KR100783646B1 - Superconductive magnet apparatus cooled by refrigerating machine - Google Patents

Abstract

Provided is a superconducting magnet device for generating a horizontal magnetic field, which can be easily operated and can be miniaturized.

The superconducting magnet device includes a double-cylindrical vacuum vessel 10 having an air space in the center, two pairs of superconducting coils 11a to 11d arranged vertically in the vacuum vessel to generate a horizontal magnetic field, and each superconducting member. And a cryocooler for cooling the coil. The two pairs of superconducting coils, each pair of superconducting coils face each other with an air space therebetween, and a line segment (L1) connecting the center of one pair of superconducting coils and the center of the other pair of superconducting coils. It arrange | positioned adjacently so that arrangement | positioning angle (theta) between (L2) might be 40 degrees <= (theta) <= 90 degrees.

Superconducting Magnetic Device, Superconducting Coil, Magnetic Field, Vacuum Container

Description

Superconductive magnet apparatus cooled by refrigerating machine

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the outline | summary of the refrigerator-cooling type superconducting magnet apparatus which concerns on this invention.

2 is a cross-sectional view of a refrigerator cooling superconducting magnet device according to an embodiment of the present invention.

3 is a longitudinal cross-sectional view taken along the line A-A 'of FIG.

FIG. 4 is a top view of the apparatus of FIG. 2 with respect to only one cryogenic chiller and its peripheral components. FIG.

5 is a cross-sectional view illustrating a mounting structure of the refrigerator in FIG. 2.

6 is a cross-sectional view for explaining the vertical load supporting body and the horizontal load supporting body in the present invention.

Fig. 7 is a sectional view showing the mounting structure of the current lead in the present invention.

8 is an explanatory diagram for explaining a relationship between an arrangement angle and a coil radius.

9 is a graph showing a relationship between a generated magnetic field, a coil radius, and an arrangement angle.

Explanation of symbols on the main parts of the drawings

10: vacuum container                 

10-1: insertion hole

10-2: Flange

11a to 11d: superconducting coil

12a-12d: cryogenic freezer

12-1: 1st stage freezing stage

12-2: 2nd stage freezing stage

12-11: First stage cold head

12-21: 2nd stage cold head

13: structure

13-1: Connection

14: multi-layer plate heat transfer member

15: heat radiation shield

16: vertical load bearing

17: horizontal load bearing

23: sleeve

23-1: front end heating member

23-2: intermediate heat transfer member

26: magnetic shield

27: current lead

The present invention relates to a refrigerator cooling type superconducting magnet device, and more particularly to a refrigerator cooling type superconducting magnet device suitable for a magnetic field generating device for imparting a magnetic field to molten silicon in a single crystal growth device for producing a single crystal semiconductor from molten silicon. .

In the production of silicon single crystals, the Czochralski method (CZ method) is known in which polycrystalline silicon is melted and crystal grown through seed crystals for single crystal growth. Since molten silicon melts in a crucible, the quality of the single crystal produced by tropical flow may be degraded in some cases. Therefore, a method of suppressing convection by electromagnetic braking by applying a magnetic field to molten silicon for the purpose of improving the quality of the produced single crystal or the like is known. This method is called magnetic field recognition Czochralski method (MCZ method). As the application direction of the magnetic field, there are three types of applying a vertical magnetic field in the vertical direction, a horizontal magnetic field in the horizontal direction, and a caspe magnetic field to the liquid surface of the molten silicon.

On the other hand, phase conductive magnets and superconducting magnets are used as the magnetic field applying means. In addition, for example, as a coil shape generating a horizontal magnetic field, a split coil or a pair of saddle coils having two solenoid coils arranged vertically at intervals are used.

However, when a phase conductive magnet is used as the magnetic field applying means, there are the following problems.                         

• Since the use of the iron core is indispensable, the weight of the magnet becomes heavy.

ㆍ Expand electric power and coolant.

ㆍ There is a limit to the magnetic field strength that can be generated.

On the other hand, when a liquid helium immersion type superconducting magnet is used, there are the following problems.

