back-end circuit analysis and processing module is used to collect different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting pulse signals and ending pulse signals, the actual flight time and actual incident azimuth time of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0074] Among them, such as Figure 1 , 2 As shown in Figure 3, the detection unit array includes: a particle injection device, an inner circular anode array, and an outer circular anode array; the inner and outer circular anode arrays are concentric annular structures, and the particle injection device covers the annular structure.

[0075] Among them, such as Figure 4 As shown, the inner circular anode subarray includes multiple inner circular anodes 1 arranged in a circular pattern, and delay lines are connected in series between the inner circular anodes 1. Each inner circular anode 1 serves as a detection unit, independently outputting the incident angle emitted from the particle incident device. The initial charge pulse signal of a charged particle in space; the two adjacent inner circular anodes 1 are respectively marked as the head end and tail end of the inner circular anode subarray, and a first preamplifier and a second preamplifier are respectively set on them to delay and amplify the collected initial charge pulse signal to obtain the initial pulse signal A and the initial pulse signal B; wherein, each inner circular anode 1 has its own specific incident angle, and multiple inner circular anodes 1 distributed in a circle form a 360-degree incident range;

[0076] like Figure 5 As shown, the outer circular anode subarray includes: multiple outer circular anodes 2 distributed in a circular pattern, with delay lines connected in series between the outer circular anodes 2. Each outer circular anode 2 serves as a detection unit, independently outputting the incident angle emitted from the particle incident device. The termination charge pulse signal of the charged particles in space; the two adjacent outer circular anodes 2 are respectively designated as the beginning and end of the outer circular anode subarray, and a third preamplifier and a fourth preamplifier are respectively set on them to delay and amplify the collected termination charge pulse signal, respectively, to obtain the termination start pulse signal A and the termination pulse signal B. Among them, each outer circular anode 2 has its own specific incident angle, and multiple outer circular anodes 2 distributed in a circle form a 360-degree incident range.

[0077] The particle incident device includes: an initiating carbon film plate 3, a terminating carbon film plate 4, a particle blocking film plate 5, and a microchannel plate 6.

[0078] Both the starting carbon film plate 3 and the ending carbon film plate 4 include the use of 1.5~2.0 μg / cm 2 The ultra-thin carbon film and honeycomb stainless steel mesh structure are manufactured using the following methods:

[0079] The ultrathin carbon film is placed in deionized water and floats on the surface of the deionized water. Then, a honeycomb stainless steel mesh structure is used to retrieve the ultrathin carbon film and fix it on the stainless steel mesh structure to form the starting carbon film plate 3 and the ending carbon film plate 4.

[0080] The starting carbon film plate 3 is located above the ending carbon film plate 4, and the two have corresponding inlet and outlet ports respectively. They are sealed together and have a deflection electrode 9 inside. The particle blocking film plate 5 is located at the outlet of the ending carbon film plate 4 and is located above the microchannel plate 6.

[0081] An accelerating voltage is added at the injection port of the initial carbon film plate 3. =15000V, charged particles in space enter through the entrance port of the initial carbon film plate 3, pass through the initial carbon film plate 3 and lose energy. Simultaneously, secondary electrons 7 are generated; these secondary electrons 7 are deflected by the built-in deflection electrode 9, pass through the exit port of the termination carbon film plate 4, and are incident on the microchannel plate 6, generating an initial charge pulse signal; at the same time, after passing through the space charged particles of the initial carbon film plate 3 and flying a distance d, they directly hit the termination carbon film plate 4 and generate secondary electrons 8 again. These secondary electrons 8 continue to fly through the particle blocking film plate 5 and are incident on the microchannel plate 6, generating a termination charge pulse signal.

[0082] The deflection electrode 9 is a high-voltage component, surrounded by multiple low-voltage components. Both the high-voltage and low-voltage components are spatially isolated and separated by polyimide material to ensure safety. The high-voltage component is loaded with 15000V, causing the secondary electrons 7 generated by the initial carbon film 3 to be deflected and strike the MCP, whereupon the signal is collected by the initial anode.

