148 results about "Magnetic field shielding" patented technology

The invention provides a cement-based material residual magnetism intensity detection device, a detection method and an evaluation method. The cement-based material residual magnetism intensity detection device comprises a magnetic shielding cylinder, a fluxgate magnetometer and a test tool, the magnetic shielding cylinder is used for shielding a magnetic field to ensure stable test environment magnetic field; the fluxgate magnetometer comprises a fluxgate probe and a fluxgate digital display meter, the fluxgate probe is used for measuring a vector value of space magnetic induction intensity at a position corresponding to the fluxgate probe, and the fluxgate digital display meter is used for displaying a residual magnetism intensity measured value measured by the fluxgate probe; the test tool is arranged in the magnetic shielding cylinder and is used for placing a sample to be tested and fixing a fluxgate probe; according to the invention, a fluxgate magnetometer and a magnetic shielding cylinder are adopted to detect the residual magnetism intensity of the cement-based material, a standardized detection process and a test method are provided for solid components, a liquid mixture and a molded test block, and quantitative characterization of the distribution rule of the residual magnetism intensity of the cement-based material is realized through fewer detection points.

An electromagnetic wave- and magnetic field-absorbing-and-shielding sheet according to an exemplary embodiment of the present invention is implemented by comprising: an electromagnetic wave- and magnetic field-absorbing-and-shielding unit having a plurality of magnetic layers stacked to shield electromagnetic waves and magnetic fields; and an electromagnetic wave-absorbing adhesive member, which is arranged between the adjacent magnetic layers to absorb electromagnetic waves that have transmitted the magnetic layers or are reflected from the magnetic layers, and fixes the adjacent magnetic layers. Accordingly, together with an electromagnetic wave- and magnetic field-shielding function, the present invention has a function of enabling most of the electromagnetic waves reflected during shielding to be absorbed to minimize influence on surrounding electronic components, electronic devices, or a user of the electronic devices, caused by electromagnetic waves reflected during shielding and the magnetic field shielding, and thus can be widely applied to various electronic devices and the like.

An electromagnetic shielding and heat-conducting multi-layer material and a preparation method thereof. The multi-layer material includes an electric field shielding layer, an epoxy heat-conducting adhesive layer, and a magnetic field shielding layer. The electric field shielding layer includes a copper foil layer with a thickness of 5-12 μm. The magnetic field shielding layer has a thickness of 1-3 mm and includes a resin matrix A and carbon fiber cloth. By weight, the resin matrix A includes: 100 parts of bismaleimide resin, 60-68 parts of 3,3-diallylbisphenol A, 32-40 parts of triallyl isocyanurate, 18-20 parts of N,N-dimethylformamide, 100-160 parts of magnetic field shielding filler, 8-10 parts of di-sec-octyl phthalate, and 0.3-0.8 parts of cobalt naphthenate. The magnetic field shielding filler is compounded by nano-manganese zinc ferrite and micron nickel powder in a mass ratio of (80-120):(30-40). The electromagnetic shielding and heat-conducting multi-layer material of the present invention has both electric field and magnetic field shielding functions and is particularly suitable for high magnetic field and high electric field application environments.

The invention discloses a Helmholtz coil material lightning magnetic field shielding performance measuring device, which comprises a magnetic field generation device, a shielding test box is arranged in a magnetic field coverage range of the magnetic field generation device, an open hole is formed in the shielding test box, and the open hole enables a magnetic line of force of the magnetic field generation device to transversely penetrate through the shielding test box. The shielding test box is internally provided with the signal measurement unit, the signal measurement unit measures the magnetic field in the shielding test box, the lightning stroke magnetic field environment is accurately simulated, and the repeatability and accuracy of the shielding performance test are improved. The invention further discloses a method for measuring the lightning magnetic field shielding performance of the Helmholtz coil material, the lightning magnetic field shielding performance of the measured shielding material is measured by applying the device for measuring the lightning magnetic field shielding performance of the Helmholtz coil material, and the problem that traditional measurement is poor in accuracy is effectively solved.

