Magnetic field generating apparatus and nuclear magnetic resonance apparatus

Abstract

To provide a magnetic field generating apparatus capable of reducing burden on an operator while reliably preventing an apparatus, a metal object and a precision apparatus attached to or owned by the operator from entering a range where strong magnetic field is generated, and a nuclear magnetic resonance apparatus including the magnetic field generating apparatus.SOLUTION: The magnetic field generating apparatus comprises a stay 14 composed of nonmagnetic materials, axially movable to a storage container 13 in which a superconductor 12 is stored, and respectively comprises: strong magnetic field protection members 16a-16c attached to the stay 14 after the superconductor 12 is magnetized and at least surrounding a space where the intensity of magnetic field generated by the superconductor 12 is first threshold or higher; and weak magnetic field protection members 17a-17c attached to the stay 14 outside the strong magnetic field protection members 16a-16c, and at least surrounding a space where the intensity of magnetic field generated by the superconductor 12 is equal to or higher than second threshold smaller than the first threshold.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a magnetic field generating device that generates a magnetic field, and a nuclear magnetic resonance apparatus that uses the magnetic field generated by the magnetic field generating device. [Background technology]

[0002] Various analytical techniques and imaging diagnostic techniques using nuclear magnetic resonance (NMR) have been put to practical use. Nuclear magnetic resonance is a phenomenon in which, when an atomic nucleus is exposed to a magnetic field and an electromagnetic wave is irradiated from the outside, the atomic nucleus absorbs a specific electromagnetic wave according to its respective chemical environment. Examples of nuclear magnetic resonance devices that use this nuclear magnetic resonance phenomenon include nuclear magnetic resonance analyzers (NMR analyzers) that use the nuclear magnetic resonance phenomenon to analyze the structure of a sample, and magnetic resonance imaging devices (MRI devices) that use the nuclear magnetic resonance phenomenon to create images of information inside a living body.

[0003] These nuclear magnetic resonance devices (hereafter referred to as NMR devices) are equipped with a magnetic field generator that generates a magnetic field as part of the device, and since the stronger the magnetic field strength generated, the higher the signal sensitivity and resolution, it is desirable for NMR devices to be equipped with a magnetic field generator that generates a strong magnetic field. One type of magnetic field generator that generates a strong magnetic field is a magnetic field generator that uses a superconducting bulk magnet (e.g., an oxide-based high-temperature superconductor) that generates a strong magnetic field through a magnetization process, and such superconductors that generate a strong magnetic field by magnetization have the advantage of being able to reduce the size of the device because they do not require current flow, as compared to conventional devices using superconducting coils.

[0004] However, while such a magnetic field generator equipped with a superconductor that generates a strong magnetic field by magnetization does not require current, it has a problem that the generation of a magnetic field cannot be switched on or off at will, and once magnetized, the state of generating a strong magnetic field is basically maintained for a long time even when not in use. Here, since the magnetic field generator generates a particularly strong magnetic field in a close distance from the superconductor that is the source (magnetic pole) of the magnetic field, there is a possibility that the magnetic field generator may attract metal objects worn or carried by workers during the exterior assembly process during transportation and installation, during regular maintenance, storage, etc., other than when in use, or cause malfunction of precision equipment. Therefore, it is desirable to protect the range of the strong magnetic field so that metal objects worn or carried by workers and precision equipment can be prevented from entering the range of the strong magnetic field from all directions until the above work is completed. Therefore, for example, JP-T-2006-513789 proposes a concept of covering the entire body of an NMR device with a packaging material made of a nonmagnetic material when storing or transporting the device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2006-513789 (Paragraph 0034) Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology of Patent Document 1 has a problem in that the NMR device needs to be packed in packaging materials every time it is stored or transported after use. On the other hand, when the NMR device is used, the packaging materials need to be removed, and it is difficult to use the device in its entirety without removing the packaging materials.

[0007] The present invention has been made to solve the above-mentioned problems in the conventional art, and aims to provide a magnetic field generating device and a nuclear magnetic resonance apparatus equipped with a magnetic field generating device which reliably prevents metal objects or precision instruments worn or carried by an operator from entering the area where a strong magnetic field is generated, while reducing the workload on the operator. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the magnetic field generating device of the present invention comprises a superconductor magnetized by a magnetizing device, a cylindrical storage container for storing the superconductor inside, a cylindrical portion that can be fitted into the magnetizing device and a flange portion extending radially from the cylindrical portion, a stay made of a non-magnetic material that surrounds the outer periphery of the storage container with the cylindrical portion and can move axially relative to the storage container in the surrounded state, a first protective cover that is attached to the flange portion after the superconductor is magnetized and surrounds at least a space in which the strength of the magnetic field generated by the superconductor is equal to or greater than a first threshold, and a second protective cover that is further attached to the outside of the first protective cover to the flange portion and surrounds at least a space in which the strength of the magnetic field generated by the superconductor is equal to or greater than a second threshold that is weaker than the first threshold.

