A method for determining the secondary electron emission coefficient of a random dot matrix

Abstract

The present invention discloses a method for determining the secondary electron emission coefficient of a random dot matrix, including: establishing a three-dimensional position model of the dot matrix spatial structure; determining a standard incident electron set; calculating the number of secondary electrons generated when N incident electrons with an initial incident energy of E 0 , an initial incident angle of θ 0 are incident on the three-dimensional position model of the dot matrix spatial structure; calculating the secondary electron emission coefficient of the three-dimensional position model of the dot matrix spatial structure at an initial incident energy of E 0 , an initial incident angle of θ 0 ; obtaining the experimental value of the secondary electron emission coefficient obtained through experiments and determining a correction coefficient; changing the initial incident energy and the initial incident angle of the incident electrons, calculating the secondary electron emission coefficients of the three-dimensional position model of the dot matrix spatial structure at different initial incident energies E k , different initial incident angles θ k , and outputting the results after correction. The present invention realizes the determination of the secondary electron emission coefficient of a 3D printed random dot matrix, and has the advantages of stable physical structure and excellent combination with devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of space material surface science, and particularly relates to a method for determining the secondary electron emission coefficient of a random lattice. Background Technique

[0002] Electron avalanche breakdown, microdischarge, low-pressure discharge, etc. caused by secondary electron emission are common technical bottlenecks that affect the safe, reliable, and long-term in-orbit operation of high-power microwave systems on spacecraft. When they occur, they often cause system signal interruption, power reduction, surface damage of devices, and even catastrophic hard failures that cannot be repaired in orbit, resulting in the in-orbit failure of satellites. Reducing the secondary electron emission coefficient (Secondary Electron Yield, SEY) of space microwave materials is an effective means to achieve anti-microdischarge design and increase the microdischarge power threshold.

[0003] Currently, the methods that can achieve the suppression of secondary electron emission of materials mainly include selecting new materials with low secondary electron emission coefficients, surface treatment of materials, etc. For high-power microwave components with special structures and complex configurations, on the premise of fully considering factors such as structural configuration and environmental aging, and combining the needs of structure and performance, a new method and new approach is to further complicate the cavity structure to reduce the secondary electron emission coefficient and improve the microdischarge performance. Summary of the Invention

[0004] The technical problem to be solved by the present invention: Overcoming the deficiencies of the prior art, providing a method for determining the secondary electron emission coefficient of a random lattice, constructing a three-dimensional position model of the 3D printed random lattice space structure through three-dimensional position points, combining with the secondary electron emission model, and considering the scattering characteristics of three-dimensional metal wires on electrons, to realize the determination of the secondary electron emission coefficient of the 3D printed random lattice, which has the advantages of stable physical structure and excellent combination with devices, and has great engineering application value and market prospects.

[0005] To solve the above technical problem, the present invention discloses a method for determining the secondary electron emission coefficient of a random lattice, including:

[0006] Step 1, establishing a three-dimensional position model of the lattice space structure;

[0007] Step 2, determining a standard incident electron set; wherein, the standard incident electron set includes N incident electrons, and the initial incident energy of each incident electron in the standard incident electron set is E 0 , the initial incident angle is θ 0 , and the initial incident positions are respectively E 0 = 100 eV, θ 0 = 0°, i = 1, 2, 3,..., N;

[0008] Step 3, calculate to obtain the initial incident energy as E 0 and the initial incident angle as θ 0 of the number N0 of secondary electrons generated when N incident electrons are incident on the three-dimensional position model of the lattice space structure;

[0009] Step 4, according to N0, calculate to obtain the secondary electron emission coefficient De10 of the three-dimensional position model of the lattice space structure at the initial incident energy of E 0 and the initial incident angle of θ 0 ;

[0010] Step 5, obtain the experimental value Der of the secondary electron emission coefficient obtained experimentally, and determine the correction coefficient AW according to Der and De10;

