A synchronous measurement device and method for particle composition and azimuth angle based on time delay

Abstract

The present invention belongs to the technical field of space plasma environment detection, and specifically relates to a synchronous measurement device for particle composition and azimuth angle based on time delay, comprising: a detection unit array having a plurality of independent charge input channels respectively provided in the inner circumferential direction and the outer circumferential direction, each charge output channel being used for outputting different starting charge pulse signals in the inner circumferential direction and different ending charge pulse signals in the outer circumferential direction after a space charged particle is incident at an incident angle θ, and performing delay and amplification respectively; and a back-end circuit analysis and processing module being used for obtaining, for each charge output channel, the actual flight time and actual incident azimuth angle time of the charged particle based on different collected starting pulse signals and ending pulse signals, obtaining the composition of the charged particle based on the obtained actual flight time of the charged particle, and obtaining the actual incident azimuth angle of the charged particle based on the actual incident azimuth angle time.

Description

Technical Field

[0001] The present invention belongs to the technical field of space plasma environment detection, and in particular relates to a device and method for synchronously measuring particle composition and azimuth angle based on time delay. Background Art

[0002] Particle composition detection and incident azimuth angle detection are crucial components of space particle detection. Over the past three decades, with the advancement of microchannel plate (MCP) technology and the increasing demand for particle detection in military and space applications, a series of anode detectors with particle counting and direction recognition capabilities have emerged. Currently, the main methods for detecting particle incident azimuth include resistance anode detection, vernier anode detection, time-delay anode detection, cross-stripe anode detection, and wedge-strip anode detection.

[0003] However, existing detection methods suffer from complex manufacturing processes, slow speed, low count rates, large size, heavy weight, high power consumption, lack of temporal and spatial resolution, and low sensitivity. Furthermore, existing methods also suffer from the technical problem of being unable to simultaneously measure particle composition and azimuth within a single device for space environment detection. Summary of the Invention

[0004] To address the above-mentioned defects in the prior art, the present 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 collect position detection of 32 anodes within a 360° direction. The time measurement circuit collects the anode delay time. The measured system time (including anode, electronic layout wiring, and signal transmission) has an accuracy better than 1 nanosecond. By grouping the delay time, the measurement azimuth angle resolution reaches 22.5°; the measured particle mass number range is 1-70 atomic weights.

[0005] The present invention provides a device for synchronously measuring particle composition and azimuth based on time delay, the device comprising: a detection unit array and a back-end circuit analysis and processing module;

[0006] The detection unit array is provided with a plurality of independent charge input channels in the inner circumferential direction and the outer circumferential direction, respectively. Each charge output channel is used to output a different starting charge pulse signal in the inner circumferential direction and a different ending charge pulse signal in the outer circumferential direction after a charged particle in space is incident at an incident angle θ, and respectively delay and amplify to obtain a corresponding starting pulse signal and ending pulse signal;

[0007] The back-end circuit analysis and processing module is used to collect different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel, and obtain the actual flight time and actual incident azimuth angle time of the charged particle based on the collected different starting pulse signals and ending pulse signals. According to the obtained actual flight time of the charged particle, the composition of the charged particle is obtained, and according to the actual incident azimuth angle 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.

[0008] As one of the improvements to the above technical solution, the detection unit array includes: a particle incident device, an inner circle anode sub-array and an outer circle anode sub-array; the inner circle anode sub-array and the outer circle anode sub-array are concentric circular ring structures, and the particle incident device is covered on the circular ring structure;

[0009] The inner circular anode sub-array comprises a plurality of inner circular anodes distributed in a circular pattern, and a delay line is connected in series between the inner circular anodes. Each inner circular anode serves as a detection unit and independently outputs a starting charge pulse signal of a space-charged particle with an incident angle θ emitted from a particle injection device. Two adjacent inner circular anodes are respectively marked as the head end and the tail end of the inner circular anode sub-array, and a first preamplifier and a second preamplifier are respectively provided thereon for delaying and amplifying the collected starting charge pulse signal to obtain a starting pulse signal A and a starting pulse signal B. Each inner circular anode has its own specific incident angle, and the plurality of inner circular anodes distributed in a circular pattern form a 360-degree incident range.

[0010] The outer circular anode subarray comprises: a plurality of circular anodes distributed circumferentially, with delay lines connected in series between the outer circular anodes. Each outer circular anode acts as a detection unit, independently outputting a termination charge pulse signal for spatially charged particles emitted from a particle injection device at an incident angle θ. Two adjacent outer circular anodes, designated as the head and tail ends of the outer circular anode subarray, are provided with a third preamplifier and a fourth preamplifier, respectively, for delaying and amplifying the collected termination charge pulse signal to produce a termination start pulse signal A and a termination pulse signal B. Each outer circular anode 2 has its own specific incident angle, and the plurality of circularly distributed outer circular anodes form a 360-degree incident range.

[0011] As one of the improvements of the above technical solution, the particle injection device includes: a starting carbon film plate, a terminating carbon film plate, a particle blocking film plate and a microchannel plate;

[0012] The starting carbon film plate is located above the ending carbon film plate, and the two are respectively provided with corresponding inlet and outlet ports, the two are sealed, and a deflection electrode is provided inside. The particle blocking film plate is arranged at the outlet port of the ending carbon film plate and is located above the microchannel plate;

[0013] The acceleration voltage U is added at the entrance of the starting carbon film plate ACC = -15000V, the space charged particles enter from the incident port of the starting carbon film plate, pass through the starting carbon film plate and generate loss energy E loss , and at the same time, secondary electrons are generated; the secondary electrons are deflected by the built-in deflection electrode, pass through the exit of the termination carbon film plate, and are incident on the microchannel plate, generating a starting charge pulse signal; at the same time, after passing through the spatial charged particles of the starting carbon film plate, they directly hit the termination carbon film plate and generate secondary electrons again. After the secondary electrons continue to fly through the particle blocking film plate, they are incident on the microchannel plate, generating a termination charge pulse signal.