[0009] Further, a nuclear magnetic resonance apparatus according to the present invention is a nuclear magnetic resonance apparatus including at least the above-mentioned magnetic field generating apparatus. Effect of the Invention

[0010] According to the magnetic field generating device of the present invention having the above-mentioned configuration, since the first protective cover and the second protective cover are provided around the magnetized superconductor, it is possible to reliably prevent the intrusion of metal objects or precision instruments worn or carried by the worker into the area where the strong magnetic field is generated. On the other hand, once the first protective cover and the second protective cover are attached after the superconductor is magnetized, there is no need to remove the first protective cover and the second protective cover until the superconductor is magnetized again, which reduces the workload of the worker.

[0011] Furthermore, according to the nuclear magnetic resonance apparatus of the present invention having the above-mentioned configuration, the magnetic field generating device of the nuclear magnetic resonance apparatus is provided with the first protective cover and the second protective cover around the magnetized superconductor, so that it is possible to reliably prevent the intrusion of metal objects or precision instruments worn or carried by the operator into the area where the strong magnetic field is generated. On the other hand, once the first protective cover and the second protective cover are attached after the superconductor is magnetized, there is no need to remove the first protective cover and the second protective cover until the superconductor is magnetized again, and the workload of the operator can be reduced. [Brief description of the drawings]

[0012] [Figure 1] 1 is an external view showing the entirety of an NMR analyzer according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an external view showing the entire NMR analyzer with the protective cover covering the outside of the apparatus removed. [Diagram 3] FIG. 2 is a cross-sectional view showing the NMR analyzer, particularly the periphery of the main body. [Figure 4] FIG. [Diagram 5] FIG. 5 is a cross-sectional view of the stay taken along line XX in FIG. 4. [Figure 6] FIG. 1 is a diagram showing the magnetization process of a superconductor performed using a magnetization device. [Figure 7] FIG. 4 is a schematic diagram showing the transition of the positional relationship between a magnetization device, a stay, and a container when magnetizing a superconductor. [Figure 8] 1 is a diagram showing a space surrounded by a strong magnetic field protection member and a weak magnetic field protection member. [Figure 9] FIG. 1 is a diagram showing a schematic configuration of an NMR analyzer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a detailed description will be given of specific embodiments of a magnetic field generating device and a nuclear magnetic resonance apparatus equipped with the magnetic field generating device according to the present invention with reference to the drawings. In the following, a nuclear magnetic resonance analyzer (hereinafter referred to as an NMR analyzer) that analyzes the structure of a sample by utilizing the nuclear magnetic resonance phenomenon will be given as an example of a nuclear magnetic resonance apparatus equipped with a magnetic field generating device.

[0014] First, a schematic configuration of an NMR analyzer 1 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is an external view showing the entire NMR analyzer 1 according to this embodiment, and Figure 2 is an external view showing the entire NMR analyzer 1 with protective covers (weak magnetic field protection members 17a to 17c described later) covering the outside of the apparatus removed.

[0015] 1 and 2, the NMR analyzer 1 according to this embodiment basically comprises a main body 2 having a sample container for accommodating a sample to be analyzed and a magnetic field generator for generating a static magnetic field, an external device 4 connected to the main body 2 through piping 3 and cables and equipped with a compressor for supplying a refrigerant for cooling a superconductor in the magnetic field generator and a pump for evacuating the inside of the main body 2, and a cart 5 on which the main body 2 and the external device 4 can be placed and moved together. However, the cart 5 is not essential for the NMR analyzer 1 of this embodiment, and the main body 2 and the external device 4 may be installed on the floor.

[0016] First, a description will be given of the main body 2 of the NMR analyzer 1. Fig. 3 is a cross-sectional view showing the NMR analyzer 1, particularly the main body 2 and its periphery. As shown in FIG. 3, the main body 2 includes a sample container 11 for accommodating a sample to be analyzed therein, a cylindrical superconductor 12 arranged around the sample container 11, a similarly cylindrical container 13 for accommodating the superconductor 12 therein, a disk-shaped stay (upper fixing member) 14 arranged around the container 13, a vacuum insulation container 15 for insulating the superconductor 12 by creating a vacuum inside the container 13, strong magnetic field protection members (first protection covers) 16a to 16c that are protection covers arranged outside the container 13 to surround a space of a strong magnetic field in which the strength of the magnetic field generated by the superconductor 12 is equal to or greater than a first threshold value, and a protective cover for the superconductor 12 arranged further outside the strong magnetic field protection members 16a to 16c. The weak magnetic field protection member (second protection cover) 17a-17c is a protection cover arranged to surround a space of a weak magnetic field where the strength of the magnetic field generated by the external device 4 is equal to or greater than a second threshold value, a refrigerator 18 that expands a compressed refrigerant (e.g., He gas, Ne gas, H gas, N gas, or a liquefied version of these) supplied from an external device 4 to generate cold, a cold head 19 for transmitting the cold generated in the refrigerator 18 to the superconductor 12, a disk-shaped central fixing member 20 and a lower fixing member 21 that are arranged around the container 13 below the stay 14 and fix the weak magnetic field protection member 17a-17c together with the stay 14, and a fixed support 22 for supporting the main body 2. The stay 14 is held at a predetermined position (height) from the lower end of the container 13 by the fixed support 22. In this embodiment, the strong magnetic field protection member 16a-16c and the weak magnetic field protection member 17a-17c are divided into three, but they may be an integrated protective cover. As shown in FIG. 1, the side surface of the main body 2 is provided with a window 23 formed of a transparent member, which allows an operator to visually check the inside of the main body 2.