[0083] Both the inner circular anode 1 and the outer circular anode 2 are time-delay line anode sheets, both made of printed circuit boards, and the time accuracy error of the inner circular anode and the outer circular anode is controlled to be less than 1 nanosecond.

[0084] The first, second, third, and fourth preamplifiers are all charge-sensitive amplifiers.

[0085] The structural diagram of the inner circular anode subarray is as follows: Figure 4 As shown, Figure 4 The inner anodes are inner circular anodes, and this inner circular anode subarray includes 16 inner anodes connected end-to-end. A delay line is connected in series before each inner anode to measure the charge of the initial charge pulse signal generated when it strikes the microchannel plate. Inner anode 1 serves as the starting end, connected to preamplifier A as the first preamplifier, and inner anode 16 serves as the ending end, connected to preamplifier B as the second preamplifier. Preamplifier A and preamplifier B respectively delay, amplify, and perform analog-to-digital conversion on the incident initial charge pulse signal to obtain the corresponding initial digital pulse signal, i.e., starting signal A and starting signal B.

[0086] The structural diagram of the outer circular anode subarray is shown in Figure 5. Figure 5 The outer anodes in the array are circular anodes, and this array of circular anodes includes 16 outer anodes connected end-to-end. A delay line is connected in series before each outer anode to measure the charge of the termination charge pulse signal generated when it strikes the microchannel plate. Outer anode 1 serves as the starting point, connected to preamplifier A as the third preamplifier, and outer anode 16 serves as the ending point, connected to preamplifier B as the fourth preamplifier. Preamplifiers A and B respectively delay, amplify, and perform analog-to-digital conversion on the incident termination charge pulse signal to obtain the corresponding termination digital pulse signals, namely termination signal A and termination signal B.

[0087] To amplify minute charge signals, a high-sensitivity preamplifier is required; to measure time of flight, the preamplifier used in this invention has a very high response speed.

[0088] The annular structure has an additional copper layer in the middle, which is connected to the signal ground for signal shielding.

[0089] The back-end circuit analysis and processing module includes: a signal acquisition unit and a data processing unit;

[0090] The signal acquisition unit is used to acquire different start pulse signals in the inner circumferential direction and different termination pulse signals in the outer circumferential direction for each charge output channel.

[0091] The data processing unit is used to obtain the actual flight time and actual incident azimuth time of the charged particle based on the different start pulse signals and end pulse signals collected. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0092] Specifically, the data processing unit performs the following process:

[0093] The signal acquisition unit is used to acquire the start pulse signal A, the end pulse signal A, the start pulse signal B, and the end pulse signal B;

[0094] The time difference between the initial pulse signal A and the termination pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the initial pulse signal B and the termination pulse signal B is equal to the second flight time τ2 of the particle.

[0095] A correlation analysis was performed on the first and second flight times of the particles; the conditions were met: 0 < τ1, τ2 < maximum flight time of the ions. ,and

[0096] Determine the actual flight time of the particles :

[0097] ;

[0098] Determine the mass-to-charge ratio of the particle based on its actual flight time. :

[0099]

[0100] in, The mass of the particle; The charge of the particle; The incident energy of the particle; Sub-charge ; To accelerate voltage; The energy lost by the particles; This represents the distance the particle travels.

[0101] Measure the time difference between the initial pulse signal A and the initial pulse signal B. The time difference between termination pulse signal A and termination pulse signal B ;

[0102] Will and Correlation analysis was performed to ensure that the minimum incident azimuth time of the particle is less than τ3 and τ4 is less than the maximum incident azimuth time of the particle. ,and ;

[0103] Determine the actual incident azimuth time of the particle :

[0104]

[0105] Based on the determined actual incident azimuth time of the particle, and using an azimuth-time lookup table, the actual incident azimuth of the particle is determined. This azimuth-time lookup table is a measured azimuth-time lookup table created based on specific instruments and equipment; it is a known table.