[0011] Step 6, change the initial incident energy and the initial incident angle of the incident electrons to obtain K sets of incident electron sets with different initial incident energies and different initial incident angles; wherein, the initial incident energy of each incident electron in the k-th set of incident electron sets is E k and the initial incident angle is θ k and the initial incident positions are respectively k = 1, 2, 3,..., K, j = 1, 2, 3,..., M k , M k represents the number of incident electrons in the k-th set of incident electron sets; repeat Steps 3 to 4, and calculate to obtain the secondary electron emission coefficient De1 of the three-dimensional position model of the lattice space structure at different initial incident energies E k and different initial incident angles θ k ; k ;

[0012] Step 7, correct De1 k according to the correction coefficient AW to obtain the corrected secondary electron emission coefficient De of the three-dimensional position model of the lattice space structure at different initial incident energies E k and different initial incident angles θ k and output it. k ;

[0013] In the above method for determining the secondary electron emission coefficient of the random lattice, establishing the three-dimensional position model of the lattice space structure includes:

[0014] Determine the actual physical structure of the 3D-printed random lattice;

[0015] Establish a random lattice space structure model corresponding to the actual physical structure of the random lattice;

[0016] Determine the position of the random dot array spatial structure indicated by the random dot array spatial structure model in the coordinate system O-XYZ, and sample the random dot array spatial structure at a set step size Δd;

[0017] According to the determined position of the random dot array spatial structure in the coordinate system O-XYZ, construct a three-dimensional position model of the dot array spatial structure; and according to the sampling result of the random dot array spatial structure, mark the attribute of each three-dimensional position in the three-dimensional position model of the dot array spatial structure as vacuum or material; when determining that the attribute of the three-dimensional position is material, mark the secondary electron emission characteristics of the material; among them, the secondary electron emission characteristics of the material include: the secondary electron emission model of the material and the model parameters.

[0018] In the above method for determining the secondary electron emission coefficient of the random dot array, the coordinate system O-XYZ is a Cartesian coordinate system: the bottom of the outer shell of the actual physical structure of the random dot array is the XOY plane, and the upward extension direction of the actual physical structure of the random dot array is the Z axis.

[0019] In the above method for determining the secondary electron emission coefficient of the random dot array, 1nm ≤ Δd ≤ 1μm.

[0020] In the above method for determining the secondary electron emission coefficient of the random dot array, calculate that the initial incident energy is E 0 and the initial incident angle is θ 0 When N incident electrons are incident on the three-dimensional position model of the dot array spatial structure, the number N0 of secondary electrons generated includes:

[0021] Sub-step 31, according to the initial incident position and the initial incident angle θ 0 of the i-th incident electron, determine the straight-line motion trajectory A0 of the i-th incident electron, and determine the intersection point A of the straight-line motion trajectory A0 and the three-dimensional position model of the dot array spatial structure;

[0022] Sub-step 32, according to the incident energy and incident angle when the i-th incident electron collides with the intersection point A, combined with the secondary electron emission characteristics of the material at the intersection point A, calculate the number N si of secondary electrons generated by the collision;

[0023] Sub-step 33, according to the emission position and emission angle of the m-th secondary electron, determine whether the m-th secondary electron exits from the three-dimensional position model of the dot array spatial structure; where, 1 ≤ m ≤ N si ;

[0024] Sub-step 34, if it is determined that the m-th secondary electron exits from the three-dimensional position model of the dot array spatial structure, then the count of the number of generated secondary electrons is incremented by 1;

[0025] Sub-step 35: If it is determined that the m-th secondary electron does not exit from the three-dimensional position model of the lattice space structure, determine the linear motion trajectory B0 of the m-th secondary electron, and determine the intersection point B between the linear motion trajectory B0 and the three-dimensional position model of the lattice space structure; calculate the number of secondary electrons generated by the collision of the m-th secondary electron according to sub-step 32.

[0026] Sub-step 36: Iterate sub-steps 31 to 35 until the entire motion process of all secondary electrons generated by the collision of N incident electrons with an initial incident energy of E 0 and an initial incident angle of θ 0 is completed, and determine the number N0 of secondary electrons generated when N incident electrons with an initial incident energy of E 0 and an initial incident angle of θ 0 are incident on the three-dimensional position model of the lattice space structure.

[0027] In the above method for determining the secondary electron emission coefficient of a random lattice, the incident energy of the i-th incident electron when colliding with the intersection point A is the initial incident energy E 0 of the i-th incident electron; the incident angle of the i-th incident electron when colliding with the intersection point A is the angle between the linear motion trajectory A0 and the normal of the tangent plane of the random lattice space structure model at the intersection point A.