The invention belongs to the technical field of magnetic field shielding, and discloses an electromagnetic wave absorbing material and device. The electromagnetic wave absorbing material provided by the invention comprises a first skin glass fiber reinforced plastic, a core layer medium, an impedance metamaterial, a second skin glass fiber reinforced plastic and a reflecting layer which are sequentially arranged from top to bottom, the impedance metamaterial comprises a dielectric film and two hollowed-out surface impedance metamaterial layers with different periodic structures, wherein the two hollowed-out surface impedance metamaterial layers are located on the front face and the back face of the dielectric film. The electromagnetic wave absorbing device provided by the invention comprises the electromagnetic wave absorbing material. The high-strength wave-absorbing material has high structural strength and also has relatively good wave-absorbing performance.

The application discloses a kind of armored double-layer shielded dry reed relay and its manufacturing method.The dry reed relay includes dry reed tube, inner shield tube, coil framework, coil, outer shield shell, coil lead, shield lead, side plate, sealing assembly and switch lead.The armored double-layer shielded structure of the above-mentioned dry reed relay can solve the problem of dry reed tube contact characteristic impedance matching uniformity by means of inner layer shielding, solve the problem of relay coil magnetic field leakage and low-frequency electromagnetic field shielding by means of outer layer shielding, and realize the problem of relay structure complete shielding and distributed parameter uniformity by means of coaxial structure.

Provided is a magnetic field shielding module for an electric vehicle. The magnetic field shielding module for an electric vehicle according to an embodiment of the present invention is utilized in a wireless power transmission module for an electric vehicle, and comprises: a shielding layer including a plurality of unit blocks which are made of ferrite materials so as to be able to block a magnetic field generated from a flat coil in which a conductive member is wound multiple times; and a coil accommodation groove recessed to a certain depth from one surface of the shielding layer so as to be able to accommodate the thickness of the flat coil. The shielding layer is formed in a plate shape having a certain area by arranging the plurality of unit blocks adjacent to each other.

According to various embodiments of the present disclosure, an electronic device may include: a display; a coil; a magnet assembly including a plurality of first magnets disposed to surround the coil and a plurality of second magnets disposed to surround the plurality of first magnets at positions spaced apart from the plurality of first magnets by a predetermined distance; a first magnetic field shielding sheet extending along the magnet assembly in a direction toward the display and attached to the magnet assembly; a second magnetic field shielding sheet disposed between the coil and the display in a direction from the first magnetic field shielding sheet toward the display; and a third magnetic field shielding sheet disposed between the display and the second magnetic field shielding sheet. Various embodiments may be possible in addition to the various embodiments disclosed in this document.

1. The name of this design product: Thermocouple (K-type thermocouple with magnetic field shielding function). 2. Purpose of this design product: Used in electromagnetic induction heating conditions. To address the defects of thermocouples, such as being easily heated by induction and disturbed by magnetic fields, a thermocouple with magnetic field shielding function was developed. 3. The key point of the design of this product lies in its shape. 4. The picture or photo that best illustrates the design points: three-dimensional picture.

This utility model discloses a modular stacked electrical component, belonging to the field of electrical component technology. It includes a housing, a perforated fixing strip welded to the inner surface of the housing, a side support strip on the upper surface of the perforated fixing strip, an internal hexagon screw on the inner surface of the side support strip, a movably latching plate on the outer surface of the internal hexagon screw, a magnetic field shielding mesh fixedly connected to the outer surface of the latching plate, a deformable rubber fixedly connected to the outer surface of the magnetic field shielding mesh, and a fixing block fixedly connected to the outer surface of the deformable rubber away from the latching plate. One side of the electrical component is supported by the perforated fixing strip and connected to the side support strip via the internal hexagon screw, completing the bottom support. The protruding end of the internal hexagon screw is fixed by the latching plate. The deformable rubber, through deformation and bending, correspondingly drives the magnetic field shielding mesh support. The magnetic field shielding mesh wraps around the electrical equipment, completing electromagnetic shielding. The fixing block is fixed by being latched in an inclined groove and by deforming outwards to latch onto the inner surface of the inclined groove.

A device fixing seat that is convenient for disassembly and assembly, including a base. A first chamber, a second chamber, and a third chamber are provided on the base. A driving device is provided in the third chamber. A first actuating device, a first flexible magnetic field shielding cover, and a first magnet are provided in the first chamber. A second actuating device, a second flexible magnetic field shielding cover, and a second magnet are provided in the second chamber. The driving device can simultaneously drive the first actuating device and the second actuating device to stretch and compress the first flexible magnetic field shielding cover and the second flexible magnetic field shielding cover respectively, so as to surround or expose the first magnet and the second magnet, shield or expose the magnetic field of the magnets, thereby generating non-attraction or attraction to the steel plate below, and further facilitating the disassembly and installation of the fixing seat, which is convenient to use.