[0106] like Figure 6 As shown, Figure 6 The diagram shows the time measurement circuit system block diagram. In this embodiment, the start signal A and the stop signal A are measured by a TDC-GP1 chip to obtain the flight time τ1; the start signal B and the stop signal B are measured by another TDC-GP1 chip to obtain the flight time τ2; the actual flight time of the particle is determined based on the flight time τ1 and the flight time τ2; the start signal A and the start signal B are measured by the time measurement FPGA to obtain the incident azimuth time τ3; the stop signal A and the stop signal B are measured by the time measurement FPGA to obtain the incident azimuth time τ4; the actual incident azimuth time of the particle is determined based on the incident azimuth time τ3 and the incident azimuth time τ4.

[0107] like Figure 7As shown, since the order of the starting signals A and B is uncertain, and the order of the ending signals A and B is also uncertain, the TDC-GP series chips cannot be used to complete the measurement. Azimuth time measurement is implemented using a time measurement FPGA. To ensure the accuracy of the time measurement, the FPGA also has an internal temperature compensation algorithm to correct the measurement results for temperature variations. Its function and data flow diagram are shown below. Figure 7 As shown, Figure 7 A software functional block diagram of a time measurement FPGA is presented, where the time measurement function is implemented by internal logic resources. The solution for achieving high-precision time measurement in an FPGA combines coarse counting with fine time measurement. Coarse counting is implemented using a counter driven by an internal clock signal at a clock frequency of 40MHz. Fine time measurement employs time interpolation, using delay units (or gate circuits) to precisely phase-shift the input pulse signal. The relative position of the measured signal on the delay chain is used to determine the minute offset of the input signal relative to the coarse counting clock edge. The FPGA time measurement chip of this invention can achieve a minimum measurement time of 3 nanoseconds and a resolution of 300 ps.

[0108] Figure 7 Reset in

[0109] For externally input asynchronous signals such as power-on reset signals, asynchronous reset and synchronous release processing is required. This makes the designed circuit more reliable in terms of synchronization, which is beneficial for subsequent timing analysis and timing convergence. In addition, the maximum clock frequency Fmax of the synthesized circuit will be higher, which is beneficial to improving the overall circuit performance.

[0110] Figure 7 Instruction parsing and control

[0111] The main control FPGA performs read and write access operations on the time measurement FPGA by generating corresponding control signals, address signals, and data bus signals. The time measurement FPGA needs to judge and parse the bus access of the main control FPGA. If the access operation is valid, it needs to parse the configured parameters, generate corresponding control signals internally, or send data to other functional modules.

[0112] Figure 7 Time measurement in

[0113] Time measurement is one of the core functions of a time measurement FPGA, and this function is implemented using the logic gate units inside the FPGA chip. In this project, the two digital pulse output channels of the preamplifier correspond to channels τ3 and τ4, respectively. The input signals of channel τ3 are START_A and START_B, and the input signals of channel τ4 are STOP_A and STOP_B.

[0114] The START_A signal for channel τ3 is input_a_st, and the START_B signal is input_a_sp. The STOP_A signal for channel τ4 is input_b_st, and the STOP_B signal is input_b_sp. The time measurement functions of the two channels are independent and can be performed simultaneously.

[0115] The time measurement function of an FPGA is implemented using the FPGA's internal logic resources. A solution for achieving high-precision time measurement in an FPGA is a combination of coarse counting and fine time measurement. Coarse counting is implemented using a counter driven by an internal clock signal within the FPGA, with a timing clock frequency of 42MHz. In other specific embodiments, other clock frequencies can be selected depending on the required time measurement accuracy. Fine time measurement employs time interpolation, using delay units (OR gates) to precisely phase-shift the input pulse signal. The slight offset of the input signal relative to the coarse counting clock edge is determined by measuring the relative position of the signal on the delay chain.

