Method and device for testing gradient magnetic field of magnetic shielding barrel

Abstract

The invention provides a gradient magnetic field testing method and device for a magnetic shielding barrel. The gradient magnetic field testing device comprises a magnetic gradient testing unit, a supporting assembly and a connecting rod. An atom magnetometer can be nested in the magnetic gradient test unit to form a single magnetic field test unit. A plurality of magnetic gradient test units can be combined through the connecting rods to form a magnetic field gradient test array to adapt to the space in the shielding barrel. The magnetic field gradient test array can be connected with the supporting assembly, so that the magnetic field gradient test array is fixed in the shielding barrel and has mobility, and magnetic field distribution in the shielding barrel can be completely tested. According to the technical scheme, the technical problems that in the prior art, a visual large-range magnetic field imaging device is lacked, actual magnetic field gradient testing and compensation are lacked for a magnetic shielding barrel which is actually produced, processed and manufactured, and the space gradient in the magnetic shielding barrel can serve as an error term to be introduced into a magnetometer testing result are solved.

Description

Technical Field

[0001] This invention relates to the field of magnetic field shielding technology, and in particular to a method and apparatus for testing the gradient magnetic field of a magnetic shielding barrel. Background Technology

[0002] Magnetic fields are an important area of ​​study in physics, and various methods for measuring them have been developed. Among these, magnetic shielding barrels play a crucial role in establishing a standard magnetic field measurement environment. By shielding against external magnetic field interference, magnetic shielding barrels provide feasible conditions for designing and manufacturing various high-sensitivity magnetometers. However, due to limitations in current shielding barrel design and manufacturing processes, traditional permalloy shielding barrels contain an internal gradient on the order of nT, which poses a certain obstacle to the production and testing of high-sensitivity atomic magnetometers. Furthermore, most magnetic shielding barrels are currently non-standard customized products with varying internal dimensions. Designing dedicated magnetic field gradient testing devices for magnetic shielding barrels of different sizes and applications is a complex process, and there is an urgent need for a universal magnetic field gradient testing device for magnetic shielding barrels. Moreover, there is a lack of intuitive, large-scale magnetic field imaging devices. Research on the magnetic field distribution inside magnetic shielding barrels is mostly based on theoretical simulations and design, lacking practical magnetic field gradient testing and compensation for actually manufactured magnetic shielding barrels. The spatial gradient inside the magnetic shielding barrel will affect magnetometer testing. Summary of the Invention

[0003] This invention provides a method and apparatus for testing the gradient magnetic field of a magnetic shielding barrel, which can solve the technical problems of the lack of intuitive large-scale magnetic field imaging devices in the prior art, the lack of actual magnetic field gradient testing and compensation for magnetic shielding barrels in actual production and processing, and the fact that the spatial gradient inside the magnetic shielding barrel will affect the magnetometer test.

[0004] According to one aspect of the present invention, a method for testing the gradient magnetic field of a magnetic shielding barrel is provided. The method includes: selecting a suitable number of magnetic gradient testing units and connecting rods based on the target magnetic shielding barrel; installing magnetometers within each magnetic gradient testing unit; connecting multiple magnetic gradient testing units to each other via connecting rods to form a magnetometer testing array; installing support components around the magnetometer testing array and placing it within the target magnetic shielding barrel; the support components include a first support structure and a second support structure, the distance between the first support structure and the second support structure being adjustable; and adjusting the distance between the first support structure and the second support structure. The distance is adjusted so that the support assembly contacts the inner wall of the magnetic shielding barrel. The magnetometer test array is then placed inside the magnetic shielding barrel to test the magnetic field distribution in the axial cross-section of the magnetic shielding barrel. The internal space of the magnetic shielding barrel is marked at equal intervals along the axial direction. After the magnetic shielding barrel is closed, a physical rod or rope is used at the light-transmitting hole at the axial position of the magnetic shielding barrel to push or pull the entire array. The test process does not require reopening the magnetic shielding barrel, effectively avoiding the gradient magnetic field changes after the magnetic shielding barrel is subjected to stress. The axial magnetic field cross-sectional distribution at different positions in the axial space is recorded simultaneously to obtain the overall spatial magnetic field distribution inside the magnetic shielding barrel.