[0017] Although not explained further, the main body 2 also includes various devices and components necessary for analyzing samples in the NMR analysis device 1, such as a high-frequency generator that produces electromagnetic waves, a coil that irradiates the sample container 11 with electromagnetic waves and through which a nuclear magnetic resonance signal (NMR signal) from the sample container 11 flows, a detection unit that amplifies and detects the nuclear magnetic resonance signal that flows through the coil, and a control unit that controls these (all of these are collectively referred to as a probe).

[0018] Furthermore, among the various components contained in the main body 2, the superconductor 12, the container 13, the stays 14, the vacuum insulation container 15, the strong magnetic field protection members 16a to 16c, the weak magnetic field protection members 17a to 17c, the refrigerator 18, and the cold head 19 are included in the magnetic field generating device.

[0019] Each of the components of the main body 2 will be described below in order. The sample container 11 is, for example, a sealed cylindrical container, and contains various samples such as organic compounds, inorganic compounds, and biological materials in various fields such as the pharmaceutical field, the biotechnology field, and the material field when the NMR analyzer 1 is used. The NMR analyzer 1 according to this embodiment irradiates the sample container 11 placed in the static magnetic field generated by the superconductor 12 with a pulsed electromagnetic wave using a probe to excite nuclear magnetic resonance, and detects a nuclear magnetic resonance signal generated by the nuclear magnetic resonance, thereby analyzing the crystal structure of the sample in the sample container 11. Although not shown in the figure, the NMR analyzer 1 is also connected to a monitor for displaying the analysis results, a storage device for storing the analysis results, a keyboard and a mouse for an operator to operate the device.

[0020] On the other hand, the superconductor 12 corresponds to a magnetic field source (magnetic pole) in the NMR analyzer 1, and generates a static magnetic field for analyzing a sample. For the purpose of being able to generate a strong static magnetic field with excellent stability and enabling the device to be made smaller, a superconducting bulk magnet, particularly a high-temperature superconducting bulk magnet with a relatively high superconducting transition temperature (critical temperature), is used as the superconductor 12. For example, a high-temperature oxide superconductor such as RE-Ba-Cu-O (RE is a rare earth element including Y) based superconductor is preferable. However, the superconductor 12 is not limited to the above example, and may be a Nd-based, Sm-based, or Gd-based superconducting bulk magnet. In addition, a magnet other than a high-temperature superconducting bulk magnet may be used as long as it can be kept below the superconducting transition temperature.

[0021] The superconductor 12 according to this embodiment is formed in a cylindrical shape so as to surround the sample container 11 as shown in FIG. 3, and is placed in a container 13 also having a cylindrical shape. In particular, in this embodiment, the superconductor 12 is formed by stacking a plurality of (e.g., 3 to 10) cylindrical superconducting bulk magnets along the axial direction. However, the superconductor 12 may be formed by a single superconducting bulk magnet instead of a plurality of magnets. In addition, the superconductor 12 is thermally connected to a cold head 19 as described later, and cold generated by a refrigerator 18 can be transferred to the superconductor 12.

[0022] Furthermore, the above-mentioned superconducting bulk magnet does not require energization to generate a magnetic field, but it is necessary to carry out the following magnetization steps (1) to (3) in advance. (1) Magnetic field application process A magnetic field is applied to the superconductor by an external magnetic field generating device (hereinafter referred to as a magnetizing device) so that a magnetic field is generated in the inner space of the superconductor 12 at a temperature higher than the superconducting transition temperature (critical temperature) of the superconductor 12, in which magnetic flux passes axially. (2) Cooling process in magnetic field The superconductor 12 to which the magnetic field has been applied by the magnetizing device as described above is cooled to a temperature T0 that is equal to or lower than the superconducting transition temperature. Specifically, the refrigerator 18 is operated while a magnetic field is being applied to the superconductor 12 by the operation of the magnetizing device. This causes the refrigerator 18 to generate cold heat, which is transferred via the cold head 19 to the superconductor 12 that is thermally connected to the cold head 19. This causes the superconductor 12 to be cooled to a temperature T0 that is equal to or lower than the superconducting transition temperature. Thereafter, the cooled state of the superconductor 12 is maintained. (3) Demagnetization process While maintaining the temperature of the superconductor 12 at temperature T0, the operation of the magnetizing device is stopped. This removes the magnetic field applied to the superconductor 12, which has been cooled to a temperature below the superconducting transition temperature (i.e., put into a superconducting state). Then, in response to the change in magnetic field strength caused by the removal of the applied magnetic field, a superconducting current is induced in the superconductor 12 so as to restore the state of the magnetic field. The superconducting current is a circular current that flows around the central axis of the superconductor 12 in a plane perpendicular to the central axis of the superconductor 12. A magnetic field is generated by the superconducting current thus induced flowing through the superconductor 12. That is, the superconductor 12 is magnetized. The magnetic field generated by magnetizing the superconductor 12 is basically the same as the applied magnetic field generated by the operation of the magnetizing device. That is, when the superconducting current flows through the superconductor 12, the superconductor 12 captures the applied magnetic field generated by the operation of the magnetizing device. By trapping the applied magnetic field, the superconductor 12 forms a magnetic field (trapped magnetic field) in which magnetic flux passes in the axial direction within the inner space of the superconductor 12. Since the sample container 11 is located within the inner space of the superconductor 12 where the trapped magnetic field is generated, a sample can be placed within a static magnetic field, and as described above, the sample can be analyzed by applying an electromagnetic wave to the sample placed within the strong static magnetic field.

