A superconducting magnet system

Abstract

The present application relates to the technical field of neutron scattering experiment, in particular to a superconducting magnet system. The superconducting magnet system comprises a superconducting magnet and a guide field magnet; the superconducting magnet has a sample space and a neutron incidence hole for the neutron beam to enter the sample space, and the superconducting magnet generates a reverse magnetic field opposite to the direction of the magnetic field in the sample space outside the neutron incidence hole; the guide field magnet is arranged outside the neutron incidence hole and is used for generating a guide field, and the direction of the guide field is opposite to the direction of the reverse magnetic field generated by the superconducting magnet at this position, so as to offset the reverse magnetic field. In the superconducting magnet system, the guide field generated by the guide field magnet can offset the reverse magnetic field generated by the superconducting magnet on the motion path of the neutron beam, so as to improve the neutron polarization rate.

Description

Technical Field

[0001] This invention relates to the field of neutron scattering experimental technology, and more specifically to a superconducting magnet system. Background Technology

[0002] Neutron scattering is an important technique for studying the microscopic structure and dynamics of matter by utilizing the various physical properties of neutrons. Because neutrons possess both a magnetic moment and strong penetrating power, they are ideally suited for observing small samples enclosed in a strong magnetic field within a superconducting magnet. Providing a strong magnetic field environment for neutron-scattered samples using superconducting magnets has become very common.

[0003] Polarized neutron scattering is a technique that utilizes the interaction between neutron spin and the sample and magnetic field for measurement, and is an important component of neutron scattering technology. Specifically, it involves aligning the spin direction of a neutron beam using methods such as polarized supermirrors and helium-3 filters, and analyzing the spin-flipping and non-flipping scattering of polarized neutrons in the sample to infer the direction of the sample's internal magnetic moment. Currently, polarized neutron scattering technology has been successfully applied to magnetic, strongly correlated, nanomaterials, spintronic materials, polymers, and biological materials.

[0004] However, the 5T low-temperature superconducting magnet used in the sample environment module will generate a magnetic field opposite to the center point on the neutron motion path, which will seriously affect the polarizability of the neutron beam. Summary of the Invention

[0005] The main technical problem solved by this invention is the low polarization of neutron beams.

[0006] One embodiment provides a superconducting magnet system, comprising:

[0007] A superconducting magnet having a sample space and a neutron entrance aperture for allowing a neutron beam to flow into the sample space, wherein the superconducting magnet generates a reverse magnetic field outside the neutron entrance aperture that is opposite to the direction of the magnetic field inside the sample space.

[0008] A guiding field magnet is disposed outside the neutron entrance aperture to generate a guiding field. The direction of the guiding field is opposite to the direction of the reverse magnetic field generated by the superconducting magnet at the location of the guiding field, so as to counteract the reverse magnetic field generated by the superconducting magnet.

[0009] In some embodiments, two sets of guiding field magnets are provided, and the two sets of guiding field magnets are respectively located on both sides of the axis of the neutron entrance aperture and arranged facing each other. The magnetization direction of the two sets of guiding field magnets is the same, so as to form the guiding field between the two sets of guiding field magnets.

[0010] In some embodiments, each group of guiding field magnets includes a plurality of square permanent magnets, which are arranged sequentially along the axial direction of the neutron incident aperture.

[0011] In some embodiments, the distance between the guiding field magnet and the superconducting magnet can be adjusted.

[0012] In some embodiments, the superconducting magnet system further includes a fixed support, which includes a base, a guide mechanism, and an adjustment platform. The base is fixed in position relative to the superconducting magnet. The guide mechanism is disposed on the base and arranged along the axial direction of the neutron entrance aperture. The guide field magnet is disposed on the adjustment platform. The adjustment platform is disposed on the guide mechanism and can move along the guide mechanism to adjust the distance between the guide field magnet and the superconducting magnet.

[0013] In some embodiments, the adjustment platform includes a slide and two support arms fixed to the slide, the two support arms being used to set two sets of the guide field magnets respectively.

[0014] In some embodiments, the adjustment platform further includes a slider located on the side of the support arm away from the superconducting magnet and movable relative to the support arm along the axial direction of the neutron entrance aperture, wherein the guiding field magnet is fixed to the slider.