Since liquid helium cooling is required, the apparatus is complicated and large in size.

ㆍ Handling of liquid helium is complicated and requires operator skill.

• The supply of liquid helium is necessary, and the cost of liquid helium is high.

In addition, in the case of using the conventional split coil as a coil for generating a horizontal magnetic field, the shape is simple and the operation is easy, but the magnetic field generating efficiency into the required space is poor.

On the other hand, when the saddle-shaped coil is used, there are the following problems.

Magnetic field generation efficiency to the required space is good and can be miniaturized, but manufacturing is very difficult. In addition, in the solenoid coil, a tension against the electromagnetic force can be maintained inside the winding by applying a tension during winding and winding. However, in a saddle coil, the tension cannot be maintained in the straight part and the saddle part. Therefore, it is difficult to fix the wire rod against a large electromagnetic force so as not to move.

Therefore, the subject of this invention is the structure which arrange | positions at least two pair of solenoid superconducting coils in the coil shape which generates a horizontal magnetic field using the so-called helium-free superconducting magnet apparatus which conducts and cools a superconducting coil only by a low temperature freezer. It is an object of the present invention to provide a superconducting magnet device for generating a horizontal magnetic field, which can be easily operated and can be miniaturized.

The refrigerator-cooling superconducting magnet device according to the present invention includes a double cylindrical vacuum container having an air space in the center, at least two pairs of superconducting coils arranged vertically in the vacuum container to generate a horizontal magnetic field, and each superconducting member. A cryocooler for cooling a coil, wherein the at least two pairs of superconducting coils are different from the line segments where each pair of superconducting coils face each other with the atmospheric space therebetween, and which connects the centers of one pair of superconducting coils. The angle θ between the line segments connecting the centers of the pair of superconducting coils is disposed adjacent to each other such that the angle θ is 40 ° ≦ θ ≦ 90 ° on the horizontal plane.

In the refrigerator-cooling superconducting magnet device, the low temperature freezer is a two-stage cooling system having a first stage and a second stage refrigeration stage, and the superconducting coil is supported by a bobbin in the vacuum vessel, An insertion hole for inserting the cryocooler is provided on the lower surface or the upper surface thereof, and a sleeve for extending the vacuum vessel from the insertion hole into the vacuum container is fixed to receive the cryocooler in a sealed state. While installing a tip heat transfer member in contact with the cold head of the second stage freezing stage of the cryogenic freezer, and installing an intermediate heat transfer member in contact with the cold head of the first stage freezing stage of the cryogenic freezer, The low temperature freezer body is characterized in that the vacuum container in the cryogenic state detachable configuration. .

In the refrigerator cooling type superconducting magnet device, the vacuum container also has a double cylindrical structure that can surround the atmospheric space, has a cylindrical structure for fixing the bobbin, the superconducting coil and the structure, the The intermediate heat transfer member and the sleeve of the sleeve are accommodated in a double-cylindrical heat radiation shield body disposed in the vacuum container together with the tip portion of the sleeve to prevent stress generation by heat shrink between the heat radiation shield body and the sleeve. It is characterized by connecting the heat radiation shields with a flexible heat transfer body by a mesh or a multilayer board.

In the refrigerator-cooling superconducting magnet device, further, in order to prevent stress generation due to heat shrink between the structure and the sleeve, the front end heat-transfer member of the sleeve and the connecting portion provided in the structure are connected by a multi-layer plate-shaped flexible heat conductor. It is characterized by.

In the refrigerator-cooling superconducting magnet device, the structure is further provided with brackets each having a support plate at a plurality of locations including a portion corresponding to the superconducting coil, and the heat radiation shield at the bottom thereof in the vacuum container. A plurality of vertical load supporting members for supporting the structure while being in surface contact with the supported plate of the bracket through the sieve, and the supported plate of the bracket is slidable with respect to the vertical load supporting member By the heat shrink of the structure, it is characterized in that to reduce the bending load generated in the vertical load support.                     

