A full-process physical simulation method and platform for charged particle waveform acquisition systems

Abstract

This invention discloses a full-process physical simulation method and platform for a charged particle waveform acquisition system, used to provide waveform datasets of charged particles. The method includes: using the high-energy physics simulation software Geant4 for particle simulation and energy deposition calculation, outputting energy deposition data including different depth positions; based on the energy deposition data, using the silicon microstrip detector simulation software WeightField2 for carrier generation and transport simulation, outputting a detector induced current map; and based on the detector induced current map, using LTSpice software to simulate the preamplifier circuit, outputting the complete output waveform of the charged particles. This invention provides a low-cost, high-efficiency solution, enabling particle identification algorithms to be optimized and trained with richer waveform data. It effectively overcomes the problems of insufficient sample size and high experimental costs in existing technologies, improving the accuracy and practicality of charged particle identification.

Description

Technical Field

[0001] This invention belongs to the fields of space environment detection and nuclear physics, and in particular relates to a full-process physical simulation method and platform for a charged particle waveform acquisition system. Background Technology

[0002] Currently, the application of pulse waveform analysis in charged particle identification is transitioning from traditional methods that rely solely on waveform amplitude or rise time to methods that utilize neural networks for comprehensive waveform feature extraction before identification. However, these experimental data-based waveform acquisition methods have significant shortcomings in several aspects:

[0003] The high cost of waveform data acquisition stems from significant human, financial, and time costs: Existing research largely relies on experimental waveform data, which typically originates from expensive experimental equipment such as tandem accelerator plasma irradiation sources and vacuum chambers. This requires a large amount of high-precision experimental equipment, including detectors with different parameters, low-noise preamplifiers, low-latency main amplifiers, high-sampling-rate rapid acquisition devices, and interference-resistant shielded cables. Furthermore, experimental procedures are complex and time-consuming, usually requiring meticulous debugging and optimization by specialized personnel. Due to the cumbersome process of changing sources in tandem accelerators, waveforms of only one or two types of particles can typically be acquired per day. To obtain comprehensive and accurate waveform data, experiments often require repeated operations, each consuming substantial time, manpower, and financial resources. Especially in practical applications, certain particle types or particles at specific energy levels are difficult to generate or capture, further increasing the difficulty and cost of experiments. Therefore, acquiring experimental waveform data is not only time-consuming and costly but also involves significant investment in personnel and equipment, limiting the efficiency and sustainability of research.

[0004] Limited sample size and narrow coverage: Existing studies typically use waveform data from a single source with limited sample sizes. For example, some studies only use waveforms of alpha particles and protons with single energies. These two charged particles differ significantly in energy and waveform shape, making it difficult to adequately support the training of backend particle identification algorithms. In fact, as atomic numbers increase, the waveforms produced by heavy ions reacting with detectors become increasingly similar, especially for isotopes (due to the difficulty of isotope production in tandem accelerators), where waveform differences are often very subtle, making particle identification extremely difficult. Due to the limitations of these waveform samples, particle identification algorithms may experience data bias during training, failing to comprehensively represent the response waveform characteristics of different particles under various conditions, thus affecting the accuracy and robustness of the algorithm. Therefore, to optimize particle identification algorithms, it is necessary to collect more comprehensive and sufficient waveform data to cover a wider range of particle types and conditions.

[0005] Interference from experimental conditions on waveform data: Experimental conditions have a significant impact on the acquired waveform data. For example, noise interference in the laboratory environment (such as whether the vacuum level of the detector environment is sufficient, or the interference of the kilovolt-level high voltage of the tandem accelerator on the signals of cables, amplifiers, and other equipment) may lead to instability or data errors in the experimental results. These environmental factors may negatively affect the accuracy of the waveform, thereby affecting the effectiveness and reliability of the particle identification algorithm.

