Superconducting magnet apparatus and magnetic resonance apparatus

Abstract

The application relates to a superconducting magnet device and a magnetic resonance device. The superconducting magnet device comprises a low-temperature holder with a containing space, a magnet assembly arranged in the interior of the low-temperature holder, and a cooling structure comprising a refrigerator and a heat exchange assembly, the refrigerator having a primary cold head and a secondary cold head, the heat exchange assembly being in heat exchange connection with the primary cold head and the secondary cold head, and the heat-exchanged heat exchange assembly further being in thermal coupling with the magnet assembly. The magnet assembly can be directly cooled by the heat exchange assembly, and the magnet assembly does not need to be immersed in liquid helium, so that the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of medical imaging equipment technology, and in particular to a superconducting magnet device and a magnetic resonance imaging device. Background Technology

[0002] In MR (Magnetic Resonance) equipment, the superconducting magnets in the superconducting magnet device are mostly NbTi superconducting magnets. These superconducting magnets (or coils) are usually encapsulated in liquid helium containers, which are fully or partially submerged in liquid helium. The superconducting magnet is cooled by the evaporation and condensation of liquid helium, ensuring its stable operation.

[0003] However, this method requires a liquid helium container volume of 1500L to 2000L, necessitating the filling of a large amount of liquid helium to cool the superconducting magnet. This increases liquid helium consumption and consequently, costs. Summary of the Invention

[0004] Therefore, it is necessary to address the high cost caused by the large amount of liquid helium used in current superconducting magnets by providing a superconducting magnet device and magnetic resonance equipment that reduces the amount of liquid helium used.

[0005] A superconducting magnet device, comprising:

[0006] Low-temperature holder with a storage space;

[0007] A magnet assembly is disposed inside the cryogenic holder; and

[0008] The cooling structure includes a refrigerator and a heat exchange assembly. The refrigerator has a primary cold head and a secondary cold head. The heat exchange assembly is heat-exchange connected to the primary cold head and the secondary cold head, and the heat exchange assembly after heat exchange is also thermally coupled to the magnet assembly.

[0009] In one embodiment, the heat exchange assembly includes a first heat exchanger and a second heat exchanger, the first heat exchanger being connected to the first-stage cold head for heat exchange, and the second heat exchanger being connected to the second-stage cold head for heat exchange.

[0010] In one embodiment, the superconducting magnet device further includes a power source, and the heat exchange assembly further includes a heat exchange inlet pipe and a heat exchange return pipe for the flow of a cooling medium. One end of the heat exchange inlet pipe is connected to the output end of the power source, and the other end of the heat exchange inlet pipe is connected to the first heat exchanger and the second heat exchanger. One end of the heat exchange return pipe is connected to the input end of the power source, and the other end of the heat exchange return pipe is connected to the first heat exchanger and the second heat exchanger.

[0011] In one embodiment, the refrigeration unit further includes a refrigeration inlet pipe and a refrigeration return pipe. One end of the refrigeration inlet pipe is connected to the output end of the power source, and the other end of the refrigeration inlet pipe is connected to the primary cold head and the secondary cold head. One end of the refrigeration return pipe is connected to the input end of the power source, and the other end of the refrigeration return pipe is connected to the primary cold head and the secondary cold head.

[0012] In one embodiment, the cryogenic holder further includes a radiation shielding layer and an outer container, the outer container being disposed outside the magnet assembly, the radiation shielding layer being located between the outer container and the magnet assembly, and the heat exchange assembly further includes a first connector connecting the primary cold head and the radiation shielding layer.

[0013] In one embodiment, the heat exchange assembly further includes a cooling pipe, one end of which is connected to the heat exchange inlet pipe and the other end of which is connected to the heat exchange return pipe, the cooling pipe surrounding the periphery of the magnet assembly.

[0014] In one embodiment, the heat exchange assembly further includes a second connector that connects the second heat exchanger to the magnet assembly.

[0015] In one embodiment, the heat exchange assembly further includes a third heat exchanger disposed at the input end of the first heat exchanger for cooling the cooling medium entering the first heat exchanger.

[0016] In one embodiment, the heat exchange assembly further includes a fourth heat exchanger disposed at the input end of the second heat exchanger for cooling the cooling medium entering the second heat exchanger.

[0017] A magnetic resonance imaging (MRI) device includes a superconducting magnet assembly having a scanning aperture, the superconducting magnet assembly comprising:

[0018] Low-temperature holder with a storage space;

[0019] A magnet assembly is disposed inside the cryogenic holder; and

[0020] The cooling structure includes a refrigerator and a heat exchange assembly. The refrigerator has a primary cold head and a secondary cold head. The heat exchange assembly is heat-exchange connected to the primary cold head and the secondary cold head, and the heat exchange assembly after heat exchange is also thermally coupled to the magnet assembly.

[0021] By adopting the above technical solution, the present invention has at least the following technical effects:

[0022] The superconducting magnet device and magnetic resonance equipment of the present invention have a primary and a secondary cold head of a cryostat connected to a magnet assembly via a heat exchange assembly. The cooling capacity of the primary and secondary cold heads can exchange heat with the heat exchange assembly, reducing the temperature of the heat exchange assembly, which in turn cools the magnet assembly, thus lowering its temperature. The heat exchange assembly directly cools the magnet assembly, instead of using the traditional liquid helium immersion method to cool the superconducting coil. This effectively addresses the high cost associated with the current use of large amounts of liquid helium in superconducting magnets, eliminating the need for liquid helium immersion and reducing costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a superconducting magnet device according to an embodiment of the present invention;

[0024] Figure 2 for Figure 1 A partial enlarged view of the superconducting magnet device shown;

[0025] Figure 3 This is a schematic diagram of a superconducting magnet device according to another embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of a superconducting magnet device according to another embodiment of the present invention;

[0027] Figure 5 for Figure 4 The diagram shows the control relationship of the flow control valve in the superconducting magnet device.