[0116] The time measurement FPGA has two time measurement channels. Each time measurement channel actually includes two time interpolation time measurement units, namely, one time interpolation time measurement unit for each of the Start and Stop signals.

[0117] Based on the resource characteristics of the FPGA chip, an OR gate logic circuit is used to implement the delay unit for time measurement. (Next) Figure 8 This is a schematic diagram of the logic unit (Versatile) of the ProASIC Plus series FPGA. It can be configured as a logic gate (such as an OR gate circuit) to implement a delay chain unit.

[0118] Figure 7 INL correction

[0119] Because the delay values ​​of each unit in the time measurement delay chain deviate from the average code width (i.e., differential nonlinearity, or DNL), the accumulation of these DNL values ​​leads to integral nonlinearity (INL), thus causing measurement time errors. To achieve the required measurement accuracy, the fine time measurement values ​​need to be corrected. The correction method is to use a lookup table, which is the INL correction parameter table.

[0120] Therefore, during the soldering and debugging phase, after the time measurement logic is downloaded to the FPGA, two pulse signals need to be generated using a signal generator and sent to the Start and Stop interfaces of the time measurement respectively. The frequency of the signal source should be weakly correlated with the frequency of the FPGA input clock crystal. When the time measurement output data reaches a certain statistical quantity, the raw data is analyzed and processed to obtain the INL value corresponding to each fine count code. This generates a correction parameter table that corresponds one-to-one between the fine count code and the INL value. This table is added to the time measurement logic, and the new logic is downloaded to the FPGA to realize the time measurement correction function.

[0121] The entire INL parameter correction adopts a pipelined working mode. The 6-bit fine code (FineCode[5:0]) obtained from the time measurement delay chain module enters the correction parameter table, and an INL value can be obtained. This value is used as the final correction result DataOut[8:0] output.

[0122] The timing measurement FPGA has two timing measurement channels, therefore there are four timing measurement modules (Start_A, Start_B, Stop_A, Stop_B). Each timing measurement module needs to implement the above... Figure 7 The correction function is shown. Since the INL characteristic changes with temperature, it is necessary to conduct tests at different temperatures beforehand to generate multiple INL tables. During actual operation, the FPGA internally selects the corresponding INL parameter table for correction based on the temperature measurement results collected by the current temperature acquisition module.

[0123] Figure 7 Temperature measurement in

[0124] Two temperature sensor chips, DS18S20Z, are installed on the PCB near the time measurement FPGA. The time measurement FPGA needs to periodically collect temperature information as the basis for the INL correction module to select the parameter correction table.

[0125] Under normal operating conditions, the DS18S20Z has a minimum temperature measurement accuracy of 0.5℃. When the actual measured temperature is below +40℃, the INL correction step size is set to 8℃; when the actual measured temperature is +40℃ or above, the INL correction step size is set to 4℃. Therefore, based on the actual temperature measurement, the temperature range within the normal range (-40℃ to +45℃) is grouped and coded. When the correction step size is 8℃, the 16 temperature points collected by the DS18S20Z are grouped together; when the correction step size is 4℃, the 8 temperature points collected by the DS18S20Z are grouped together. This serves as the basis for the subsequent INL correction module to select the corresponding INL correction parameter table.

[0126] Figure 7 Data output

[0127] The data output function is mainly divided into two parts. One function is to return the corresponding internal read register value to the main control FPGA based on the read address information of the current main control FPGA operation. The other function is to store the time interval measurement value in the internal FIFO and notify the main control FPGA to read it by generating an interrupt signal.

[0128] The following details the output processing of the time interval measurement value. First, after the time measurement FPGA receives the Start (or Stop) signal in each time measurement channel, it waits for the next Start (or Stop) signal that is paired with it, and writes the measurement value of the time interval between the rising edges of the two signals (TSTART_B-TSTART_A or TSTART_A-TSTART_B) into the first-in-first-out buffer (FIFO) for the main control FPGA to read.