The application discloses a small animal independent ventilation non-magnetic cage feeding system for indoor air intake and exhaust in a sub-magnetic space, which comprises the following parts: an external magnetic field shielding room, a small animal feeding non-magnetic cage, a non-magnetic cage placing rack, a ventilation unit and an air purification unit and the like; the external magnetic field shielding room mainly shields the external geomagnetic field and provides a required sub-magnetic environment for small animal cultivation; the non-magnetic cage placing rack is mainly used for placing the small animal feeding non-magnetic cage and is equipped with independent ventilation pipelines required for small animal feeding and is also made of non-magnetic materials; the non-magnetic feeding system for small animal cultivation in the sub-magnetic space disclosed in the application is mainly used for in-depth research on the influence mechanism of the sub-magnetic field environment on living beings, so as to further improve the survival rate and life quality of astronauts in future space exploration and interstellar travel.

There is provided a performance testing and evaluation method for a permalloy material for construction of a magnetically-shielded room and relates to testing and evaluation on alloy shielding performance. The present disclosure aims to solve the problem of failure to satisfy the requirements of different application scenarios for the magnetic field shielding due to lack of in-depth research on the shielding effect of the current permalloy in the magnetically-shielded rooms. The method includes: at step 1, selecting a permalloy sample, and conducting quality inspection on the sample to ensure the sample is compliance with an experiment requirement; at step 2, setting up an experimental apparatus; where the permalloy sample is vertically placed, and a magnetic field generation coil and a magnetic field measuring sensor are respectively placed at left and right sides of the permalloy sample; at step 3, carrying out shielding performance testing and evaluation on the permalloy sample.

The invention discloses a double-excitation double-electrode electromagnetic flowmeter for high-frequency pulsating fluid measurement. The double-excitation double-electrode electromagnetic flowmeter comprises a pipe body structure and a control circuit. The pipe body structure comprises a lining and a guide pipe; the inner side face of the guide pipe is covered with a lining. A first group and a second group of electrodes are arranged in the conduit; a first group and a second group of coils are arranged at corresponding positions of the first group and the second group of electrodes in the inner cavity of the catheter; first and second magnetic field shielding covers sleeve the circumferential outer side of the conduit; the first and second groups of coils are respectively positioned inside the first and second magnetic field shielding covers; an annular grounding electrode is arranged between the first group of electrodes and the second group of electrodes; the annular grounding electrode is connected to the conduit through the grounding fastening electrode; the control circuit comprises a CPU module; the CPU module generates complementary periodic excitation waveforms to excite the coil, controls acquisition of electrode signals and is used for calculating flow data of fluid in the conduit. According to the invention, high-fidelity and continuous measurement of the flow of the high-frequency pulsating fluid can be realized, and the measurement precision is ensured.

To improve the accuracy of measuring the electric current flowing through a conductor. [Solution] A current measurement system comprising a magnetic field shield 3 configured to take in the magnetic field H generated by the current I flowing through the cable 9, a magnetic field sensor 4 installed inside the magnetic field shield 3, a predetermined sensor, and a current measuring device, wherein the predetermined sensor is a sensor for detecting the cable 9, the magnetic field sensor 4 detects the magnetic field H at the installation location, and the current measuring device acquires the detection result of the predetermined sensor and the detection result of the magnetic field sensor 4, identifies the center position of the cable 9 based on the acquired detection result of the predetermined sensor, and calculates the current value of the current I flowing through the cable 9 based on the identified center position and the acquired detection result of the magnetic field sensor 4.

The invention discloses a core orientator for paleomagnetism research, and belongs to the technical field of paleomagnetism core measurement. Comprising a hollow column, a magnetic field shielding assembly, an automatic leveling and inclination measuring assembly, an inclination angle measuring assembly, a sun compass and sun angle measuring assembly, a data acquisition and storage assembly, an automatic ink-jet marking assembly and a matched software system which work cooperatively. All the components are sequentially assembled in a layered mode, and an automatic closed loop of insertion, leveling, measurement, verification, recording, marking and transmission is formed. By adopting the core orientator for the paleomagnetic research, manual operation steps can be greatly reduced, personal errors and magnetic interference are avoided, the measurement precision and data consistency are improved, the core orientation working efficiency is remarkably improved, the measurement result is more reliable, sample correspondence is clear, and later informatization management is convenient to trace.

