Electron microscope chamber magnetic shielding method, computer readable storage medium and electronic device

Abstract

The application relates to the technical field of electromagnetic shielding, and particularly discloses an electron microscope chamber magnetic shielding method, a computer readable storage medium and an electronic device. The electron microscope chamber magnetic shielding method comprises a shielding shell, an electromagnetic compensation coil arranged in the shielding shell, a magnetic field compensation controller electrically connected with the electromagnetic compensation coil, a high-precision magnetic sensor and a computer electrically connected with the magnetic field compensation controller, the high-precision magnetic sensor is used for monitoring the magnetic field distribution in the shielding body in real time, and the magnetic field compensation controller is used for independently regulating and controlling the driving current of each electromagnetic compensation coil. The application solves the technical problem that the high-precision magnetic and electric experiment not only needs to shield the electromagnetic interference generated by the equipment in the adjacent room, but also needs to eliminate the electromagnetic interference field strength generated by the auxiliary equipment of the experimental equipment, and in the actual situation, the specific performance parameters of the electromagnetic equipment are often unclear, so that it is difficult to determine the effective electromagnetic interference elimination technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic shielding, in particular to an electron microscope chamber magnetic shielding method, a computer readable storage medium and an electronic device. BACKGROUND

[0002] In the field of high-precision electron microscope chambers, shielding technology is crucial to ensuring the accuracy and reliability of experiments. However, there are currently many technical difficulties.

[0003] In the magnetic shielding design process, it is usually only clear about the target value of magnetic shielding, but it is difficult to obtain the initial environmental magnetic field value. In particular, during the design process, experimental equipment is often in a confidential state, and the environmental magnetic field indicators during equipment use cannot be mastered. However, there are strict requirements for the magnetic field performance after shielding, that is, the direct current (DC) and alternating current (AC) magnetic fields in the X, Y, and Z directions of the electron microscope chamber need to be less than 20 nanotesla (nT), which poses a great challenge to the precise design of the magnetic shielding scheme.

[0004] In addition, high-precision magnetic and electric experiments not only need to shield the electromagnetic interference generated by adjacent room equipment, but also need to eliminate the electromagnetic interference field strength generated by the ancillary equipment of the experimental equipment. However, in actual situations, the specific performance parameters of electromagnetic equipment are often unclear, which makes it difficult to determine an effective electromagnetic interference elimination method.

[0005] Then, for a high-precision electron microscope chamber arranged continuously, it is required to have both magnetic shielding and electromagnetic shielding performance. However, there are currently few relevant design cases available for reference in the industry, and there is a lack of mature technical solutions and practical experience, which brings great difficulties to the construction of such electron microscope chambers and the design of the shielding system.

[0006] In view of the problem in the related art that high-precision magnetic and electric experiments not only need to shield the electromagnetic interference generated by adjacent room equipment, but also need to eliminate the electromagnetic interference field strength generated by the ancillary equipment of the experimental equipment, and in actual situations, the specific performance parameters of electromagnetic equipment are often unclear, making it difficult to determine an effective electromagnetic interference elimination method, no effective solution has been proposed yet. SUMMARY

[0007] The main purpose of the present application is to provide an electron microscope chamber magnetic shielding method, a computer readable storage medium and an electronic device, to solve the problem that high-precision magnetic and electric experiments not only need to shield the electromagnetic interference generated by adjacent room equipment, but also need to eliminate the electromagnetic interference field strength generated by the ancillary equipment of the experimental equipment, and in actual situations, the specific performance parameters of electromagnetic equipment are often unclear, making it difficult to determine an effective electromagnetic interference elimination method.

[0008] To achieve the above-mentioned purpose, the present application provides an electron microscope chamber magnetic shielding method.

[0009] The electron microscope chamber magnetic shielding method according to the application uses an electron microscope chamber magnetic shielding device for magnetic shielding;

[0010] The electron microscope chamber magnetic shielding device comprises:

[0011] A shielding shell;

[0012] An electromagnetic compensation coil arranged inside the shielding shell;

[0013] The electromagnetic compensation coil is electrically connected with a magnetic field compensation controller, the magnetic field compensation controller is electrically connected with a high-precision magnetic sensor and a computer respectively; the high-precision magnetic sensor is used for monitoring the magnetic field distribution in the shielding body in real time; the magnetic field compensation controller is used for independently regulating and controlling the driving current of each electromagnetic compensation coil; and the computer is used for reading the magnetic field data of the high-precision magnetic sensor and automatically generating a compensation magnetic field;

[0014] The automatically generated compensation magnetic field comprises:

[0015] Initializing parameters, determining a linear relationship matrix of the coil and the magnetic field through experiments and simulation;

[0016] Building a prediction model, the prediction model generates a multi-step magnetic field prediction value based on current current and disturbance prediction, and predicts the magnetic field distribution at the next moment;

[0017] Optimizing the prediction model;

[0018] Setting a reward function.