[0028] The components are as follows: 100, superconducting magnet device; 110, cryogenic holder; 111, outer container; 112, magnet assembly; 113, radiation shielding layer; 120, cooling structure; 121, refrigerator; 1211, primary cold head; 1212, secondary cold head; 1213, refrigeration inlet pipe; 1214, refrigeration return pipe; 122, heat exchange assembly; 1221, first heat exchanger; 1222, second heat exchanger; 1223, heat exchange inlet pipe; 1224, heat exchange return pipe; 1225, first connector; 1226, cooling pipeline; 1227, third heat exchanger; 1228, fourth heat exchanger; 1229, flow control valve; 123, power source. Detailed Implementation

[0029] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0035] See Figures 1 to 3 This invention provides a superconducting magnet device 100. This superconducting magnet device 100 is used in magnetic resonance imaging (MRI) equipment to image a specific area, obtaining image information of that area to facilitate diagnosis by medical personnel. It is understood that the imaging area can be the head, chest, abdomen, limbs, or other parts of a human or animal body, or it can be tissues such as the breast, heart, or liver. Of course, in other embodiments of this invention, the imaging area can also be other locations requiring imaging.

[0036] Current magnetic resonance imaging (MRI) devices encapsulate superconducting magnets in liquid helium. The superconducting magnets are cooled through the evaporation and condensation of the liquid helium, ensuring their stable operation. However, the liquid helium containers in MRI devices are very large, and a significant amount of liquid helium is required to ensure effective cooling of the superconducting magnets, which increases the cost of liquid helium.

[0037] To address this, the present invention provides a novel superconducting magnet device 100, which achieves cooling internally without immersing the superconducting coil in liquid helium, thereby reducing costs. The specific structure of the superconducting magnet device 100 is described in detail below.

[0038] See Figures 1 to 3In one embodiment, the superconducting magnet device 100 includes a cryogenic holder 110, a magnet assembly 112, and a cooling structure 120. The cryogenic holder 110 includes an outer container 111 and a radiation shielding layer 113, which can be coaxially or non-coaxially arranged. The cryogenic holder 110 can form a receiving space in which the magnet assembly 112 can be housed. The magnet assembly 112 is disposed inside the outer container 111, and the radiation shielding layer 113 is located between the outer container 111 and the magnet assembly 112. The cooling structure 120 includes a refrigerator 121 and a heat exchange assembly 122 having a cooling medium. The refrigerator 121 has a primary cold head 1211 and a secondary cold head 1212. The heat exchange assembly 122 is heat-exchange connected / thermally coupled to the primary cold head 1211 and the secondary cold head 1212. After heat exchange, the heat exchange assembly 122 is also connected to the magnet assembly 112 for cooling the magnet assembly 112. Optionally, both the outer container 111 and the radiation shielding layer 113 can be configured as a double-layer structure. The figure only schematically shows the outer cylinder of the outer container 111 and the outer cylinder of the radiation shielding layer 113. In the actual structure, an inner cylinder of the outer container 111 and an inner cylinder of the radiation shielding layer 113 are also provided. Thus, the outer cylinder and inner cylinder of the outer container 111 form an annular structure, and the outer cylinder and inner cylinder of the radiation shielding layer 113 also form an annular structure. The annular structure formed by the radiation shielding layer 113 is located inside the annular structure formed by the outer container 111, and the internal space of the annular structure formed by the radiation shielding layer 113 is the accommodating space.

[0039] The cryogenic holder 110 is the main structure of the superconducting magnet device 100, used to house the various components of the superconducting magnet device 100 and maintain it at a low temperature to ensure the performance of the superconducting magnet device 100. Specifically, the cryogenic holder 110 includes an outer container 111, a magnet assembly 112 disposed within the outer container 111, and a radiation shielding layer 113 disposed between the outer container 111 and the magnet assembly 112. The outer container 111 has a through hole extending in the axial direction, which serves as the magnet hole for the magnetic resonance imaging device. The outer container 111 is an annular closed structure, and the magnet assembly 112 is coaxially arranged with the outer container 111, disposed inside the outer container 111.

[0040] There is a space between the magnet assembly 112 and the outer container 111, which is a vacuum environment. The vacuum environment reduces the radiation of cold energy from the magnet assembly 112 and minimizes the conduction of external heat to the inner magnet assembly 112, ensuring that the magnet assembly 112 is in a low-temperature environment. Furthermore, a radiation shielding layer 113 is installed in this space, surrounding the magnet assembly 112. The radiation shielding layer 113 further isolates external radiated heat, preventing external heat from radiating to the magnet assembly 112.

[0041] The cooling structure 120 is disposed on the cryogenic holder 110. The cooling structure 120 includes a refrigerator 121 and a heat exchange component 122. The cooling structure 120 is partially or entirely disposed on one side of the outer container 111 of the cryogenic holder 110. The refrigerator 121 can cool the magnet component 112 and the radiation shielding layer 113 of the cryogenic holder 110, reduce the temperature of the radiation shielding layer 113, and prevent the radiation shielding layer 113 from transferring heat to the magnet component 112, thereby reducing the temperature of the magnet component 112, ensuring the performance of the magnet component 112, and preventing overrunning.

[0042] Understandably, the magnet assembly 112 may include a coil frame that supports the superconducting coil. The superconducting coil and the coil frame are combined and placed in the outer container 111, located inside the radiation shielding layer 113. Moreover, the cryogenic holder 110 does not require an inner container. While reducing the size of the superconducting magnet device 100, a larger storage space can be obtained, which is beneficial for setting up a high-field superconducting coil.

[0043] Of course, the cryogenic holder 110 may also include an inner container. In this case, the inner container is disposed within the outer container 111 and located inside the radiation shielding layer 113, while the magnet assembly 112 is located within the inner container. Moreover, the inner container no longer contains a cooling medium such as liquid helium. In this way, the cooling structure 120 can directly conduct cooling to the internal magnet assembly 112 without immersing the superconducting coil in a cooling medium such as liquid helium, thereby reducing costs.

