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

Abstract

The invention 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; the electromagnetic compensation coil is arranged in the shielding shell; the electromagnetic compensation coil is electrically connected with a magnetic field compensation controller, and the magnetic field compensation controller is electrically connected with a high-precision magnetic sensor and a computer. The high-precision magnetic sensor is used for monitoring 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 technical problems that electromagnetic interference generated by adjacent room equipment needs to be shielded and electromagnetic interference field intensity generated by accessory equipment of experimental equipment needs to be eliminated in a high-precision magnetoelectric experiment, and the electromagnetic interference is difficult to determine and effectively eliminate due to the fact that specific performance parameters of the electromagnetic equipment are often not clear in the actual situation are solved.

Description

Technical Field

[0001] The present application relates to the technical field of electromagnetic shielding, and more particularly, to a magnetic shielding method for an electron microscope room, a computer-readable storage medium, and an electronic device. Background Art

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

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

[0004] In addition, high-precision magnetoelectric experiments not only need to shield the electromagnetic interference generated by equipment in adjacent rooms, but also need to eliminate the electromagnetic interference field strength generated by the auxiliary equipment of the experimental equipment. However, in actual situations, the specific performance parameters of electromagnetic equipment are often unknown, which makes it difficult to determine an effective method for eliminating electromagnetic interference.

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

[0006] In view of the problem that in the related art, high-precision magnetoelectric experiments not only need to shield the electromagnetic interference generated by equipment in adjacent rooms, but also need to eliminate the electromagnetic interference field strength generated by the auxiliary equipment of the experimental equipment, and in actual situations, the specific performance parameters of electromagnetic equipment are often unknown, resulting in difficulty in determining an effective method for eliminating electromagnetic interference, no effective solution has been proposed yet. Summary of the Invention

[0007] The main purpose of the present application is to provide a magnetic shielding method for an electron microscope room, a computer-readable storage medium, and an electronic device to solve the problem that in high-precision magnetoelectric experiments, it is difficult to determine an effective method for eliminating electromagnetic interference because it is necessary to shield the electromagnetic interference generated by equipment in adjacent rooms, eliminate the electromagnetic interference field strength generated by the auxiliary equipment of the experimental equipment, and in actual situations, the specific performance parameters of electromagnetic equipment are often unknown.

[0008] To achieve the above object, the present application provides a magnetic shielding method for an electron microscope room.

[0009] According to the electron microscope room magnetic shielding method of the present application, magnetic shielding is performed using an electron microscope room magnetic shielding device; The electron microscope room magnetic shielding device includes: A shielding housing; An electromagnetic compensation coil disposed inside the shielding housing; The electromagnetic compensation coil is electrically connected to a magnetic field compensation controller, and the magnetic field compensation controller is respectively 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 regulate 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 automatic generation of the compensation magnetic field includes: Initializing parameters, and 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 and interference predictions, and predicts the magnetic field distribution at the next moment; Optimizing the prediction model; Setting a reward function.

[0010] Further, constructing the linear relationship matrix includes: Let the magnetic field sensitivity of the current of the jth electromagnetic compensation coil to the ith high-precision magnetic sensor be gij, the number of high-precision magnetic sensors be M, the number of electromagnetic compensation coils be N, and the M×N-dimensional matrix be G, where N≥M; Then the coupling matrix is: Where, .

[0011] Further, constructing the prediction model includes: Let the magnetic field prediction vector at the (k + 1)th moment be B(k + 1), the coil current vector at the kth moment be I(k), and the predicted value of the dynamic interference field strength at the kth moment be d(k), .