[0015] In some embodiments, the superconducting magnet system further includes a force measuring device disposed on the side of the support arm near the slider, for contacting the guide field magnet and collecting the force data of the guide field magnet.

[0016] In some embodiments, each of the arms is provided with two force measuring devices, which are symmetrically distributed on both sides of the guide field magnet.

[0017] In some embodiments, the fixed bracket further includes a screw lifting mechanism for driving the adjustment platform. The screw lifting mechanism includes a motor and a lead screw. The motor drives the lead screw to rotate, and the adjustment platform is threadedly connected to the lead screw.

[0018] According to the superconducting magnet system of the above embodiment, the guiding field magnet can generate a guiding field. The direction of the guiding field is opposite to the direction of the reverse magnetic field generated by the superconducting magnet at the location of the guiding field. This can cancel the reverse magnetic field generated by the superconducting magnet on the neutron beam path and improve the neutron polarization. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the magnetic field distribution during the operation of a superconducting magnet.

[0020] Figure 2This is a schematic diagram showing the position of the guide field magnet in the superconducting magnet system of this application;

[0021] Figure 3 This is a perspective view of the superconducting magnet system of this application;

[0022] Figure 4 This is a perspective view of the mounting bracket in the superconducting magnet system of this application;

[0023] Figure 5 for Figure 4 Front view of the fixed bracket in the middle;

[0024] Figure 6 for Figure 4 Side view of the fixed bracket.

[0025] Figure label:

[0026] 100. Superconducting magnet; 110. Sample space; 120. Neutron entrance aperture;

[0027] 200. Guiding field magnet;

[0028] 300. Fixed bracket; 310. Base; 320. Guide mechanism; 321. Guide rod; 322. Connecting plate; 330. Adjustment platform; 331. Slide table; 332. Support arm; 333. Slider; 334. Limiting component; 335. Clearance groove;

[0029] 340. Force measuring device;

[0030] 350. Screw lifting mechanism; 351. Motor; 352. Lead screw. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0032] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0033] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0034] like Figure 1 As shown, for the 5T cryogenic superconducting magnet system used in the sample environment module, the superconducting magnet 100 generates a strong magnetic field inside the sample space 110 during operation to apply a magnetic field environment to the sample. However, the superconducting magnet 100 generates a reverse magnetic field in the region outside the neutron entrance aperture 120, which is opposite to the magnetic field direction inside the sample space 110. This reverse magnetic field is located on the path of the neutron beam and will perturb the spin direction of the polarized neutrons, resulting in a decrease in neutron polarizability and affecting the measurement accuracy of the scattering experiment.

[0035] To address the aforementioned technical problems, one embodiment provides a superconducting magnet system suitable for the field of neutron scattering experimental technology.

[0036] like Figure 2 As shown, the superconducting magnet system includes a superconducting magnet 100 and a guiding field magnet 200. The superconducting magnet 100 has a sample space 110 and a neutron entrance aperture 120 for allowing a neutron beam to flow into the sample space 110. The sample space 110 is used to place the sample to be tested, and the neutron beam enters the sample space 110 along the neutron entrance aperture 120 and is scattered by the sample.

[0037] A guiding field magnet 200 is positioned outside the neutron entrance aperture 120 to generate a guiding field. The direction of the guiding field is opposite to the direction of the reverse magnetic field generated by the superconducting magnet 100 at the location of the guiding field, in order to cancel out the reverse magnetic field generated by the superconducting magnet 100. By setting the guiding field magnet 200, the reverse magnetic field on the beam path is pre-compensated before the neutron beam enters the sample space 110, so that the neutron beam maintains a high polarization when it reaches the sample region.

[0038] In some embodiments, such as Figure 2As shown, two sets of guiding field magnets 200 are provided, located on opposite sides of the axis of the neutron entrance aperture 120 and arranged facing each other. The magnetization directions of the two sets of guiding field magnets 200 are consistent, so as to form a guiding field between the two sets of guiding field magnets 200. Specifically, when the superconducting magnet 100 is in operation, it generates an upward magnetic field within the sample space 110, and generates a downward reverse magnetic field at a certain distance outside the neutron entrance aperture 120. The two sets of guiding field magnets 200 are arranged vertically at intervals, with the magnetic poles being NS and NS respectively from top to bottom, thereby forming an upward guiding field between the two sets of guiding field magnets 200. The direction of this guiding field cancels out the reverse magnetic field at this position.