In the refrigerator cooling type superconducting magnet device, the structure also penetrates through the heat radiation shield body while penetrating the sidewalls in a sealed state in a plurality of places of the side walls of the vacuum container including the portions corresponding to the superconducting coils. Each of the horizontal load bearings connected to each other enables to align the superconducting coil from the outside of the vacuum vessel, and the horizontal load bearings are rotatably supported at the connection portion with the structure. It is done.

The refrigerator-cooling superconducting magnet device further includes a current lead made of an oxide superconductor for supplying current to the superconducting coil, and one end of the current lead has a thermal anchor on the structure and the other of the current lead. One end is characterized in that a thermal anchor is applied to the thermal radiation shield, and at least one end of the current lead is a free end.

In the refrigerator cooling type superconducting magnet device, furthermore, by providing a magnetic shield body on the outer circumference of the vacuum container, the leakage magnetic field of the outer circumference can be reduced.

<Example>

With reference to FIG. 1, the outline | summary of the refrigerator cooling type superconducting magnet apparatus by this invention is demonstrated. In Fig. 1, the superconducting magnet device has a double-cylinder vacuum vessel 10 having an air space in the center and two pairs of solenoid-shaped superconductors arranged vertically in the vacuum vessel 10 to generate a horizontal magnetic field. Coils 11a to 11d and cryogenic chillers (to be described later) for cooling each superconducting coil.

In the present embodiment, in particular, two pairs of superconducting coils 11a to 11d face each other with one pair of superconducting coils 11a and 11b and the other pair of superconducting coils 11c and 11d facing each other with an air space therebetween. The angle between the line segment L1 connecting the centers of one pair of superconducting coils 11a and 11b and the line segment L2 connecting the centers of the other pair of superconducting coils 11c and 11d (hereinafter, (Theta) is adjacently fixed so as to be 40 ° ≤θ≤90 °.

Next, with reference to FIGS. 2-7, embodiment when the present invention is applied to the single-crystal pulling-up magnetic field generating apparatus by MCZ method is described. In Fig. 2, the refrigerator-cooling superconducting magnet device according to this embodiment is disposed around a single crystal growth device (not shown), and as described in Fig. 1, two pairs of superconducting coils 11a to magnetic fields are generated. The vacuum chamber 10 of the sealed structure which accommodated 11d), and the four cryogenic freezers (henceforth a freezer) (12a thru | or 12) which are arrange | positioned inside from the upper surface side of the vacuum container 10, and cool each superconducting coil. 12d). In addition, the installation number of the cryogenic freezer is determined according to the freezing capacity, it is not limited to four.

Hereinafter, a description will be given of the pair of superconducting coils 11a and 11b and their accompanying components, such as the refrigerators 12a and 12b, and the pair of superconducting coils 11c and 11d and the accompanying components. Since the elements are exactly the same, explanation is omitted.

On the upper surface side of the vacuum vessel 10, a current introduction terminal 21 and a vacuum exhaust valve 22 (only a portion corresponding to the refrigerator 12b in FIG. 4) are provided. The vacuum exhaust valve 22 is used to vacuum the inside of the vacuum vessel 10. In addition, a compressor for compressing, supplying and circulating the helium gas, which is a refrigerant, is connected to the cold synchronizer 12b. In simple terms, the refrigerator 12b includes an electric motor for switching rotary valves for switching the introduction and discharge of helium gas, connected to a displacer, to convert the reciprocating motion into a rotary motion, and to set an upper and lower limit of the reciprocating motion. A motion conversion mechanism is provided. In detail, since it is disclosed by Unexamined-Japanese-Patent No. 63-53469, illustration and description are abbreviate | omitted here.

The solenoid superconducting coil 11a is supported by the annular bobbin 13-3 fixed to the structure 13 in the vacuum vessel 10. The structure 13 has a cylindrical shape.

In FIG. 5, the refrigerator 12a includes, for example, a first stage freezing stage 12-1 having a 50K first stage cold head 12-11 and a 4K second stage cold head 12-21. It is a two-stage freezer having a second stage freezing stage (12-2) having a). The freezing stages 12-1 and 12-2 are housed in a sealed state in the sleeve 23.