[0012] Further, optimizing the prediction model includes: Let the target magnetic field vector be Btarget, usually a zero field; the current change amount at the (k + j)th moment be ; the energy consumption penalty coefficient be λ; the prediction time domain be Hp, and the control time domain be Hc; Then: ; The said setting of the reward function includes: setting the magnetic field error weight coefficient as α and the current change weight coefficient as β; where α represents the magnetic field error weight coefficient, emphasizing the compensation accuracy; β represents the energy consumption change weight coefficient, suppressing the sudden change of current; α + β = 1, generally taking the value of α = 0.7 and β = 0.3, giving priority to ensuring the magnetic field accuracy. ; Among them, ; Preferably, determine the error magnitude and dynamically adjust α. ; Among them, ; Dynamically adjusting the weights of α and β according to the real-time error can achieve adaptive optimization.

[0013] Furthermore, the said automatically generating the compensation magnetic field further includes: The test device types and interference parameters with mapping relationships are structurally stored in the memory of the computer. When receiving the input of the test device type to be tested, call the target interference parameter corresponding to the test device type to be tested according to the mapping relationship.

[0014] Furthermore, a composite shielding door for magnetic field and electric field shielding is provided on the wall inside the shielding housing. The composite shielding door includes: a door frame installed on the shielding housing, a left door leaf and a right door leaf oppositely installed on the door frame; an internal tightening component is provided on the left door leaf, and a door leaf bolt is provided on the right door leaf.

[0015] Furthermore, copper elastic reed pieces are also installed on the periphery of the door frame.

[0016] In order to achieve the above object, according to another aspect of the present application, a storage medium is provided.

[0017] According to the storage medium of the present application, a computer program is stored in the computer-readable storage medium, where the computer program is set to execute the electron microscope room magnetic shielding method when running.

[0018] In order to achieve the above object, according to another aspect of the present application, an electronic device is provided.

[0019] The electron microscope room according to the present application includes: a memory and a processor, a computer program is stored in the memory, where the processor is set to run the computer program to execute the electron microscope room magnetic shielding method.

[0020] In the embodiments of the present application, an environmental magnetic field model is constructed, and electromagnetic compensation coils are arranged in the environmental magnetic field model to automatically generate compensation magnetic fields from three orthogonal directions of X, Y, and Z respectively. Through a shielding housing; electromagnetic compensation coils arranged inside the shielding housing; the electromagnetic compensation coils are electrically connected to a magnetic field compensation controller, and the magnetic field compensation controller is electrically connected to a high-precision magnetic sensor and a computer respectively; 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 regulate 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 automatic generation of the compensation magnetic field includes: initializing parameters, determining the linear relationship matrix between the coil and the magnetic field through experiments and simulations; constructing a prediction model, the prediction model is based on the current and interference predictions to generate multi-step magnetic field prediction values and predict the magnetic field distribution at the next moment; optimizing the prediction model; setting a reward function; achieving the purpose of actively compensating the magnetic field, thereby realizing the technical effect of being able to adaptively generate a compensation magnetic field according to the field strength in the electron microscope room, and further solving the technical problem that it is difficult to determine effective electromagnetic interference elimination because high-precision magnetoelectric experiments not only need to shield the electromagnetic interference generated by equipment in adjacent rooms, but also need to eliminate the electromagnetic interference field strength generated by the auxiliary equipment of the experimental equipment, and in actual situations, the specific performance parameters of electromagnetic equipment are often unknown. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings forming a part of this application are used to provide a further understanding of this application, making other features, objects, and advantages of this application more apparent. The schematic embodiments of the drawings of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings: Figure 1 is a schematic diagram of a shielding housing according to an embodiment of the present application; Figure 2 is a front view of a composite shielding door according to an embodiment of the present application; Figure 3 is a cross-sectional view of a composite shielding door according to an embodiment of the present application; Figure 4 is Figure 3 a partial enlarged view of part A in; Figure 5 is a schematic diagram of an electromagnetic compensation coil according to an embodiment of the present invention; Figure 6 is a schematic diagram of the overall running direction of a wire groove according to an embodiment of the present invention; Figure 7 is a reference schematic diagram of the coil installation position according to an embodiment of the invention.