[0044] Specifically, the cooling structure 120 includes a refrigerator 121 and a heat exchange assembly 122 with a cooling medium. The refrigerator 121 has a primary cold head (first-stage cold head) 1211 and a secondary cold head (second-stage cold head) 1212. The heat exchange assembly 122 is heat-exchange connected to the primary cold head 1211 and the secondary cold head 1212. After heat exchange, the heat exchange assembly 122 is also thermally coupled to a magnet assembly 112 for cooling the magnet assembly 112. In this embodiment, thermal coupling refers to heat exchange between the two components.

[0045] The primary cold head 1211 and the secondary cold head 1212 are respectively connected to the heat exchange assembly 122 for heat exchange. When the refrigerator 121 is working, it can generate cooling capacity. After the primary cold head 1211 and the secondary cold head 1212 exchange heat with the heat exchange assembly 122, the heat exchange assembly 122 can absorb the cooling capacity of the primary cold head 1211 and the secondary cold head 1212 to reduce the temperature of the cooling medium therein. Then, the heat exchange assembly 122 absorbs the cooling capacity through the cooling medium and uses the cooling capacity to control the temperature of the magnet assembly 112.

[0046] Understandably, after absorbing the cooling energy from the primary cold head 1211 and the secondary cold head 1212, the heat exchange component 122 can directly cool the magnet assembly 112, eliminating the need for cooling the superconducting magnet with liquid helium and saving the liquid helium filling the magnet assembly 112. Furthermore, the radiation shielding layer 113 located outside the magnet assembly 112 will also experience temperature increases during operation, requiring cooling as well. Optionally, the radiation shielding layer 113 is connected to the secondary cold head 1212, and the cooling energy from the secondary cold head 1212 is transferred to the radiation shielding layer 113 for cooling. After the cooling energy from the secondary cold head 1212 is transferred to the radiation shielding layer 113, it can cool the radiation shielding layer 113, thereby reducing its temperature.

[0047] The superconducting magnet device 100 of the above embodiment is connected to the magnet assembly 112 through a heat exchange component 122, and is also connected to the primary cold head 1211 and the secondary cold head 1212 through the heat exchange component 122. This allows the heat exchange component 122 to absorb the cooling energy of the primary cold head 1211 and the secondary cold head 1212 and directly cool the magnet assembly 112. This effectively solves the problem of high cost caused by the use of a large amount of liquid helium in current superconducting magnets, eliminating the need to soak the magnet assembly 112 in liquid helium, thus reducing costs.

[0048] Optionally, the outer container 111 includes a first outer cylinder, a first inner cylinder, and a first end plate. The first inner cylinder and the first outer cylinder are hollow cylindrical structures, respectively arranged radially from the center inwards. First end plates, which are annular structures, are respectively provided at both ends of the first inner cylinder, connecting to the first inner cylinder and the first outer cylinder to seal them respectively. Optionally, the outer container 111 is made of metal or composite material; further, it can be made of carbon steel or stainless steel.

[0049] Optionally, the inner container includes a second outer cylinder, a second inner cylinder, and second end plates. The second inner cylinder and the second outer cylinder are hollow cylindrical structures, respectively arranged radially from the center inwards. Second end plates, which are annular structures, are respectively provided at both ends of the second inner cylinder, connecting to the second inner cylinder and the second outer cylinder to seal them respectively. Optionally, the inner container is made of metal or composite material; further, it can be made of carbon steel or stainless steel.

[0050] Optionally, the radiation shielding layer 113 includes a third outer cylinder, a third inner cylinder, and a third end plate. The third inner cylinder and the third outer cylinder are hollow cylindrical structures, respectively arranged radially from the center inwards. Third end plates are respectively provided at both ends of the third inner cylinder. The third end plates are annular structures, connected to the third inner cylinder and the third outer cylinder respectively, to seal them. Specifically, the third inner cylinder is located between the first inner cylinder and the second inner cylinder, the third outer cylinder is located between the first outer cylinder and the second outer cylinder, and the third end plate is located between the first end plate and the second end plate.

[0051] See Figures 1 to 3 In one embodiment, the heat exchange assembly 122 includes a first heat exchanger 1221 and a second heat exchanger 1222. The first heat exchanger 1221 is heat-exchange connected to a first-stage cold head 1211, and the second heat exchanger 1222 is heat-exchange connected to a second-stage cold head 1212, and cools the magnet assembly 112. The first heat exchanger 1221 and the second heat exchanger 1222 are connected in series, and a cooling medium flows through the first heat exchanger 1221 and the second heat exchanger 1222.

[0052] Meanwhile, the first heat exchanger 1221 is connected to the first-stage cold head 1211 for heat exchange, and the first heat exchanger 1221 also allows the cooling medium in the first-stage cold head 1211 to flow. In this way, when the refrigerator 121 is working, the cooling capacity of the first-stage cold head 1211 can be transferred to the cooling medium in the first-stage cold head 1211. After the cooling medium flows to the first heat exchanger 1221, it can exchange heat with the cooling medium in the first heat exchanger 1221 to reduce the temperature of the cooling medium. At the same time, the cooling medium absorbs the heat from the cooling medium and flows back to the first-stage cold head 1211.

[0053] It is worth noting that the first heat exchanger 1221 and the second heat exchanger 1222 are connected in series. After the cooling medium flows through the first heat exchanger 1221 and the second heat exchanger 1222 in sequence, the cooling medium can be cooled in stages. This avoids the sudden drop in temperature of the cooling medium during the exchange of cold energy, which would prevent it from effectively absorbing the cold energy. This avoids the waste of cold energy, improves the efficiency of cold energy utilization, and ensures the cooling effect of the cooling medium.

[0054] In the cooling medium cooled by the primary cold head 1211, a portion flows to the first heat exchanger 1221, and the remainder flows to the secondary cold head 1212, where it continues to cool the medium and lower its temperature. Simultaneously, the cooled medium after heat exchange in the first heat exchanger 1221 flows to the second heat exchanger 1222, where heat exchange further reduces the temperature of the medium.

