Simulation calculation and imaging method, device and equipment for proton blocking capability

Abstract

The invention relates to a simulation calculation and imaging method, device and equipment for a proton blocking capability, and belongs to the technical field of ionizing radiation calculation. The method comprises the following steps: partitioning incident proton energy, and obtaining a motion step length of a proton in a target substance based on the energy partitioning; in each motion step length, electron blocking capability calculation based on energy partition, nuclear blocking capability calculation based on a nuclear blocking section and compound blocking capability calculation based on a compound element are sequentially carried out, and the total blocking capability in each motion step length is comprehensively obtained, simplified into the same value and stored; and energy loss rate simulation calculation and imaging of the target material for different incident proton energies are realized. The method can effectively improve the precision and efficiency of proton energy loss rate calculation imaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ionizing radiation calculation, in particular to a simulation calculation and imaging method, device and equipment for proton stopping power. BACKGROUND

[0002] After the protons enter the target material, the energy is transferred to the atoms of the target material due to the Coulomb interaction, and the energy gradually decreases. This process can be regarded as the stopping of the protons by the target material, and the stopping power of the target material to the protons (also known as the energy loss rate) is defined as the energy loss per unit path. The precise data is an important basis for proton therapy, proton imaging and material analysis and other technologies.

[0003] At present, the data is mainly obtained by simulation calculation technology based on physical model. By establishing a physical model of the interaction between protons and matter, and using a computer to solve the numerical value, theoretical data support is provided for proton imaging and other applications. However, the existing simulation calculation method still has significant deficiencies, which limits the accuracy and efficiency of its practical application, which is specifically manifested in: First, the simulation results in a wide energy range are not consistent: the simulation accuracy of the existing calculation model is difficult to remain consistent when crossing a wide range of proton energy. Especially in the medium energy region, due to the imperfect description of the complex physical processes such as charge state exchange and electron environment effect, there is a large deviation between the calculation results and the experimental measurement values. Secondly, the calculation efficiency is low and the time-consuming is long: the calculation efficiency of the current simulation method is low. In order to obtain reliable results with statistical significance, a large number of particle trajectory operations are required, resulting in large consumption of computing resources and long time consumption, which seriously restricts the practicality in proton imaging and other applications that require rapid analysis of complex scenes.

[0004] In summary, the simulation calculation method for the stopping power of protons in the prior art has the problems of insufficient calculation accuracy in the whole energy region and low calculation efficiency, which affects the quantitative analysis accuracy of proton imaging. Therefore, it is a technical problem to be solved by those skilled in the art to seek a simulation calculation and imaging method for the stopping power of protons by the target material with high efficiency, high precision and stability. SUMMARY

[0005] Therefore, it is necessary to provide a simulation calculation and imaging method, device and equipment for the stopping power of protons in view of the above technical problems.

[0006] A simulation calculation and imaging method for the stopping power of protons, the method comprising: Step 1, obtaining the incident energy when the protons enter the target material, and dividing the proton energy range into different energy intervals to obtain the energy region where the incident energy is located; Step 2, the trajectory of the proton in the target substance is tracked by using a molecular dynamics algorithm, and the initial movement step of the proton is obtained according to the energy region where the incident energy is located. In the initial movement step, the electron stopping power is calculated according to the energy partition electron stopping power model, and then the nuclear stopping power is calculated according to the nuclear stopping cross section, and the compound stopping power is calculated according to the compound elements of the target substance; Step 3, the total stopping power of the target substance to the proton in the initial movement step is obtained by synthesizing the electron stopping power, the nuclear stopping power and the compound stopping power, and is simplified to the same value and stored. The energy loss of the proton in the initial movement step is obtained by multiplying the total stopping power by the initial movement step, and then the initial energy of the proton and the energy region where the initial energy is located are obtained. Step 4, according to the energy region where the initial energy of the proton is located, steps 2 and 3 are repeatedly executed to obtain the movement step of the proton each time, and the total stopping power of the target substance to the proton in each movement step is calculated and stored, until the energy of the proton is exhausted, the stopping power simulation calculation is stopped, and the energy loss rate imaging of the proton is realized based on the stored data.