[0019] Further, building the linear relationship matrix comprises: setting the magnetic field sensitivity of the current of the jth electromagnetic compensation coil to the ith high-precision magnetic sensor as gij, the number of high-precision magnetic sensors as M, the number of electromagnetic compensation coils as N, and a MxN matrix as G, wherein N≥M;

[0020] Then the coupling matrix is:

[0021] Wherein, .

[0022] Further, the prediction model comprises: setting the magnetic field prediction vector at the k+1 moment as B(k+1), the coil current vector at the k moment as I(k), and the dynamic disturbance field intensity prediction value at the k moment as d(k),

[0023] .

[0024] Further, optimizing the prediction model comprises: setting the target magnetic field vector as Btarget, which is usually a zero field; and the current change amount at the k+j moment as ; the energy consumption penalty coefficient is λ; the prediction time domain is Hp, and the control time domain is Hc;

[0025] Then:

[0026] ;

[0027] The setting reward function comprises: setting a magnetic field error weight coefficient as α and a current change weight coefficient as β; wherein α represents the magnetic field error weight coefficient, emphasizing compensation accuracy; β represents the energy consumption change weight coefficient, inhibiting current mutation; α+β=1, generally taking α=0.7 and β=0.3, priority is given to guaranteeing magnetic field accuracy;

[0028] ;

[0029] Wherein,

[0030] ;

[0031] Preferably, the error size is determined and α is dynamically adjusted,

[0032] ;

[0033] Wherein, ;

[0034] According to the dynamic adjustment of the weights of α and β according to real-time errors, adaptive optimization can be realized.

[0035] Further, the automatically generated compensation magnetic field further comprises:

[0036] The tester device type and the interference parameter having a mapping relationship are structurally stored in the memory of the computer;

[0037] When the inputted device type to be tested is received, the target interference parameter corresponding to the device type to be tested is called according to the mapping relationship.

[0038] Further, a composite shielding door for shielding magnetic field and electric field is arranged on the wall in the shielding shell.

[0039] The composite shielding door comprises: a door frame arranged on the shielding shell, a left door leaf and a right door leaf oppositely arranged on the door frame; an internal shrinkage component is arranged on the left door leaf, and a door leaf bolt is arranged on the right door leaf.

[0040] Further, a copper elastic spring sheet is further arranged on the door frame.

[0041] In order to achieve the above-mentioned purpose, according to another aspect of the present application, a storage medium is provided.

[0042] According to the storage medium of the application, the computer readable storage medium stores a computer program, wherein the computer program is configured to execute the electron microscope chamber magnetic shielding method when running.

[0043] In order to achieve the above-mentioned purpose, according to another aspect of the application, an electronic device is provided.

[0044] According to the electron microscope chamber of the application, a memory and a processor are included, the memory stores a computer program, and the processor is configured to run the computer program to execute the electron microscope chamber magnetic shielding method.

[0045] In the embodiment of the application, the environment magnetic field model is constructed, and the electromagnetic compensation coils are arranged in the environment magnetic field model to automatically generate compensation magnetic fields from the X, Y and Z three orthogonal directions, and the shielding shell is shielded; the electromagnetic compensation coils are arranged inside the shielding shell; the electromagnetic compensation coils are electrically connected with a magnetic field compensation controller, the magnetic field compensation controller is electrically connected with a high-precision magnetic sensor and a computer; the high-precision magnetic sensor is used to monitor the magnetic field distribution in the shielding body in real time; the magnetic field compensation controller is used to independently control the driving current of each electromagnetic compensation coil; the computer is used to read the magnetic field data of the high-precision magnetic sensor and automatically generate a compensation magnetic field; the automatically generated compensation magnetic field includes: initializing parameters, determining the linear relationship matrix of the coil and the magnetic field through experiments and simulation; constructing a prediction model, the prediction model generates multi-step magnetic field prediction values based on the current and the interference prediction, and predicts the magnetic field distribution at the next moment; the prediction model is optimized; a reward function is set; the purpose of active compensation magnetic field is achieved, so that the technical effect of automatically generating a compensation magnetic field according to the field strength in the electron microscope chamber is realized, and the technical problem that the high-precision magnetic and electric experiments not only need to shield the electromagnetic interference generated by the adjacent room equipment, but also need to eliminate the electromagnetic interference field strength generated by the auxiliary equipment of the experimental equipment is solved, and in actual situation, the specific performance parameters of the electromagnetic equipment are often unclear, which causes the difficulty in determining the effective elimination of electromagnetic interference. BRIEF DESCRIPTION OF DRAWINGS