[0055] Furthermore, the second heat exchanger 1222 is heat-exchange connected to the secondary cold head 1212, and the second heat exchanger 1222 also allows the cooling medium in the secondary cold head 1212 to flow. Thus, when the refrigerator 121 is operating, the cooling capacity of the secondary cold head 1212 can be transferred to the cooling medium in the secondary cold head 1212. After flowing to the second heat exchanger 1222, the cooling medium can exchange heat with the cooling medium in the second heat exchanger 1222 to reduce the temperature of the cooling medium in the second heat exchanger 1222. Simultaneously, the cooling medium absorbs heat from the cooling medium and flows back to the secondary cold head 1212. After absorbing the cooling capacity, the cooling medium in the second heat exchanger 1222 can cool the magnet assembly 112 to reduce its temperature and ensure reliable operation. The cooling method between the second heat exchanger 1222 and the magnet assembly 112 will be mentioned later.

[0056] Optionally, the first heat exchanger 1221 and the second heat exchanger 1222 are tubular heat exchangers, and the cooling medium flowing in the inflow direction exchanges heat with the cooling medium flowing in the inflow direction in the first heat exchanger 1221 or the second heat exchanger 1222. Of course, in other embodiments of the present invention, the first heat exchanger 1221 and the second heat exchanger 1222 can also be other components capable of heat exchange, such as plate heat exchangers or U-tube heat exchangers.

[0057] Optionally, the first heat exchanger 1221 and the second heat exchanger 1222 are made of different materials. Understandably, the power and cooling capacity generated by the primary cold head 1211 and the secondary cold head 1212 of the refrigerator 121 are different during operation. Typically, the temperature of the primary cold head 1211 is 30K–50K, with a cooling power of approximately 45W. Typically, the temperature of the secondary cold head 1212 is approximately 4.2K, with a cooling power of approximately 1W. Because the cooling capacity generated by the primary cold head 1211 and the secondary cold head 1212 is different, the cooling capacity exchanged by the first heat exchanger 1221 and the second heat exchanger 1222 also differs. Optionally, the first heat exchanger 1221 is a 30K–50K heat exchanger, and the second heat exchanger 1222 is a 3K–5K heat exchanger. For example, the first heat exchanger 1221 is a 50K heat exchanger, and the second heat exchanger 1222 is a 4.2K heat exchanger.

[0058] Understandably, the first-stage cold head 1211 includes a first cooler and a first copper block, which is connected to the first heat exchanger 1221. That is, after the first cooler cools the cooling medium, the cooling capacity of the medium is transferred to the first copper block. Because the first copper block establishes a cooling capacity transfer path with the first heat exchanger 1221, the cooling capacity of the medium can be transferred to the first heat exchanger 1221 to cool the cooling medium within it and lower its temperature. For simplicity in the following description, it will be directly stated that the first heat exchanger 1221 exchanges heat with the cooling medium.

[0059] The secondary cold head 1212 includes a second cooler and a second copper block, which is connected to the second heat exchanger 1222. That is, after the second cooler cools the cooling medium, the cooling capacity of the medium is transferred to the second copper block. Because the second copper block establishes a cooling capacity transfer path with the second heat exchanger 1222, the cooling capacity of the cooling medium can be transferred to the second heat exchanger 1222 to cool the cooling medium within it and lower its temperature. For simplicity, the following description will directly state that the second heat exchanger 1222 exchanges heat with the cooling medium.

[0060] See Figure 1 and Figure 2 In one embodiment, the outer container 111 has a cold head cavity for mounting a primary cold head 1211 and a secondary cold head 1212. A first heat exchanger 1221 is connected to a first copper block of the primary cold head 1211 in the cold head cavity, and a second heat exchanger 1222 is connected to a second copper block of the secondary cold head 1212 in the cold head cavity. See also Figure 3 Of course, in other embodiments of the present invention, the outer container 111 may also not have a cold head cavity, the first heat exchanger 1221 is connected to the first-stage cold head 1211 in the space between the outer container 111 and the inner container, and the second heat exchanger 1222 is connected to the second-stage cold head 1212 in the space between the outer container 111 and the inner container.

[0061] See Figures 1 to 3 In one embodiment, the heat exchange assembly 122 further includes a power source 123 and a heat exchange inlet pipe 1223 and a heat exchange return pipe 1224 for the flow of the cooling medium. One end of the heat exchange inlet pipe 1223 is connected to the output end of the power source 123, and the other end of the heat exchange inlet pipe 1223 is connected to the first heat exchanger 1221 and the second heat exchanger 1222. One end of the heat exchange return pipe 1224 is connected to the input end of the power source 123, and the other end of the heat exchange return pipe 1224 is connected to the first heat exchanger 1221 and the second heat exchanger 1222.

[0062] Power source 123 provides power for the movement of the cooling medium, enabling it to circulate within the first heat exchanger 1221 and the second heat exchanger 1222. Specifically, the heat exchange inlet pipe 1223 is connected in series with the first heat exchanger 1221 and the second heat exchanger 1222, and is also connected to the output end of power source 123. The cooling medium output from power source 123 can enter the first heat exchanger 1221 and the second heat exchanger 1222 through the heat exchange inlet pipe 1223. Heat exchange return pipe 1224 is connected in series with the first heat exchanger 1221 and the second heat exchanger 1222, and is also connected to the input end of power source 123. After the cooling medium flows through the second heat exchanger 1222 and cools the magnet assembly 112, the cooling medium will flow back to the power source 123 through the first heat exchanger 1221, the second heat exchanger 1222 and the heat exchange return pipe 1224, and be circulated and transported by the power source 123.

[0063] In other words, the heat exchange inlet pipe 1223 and the heat exchange return pipe 1224 form a complete circuit connecting the first heat exchanger 1221, the second heat exchanger 1222, and the power source 123. When the power source 123 outputs cooling medium to the heat exchange inlet pipe 1223, the cooling medium first enters the first heat exchanger 1221 and exchanges heat with the cooling medium supplied by the primary cold head 1211 in the first heat exchanger 1221, reducing the temperature of the cooling medium in the first heat exchanger 1221. The cooled cooling medium then enters the second heat exchanger 1222 through the heat exchange inlet pipe 1223 and exchanges heat with the cooling medium supplied by the secondary cold head 1212 in the second heat exchanger 1222, further reducing the temperature of the cooling medium in the second heat exchanger 1222. The further cooled cooling medium can then cool the magnet assembly 112, thereby reducing its temperature.