[0007] In one of the embodiments, the proton energy range is divided into different energy intervals, including: The proton energy range is divided into different energy intervals according to the first threshold value and the second threshold value, the first threshold value is greater than the second threshold value; wherein the proton energy greater than or equal to the first threshold value is the high energy region, the proton energy between the first threshold value and the second threshold value is the medium energy region, and the proton energy less than or equal to the second threshold value is the low energy region.

[0008] In one of the embodiments, the method further comprises: in the target substance, the high energy region proton travels according to the first movement step, the medium energy region proton and the low energy region proton travel according to the second movement step; wherein the first movement step is 100 times of the second movement step, and it is assumed that the trajectory of the proton in the target substance is a straight line.

[0009] In one of the embodiments, the electron stopping power calculation according to the energy partition electron stopping power model includes: In the energy partition electron stopping power model, for the high energy region proton, the electron stopping power is calculated by using the Bethe theory formula, and the calculation expression is: ; Wherein, represents the proton energy The energy loss rate in the distance ; is the dielectric constant, is the proton charge number, is the atomic number of the target substance, The number of target material atoms per unit volume. The rest mass of the proton. For the velocity of the proton, The proton charge. At the speed of light, It is the average excitation and ionization energy of the target material atoms, and ; Electron volts are the unit of electron volts. For protons in the middle energy range, the electron stopping power is calculated using the Andersen-Ziegler theoretical formula. The calculation expression is as follows: ; in, Represents Avogadro's constant. The atomic mass number of the target material; The calculation expression is: ; ; ; in, Based on the overall compliance parameters of the experiment, Based on the low-energy coincidence parameters of the experiment, Based on the high-energy coincidence parameters of the experiment, , , All with , related, The value representing the ratio of the proton's kinetic energy to the proton's atomic mass (units); , , and It is a coefficient related to the target material, and the corresponding value is obtained from experiments; For protons in the low-energy region, the electron stopping power is calculated using empirical formulas for the low-energy region. The calculation expression is as follows: ; ; in, It is also a coefficient related to the target material. The cross-section is related to the target material and proton energy.

[0010] In one embodiment, nuclear stopping capability is calculated based on the nuclear stopping cross section, expressed as: ; ; ; ; in, The nuclear stopping cross section of the target material. To reduce the energy correlation coefficient, the subscript is... Indicates the number of atoms in the target material. To reduce energy, and These are the atomic numbers of the proton and the target material, respectively. and These represent the masses of the proton and the target material, respectively.

[0011] In one embodiment, the compound blocking ability is calculated based on the compound elements of the target material, expressed as: ; Among them, subscript Represents a compound, For the density of the compound, Indicates the first in the compound The weighting coefficient of the mass barrier ability of each element. Indicates the first in the compound The density of each element.

[0012] In one embodiment, proton energy loss rate imaging is performed based on stored data, including: A matrix is ​​created to store the total stopping power of the target material and the travel distance of the proton in each movement step. By inputting the matrix into visualization software, the incident energy and energy loss rate, travel distance and energy loss rate of the proton are plotted.