[0046] The accompanying drawings, which form a part of this application, are used to provide further understanding of the application, so that the other features, purposes and advantages of the application become more obvious. The schematic embodiment drawings of the application and their descriptions are used to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0047] Figure 1 is a schematic view of a shielding shell according to an embodiment of the application;

[0048] Figure 2 is a front view of a composite shielding door according to an embodiment of the application;

[0049] Figure 3 This is a cross-sectional view of a composite shielding door according to an embodiment of this application;

[0050] Figure 4 yes Figure 3 A magnified view of part A in the middle;

[0051] Figure 5 This is a schematic diagram of an electromagnetic compensation coil according to an embodiment of the present invention;

[0052] Figure 6 This is a schematic diagram of the overall routing of the cable trays according to an embodiment of the present invention;

[0053] Figure 7 This is a reference schematic diagram of the coil mounting position according to an embodiment of the invention.

[0054] Figure Labels

[0055] 1. Door frame; 2. Left door leaf; 3. Right door leaf; 4. Internal tightening component; 5. Hinge; 6. Copper elastic spring; 8. Door leaf latch. Detailed Implementation

[0056] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0057] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0058] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0059] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0060] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0061] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0062] like Figures 1-7 As shown, this application relates to a magnetic shielding method for an electron microscope chamber, which includes:

[0063] S1. An environmental magnetic field model constructed based on environmental magnetic field measurement data from a simulated electron microscope chamber.

[0064] S1.1 Select the electron microscope room as the measurement site for simulating the experimental environment. The environmental characteristics of the measurement site should be as close as possible to the actual environmental conditions of the future high-precision electron microscope room.

[0065] Two measurement points are selected in the electron microscope room. The selection of measurement points should take into account factors such as the layout of the electron microscope room and the distribution of possible magnetic field interference sources, so as to ensure that the measurement results can accurately reflect the overall magnetic field environment of the electron microscope room.

[0066] S1.2. Set up a distribution box at a distance of 3.0m from each measuring point and use it as a simulation instrument. The arrangement and location of the distribution box should be consistent to ensure the comparability of the measurement data.

[0067] S1.3 Use professional magnetic field measuring equipment to measure the DC and AC magnetic field values ​​in the X, Y, and Z directions of the shielded room respectively; during the measurement process, ensure the accuracy and stability of the measuring equipment, operate according to the prescribed measurement methods and procedures, and record the magnetic field values ​​at different directions and distances (such as 0.5m, 1.5m, 2.5m).

[0068] S1.4. Organize and analyze the large amount of magnetic field data obtained from the measurement, and use statistical methods and relevant magnetic field analysis models to calculate key parameters such as the average value and fluctuation range of the magnetic field in the shielded room.

[0069] Based on the analysis results, it was determined that the initial ambient magnetic field of the electron microscope chamber without shielding was less than 200 nT. Based on this, a passive shielding system and an active compensation system were designed to make the magnetic field inside the electron microscope chamber less than or equal to 20 nT after shielding.

[0070] S1.5 Record the actual magnetic field values ​​measured in the simulation in detail and organize them into charts. At the same time, create corresponding documents for archiving so that they can be consulted and referenced in the shielding design and experimental process.

[0071] S2. Construct a shielding system for the electron microscope chamber based on an environmental magnetic field model, and complete the basic architecture of the shielding system;

[0072] S2.1. Determine the parameters of the shielding shell (including location, thickness, and layout) based on the environmental magnetic field model, and construct the shielding shell. Verify through calculation that the shielding shell is made of 10mm or 14mm thick Q235 low carbon steel plate, where 10mm can achieve an electromagnetic shielding performance of 38dB, meeting the magnetic shielding requirements. Permalloy magnetic shielding mesh can be attached to the surface of the shielding shell to work together with the Q235 low carbon steel plate to shield the magnetic field.