[0014] As one of the improvements of the above technical solution, the inner circular anode and the outer circular anode are both delay line anode pieces, and are both made of printed circuit boards.

[0015] As one of the improvements of the above technical solution, the first preamplifier, the second preamplifier, the third preamplifier and the fourth preamplifier are all charge-sensitive amplifiers.

[0016] As one of the improvements of 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.

[0017] As one of the improvements of the above technical solution, the back-end circuit analysis and processing module includes: a signal acquisition unit and a data processing unit;

[0018] The signal acquisition unit is used to respectively acquire different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel;

[0019] 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 collected starting pulse signals and ending pulse signals, obtain the composition of the charged particle based on the obtained actual flight time of the charged particle, and obtain the actual incident azimuth angle of the charged particle based on the actual incident azimuth angle time, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0020] As one of the improvements to the above technical solution, the specific process of the data processing unit is as follows:

[0021] Using a signal acquisition unit to acquire a start pulse signal A, an end pulse signal A, a start pulse signal B, and an end pulse signal B;

[0022] The time difference between the starting pulse signal A and the ending pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the starting pulse signal B and the ending pulse signal B is equal to the second flight time τ2 of the particle;

[0023] The first flight time and the second flight time of the particle are correlated; 0<τ1, τ2<maximum flight time of the ion; Δτ=|τ1-τ2|, and Considered as a valid event

[0024] Determine the actual flight time τ of the particle:

[0025] τ=(τ1+τ2) / 2;

[0026] According to the actual flight time of the particle, the mass-to-charge ratio M / q of the particle is determined:

[0027] M / q=2(E / q+eU ACC -E loss ) / (d / τ) 2

[0028] Where M is the mass of the particle; q is the charge of the particle; E is the incident energy of the particle; e is the electron charge 1.6×10 -19 Coulomb; U ACC is the accelerating voltage; E loss is the loss energy of the particle; d is the flight distance of the particle;

[0029] Measure the time difference τ3 between the start pulse signal A and the start pulse signal B, and the time difference τ4 between the end pulse signal A and the end pulse signal B;

[0030] The correlation analysis of τ3 and τ4 satisfies the minimum incident azimuth time of the particle < τ3, τ4 < the maximum incident azimuth time of the particle, Δτ1 = |τ3-τ4|, and Considered as a valid event;

[0031] Determine the actual incident azimuth time τ of the particle 1 :

[0032] τ 1 =(τ3+τ4) / 2

[0033] According to the determined actual incident azimuth time of the particle, and by using an azimuth time lookup table, the actual incident azimuth of the particle is determined.

[0034] The present invention also provides a method for synchronously measuring particle composition and azimuth angle based on time delay, the method comprising:

[0035] Charged particles in space are incident at an angle of θ, and different starting charge pulse signals are output in the inner circumferential direction and different ending charge pulse signals are output in the outer circumferential direction. The signals are delayed and amplified respectively to obtain corresponding starting pulse signals and ending pulse signals.

[0036] The back-end circuit analysis and processing module collects different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel, and obtains the actual flight time and actual incident azimuth angle time of the charged particle based on the collected different starting pulse signals and ending pulse signals. The composition of the charged particle is obtained based on the obtained actual flight time of the charged particle, and the actual incident azimuth angle of the charged particle is obtained based on the actual incident azimuth angle time, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0037] As one of the improvements to the above technical solution, the back-end circuit analysis and processing module collects different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel, obtains the actual flight time and actual incident azimuth time of the charged particle based on the collected different starting pulse signals and ending pulse signals, obtains the composition of the charged particle based on the obtained actual flight time of the charged particle, and obtains the actual incident azimuth angle of the charged particle based on the actual incident azimuth time, thereby achieving synchronous measurement of the particle composition and incident azimuth angle of the charged particle; the specific process is as follows:

[0038] The signal acquisition unit respectively acquires different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel;

[0039] The data processing unit obtains the actual flight time and the actual incident azimuth angle of the charged particle based on the collected different start pulse signals and end pulse signals, and obtains the composition of the charged particle based on the obtained actual flight time of the charged particle, thereby achieving synchronous measurement of the particle composition and the incident azimuth angle of the charged particle;

[0040] 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;

[0041] The time difference between the starting pulse signal A and the ending pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the starting pulse signal B and the ending pulse signal B is equal to the second flight time τ2 of the particle;

[0042] The first flight time and the second flight time of the particle are correlated; 0<τ1, τ2<maximum flight time of the ion; Δτ=|τ1-τ2|, and Considered as a valid event

[0043] Determine the actual flight time τ of the particle:

[0044] τ=(τ1+τ2) / 2;

[0045] According to the actual flight time of the particle, the mass-to-charge ratio M / q of the particle is determined:

[0046] M / q=2(E / q+eU ACC -E loss ) / (d / τ) 2

[0047] Where M is the mass of the particle; q is the charge of the particle; E is the incident energy of the particle; e is the charge of the particle 1.6×10 -19 Coulomb; U ACC is the accelerating voltage; E loss is the loss energy of the particle; d is the flight distance of the particle;

[0048] Measure the time difference τ3 between the start pulse signal A and the start pulse signal B, and the time difference τ4 between the end pulse signal A and the end pulse signal B;

[0049] The correlation analysis of τ3 and τ4 satisfies the minimum incident azimuth time of the particle < τ3, τ4 < the maximum incident azimuth time of the particle, Δτ1 = |τ3-τ4|, and Considered as a valid event;

[0050] Determine the actual incident azimuth time τ of the particle 1 :

[0051] τ 1 =(τ3+τ4) / 2

[0052] According to the determined actual incident azimuth time of the particle, and by using an azimuth time lookup table, the actual incident azimuth of the particle is determined.