[0013] A simulation and imaging device for proton stopping ability, the device comprising: The energy partitioning module is used to obtain the incident energy when a proton enters the target material, and obtains the energy region where the incident energy is located by dividing the proton energy range into different energy intervals. The stopping power calculation module is used to track the trajectory of protons in the target material using molecular dynamics algorithms, and obtain the initial motion step size of the protons based on the energy region of the incident energy. Within the initial motion step size, the electronic stopping power is calculated first based on the electronic stopping power model of the energy region, and then the nuclear stopping power is calculated based on the nuclear stopping cross section and the compound stopping power is calculated based on the compound elements of the target material. The energy loss calculation module is used to integrate electron stopping power, nuclear stopping power and compound stopping power to obtain the total stopping power of the target material against the proton within the initial motion step and simplify it to the same value before storing it. By multiplying the total stopping power by the initial motion step, the energy loss of the proton within the initial motion step is obtained, and then the initial energy of the proton and its energy region for the next motion are obtained. The imaging module is used to repeatedly call the stopping power calculation module and the energy loss calculation module according to the energy region where the initial energy of the proton is located each time it travels, to obtain the motion step length of the proton for each motion step, and to calculate and store the total stopping power of the target material on the proton within each motion step length, until the proton energy is exhausted, at which point the stopping power simulation calculation stops, and the energy loss rate imaging of the proton is realized based on the stored data.

[0014] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps: Step 1: Obtain the incident energy when a proton enters the target material, and obtain the energy region where the incident energy is located by dividing the proton energy range into different energy intervals; Step 2: Use molecular dynamics algorithm to track the trajectory of protons in the target material, and obtain the initial motion step length of the protons based on the energy region of the incident energy. Within the initial motion step length, first calculate the electron stopping power based on the electron stopping power model of the energy region, then calculate the nuclear stopping power based on the nuclear stopping cross section and the compound stopping power based on the compound elements of the target material. Step 3: Combine the electron stopping power, nuclear stopping power and compound stopping power to obtain the total stopping power of the target material against the proton within the initial motion step length, simplify it to the same value and store it. By multiplying the total stopping power by the initial motion step length, the energy loss of the proton within the initial motion step length is obtained, and then the initial energy of the proton and its energy region for the next motion are obtained. Step 4: Based on the energy region of the initial energy of each proton's movement, repeat steps 2 and 3 to obtain the movement step length of each proton's movement and calculate and store the total stopping power of the target material against the proton within each movement step length until the proton's energy is exhausted. Stop the simulation calculation of stopping power and realize the proton's energy loss rate imaging based on the stored data.

[0015] The aforementioned method, apparatus, and device for simulating and imaging proton stopping power, by partitioning the incident proton energy and obtaining the proton's motion step size in the target material based on the energy partition, allows the step size setting to match the motion law of the proton at different energy stages, avoiding calculation deviations caused by fixed step sizes. Furthermore, by simplifying the total stopping power within a motion step size range to a single value for storage, it can reduce the amount of computation and the operation time, thereby improving computational efficiency. By performing electron stopping power calculation based on energy partitions within each motion step size, it can match an electron stopping power calculation model that is more in line with the actual physical process for each energy range, avoiding deviations caused by using a single model to cover the entire energy range, thus improving the accuracy of electron stopping power simulation calculation. By combining nuclear stopping power based on nuclear stopping cross section and compound stopping power based on compound elements to calculate the total stopping power, it can realize the simulation calculation and imaging of the energy loss rate of the target material for different incident proton energies, covering the key physical processes of proton-target material interaction, effectively improving the accuracy of stopping power simulation calculation and imaging. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a water body model in one embodiment; Figure 2 This is a flowchart illustrating the simulation calculation and imaging method for proton stopping power in one embodiment; Figure 3 This is a flowchart illustrating the process of preventing capability simulation calculations in one embodiment; Figure 4 This is a schematic diagram comparing the proton energy loss rate when the target material is H atoms in one embodiment. Figure 5 This is a schematic diagram comparing the proton energy loss rate when the target material is O atoms in one embodiment. Figure 6 This is a schematic diagram comparing the proton energy loss rate when the target material is water molecules in one embodiment. Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0018] In one embodiment, a method for simulating and imaging proton stopping power is provided, which is then applied to applications such as... Figure 1The following example illustrates the calculation of proton energy loss in a target material using a water model. The water model is designed as an infinitely large homogeneous medium with a water density of 1 g / cm³. Protons of different energies are injected perpendicularly into the water model. To simplify the calculation, the water model is subject to the following constraints: the trajectory of the proton is approximated as a straight line; the binding of protons with electrons in the target material is not considered; quantum effects are ignored; and the outer electrons of the target material are considered stationary.