[0039] Two sets of guiding field magnets 200 are positioned opposite each other, forming a uniform and directionally controllable guiding field along the neutron incident path. The magnetic field direction of the guiding field is opposite to the reverse magnetic field generated by the superconducting magnet 100 outside the neutron incident aperture 120, thereby achieving magnetic field cancellation and improving neutron polarizability.

[0040] Furthermore, each group of guiding field magnets 200 includes multiple square permanent magnets, which are arranged sequentially along the axial direction of the neutron entrance aperture 120. This sequential arrangement of square permanent magnets along the axial direction extends the effective area of ​​the guiding field, ensuring that the neutron beam is affected by the guiding field throughout its longer path. The number of square permanent magnets can be determined based on their size and the reverse magnetic field range of the superconducting magnet 100; for example, three or four square permanent magnets can be used in each group.

[0041] In some embodiments, such as Figures 3-6 As shown, the distance between the guiding field magnet 200 and the superconducting magnet 100 is adjustable. By adjusting the distance between the guiding field magnet 200 and the superconducting magnet 100, the guiding field magnet 200 can be set accordingly based on the range of the reverse magnetic field generated by the superconducting magnet 100, so that the guiding field generated by the guiding field magnet 200 can fully cancel the reverse magnetic field, thereby improving the neutron polarizability.

[0042] like Figure 4As shown, to achieve the aforementioned distance adjustment, the superconducting magnet system may further include a fixed support 300. The fixed support 300 includes a base 310, a guide mechanism 320, and an adjustment platform 330. The base 310 is fixed in position relative to the superconducting magnet 100. Specifically, the base 310 can be rigidly fixed to the mounting reference surface of the superconducting magnet 100 module using a screw assembly. The guide mechanism 320 is disposed on the base 310 and arranged along the axial direction of the neutron entrance aperture 120. The guide field magnet 200 is disposed on the adjustment platform 330, which is also disposed on the guide mechanism 320 and can move along the guide mechanism 320 to adjust the distance between the guide field magnet 200 and the superconducting magnet 100. By sliding the adjustment platform 330 on the guide mechanism 320, the position of the guide field magnet 200 in the axial direction of the neutron entrance aperture 120 can be changed, thereby precisely controlling the relative distance between the guide field magnet 200 and the superconducting magnet 100.

[0043] In some embodiments, such as Figures 4-6 As shown, the adjustment platform 330 includes a slide 331 and two support arms 332 fixed to the slide 331. The two support arms 332 are used to set two sets of guide field magnets 200. The slide 331, as the basic moving component, cooperates with the guide mechanism 320 to achieve axial movement. The two support arms 332 extend from the slide 331 towards the location of the neutron beam movement path and are symmetrically arranged, each used to support the two sets of guide field magnets 200. This double-arm structure facilitates the symmetrical layout of the guide field magnets 200, ensuring that the guide field is evenly distributed on both sides of the neutron entrance aperture 120 axis.

[0044] The adjustment platform 330 may also include a slider 333. The slider 333 is located on the side of the support arm 332 away from the superconducting magnet 100 and is axially movable relative to the support arm 332 along the neutron entrance aperture 120. The guiding field magnet 200 is fixed to the slider 333. The slider 333 can slide freely within a small range on the support arm 332. The slider 333 facilitates the measurement of the force exerted on the guiding field magnet 200 by the superconducting magnet 100. The assembly of the slider 333 and the support arm 332 can be achieved as follows: the slider 333 has an optical aperture, and the support arm 332 has a limiting member 334. The slider 333 is slidably assembled to the limiting member 334 through the optical aperture. One end of the limiting member 334 is fixedly connected to the support arm 332, and the other end is used to limit the slider 333, preventing it from detaching from the support arm 332. The limiting member 334 can be a screw or a pin, with a head diameter larger than the optical aperture diameter, thus serving a limiting function. Before the superconducting magnet 100 is in operation, the slider 333 can slide freely on the limiting member 334.