[0053] The beneficial effects of the present invention compared with the prior art are:

[0054] The device of the present invention can solve the technical problem of synchronous measurement of particle composition and azimuth angle in a device during space environment detection, greatly reducing the weight of the instrument and lowering power consumption. It has a wide range of application needs in the field of space detection where resources such as weight and power consumption are tight, especially in the field of deep space detection. In addition, the high-time-precision inner circular anode and outer circular anode used in the present invention are both delayed anode sheets, which can improve the delay time error accuracy caused by inconsistent anode area and printed circuit board layout and wiring to less than 1 nanosecond, greatly improving the particle composition and azimuth angle resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a structural schematic diagram of a synchronous measurement device of particle composition and azimuth angle based on time delay of the present invention;

[0056] Figure 2 It is a structural schematic diagram of a detection unit array of a device for synchronously measuring particle composition and azimuth angle based on time delay of the present invention;

[0057] Figure 3 This is a schematic structural diagram of a hollowed-out middle layer (white) of an inner circular anode of a 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 4 It is a structural schematic diagram of the inner circle anode sub-array of the detection unit array of the synchronous measurement device of particle composition and azimuth angle based on time delay of the present invention;

[0059] Figure 5 1. It is a schematic structural diagram of an outer circular anode sub-array of a 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 6 It is a flow chart of a specific embodiment of a method for synchronously measuring particle composition and azimuth angle based on time delay of the present invention;

[0061] Figure 7 This is a functional block diagram of a device for synchronously measuring particle composition and azimuth angle based on time delay of the present invention, which uses a time measurement FPGA to measure azimuth angle time;

[0062] Figure 8 This is a working mechanism diagram of the time interval measurement of the time measurement FPGA of the synchronous measurement device of the particle composition and azimuth angle based on time delay of the present invention.

[0063] Name of attached figure:

[0064] 1. Inner circle anode 2. Outer circle anode

[0065] 3. Starting carbon film 4. Ending carbon film

[0066] 5. Ion blocking membrane 6. Microchannel plate

[0067] 7. Secondary electrons 8. Secondary electrons

[0068] 9. Deflection electrode DETAILED DESCRIPTION

[0069] The present invention will now be further described with reference to the accompanying drawings and examples.

[0070] The present invention provides a device for synchronously measuring particle composition and azimuth based on time delay, the device comprising: a detection unit array and a back-end circuit analysis and processing module;

[0071] The detection unit array is provided with a plurality of independent charge output channels in the inner circumferential direction and the outer circumferential direction, respectively. Each charge output channel is used to output a different starting charge pulse signal in the inner circumferential direction and a different ending charge pulse signal in the outer circumferential direction after a charged particle in space is incident at an incident angle θ, and amplify them respectively to obtain corresponding starting pulse signals and ending pulse signals;

[0072] The back-end circuit analysis and processing module is used to collect different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel, and obtain the actual flight time and actual incident azimuth angle time of the charged particle based on the collected different starting pulse signals and ending pulse signals. According to the obtained actual flight time of the charged particle, the composition of the charged particle is obtained, and according to the actual incident azimuth angle 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.

[0073] Among them, Figure 1 、 2 As shown in , 3, the detection unit array includes: a particle incident device, an inner circle anode sub-array and an outer circle anode sub-array; the inner circle anode sub-array and the outer circle anode sub-array are concentric circular ring structures, and the particle incident device is covered on the circular ring structure;

[0074] Among them, Figure 4As shown, the inner circular anode sub-array includes a plurality of inner circular anodes 1 distributed in a circular pattern, and a delay line is connected in series between the inner circular anodes 1. Each inner circular anode 1 serves as a detection unit and independently outputs a starting charge pulse signal of a space-charged particle with an incident angle θ emitted from a particle injection device. Two adjacent inner circular anodes 1 are respectively marked as the head end and the tail end of the inner circular anode sub-array, and a first preamplifier and a second preamplifier are respectively provided thereon for delaying and amplifying the collected starting charge pulse signal to obtain a starting pulse signal A and a starting pulse signal B. Each inner circular anode 1 has its own specific incident angle, and the plurality of inner circular anodes 1 distributed in a circular pattern form a 360-degree incident range.

[0075] like Figure 5 As shown, the outer circular anode subarray comprises: a plurality of outer circular anodes 2 distributed circumferentially, with delay lines connected in series between the outer circular anodes 2. Each outer circular anode 2 serves as a detection unit, independently outputting a termination charge pulse signal of a spatially charged particle with an incident angle θ emitted from a particle injection device. Two adjacent outer circular anodes 2 are respectively designated as the head end and the tail end of the outer circular anode subarray, and are provided with a third preamplifier and a fourth preamplifier, respectively, for delaying and amplifying the collected termination charge pulse signal to obtain a termination start pulse signal A and a termination pulse signal B. Each outer circular anode 2 has its own specific incident angle, and the plurality of outer circular anodes 2 distributed circumferentially form a 360-degree incident range.