[0023] Once the magnetization steps (1) to (3) have been performed, it is possible to maintain the state in which a strong magnetic field is generated (superconducting characteristics) for a long period of time by holding the magnetized superconductor 12 at a temperature below the superconducting transition temperature using the refrigerator 18 and cold head 19. Even if the strong magnetic field is subsequently lost due to a temperature rise or other reasons, it is possible to restore the state in which a strong magnetic field is generated by performing the magnetization steps again.

[0024] The container 13 has a long cylindrical shape as shown in FIG. 3, and contains the superconductor 12 around the sample container 11, particularly around the top. A cold head 19 and a refrigerator 18, which will be described later, are also contained below the superconductor 12. A stay 14, a middle fixing member 20, and a lower fixing member 21 are disposed around the container 13. The inside of the container 13 is kept in a vacuum state (insulated state) by a vacuum insulation container 15, which will be described later. The container 13 has an outer wall covering the outer peripheral surface of the superconductor 12, a ring-shaped lid portion extending from the upper end of the outer wall radially inwardly of the superconductor 12 to cover the upper end surface of the superconductor 12, and a ring-shaped bottom portion extending from the lower end of the outer wall radially inwardly of the superconductor 12 to cover the lower end surface of the superconductor 12. The superconductor 12 inside is held by being surrounded by the outer wall, the lid portion, and the bottom portion. The bottom portion is thermally connected to the cold head 19.

[0025] Further, the stay 14 has a disk shape and is made of a non-magnetic material (e.g., a resin material, titanium, aluminum, etc.), and is disposed around the container 13. The stay 14 has a large number of screw holes and the like formed therein, and corresponds to a fixing member used to fix the strong magnetic field protection members 16a to 16c and the weak magnetic field protection members 17a to 17c, which will be described later, to the main body 2. Here, FIG. 4 is an external view showing the appearance of the stay 14.

[0026] As shown in FIG. 4, the stay 14 includes a cylindrical portion 25 that surrounds the outer wall portion, which is the outer periphery of the storage container 13, and a flange portion 26 that extends radially from the lower end of the cylindrical portion 25. The cylindrical portion 25 has a cylindrical shape corresponding to the storage container 13, and is disposed at a predetermined position (height) from the lower end of the storage container 13 so as to surround the outer wall portion, which is the outer periphery of the storage container 13. The inner diameter of the cylindrical portion 25 is a length that corresponds to the outer diameter of the storage container 13 (the inner diameter of the cylindrical portion 25 is slightly larger than the outer diameter of the storage container 13, and is a length that allows the storage container 13 to pass through the inside of the cylindrical portion 25 and allows the relative position to be fixed when no load is applied). The stay 14 and the storage container 13 are assembled, for example, by an interference fit with the cylindrical portion 25. However, before assembly, the stay 14 can be moved axially relative to the storage container 13 by applying a load (the height position can be adjusted), and the axial position of the stay 14 (the position from the bottom end of the storage container 13) is finally determined by the worker assembling the fixed support 22.

[0027] As shown in Fig. 4, the flange portion 26 has a number of screw holes 27 formed in the axial direction (vertical direction). Furthermore, screw holes 28 are formed in the outer peripheral surface of the flange portion 26 in the radial direction. Here, as shown in Fig. 3, the axial screw holes 27 are used to fix the strong magnetic field protection members 16a to 16c. Specifically, the strong magnetic field protection member 16a and the strong magnetic field protection member 16b are fixed to the upper side of the stay 14 by screws (however, the strong magnetic field protection member 16a is not directly fixed to the stay 14 but is fixed via the strong magnetic field protection member 16b), and the strong magnetic field protection member 16c is fixed to the lower side of the stay 14 by screws.

[0028] 3, the radial screw holes 28 are used to fix the weak magnetic field protection members 17a to 17c. Specifically, the weak magnetic field protection member 17a and the weak magnetic field protection member 17b are fixed to the upper side of the stay 14 by screws (however, the weak magnetic field protection member 17a is not directly fixed to the stay 14, but is fitted onto the weak magnetic field protection member 17b as a cover), and the weak magnetic field protection member 17c is fixed to the lower side of the stay 14 by screws. The weak magnetic field protection member 17c is also fixed to the middle fixing member 20 and the lower fixing member 21, which are located below the stay 14, by screws.

[0029] On the other hand, as shown in Fig. 4, the flange portion 26 has a gear shape when viewed from above, and has multiple gaps 29 between the teeth. These gaps 29 can be used as passageways for cables and piping that travel between the upper and lower parts of the stay 14 inside the main body portion 2. Since multiple gaps 29 exist in the radial direction, the gap 29 through which the cables and piping are to pass can be freely selected depending on the position of the cables and piping. As a result, as shown in Figs. 2 and 3, it is also possible to take out the cables and piping connected to the upper part of the storage container 13 from the lower end of the main body portion 2. Note that the flange portion 26 may have a shape other than a gear shape as long as there are gaps 29 for passing the cables and piping.