[0045] In some embodiments, such as Figures 4-6As shown, the superconducting magnet system also includes a force measuring device 340. The force measuring device 340 is located on the side of the support arm 332 near the slider 333, and is used to contact the guide field magnet 200 and collect the force data of the guide field magnet 200. Because the superconducting magnet 100 generates a strong magnetic field during operation, the guide field magnet 200 will be subjected to a large magnetic force in this magnetic field. This force may cause the guide field magnet 200 to shift or indirectly act on the support arm 332, causing deformation of the fixed bracket 300.

[0046] By installing a force measuring device 340 on the support arm 332, the magnitude of the magnetic force on the guide field magnet 200 can be monitored in real time, thereby determining the structural safety of the fixed support 300. When the force measurement data exceeds a preset threshold, an alarm can be issued or the operation of the superconducting magnet 100 can be stopped to avoid structural damage.

[0047] Furthermore, each support arm 332 can be equipped with two force measuring devices 340, which are symmetrically distributed on both sides of the guide field magnet 200. Specifically, the force measuring device 340 can be a pressure sensor, which can be attached or embedded in the corresponding position of the support arm 332 so that its end face can contact the slider 333. The symmetrical arrangement of the two force measuring devices 340 provides more accurate detection of the force on the guide field magnet 200.

[0048] The support arm 332 may also be provided with a clearance groove 335, which is used to avoid the guide field magnet 200. The shape of the clearance groove 335 can match the shape of the guide field magnet 200. When the guide field magnet 200 is installed on the slider 333, a part of the guide field magnet 200 can be located in the clearance groove 335.

[0049] In some embodiments, such as Figures 4-6 As shown, the fixed bracket 300 may further include a screw lifting mechanism 350 for driving the adjustment platform 330. The screw lifting mechanism 350 may include a motor 351 and a lead screw 352. The motor 351 drives the lead screw 352 to rotate, and the adjustment platform 330 is threadedly connected to the lead screw 352. The motor 351 may be a stepper motor 351 or a servo motor 351. The rotation of the motor 351 drives the lead screw 352 to rotate, and the lead screw 352 forms a threaded pair with the nut on the adjustment platform 330, converting the rotational motion into the linear motion of the adjustment platform 330. By controlling the direction of rotation and the number of rotations of the motor 351, the moving distance of the adjustment platform 330 can be precisely controlled, thereby realizing the adjustment of the position of the guide field magnet 200.

[0050] The guiding mechanism 320 includes two guide rods 321, which are spaced apart on the base 310. The adjusting platform 330 is mounted on the guide rods 321. The upper ends of the two guide rods 321 are fixed by a connecting plate 322, and the lower ends are fixed to the base 310. The motor 351 and the lead screw 352 can be mounted on the connecting plate 322. The guide rods 321 can be high-precision optical shafts that mate with linear bearings or guide holes on the adjusting platform 330. The parallel arrangement of the two guide rods 321 prevents the adjusting platform 330 from deflecting during movement, ensuring that the position of the guiding field magnet 200 remains unchanged.

[0051] The working process of the superconducting magnet system will be explained in detail below.

[0052] The base 310 of the fixed bracket 300 is fixed to the mounting reference surface of the superconducting magnet 100 by screws. The upper ends of the two guide rods 321 are fixed by the connecting plate 322, and the lower ends are fixed to the base 310. The motor 351 and the lead screw 352 are mounted on the connecting plate 322. The lead screw 352 passes through the slide 331 of the adjusting platform 330 and engages with the nut inside the slide 331. The two support arms 332 are fixedly connected to the slide 331, and the two sets of guiding field magnets 200 are respectively set on the two support arms 332. The two sets of guiding field magnets 200 are located on both sides of the axis of the neutron entrance aperture 120, and the magnetization direction is consistent, so that the two sets of guiding field magnets 200 form a guiding field opposite to the reverse magnetic field generated by the superconducting magnet 100. The pressure sensor installed on the support arm 332 is used to detect the force on the guiding field magnet 200.