[0019] It is important to note that the above constraints are only for simplifying the computational design. In practical applications, Coulomb scattering between protons and the target material's atomic nuclei can also be considered. By studying Coulomb scattering, the trajectory of protons within the target material can be simulated, transforming the two-dimensional trajectory into a three-dimensional motion. This allows for a more accurate determination of the Bragg peak position of the proton within the target material, providing a more precise reference for simulating proton energy loss rate. Secondly, the scenario of protons picking up electrons within the target material can also be considered. Studying the energy deposition of neutral particles after electron pickup can significantly improve the accuracy of energy deposition calculations within the target material. Furthermore, other interaction mechanisms between protons and the target material can be incorporated into the research to further enhance the accuracy of the simulation calculations.

[0020] Before stopping the ability simulation calculation, the following parameter settings are required, including: (1) Initial conditions: Constant: Proton mass m p =1.673e-27 kg Electron mass m e =9.109e-31 kg Avogadro's constant =6.022e23 mol -1 speed of light c =3e8 m / s charge q =1.6e-19 C dielectric constant =8.85e-12; Average ionization energy of H atom I1 = 3.04e-18 J The average ionization energy of the O atom is I² = 1.68e⁻¹⁷ J H atomic material coefficient A 11 =1.262、A 12 =1.44、A 13 =242.6、A 14 =1.2e4、A 15 =0.1159, O atomic material coefficient A 21 =2.652、A 22 =3、A 23 =1920, A24 =2000、A 25 =0.0223, the first step size of the proton in the high-energy region is bu=1e-7 m The second step size of protons in the medium-energy region and the low-energy region is bu = 1e-9 m .

[0021] Variable: Proton energy Energy0 ( J ), always preventing the ability eion ( J / m ), electronic blocking ability eion1 ( J / m ), nuclear deterrence ability eion2 ( J / m ), compound inhibits the ability of eion3 ( J / m ), the distance d that the proton travels in the target material cm ).

[0022] (2) Initial state: Protons are injected into the target material with different energies. The atoms in the target material are evenly distributed. Each time the proton moves one movement step, the energy loss rate of the proton is calculated based on the initial energy of the proton when it enters each movement step. Matrices Se and d are created to store the energy loss rate of the proton and the distance traveled by the proton each time.

[0023] (3) Boundary conditions: The algorithm stops running when the energy of the protons is exhausted.

[0024] After the above settings, as Figure 2 and Figure 3 As shown, the method proposed in this application includes the following steps: Step 1: Obtain the incident energy when a proton enters the target material, and obtain the energy region where the incident energy is located by dividing the proton energy range into different energy intervals.

[0025] Step 2: Molecular dynamics algorithm is used to track the trajectory of protons in the target material. Based on the energy region of the incident energy, the initial motion step length of the proton is obtained. Within the initial motion step length, the electron stopping power is calculated first based on the electron stopping power model of the energy region, and then the nuclear stopping power is calculated based on the nuclear stopping cross section and the compound stopping power is calculated based on the compound elements of the target material.

[0026] Step 3: Combine the electron stopping power, nuclear stopping power and compound stopping power to obtain the total stopping power of the target material against the proton within the initial motion step length. After simplifying it to the same value, store it. By multiplying the total stopping power by the initial motion step length, obtain the energy loss of the proton within the initial motion step length, and then obtain the initial energy of the proton's next movement and its energy range.

[0027] Step 4: Based on the energy region of the initial energy of each proton's movement, repeat steps 2 and 3 to obtain the movement step length of each proton's movement and calculate and store the total stopping power of the target material against the proton within each movement step length until the proton's energy is exhausted. Stop the simulation calculation of stopping power and realize the proton's energy loss rate imaging based on the stored data.