[0028] In the above method for determining the secondary electron emission coefficient of a random lattice, determining whether the m-th secondary electron exits from the three-dimensional position model of the lattice space structure according to the exit position and exit angle of the m-th secondary electron includes:

[0029] Determine the linear motion trajectory B0 of the m-th secondary electron according to the initial incident position and initial incident angle of the m-th secondary electron;

[0030] Judge whether there is an intersection point between the linear motion trajectory B0 and the three-dimensional position model of the lattice space structure;

[0031] If it is determined that there is an intersection point between the linear motion trajectory B0 and the three-dimensional position model of the lattice space structure, it is determined that the m-th secondary electron does not exit from the three-dimensional position model of the lattice space structure; otherwise, it is determined that the m-th secondary electron exits from the three-dimensional position model of the lattice space structure.

[0032] In the above method for determining the secondary electron emission coefficient of a random lattice, De10 = N0 / N.

[0033] In the above method for determining the secondary electron emission coefficient of a random lattice, AW = Der / De10.

[0034] In the above method for determining the secondary electron emission coefficient of a random lattice, De k = AW · De1 k .

[0035] The present invention has the following advantages:

[0036] (1) The present invention discloses a method for determining the secondary electron emission coefficient of a random lattice. By constructing a three-dimensional position model of the 3D-printed random lattice spatial structure from three-dimensional position points, combining with the secondary electron emission model, and considering the scattering characteristics of three-dimensional metal wires on electrons, the determination of the secondary electron emission coefficient of the 3D-printed random lattice is realized, which has the advantages of stable physical structure and excellent combination with devices, and has great engineering application value and market prospect.

[0037] (2) The present invention discloses a method for determining the secondary electron emission coefficient of a random lattice, which changes the limitation of the existing technology that can only determine the secondary electron emission coefficient of regular, simple, and periodic structures, is applicable to the determination of the secondary electron emission coefficient of any random lattice under specific conditions, and has passed experimental verification, with stronger applicability and broader application prospects. Description of the Drawings

[0038] Figure 1 is a flowchart of the steps of a method for determining the secondary electron emission coefficient of a random lattice in an embodiment of the present invention;

[0039] Figure 2 is a schematic diagram of a 3D-printed random lattice spatial structure in an embodiment of the present invention;

[0040] Figure 3 is a schematic diagram of the comparison between the result obtained by the method for determining the secondary electron emission coefficient of a random lattice according to the embodiment of the present invention and the measurement result in an embodiment of the present invention. Detailed Embodiments

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the disclosed embodiments of the present invention will be further described in detail below with reference to the drawings.

[0042] As Figure 1 , in this embodiment, the method for determining the secondary electron emission coefficient of a random lattice includes:

[0043] Step 1, establish a three-dimensional position model of the lattice spatial structure.

[0044] In this embodiment, first, the actual physical structure of the 3D-printed random lattice can be determined; then, a random lattice spatial structure model corresponding to the actual physical structure of the random lattice is established, such as Figure 2As shown; further, determine the position of the random dot matrix spatial structure indicated by the random dot matrix spatial structure model in the coordinate system O-XYZ, and sample the random dot matrix spatial structure at a set step size Δd; finally, construct a three-dimensional position model of the dot matrix spatial structure according to the determined position of the random dot matrix spatial structure in the coordinate system O-XYZ; and according to the sampling result of the random dot matrix spatial structure, mark the attribute of each three-dimensional position in the three-dimensional position model of the dot matrix spatial structure as vacuum or material; when determining that the attribute of the three-dimensional position is material, mark the secondary electron emission characteristics of the material; wherein, the secondary electron emission characteristics of the material include: the secondary electron emission model of the material and the model parameters.

[0045] It should be noted that the coordinate system O-XYZ is a Cartesian coordinate system: the bottom of the outer shell of the actual physical structure of the random dot matrix is the XOY plane, and the upward extension direction of the actual physical structure of the random dot matrix is the Z axis. 1nm ≤ Δd ≤ 1μm.

[0046] Step 2, determine the standard incident electron set.