[0129] like Figure 8 As shown in the diagram, the upward arrow represents the Start_A signal, the downward arrow represents the Start_B signal, and the dashed line represents an invalid pulse signal that is discarded during the measurement process. The Start_A signal can occur after or before the Start_B signal. The time interval measurement data is a signed integer (negative numbers are in two's complement format). If the Start_B signal follows, the time interval measurement value is positive; otherwise, it is negative. The time interval measurement principle of the Stop signal is the same as that of the Start signal.

[0130] The measuring device of this invention can measure a time range of -150ns to +150ns. That is, after each first Start or Stop signal arrives, the time measurement FPGA searches only for the first matching signal within the time range of 0ns to 150ns, discarding any Start or Stop signals outside this range. After receiving each Start (or Stop) signal, any second or subsequent Start (or Stop) signals are also discarded during the current measurement process. The sign of the time measurement range indicates that a positive sign means the Start signal arrives first, and a negative sign means the Stop signal arrives first.

[0131] After each time measurement channel receives a Start (or Stop) signal, it waits for the immediately following paired Start (or Stop) signal and writes the measurement value of the time interval between the rising edges of these two signals to the FIFO buffer, waiting for the main control FPGA to read it. At the same time, an interrupt signal (active high) needs to be issued to notify the main control FPGA to read it. After the main control FPGA responds to the interrupt signal and reads the FIFO, it automatically clears the interrupt signal and prepares for the next time measurement.

[0132] This invention also provides a method for synchronous measurement of particle composition and azimuth angle based on time delay, the method comprising:

[0133] Charged particles in space, at the angle of incidence The incident pulse signals are output with different initial charge pulse signals in the inner circumferential direction and different termination charge pulse signals in the outer circumferential direction. These signals are then delayed and amplified to obtain the corresponding initial and termination pulse signals.

[0134] The back-end circuit analysis and processing module collects different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting and ending pulse signals, the actual flight time and actual incident azimuth time of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0135] Specifically, the signal acquisition unit acquires different starting pulse signals in the inner circumferential direction and different termination pulse signals in the outer circumferential direction for each charge output channel;

[0136] The data processing unit obtains the actual flight time and actual incident azimuth angle of the charged particle based on the different start pulse signals and end pulse signals collected. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0137] Specifically, the signal acquisition unit is used to acquire the start pulse signal A, the end pulse signal A, the start pulse signal B, and the end pulse signal B;

[0138] The time difference between the initial pulse signal A and the termination pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the initial pulse signal B and the termination pulse signal B is equal to the second flight time τ2 of the particle.

[0139] A correlation analysis was performed on the first and second flight times of the particles; the conditions were met: 0 < τ1, τ2 < maximum flight time of the ions. ,and .

[0140] Determine the actual flight time of the particles :

[0141] ;

[0142] Determine the mass-to-charge ratio of the particle based on its actual flight time. :

[0143]

[0144] in, The mass of the particle; The charge of the particle; The incident energy of the particle; Sub-charge ; To accelerate voltage; The energy lost by the particles; This represents the distance the particle travels.

[0145] Measure the time difference between the initial pulse signal A and the initial pulse signal B. The time difference between termination pulse signal A and termination pulse signal B ;

[0146] Will and Correlation analysis was performed to ensure that the minimum incident azimuth time of the particle is less than τ3 and τ4 is less than the maximum incident azimuth time of the particle. ,and ;

[0147] Determine the actual incident azimuth time of the particle :

[0148]