[0022] REFERENCE SIGNS 1. Door frame; 2. Left door leaf; 3. Right door leaf; 4. Internal tightening component; 5. Hinge; 6. Copper elastic reed; 8. Door leaf bolt. Detailed implementation manner

[0023] In order to enable those skilled in the art of this technology to better understand the solution of this application, the following will clearly and completely describe the technical solution in the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of this application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of this application described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0025] In this application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit that the indicated device, element or component must have a specific orientation, or be constructed and operated in a specific orientation.

[0026] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0027] In addition, the terms "installed", "set up", "provided with", "connected", "linked", "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or an internal connection between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will detail this application with reference to the drawings and in conjunction with the embodiments.

[0029] As Figures 1-7 shown, this application relates to a method for magnetic shielding of an electron microscope room, and the method for magnetic shielding of the electron microscope room includes: S1. Construct an environmental magnetic field model based on the measured data of the environmental magnetic field of the simulated electron microscope room.

[0030] S1.1. Select the electron microscope room as the measurement site for the simulated experimental environment, and 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; Select two measurement points in the electron microscope room. The selection of the measurement points needs to comprehensively consider factors such as the layout of the electron microscope room and the distribution of possible magnetic field interference sources to ensure that the measurement results can more accurately reflect the overall magnetic field environment of the electron microscope room.

[0031] S1.2. Arrange distribution boxes at a distance of 3.0 m from each measurement point and use them as simulated instruments. The arrangement methods and positions of the distribution boxes should be kept consistent to ensure the comparability of the measurement data.

[0032] S1.3. Use professional magnetic field measurement equipment to measure the DC and AC magnetic field values in the X, Y, and Z directions in the shielding room respectively; during the measurement process, ensure the accuracy and stability of the measurement equipment, operate according to the specified measurement methods and procedures, and record the magnetic field values in different directions and at different distances (such as 0.5 m, 1.5 m, 2.5 m).

[0033] S1.4. Sort out and analyze the large amount of measured magnetic field data, 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 shielding room.

[0034] According to the analysis results, it is determined that the initial environmental magnetic field of the electron microscope room without shielding is less than 200 nT. Based on this, a passive shielding system and an active compensation system are designed so that the internal magnetic field of the electron microscope room after shielding is less than or equal to 20 nT.

[0035] S1.5. Record the actual magnetic field values measured by simulation in detail, organize them in the form of charts, and establish corresponding documents for archiving for subsequent reference and consultation during shielding design and experimental processes.

[0036] S2. Based on the environmental magnetic field model, construct a main-passive collaborative shielding system for the electron microscope room to complete the basic structure of the shielding system; S2.1. Determine the parameters of the shielding shell (including position, thickness, and layout) based on the environmental magnetic field model, and build the shielding shell; verify through calculation that the shielding shell is made of Q235 low-carbon steel plate with a thickness of 10 mm or 14 mm, and 10 mm can achieve an electromagnetic shielding performance of 38 db, meeting the magnetic shielding requirements; a permalloy magnetic shielding net can be attached to the surface of the shielding shell to cooperate with the Q235 low-carbon steel plate to shield the magnetic field; S2.2. Set electromagnetic compensation coils inside the shielding shell according to the magnetic field distribution. During high-precision electromagnetic experiments, the current parameters of the electromagnetic compensation coils are adjusted in real time so that the electromagnetic compensation coils can solve the problem of dynamic magnetic field interference; it should be noted that this embodiment mainly involves interference magnetic field compensation; Setting electromagnetic compensation coils inside the shielding shell includes: installing electromagnetic compensation coils in at least three directions on the inner wall of the shielding shell to generate compensation magnetic fields in the X, Y, and Z three orthogonal directions respectively to cancel the anisotropic components of the interference field in real time; the electromagnetic compensation coils can be selected as orthogonal Helmholtz coils, solenoids, etc.