[0076] The particle injection device includes: a starting carbon film plate 3, a terminating carbon film plate 4, a particle blocking film plate 5 and a microchannel plate 6;

[0077] The starting carbon film plate 3 and the ending carbon film plate 4 both include 1.5-2.0 μg / cm 2 The ultra-thin carbon film and honeycomb stainless steel mesh structure, the specific production method is as follows:

[0078] The ultra-thin carbon film is placed in deionized water and floated on the surface of the deionized water. The ultra-thin carbon film is then picked up using a honeycomb stainless steel mesh structure and fixed on the stainless steel mesh structure to form a starting carbon film plate 3 and a terminating carbon film plate 4.

[0079] The starting carbon film plate 3 is located above the ending carbon film plate 4, and the two are respectively provided with corresponding inlet and outlet ports, the two are sealed, and a deflection electrode 9 is provided inside. The particle blocking film plate 5 is arranged at the outlet port of the ending carbon film plate 4 and is located above the microchannel plate 6;

[0080] The acceleration voltage U is added at the entrance of the starting carbon film plate 3. ACC = -15000V, the space charged particles enter from the incident port of the starting carbon film plate 3, pass through the starting carbon film plate 3 and generate loss energy Eloss , and at the same time, secondary electrons 7 are generated; the secondary electrons 7 are deflected by the built-in deflection electrode 9, pass through the exit of the termination carbon film plate 4, and are incident on the microchannel plate 6, generating a starting charge pulse signal; at the same time, the spatial charged particles passing through the starting carbon film plate 3 fly a distance d, directly hit the termination carbon film plate 4 and generate secondary electrons 8 again, and the 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.

[0081] The deflection electrode 9 is a high-voltage component, surrounded by multiple low-voltage components. These components are isolated using space and polyimide materials to ensure safety. The high-voltage component is loaded with 15,000V, deflecting secondary electrons 7 generated by the starting carbon film 3 onto the MCP. The signal is then collected by the starting anode.

[0082] The inner circular anode 1 and the outer circular anode 2 are both delay line anode pieces, and are both made of printed circuit boards. The time accuracy error of the inner circular anode and the outer circular anode is controlled to be less than 1 nanosecond.

[0083] The first preamplifier, the second preamplifier, the third preamplifier and the fourth preamplifier are all charge-sensitive amplifiers.

[0084] Among them, the structural diagram of the inner circle anode sub-array is as follows: Figure 4 As shown, Figure 4 The inner anode in the figure is the inner circular anode. The inner circular anode subarray includes 16 inner circular anodes, connected end to end. A delay line is connected in series before the inner circular anodes to measure the charge of the initial charge pulse signal generated by the microchannel plate. Inner circular anode 1 serves as the starting end, connected to preamplifier A, which serves as the first preamplifier. Inner circular anode 16 serves as the tail end, connected to preamplifier B, which serves as the second preamplifier. Preamplifiers A and B respectively delay, amplify, and perform analog-to-digital conversion on the incident initial charge pulse signal to generate the corresponding initial digital pulse signals, namely, starting signal A and starting signal B.

[0085] The structure diagram of the outer circular anode sub-array is shown in Figure 5. Figure 5 The outer ring anode in the figure is an outer circular anode. The outer circular anode subarray includes 16 outer ring anodes, which are connected end to end. A delay line is connected in series before the outer ring anodes to measure the charge of the termination charge pulse signal generated by the microchannel plate. Outer ring anode 1 serves as the starting end and is connected to preamplifier A, which serves as the third preamplifier. Outer ring anode 16 serves as the tail end and is connected to preamplifier B, which serves 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.

[0086] In order to amplify the trace charge signal, a highly sensitive preamplifier is required. In order to measure the time of flight, the preamplifier used in the present invention has a very high response speed.

[0087] A copper clad is added to the middle of the annular structure and is connected to the signal ground for signal shielding.

[0088] Wherein, the back-end circuit analysis and processing module includes: a signal acquisition unit and a data processing unit;

[0089] The signal acquisition unit is used to respectively acquire different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel;

[0090] 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 collected starting pulse signals and ending pulse signals, obtain the composition of the charged particle based on the obtained actual flight time of the charged particle, and obtain the actual incident azimuth angle of the charged particle based on the actual incident azimuth angle time, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0091] Specifically, the specific process of the data processing unit is:

[0092] Using a signal acquisition unit to acquire a start pulse signal A, an end pulse signal A, a start pulse signal B, and an end pulse signal B;

[0093] The time difference between the starting pulse signal A and the ending pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the starting pulse signal B and the ending pulse signal B is equal to the second flight time τ2 of the particle;

[0094] The first flight time and the second flight time of the particle are correlated; 0<τ1, τ2<maximum flight time of the ion; Δτ=|τ1-τ2|, and Considered as a valid event

[0095] Determine the actual flight time τ of the particle:

[0096] τ=(τ1+τ2) / 2;

[0097] According to the actual flight time of the particle, the mass-to-charge ratio M / q of the particle is determined:

[0098] M / q=2(E / q+eU ACC -E loss ) / (d / τ) 2

[0099] Where M is the mass of the particle; q is the charge of the particle; E is the incident energy of the particle; e is the charge of the particle 1.6×10 -19 Coulomb; U ACC is the accelerating voltage; E loss is the loss energy of the particle; d is the flight distance of the particle;