[0030] 5 is a cross-sectional view of the stay 14 taken along line XX in FIG. 4. As shown in FIG. 5, the stay 14 has the inside surface of the cylindrical portion 25, particularly the lower end side 25a, chamfered (tapered). This chamfering makes it possible to easily mount the stay 14 on the NMR analyzer 1, as described below. In the example shown in FIG. 5, the chamfering is performed in a straight line, but the chamfering may be performed in a curved line. Also, the chamfering is basically performed only on the lower end side corresponding to the insertion direction of the NMR analyzer 1 when mounting the stay 14 on the NMR analyzer 1, but the upper end side may also be chamfered.

[0031] Next, the process of mounting the stay 14 on the NMR analyzer 1 will be described. Here, in the NMR analyzer 1 of this embodiment, the stay 14 is not provided in advance in the NMR analyzer 1, but is adapted to be attached to the NMR analyzer 1 during the magnetization process of the superconductor 12 described above.

[0032] Here, the magnetization of the superconductor 12 includes the above-mentioned steps (1) to (3), and is performed by applying a magnetic field using an external magnetic field generator (magnetization device). The magnetization device 31 has an insertion section 32 on the bottom surface as shown in FIG. 6, and specifically, the above-mentioned steps (1) to (3) are performed by inserting the container 13, which contains the superconductor 12 before magnetization, into the insertion section 32. Note that, as shown in FIG. 6, when the magnetization step is performed, the main body 2 is in a state where the stay 14, the vacuum insulation container 15, the strong magnetic field protection members 16a to 16c, and the weak magnetic field protection members 17a to 17c are removed, and the container 13 is exposed. On the other hand, the refrigerator 18 and the cold head 19 are provided, and the superconductor 12 can be cooled.

[0033] 7 is a schematic diagram showing the transition of the positional relationship among the magnetizing device 31, the stay 14, and the container 13 when magnetizing the superconductor 12. As shown in FIG. 7, the container 13 is inserted into the insertion part 32 of the magnetizing device 31, and the above-mentioned "(1) magnetic field application step", "(2) cooling step in a magnetic field step", and "(3) demagnetization step" are performed to magnetize the superconductor 12. Finally, the magnetic field applied from the outside is captured by the magnetizing device 31, and after the magnetization is completed, the container 13 is pulled out from the insertion part 32 of the magnetizing device 31. The above-mentioned insertion and pulling out may be performed by moving the magnetizing device 31 side up and down, or may be performed by moving the container 13 side up and down.

[0034] 7, the stay 14 is arranged with the cylindrical portion 25 fitted into the insertion portion 32 of the magnetization device 31 at a stage before magnetizing the superconductor 12. That is, an operator fits the stay 14 into the insertion portion 32 in advance when performing the magnetization process. The outer diameter of the cylindrical portion 25 of the stay 14 has a length corresponding to the inner diameter of the insertion portion 32 (the outer diameter of the cylindrical portion 25 is slightly smaller than the inner diameter of the insertion portion 32, and has a length that allows it to be kept in place when inserted into the insertion portion 32).

[0035] When the storage container 13 is inserted into the insertion portion 32 to magnetize the superconductor 12, the storage container 13 is also inserted into the cylindrical portion 25. As described above, the inner diameter of the cylindrical portion 25 of the stay 14 has a length corresponding to the outer diameter of the storage container 13, and further, the inner surface of the cylindrical portion 25 of the stay 14 is chamfered (FIG. 5), so that the storage container 13 can be easily inserted into the cylindrical portion 25. Furthermore, since the position of the stay 14 relative to the insertion portion 32 is fixed during insertion, the position of the stay 14 relative to the storage container 13 also changes depending on the amount of the storage container 13 inserted into the insertion portion 32. That is, when the storage container 13 is shallowly inserted into the insertion portion 32, the stay 14 is located above the storage container 13, and when the storage container 13 is deeply inserted into the insertion portion 32, the stay 14 is located below the storage container 13. In addition, when the storage container 13 is inserted into the insertion portion 32, the position of the storage container 13 is guided by the stay 14, so that the storage container 13 is maintained coaxial with the insertion portion 32 and it is also possible to prevent the storage container 13 from coming into contact with the inside of the insertion portion 32.

[0036] Then, when the magnetization process is completed and the storage container 13 is pulled out from the insertion part 32 of the magnetization device 31, the stay 14 is separated from the magnetization device 31 together with the storage container 13 while being disposed on the outer periphery of the storage container 13, as shown in FIG. 7. Since the fitting between the storage container 13 and the cylindrical part 25 is stronger than the fitting between the insertion part 32 and the cylindrical part 25, the stay 14 is separated from the magnetization device 31 together with the storage container 13 without remaining in the magnetization device 31. As a result, the stay 14 is attached to the NMR analyzer 1. It is also possible to adjust the position of the attached stay 14 by the amount of insertion of the storage container 13 into the insertion part 32. In addition, the position of the stay 14 can be adjusted by applying a load even after the storage container 13 is pulled out from the insertion part 32, and it is finally positioned by assembling the fixed support 22.