[0064] The cooling medium for the magnet assembly 112 in the second heat exchanger 1222 enters the heat exchange return pipe 1224. In other words, the cooled medium, after absorbing heat, flows back to the heat exchange return pipe 1224, and then sequentially passes through the first heat exchanger 1221 and the second heat exchanger 1222 before returning to the power source 123. Subsequently, the power source 123 compresses the cooling medium, turning it into a high-temperature, high-pressure gas, which then re-enters the first heat exchanger 1221 and the second heat exchanger 1222 through the heat exchange inlet pipe 1223 for heat exchange. This process repeats continuously, achieving the cooling of the magnet assembly 112.

[0065] Optionally, the power source 123 is a power pump, which realizes the circulation and transportation of the cooling medium. In another embodiment of the present invention, the power source 123 may also be a compressor. Of course, the power source 123 may also be other components capable of realizing the circulation of the cooling medium.

[0066] See Figures 1 to 3In one embodiment, the refrigerator 121 further includes a refrigeration inlet pipe 1213 and a refrigeration return pipe 1214. One end of the refrigeration inlet pipe 1213 is connected to the output end of the power source 123, and the other end of the refrigeration inlet pipe 1213 is connected to the first-stage cold head 1211 and the second-stage cold head 1212. One end of the refrigeration return pipe 1214 is connected to the input end of the power source 123, and the other end of the refrigeration return pipe 1214 is connected to the first-stage cold head 1211 and the second-stage cold head 1212.

[0067] Power source 123 also provides power for the flow of the refrigerant, enabling the cooling medium in the refrigerator 121 to circulate between the primary cold head 1211 and the secondary cold head 1212. Specifically, the refrigerant inlet pipe 1213 is connected to the output end of power source 123, and is also connected in series to the primary cold head 1211 and the secondary cold head 1212. The refrigerant delivered by power source 123 can sequentially enter the primary cold head 1211 and the secondary cold head 1212. The refrigerant return pipe 1214 is connected in series to the output ends of the primary cold head 1211 and the secondary cold head 1212, and extends from the refrigerator 121 to the input end of power source 123. After the cooling medium flows through the secondary cold head 1212 and exchanges heat with the cooling medium in the second heat exchanger 1222, the cooling medium will flow back to power source 123 via the secondary cold head 1212, the primary cold head 1211, and the refrigerant return pipe 1214, and be circulated by power source 123.

[0068] In other words, the cooling inlet pipe 1213 and the cooling return pipe 1214 form a complete circuit with the first-stage cold head 1211, the second-stage cold head 1212, and the power source 123. Furthermore, this circuit is relatively independent from the circuit formed by the power source 123, the first heat exchanger 1221, the second heat exchanger 1222, the heat exchange inlet pipe 1223, and the heat exchange return pipe 1224. Heat exchange is achieved through parallel connection, so that the cooling capacity of the cooling medium can be transferred to the cooling medium to cool the magnet assembly 112.

[0069] After the power source 123 outputs cooling medium to the refrigeration inlet pipe 1213, the cooling medium first enters the first-stage cold head 1211, where it is cooled to lower its temperature. A portion of the cooled medium then enters the first heat exchanger 1221, where it exchanges heat with the cooling medium. The remaining portion enters the second-stage cold head 1212, where it further cools the medium, further reducing its temperature. Finally, the cooled medium enters the second heat exchanger 1222, where it exchanges heat with the cooling medium to lower its temperature.

[0070] The cooling medium after heat exchange in the first heat exchanger 1221 and the second heat exchanger 1222 enters the refrigeration return pipe 1214, and then flows back to the power source 123 through the first-stage cold head 1211 and the second-stage cold head 1212. Subsequently, the power source 123 compresses the cooling medium, turning it into a high-temperature, high-pressure gas, which then enters the first-stage cold head 1211 and the second-stage cold head 1212 through the refrigeration inlet pipe 1213. The first-stage cold head 1211 and the second-stage cold head 1212 cool the cooling medium, followed by heat exchange, and this process is repeated.

[0071] See Figures 1 to 3 In one embodiment of the present invention, the cryogenic holder further includes a first connector 1225, which connects the primary cold head 1211 and the radiation shielding layer 113, and is used to transfer the cooling capacity of the radiation shielding layer 113. That is, the first connector 1225 establishes a cooling capacity transfer path between the primary cold head 1211 and the radiation shielding layer 113, and realizes heat exchange between the primary cold head 1211 and the radiation shielding layer 113 through the first connector 1225, so as to reduce the temperature of the radiation shielding layer 113.

[0072] Specifically, one end of the first connector 1225 is connected to the first copper block of the first-stage cold head 1211, and the other end of the first connector 1225 is connected to the radiation shielding layer 113. The first connector 1225 can transfer the cooling energy of the cooling medium in the first-stage cold head 1211 to the radiation shielding layer 113, thereby reducing the temperature of the radiation shielding layer 113.

[0073] Optionally, there are multiple first connectors 1225, which are spaced apart and connected to different positions of the radiation shielding layer 113. This ensures the effectiveness of the first connectors 1225 in transferring cold energy, thus ensuring the cooling effect of the radiation shielding layer 113 and consequently ensuring the effectiveness of the radiation shielding layer 113 in isolating external heat. Optionally, the first connectors 1225 are made of a high thermal conductivity material. Further, the first connectors 1225 are copper strips or other thermally conductive components.