[0100] Measure the time difference τ3 between the start pulse signal A and the start pulse signal B, and the time difference τ4 between the end pulse signal A and the end pulse signal B;

[0101] The correlation analysis of τ3 and τ4 satisfies the minimum incident azimuth time of the particle < τ3, τ4 < the maximum incident azimuth time of the particle, Δτ1 = |τ3-τ4|, and Considered as a valid event;

[0102] Determine the actual incident azimuth time τ of the particle 1 :

[0103] τ 1 =(τ3+τ4) / 2

[0104] The actual incident azimuth angle of the particle is determined based on the determined actual incident azimuth angle time and using an azimuth angle time lookup table. The azimuth angle time lookup table is a known table based on a measured azimuth angle time produced according to specific equipment.

[0105] like Figure 6 As shown, Figure 6 This is a block diagram of the time measurement circuit system. In this embodiment, the start signal A and the end signal A are measured by a TDC-GP1 chip to obtain the flight time τ1; the start signal B and the end 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 end signal A and the end 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.

[0106] like Figure 7 As shown in the figure, since the order of start signal A and start signal B is uncertain, and the order of stop signal A and stop signal B is also uncertain, the TDC-GP series chip cannot be used to complete the measurement. Azimuth time measurement is implemented using a time measurement FPGA. To ensure the accuracy of time measurement, the FPGA also has a temperature compensation algorithm to perform temperature correction on the measurement results. Its function and data flow diagram are shown in the figure. Figure 7 As shown, Figure 7A software functional block diagram of a time measurement FPGA is provided. The time measurement function of the FPGA is implemented by internal logic resources. The solution for achieving high-precision time measurement in the FPGA is a method that combines "coarse" counting with "fine" time measurement, wherein the coarse counting is achieved by a counter driven by the clock signal within the FPGA, and the timing clock frequency is 40MHz. Fine time measurement uses a time interpolation method, using delay units (or gate circuits) to accurately phase-shift the input pulse signal, and the relative position of the measured signal on the delay chain is used to determine the slight offset of the input signal relative to the coarse counting clock edge. The FPGA time measurement chip of the present invention can achieve a minimum measurement time length of 3 nanoseconds and a resolution of 300ps.

[0107] Figure 7 Reset in

[0108] Externally input asynchronous signals such as the power-on reset signal need to undergo asynchronous reset synchronous release processing. This way, the designed circuit has more reliable synchronization, which is beneficial for subsequent timing analysis and timing convergence. The maximum clock frequency Fmax of the circuit generated after synthesis will be higher, which is beneficial to improving the working performance of the entire circuit.

[0109] Figure 7 Instruction parsing and control in

[0110] The master FPGA generates control signals, address signals, and data bus signals to read and write to the time measurement FPGA. The time measurement FPGA interprets the master FPGA's bus access. If the access is valid, it analyzes the configured parameters and generates corresponding control signals internally or sends data to other functional modules.

[0111] Figure 7 Time measurement in

[0112] Time measurement is one of the core functions of a time measurement FPGA. This function is implemented using the logic gates within the FPGA chip. In this project, the two digital pulses output by the preamplifier correspond to the τ3 and τ4 channels, respectively. The input signals for the τ3 channel are START_A and START_B, and the input signals for the τ4 channel are STOP_A and STOP_B.

[0113] The START_A signal of the τ3 channel is input_a_st, and the START_B signal is input_a_sp. The STOP_A signal of the τ4 channel 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.

[0114] The time measurement function of the 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 achieved using a counter driven by the FPGA's internal clock signal, with a clock frequency of 42 MHz. In other embodiments, different clock frequencies can be used to achieve varying degrees of time measurement accuracy. Fine time measurement utilizes time interpolation, using delay cells (OR gates) to precisely phase-shift the input pulse signal. The relative position of the signal along the delay chain is measured to determine the slight offset of the input signal relative to the coarse counting clock edge.

[0115] There are two time measurement channels in the time measurement FPGA. Each time measurement channel actually includes two time interpolation time measurement units, that is, there is one time interpolation time measurement unit for the Start signal and the Stop signal respectively.

[0116] According to the resource characteristics of the FPGA chip, an OR gate logic circuit is used to implement the time measurement delay unit. Figure 8 This is a schematic diagram of the logic unit (Versatile) of the ProASIC Plus series FPGA. It can be configured into logic gates (such as OR gate logic gate circuits) to implement delay chain units.

[0117] Figure 7 INL correction in

[0118] Because the delay values ​​of each element in the time measurement delay chain deviate from the average code width (differential nonlinearity, DNL), the accumulation of this DNL leads to integral nonlinearity (INL), which in turn causes errors in the measured time. To achieve the required measurement accuracy, the fine time measurement values ​​must be corrected. This correction method uses a lookup table, known as the INL correction parameter table.

[0119] To this end, during the welding debugging phase, after the time measurement logic is downloaded to the FPGA, a signal generator must be used to generate two pulse signals, which are sent to the Start and Stop interfaces of the time measurement respectively. The frequency of the signal source should be numerically weakly correlated with the frequency of the FPGA input clock crystal oscillator. When the data output by the time measurement reaches a certain statistical value, the raw data is analyzed and processed to obtain the INL value corresponding to each fine counting code. That is, a correction parameter table with a one-to-one correspondence between the fine counting code and the INL value is generated. 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.