[0037] In the NMR analyzer 1 of this embodiment, when the magnetization process of the superconductor 12 is performed as described above, the stay 14 is also attached at the same time, so the worker does not need to manually attach the stay 14 after magnetization. Since a strong magnetic field is generated around the superconductor 12 after magnetization, if the stay 14 is manually attached to the container 13, there is a possibility that it may attract metal objects held by the worker or cause malfunction of precision equipment, but this embodiment can eliminate such a possibility.

[0038] Then, after magnetization of the superconductor 12 is completed and the stay 14 is also attached, the worker fixes the vacuum insulation container 15, the strong magnetic field protection members 16a to 16c, and the weak magnetic field protection members 17a to 17c to the screw holes 27, 28 formed in the flange portion 26. The fixing support 22 is also assembled. As a result, the main body 2 has an appearance as shown in FIG. 1.

[0039] On the other hand, the vacuum insulation container 15 is disposed inside the storage container 13. The above-mentioned superconductor 12 is disposed further inside the vacuum insulation container 15. The vacuum insulation container 15 has an internal space, which is in a vacuum state. By making the internal space in a vacuum state, it is possible to insulate the superconductor 12 disposed inside.

[0040] The strong magnetic field protection members 16a to 16c are made of a non-magnetic material (e.g., resin material, titanium, aluminum, etc.) and are protective covers arranged to surround a space of a strong magnetic field where the strength of the magnetic field generated by the superconductor 12 is equal to or greater than a first threshold outside the container 13. Here, the first threshold is, for example, 500 Gauss. The space of a strong magnetic field equal to or greater than the first threshold corresponds to a space where it is necessary to prevent magnetic bodies from approaching the superconductor 12. As shown in FIG. 8, the strong magnetic field protection members 16a to 16c surround the space of a strong magnetic field equal to or greater than the first threshold, thereby reliably preventing the intrusion of metal objects worn or carried by an operator into the space. Note that the strong magnetic field protection members 16a to 16c may surround a larger area than the space as long as they can at least surround the space of a strong magnetic field where the strength of the magnetic field generated by the superconductor 12 is equal to or greater than the first threshold. However, it is preferable to make the size as small as possible within a range that satisfies the condition of surrounding the space of a strong magnetic field where the strength of the magnetic field is equal to or greater than the first threshold in order to reduce the size of the device.

[0041] Similarly, the weak magnetic field protection members 17a-17c are made of a non-magnetic material (e.g., resin material, titanium, aluminum, etc.) and are protective covers arranged outside the strong magnetic field protection members 16a-16c so as to surround a weak magnetic field space where the strength of the magnetic field generated by the superconductor 12 is equal to or greater than a second threshold. Here, the second threshold is, for example, 250 Gauss. The weak magnetic field space equal to or greater than the second threshold corresponds to a space where it is necessary to prevent precision equipment from approaching the superconductor 12. By surrounding the weak magnetic field space equal to or greater than the second threshold with the weak magnetic field protection members 17a-17c as shown in FIG. 8, it becomes possible to reliably prevent precision equipment worn or carried by an operator from entering the range. In addition, the weak magnetic field protection members 17a to 17c may surround a larger area than the space as long as they can surround at least the space of the weak magnetic field where the strength of the magnetic field generated by the superconductor 12 is equal to or greater than the second threshold value, but in order to reduce the size of the device, it is preferable to make the size as small as possible within the range that satisfies the condition of surrounding the space of the strong magnetic field where the strength of the magnetic field is equal to or greater than the second threshold value. As a result, in this embodiment, the main body 2 has a longer diameter (inverted triangle shape) at the top than at the bottom as shown in FIG. 1.

[0042] Furthermore, in this embodiment, after magnetizing the superconductor 12, the strong magnetic field protection members 16a to 16c and the weak magnetic field protection members 17a to 17c are attached to the stay 14, and thereafter, the strong magnetic field protection members 16a to 16c and the weak magnetic field protection members 17a to 17c are basically always attached until it is necessary to magnetize the superconductor 12 again (however, the weak magnetic field protection member 17a may be removed when setting the sample in the sample container 11). Therefore, not only when the NMR analyzer 1 is in use, but also during the external assembly process during transportation and installation, during regular maintenance, storage, etc., it is possible to prevent metal objects and precision instruments worn and carried by operators from entering the range of a magnetic field above the first threshold value or above the second threshold value from all directions until the completion of these operations.

[0043] On the other hand, refrigerator 18 is a device located below container 13, which generates cold by expanding a compressed refrigerant (e.g., He gas, Ne gas, H gas, N gas, or liquefied versions of these) supplied from external device 4. The type of refrigerator is not limited, but it is preferable that it is as small as possible and is a device that can generate cold enough to cool superconductor 12 to a temperature below the superconducting transition temperature (critical temperature). Examples of such refrigerators include GM refrigerators, Stirling refrigerators, and pulse tube refrigerators. One example is a pulse tube refrigerator, which generates cold by generating periodic pressure oscillations in a pulse tube and expanding and contracting a so-called gas piston in the pulse tube.

[0044] On the other hand, one end of the cold head 19 is thermally connected to the cold generating portion of the refrigerator 18 and the other end is thermally connected to the superconductor 12, and transfers the cold generated in the refrigerator 18 to the superconductor 12. The cold head 19 is made of a non-magnetic material (e.g., copper) that has high thermal conductivity. A vacuum state is maintained around the refrigerator 18 and the cold head 19 to insulate them.