[0073] S2.2 An electromagnetic compensation coil is set inside the shielding shell according to the magnetic field distribution. The current parameter of the electromagnetic compensation coil is adjusted in real time during high-precision electromagnetic experiments, so that the electromagnetic compensation coil can dynamically solve the magnetic field interference problem. It is worth noting that this embodiment mainly involves interference magnetic field compensation.

[0074] The installation of electromagnetic compensation coils inside the shielding housing includes: installing electromagnetic compensation coils in at least three directions on the inner wall of the shielding housing to generate compensation magnetic fields in the three orthogonal directions of X, Y, and Z respectively, and to cancel the anisotropic components of the interference field in real time; the electromagnetic compensation coils can be selected from orthogonal Helmholtz coils, solenoids, etc.

[0075] The electromagnetic compensation coil is connected to a magnetic field compensation controller, the magnetic field compensation controller is electrically connected to a high-precision magnetic sensor, and the magnetic field compensation controller is connected to a computer.

[0076] High-precision magnetic sensors are used to monitor the magnetic field distribution inside the shield in real time. Each preset point should have a sensor or obtain a sufficient number of spatial sampling points through interpolation. The magnetic field compensation controller is used to independently regulate the drive current of each electromagnetic compensation coil. The computer is used to read the magnetic field data from the high-precision magnetic sensors and calculate the required compensation magnetic field for each area in real time, derive the required current value for each coil, and send current adjustment commands to the magnetic field compensation controller.

[0077] Specifically, the electromagnetic compensation coils are connected to the magnetic field compensation controller via a fiber-optic isolated CAN FD bus. Each electromagnetic compensation coil is equipped with an independent H-bridge driver module (such as the TI DRV8848), which supports ±10A peak current and a PWM frequency of 20kHz, enabling precise control of the electromagnetic compensation coil current. The magnetic field compensation controller sends control commands to the H-bridge driver module via the CAN FD bus. The commands are encapsulated in CAN FD frames (64-byte payload) and CRC checksums are used to ensure command integrity. A retransmission mechanism is also included to handle potential communication errors. Fiber optic isolation further enhances the communication's anti-interference capability, with a transmission delay of less than 1μs, ensuring fast and stable control of the coils by the controller.

[0078] The magnetic field compensation controller is electrically connected to a high-precision magnetic sensor via a digitally isolated RS-485 bus. Each high-precision magnetic sensor is connected to the bus as an independent node. The high-precision magnetic sensor has a built-in signal conditioning circuit (such as an instrumentation amplifier AD8421) to process the raw signal, including amplification (adjustable gain from 1 to 1000 times), filtering, and other operations to ensure signal quality and stability. The processed signal is converted into a digital signal by a 24-bit Δ-Σ ADC (such as ADS131M08) and then transmitted to the magnetic field compensation controller for preprocessing. The preprocessing functions include digital filtering (FIR / IIR), baseline correction (to eliminate the effects of temperature drift), and outlier removal to reduce the amount of data and improve data reliability.

[0079] The magnetic field compensation controller connects to the computer via Gigabit Ethernet. Gigabit Ethernet provides high-speed data transmission capabilities, enabling the controller to upload large amounts of magnetic field data to the computer in real time and receive control parameters from the computer. Simultaneously, the magnetic field data collected by the high-precision magnetic sensor can be quickly and accurately transmitted to the magnetic field compensation controller. After processing, the controller precisely controls the electromagnetic compensation coil to generate the compensation magnetic field via the CAN FD bus. The controller and computer also interact via Ethernet to achieve system monitoring, configuration, and management functions. The computer is located in the equipment room, which is outside the shielded enclosure.

[0080] Through the above connection method, the magnetic field data collected by the high-precision magnetic sensor can be quickly and accurately transmitted to the magnetic field compensation controller. After processing, the controller precisely controls the electromagnetic compensation coil to generate a compensation magnetic field through the CAN FD bus. At the same time, the controller and the computer exchange data via Ethernet.