[0074] In another embodiment of the present invention, the heat exchange assembly 122 includes a heat exchange pipeline, the two ends of which are respectively connected to a heat exchange inlet pipe 1223 and a heat exchange return pipe 1224. The heat exchange pipeline surrounds the periphery of the radiation shielding layer 113. The heat exchange pipeline is supplied with a cooling medium in the first heat exchanger 1221 to cool the radiation shielding layer 113.

[0075] In other words, the heat exchange piping is arranged around the outer or inner periphery of the radiation shielding layer 113. One end of the heat exchange piping is connected to the heat exchange inlet pipe 1223, and the other end is connected to the heat exchange return pipe 1224. The cooling medium that exchanges heat with the cooling medium in the first heat exchanger 1221 can enter the heat exchange piping through the heat exchange inlet pipe 1223. During the flow of the cooling medium in the heat exchange piping, the cooling medium can exchange heat with the radiation shielding layer 113, absorbing the heat of the radiation shielding layer 113 and reducing the temperature of the radiation shielding layer 113. After absorbing heat, the cooling medium continues to flow in the heat exchange piping and enters the heat exchange return pipe 1224 to return to the power source 123.

[0076] Understandably, the primary cooling head 1211 can be connected to the radiation shielding layer 113 via the first connector 1225 to cool the radiation shielding layer 113, or it can be surrounded by the heat exchange pipes to cool the radiation shielding layer 113. In this embodiment, the primary cooling head 1211 is connected to the radiation shielding layer 113 via the first connector 1225.

[0077] See Figures 1 to 3 In one embodiment of the present invention, the heat exchange assembly 122 further includes a cooling pipe 1226, one end of which is connected to the heat exchange inlet pipe 1223 and the other end of which is connected to the heat exchange return pipe 1224. The cooling pipe 1226 is arranged around the periphery of the magnet assembly 112 and is used to cool the magnet assembly 112.

[0078] In other words, the cooling pipe 1226 surrounds the outer periphery of the magnet assembly 112. One end of the cooling pipe 1226 is connected to the heat exchange inlet pipe 1223, and the other end is connected to the heat exchange return pipe 1224. The cooling medium that exchanges heat with the cooling medium in the second heat exchanger 1222 can enter the cooling pipe 1226 through the heat exchange inlet pipe 1223. During the flow of the cooling medium in the cooling pipe 1226, the cooling medium can exchange heat with the magnet assembly 112, absorb the heat of the magnet assembly 112, and reduce the temperature of the magnet assembly 112. After absorbing heat, the cooling medium continues to flow in the cooling pipe 1226 and enters the heat exchange return pipe 1224 to return to the power source 123.

[0079] In another embodiment of the present invention, the heat exchange assembly 122 further includes a second connector connecting the second heat exchanger 1222 and the magnet assembly 112. The second connector is used to transfer the cooling capacity of the magnet assembly 112. That is, the second connector establishes a cooling capacity transfer path between the second heat exchanger 1222 and the magnet assembly 112, and heat exchange between the second heat exchanger 1222 and the magnet assembly 112 is realized through the second connector to reduce the temperature of the magnet assembly 112.

[0080] Specifically, one end of the second connector is connected to the second heat exchanger 1222, and the other end of the second connector is connected to the magnet assembly 112. The second connector can transfer the cooling capacity of the cooling medium in the second heat exchanger 1222 to the magnet assembly 112, thereby reducing the temperature of the magnet assembly 112.

[0081] Optionally, there are multiple second connectors, spaced apart, each connecting to a different position on the magnet assembly 112. This ensures the effective transfer of cooling energy by the second connectors, thus guaranteeing the cooling effect of the magnet assembly 112. Optionally, the second connectors are made of a high thermal conductivity material. Further, the second connectors are copper strips or other thermally conductive components.

[0082] See Figures 1 to 3 In one embodiment, the heat exchange assembly 122 further includes a third heat exchanger 1227, which is disposed at the input end of the first heat exchanger 1221 and is used to cool the cooling medium entering the first heat exchanger 1221. That is, the third heat exchanger 1227 is disposed between the power source 123 and the first heat exchanger 1221, and the heat exchange inlet pipe 1223 connects the third heat exchanger 1227 and the first heat exchanger 1221 in series. The cooling medium delivered by the power source 123 passes through the third heat exchanger 1227 and then enters the first heat exchanger 1221.

[0083] Understandably, if the cooling medium supplied by the power source 123 directly enters the first heat exchanger 1221 for cooling, the cooling medium cannot be cooled to the required temperature in time, resulting in wasted cooling capacity and affecting the cooling effect. Therefore, a third heat exchanger 1227 is added to the superconducting magnet device 100 of the present invention. The cooling medium is initially cooled by the third heat exchanger 1227, and the cooling medium cooled by the third heat exchanger 1227 then enters the first heat exchanger 1221.

[0084] Optionally, the third heat exchanger 1227 is a heat exchanger with a temperature range of 250K to 300K. For example, the third heat exchanger 1227 is a 300K heat exchanger. The heat exchange inlet pipe 1223 and the heat exchange return pipe 1224 are respectively connected to the third heat exchanger 1227. The residual cooling capacity of the cooling medium in the heat exchange return pipe 1224 cools the high-pressure cooling medium in the heat exchange inlet pipe 1223, initially reducing the temperature of the cooling medium in the heat exchange inlet pipe 1223 and improving the utilization efficiency of the cooling capacity. Simultaneously, it also facilitates the cooling of the cooling medium in the first heat exchanger 1221.

[0085] See Figure 3In one embodiment, the heat exchange assembly 122 further includes a fourth heat exchanger 1228, which is disposed at the input end of the second heat exchanger 1222 and is used to cool the cooling medium entering the second heat exchanger 1222. That is, the fourth heat exchanger 1228 is disposed between the first heat exchanger 1221 and the second heat exchanger 1222. The cooling medium after heat exchange in the first heat exchanger 1221 first enters the fourth heat exchanger 1228 for cooling, and then enters the second heat exchanger 1222.