[0045] Furthermore, the window 23 is disposed on the side of the main body part, and is formed of, for example, a transparent member so that an operator can visually check the inside of the main body part 2. The window 23 may have, for example, a hinge or the like, and may have a structure that allows it to be opened and closed by an operator. If the probe installed around the container 13 inside the main body part 2 can be adjusted (for example, the position of the coil relative to the superconductor 12) by opening the window 23, the task of removing the weak magnetic field protection members 17a to 17c for adjusting the probe is not required, and convenience is further improved.

[0046] Next, returning to Fig. 1, the external device 4 in the NMR analysis device 1 will be described. The external device 4 is connected to the above-mentioned main body 2 through the piping 3 and cables, and includes a compressor for supplying a refrigerant for cooling the superconductor 12, a pump for evacuating the inside of the main body 2, and the like. For example, a compressed refrigerant (e.g., He gas, Ne gas, H gas, N gas, or liquefied versions of these) is supplied from the external device 4, and the supplied refrigerant is expanded in the refrigerator 18 of the main body 2 to generate cold heat. In this embodiment, the main body 2 and the external device 4 are separate entities, but the external device 4 may be arranged inside the main body 2.

[0047] Finally, the dolly 5 of the NMR analyzer 1 will be described with reference to FIG. 1. The dolly 5 has a base 41 on which the main body 2 and the external device 4 are placed, wheels 42 attached to the underside of the base 41, and a handle 43 to be held by an operator. For example, an operator can hold the handle 43 and apply a load to easily move the main body 2 and the external device 4 to any position. In particular, the NMR analyzer 1 of this embodiment is smaller and lighter than conventional devices, so that it can be easily moved by human force. In addition, the main body 2 and the external device 4 are fixed to the base 41 by a fixing means (for example, a bolt, etc.) not shown, and the main body 2 and the external device 4 basically operate while placed on the dolly 5, and are stored while placed on the dolly 5 after the operation is completed. In addition, the wheels 42 are also equipped with a locking mechanism, and it is also possible to fix the position so that they do not move during the operation of the NMR analyzer 1.

[0048] Next, a brief description will be given of the control configuration of the NMR analyzer 1 having the above-mentioned configuration.

[0049] The NMR analysis apparatus 1 includes a magnetic field generator 51 for generating a magnetic field including the superconductor 12 and the refrigerator 18 described above, a detection coil 52, and an analysis means 53. The detection coil 52 is disposed within the inner circumferential space of the superconductor 12, and a sample to be analyzed is placed on the inner circumferential side of the detection coil 52. A shim coil 54 is disposed on the outer circumferential side of the detection coil 52. The analysis means 53 further includes a high frequency generator 61, a pulse programmer (transmitter) 62, a high frequency amplifier 63, a preamplifier (signal amplifier) ​​64, a phase detector (receiver) 65, an analog-to-digital (A / D) converter 66, and a control unit 67.

[0050] When the magnetic field generator 51 is in operation, a trapped magnetic field is formed in the inner space of the superconductor 12 as described above. Next, the trapped magnetic field is adjusted by the shim coil 54 to enhance the uniformity of the magnetic field strength of the trapped magnetic field. At this time, the trapped magnetic field is adjusted by the shim coil 54 so that the uniformity of the magnetic field strength in the space is 1 ppm or less. Then, after the uniformity of the magnetic field strength is enhanced, a sample is placed in the sample container 11 in the inner space of the superconductor 12. In this state, the high frequency generator 61 is operated. Then, a high frequency pulse generated by the high frequency generator 61 is applied to the detection coil 52 via the pulse programmer 62 and the high frequency amplifier 63, and the sample is irradiated with a pulse electromagnetic wave. When the sample placed in the magnetic field is irradiated with an electromagnetic wave, a nuclear magnetic resonance occurs, and a minute current flows in the detection coil 52 located around the sample. A signal (NMR signal) representing this minute current is transferred to the control unit 67 via the preamplifier 64, phase detector 65, and A / D converter 66. The control unit 67 calculates an NMR spectrum based on the received NMR signal, and the molecular structure of the sample is analyzed from the obtained NMR spectrum.