[0081] The structure and arrangement of the electromagnetic compensation coil are referenced. Figures 5-7 ,in Figure 5 It is a single-axis coil; Figure 6 Black represents the room frame, blue represents the X-axis groove, red represents the Y-axis groove, yellow represents the Z-axis groove, and green represents the groove connecting the room to the outside room. Figure 7 In the blue section, the X-axis slot is represented by blue, the Y-axis slot by red, and the Z-axis slot by yellow. Single-axis coils are arranged in the X-axis, Y-axis, and Z-axis slots, with a coil density of approximately 1 meter intervals. 3 0.5m 3 0.2m 3 The number of turns can be 50-150.

[0082] In step S2.2, the computer reads the magnetic field data from the high-precision magnetic sensor and calculates the required compensation magnetic field for each region in real time, and derives the required current value for each coil, including:

[0083] S2.2.1 Initialize parameters and determine the linear relationship matrix between the coil and the magnetic field through experiments and simulations;

[0084] Let gij be the sensitivity of the current of the j-th electromagnetic compensation coil to the magnetic field of the ith high-precision magnetic sensor, M be the number of high-precision magnetic sensors, N be the number of electromagnetic compensation coils, and G be the M×N dimensional matrix, where N≥M;

[0085] The coupling matrix formula is: ;

[0086] in, ;

[0087] g11 refers to the sensitivity of the first coil to the first sensor; gij represents the change in the magnetic field at sensor i when the current of coil j changes by 1A, that is, the sensitivity of the current of the j-th electromagnetic compensation coil to the magnetic field at the i-th magnetic field measurement point. This represents the change in magnetic field at the i-th magnetic field measurement point; This represents the change in current of the j-th coil. By setting the coupling matrix, mutual inductance interference between electromagnetic compensation coils can be eliminated, improving compensation accuracy. The linear influence of each coil on the magnetic field can be quantified, providing input for the control algorithm and ensuring that subsequent predictions and optimizations are based on real data. The pseudo-inverse of the matrix can eliminate cross-interference between multiple coils, improving compensation accuracy. It is especially suitable for solving the problem that the electromagnetic compensation coils are close together in high-interference areas, further increasing the possibility of interference.

[0088] S2.2.2 Construct a prediction model, generate multi-step magnetic field prediction values ​​based on the current current and disturbance prediction, and predict the magnetic field distribution at the next moment;

[0089] Let the predicted magnetic field vector at time k+1 be B(k+1), the coil current vector at time k be I(k), and the predicted dynamic disturbance field strength at time k be d(k).

[0090] ;

[0091] By planning the current adjustment strategy in advance, the response delay can be reduced, and the unmodeled environmental noise can be offset by dynamically predicting the field strength.

[0092] In this embodiment, as another optional implementation, the automatic generation of the compensation magnetic field further includes: structurally storing test device types and interference parameters with mapping relationships in the computer's memory; when the input test device type is received, calling the target interference parameters corresponding to the test device type according to the mapping relationship.

[0093] By storing the test device types and interference parameters with a mapping relationship in a structured manner, it is possible to determine the corresponding target interference parameters according to the type of the device under test; considering the correlation between device type and magnetic field compensation, a compensation magnetic field can also be automatically generated based on this parameter.

[0094] In some embodiments, the type of test device can also be considered as a factor affecting magnetic field compensation, and combined with predictions through predictive models to further improve the accuracy of magnetic field compensation.

[0095] S2.2.3 Optimize the prediction model to balance magnetic field accuracy and energy consumption;

[0096] Let the target magnetic field vector be Btarget, which is usually zero; the change in current at time k+j is... The energy consumption penalty coefficient is λ; the prediction time domain is Hp, and the control time domain is Hc.

[0097] but:

[0098] If λ=0.1, it indicates that the system prioritizes magnetic field accuracy and allows for larger current fluctuations; if λ=0.5, it indicates that the system prioritizes energy saving and suppresses sudden current changes. The prediction time domain Hp represents how many time steps the controller predicts the system state in each step. For example, Hp=10 predicts the magnetic field change in the next 10ms, used to anticipate magnetic field interference trends and optimize the compensation strategy of the electromagnetic compensation coil. The control time domain Hc represents how many time steps the controller optimizes the control input in each step. For example, Hc=5 optimizes a 5-step current adjustment strategy (corresponding to the next 5ms). By limiting the number of optimized variables, the real-time calculation load is reduced. The control output after Hc retains the last optimized value by default, for example, I5=I6=...=I... 10 Within each control cycle, based on the current magnetic field data and disturbance prediction, an optimal current command is generated to quickly cancel out transient disturbances and respond rapidly to them, ensuring real-time performance; this is achieved by minimizing magnetic field errors. To ensure the residual magnetic field meets the requirements (i.e., less than 20 nT), a penalty current change is applied. This can reduce power consumption and heat load. By setting an energy consumption penalty coefficient in the objective function, the magnetic field accuracy and energy consumption can be balanced, and dynamic weight adjustment can be achieved to reach the global optimal solution and avoid falling into the local optimal trap.