[0028] In the aforementioned simulation and imaging method for proton stopping power, the incident proton energy is partitioned, and the proton's motion step size in the target material is obtained based on the energy partition. This allows the step size setting to match the motion law of the proton at different energy stages, avoiding calculation deviations caused by fixed step sizes. Furthermore, by simplifying the total stopping power within a motion step size range to a single value for storage, the computational load and time can be reduced, improving computational efficiency. By performing electron stopping power calculation based on energy partitions within each motion step size, an electron stopping power calculation model that more closely matches the actual physical process can be matched for each energy range, avoiding deviations caused by using a single model to cover the entire energy range, thus improving the accuracy of electron stopping power simulation. By combining nuclear stopping power based on nuclear stopping cross-sections and compound stopping power based on compound elements to calculate the total stopping power, the energy loss rate of the target material for different incident proton energies can be simulated and imaged, covering the key physical processes of proton-target material interaction, effectively improving the accuracy of stopping power simulation and imaging.

[0029] Furthermore, the proton energy range is divided into different energy intervals, including: dividing the proton energy range into different energy intervals according to a preset first threshold and a second threshold, where the first threshold is greater than the second threshold; wherein, a proton energy greater than or equal to the first threshold is the high-energy region, a proton energy between the first and second thresholds is the medium-energy region, and a proton energy less than or equal to the second threshold is the low-energy region. Specifically, the first threshold is set to 0.6 MeV, and the second threshold is set to 10 keV.

[0030] Furthermore, the method also includes: in the target material, high-energy protons move according to a first motion step size, while medium-energy and low-energy protons move according to a second motion step size; wherein the first motion step size is 100 times the second motion step size, and it is assumed that the trajectory of the protons in the target material is a straight line. It should be understood that setting the proton motion step size based on energy partitions can avoid the calculation deviation caused by a fixed step size, and for medium-energy and low-energy protons, the error caused by discretization of the motion step size at a lower order of magnitude is smaller when simulating a continuous process, and the simulation results will theoretically be closer to the real physical situation.

[0031] Furthermore, the electron blocking power is calculated based on the electron blocking power model of the energy partition, including: In the electron stopping power model for energy partitioning, the electron stopping power for high-energy protons is calculated using Bethe's theory. Bethe's theory, derived from the theory of inelastic collisions between protons and extranuclear electrons, reflects the functional relationship between the ionization energy loss rate and the proton velocity and target material parameters. The calculation expression is as follows: ; in, Represents proton energy Distance traveled Energy loss rate within; Where is the dielectric constant. The number of proton charges. The atomic number of the target material. The number of target material atoms per unit volume. The rest mass of the proton. For the velocity of the proton, The proton charge. At the speed of light, It is the average excitation and ionization energy of the target material atoms, and ; It is the unit of electron volts.

[0032] For protons in the middle energy range, the electron stopping power is calculated using the Andersen-Ziegler theoretical formula. The calculation expression is as follows: ; in, Represents Avogadro's constant. The atomic mass number of the target material; The calculation expression is: ; ; ; in, Based on the overall compliance parameters of the experiment, Based on the low-energy coincidence parameters of the experiment, Based on the high-energy coincidence parameters of the experiment, , , All with , related; This represents the ratio of the proton's kinetic energy to the atomic mass of the proton (approximately 1.0073). , , and These are coefficients related to the target material, with corresponding values ​​obtained experimentally. For example, for the elements C, H, O, and N in human tissue, their coefficients... , , and As shown in Table 1.

[0033] Table 1. Material coefficients of target materials in the medium energy region.

[0034] For protons in the low-energy region, the electron stopping power is calculated using empirical formulas for the low-energy region. The calculation expression is as follows: ; ; in, It is also a coefficient related to the target material. The cross-section is related to the target material and proton energy. The unit is eV / ((10 15 atoms) / cm 2 For the elements C, H, O, and N in human tissues, their coefficients... As shown in Table 2.