[0053] Before the neutron scattering experiment begins, motor 351 is started, driving adjustment platform 330 to move along guide rod 321 via lead screw 352. This adjusts the guiding field magnet 200 to a preset position, ensuring that the guiding field generated by the guiding field magnet 200 precisely cancels the reverse magnetic field of superconducting magnet 100 outside neutron entrance aperture 120. Then, superconducting magnet 100 is started, and pressure sensors monitor the force data on guiding field magnet 200 in real time, transmitting the data to the monitoring system. If the value of any force sensor exceeds a threshold, the system can issue an alarm or stop the operation of superconducting magnet 100. The neutron beam first passes through the guiding field and then enters sample space 110 through neutron entrance aperture 120 of superconducting magnet 100. When the neutron beam passes through the guiding field region, its spin direction is protected by the guiding field, preventing it from flipping. This allows it to enter sample space 110 with high polarizability and interact with the sample, obtaining high-quality scattering data.

[0054] The superconducting magnet system of the above embodiment generates a guiding field opposite to the reverse magnetic field of the superconducting magnet 100 by setting a guiding field magnet 200 outside the neutron entrance aperture 120. This effectively cancels the reverse magnetic field on the neutron beam's path and improves neutron polarizability. By setting two sets of square permanent magnets arranged opposite each other and multiple magnets arranged axially, a uniform guiding field can be formed over a large space. The adjustable fixing bracket 300 allows for precise control of the guiding field position by adjusting the distance between the guiding field magnet 200 and the superconducting magnet 100. By adding a force sensor, the force on the guiding field magnet 200 can be monitored in real time, ensuring the structural safety of the fixing bracket 300.

[0055] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A superconducting magnet system, characterized in that, include: A superconducting magnet having a sample space and a neutron entrance aperture for allowing a neutron beam to flow into the sample space, wherein the superconducting magnet generates a reverse magnetic field outside the neutron entrance aperture that is opposite to the direction of the magnetic field inside the sample space. And a guiding field magnet, which is disposed outside the neutron entrance aperture to generate a guiding field. The direction of the guiding field is opposite to the direction of the reverse magnetic field generated by the superconducting magnet at the location of the guiding field, so as to counteract the reverse magnetic field generated by the superconducting magnet.

2. The superconducting magnet system according to claim 1, characterized in that, The guiding field magnets are provided in two sets, which are located on both sides of the axis of the neutron entrance aperture and are arranged facing each other. The magnetization direction of the two sets of guiding field magnets is the same, so as to form the guiding field between the two sets of guiding field magnets.

3. The superconducting magnet system according to claim 2, characterized in that, Each group of guiding field magnets includes multiple square permanent magnets, which are arranged sequentially along the axial direction of the neutron incident aperture.

4. The superconducting magnet system according to claim 2 or 3, characterized in that, The distance between the guiding field magnet and the superconducting magnet is adjustable.

5. The superconducting magnet system according to claim 4, characterized in that, It also includes a fixed support, which includes a base, a guide mechanism, and an adjustment platform. The base is fixed in position relative to the superconducting magnet. The guide mechanism is disposed on the base and arranged along the axial direction of the neutron entrance aperture. The guide field magnet is disposed on the adjustment platform. The adjustment platform is disposed on the guide mechanism and can move along the guide mechanism to adjust the distance between the guide field magnet and the superconducting magnet.

6. The superconducting magnet system according to claim 5, characterized in that, The adjustment platform includes a slide and two support arms fixed to the slide, and the two support arms are respectively used to set two sets of guide field magnets.

7. The superconducting magnet system according to claim 6, characterized in that, The adjustment platform also includes a slider located on the side of the support arm away from the superconducting magnet and movable relative to the support arm along the axial direction of the neutron entrance aperture, wherein the guiding field magnet is fixed to the slider.

8. The superconducting magnet system according to claim 7, characterized in that, It also includes a force measuring device, which is disposed on the side of the support arm near the slider, for contacting the guide field magnet and collecting the force data of the guide field magnet.

9. The superconducting magnet system according to claim 8, characterized in that, Each of the support arms is equipped with two force measuring devices, which are symmetrically distributed on both sides of the guide field magnet.

10. The superconducting magnet system according to claim 5, characterized in that, The fixed bracket also includes a screw lifting mechanism for driving the adjustment platform. The screw lifting mechanism includes a motor and a lead screw. The motor drives the lead screw to rotate, and the adjustment platform is threadedly connected to the lead screw.

Images