[0149] Based on the actual incident azimuth time of the particle, and using the azimuth time lookup table, the actual incident azimuth of the charged particle is determined.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A device for measuring particle composition and incident direction, characterized in that, The device includes: a detection unit array and a back-end circuit analysis and processing module; The detection unit array is provided with several independent charge input channels in both the inner and outer circumferential directions. Each charge output channel is used to detect charged particles in space at an incident angle. After incident, different initial charge pulse signals are output in the inner circumferential direction and different termination charge pulse signals are output in the outer circumferential direction. These signals are then delayed and amplified to obtain the corresponding initial and termination pulse signals. The back-end circuit analysis and processing module is used to collect different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting pulse signals and ending pulse signals, the actual flight time and actual incident azimuth time of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle. The back-end circuit analysis and processing module includes: a signal acquisition unit and a data processing unit; The signal acquisition unit is used to acquire different start pulse signals in the inner circumferential direction and different termination pulse signals in the outer circumferential direction for each charge output channel. The data processing unit is used to obtain the actual flight time and actual incident azimuth time of the charged particle based on the different start pulse signals and end pulse signals collected; to obtain the composition of the charged particle based on the actual flight time of the charged particle; and to obtain the actual incident azimuth of the charged particle based on the actual incident azimuth time, thereby realizing the synchronous measurement of the particle composition and incident azimuth of the charged particle. The specific process of the data processing unit is as follows: The signal acquisition unit is used to acquire the start pulse signal A, the end pulse signal A, the start pulse signal B, and the end pulse signal B; The time difference between the initial pulse signal A and the termination pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the initial pulse signal B and the termination pulse signal B is equal to the second flight time τ2 of the particle. Perform correlation analysis on the first and second flight times of the particles; satisfy... 0 < τ1 , τ2< Maximum flight time of ions; ,and ; Determine the actual flight time of the particles : ； Determine the mass-to-charge ratio of the particle based on its actual flight time. : ； in, The mass of the particle; The charge of the particle; The incident energy of the particle; electron charge ; To accelerate voltage; The energy lost by the particles; This represents the distance the particle travels. Measure the time difference between the initial pulse signal A and the initial pulse signal B. The time difference between termination pulse signal A and termination pulse signal B ; Will and Correlation analysis was performed to ensure that the minimum incident azimuth time of the particle is less than τ3 and τ4 is less than the maximum incident azimuth time of the particle. ,and ; Determine the actual incident azimuth time of the particle : ； Based on the actual incident azimuth time of the particle, and using the azimuth time lookup table, the actual incident azimuth of the charged particle is determined.

2. The device for measuring particle composition and incident direction according to claim 1, characterized in that, The detection unit array includes: a particle injection device, an inner circular anode array, and an outer circular anode array; the inner and outer circular anode arrays are concentric annular structures, and the particle injection device covers the annular structure. The inner circular anode subarray includes multiple inner circular anodes (1) arranged in a circular pattern, and delay lines are connected in series between the inner circular anodes (1). Each inner circular anode (1) serves as a detection unit and independently outputs the incident angle emitted from the particle incident device. The initial charge pulse signal of the charged particles in space; the two adjacent inner circular anodes (1) are respectively marked as the head end and tail end of the inner circular anode subarray, and a first preamplifier and a second preamplifier are respectively set on them to delay and amplify the collected initial charge pulse signal to obtain the initial pulse signal A and the initial pulse signal B; wherein, each inner circular anode (1) has its own specific incident angle, and multiple inner circular anodes (1) distributed in a circle form a 360-degree incident range; The outer circular anode subarray includes: multiple outer circular anodes (2) arranged in a circular pattern, and delay lines are connected in series between the outer circular anodes (2). Each outer circular anode (2) serves as a detection unit and independently outputs the incident angle emitted from the particle incident device. The termination charge pulse signal of the charged particles in space; the two adjacent outer anodes (2) are respectively marked as the beginning and end of the outer anode subarray, and a third preamplifier and a fourth preamplifier are respectively set on them to delay and amplify the collected termination charge pulse signal to obtain the termination start pulse signal A and termination pulse signal B; wherein, each outer anode (2) has its own specific incident angle, and multiple outer anodes (2) distributed in a circle form a 360-degree incident range; The particle incident device includes: an initiating carbon film plate (3), a terminating carbon film plate (4), a particle blocking film plate (5), and a microchannel plate (6). The starting carbon film plate (3) is located above the ending carbon film plate (4), and the two have corresponding inlet and outlet ports respectively. The two are sealed together and have deflection electrodes (9) inside. The particle blocking film plate (5) is located at the outlet of the ending carbon film plate (4) and is located above the microchannel plate (6). An accelerating voltage is added at the injection port of the initial carbon film plate (3). =-15000V, charged particles in space enter through the inlet of the initial carbon film plate (3), pass through the initial carbon film plate (3) and lose energy. At the same time, secondary electrons (7) are generated. These secondary electrons (7) are deflected by the built-in deflection electrode (9), pass through the exit port of the termination carbon film plate (4), and are incident on the microchannel plate (6), generating an initial charge pulse signal. At the same time, after passing through the space charged particle flight distance of the initial carbon film plate (3), they directly hit the termination carbon film plate (4) and generate secondary electrons (8) again. These secondary electrons (8) continue to fly through the particle blocking film plate (5) and are incident on the microchannel plate (6), generating a termination charge pulse signal.