[0006] Given the shortcomings of existing technologies, such as high cost of acquiring waveform data, high manpower, financial and time costs, limited sample size and narrow coverage, and interference from experimental conditions on waveform data, there is an urgent need for a full-process physical simulation method for charged particle waveform acquisition systems, from detectors to electronics. Summary of the Invention

[0007] This invention proposes a comprehensive physical simulation method and platform covering the entire process from detectors to electronics. This method enables the generation of large amounts of high-quality waveform data without relying on expensive and time-consuming experimental processes. Compared to traditional methods that depend on experimental data, this invention provides a low-cost, high-efficiency solution, allowing particle identification algorithms to be optimized and trained with richer waveform data support. The waveform dataset generated by the simulation platform effectively overcomes the problems of insufficient sample size and high experimental costs in existing technologies, thereby improving the accuracy and practicality of charged particle identification and providing a dataset for charged particle identification technology based on pulse waveform analysis.

[0008] In view of this, the present invention proposes a full-process physical simulation method for a charged particle waveform acquisition system, which provides a waveform dataset of charged particles, including:

[0009] Step 1) Use the high-energy physics simulation software Geant4 to perform particle simulation and energy deposition calculation, and output energy deposition data including different depth locations;

[0010] Step 2) Based on the energy deposition data, the carrier generation and transport simulation was performed using the silicon microstrip detector simulation software WeightField2, and the detector induced current diagram was output.

[0011] Step 3) Based on the detector's induced current diagram, use LTSpice software to simulate the preamplifier circuit and output the complete waveform of the charged particle.

[0012] Preferably, the full-process physical simulation includes: ionization process, plasma erosion effect, carrier transport effect, detector induced charge and preamplifier voltage waveform.

[0013] Preferably, step 1) includes:

[0014] Step 1-1) Use the high-energy physics simulation software Geant4 to set the geometric parameters of the detector and the relevant properties of the particle source;

[0015] Steps 1-2) Select a physical model to describe the interaction between the particle and the detector;

[0016] Steps 1-3) Perform irradiation simulation of the particle source and statistically analyze the energy deposition caused by different particles in the silicon detector;

[0017] Steps 1-4) Obtain energy deposition data at different depths in micrometers and output it in CSV format.

[0018] Preferably, the geometric parameters of the detector in step 1-1) include: a nanoscale aluminum metallization layer and a micrometer-scale silicon layer; the relevant properties of the particle source include: the type and energy of the particles to be simulated.

[0019] Preferably, step 2) includes:

[0020] Step 2-1) Use the silicon microstrip detector simulation software WeightField2 to read the energy deposition data output by the high-energy physics simulation software Geant4, and calculate the number of electron-hole pairs generated at each location of the detector.

[0021] Step 2-2) Combining carrier transport effect and plasma erosion effect, simulate the process of electron-hole pair movement in silicon detector;

[0022] Steps 2-3) Calculate the magnitude and changes of the induced current on the two plates of the detector, and output the induced current diagram of the detector.

[0023] Preferably, step 3) includes:

[0024] Based on the detector's induced current diagram, and considering the resistive input impedance and high gain characteristics, a preamplifier circuit model was established using LTSpice software.

[0025] By adjusting the circuit parameters, simulating and optimizing the preamplifier circuit model, and reducing the distortion introduced by the circuit, an optimized preamplifier circuit is obtained, which outputs a complete waveform of charged particles.

[0026] Preferably, the circuit parameters include gain and frequency response.

[0027] On the other hand, the present invention provides a full-process physical simulation platform for a charged particle waveform acquisition system, the platform comprising:

[0028] The ionization process simulation module is used to perform particle simulation and energy deposition calculations using the high-energy physics simulation software Geant4, and outputs energy deposition data at different depths.

[0029] The carrier generation and transport simulation module is used to simulate carrier generation and transport using the silicon microstrip detector simulation software WeightField2 based on energy deposition data, and outputs the detector induced current diagram.

[0030] The charged particle waveform output module is used to simulate the preamplifier circuit using LTSpice software based on the detector's induced current diagram, and output the complete waveform of the charged particle.

[0031] Compared with the prior art, the advantages of the present invention are:

[0032] This platform enables the generation of large amounts of high-quality waveform data without relying on expensive and time-consuming experimental processes. Compared to traditional methods that depend on experimental data, this invention provides a low-cost, high-efficiency solution, allowing particle identification algorithms to be optimized and trained with richer waveform data support. The waveform dataset generated by the simulation platform effectively overcomes the problems of insufficient sample size and high experimental costs in existing technologies, thereby improving the accuracy and practicality of charged particle identification.