The sleeve 23 is fixed to the edge of the insertion opening 10-1 provided on the upper surface of the vacuum container 10 by welding or the like. A flange 10-2 is provided around the insertion port 10-1, and the cover member 12-3 of the refrigerator 12a is bolted to the flange 10-2 in a sealed state. As a result, the inner space of the sleeve 23 is completely separated from the inner space of the vacuum container 10 and is completely sealed to the outside. In the sleeve 23, the front end heat transfer member 23-1 for surface contact with the second end cold head 12-21 of the second stage freezing stage 12-2 is provided at the front end thereof. The intermediate heat transfer member 23-2 for contacting the first stage cold head 12-11 of the first stage freezing stage 12-1 is provided in the intermediate portion.

The material of the sleeve 23 is preferably made of stainless, and the material of the tip heat transfer member 23-1 and the intermediate heat transfer member 23-2 is preferably made of copper, but is not limited thereto. . The front end heat transfer member 23-1 of the sleeve 23 is located near the connecting portion 13-1 provided in the structure 13. The tip heat transfer member 23-1 and the connection portion 13-1 are connected by a multilayer plate heat transfer member 14 having flexibility. As a result, stress generation due to heat shrinkage between the coil fixing structure 13 and the sleeve 23 is prevented. In addition, since structural materials, such as SUS, are used normally for the structure 13, when the thermal conductivity from the connection part 13-1 to a superconducting coil is not enough, it is a copper material on the surface of the structure 13 It is preferable to form a heat conduction path by) or the like to increase the cooling efficiency.

Returning to FIG. 3, the vacuum vessel 10 has a double cylinder structure that can surround the single crystal growth apparatus, and the single crystal growth apparatus is disposed in the atmospheric space formed inside the vacuum vessel 10. Since this single crystal growth apparatus is the same as the conventional one, illustration and description are omitted. Two pairs of superconducting coils 11a to 11d impart a horizontal magnetic field to the molten silicon in the crucible of the single crystal growth apparatus.

In addition, the two pairs of superconducting coils 11a to 11d and the structure 13 supporting them are accommodated in the double-cylindrical heat radiation shield body 15 disposed in the vacuum vessel 10 together with the lower portion of the sleeve 23. It is. This heat radiation shielding body 15 is for preventing intrusion of radiant heat. The sleeve 23 extends downward through the upper portion of the heat radiation shielding body 15. In order to prevent stress caused by thermal contraction between the heat radiation shielding body 15 and the sleeve 23, between the intermediate heat transfer member 23-2 and the heat radiation shielding body 15 of the sleeve 23 is a mesh or a multilayer. It is connected to the flexible heat transfer body 25a by a board.

In FIG. 6, the superconducting coil 11a, the structure 13, and the heat radiation shield 15 are supported by the vertical load supporting member 16 provided in the bottom part of the vacuum container 10. In FIG. In detail, the structure 13 is provided with the bracket 13-2 which has the supported plate 13-2a extended in a horizontal direction. The vertical load supporting member 16 is installed at the bottom in the vacuum vessel 10, and passes through the bottom of the heat radiation shielding body 15 and superconducts while being in surface contact with the supported plate 13-2a of the bracket 13-2. The coil 11a and the structure 13 are supported.

In particular, the connection portion with the supported plate 13-2a at the upper end of the vertical load supporting member 16 is made of a material having a small coefficient of friction with respect to the supported plate 13-2a made of metal, for example, Teflon; Plate member 16-1, such as the &quot; trademark &quot; Thereby, the support plate 13-2a of the bracket 13-2 is set to be slidable with respect to the vertical load supporting member 16, and the vertical load supporting member is formed by thermal contraction of the superconducting coil 11a and the structure 13. The bending load generated at (16) is alleviated.