[0099] Preferably, Hc ≤ Hp; when Hc = Hp, the control input of all prediction steps is optimized, resulting in the largest computational load but the highest accuracy; when Hc < Hp, some accuracy is sacrificed to improve real-time performance.

[0100] S2.2.4. Set a reward function r(k) to quantify the quality of control actions, guide the update of reinforcement learning strategies, dynamically adjust the control strategy through reinforcement learning, optimize long-term cumulative performance, and optimize global performance.

[0101] Let the magnetic field error weighting coefficient be α and the current change weighting coefficient be β; where α represents the magnetic field error weighting coefficient, emphasizing compensation accuracy; β represents the energy consumption change weighting coefficient, suppressing sudden current changes; α+β=1, and generally the values ​​of α=0.7 and β=0.3 are taken to prioritize magnetic field accuracy;

[0102] ;

[0103] in,

[0104] ;

[0105] Preferably, the error magnitude is determined and α is dynamically adjusted.

[0106] ;

[0107] in, ;

[0108] By dynamically adjusting the weights of α and β based on real-time error, adaptive optimization can be achieved. Furthermore, even when the magnetic field changes due to aging of the learning device or environmental drift, the compensation performance can still be maintained, which is beneficial for long-term stability compensation.

[0109] The linear relationship matrix between the coil and the magnetic field, determined through experiments and simulations, provides a solid physical foundation for the prediction model and optimization process, ensuring the reliability of input data and effectively avoiding the accumulation of errors in subsequent calculations. Based on this matrix, the prediction model generates multi-step magnetic field predictions by combining current and disturbance predictions, achieving forward-looking control and reducing response delay. Simultaneously, the prediction model and the reward function work together to continuously cover various possible disturbance modes across the entire time domain through long-term learning. The reward function, through long-term strategy optimization, dynamically adjusts weights based on real-time errors and system operating conditions, guiding the system to make adaptive decisions in complex and ever-changing environments, effectively coping with various complex environmental changes. Through the close collaboration of the above components, the system successfully achieves an effective combination of accuracy, real-time performance, energy efficiency, and adaptability, enabling stable operation in the electron microscope laboratory setting.

[0110] S3. Install shielding doors on the walls inside the shielding enclosure;

[0111] The composite shielding door is supported by 14mm thick Q235 low carbon steel. Q235 low carbon steel has magnetic shielding, electromagnetic shielding and radiation protection functions at the same time; the best magnetic permeability of low carbon steel is selected as 4000.

[0112] The composite shielded door includes: a door frame 1 installed on the shielding shell, and a left door leaf 2 and a right door leaf 3 installed opposite to each other on the door frame 1; hinges 5 are respectively connected to the left door leaf 2 and the right door leaf 3; an internal tightening component 4 is provided on the left door leaf 2, and a door leaf latch 8 with up-and-down linkage is provided on the right door leaf to fix the right door leaf 3 to the door frame 1. Copper elastic springs 6 are also installed around the door frame 1, which can ensure reliable electrical contact between the door frame 1 and the door leaf, ensuring a good shielding effect.

[0113] As can be seen from the above description, in this embodiment, an environmental magnetic field model is constructed, and electromagnetic compensation coils are set in the environmental magnetic field model to automatically generate compensation magnetic fields from three orthogonal directions (X, Y, and Z). This is achieved through a shielding shell; electromagnetic compensation coils are set inside the shielding shell; each electromagnetic compensation coil is electrically connected to a magnetic field compensation controller, which is electrically connected to a high-precision magnetic sensor and a computer; the high-precision magnetic sensor is used to monitor the magnetic field distribution within the shielding shell in real time; the magnetic field compensation controller is used to independently control the drive current of each electromagnetic compensation coil; the computer is used to read the magnetic field data from the high-precision magnetic sensor and automatically generate compensation magnetic fields; the automatic generation of compensation magnetic fields... The process includes: initializing parameters, determining the linear relationship matrix between the coil and the magnetic field through experiments and simulations; constructing a prediction model, which generates multi-step magnetic field prediction values ​​based on the current current and interference predictions, and predicts the magnetic field distribution at the next moment; optimizing the prediction model; setting a reward function; achieving the goal of actively compensating for the magnetic field, thereby realizing the technical effect of adaptively generating a compensating magnetic field based on the field strength in the electron microscope chamber, and thus solving the technical problem that high-precision magnetoelectric experiments not only need to shield against electromagnetic interference generated by equipment in adjacent rooms, but also need to eliminate the electromagnetic interference field strength generated by auxiliary equipment of the experimental equipment, and in practice, the specific performance parameters of electromagnetic equipment are often unknown, making it difficult to determine an effective way to eliminate electromagnetic interference.