[0033] This application primarily utilizes Geant4 to WeightField2 to LTSpice to simulate the entire physical process of charged particle waveform acquisition from ion irradiation, detectors to electronics, resulting in efficient data generation, low manpower, financial and time costs, broad coverage, freedom from experimental condition interference, high scalability, guaranteed data quality, and data diversity. Attached Figure Description

[0034] Figure 1 This is a schematic diagram showing the conical or cylindrical shape of electron-hole pairs obtained during the ionization process.

[0035] Figure 2 This is a flowchart of the technical solution of the present invention;

[0036] Figure 3 shows the ionization energy loss diagrams obtained from Geant4 software. In Figure 3(a), H-2MeV is shown; in Figure 3(b), H-2.8MeV is shown; in Figure 3(c), He-2.8MeV is shown; and in Figure 3(d), He-4.2MeV is shown.

[0037] Figure 4 This is the detector induced current graph output by WeightField2 software;

[0038] Figure 5This is the voltage waveform of the preamp output obtained from LTspice software. Detailed Implementation

[0039] 1. Principle

[0040] This invention primarily targets a charged particle waveform acquisition system encompassing ion irradiation, detector, and electronics. It simulates and reproduces the entire physical process on a PC, obtaining complete detector output waveforms under different conditions. The complete physical process includes five parts: ionization, plasma erosion effect, carrier transport effect, detector induced charge, and preamplifier voltage waveform.

[0041] Ionization Process: During ion irradiation, when a charged particle passes through a silicon detector, it transfers energy to electrons in the material, leaving an ionization track behind it. According to the classical atomic model, when a positively or negatively charged incident particle passes near a target atom, the electrons of the target atom are attracted or repelled by Coulomb forces, thus gaining energy. The energy loss caused by the inelastic collision between the incident charged particle and the target atom's electrons is called ionizing radiation energy loss, also known as ionization energy loss. If the energy gained by the electron exceeds its binding energy with the atomic orbital, it will escape the nucleus and become a free electron, making the atom a positive ion. In practical materials, this ionization process manifests as electrons in the valence band gaining energy to enter the conduction band, leaving holes in the valence band, i.e., forming electron-hole pairs. The energy required to generate an electron-hole pair in a semiconductor is related to the semiconductor's band gap; in silicon, 3.6 eV of energy is required to generate one electron-hole pair.

[0042] Plasma erosion effect: Electron-hole pairs obtained through the ionization process generally take the form of cones or cylinders, such as... Figure 1 As shown, the plasma begins to erode from the outer surface, and charge carriers (i.e., electrons and holes) continuously migrate away from the surface until the internal electric field is the same as the external electric field. At this point, the entire plasma will disintegrate, and electrons and holes will no longer be restricted and can move freely.

[0043] Charge carrier transport effect: In semiconductor detectors, free electrons and holes migrate along the direction of the electric field within the material due to the applied electric field. Electron-hole pairs generated during ionization begin to migrate towards the electrodes under the influence of the applied electric field; electrons move towards the anode (positive electrode), while holes move towards the cathode (negative electrode). During this process, the migration speed of electrons and holes is affected by the electron mobility and hole mobility of the material. Semiconductor materials such as silicon typically have higher electron mobility than hole mobility, therefore electrons usually migrate faster in the electric field. Furthermore, the strength and direction of the electric field have a significant impact on the transport path and efficiency of charge carriers. When the applied electric field is strong, charge carriers migrate towards the electrodes more quickly, but this may also be accompanied by a higher recombination rate, causing some electrons and holes to recombine and lose their effective current contribution.

[0044] The process of induced charge and current in a detector: When freely moving electrons and holes reach the electrodes of the detector, they form induced charges on the electrodes. The accumulation of charge generates a current pulse, which represents the detector's response to the incident particle event. The magnitude of the induced current is closely related to the energy and type of the incident particle. The amount of charge generated by electrons and holes during migration determines the amplitude of the output signal, thus reflecting the energy and properties of the incident particle. In semiconductor detectors, the induced current typically presents as a brief pulse signal. The rise and fall times of this signal are closely related to the carrier migration time, recombination time, and the strength of the applied electric field.