[0035] Table 2 Target material coefficients in the low-energy region

[0036] When a proton interacts with the target material, it primarily loses energy through inelastic scattering with its outer electrons. When the proton energy is very low (≈0.01 MeV), the target material exhibits a significant nuclear stopping power against the proton. Therefore, when the proton energy is very low, the energy loss from elastic collisions with the target nucleus becomes negligible. Furthermore, the nuclear stopping power is calculated based on the nuclear stopping cross-section, and the expression is: ; ; ; ; in, Nuclear stopping cross section of the target material (unit: eV / (atom / cm)) 2 )), To reduce the energy correlation coefficient, the subscript is... Indicates the number of atoms in the target material. To reduce energy, and These are the atomic numbers of the proton and the target material, respectively. and These are the masses of the proton and the target material, respectively (in amu).

[0037] Furthermore, the compound blocking ability is calculated based on the compound elements of the target substance, and the expression is: ; Among them, subscript Represents a compound, For the density of the compound, Indicates the first in the compound The weighting coefficient of the mass barrier ability of each element. Indicates the first in the compound The density of each element.

[0038] Furthermore, proton energy loss rate imaging is achieved based on stored data, including: A matrix is ​​created to store the total stopping power of the target material and the travel distance of the proton in each movement step. By inputting the matrix into visualization software, the incident energy and energy loss rate, travel distance and energy loss rate of the proton are plotted.

[0039] Specifically, the blocking ability simulation calculation in the program of the method proposed in this application (hereinafter referred to as "this program") is implemented using MATLAB, and the image rendering is implemented using LabVIEW software. To verify the effectiveness of this program, the proton energy loss rate calculation results of this program were further compared with the data from the National Institute of Standards and Technology (NIST). The proton energy loss rates when the target material is H atoms, O atoms, and water molecules were compared respectively. During the comparison process, the density of the target material was set to 1 g / cm³. 3 The energy range of the proton is 0-10 MeV, and the results are as follows: Figures 4 to 6 As shown.

[0040] like Figures 4 to 6 As shown, the energy loss of protons in the target material peaks near 0.1 MeV, forming a relatively sharp peak (i.e., the Bragg peak). After the Bragg peak, the proton energy loss rate decreases rapidly. For the H atom, the maximum proton energy loss rate is approximately 3800 MeV / cm, while for the O atom, which has a higher atomic number than H, the maximum proton energy loss rate is only about 650 MeV / cm. For the compound H₂O, the maximum proton energy loss rate falls between the two single-element values, at approximately 1000 MeV / cm. These three figures demonstrate that the results calculated by this program show good agreement with NIST data when calculating the proton energy loss rate in the target material.

[0041] In one embodiment, a simulation and imaging apparatus for proton stopping ability is provided, comprising: The energy partitioning module is used to obtain the incident energy when a proton enters the target material, and obtains the energy region where the incident energy is located by dividing the proton energy range into different energy intervals. The stopping power calculation module is used to track the trajectory of protons in the target material using molecular dynamics algorithms, and obtain the initial motion step size of the protons based on the energy region of the incident energy. Within the initial motion step size, the electronic stopping power is calculated first based on the electronic stopping power model of the energy region, and then the nuclear stopping power is calculated based on the nuclear stopping cross section and the compound stopping power is calculated based on the compound elements of the target material. The energy loss calculation module is used to integrate electron stopping power, nuclear stopping power and compound stopping power to obtain the total stopping power of the target material against the proton within the initial motion step and simplify it to the same value before storing it. By multiplying the total stopping power by the initial motion step, the energy loss of the proton within the initial motion step is obtained, and then the initial energy of the proton and its energy region for the next motion are obtained. The imaging module is used to repeatedly call the stopping power calculation module and the energy loss calculation module according to the energy region where the initial energy of the proton is located each time it travels, to obtain the motion step length of the proton for each motion step, and to calculate and store the total stopping power of the target material on the proton within each motion step length, until the proton energy is exhausted, at which point the stopping power simulation calculation stops, and the energy loss rate imaging of the proton is realized based on the stored data.