[0005] According to another aspect of the present invention, a magnetic shielding barrel gradient magnetic field testing device is provided, which is used to implement the magnetic shielding barrel gradient magnetic field testing method as described above.

[0006] Furthermore, the magnetic shielding barrel gradient magnetic field testing device includes multiple magnetic gradient testing units, multiple connecting rods, and multiple support components. The magnetic gradient testing units are used to fix the magnetometers, and the multiple magnetic gradient testing units are connected and fixed together by connecting rods to form a magnetometer testing array. The support components are used to support the magnetometer testing array and provide the magnetometer testing array with the ability to move within the magnetic shielding barrel.

[0007] Furthermore, the magnetic gradient testing unit has a magnetometer slot, a connecting slot, a support component fixing threaded hole, a first threaded hole, and a second threaded hole. The magnetometer slot is located at the center of the magnetic gradient testing unit, and various magnetometers can be nested inside the magnetometer slot. Multiple first threaded holes are provided around the magnetometer slot for installing set screws to fix the magnetometer. The connecting slot and the support component fixing threaded hole are located on different sides of the magnetic gradient testing unit. The connecting slot can install a connecting rod, and the side wall of the connecting slot has a second threaded hole for installing set screws to fix the connecting rod. The connecting rod can be placed in two magnetic gradient testing units simultaneously, fixing the two magnetic gradient testing units together. The support component fixing threaded hole can connect the magnetic gradient testing unit and the support component with screws.

[0008] Furthermore, the support assembly includes support structure one, support structure two, and movable rubber wheels. A fixing screw can be placed in the fixing hole on the upper part of support structure two to fix the support assembly to the threaded fixing hole of the magnetic gradient test unit. Support structure two contains a telescopic fixing groove, which can be fitted with a set screw to engage with the telescopic fixing threaded hole on support structure one. By adjusting the installation position of the set screw, the distance between support structure one and support structure two can be adjusted, thereby limiting the spatial position of the magnetic gradient test unit within the shielding barrel. Support structure one can be connected to the movable rubber wheels, providing conditions for the movement of the magnetic gradient test device to adapt to shielding barrels of different diameters, ensuring that the magnetic gradient test device is stably fitted inside the shielding barrel.

[0009] Furthermore, the magnetic gradient test unit, connecting rod, support components, and various screws within the device are all made of engineering plastics or rubber with a remanence level of less than 1 nT.

[0010] Furthermore, before testing and installation, the magnetic gradient test unit, connecting rod, support components, and various screws inside the device must all undergo residual magnetism testing using a fluxgate magnetometer to ensure that the residual magnetism level of each component of the device is less than 1nT and the interference level on the magnetic field gradient test results is less than 1nT.

[0011] Furthermore, the magnetic gradient test unit adopts a hollow, lightweight design.

[0012] This invention provides a method for testing the gradient magnetic field of a magnetically shielded barrel. This method flexibly combines multiple magnetic gradient testing units to adapt to shielding barrels of different sizes and specifications, testing the magnetic field gradient distribution within the barrel. Furthermore, a single test does not require multiple opening and closing of the barrel lid, reducing errors caused by gradient changes within the barrel due to pressure on the lid. In addition, this method can construct a large-scale magnetometer array, enabling testing of a wide area inside the shielding barrel, providing magnetic field testing capabilities beyond the uniform area of ​​the magnetically shielded barrel. This makes it possible to provide large-scale gradient compensation for magnetically shielded barrels and expand the uniform area within the barrel space. Attached Figure Description

[0013] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0014] Figure 1 This diagram illustrates the structure of the magnetic shielding barrel gradient magnetic field testing device installed inside the magnetic shielding barrel according to a specific embodiment of the present invention.