[0045] Preamplifier voltage waveform: Because the pulse waveform output by the semiconductor detector is extremely fast (on the order of ps) and small (on the order of mV), existing high-speed acquisition equipment cannot accurately acquire such signals. Therefore, a preamplifier must be used to amplify the waveform. During the preamplifier amplification process, the signal waveform may undergo a certain degree of distortion, mainly due to the characteristics of the circuit (such as gain, bandwidth, response time, etc.) and the current output characteristics of the detector. Therefore, this part needs to be taken into account when processing high-frequency or ultra-small amplitude signals.

[0046] 2. Plan

[0047] This technical solution provides a full-process simulation platform for the physical processes of charged particle waveform acquisition, from ion irradiation and detectors to electronics. It primarily utilizes three software programs: Geant4, WeightField2, and LTSpice. The specific technical solution flow is as follows: Figure 2WeightField2 is a silicon microstrip detector simulation software developed in recent years. It can calculate plasma erosion effects, carrier transport effects, and induced charges on the detector's two plates. Then, it can be used in conjunction with LTSpice to simulate the preamplifier circuit. However, WF2 can only calculate based on the average energy loss of the minimum ionized particle. Therefore, Geant4 is needed to perform physical simulations of different incident particles, silicon detectors, and laboratory environments to obtain accurate energy loss at different locations of the detector.

[0048] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0049] Example 1

[0050] Embodiment 1 of the present invention proposes a full-process physical simulation method from detector to electronics, the workflow of which can be roughly divided into the following three steps:

[0051] Step 1: Perform particle simulation and energy deposition calculations using Geant4.

[0052] Geant4 is a high-energy physics simulation software that can perform simulations based on user-defined input parameters (such as detector materials, geometry, particle source properties, etc.) and output requirements (such as particle energy deposition, emitted particle information, particle trajectory, etc.). We use Geant4 to simulate ion irradiation processes in a real environment to calculate ionization effects and energy losses inside the detector. Specific steps are illustrated below:

[0053] 1) Set the detector's geometric parameters, which typically include a 100-nanometer-thick aluminum metallization layer and a 300-micrometer-thick silicon layer, as well as the relevant properties of the particle source (such as particle type and energy).

[0054] 2) Select an appropriate physical model to describe the interaction between the particle and the detector. In Example 1, the physical model we used is Electromagnetic-FTFP_BERT.

[0055] 3) Irradiation simulations of particle sources were performed, and the energy deposition caused by different particles (such as MeV-level charged ions) in the silicon detector was statistically analyzed, as shown in Figure 3. Among them, Figure 3(a) is H-2MeV, Figure 3(b) is H-2.8MeV, Figure 3(c) is He-2.8MeV, and Figure 3(d) is He-4.2MeV.

[0056] 4) The results output by Geant4 will include energy deposition data at different depths in micrometers, and will be output in CSV format for subsequent processing.

[0057] These outputs provide WeightField2 with the necessary energy deposition information for further carrier simulations.

[0058] Step 2: Simulate carrier generation and transport using WeightField2

[0059] WeightField2 is a recently developed simulation software for silicon microstrip detectors. It simulates electron-hole pairs generated from ionization processes and tracks their movement within the silicon detector. Based on energy deposition data obtained from Geant4, it calculates the amount of charge generated at different locations and simulates the movement of these electron-hole pairs, influenced by carrier transport and plasma erosion effects. The simulation flow of WeightField2 in this step is as follows:

[0060] 1) Read the energy deposition data output by Geant4 and calculate the number of electron-hole pairs generated at each location of the detector based on this data.

[0061] 2) Simulate the process of these electron-hole pairs moving in the silicon detector, taking into account carrier transport effects (such as carrier mobility and diffusion) and plasma erosion effects (such as charge drift on the detector surface).

[0062] 3) By simulating these effects, WeightField2 can calculate the magnitude and changes of the induced current on the detector's two plates, providing data support for subsequent waveform acquisition, such as... Figure 4 .