3. The device for measuring particle composition and incident direction according to claim 2, characterized in that, Both the inner circular anode (1) and the outer circular anode (2) are delay line anode sheets, and both are made of printed circuit boards.

4. The device for measuring particle composition and incident direction according to claim 2, characterized in that, The first, second, third, and fourth preamplifiers are all charge-sensitive amplifiers.

5. The device for measuring particle composition and incident direction according to claim 2, characterized in that, A copper layer is added to the middle of the ring structure, and the copper layer is connected to the signal ground.

6. A method for measuring particle composition and incident direction, the method being implemented based on the device for measuring particle composition and incident direction as described in any one of claims 1-5, characterized in that, The method includes: Charged particles in space, at the angle of incidence The incident pulse signals are output with different initial charge pulse signals in the inner circumferential direction and different termination charge pulse signals in the outer circumferential direction. The pulse signals are then delayed and amplified to obtain the corresponding initial and termination pulse signals. The back-end circuit analysis and processing module collects different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting and ending pulse signals, the actual flight time and actual incident azimuth time of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth time, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

7. The method for measuring particle composition and incident direction according to claim 6, characterized in that, The back-end circuit analysis and processing module collects different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. Based on the collected different starting and ending pulse signals, the actual flight time and actual incident azimuth angle of the charged particle are obtained. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained. Based on the actual incident azimuth angle, the actual incident azimuth angle of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle. The specific process is as follows: The signal acquisition unit acquires different starting pulse signals in the inner circumferential direction and different ending pulse signals in the outer circumferential direction for each charge output channel. The data processing unit obtains the actual flight time and actual incident azimuth angle of the charged particle based on the different start pulse signals and end pulse signals collected. Based on the actual flight time of the charged particle, the composition of the charged particle is obtained, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle. Specifically, the signal acquisition unit is used to acquire the start pulse signal A, the end pulse signal A, the start pulse signal B, and the end pulse signal B; The time difference between the initial pulse signal A and the termination pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the initial pulse signal B and the termination pulse signal B is equal to the second flight time τ2 of the particle. A correlation analysis was performed on the first and second flight times of the particles; the conditions were met: 0 < τ1, τ2 < maximum flight time of the ions. ,and ; Determine the actual flight time of the particles : ； Determine the mass-to-charge ratio of the particle based on its actual flight time. : ； in, The mass of the particle; The charge of the particle; The incident energy of the particle; Sub-charge ; To accelerate voltage; The energy lost by the particles; This represents the distance the particle travels. Measure the time difference between the initial pulse signal A and the initial pulse signal B. The time difference between termination pulse signal A and termination pulse signal B ; Will and Correlation analysis was performed to ensure that the minimum incident azimuth time of the particle is less than τ3 and τ4 is less than the maximum incident azimuth time of the particle. ,and ; Determine the actual incident azimuth time of the particle : ； Based on the actual incident azimuth time of the particle, and using the azimuth time lookup table, the actual incident azimuth of the charged particle is determined.

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