[0015] Figure 2 A schematic diagram of the structure of a magnetic shielding barrel gradient magnetic field testing device according to a specific embodiment of the present invention is shown;

[0016] Figure 3 A partial structural schematic diagram of the magnetic shielding barrel gradient magnetic field testing device provided according to a specific embodiment of the present invention is shown;

[0017] Figure 4 A schematic diagram of the structure of a magnetic gradient testing unit provided according to a specific embodiment of the present invention is shown;

[0018] Figure 5 A schematic diagram of the structure of a connecting rod according to a specific embodiment of the present invention is shown;

[0019] Figure 6a A schematic diagram of the support structure two provided according to a specific embodiment of the present invention is shown;

[0020] Figure 6b A schematic diagram of a support structure according to a specific embodiment of the present invention is shown.

[0021] The above figures include the following reference numerals:

[0022] 10. Magnetic gradient testing unit; 11. Magnetometer slot; 12. Connecting slot; 13. Support component fixing threaded hole; 14. First threaded hole; 15. Second threaded hole; 20. Connecting rod; 30. Support component; 31. Support structure one; 31a. Telescopic fixing threaded hole; 32. Support structure two; 32a. Fixing hole; 32b. Telescopic fixing slot; 33. Moving rubber wheel. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0026] like Figure 1 As shown, a method for testing the gradient magnetic field of a magnetic shielding barrel is provided according to a specific embodiment of the present invention. The method includes: selecting a suitable number of magnetic gradient testing units 10 and connecting rods 20 according to the target magnetic shielding barrel; installing magnetometers in each magnetic gradient testing unit 10; connecting multiple magnetic gradient testing units 10 to each other via connecting rods 20 to form a magnetometer testing array; installing support components 30 around the magnetometer testing array and placing them in the target magnetic shielding barrel; the support components 30 include a first support structure 31 and a second support structure 32, the distance between the first support structure 31 and the second support structure 32 being adjustable; adjusting the distance between the first support structure 31 and the second support structure 32. The support assembly 30 is brought into contact with the inner wall of the magnetic shielding barrel. The magnetometer test array is then placed inside the magnetic shielding barrel to test the magnetic field distribution in the axial cross-section of the magnetic shielding barrel. The magnetic field data of the magnetometer at each position is recorded to obtain the magnetic field gradient test of this cross-section. The internal space of the magnetic shielding barrel is marked at equal intervals along the axial direction. After the magnetic shielding barrel is closed, a solid rod or rope is used at the light-transmitting hole at the axial position of the magnetic shielding barrel to push or pull the entire array. The test process does not require reopening the magnetic shielding barrel, effectively avoiding the gradient magnetic field change after the magnetic shielding barrel is subjected to stress. The axial magnetic field cross-sectional distribution at different positions in the axial space is recorded simultaneously to obtain the overall spatial magnetic field distribution inside the magnetic shielding barrel and determine the magnetic field gradient range.

[0027] This configuration provides a method for testing the gradient magnetic field of a magnetically shielded barrel. This method flexibly combines multiple magnetic gradient testing units to adapt to shielding barrels of different sizes and specifications, testing the magnetic field gradient distribution within the barrel. Furthermore, a single test does not require multiple opening and closing of the barrel lid, reducing errors caused by gradient changes within the barrel due to pressure on the lid. In addition, this method can construct a large-scale magnetometer array, enabling testing of a wide area inside the shielding barrel, providing magnetic field testing capabilities beyond the uniform area of ​​the magnetically shielded barrel. This makes it possible to provide large-scale gradient compensation for magnetically shielded barrels and expand the uniform area within the barrel space.

[0028] According to another aspect of the present invention, a magnetic shielding barrel gradient magnetic field testing device is provided, which is used to implement the magnetic shielding barrel gradient magnetic field testing method described above. The magnetic shielding barrel gradient magnetic field testing device includes multiple magnetic gradient testing units 10, multiple connecting rods 20, and multiple support components 30. The magnetic gradient testing units 10 are used to fix magnetometers, and the multiple magnetic gradient testing units 10 are connected and fixed together by the connecting rods 20 to form a magnetometer testing array. The support components 30 are used to support the magnetometer testing array and provide the magnetic field testing array with the ability to move within the magnetic shielding barrel space.