[0037] The electromagnetic compensation coils are 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; The high-precision magnetic sensor is used to monitor the magnetic field distribution inside the shielding body in real time. There should be sensors at each preset point or sufficient spatial sampling points can be obtained through interpolation; 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 calculate the required compensation magnetic fields in each area in real time, and deduce the current values required for each coil, and send a current adjustment instruction to the magnetic field compensation controller.

[0038] Specifically, the electromagnetic compensation coil is connected to a magnetic field compensation controller through a fiber-optic isolated CAN FD bus. Each group of electromagnetic compensation coils is equipped with an independent H-bridge drive module (such as TI DRV8848). This drive module supports a peak current of ±10A and a PWM frequency of 20kHz, enabling precise control of the current in the electromagnetic compensation coil. The magnetic field compensation controller sends control instructions to the H-bridge drive module through the CAN FD bus. The instructions are encapsulated in the form of CAN FD frames (64-byte payloads) and use CRC checks to ensure the integrity of the instructions. At the same time, it has a retransmission mechanism to handle possible communication errors. The fiber-optic isolation method further enhances the anti-interference ability of the communication, with a transmission delay of less than 1μs, ensuring fast and stable control of the coil by the controller.

[0039] The magnetic field compensation controller is electrically connected to a high-precision magnetic sensor through a digital isolation RS-485 bus; each high-precision magnetic sensor is connected to the bus as an independent node. The high-precision magnetic sensor is built with a signal conditioning circuit (such as instrumentation amplifier AD8421) to process the original signal, including operations such as amplification (gain adjustable from 1 to 1000 times) and filtering, ensuring the quality and stability of the signal. The processed signal is converted into a digital signal through 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 (eliminating the influence of temperature drift), and outlier rejection, etc., to reduce the data volume and improve the reliability of the data.

[0040] The magnetic field compensation controller is connected to a computer through Gigabit Ethernet. Gigabit Ethernet provides high-speed data transmission capabilities, meeting the requirements of the controller for real-time uploading of a large amount of magnetic field data to the computer and receiving control parameters issued by the computer; at the same time, the magnetic field data collected by the high-precision magnetic sensor can be quickly and accurately transmitted to the magnetic field compensation controller. After being processed by the controller through calculations, it precisely controls the electromagnetic compensation coil to generate a compensation magnetic field through the CAN FD bus. At the same time, data interaction between the controller and the computer is carried out through Ethernet to achieve functions such as system monitoring, configuration, and management; among them, the computer is set in the equipment room, and the equipment room is outside the shielding housing.

[0041] 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 being processed by the controller through calculations, it precisely controls the electromagnetic compensation coil to generate a compensation magnetic field through the CAN FD bus. At the same time, data interaction between the controller and the computer is carried out through Ethernet.

[0042] The structure and arrangement of the electromagnetic compensation coil refer to Figures 5-7 where Figure 5 is a single-axis coil; Figure 6The black color represents the room frame, the blue color represents the X-axis slot, the red color represents the Y-axis slot, the yellow color represents the Z-axis slot, and the green color represents the connection slot between the room and the external room; Figure 7 The blue color represents the X-axis slot, the red color represents the Y-axis slot, and the yellow color represents the Z-axis slot. Uniaxial coils are arranged in the X-axis slot, Y-axis slot, and Z-axis slot. The coil density can be spaced 1m 3 、0.5m 3 、0.2m 3 etc., and the number of turns can be 50 - 150 turns.