A magnetic resonance-compatible programmable synchronized photostimulation system includes a main control unit and a stimulation execution unit. The main control unit is located outside the magnetic resonance scanning room, while the stimulation execution unit is located inside the scanning room and consists only of an LED light panel shielded by a magnetic field. The main control unit is configured to: receive photostimulation sequence parameters configured by the user in a modular manner through a graphical interface; receive a scan trigger signal from the magnetic resonance equipment, and automatically control the start and stop of the photostimulation sequence based on the trigger signal using hardware triggering; thereby achieving high-precision time synchronization between photostimulation and magnetic resonance scanning while maintaining magnetic resonance compatibility. This invention solves electromagnetic compatibility issues through a split architecture, achieves millisecond-level synchronization accuracy through hardware TTL triggering, and enhances experimental paradigm flexibility through modular programmable sequences, making it suitable for neuroscience research fields such as functional magnetic resonance imaging.

This invention discloses a method for fabricating a non-magnetic spatial reticulated shell structure composed of carbon fiber sheets. The load-bearing components of this reticulated shell structure are made of non-magnetic carbon fiber, while the connecting nodes are made of non-magnetic titanium alloy. A magnetic shielding layer is arranged in the roof system above the structural layer, creating a non-magnetic space with a magnetic field strength below 1 nT inside the reticulated shell. Specifically, the load-bearing components are made of carbon fiber sheets, fixed by two carbon fiber limb plates in an interlimb connection to form a hollow rectangular composite section. The connecting nodes consist of titanium alloy node plates, titanium alloy bolt groups, and carbon fiber limb plates. The magnetic shielding layer of the roof system consists of a shielding layer pad, a shielding layer, a shielding layer pressure plate, a buffer layer, a permalloy plate, and pressure strips. This invention features lightweight, high strength, and non-magnetic properties, creating a near-zero residual magnetism space through the roof magnetic shielding layer. It can be applied to various functional buildings with high magnetic field shielding requirements, as well as to general construction engineering.

The application discloses a kind of magnetic field shielding method and device of mechanical pump electron beam welding, based on the simulation analysis of the magnetic field distribution at the weld of mechanical pump, according to the shape of mechanical pump, iterative design magnetic field shielding device, adopt high permeability permalloy to make " two half splicing " type double shielding structure, the splicing seam of inside and outside two shielding layers is 90 ° angle, installed in the periphery of mechanical pump, in the premise of not changing the performance of mechanical pump itself, not transforming electron beam welding equipment realizes beam current no deflection in the process of mechanical pump electron beam welding, realizes the precision welding of mechanical pump.

The utility model discloses an inductance insulation framework, which relates to the technical field of inductance frameworks and comprises an inductance framework, two groups of isolation parts and a pressing part, the two groups of isolation parts are symmetrically distributed on two sides of the inductance framework, each isolation part comprises a shielding wing plate made of aluminum, and the pressing part comprises a pressing plate made of aluminum. Two sliding blocks are arranged on the inner side face of the shielding wing plate in an up-down symmetrical elastic sliding mode, and two splayed push-pull rods are hinged to the face, away from the inductance framework, of the pressing plate. According to the utility model, through the arrangement of the isolation part, after the coil is wound from the outside of the inductor framework, the iron core is inserted from the inside of the inductor framework and the assembly of the non-shielding inductor is completed, the shielding wing plates are respectively clamped at the two sides of the inductor framework, so that the electromagnetic shielding characteristic of aluminum materials is utilized, and when a plurality of groups of non-shielding inductors are distributed and mounted on a circuit board, the shielding wing plates are clamped at the two sides of the inductor framework; the two groups of shielding wing plates made of aluminum materials are matched with each other, so that magnetic field shielding can be effectively carried out on the inductors from two sides, and mutual inductance interference between two adjacent inductors is avoided.

The invention discloses a magnetic shielding assembly and a magnetic shielding system, and relates to the technical field of magnetic shielding, the magnetic shielding assembly comprises a magnetic shielding carrier, and the bottom of the magnetic shielding carrier supports a movable wheel; the magnetic shielding cover shell is movably arranged above the magnetic shielding carrier, and a shielding space is formed in the magnetic shielding cover shell; and the shielding coil structure is arranged in the shielding space and can move relative to the magnetic shielding cover shell. According to the magnetic shielding assembly, different magnetic field environments can be shielded, shielding optimization of the different magnetic field environments is achieved, the optimal magnetic field shielding effect is achieved, the working efficiency is greatly improved, operation is convenient, and damage to the human body is reduced.