[0029] This configuration provides a magnetic gradient magnetic field testing device for magnetically shielded barrels. The device features a modular design, allowing for the formation of magnetic measurement arrays of various types and specifications. It is adaptable to various non-standard magnetically shielded barrels and can serve as a universal gradient testing device for magnetically shielded barrels. The magnetic gradient testing process eliminates the need for repeatedly opening the barrel lid, effectively avoiding errors caused by stress within the magnetically shielded barrel. This gradient testing device and method can form a complete magnetic testing array, covering the entire spatial range of the magnetically shielded barrel. This provides the possibility for spatial gradient compensation of the magnetically shielded barrel and expanding the uniform magnetic field area.

[0030] Furthermore, in this invention, the magnetic gradient testing unit 10 has a magnetometer slot 11, a connecting slot 12, a support component fixing threaded hole 13, a first threaded hole 14, and a second threaded hole 15. The magnetometer slot 11 is located at the center of the magnetic gradient testing unit 10, and various magnetometers can be nested inside the magnetometer slot 11. Multiple first threaded holes 14 are provided around the inside of the magnetometer slot 11, and the multiple first threaded holes 14 are used to install set screws to fix the magnetometer. The connecting slot 12 and the support component fixing threaded hole 13 are located on different sides of the magnetic gradient testing unit 10. The connecting slot 12 can be used to install a connecting rod 20, and the side wall of the connecting slot 12 is provided with a second threaded hole 15. The second threaded hole 15 can be used to install set screws to fix the connecting rod 20. The connecting rod 20 can be placed in two magnetic gradient testing units 10 at the same time, fixing the two magnetic gradient testing units 10 together. The support component fixing threaded hole 13 can connect the magnetic gradient testing unit 10 and the support component 30 with screws.

[0031] In this invention, the support assembly 30 includes a first support structure 31, a second support structure 32, and a movable rubber wheel 33. A fixing screw can be placed in the fixing hole 32a on the upper part of the second support structure 32 to fix the support assembly 30 to the support assembly fixing threaded hole 13 of the magnetic gradient test unit 10. The second support structure 32 contains a telescopic fixing groove 32b, which can be fitted with a set screw to cooperate with the telescopic fixing threaded hole 31a on the first support structure 31. By adjusting the installation position of the set screw, the distance between the first support structure 31 and the second support structure 32 can be adjusted, thereby limiting the spatial position of the magnetic gradient test unit 10 in the shielding barrel. The first support structure 31 can be connected to the movable rubber wheel 33 to provide conditions for the movement of the magnetic gradient test device to adapt to shielding barrels of different diameters and ensure that the magnetic field gradient test device is stably embedded inside the shielding barrel.

[0032] Furthermore, in this invention, the entire device is designed to be non-magnetic, thus avoiding interference from the testing device itself with the magnetic gradient test results. Specifically, the magnetic gradient test unit 10, connecting rod 20, support assembly 30, and various screws within the device are all made of engineering plastics or rubber with a remanence level of less than 1 nT.

[0033] In addition, before testing and installation, the magnetic gradient test unit 10, connecting rod 20, support component 30 and various screws in the device must be tested for residual magnetism using a fluxgate magnetometer to ensure that the residual magnetism level of each component of the device is less than 1nT and the interference level on the magnetic field gradient test results is less than 1nT.

[0034] To gain a further understanding of the present invention, the following description is provided in conjunction with... Figures 1 to 6b The present invention provides a detailed description of the magnetic shielding barrel gradient magnetic field testing device and method.