[0043] In step S2.2, 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 region in real time, and deduce the current values required for each coil, including: S2.2.1. Initialize parameters and determine the linear relationship matrix between the coil and the magnetic field through experiments and simulations; Let the magnetic field sensitivity of the current of the j-th electromagnetic compensation coil to the i-th high-precision magnetic sensor be gij, the number of high-precision magnetic sensors be M, the number of electromagnetic compensation coils be N, and the M×N-dimensional matrix be G, where N≥M; Then the coupling matrix formula is: ; Among them, ; g11 refers to the sensitivity of the first coil to the first sensor; gij represents the corresponding change in the magnetic field at sensor i when the current of coil j changes by 1A, that is, the magnetic field sensitivity of the current of the j-th electromagnetic compensation coil to the i-th magnetic field measurement point; represents the change in the magnetic field at the i-th magnetic field measurement point; represents the change in the current of the j-th coil; By setting the coupling matrix, the mutual inductance interference between the electromagnetic compensation coils can be eliminated, the compensation accuracy can be improved, the linear influence of each coil on the magnetic field can be quantified, providing input for the control algorithm, ensuring that subsequent predictions and optimizations are based on real data, and the cross-interference between multiple coils can be eliminated through matrix pseudo-inversion, improving the compensation accuracy, especially suitable for solving the problem that in high-interference regions, the distance between electromagnetic compensation coils is relatively close, increasing the possibility of interference.

[0044] S2.2.2. Build a prediction model, generate multi-step magnetic field prediction values based on the current and interference prediction, and predict the magnetic field distribution at the next moment; Let the magnetic field prediction vector at the (k + 1)-th moment be B(k + 1), the coil current vector at the k-th moment be I(k), and the predicted value of the dynamic interference field strength at the k-th moment be d(k), ; By planning the current adjustment strategy in advance, the response delay can be reduced, and the unmodeled environmental noise can be canceled out by the predicted value of the dynamic interference field strength.

[0045] In this embodiment, as another alternative implementation, automatically generating a compensation magnetic field further includes: storing in the memory of the computer the test device types and interference parameters with a mapping relationship in a structured manner; when receiving the input test device type to be tested, calling the target interference parameter corresponding to the test device type to be tested according to the mapping relationship.

[0046] By storing in a structured manner the test device types and interference parameters with a mapping relationship, it is possible to determine the corresponding target interference parameter according to the type of the device to be tested; considering the correlation with magnetic field compensation from the perspective of the device type, and thus the compensation magnetic field can also be automatically generated based on this parameter.

[0047] In some embodiments, the test device type can also be used as a factor affecting magnetic field compensation and combined with the prediction by the prediction model to further improve the accuracy of magnetic field compensation.

[0048] S2.2.3. Optimize the prediction model to balance the magnetic field accuracy and energy consumption; Let the target magnetic field vector be Btarget, usually a zero field; the current change at the k + jth moment is ; the energy consumption penalty coefficient is λ; the prediction horizon is Hp, and the control horizon is Hc; Then: If λ = 0.1, it means the system pays more attention to the magnetic field accuracy and allows larger current fluctuations; if λ = 0.5, it means the system pays more attention to energy conservation and suppresses current mutations. The prediction horizon Hp represents how many time steps in the future the controller predicts the system state at each step. For example, if Hp = 10, it means predicting the magnetic field change in the next 10 ms to predict the trend of magnetic field interference in advance and optimize the compensation strategy of the electromagnetic compensation coil; the control horizon Hc represents how many time steps in the future the controller optimizes the control input at each step. For example, if Hc = 5, then optimize the current adjustment strategy for 5 steps (corresponding to the next 5 ms). By limiting the number of optimization variables, the real-time calculation load is reduced. For the control output after Hc, the last optimized value is defaulted, for example, I5 = I6 =... = I 10 ; within each control cycle, based on the current magnetic field data and interference prediction, generate the optimal current command to quickly cancel the instantaneous interference, quickly respond to the instantaneous interference, and ensure real-time performance; by minimizing the magnetic field error to ensure that the residual magnetic field meets the requirements (i.e., less than 20 nT), and by penalizing the current change , it is possible to reduce power consumption and heat load, balance magnetic field accuracy and energy consumption by setting an energy consumption penalty coefficient in the objective function, etc., achieve dynamic weight adjustment, thereby reaching the global optimal solution and avoiding falling into the local optimal trap.