[0120] The entire INL parameter correction adopts a pipelined working mode. The 6-bit fine count 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 output as the final correction result DataOut[8:0].

[0121] There are two time measurement channels in the time measurement FPGA, so there are four time measurement modules (Start_A, Start_B, Stop_A, Stop_B). Each time measurement module needs to implement the above Figure 7 The correction function shown in the figure. Because the INL characteristic varies with temperature, it is necessary to pre-test at different temperatures to generate multiple INL tables. During actual operation, the FPGA selects the corresponding INL parameter table for correction based on the temperature measurement results collected by the current temperature acquisition module.

[0122] Figure 7 Temperature measurement in

[0123] A two-channel temperature sensor chip DS18S20Z is installed on the PCB board near the time measurement-FPGA. The time measurement FPGA needs to regularly collect temperature information as the basis for the INL correction module to select the parameter correction table.

[0124] Under normal operating conditions, the DS18S20Z has a minimum temperature measurement accuracy of 0.5°C. When the actual measured temperature is below +40°C, the INL correction step size is set to 8°C. When the actual measured temperature is above +40°C (inclusive), the INL correction step size is set to 4°C. Therefore, based on the actual temperature measurement conditions, the temperature range within the normal range (-40°C to +45°C) is grouped and encoded. When the correction step size is 8°C, the 16 temperature points collected by the DS18S20Z are grouped together. When the correction step size is 4°C, the 8 temperature points collected by the DS18S20Z are grouped together. This serves as the basis for selecting the corresponding INL correction parameter table in the subsequent INL correction module.

[0125] Figure 7 Data output

[0126] The data output function is mainly divided into two parts. One function is to return the corresponding internal read register value to the master FPGA based on the read address information of the current master FPGA operation. The other function is to store the time interval measurement value in the internal FIFO and notify the master FPGA to read it by generating an interrupt signal.

[0127] The following details the output processing of the time interval measurement value. First, after the time measurement-FPGA receives the Start (or Stop) signal on each time measurement channel, it waits for the next paired Start (or Stop) signal and writes the time interval measurement value (TSTART_B - TSTART_A or TSTART_A - TSTART_B) between the rising edges of the two signals to the first-in-first-out buffer (FIFO) for reading by the master FPGA.

[0128] like Figure 8 As shown in the figure, 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, which is discarded during the measurement process. The Start_A signal can precede or follow 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 comes after, the time interval measurement value is positive; otherwise, it is negative. The principle of time interval measurement for the Stop signal is the same as that for the Start signal.

[0129] The measurement device of the present invention can measure time within a range of -150ns to +150ns. That is, each time the first Start or Stop signal arrives, the time measurement-FPGA only searches for the first matching signal within the time range of 0ns to 150ns, discarding any Start or Stop signals outside this range. After each Start (or Stop) signal is received, the time measurement also discards any subsequent Start (or Stop) signals during this measurement. The sign of the time measurement range indicates that the sign is positive when the Start signal arrives first and negative when the Stop signal arrives first.

[0130] After each time measurement channel receives a Start (or Stop) signal, it waits for the next paired Start (or Stop) signal and writes the time interval between the rising edges of the two signals to the buffer FIFO for the master FPGA to read. Simultaneously, an interrupt signal (active high) is sent to notify the master FPGA to read the data. After the master FPGA responds to the interrupt signal and reads the FIFO, it automatically clears the interrupt signal and prepares for the next time measurement.

[0131] The present invention also provides a method for synchronously measuring particle composition and azimuth angle based on time delay, the method comprising:

[0132] Charged particles in space are incident at an angle of θ, and different starting charge pulse signals are output in the inner circumferential direction and different ending charge pulse signals are output in the outer circumferential direction. The signals are delayed and amplified respectively to obtain corresponding starting pulse signals and ending pulse signals.

[0133] The back-end circuit analysis and processing module collects different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel, and obtains the actual flight time and actual incident azimuth angle time of the charged particle based on the collected different starting pulse signals and ending pulse signals. The composition of the charged particle is obtained based on the obtained actual flight time of the charged particle, and the actual incident azimuth angle of the charged particle is obtained based on the actual incident azimuth angle time, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

[0134] Specifically, the signal acquisition unit respectively acquires different start pulse signals output in the inner circumferential direction and different end pulse signals output in the outer circumferential direction for each charge output channel;

[0135] The data processing unit obtains the actual flight time and the actual incident azimuth angle of the charged particle based on the collected different start pulse signals and end pulse signals, and obtains the composition of the charged particle based on the obtained actual flight time of the charged particle, thereby achieving synchronous measurement of the particle composition and the incident azimuth angle of the charged particle;

[0136] 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;

[0137] The time difference between the starting pulse signal A and the ending pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the starting pulse signal B and the ending pulse signal B is equal to the second flight time τ2 of the particle;

[0138] The first flight time and the second flight time of the particle are correlated; 0<τ1, τ2<maximum flight time of the ion; Δτ=|τ1-τ2|, and Considered as a valid event.