[0035] like Figures 1 to 6bAs shown, this invention provides a gradient magnetic field testing device and method for magnetically shielded barrels. The method comprises a magnetic gradient testing unit, a support assembly, and connecting rods. An atomic magnetometer can be nested within the magnetic gradient testing unit to form a single magnetic field testing unit. Multiple magnetic gradient testing units can be combined via connecting rods to form a magnetic field gradient testing array, adaptable to the space inside the shielding barrel. The magnetic field gradient testing array can be connected to the support assembly, fixing the array within the shielding barrel while maintaining mobility, enabling complete testing of the magnetic field distribution within the shielding barrel. Due to current shielding barrel design and manufacturing processes, traditional permalloy shielding barrels exhibit a gradient on the order of nT, posing a challenge for testing with high-sensitivity atomic magnetometers. Since there is currently a lack of intuitive, large-scale magnetic field imaging devices, this invention proposes a magnetic field gradient testing device based on a magnetometer array. This device can be flexibly combined to adapt to shielding barrels of different sizes and specifications, testing the magnetic field gradient distribution within the shielding barrel, thus addressing the current trend of non-standard customization of magnetically shielded barrels. Furthermore, this device eliminates the need for frequent opening of the shielding barrel lid during use and testing, avoiding unnecessary magnetic field errors caused by the installation of the shielding barrel lid.

[0036] In this embodiment, the present invention provides a gradient magnetic field testing device and method for magnetically shielded barrels, thereby improving the gradient magnetic field testing capability of magnetically shielded barrels under existing technical conditions. It can serve as a universal device for gradient magnetic field testing of various non-standard magnetically shielded barrels, avoiding the gradient magnetic field change error caused by opening and closing the barrel lid during gradient testing. It provides magnetic field testing capability beyond the uniform region of the magnetically shielded barrel, making it possible to expand the uniform region of the magnetically shielded barrel through subsequent magnetic field gradient compensation. The device and method consist of a magnetic field testing unit, a connecting rod, and a support assembly. The magnetic field testing unit is used to fix a miniaturized atomic magnetometer and cooperates with the connecting rod to connect and fix it to form a magnetometer testing array. The support assembly is used to support the magnetic field testing unit array, providing the magnetic field testing array with the ability to move within the magnetically shielded barrel.

[0037] Furthermore, all parts of the testing apparatus and method must undergo necessary demagnetization design. Specifically, the magnetic gradient testing unit, connecting rods, support components, and all screws within the apparatus are made of engineering plastics or rubber with a remanence level of less than 1 nT. Before testing and installation, all components of the apparatus must undergo remanence testing using a fluxgate magnetometer to ensure that the remanence level of each component is less than 1 nT, and that the interference level with the magnetic field gradient test results is less than 1 nT.

[0038] Furthermore, the magnetic gradient testing unit includes a magnetometer slot, a connecting slot, and a support component fixing threaded hole structure, enabling it to connect with adjacent magnetic gradient testing units, connecting rods, and support components. The magnetometer slot can house various miniaturized atomic magnetometers, and set screws can be installed around the slot to secure the magnetometer. The connecting slot can accommodate connecting rod components, and set screws can be installed in the side wall threaded holes to secure the connecting rods. Connecting rods can be placed in two magnetic gradient testing units simultaneously, fixing the two units together. The support component fixing threaded holes allow for screw connection between the magnetic gradient testing unit and the support component. The magnetic gradient testing unit houses nested magnetometers and can connect externally to adjacent magnetic gradient testing units, forming a magnetic gradient testing magnetometer array. Because the magnetic gradient testing units can be combined, the magnetic gradient testing device can be configured to suit different inner diameters of the magnetic shielding barrel.

[0039] Furthermore, the support assembly consists of support structure one, support structure two, and movable rubber wheels. A fixing screw can be placed in the fixing hole on the upper part of support component two to fix the support assembly to the threaded hole of the support component of the magnetic gradient testing unit. Support component two contains a telescopic fixing groove, which can be fitted with a set screw to mate with the telescopic fixing threaded hole on support structure one. By adjusting the installation position of the set screw, the distance between support component one and support component two can be adjusted, thereby limiting the spatial position of the magnetic gradient testing unit within the shielding barrel. Support structure one can be connected to the movable rubber wheels, providing conditions for the movement of the magnetic gradient testing device to adapt to shielding barrels of different diameters, ensuring that the magnetic gradient testing device is stably fitted inside the shielding barrel.