[0063] 4) WeightField2's software interface (GUI) allows for flexible detector parameter settings and also supports more accurate physical process simulations by modifying the source code to meet specific experimental needs.

[0064] Step 3: Simulate the preamplifier circuit and waveform acquisition using LTSpice.

[0065] In particle detector systems, the induced current signal needs to be amplified and processed by a preamplifier before subsequent waveform acquisition and analysis. Since the response of the preamplifier circuit may introduce some distortion into the acquired signal, LTSpice simulation software is required to model and optimize the circuit to ensure the accuracy of waveform acquisition. Specific steps include:

[0066] 1) Use LTSpice to build a preamplifier circuit model, which is usually designed based on resistive input impedance and high gain characteristics.

[0067] 2) By simulating and analyzing the influence of the circuit on the detector output signal, the influence of different circuit parameters (such as gain, frequency response, etc.) on the acquired waveform is studied.

[0068] 3) Simulate and optimize the circuit to ensure that the final waveform accurately reflects the detector's output current and reduce distortion introduced by the circuit.

[0069] 4) The LTSpice simulation results can be used to adjust the parameters of the preamplifier circuit to adapt to different experimental conditions, ensuring the stability and accuracy of the system, such as... Figure 5 .

[0070] This technical solution combines Geant4, WeightField2, and LTSpice to simulate the entire process from ion irradiation, carrier generation and transport to waveform acquisition in the preamplifier circuit. Each simulation stage provides the necessary data support for the next stage, ensuring that the entire system accurately reflects the response of charged particles in the silicon detector. Through this process, we can obtain high-quality particle detection signals and provide a reliable foundation for subsequent data analysis and processing.

[0071] Example 2

[0072] Embodiment 2 of the present invention proposes a full-process physical simulation platform for a charged particle waveform acquisition system, implemented based on the method of Embodiment 1. The platform includes:

[0073] The ionization process simulation module is used to perform particle simulation and energy deposition calculation using the high-energy physics simulation software Geant4, and outputs energy deposition data at different depths.

[0074] The carrier generation and transport simulation module is used to simulate carrier generation and transport using the silicon microstrip detector simulation software WeightField2 based on energy deposition data, and outputs the detector induced current diagram.

[0075] The charged particle waveform output module is used to simulate the preamplifier circuit using LTSpice software based on the detector's induced current diagram, and output the complete waveform of the charged particle.

[0076] Innovation points:

[0077] 1) Construction of a full-process physical simulation platform

[0078] This invention proposes a complete physical simulation process from detector to electronics, systematically simulating the response process of charged particles in the detector, including the interaction between particles and detector, signal processing of electronic devices, waveform generation and acquisition, etc. This simulation platform can accurately simulate the waveform response of particles under various conditions without the support of actual experimental hardware, filling the limitations of traditional experimental methods in waveform data acquisition.

[0079] 2) Reduce experimental costs and improve efficiency

[0080] Compared to traditional experimental methods, this invention replaces the expensive and time-consuming experimental process with physical simulation. Data acquisition no longer relies on high-precision physical equipment (such as tandem accelerators, vacuum chambers, detectors, etc.), reducing costly equipment investment and complex experimental procedures. Simultaneously, the simulation platform can efficiently generate large-scale waveform datasets, significantly improving data acquisition efficiency.

[0081] 3) Diverse waveform data generation and extensive sample coverage

[0082] The simulation platform of this invention can generate waveform data under different particle types, energy levels, and experimental conditions, avoiding the problems of insufficient sample size and narrow coverage in existing studies. Through the simulation platform, waveforms of various particles, from light particles to heavy ions, can be simulated, covering different energy ranges, particle types, and their corresponding waveform characteristics. Especially for particles that are difficult to obtain experimentally (such as isotopes or high-energy particles), the simulation platform can effectively fill data gaps. The simulation platform has high scalability and flexibility, allowing for flexible adjustment of parameters such as particle type, energy range, and detector characteristics to generate waveform data under specific conditions according to different research needs and experimental conditions. Furthermore, the platform can simulate various experimental settings, including different detector layouts, electronic configurations, and signal acquisition methods, meeting the needs of various application scenarios.