[0047] In this embodiment, the standard incident electron set includes N incident electrons, and the initial incident energy of each incident electron in the standard incident electron set is E 0 , the initial incident angle is θ 0 , and the initial incident positions are respectively E 0 = 100eV, θ 0 = 0°, i = 1, 2, 3,..., N. That is, the initial incident energy of each incident electron in the standard incident electron set is 100eV, the initial incident angle is 0°, and the initial incident positions can be the same or different.

[0048] Step 3, calculate the number N0 of secondary electrons generated when N incident electrons with an initial incident energy of E 0 and an initial incident angle of θ 0 are incident on the three-dimensional position model of the dot matrix spatial structure.

[0049] In this embodiment, the calculation process of N0 is as follows:

[0050] Sub-step 31, according to the initial incident position of the i-th incident electron and the initial incident angle θ 0 , determine the linear motion trajectory A0 of the i-th incident electron, and determine the intersection point A of the linear motion trajectory A0 and the three-dimensional position model of the dot matrix spatial structure.

[0051] Sub-step 32, according to the incident energy and incident angle of the i-th incident electron when colliding with the intersection point A, combined with the secondary electron emission characteristics of the material at the intersection point A, calculate the number N of secondary electrons generated by the collisionsi Specifically, the incident energy and incident angle of the i-th incident electron can be used as inputs, substituted into the secondary electron emission model of the material at intersection point A, and combined with the model parameters to obtain the number N of secondary electrons generated by the collision at intersection point A. si Among them, the incident energy when the i-th incident electron collides with intersection point A is the initial incident energy E of the i-th incident electron. 0 The incident angle when the i-th incident electron collides with intersection point A is the angle between the linear motion trajectory A0 and the normal of the tangent plane of the random lattice space structure model at intersection point A.

[0052] Sub-step 33: Determine whether the m-th secondary electron exits from the three-dimensional position model of the lattice space structure according to the exit position and exit angle of the m-th secondary electron. Specifically, the linear motion trajectory B0 of the m-th secondary electron can be determined according to the initial incident position and initial incident angle of the m-th secondary electron; determine whether there is an intersection between the linear motion trajectory B0 and the three-dimensional position model of the lattice space structure; if it is determined that there is an intersection between the linear motion trajectory B0 and the three-dimensional position model of the lattice space structure, it is determined that the m-th secondary electron does not exit from the three-dimensional position model of the lattice space structure; otherwise, it is determined that the m-th secondary electron exits from the three-dimensional position model of the lattice space structure. Among them, 1 ≤ m ≤ N. si 。

[0053] It should be noted that if the exit energy of each secondary electron is denoted as E si , the exit angle as θ si , and the exit position as D si , then there is: E si is a random number generated between 0 and 5 eV. Defining the local coordinate system at the exit position D si can be used to determine the exit angle θ si : The local coordinate system 0'-X'Y'Z' at the exit position D si : The tangent plane of the three-dimensional position model of the lattice space structure at the exit position D si is the X'O'Y' plane of the local coordinate system, the intersection line of the X'O'Y' plane and the YOZ plane in the coordinate system O-XYZ is the X' axis in the X'O'Y' plane of the local coordinate system, and the normal direction of the tangent plane of the three-dimensional position model of the lattice space structure at the exit position D si is the Z' axis; then, the exit angle θ si and the angle components with the X', Y', and Z' axes of the local coordinate system are all random numbers between 0 and 90 degrees generated following a cosine distribution. The exit position D si is the position when the i-th incident electron collides with intersection point A.

[0054] Sub-step 34, if it is determined that the m-th secondary electron exits from the three-dimensional position model of the lattice space structure, the count of the number of generated secondary electrons is incremented by 1.

[0055] Sub-step 35, if it is determined that the m-th secondary electron does not exit from the three-dimensional position model of the lattice space structure, determine the straight-line motion trajectory B0 of the m-th secondary electron, and determine the intersection point B of the straight-line motion trajectory B0 and the three-dimensional position model of the lattice space structure; calculate the number of secondary electrons generated by the collision of the m-th secondary electron according to sub-step 32.