[0049] Preferably, Hc ≤ Hp; when Hc = Hp, optimize the control inputs of all prediction steps, with the largest computational amount but the highest accuracy; when Hc < Hp, sacrifice some accuracy to improve real-time performance.

[0050] S2.2.4. Set the reward function r(k) to quantify the quality of control actions, guide the update of the reinforcement learning strategy, dynamically adjust the control strategy through reinforcement learning, optimize the long-term cumulative performance, and optimize the global performance; Let the magnetic field error weight coefficient be α and the current change weight coefficient be β; among them, α represents the magnetic field error weight coefficient, emphasizing the compensation accuracy; β represents the energy consumption change weight coefficient, suppressing current mutations; α + β = 1, generally taking α = 0.7 and β = 0.3, giving priority to ensuring the magnetic field accuracy; ; Among them, ; Preferably, determine the error magnitude and dynamically adjust α, ; Among them, ; Dynamically adjusting the weights of α and β according to the real-time error can achieve adaptive optimization, and when the magnetic field changes due to the aging of the learning device or the drift law of the environment, the compensation performance can still be continuously maintained, which is beneficial to long-term stability compensation.

[0051] The linear relationship matrix between the coil and the magnetic field determined through experiments and simulations provides a solid physical basis for the prediction model and the optimization process, ensures the reliability of the input data, and effectively avoids the accumulation of errors in subsequent calculations; based on this matrix, the prediction model combines the current current and interference to predict and generate multi-step magnetic field prediction values, realizing forward-looking control and reducing response delay; at the same time, the prediction model and the reward function cooperate with each other, and through long-term learning, continuously cover various possible interference patterns within the entire time domain; the reward function dynamically adjusts the weights according to the real-time error and the system working conditions through long-term strategy optimization, guiding the system to make adaptive decisions in a complex and changing environment and effectively coping with various complex environmental changes; through the close cooperation of the above parts, the system has successfully achieved an effective combination of accuracy, real-time performance, energy efficiency, and self-adaptability, and can operate stably in the electron microscope room scenario.

[0052] S3. Set a shielding door on the wall inside the shielding enclosure; The composite shielding door is selected with a 14-mm-thick Q235 low-carbon steel support, which has the functions of magnetic shielding, electromagnetic shielding, and ray protection; the magnetic permeability of the low-carbon steel is preferably 4000.

[0053] The composite shielding door includes: a door frame 1 installed on the shielding housing, a left door leaf 2 and a right door leaf 3 oppositely installed 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 arranged on the left door leaf 2, and an upper and lower linkage door leaf bolt 8 is arranged on the right door leaf to fix the right door leaf 3 to the door frame 1. A copper elastic reed 6 is also installed on the periphery of the door frame 1, and the copper elastic reed 6 can ensure reliable electrical contact between the door frame 1 and the door leaf, ensuring a good shielding effect.

[0054] As can be seen from the above description, in the embodiment of the present application, a method of constructing an environmental magnetic field model and setting electromagnetic compensation coils in the environmental magnetic field model to automatically generate compensation magnetic fields in three orthogonal directions of X, Y, and Z respectively is adopted. Through the shielding housing; the electromagnetic compensation coils arranged inside the shielding housing; the electromagnetic compensation coils are electrically connected to a magnetic field compensation controller, and the magnetic field compensation controller is respectively 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 regulate 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 automatic generation of the compensation magnetic field includes: initializing parameters, determining the linear relationship matrix between the coil and the magnetic field through experiments and simulations; constructing a prediction model, the prediction model is based on the current current and interference prediction, generating multi-step magnetic field prediction values, predicting the magnetic field distribution at the next moment; optimizing the prediction model; setting a reward function; achieving the purpose of actively compensating the magnetic field, thus realizing the technical effect that the compensation magnetic field can be adaptively generated according to the field strength in the electron microscope room, and further solving the technical problem that it is difficult to determine effective electromagnetic interference elimination because high-precision magnetoelectric experiments not only need to shield the electromagnetic interference generated by equipment in adjacent rooms, but also need to eliminate the electromagnetic interference field strength generated by the auxiliary equipment of the experimental equipment, and in actual situations, the specific performance parameters of the electromagnetic equipment are often unknown.