Although not shown in detail, the heat radiation shielding body 15 is supported by a supporting plate 16-2 provided at the middle of the vertical load supporting member 16 at its bottom. In addition, between the support plate 16-2 and the heat radiation shield 15, the heat radiation shield 15 is slidable through a material having a small coefficient of friction as in the above. Moreover, the said vertical load support body 16 is provided in several places containing the position corresponding at least to a superconducting coil.

The side wall of the vacuum vessel 10 is provided with a horizontal load supporting member 17 which penetrates the side wall in a sealed state and penetrates the heat radiation shield body 15 and is connected to the structure 13. The horizontal load bearing member 17 includes a support strap 17-1 made of an endless belt made of resin, a screw shaft 17-2 connected to one end of the support strap 17-1, and a screw shaft ( It consists of a nut 17-3 which is the opposite end of 17-2 and screwed into a screw portion protruding outward from the side wall of the vacuum vessel 10. The other end of the support strap 17-1 is rotatably supported by the structure 13, and one end of the support strap 17-1 is supported rotatably by the screw shaft 17-2. . As a result, the dimensional difference due to heat shrinkage of the vacuum vessel 10, the superconducting coil 11a, and the structure 13 is absorbed.

The screw shaft 17-2 and the side wall of the vacuum container 10 are sealed. The screw part and the nut 17-3 which protrude outside from the side wall of the vacuum container 10 are covered with the cover 10-3 which can be opened and closed. The screw shaft 17-2 and the nut 17-3 are for enabling alignment of the superconducting coil 11a from the outside of the vacuum container 10. Therefore, the heat shrinkage amount of the superconducting coil 11a and the structure 13 is calculated in advance, and the nut 17-3 is loosened so that the superconducting coil 11a and the structure 13 can be displaced by this heat shrinkage amount. do.

As shown in Fig. 2, the horizontal load bearing member 17 has a location corresponding to the superconducting coils 11a to 11d, between the superconducting coil 11a and the superconducting coil 11d, and the superconducting coil 11c and the superconducting. It is provided in six places in total between the coils 11b. Although not shown, the vertical load supporting body 16 is also provided in at least six places corresponding to the installation location of the horizontal load supporting body 17 at least.

2 and 3, the outer periphery of the vacuum container 10 includes an upper magnetic shield body 26-1, a side magnetic shield body 26-2, and a lower magnetic shield body 26-3. The magnetic shield body 26 is provided, so that the leakage magnetic field of the outer peripheral portion can be reduced.

In Fig. 7, the structure 13 is provided with a current lead 27 made of an oxide superconductor for supplying current to the superconducting coil 11b. One end of the current lead 27 takes a thermal anchor on the structure 13, and the other end of the current lead 27 takes a thermal anchor on the thermal radiation shielding body 15. At least one end of the current lead 27 is a free end. The current lead 27 is connected to the current introduction terminal 21 shown in FIG.

Moreover, in the said aspect, although each refrigerator is provided from the upper surface side of the vacuum container 10, you may install from the lower surface side of the vacuum container 10, In this case, it accompanies maintenance of the refrigerator. In order to secure a space for the replacement operation, support portions are provided at a plurality of locations at the bottom of the vacuum container 10.

Next, each said component is demonstrated.

The superconducting coils 11a to 11d may be formed of not only oxide but also metal superconducting wires. The bobbins 13-3 of the superconducting coils 11a to 11d are formed of a material having a high thermal conductivity such as copper and aluminum. When comprised with the material (stainless steel or FRP) with poor thermal conductivity, high thermal conductive materials, such as copper and aluminum, are attached. The superconducting coils 11a to 11d are four coils wound in a solenoid shape on a circumference of the vacuum vessel 10. If the arrangement angles (θ) of superconducting coils that are mutually smaller are smaller, the coil diameter becomes smaller, and in order to generate the required magnetic field in the center of the atmospheric space, the empirical magnetic field of the superconducting coil becomes large enough to break the superconducting state. Throw it away. On the other hand, when the arrangement angle θ is large, the generation efficiency of the magnetic field generated in the center of the air space becomes poor. (When one superconducting coil generates a magnetic field generated at the center of the device, B1, four superconducting coils are combined to form a center. H0 = 4 × B1 × cos (θ / 2). Therefore, the empirical magnetic field is made not so large, the magnetic field generating efficiency to the center is not so low, and the placement angle θ is in the range of 40 ° ≦ θ ≦ 90 °.