[0139] Determine the actual flight time τ of the particle:

[0140] τ=(τ1+τ2) / 2;

[0141] According to the actual flight time of the particle, the mass-to-charge ratio M / q of the particle is determined:

[0142] M / q=2(E / q+eU ACC -E loss ) / (d / τ)2

[0143] Where M is the mass of the particle; q is the charge of the particle; E is the incident energy of the particle; e is the charge of the particle 1.6×10 -19 Coulomb; U ACC is the accelerating voltage; E loss is the loss energy of the particle; d is the flight distance of the particle;

[0144] Measure the time difference τ3 between the start pulse signal A and the start pulse signal B, and the time difference τ4 between the end pulse signal A and the end pulse signal B;

[0145] The correlation analysis of τ3 and τ4 satisfies the minimum incident azimuth time of the particle < τ3, τ4 < the maximum incident azimuth time of the particle, Δτ1 = |τ3-τ4|, and Considered as a valid event;

[0146] Determine the actual incident azimuth time τ of the particle 1 :

[0147] τ 1 =(τ3+τ4) / 2

[0148] According to the determined actual incident azimuth time of the particle, and by using an azimuth time lookup table, the actual incident azimuth of the charged particle is determined.

[0149] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art 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 are intended to be encompassed by the claims of the present invention.

Claims

1. A device for synchronously measuring particle composition and azimuth based on time delay, characterized in that: The device comprises: a detection unit array and a back-end circuit analysis and processing module; The detection unit array is provided with a plurality of independent charge input channels in the inner circumferential direction and the outer circumferential direction, respectively. Each charge output channel is used to output a different starting charge pulse signal in the inner circumferential direction and a different ending charge pulse signal in the outer circumferential direction after a charged particle in space is incident at an incident angle θ, and respectively delay and amplify to obtain a corresponding starting pulse signal and ending pulse signal; The back-end circuit analysis and processing module is used to collect different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel, obtain the actual flight time and actual incident azimuth time of the charged particle based on the collected different starting pulse signals and ending pulse signals, obtain the composition of the charged particle based on the obtained actual flight time of the charged particle, and obtain the actual incident azimuth angle of the charged particle based on the actual incident azimuth time, thereby achieving synchronous measurement of the particle composition and incident azimuth angle of the charged particle; The detection unit array includes: a particle incident device, an inner circle anode sub-array and an outer circle anode sub-array; the inner circle anode sub-array and the outer circle anode sub-array are concentric circular ring structures, and the particle incident device is covered on the circular ring structure; The inner circular anode sub-array comprises a plurality of inner circular anodes (1) distributed in a circular pattern, and a delay line is connected in series between the inner circular anodes (1), and each inner circular anode (1) serves as a detection unit and independently outputs a starting charge pulse signal of a space charged particle with an incident angle θ emitted from a particle injection device; two adjacent inner circular anodes (1) are respectively recorded as the head end and the tail end of the inner circular anode sub-array, and a first preamplifier and a second preamplifier are respectively provided thereon for respectively delaying and amplifying the collected starting charge pulse signal to obtain a starting pulse signal A and a starting pulse signal B; wherein each inner circular anode (1) has its own specific incident angle, and the plurality of inner circular anodes (1) distributed in a circular pattern form an incident range of 360 degrees; The outer circular anode subarray comprises: a plurality of outer circular anodes (2) distributed in a circular pattern, wherein a delay line is connected in series between the outer circular anodes (2), and each outer circular anode (2) serves as a detection unit and independently outputs a termination charge pulse signal of a space charged particle with an incident angle θ emitted from a particle incident device; two adjacent outer circular anodes (2) are respectively marked as the head end and the tail end of the outer circular anode subarray, and a third preamplifier and a fourth preamplifier are respectively arranged thereon for respectively delaying and amplifying the collected termination charge pulse signal to obtain a termination start pulse signal A and a termination pulse signal B; wherein each outer circular anode (2) has its own specific incident angle, and the plurality of outer circular anodes (2) distributed in a circular pattern form an incident range of 360 degrees.

2. The device for synchronously measuring particle composition and azimuth angle based on time delay according to claim 1, characterized in that: The particle injection device comprises: a starting 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 are respectively provided with corresponding inlet and outlet ports, the two are sealed, and a deflection electrode (9) is provided inside. The particle blocking film plate (5) is provided at the outlet port of the ending carbon film plate (4) and is located above the microchannel (6) plate; An acceleration voltage U is added at the incident port of the starting carbon film plate (3). ACC =-15000V, the space charged particles enter from the incident port of the starting carbon film plate (3), pass through the starting carbon film plate (3) and generate loss energy E loss , and simultaneously generates a secondary electron (7); the secondary electron (7) is deflected by the built-in deflection electrode (9), passes through the exit port of the termination carbon film plate (4), and is incident on the microchannel plate (6), generating a starting charge pulse signal; at the same time, after passing through the spatial charged particle flight distance of the starting carbon film plate (3), it directly hits the termination carbon film plate (4) and generates a secondary electron (8) again, and the secondary electron (8) continues to fly through the particle blocking film plate (5) and is incident on the microchannel plate (6), generating a termination charge pulse signal.

3. The device for synchronously measuring particle composition and azimuth angle based on time delay according to claim 1, characterized in that: The inner circular anode (1) and the outer circular anode (2) are both delay line anode pieces, and are both made of printed circuit boards.

4. The device for synchronously measuring particle composition and azimuth angle based on time delay according to claim 1, characterized in that: The first preamplifier, the second preamplifier, the third preamplifier and the fourth preamplifier are all charge-sensitive amplifiers.

5. The device for synchronously measuring particle composition and azimuth angle based on time delay according to claim 1, characterized in that: A copper cladding is added to the middle of the circular ring structure, and the copper cladding is connected to the signal ground.