[0042] Specific limitations regarding the simulation and imaging apparatus for proton stopping power can be found in the limitations of the simulation and imaging method for proton stopping power described above, and will not be repeated here. Each module in the aforementioned simulation and imaging apparatus for proton stopping power can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the operations corresponding to each module.

[0043] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When executed by the processor, the computer program implements a simulation calculation and imaging method for proton stopping ability. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0044] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0045] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to perform the following steps: Step 1: Obtain the incident energy when a proton enters the target material, and obtain the energy region where the incident energy is located by dividing the proton energy range into different energy intervals; Step 2: Use molecular dynamics algorithm to track the trajectory of protons in the target material, and obtain the initial motion step length of the protons based on the energy region of the incident energy. Within the initial motion step length, first calculate the electron stopping power based on the electron stopping power model of the energy region, then calculate the nuclear stopping power based on the nuclear stopping cross section and the compound stopping power based on the compound elements of the target material. Step 3: Combine the electron stopping power, nuclear stopping power and compound stopping power to obtain the total stopping power of the target material against the proton within the initial motion step length, simplify it to the same value and store it. By multiplying the total stopping power by the initial motion step length, the energy loss of the proton within the initial motion step length is obtained, and then the initial energy of the proton and its energy region for the next motion are obtained. Step 4: Based on the energy region of the initial energy of each proton's movement, repeat steps 2 and 3 to obtain the movement step length of each proton's movement and calculate and store the total stopping power of the target material against the proton within each movement step length until the proton's energy is exhausted. Stop the simulation calculation of stopping power and realize the proton's energy loss rate imaging based on the stored data.

[0046] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A simulation calculation and imaging method for proton stopping power, characterized in that, The method includes: Step 1: Obtain the incident energy when a proton enters the target material, and obtain the energy region where the incident energy is located by dividing the proton energy range into different energy intervals; Step 2: Use molecular dynamics algorithm to track the trajectory of protons in the target material, and obtain the initial motion step length of the protons based on the energy region of the incident energy. Within the initial motion step length, first calculate the electron stopping power based on the electron stopping power model of the energy region, then calculate the nuclear stopping power based on the nuclear stopping cross section and the compound stopping power based on the compound elements of the target material. Step 3: Combine the electron stopping power, nuclear stopping power and compound stopping power to obtain the total stopping power of the target material against the proton within the initial motion step length, simplify it to the same value and store it. By multiplying the total stopping power by the initial motion step length, the energy loss of the proton within the initial motion step length is obtained, and then the initial energy of the proton and its energy range for the next movement are obtained. Step 4: Based on the energy region of the initial energy of each proton's movement, repeat steps 2 and 3 to obtain the movement step length of each proton's movement and calculate and store the total stopping power of the target material against the proton within each movement step length until the proton's energy is exhausted. Stop the simulation calculation of stopping power and realize the proton's energy loss rate imaging based on the stored data.

2. The simulation calculation and imaging method for proton stopping power according to claim 1, characterized in that, The proton energy range is divided into different energy intervals, including: The proton energy range is divided into different energy intervals based on a preset first threshold and a second threshold, wherein the first threshold is greater than the second threshold; wherein, the proton energy greater than or equal to the first threshold is the high-energy region, the proton energy between the first threshold and the second threshold is the medium-energy region, and the proton energy less than or equal to the second threshold is the low-energy region.

3. The simulation calculation and imaging method for proton stopping power according to claim 2, characterized in that, The method further includes: in the target material, high-energy protons move according to a first motion step size, and medium-energy protons and low-energy protons move according to a second motion step size; wherein, the first motion step size is 100 times the second motion step size, and it is assumed that the trajectory of the proton in the target material is a straight line.