[0086] After adding a fourth heat exchanger 1228 between the first heat exchanger 1221 and the second heat exchanger 1222, the cooling medium output from the first heat exchanger 1221 is initially cooled by the fourth heat exchanger 1228, and then further cooled by the second heat exchanger 1222. In this way, the second heat exchanger 1222 can cool the cooling medium better and improve the utilization rate of cooling capacity.

[0087] Optionally, the fourth heat exchanger 1228 is a heat exchanger with a temperature of 10K to 15K. For example, the fourth heat exchanger 1228 is a 10K heat exchanger. The heat exchange inlet pipe 1223 and the heat exchange return pipe 1224 are respectively connected to the fourth heat exchanger 1228. The residual cooling capacity of the cooling medium in the heat exchange return pipe 1224 cools the high-pressure cooling medium in the heat exchange inlet pipe 1223, initially reducing the temperature of the cooling medium in the heat exchange inlet pipe 1223 and improving the utilization efficiency of the cooling capacity. Simultaneously, it also facilitates the cooling of the cooling medium in the third heat exchanger 1227.

[0088] It is worth noting that the superconducting magnet device 100 may or may not include a fourth heat exchanger 1228. See [link / reference] Figure 1 and Figure 2 A fourth heat exchanger 1228 is provided between the first heat exchanger 1221 and the second heat exchanger 1222. (See also...) Figure 3 The first heat exchanger 1221 is directly connected to the second heat exchanger 1222, eliminating the need for the fourth heat exchanger 1228.

[0089] See Figure 4 In one embodiment, the heat exchange assembly 122 further includes a flow control valve 1229, which is disposed in the heat exchange inlet pipe 1223 and is used to control the flow rate of the cooling medium in the heat exchange inlet pipe 1223. After the flow control valve 1229 adjusts the flow rate of the cooling medium in the heat exchange inlet pipe 1223, the temperature can be controlled.

[0090] Specifically, adjusting the flow control valve 1229 increases the flow rate of the cooling medium, thereby increasing the cooling effect. Adjusting the flow control valve 1229 decreases the flow rate of the cooling medium, thereby decreasing the cooling effect. Furthermore, the flow control valve 1229 controls the flow coefficient by controlling the number of opening turns, thus controlling the flow rate of the cooling medium. The relationship between the flow coefficient and the number of opening turns is as follows: Figure 5 As shown, the conversion relationship between flow rate and temperature can be linear or nonlinear. Theoretically, the higher the flow rate, the lower the temperature on the coil. The specific relationship can be determined through simulation by collecting different sets of flow rate and temperature data.

[0091] See Figures 1 to 3 The superconducting magnet device 100 of the present invention achieves the transfer of cooling energy between the primary cold head 1211 and the radiation shielding layer 113 through a first connector, and achieves the transfer of cooling energy between the secondary cold head 1212 and the magnet assembly 112 through the cooperation of the second heat exchanger 1222 and the cooling pipe 1226. This eliminates the need to immerse the superconducting coil in liquid helium, saving a significant amount of liquid helium and reducing costs. Furthermore, the superconducting magnet device 100 of the present invention has a simple structure and is easy to use. Optionally, the cooling medium is liquid helium, hyperpolarized material, etc. Optionally, the cooling medium is liquid helium, hyperpolarized material, etc.

[0092] In use, the superconducting magnet device 100 of this invention outputs a high-pressure cooling medium and a high-pressure heat transfer medium from the power source 123 (i.e., the compressor). The high-pressure cooling medium enters the heat exchange inlet pipe 1223, and the high-pressure cooling medium enters the refrigerator 121. The cooling medium, after passing through the heat exchange inlet pipe 1223 and then through the third heat exchanger 1227 and the first heat exchanger 1221, is cooled to approximately 50K. Simultaneously, the cooling medium in the second heat exchanger 1222 continues to flow along the heat exchange inlet pipe 1223, passes through the third heat exchanger 1227, and enters the second heat exchanger 1222, where it is cooled to approximately 4K. It then enters the cooling pipe, cooling the cooling pipe to approximately 4K. Furthermore, the cooling pipe exchanges heat with the magnet assembly 112, cooling the magnet assembly 112 to approximately 4K as well. After heat exchange, the temperature of the cooling medium in the cooling pipes rises and returns to the power source 123 via the heat exchange return pipe 1224, passing sequentially through the second heat exchanger 1222, the fourth heat exchanger 1228, the first heat exchanger 1221, and the third heat exchanger 1227. During this cycle, the power source 123 generates a pressure difference, causing the cooling medium and the cooling medium to circulate, and driving the cooling energy generated by the refrigerator 121 to cover the cooling pipes on the surface of the magnet assembly 112, thereby cooling the magnet assembly 112.

[0093] The present invention also provides a magnetic resonance device, including a gradient coil, a radio frequency coil, and a superconducting magnet device 100. The superconducting magnet device 100 has a scanning aperture, the radio frequency coil is disposed in the scanning aperture, and the gradient coil is located between the radio frequency coil and the superconducting magnet device 100. The superconducting magnet device 100 includes: a cryogenic holder 110 and a magnet assembly 112. The cryogenic holder 110 includes an outer container 111 and a radiation shielding layer 113 arranged coaxially. The magnet assembly 112 is disposed inside the outer container 111, and the radiation shielding layer 113 is located between the outer container 111 and the magnet assembly 112. The device also includes a cooling structure 120, which includes a refrigerator 121 and a heat exchange assembly 122 with a cooling medium. The refrigerator 121 has a primary cold head 1211 and a secondary cold head 1212. The heat exchange assembly 122 is heat-exchange connected to the primary cold head 1211 and the secondary cold head 1212. The heat exchange assembly 122 is also connected to the magnet assembly 112 after heat exchange for cooling the magnet assembly 112.

[0094] The superconducting magnet device 100 in the magnetic resonance imaging (MRI) device of the present invention is the same as the superconducting magnet device 100 in the above embodiments. The specific structure and working principle of the two are essentially the same, and will not be described in detail here. After adopting the superconducting magnet device 100, the MRI device does not need to soak the magnet assembly 112 in liquid helium, reducing the amount of liquid helium used and thus reducing the cost of liquid helium.