[0040] Furthermore, the method of using the magnetic shielding barrel gradient testing device is as follows: Before testing, select an appropriate number of magnetic gradient testing unit components and connecting rods according to the target magnetic shielding barrel, connect them together, and place various small magnetometers such as atomic magnetometers and fluxgate magnetometers inside the magnetic gradient testing unit. Then, install the necessary support components around the array and place it inside the shielding barrel. By adjusting the distance between support component one and support component two, the array is fixed inside the magnetic shielding barrel, realizing the magnetic field distribution test of the magnetic shielding barrel in the axial direction section. The magnetic field data of the magnetometer at each position is counted to obtain the magnetic field gradient test of this section. In addition, the internal space of the magnetic shielding barrel is marked at equal intervals along the axial direction. After the magnetic shielding barrel is closed, a solid rod or rope is used at the light-transmitting hole at the axial position of the magnetic shielding barrel to push or pull the entire array. The test process does not require reopening the magnetic shielding barrel, effectively avoiding the gradient magnetic field change after the magnetic shielding barrel is subjected to stress. The axial magnetic field profile distribution at different positions in the axial space is recorded simultaneously to obtain the overall spatial magnetic field distribution inside the magnetic shielding barrel and determine the magnetic field gradient range.

[0041] This invention provides a magnetic gradient magnetic field testing device and method for magnetically shielded barrels. The device features an overall non-magnetized design, avoiding interference from the testing device itself with the magnetic gradient test results. Its modular design allows for the formation of magnetic measurement arrays of various types and specifications, adapting to various non-standard magnetically shielded barrels and serving as a universal magnetic gradient testing device. The magnetic gradient test process eliminates the need for repeated opening of the barrel lid, effectively avoiding errors caused by stress on the magnetically shielded barrel. Furthermore, the magnetic gradient testing unit employs a hollow, lightweight design, minimizing the stress on the magnetically shielded barrel caused by the weight of the entire testing setup. This gradient testing device and method can form a complete magnetic testing array, covering the entire spatial range of the magnetically shielded barrel, providing the possibility for spatial gradient compensation and expanding the uniform magnetic field area of ​​the magnetically shielded barrel.

[0042] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0043] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for testing the gradient magnetic field of a magnetically shielded barrel, characterized in that, The method for testing the gradient magnetic field of the magnetic shielding barrel includes: Select an appropriate number of magnetic gradient test units (10) and connecting rods (20) according to the target magnetic shielding barrel, and place magnetometers in each of the magnetic gradient test units (10). Multiple magnetic gradient test units (10) are connected to each other through connecting rods (20) to form a magnetometer test array. A support assembly (30) is installed around the magnetometer test array and placed in the target magnetic shielding barrel. The support assembly (30) includes a support structure one (31) and a support structure two (32). The distance between the support structure one (31) and the support structure two (32) is adjustable. Adjust the distance between the first support structure (31) and the second support structure (32) so that the support assembly (30) comes into contact with the inner wall of the magnetic shielding barrel. Set the magnetometer test array inside the magnetic shielding barrel to realize the magnetic field distribution test of the magnetic shielding barrel in the axial direction section. Count the magnetic field data of the magnetometer at each position to obtain the magnetic field gradient test of the section. The internal space of the magnetic shielding barrel is marked at equal intervals along the axial direction. After the magnetic shielding barrel is closed, a solid rod or rope is used at the light-transmitting hole at the axial position of the magnetic shielding barrel to push or pull the entire array. The test process does not require the magnetic shielding barrel to be opened again, which effectively avoids the gradient magnetic field change after the magnetic shielding barrel is subjected to stress. The axial magnetic field profile distribution at different positions in the axial space is recorded simultaneously to obtain the overall spatial magnetic field distribution inside the magnetic shielding barrel and determine the magnetic field gradient range.