4. The simulation calculation and imaging method for proton stopping power according to claim 3, characterized in that, Electron stopping power is calculated based on the electron stopping power model of the energy partition, including: In the electron stopping power model for the energy partition, for the high-energy proton, the electron stopping power is calculated using Bethe's theory formula, and the calculation expression is as follows: ； in, Represents proton energy Distance traveled Energy loss rate within; Where is the dielectric constant. The number of proton charges. The atomic number of the target material. The number of target material atoms per unit volume. The rest mass of the proton. For the velocity of the proton, The proton charge. At the speed of light, It is the average excitation and ionization energy of the target material atoms, and ; Electron volts are the unit of electron volts. For protons in the middle energy range, the electron stopping power is calculated using the Andersen-Ziegler theoretical formula. The calculation expression is as follows: ； in, Represents Avogadro's constant. The atomic mass number of the target material; The calculation expression is: ； ； ； in, Based on the overall compliance parameters of the experiment, Based on the low-energy coincidence parameters of the experiment, Based on the high-energy coincidence parameters of the experiment, , , All with , related, The value representing the ratio of the proton's kinetic energy to the proton's atomic mass (units); , , and It is a coefficient related to the target material, and the corresponding value is obtained from experiments; For protons in the low-energy region, the electron stopping power is calculated using empirical formulas for the low-energy region. The calculation expression is as follows: ； ； in, It is also a coefficient related to the target material; The cross-section is related to the target material and proton energy.

5. The simulation calculation and imaging method for proton stopping power according to claim 4, characterized in that, The nuclear stopping capability is calculated based on the nuclear stopping cross section, and the expression is: ； ； ； ； in, The nuclear stopping cross section of the target material. To reduce the energy correlation coefficient, the subscript is... Indicates the number of atoms in the target material. To reduce energy, and These are the atomic numbers of the proton and the target material, respectively. and These represent the masses of the proton and the target material, respectively.

6. The simulation calculation and imaging method for proton stopping power according to claim 4, characterized in that, The compound blocking ability is calculated based on the elemental composition of the target substance, and the expression is as follows: ； Among them, subscript Represents a compound, For the density of the compound, Indicates the first in the compound The weighting coefficient of the mass barrier ability of each element. Indicates the first in the compound The density of each element.

7. The simulation calculation and imaging method for proton stopping power according to claim 1, characterized in that, Imaging of proton energy loss rate based on stored data includes: A matrix is ​​created to store the total stopping power of the target material and the travel distance of the proton in each movement step. The matrix is ​​then input into visualization software to generate images of the incident energy and energy loss rate, travel distance and energy loss rate of the proton.

8. A simulation and imaging device for proton stopping ability, characterized in that, The device includes: The energy partitioning module is used to obtain the incident energy when a proton enters the target material, and obtains the energy region where the incident energy is located by dividing the proton energy range into different energy intervals. The stopping power calculation module is used to track the trajectory of protons in the target material using molecular dynamics algorithms, and obtain the initial motion step size of the protons based on the energy region where the incident energy is located. Within the initial motion step size, the electronic stopping power is first calculated based on the electronic stopping power model of the energy region, and then the nuclear stopping power is calculated based on the nuclear stopping cross section and the compound stopping power is calculated based on the compound elements of the target material. The energy loss calculation module is used to integrate the electron stopping power, nuclear stopping power and compound stopping power to obtain the total stopping power of the target material against the proton within the initial motion step and simplify it to the same value before storing it. By multiplying the total stopping power by the initial motion step, the energy loss of the proton within the initial motion step is obtained, and then the initial energy of the proton and its energy region for the next movement are obtained. The imaging module is used to repeatedly call the stopping power calculation module and the energy loss calculation module according to the energy region where the initial energy of the proton is located each time it travels, to obtain the motion step length of the proton for each motion step, and to calculate and store the total stopping power of the target material on the proton within each motion step length, until the proton energy is exhausted, at which point the stopping power simulation calculation stops, and the energy loss rate imaging of the proton is realized based on the stored data.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

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