The present invention addresses the problem of providing an electromagnetic wave shielding composition which has electromagnetic wave shielding performance and is capable of suppressing an increase in fluidity when heated. The above-mentioned problem is solved by an electromagnetic wave-shielding composition comprising at least one component (A) selected from the group consisting of thermoplastic resins and thermoplastic elastomers and a soft magnetic powder (B) at a mass ratio (component (A) / component (B)) in the range of 5 / 95 to 95 / 5, the composition further contains 0.02-1.4 parts by mass of component (C), which is at least one compound selected from among phosphite ester compounds and phosphate ester compounds, per 100 parts by mass of the total of the component (A) and the component (B), and a sheet having a thickness of 2.0 mm, which is obtained by molding the composition, exhibits a magnetic field shielding performance of 3 dB or more at both frequencies of 1 MHz and 10 MHz as measured by the KEC method.

A magnetic field shielding sheet is provided. A magnetic field shielding sheet according to an embodiment of the present invention comprises: a plate-shaped sheet body having a magnetic sheet containing a metal component so as to be capable of shielding a magnetic field generated by an antenna, and having a first surface and a second surface facing each other; a first protective sheet attached to a first surface of the sheet main body with an adhesive layer as a medium to prevent the first surface from being exposed to the outside; and a second protective sheet attached to a second surface of the sheet body with an adhesive layer as a medium to prevent the second surface from being exposed to the outside, wherein the first protective sheet and the second protective sheet are respectively made of a non-conductive material with a magnetic field shielding property, so that the sheet main body is protected from being influenced by an external environment, the shielding property of the sheet main body is supplemented, and the eddy current loss is reduced.

The utility model provides metal detection equipment with a magnetic field shielding device, which comprises a metal detection head, a first shielding case and a second shielding case, and is characterized in that the first shielding case is fixed at one end part of a detection window of the metal detection head and surrounds one end part area of the detection window; and the second shielding cover is fixed at the other end part of the detection window of the metal detection head and surrounds the area of the other end part of the detection window. The shielding covers are installed on the two sides of the magnetic field window of the metal detection head, the structure is simple, installation is convenient, and the anti-interference capability of the metal detection head of the metal detection and weighing all-in-one machine to an external magnetic field can be improved. According to the metal detection equipment, shielding of an external magnetic field can be realized only by installing the magnetic field shielding mechanical device on the metal detection and weighing all-in-one machine, and improvement of the anti-interference capability of the metal detection head is facilitated.

The invention relates to a magnetic field shielding structure and a transient electromagnetic detection device, and relates to the technical field of transient electromagnetic detection, the magnetic field shielding structure comprises a shielding member, the shielding member comprises a plurality of shielding structures, the plurality of shielding structures are arranged along the circumferential direction of the shielding member, each shielding structure comprises a shielding part and an isolation part, and in two adjacent shielding structures, the isolation part is arranged along the circumferential direction of the shielding member. The shielding part and the isolation part are arranged in a staggered manner, the isolation part is made of an insulating material, the magnetic field intensity radiated by the transmitting coil in non-detection directions such as the upward direction and the lateral direction can be effectively weakened through the arrangement of the shielding part, invalid interference signals can be reduced, and meanwhile, the shielding part and the insulating isolation part are arranged in a staggered manner, so that the shielding effect is improved. Therefore, generation of eddy current in the shielding part can be inhibited, superposition of an additional secondary magnetic field formed by the eddy current and an effective secondary magnetic field signal generated by the underground target body can be avoided, the accuracy of detection data can be greatly improved, and the problem of detection distortion caused by eddy current interference of an existing shielding structure is solved.