6. The device for synchronously measuring particle composition and azimuth angle based on time delay according to claim 1, characterized in that: 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 respectively acquire different starting pulse signals output in the inner circumferential direction and different ending pulse signals output 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 collected starting pulse signals and ending pulse signals, obtain the composition of the charged particle based on the obtained actual flight time of the charged particle, and obtain the actual incident azimuth angle of the charged particle based on the actual incident azimuth angle time, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

7. The device for synchronously measuring particle composition and azimuth angle based on time delay according to claim 6, characterized in that: The specific process of the data processing unit is as follows: Using a signal acquisition unit to acquire a start pulse signal A, an end pulse signal A, a start pulse signal B, and an end pulse signal B; The time difference between the starting pulse signal A and the ending pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the starting pulse signal B and the ending pulse signal B is equal to the second flight time τ2 of the particle; The first flight time and the second flight time of the particle are correlated; 0<τ1, τ2<maximum flight time of the ion; Δτ=|τ1-τ2|, and Considered as a valid event; Determine the actual flight time τ of the particle: τ=(τ1+τ2) / 2; According to the actual flight time of the particle, the mass-to-charge ratio M / q of the particle is determined: M / q=2(E / q+eU ACC -AND loss ) / (d / τ) 2 Where M is the mass of the particle; q is the charge of the particle; E is the incident energy of the particle; e is the charge of the electron 1.6×10 -19 Coulomb; U ACC is the accelerating voltage; E loss is the loss energy of the particle; d is the flight distance of the particle; Measure the time difference τ3 between the start pulse signal A and the start pulse signal B, and the time difference τ4 between the end pulse signal A and the end pulse signal B; The correlation analysis of τ3 and τ4 satisfies the minimum incident azimuth time of the particle < τ3, τ4 < the maximum incident azimuth time of the particle, Δτ1 = |τ3-τ4|, and Considered as a valid event; Determine the actual incident azimuth time τ of the particle 1 : t 1 =(τ3+τ4) / 2 According to the determined actual incident azimuth time of the particle, and by using an azimuth time lookup table, the actual incident azimuth of the charged particle is determined.

8. A method for synchronously measuring particle composition and azimuth based on time delay, the method being implemented based on the synchronous measurement device for particle composition and azimuth based on time delay according to any one of claims 6 to 7, characterized in that: The method includes: Charged particles in space are incident at an angle of θ, and different starting charge pulse signals are output in the inner circumferential direction and different ending charge pulse signals are output in the outer circumferential direction. The signals are delayed and amplified respectively to obtain corresponding starting pulse signals and ending pulse signals. The back-end circuit analysis and processing module collects different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel, and obtains the actual flight time and actual incident azimuth angle time of the charged particle based on the collected different starting pulse signals and ending pulse signals. The composition of the charged particle is obtained based on the obtained actual flight time of the charged particle, and the actual incident azimuth angle of the charged particle is obtained based on the actual incident azimuth angle time, thereby realizing the synchronous measurement of the particle composition and incident azimuth angle of the charged particle.

9. The method for synchronously measuring particle composition and azimuth angle based on time delay according to claim 8, characterized in that: The back-end circuit analysis and processing module collects different start pulse signals output in the inner circumferential direction and different end pulse signals output in the outer circumferential direction for each charge output channel, obtains the actual flight time and actual incident azimuth time of the charged particle based on the collected different start pulse signals and end pulse signals, obtains the composition of the charged particle based on the obtained actual flight time of the charged particle, and obtains the actual incident azimuth angle of the charged particle based on the actual incident azimuth time, thereby achieving synchronous measurement of the particle composition and incident azimuth angle of the charged particle; the specific process is as follows: The signal acquisition unit respectively acquires different starting pulse signals output in the inner circumferential direction and different ending pulse signals output in the outer circumferential direction for each charge output channel; The data processing unit obtains the actual flight time and the actual incident azimuth angle of the charged particle based on the collected different start pulse signals and end pulse signals, and obtains the composition of the charged particle based on the obtained actual flight time of the charged particle, thereby achieving synchronous measurement of the particle composition and the 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 starting pulse signal A and the ending pulse signal A is equal to the first flight time τ1 of the particle, and the time difference between the starting pulse signal B and the ending pulse signal B is equal to the second flight time τ2 of the particle; The first flight time and the second flight time of the particle are correlated; 0<τ1, τ2<maximum flight time of the ion; Δτ=|τ1-τ2|, and Considered as a valid event; Determine the actual flight time τ of the particle: τ=(τ1+τ2) / 2; According to the actual flight time of the particle, the mass-to-charge ratio M / q of the particle is determined: M / q=2(E / q+eU ACC -AND loss ) / (d / τ) 2 Where M is the mass of the particle; q is the charge of the particle; E is the incident energy of the particle; e is the charge of the particle 1.6×10 -19 Coulomb; U ACC is the accelerating voltage; E loss is the loss energy of the particle; d is the flight distance of the particle; Measure the time difference τ3 between the start pulse signal A and the start pulse signal B, and the time difference τ4 between the end pulse signal A and the end pulse signal B; The correlation analysis of τ3 and τ4 satisfies the minimum incident azimuth time of the particle < τ3, τ4 < the maximum incident azimuth time of the particle, Δτ1 = |τ3-τ4|, and Considered as a valid event; Determine the actual incident azimuth time τ of the particle 1 : t 1 =(τ3+τ4) / 2 According to the determined actual incident azimuth time of the particle, and by using an azimuth time lookup table, the actual incident azimuth of the charged particle is determined.

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