[0051] As described above in detail, the magnetic field generator 51 and the NMR analyzer 1 according to this embodiment include a cylindrical portion 25 that can be fitted into the magnetizing device 31, a flange portion 26 that extends radially from the cylindrical portion 25, and a stay 14 made of a non-magnetic material that surrounds the outer periphery of the storage container 13 with the cylindrical portion and can move axially relative to the storage container 13 while surrounded by the cylindrical portion. The stay 14 further includes strong magnetic field protection members 16a to 16c that are attached to the flange portion 26 after the superconductor 12 is magnetized and surround at least a space in which the strength of the magnetic field generated by the superconductor 12 is equal to or greater than a first threshold value, and weak magnetic field protection members 17a to 17c that are further attached to the outside of the strong magnetic field protection members 16a to 16c with respect to the flange portion 26 and surround at least a space in which the strength of the magnetic field generated by the superconductor 12 is equal to or greater than a second threshold value that is weaker than the first threshold value. This makes it possible to reliably prevent metal objects and precision instruments worn or carried by an operator from entering the area in which a strong magnetic field is generated. On the other hand, once the strong magnetic field protection members 16a-16c and the weak magnetic field protection members 17a-17c are attached after the superconductor is magnetized, there is no need to remove the strong magnetic field protection members 16a-16c and the weak magnetic field protection members 17a-17c until the superconductor is magnetized again, which also reduces the workload of the workers. In addition, the superconductor 12 is magnetized by capturing the magnetic field applied from the outside by the magnetizing device 31 while cooled to a temperature below the superconducting transition temperature, so no current is required compared to conventional superconducting coils, making it possible to reduce the size and weight of the device. Also, it becomes possible to generate a strong static magnetic field with excellent stability. Moreover, the magnetization of the superconductor 12 is performed by inserting the container 13 containing the unmagnetized superconductor 12 inside into the insertion portion 32 of the magnetization device 31, and the stay 14 is arranged with the cylindrical portion 25 fitted into the insertion portion 32 of the magnetization device 31 at the stage before magnetizing the superconductor 12, and when the container 13 is inserted into the insertion portion 32 to magnetize the superconductor 12, the container 13 is also inserted into the cylindrical portion 25, and when the container 13 is removed from the insertion portion 32 after magnetization, the stay 14 leaves the magnetization device 31 together with the container 13 in a state of being arranged on the outer periphery of the container 13. That is, when the magnetization process of the superconductor 12 is performed, the stay 14 is also attached at the same time, so that the worker does not need to manually attach the stay 14 after magnetization. Furthermore, since a strong magnetic field is generated around the superconductor 12 after magnetization, if the stay 14 is manually attached to the container 13, there is a possibility that it may attract metal objects held by the worker or cause malfunction of precision equipment; however, this embodiment can eliminate such a possibility.

[0052] Incidentally, the present invention is not limited to the above-described embodiment, and it is needless to say that various improvements and modifications are possible without departing from the spirit and scope of the present invention. For example, in this embodiment, the strong magnetic field protection members 16a-16c surround the space around the superconductor 12 with a strong magnetic field of 500 Gauss or more, and the weak magnetic field protection members 17a-17c surround the space around the superconductor 12 with a weak magnetic field of 250 Gauss or more, but the magnetic field strength of the surrounded space can be changed as appropriate. Furthermore, the shapes of the strong magnetic field protection members 16a-16c and the weak magnetic field protection members 17a-17c are not limited to those shown in Figs.

[0053] 4, the stay 14 may be appropriately modified in shape as long as it can fix the strong magnetic field protection members 16a to 16c and the weak magnetic field protection members 17a to 17c. The fixing method is not limited to screws.

[0054] In addition, in the present embodiment, a nuclear magnetic resonance analysis device that uses the nuclear magnetic resonance phenomenon to analyze the structure of a sample has been given as an example of a nuclear magnetic resonance device equipped with a magnetic field generating device, but the present invention can also be applied to a magnetic resonance imaging device (MRI device) that uses the nuclear magnetic resonance phenomenon to create an image of internal information within a living body. [Explanation of symbols]

[0055] 1...NMR analysis apparatus (nuclear magnetic resonance apparatus), 2...main body, 4...external device, 11...sample container, 12...superconductor, 13...container, 14...stay, 15...vacuum insulation container, 16a to 16c...strong magnetic field protection member (first protective cover), 17a to 17c...weak magnetic field protection member (second protective cover), 18...refrigerating machine, 19...cold head, 25...cylindrical portion, 26...flange portion, 31...magnetizing device, 32...insertion portion, 51...magnetic field generating device

Claims

1. a superconductor magnetized by a magnetizing device; a cylindrical container for accommodating the superconductor therein; a stay made of a non-magnetic material, the stay including a cylindrical portion that can be fitted into the magnetizing device and a flange portion that extends in a radial direction from the cylindrical portion, the stay surrounding an outer periphery of the container with the cylindrical portion and movable in an axial direction relative to the container while being surrounded by the cylindrical portion; a first protective cover that is attached to the flange portion after the superconductor is magnetized and that encloses at least a space in which the strength of the magnetic field generated by the superconductor is equal to or greater than a first threshold value; A magnetic field generating device comprising: a second protective cover further attached to the outside of the first protective cover relative to the flange portion, enclosing at least a space in which the strength of the magnetic field generated by the superconductor is equal to or greater than a second threshold value that is weaker than the first threshold value.

2. 2. The magnetic field generating device according to claim 1, wherein the superconductor is magnetized by capturing an externally applied magnetic field by the magnetizing device in a state where the superconductor is cooled to a temperature below its superconducting transition temperature.

3. the magnetization of the superconductor is performed by inserting the container containing the superconductor before magnetization into an insertion portion of the magnetization device; The stay is the cylindrical portion is disposed in a fitted state in the insertion portion of the magnetization device before the magnetization of the superconductor is performed, When the container is inserted into the insertion portion to magnetize the superconductor, the container is also inserted into the cylindrical portion, The magnetic field generating device according to claim 2 , wherein when the container is removed from the insertion portion after magnetization, the magnetizing device separates from the container together with the container in a state of being disposed on the outer periphery of the container.

4. A nuclear magnetic resonance apparatus comprising the magnetic field generating device according to any one of claims 1 to 3.

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