The utility model relates to the technical field of magnetic induction type keyboards, in particular to a magnetic suction foot support structure of a magnetic induction type keyboard, and aims to solve the problems that a traditional buckle foot support is not attractive and a traditional magnetic suction type foot pad can interfere with the magnetic induction type keyboard, the magnetic suction foot support structure comprises a bottom shell, and a circuit board is fixedly installed on the inner wall of the bottom shell. According to the magnetic induction keyboard, the first Halbach array magnet and the second Halbach array magnet are matched with each other, so that the magnetic field of the sides, close to each other, of the first Halbach array magnet and the second Halbach array magnet is increased, the magnetic field of the sides, away from each other, of the first Halbach array magnet and the second Halbach array magnet is greatly reduced, and interference on the magnetic induction keyboard is reduced; a magnetic field above the first Halbach array magnet can be collected and absorbed again through the magnetic field shielding alloy block, the first Halbach array magnet can be prevented from interfering with a magnetic induction element on the circuit board, the keyboard bottom shell can be taken down at any time, it is ensured that the integrity of the bottom of the keyboard bottom shell is not damaged, the attractiveness is improved, and the keyboard is convenient to use. And the method is suitable for a magnetic induction keyboard.

The application discloses a kind of rock core orienter for paleomagnetic research, belong to paleomagnetic rock core measurement technical field, including the hollow column of collaborative work, magnetic field shielding component, automatic leveling and inclination measurement component, inclination measurement component, sun compass and sun angle measurement component, data acquisition and storage component, automatic ink jet marking component and matching software system;Each component is sequentially layered assembly, forms the automation closed loop of "insertion-leveling-measurement-verification-recording-marking-transmission".The rock core orienter for paleomagnetic research described above is used in the application, can greatly reduce manual operation steps, avoid human error and magnetic interference, improve measurement accuracy and data consistency, realize that core orientation work efficiency is significantly improved, measurement result is more reliable, sample corresponding is clear and post information management is convenient traceability.

The utility model discloses a winding structure with a magnetic field shielding assembly, which comprises an annular body, the annular body is provided with a notch, the annular body is provided with a connecting piece, the annular body is made of an aluminum plate with the thickness of 2mm and is used for being installed at the lower end part of a transformer coil winding, and the annular body is grounded. The utility model has the beneficial effects that the leakage magnetic field of the transformer is effectively reduced, the leakage magnetic field generated in the transformer is effectively blocked and reflected, the interference of the leakage magnetic field to surrounding electrical equipment is reduced, and the performance and the stability of the transformer are improved; the influence of a leakage magnetic field and external electromagnetic waves is reduced, the fault risk of the transformer is reduced, and the safety and stability are improved; the process is simple, operation is easy, and installation cost and maintenance difficulty are reduced.

The invention belongs to the technical field of sensors, and discloses a non-contact current sensor with self-correction and high heat dissipation, which comprises an annular shell, a magnetic induction array, a unit self-correction mechanism, an efficient heat transfer structure, an intelligent heat dissipation system and a control module, if the magnetic field shielding heat conduction layer detects interference, the control module controls the micro push rod to realize geometric correction according to a feedback signal of the displacement sensor; and the intelligent heat dissipation system and the efficient heat transfer structure are adjusted according to signals of the temperature sensor, and the uniformity of the temperature field is kept. According to the sensor, synchronous adjustment of temperature and structural parameters is realized through a double closed-loop control mechanism, so that the sensor keeps high-precision work in high-temperature, vibration and electromagnetic interference environments; the phase change heat conduction material and the high heat conduction silica gel layer effectively buffer thermal stress and mechanical stress, prolong the service life of the device and reduce the maintenance frequency.

The utility model belongs to the technical field of high-end medical instruments, and discloses a particle accelerator and a particle beam therapy system. The particle accelerator includes a magnet and a shielding assembly. Wherein the magnet comprises a magnetic field part and a cold head which are connected with each other, and the magnetic field part can generate a magnetic field. The shielding assembly comprises an inner shielding piece, a middle shielding piece and an outer shielding piece, the inner shielding piece is provided with a closed cavity, a magnetic field part of the magnet is arranged in the closed cavity, the outer shielding piece is provided with a through groove penetrating through the outer shielding piece in the axis direction of the closed cavity, and the inner shielding piece and the middle shielding piece are both arranged in the through groove; the middle shielding piece is arranged between the outer peripheral surface of the inner shielding piece and the groove wall of the through groove; the inner shielding piece and the outer shielding piece are metal pieces capable of shielding a magnetic field, and the middle shielding piece is a non-metal piece capable of shielding the magnetic field. According to the utility model, the magnetic field generated by the magnet can be effectively shielded, the leakage of the magnetic field is avoided, and the reliability of a particle beam treatment system is guaranteed.