[0095] Based on the aforementioned magnetic resonance device structure, this application also proposes a cooling method for the magnetic resonance device, comprising: performing primary heat exchange cooling on the cooling medium in the heat exchange assembly 122 through a primary cold head 1211; performing secondary heat exchange cooling on the cooling medium in the heat exchange assembly 122 after primary heat exchange cooling through a secondary cold head 1212; and using the cooling medium in the heat exchange assembly 122 after secondary heat exchange cooling to conduct heat transfer cooling to the magnet assembly 112, thereby achieving cooling of the magnet assembly 112.

[0096] In one embodiment, the primary cold head 1211 performs primary heat exchange cooling of the cooling medium in the heat exchange assembly 122 through thermal coupling between the first heat exchanger 1221 and the primary cold head 1211 in the heat exchange assembly 122; the secondary cold head 1212 performs secondary heat exchange cooling of the cooling medium in the heat exchange assembly 122 after primary heat exchange cooling through thermal coupling between the second heat exchanger 1222 and the secondary cold head 1212 in the heat exchange assembly 122. Of course, primary and secondary heat exchange cooling also include heat exchange between the cooling medium flowing in and flowing out of the heat exchanger. For example, the cooling medium entering the first heat exchanger 1221 along the outflow direction typically has a lower temperature than the cooling medium entering along the inflow direction, and heat exchange exists between the two cooling media in different directions.

[0097] In one embodiment, before the first-stage heat exchange cooling, the cooling medium before entering the first heat exchanger 1221 is pre-cooled using a third heat exchanger 1227. This three-stage cooling of the cooling medium reduces the cooling efficiency requirements of the cold head.

[0098] In one embodiment, a fourth heat exchanger 1228 is included before the secondary heat exchange cooling to pre-cool the cooling medium after the primary heat exchange cooling and before it enters the second heat exchanger 1222. This four-stage cooling of the cooling medium ensures that the cooled medium reaches a sufficient temperature after heat exchange cooling, guaranteeing the cooling efficiency of the magnet assembly 112. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0099] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A superconducting magnet device, characterized in that, include: Low-temperature holder with a storage space; A magnet assembly is disposed inside the cryogenic holder; as well as The cooling structure includes a refrigerator and a heat exchange assembly. The refrigerator has a primary cold head and a secondary cold head. The heat exchange assembly is heat-exchange connected to the primary cold head and the secondary cold head, and the heat exchange assembly after heat exchange is also thermally coupled to the magnet assembly. The power source provides power for the movement of the cooling medium, so that the cooling medium is circulated and transported through the heat exchange components and then flows back to the power source; The refrigeration unit includes a refrigeration inlet pipe, one end of which is connected to the output end of the power source, and the other end of which is connected to the primary cold head and the secondary cold head. The cryogenic holder further includes a radiation shielding layer and an outer container. The outer container is disposed outside the magnet assembly, and the radiation shielding layer is located between the outer container and the magnet assembly. The heat exchange assembly further includes a first connector that connects the primary cold head to the radiation shielding layer.

2. The superconducting magnet device according to claim 1, characterized in that, The heat exchange assembly includes a first heat exchanger and a second heat exchanger. The first heat exchanger is connected to the first-stage cold head for heat exchange, and the second heat exchanger is connected to the second-stage cold head for heat exchange.

3. The superconducting magnet device according to claim 2, characterized in that, The heat exchange assembly further includes a heat exchange inlet pipe and a heat exchange return pipe for supplying the cooling medium. One end of the heat exchange inlet pipe is connected to the output end of the power source, and the other end of the heat exchange inlet pipe is connected to the first heat exchanger and the second heat exchanger. One end of the heat exchange return pipe is connected to the input end of the power source, and the other end of the heat exchange return pipe is connected to the first heat exchanger and the second heat exchanger.

4. The superconducting magnet device according to claim 3, characterized in that, The refrigeration unit also includes a refrigeration return pipe, one end of which is connected to the input end of the power source, and the other end of which is connected to the primary cold head and the secondary cold head.

5. The superconducting magnet device according to claim 3, characterized in that, The heat exchange assembly also includes a cooling pipe, one end of which is connected to the heat exchange inlet pipe and the other end of which is connected to the heat exchange return pipe. The cooling pipe is arranged around the periphery of the magnet assembly.

6. The superconducting magnet device according to claim 3, characterized in that, The heat exchange assembly further includes a second connector that connects the second heat exchanger to the magnet assembly.

7. The superconducting magnet device according to any one of claims 2 to 6, characterized in that, The heat exchange assembly also includes a third heat exchanger, which is disposed at the input end of the first heat exchanger and is used to cool the cooling medium entering the first heat exchanger.

8. The superconducting magnet device according to any one of claims 2 to 6, characterized in that, The heat exchange assembly further includes a fourth heat exchanger, which is disposed at the input end of the second heat exchanger and is used to cool the cooling medium entering the second heat exchanger.

9. A magnetic resonance imaging device, characterized in that, The device includes a superconducting magnet device having a scanning aperture, the superconducting magnet device comprising: Low-temperature holder with a storage space; A magnet assembly is disposed inside the cryogenic holder; and The cooling structure includes a refrigerator and a heat exchange assembly. The refrigerator has a primary cold head and a secondary cold head. The heat exchange assembly is heat-exchange connected to the primary cold head and the secondary cold head, and the heat exchange assembly after heat exchange is also thermally coupled to the magnet assembly. The power source provides power for the movement of the cooling medium, so that the cooling medium is circulated and transported through the heat exchange components and then flows back to the power source; The refrigeration unit includes a refrigeration inlet pipe, one end of which is connected to the output end of the power source, and the other end of which is connected to the primary cold head and the secondary cold head. The cryogenic holder further includes a radiation shielding layer and an outer container. The outer container is disposed outside the magnet assembly, and the radiation shielding layer is located between the outer container and the magnet assembly. The heat exchange assembly further includes a first connector that connects the primary cold head to the radiation shielding layer.

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