2. A magnetic shielding barrel gradient magnetic field testing device, characterized in that, The magnetic shielding barrel gradient magnetic field testing device is used to implement the magnetic shielding barrel gradient magnetic field testing method as described in claim 1.

3. The magnetic shielding barrel gradient magnetic field testing device according to claim 2, characterized in that, The magnetic shielding barrel gradient magnetic field testing device includes multiple magnetic gradient testing units (10), multiple connecting rods (20), and multiple support components (30). The magnetic gradient testing units (10) are used to fix the magnetometers. Multiple magnetic gradient testing units (10) are connected and fixed to each other through the connecting rods (20) to form a magnetometer testing array. The support components (30) are used to support the magnetometer testing array and provide the magnetometer testing array with the ability to move within the magnetic shielding barrel.

4. The magnetic shielding barrel gradient magnetic field testing device according to claim 3, characterized in that, The magnetic gradient testing unit (10) has a magnetometer slot (11), a connecting slot (12), a support component fixing threaded hole (13), a first threaded hole (14), and a second threaded hole (15). The magnetometer slot (11) is located at the center of the magnetic gradient testing unit (10). Various magnetometers can be nested in the magnetometer slot (11). Multiple first threaded holes (14) are arranged around the inside of the magnetometer slot (11). The multiple first threaded holes (14) are used to install set screws to fix the magnetometer. The connecting slot (12) and the support component are fixed. Threaded holes (13) are provided on different sides of the magnetic gradient test unit (10). The connecting groove (12) can be used to install the connecting rod (20). The side wall of the connecting groove (12) is provided with the second threaded hole (15). The second threaded hole (15) can be used to install a set screw to fix the connecting rod (20). The connecting rod (20) can be placed in two magnetic gradient test units (10) at the same time to fix the two magnetic gradient test units (10) together. The threaded hole (13) of the support component can be used to connect the magnetic gradient test unit (10) and the support component (30) with screws.

5. The magnetic shielding barrel gradient magnetic field testing device according to claim 4, characterized in that, The support assembly (30) includes a first support structure (31), a second support structure (32), and a movable rubber wheel (33). A fixing screw can be placed in the fixing hole (32a) above the second support structure (32) to fix the support assembly (30) to the support assembly fixing threaded hole (13) of the magnetic gradient test unit (10). The second support structure (32) contains a telescopic fixing groove (32b), which can be fitted with a set screw to cooperate with the telescopic fixing threaded hole (31a) on the first support structure (31). By adjusting the installation position of the set screw, the distance between the first support structure (31) and the second support structure (32) can be adjusted, thereby limiting the spatial position of the magnetic gradient test unit (10) in the shielding barrel. The first support structure (31) can be connected to the movable rubber wheel (33) to provide conditions for the movement of the magnetic gradient test device to adapt to shielding barrels of different diameters and ensure that the magnetic gradient test device is stably embedded inside the shielding barrel.

6. The magnetic shielding barrel gradient magnetic field testing device according to claim 5, characterized in that, The magnetic gradient testing unit (10), the connecting rod (20), the support assembly (30), and all screws in the device are made of engineering plastics or rubber with a remanence level of less than 1 nT.

7. The magnetic shielding barrel gradient magnetic field testing device according to claim 6, characterized in that, Before testing and installation, the magnetic gradient test unit (10), the connecting rod (20), the support component (30), and all kinds of screws in the device must be tested for residual magnetism using a fluxgate magnetometer to ensure that the residual magnetism level of each component of the device is less than 1nT and the interference level on the magnetic field gradient test results is less than 1nT.

8. The magnetic shielding barrel gradient magnetic field testing device according to claim 7, characterized in that, The magnetic gradient test unit (10) adopts a hollow and lightweight design.

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