[0083] 4) Reduce the influence of experimental conditions

[0084] In traditional experiments, waveform data is often affected by various unstable factors such as experimental environment noise and equipment interference, which limits the accuracy and reliability of the data. This invention simulates the entire process of particle-detector interaction, and can control experimental parameters, environmental conditions, and noise interference, thereby avoiding the interference of environmental conditions on the data results.

[0085] 5) Supports the optimization and training of particle identification algorithms.

[0086] This invention utilizes a waveform dataset generated through a simulation platform, which effectively supports the optimization of particle identification algorithms based on neural networks and other methods. Compared to traditional methods that rely solely on simple features such as waveform amplitude and rise time, the simulation platform can generate more complex and richer waveform data, enabling neural networks to extract more comprehensive waveform features. This data-driven approach provides particle identification algorithms with more dimensional training data, contributing to improved identification accuracy.

[0087] 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 full-process physical simulation method for a charged particle waveform acquisition system, used to provide a waveform dataset of charged particles, including: Step 1) Use the high-energy physics simulation software Geant4 to perform particle simulation and energy deposition calculation, and output energy deposition data including different depth locations; Step 2) Based on the energy deposition data, the carrier generation and transport simulation was performed using the silicon microstrip detector simulation software WeightField2, and the detector induced current diagram was output. Step 3) Based on the detector's induced current diagram, use LTSpice software to simulate the preamplifier circuit and output the complete output waveform of the charged particle. Step 1) includes: Step 1-1) Use the high-energy physics simulation software Geant4 to set the geometric parameters of the detector and the relevant properties of the particle source; Steps 1-2) Select a physical model to describe the interaction between the particle and the detector; Steps 1-3) Perform irradiation simulation of the particle source and statistically analyze the energy deposition caused by different particles in the silicon detector; Steps 1-4) Obtain energy deposition data at different depths in micrometers, and output them in CSV format; The geometric parameters of the detector in step 1-1) include: a nanoscale aluminum metallization layer and a micrometer-scale silicon layer; the relevant properties of the particle source include: the type and energy of the particles to be simulated.

2. The full-process physical simulation method for a charged particle waveform acquisition system according to claim 1, characterized in that, The full-process physical simulation includes: ionization process, plasma erosion effect, carrier transport effect, detector induced charge and preamplifier voltage waveform.

3. The full-process physical simulation method for a charged particle waveform acquisition system according to claim 1, characterized in that, Step 2) includes: Step 2-1) Use the silicon microstrip detector simulation software WeightField2 to read the energy deposition data output by the high-energy physics simulation software Geant4, and calculate the number of electron-hole pairs generated at each location of the detector. Step 2-2) Combining carrier transport effect and plasma erosion effect, simulate the process of electron-hole pair movement in silicon detector; Steps 2-3) Calculate the magnitude and changes of the induced current on the two plates of the detector, and output the induced current diagram of the detector.

4. The full-process physical simulation method for a charged particle waveform acquisition system according to claim 1, characterized in that, Step 3) includes: Based on the detector's induced current diagram, and considering the resistive input impedance and high gain characteristics, a preamplifier circuit model was established using LTSpice software. By adjusting the circuit parameters, simulating and optimizing the preamplifier circuit model, and reducing the distortion introduced by the circuit, an optimized preamplifier circuit is obtained, which outputs a complete waveform of charged particles.

5. The full-process physical simulation method for a charged particle waveform acquisition system according to claim 4, characterized in that, The circuit parameters include gain and frequency response.

6. A platform based on the full-process physical simulation method for a charged particle waveform acquisition system as described in claim 1, characterized in that, The platform includes: The ionization process simulation module is used to perform particle simulation and energy deposition calculation using the high-energy physics simulation software Geant4, and outputs energy deposition data at different depths. The carrier generation and transport simulation module is used to simulate carrier generation and transport using the silicon microstrip detector simulation software WeightField2 based on energy deposition data, and outputs the detector induced current map; and The charged particle waveform output module is used to simulate the preamplifier circuit using LTSpice software based on the detector's induced current diagram, and output the complete waveform of the charged particle.

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