[0055] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for magnetic shielding in an electron microscope room, characterized in that, Perform magnetic shielding using the magnetic shielding device for the electron microscope room; The magnetic shielding device for the electron microscope room includes: A shielding housing; An electromagnetic compensation coil disposed inside the shielding housing; The electromagnetic compensation coil is electrically connected to a magnetic field compensation controller, and the magnetic field compensation controller is electrically connected to a high-precision magnetic sensor and a computer respectively; 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 regulate 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 automatic generation of the compensation magnetic field includes: Initializing parameters and 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 and interference predictions and predicts the magnetic field distribution at the next moment; Optimizing the prediction model; Setting a reward function.

2. The method for magnetic shielding of an electron microscope room according to claim 1, wherein Constructing the linear relationship matrix includes: Let the magnetic field sensitivity of the current of the jth electromagnetic compensation coil to the ith high-precision magnetic sensor be gij, the number of high-precision magnetic sensors be M, the number of electromagnetic compensation coils be N, and the M×N-dimensional matrix be G, where N≥M; Then the coupling matrix is: Among them, .

3. The method for magnetic shielding of an electron microscope room according to claim 1, wherein The construction of the prediction model includes: Let the magnetic field prediction vector at the k + 1 moment be B(k + 1), the coil current vector at the k moment be I(k), and the predicted value of the dynamic interference field strength at the k moment be d(k), 。 4. The method for magnetic shielding of an electron microscope room according to claim 1, wherein Optimizing the prediction model includes: setting the target magnetic field vector as Btarget, usually a zero field; the current change at the k + jth moment is ; the energy consumption penalty coefficient is λ; the prediction time domain is Hp, and the control time domain is Hc; Then: ； The setting of the reward function includes: Let the magnetic field error weight coefficient be α and the current change weight coefficient be β; where α represents the magnetic field error weight coefficient, emphasizing the compensation accuracy; β represents the energy consumption change weight coefficient, suppressing current mutation; α + β = 1, generally taking α = 0.7 and β = 0.3, giving priority to ensuring the magnetic field accuracy; ； Among them, ; Preferably, determine the error size and dynamically adjust α, ； Among them, ; Dynamically adjusting the weights of α and β according to the real-time error can achieve adaptive optimization.

5. The method for magnetic shielding of an electron microscope room according to claim 1, wherein The automatic generation of the compensation magnetic field further includes: Test device types and interference parameters with a mapping relationship are structurally stored in the memory of the computer; When the input test device type is received, the target interference parameters corresponding to the test device type are called according to the mapping relationship.

6. The method for magnetic shielding of an electron microscope room according to claim 1, wherein, A composite shielding door for magnetic field and electric field shielding is provided on the wall inside the shielding housing; The composite shielding door includes: A door frame installed on the shielding housing, a left door leaf and a right door leaf oppositely installed on the door frame; An internal tightening component is provided on the left door leaf, and a door leaf bolt is provided on the right door leaf.

7. The method for magnetic shielding of an electron microscope room according to claim 6, characterized in that, Copper elastic reed pieces are also installed on the periphery of the door frame.

8. A computer-readable storage medium, characterized in that, A computer program is stored in the computer-readable storage medium, wherein the computer program is set to execute the magnetic shielding method for the electron microscope room according to any one of claims 1 to 5 when running.

9. An electronic device, comprising: A memory and a processor, characterized in that a computer program is stored in the memory, wherein the processor is set to run the computer program to execute the magnetic shielding method for the electron microscope room according to any one of claims 1 to 5.

Images