[0114] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A magnetic shielding method for an electron microscope chamber, characterized in that, Magnetic shielding was performed using a magnetic shielding device in the electron microscope chamber. The magnetic screen device for the electron microscope chamber includes: Shielding housing; An electromagnetic compensation coil is installed inside the shielding housing; The electromagnetic compensation coil is electrically connected to a magnetic field compensation controller, which is electrically connected to a high-precision magnetic sensor and a computer. The high-precision magnetic sensor is used to monitor the magnetic field distribution inside the shield in real time. The magnetic field compensation controller is used to independently adjust the drive current of each electromagnetic compensation coil. The computer is used to read the magnetic field data of the high-precision magnetic sensor and automatically generate a compensation magnetic field. The automatically generated compensation magnetic field includes: Initialize parameters and determine the linear relationship matrix between the coil and the magnetic field through experiments and simulations; A prediction model is constructed, which generates multi-step magnetic field prediction values ​​based on the current current and disturbance predictions, and predicts the magnetic field distribution at the next moment. The prediction model is optimized; Set a reward function; The prediction model is constructed as follows: Let the magnetic field prediction vector at time k+1 be B(k+1), the coil current vector at time k be GI(k), and the dynamic disturbance field strength prediction value at time k be d(k). ； Optimizing the prediction model includes: Let the target magnetic field vector be Btarget; the current change at time k+j is... The energy consumption penalty coefficient is λ; the prediction time domain is Hp, and the control time domain is Hc. but: ； The setting of the reward function r(k) includes: setting the magnetic field error weighting coefficient as α and the current change weighting coefficient as β; where α+β=1; in, Determine the magnitude of the error and dynamically adjust α. in, Adaptive optimization can be achieved by dynamically adjusting the weights of α and β based on real-time error.

2. The magnetic shielding method for an electron microscope chamber according to claim 1, characterized in that, Constructing the linear relationship matrix includes: Let gij be the sensitivity of the current of the j-th electromagnetic compensation coil to the magnetic field of the ith high-precision magnetic sensor, M be the number of high-precision magnetic sensors, N be the number of electromagnetic compensation coils, and G be the M×N dimensional matrix, where N≥M; The coupling matrix is ​​then: in, , gij represents the change in magnetic field at sensor i when the current of coil j changes by 1A, that is, the sensitivity of the current of the j-th electromagnetic compensation coil to the magnetic field at the i-th magnetic field measurement point. This represents the change in magnetic field at the i-th magnetic field measurement point; This represents the change in current of the j-th coil.

3. The magnetic shielding method for an electron microscope chamber according to claim 1, characterized in that, The automatically generated compensation magnetic field also includes: The computer's memory contains structured storage of test device types and interference parameters with mapping relationships; When the type of device under test is received, the target interference parameters corresponding to the type of device under test are called according to the mapping relationship.

4. The magnetic shielding method for an electron microscope chamber according to claim 1, characterized in that, The walls inside the shielding shell are equipped with composite shielding doors that provide both magnetic and electric field shielding. The composite shielding door includes: a door frame installed on the shielding shell, a left door leaf and a right door leaf installed opposite each other on the door frame; the left door leaf is provided with an internal tightening component, and the right door leaf is provided with a door leaf latch.

5. The magnetic shielding method for an electron microscope chamber according to claim 4, characterized in that, Copper elastic springs are also installed around the perimeter of the door frame.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein the computer program is configured to execute the electron microscope chamber magnetic shielding method according to any one of claims 1 to 3 when it is run.

7. An electronic device comprising: A memory and a processor, characterized in that the memory stores a computer program, wherein the processor is configured to run the computer program to perform the electron microscope chamber magnetic shielding method according to any one of claims 1 to 3.

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