[0056] Sub-step 36, iterate sub-steps 31 to 35 until the entire motion process of all secondary electrons generated by the collision of N incident electrons with an initial incident energy of E 0 and an initial incident angle of θ 0 is completed, and determine the number N0 of secondary electrons generated when N incident electrons with an initial incident energy of E 0 and an initial incident angle of θ 0 are incident on the three-dimensional position model of the lattice space structure.

[0057] Step 4, according to N0, calculate the secondary electron emission coefficient De10 of the three-dimensional position model of the lattice space structure at an initial incident energy of E 0 and an initial incident angle of θ 0 : De10 = N0 / N.

[0058] Step 5, obtain the experimental value Der of the secondary electron emission coefficient, and determine the correction coefficient AW according to Der and De10.

[0059] In this embodiment, according to the actual physical structure and size of the 3D-printed random lattice, the experimental value Der of the secondary electron emission coefficient at an incident energy of 100 eV and an incident angle of 0 degrees can be obtained through experiments. Further, AW = Der / De10.

[0060] Step 6, change the initial incident energy and initial incident angle of the incident electrons to obtain K sets of incident electron sets with different initial incident energies and different initial incident angles. Repeat steps 3 to 4 to calculate the secondary electron emission coefficient De1 k of the three-dimensional position model of the lattice space structure at different initial incident energies E k and different initial incident angles θ k .

[0061] In this embodiment, the initial incident energy of each incident electron in the k-th set of incident electron sets is E k and the initial incident angle is θ k , and the initial incident positions are respectively k = 1, 2, 3, ..., K, j = 1, 2, 3, ..., M k , M k represents the number of incident electrons in the k-th group of incident electron clusters.

[0062] Step 7, correct De1 according to the correction coefficient AW k to obtain the corrected secondary electron emission coefficient De of the three-dimensional position model of the lattice space structure at different initial incident energies E k and different initial incident angles θ k and output it. Among them, De k = AW · De1 k . k .

[0063] In this embodiment, it can be seen from the comparison of the experimental test results shown as follows Figure 3 that the accurate determination of the secondary electron emission coefficient of the random lattice is achieved by the present invention.

[0064] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention all fall within the protection scope of the technical solution of the present invention.

[0065] The content not detailedly described in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A method for determining the secondary electron emission coefficient of a random dot matrix, characterized in that Including: Step 1, establishing a three-dimensional position model of the lattice space structure; Step 2, determine the standard incident electron set; wherein, the standard incident electron set includes N incident electrons, and the initial incident energy of each incident electron in the standard incident electron set is E 0 , and the initial incident angle is θ 0 , and the initial incident positions are D i 0 ; E 0 = 100 eV, θ 0 = 0°, i = 1, 2, 3,..., N; Step 3, calculate to obtain that the number N0 of secondary electrons generated when N incident electrons with an initial incident energy of E 0 and an initial incident angle of θ 0 are incident on the three-dimensional position model of the lattice space structure; Step 4, according to N0, calculate the secondary electron emission coefficient De10 of the three-dimensional position model of the dot matrix space structure at the initial incident energy of E 0 , the initial incident angle of θ 0 when; Step 5, obtaining the experimental value Der of the secondary electron emission coefficient obtained from the experiment, and determining the correction coefficient AW according to Der and De10; Step 6: Change the initial incident energy and initial incident angle of the incident electrons to obtain K sets of incident electron sets with different initial incident energies and different initial incident angles. Among them, the initial incident energy of each incident electron in the k-th set of incident electron sets is E k , and the initial incident angle is θ k , and the initial incident positions are respectively k = 1, 2, 3,..., K, j = 1, 2, 3,..., M k , M k represents the number of incident electrons in the k-th set of incident electron sets; repeat Steps 3 - 4 to calculate the secondary electron emission coefficient De1 of the three-dimensional position model of the lattice space structure at different initial incident energies E k , different initial incident angles θ k ; k ; Step 7: Correct De1 according to the correction coefficient AW k to obtain the corrected secondary electron emission coefficient De at different initial incident energies E k , different initial incident angles θ k of the three-dimensional position model of the lattice space structure, k and output it.

2. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 1, characterized in that Establishing a three-dimensional position model of the lattice space structure, including: Determining the actual physical structure of the random lattice for 3D printing; Establishing a random lattice space structure model corresponding to the actual physical structure of the random lattice; Determining the position of the random lattice space structure indicated by the random lattice space structure model in the coordinate system O-XYZ, and sampling the random lattice space structure at a set step size Δd; According to the determined position of the random lattice space structure in the coordinate system O-XYZ, constructing a three-dimensional position model of the lattice space structure; and according to the sampling result of the random lattice space structure, marking the attribute of each three-dimensional position in the three-dimensional position model of the lattice space structure as vacuum or material; when determining that the attribute of the three-dimensional position is material, marking the secondary electron emission characteristics of the material; wherein, the secondary electron emission characteristics of the material include: the secondary electron emission model of the material and the model parameters.

3. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 2, characterized in that The coordinate system O-XYZ is a Cartesian coordinate system: the bottom of the outer shell of the actual physical structure of the random lattice is the XOY plane, and the upward extension direction of the actual physical structure of the random lattice is the Z axis.

4. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 2, characterized in that 1 nm ≤ Δd ≤ 1 μm.

5. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 1, characterized in that The calculated initial incident energy is E 0 and the initial incident angle is θ 0 When N incident electrons enter the three-dimensional position model of the lattice space structure, the number N0 of secondary electrons generated includes: Sub-step 31: According to the initial incident position of the i-th incident electron and the initial incident angle θ 0 , determine the linear motion trajectory A0 of the i-th incident electron, and determine the intersection point A of the linear motion trajectory A0 and the three-dimensional position model of the lattice space structure; Sub-step 32: According to the incident energy and incident angle when the i-th incident electron collides with intersection point A, and in combination with the secondary electron emission characteristics of the material at intersection point A, calculate the number N of secondary electrons generated by the collision si ; Sub-step 33: Determine whether the m-th secondary electron exits from the three-dimensional position model of the dot matrix space structure according to the exit position and exit angle of the m-th secondary electron; where 1 ≤ m ≤ N si ; Sub-step 34, if it is determined that the m-th secondary electron exits from the three-dimensional position model of the lattice space structure, then the count of the number of generated secondary electrons is incremented by 1; Sub-step 35, if it is determined that the m-th secondary electron does not exit from the three-dimensional position model of the lattice space structure, then determining the straight-line motion trajectory B0 of the m-th secondary electron, and determining the intersection point B of the straight-line motion trajectory B0 and the three-dimensional position model of the lattice space structure; calculating the number of secondary electrons generated by the collision of the m-th secondary electron according to sub-step 32. Sub-step 36, iterate sub-steps 31 to 35 until the entire motion process of all secondary electrons generated by the collision of N incident electrons with an initial incident energy of E 0 and an initial incident angle of θ 0 is completed, and determine the three-dimensional position model of the lattice space structure at an initial incident energy of E 0 and an initial incident angle of θ 0 when N incident electrons are incident, and the number N0 of secondary electrons generated 6. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 5, characterized in that, When the $i$-th incident electron collides with intersection point A, the incident energy is the initial incident energy $E$ of the $i$-th incident electron. 0 When the $i$-th incident electron collides with intersection point A, the incident angle is the angle between the straight-line motion trajectory $A_0$ and the normal line of the tangent plane of the random lattice space structure model at intersection point A.

7. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 5, characterized in that, Determining whether the m-th secondary electron exits from the three-dimensional position model of the lattice space structure according to the exit position and exit angle of the m-th secondary electron, including: Determining the straight-line motion trajectory B0 of the m-th secondary electron according to the initial incident position and initial incident angle of the m-th secondary electron; Judging whether there is an intersection point between the straight-line motion trajectory B0 and the three-dimensional position model of the lattice space structure; If it is determined that there is an intersection point between the straight-line motion trajectory B0 and the three-dimensional position model of the lattice space structure, then determining that the m-th secondary electron does not exit from the three-dimensional position model of the lattice space structure; otherwise, determining that the m-th secondary electron exits from the three-dimensional position model of the lattice space structure.

8. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 1, characterized in that De10 = N0 / N.

9. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 1, characterized in that AW = Der / De10.

10. The method for determining the secondary electron emission coefficient of a random dot matrix according to claim 1, characterized in that, De k = AW·De1 k .

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