Regarding the critical significance of 40 degrees and 90 degrees, first, the relationship between the coil and the magnetic field is shown in FIG. Next, it calculated by putting in a valid value at the time of actually designing, and created FIG.

The scale on the left side of FIG. 9 is 1 when θ = 0, and the relationship between the magnetic field and the angle is calculated and is indicated by a solid line. It can be seen that the smaller the angle, the larger the magnetic field is generated. As a result, the magnetic field is 70% at an angle of 90 degrees, and the magnetic field is less than half at 120 degrees. Therefore, if it is not maintained at 70% of the generated magnetic field, it is 90 degrees because the efficiency of the coil is bad.

The scale on the right side of FIG. 9 calculates the relationship between coil radius and angle by making half of the space | interval of opposing coils (distance with respect to the crucible center) 1, and is shown with the broken line. It can be seen that the larger the angle, the larger the coil radius can be taken. The unit of radius is shown by the ratio at the time of making L = 1. It becomes size that angle is less than 40% at 40 degrees. With respect to the size of the crucible, if the coil radius is less than 40%, the required magnetic field strength cannot be obtained.

Moreover, the graph intersects at around 85 degrees and shows the largest value of both, but on the right side of this point the proportion of the elements of the normalized generated magnetic field increases, and on the left the coil radius is dominant. I know by knowledge.

Therefore, it is preferable to design a practical superconducting magnet in the range of 40 to 90 degrees.

As the freezer, a small GM (Gifford-McMahon) refrigerator or the like can be used. In the case of using a two-stage GM refrigerator, the heat radiation shielding body 15 can be cooled in the first stage cold head 12-11, and the superconducting coil can be cooled in the second stage cold head 12-21. In addition, another cooling device may be added for cooling the heat radiation shielding body 15.

The freezer insert sleeve 23 is fixed to the vacuum container 10, and the sleeve portion 23 is provided with a heat transfer member that is in thermal contact with the freezer. Thereby, the refrigerator main body can be attached to and detached from the vacuum container 10 while being in a cryogenic state. As described above, in the joining of the intermediate heat transfer member 23-2 and the heat radiation shielding body 15, in order to prevent stress caused by heat shrinkage, the structure is connected to a wire or a multilayer plate so as not to transmit force. have.

As the current lead 27 made of the oxide superconductor, a material capable of supplying a current while reducing intrusion heat to the superconducting coil portion, for example, an oxide superconductor such as bismuth based or yttrium based, is used. In addition, as the oxide superconductor, a bulk body and a wire rod shape are applicable. Since this kind of material is a material with low mechanical strength, the joint with the superconducting coil, which needs to reduce heat generation, is fixed and the other end is anchored at the second stage freezing stage temperature of the refrigerator, but stress due to heat shrinkage It is free end for mitigation. Finally, it joins by the flexible member which applied laminated board, a flat wire, etc. Both ends of the oxide superconductor are coated with silver by thermal spraying, and the electrodes are joined by soldering thereon. As a result, a current lead can be made small because of low contact resistance.

The multilayer heat transfer member 14 is used to connect the tip heat transfer member 23-1 and the connection portion 13-1, but the second stage cold head of the refrigerator is directly connected to the structure 13 or the heat transfer member attached thereto. You may make it contact.

The heat radiation shielding body 15 surrounds the superconducting coil in order to reduce heat infiltration into the superconducting coil and reduces the heat radiation. Moreover, in order to raise the effect of reducing heat radiation, it is also possible to use a multilayer heat insulating material (super insulator) together. The heat radiation shield 15 is made of a material having excellent heat transfer characteristics, such as copper and aluminum. In addition, when mechanical strength is needed, it is also possible to use stainless steel as a strength member, and to use copper and aluminum together as a heat transfer member. In addition, in order to prevent overcurrent due to quench of the superconducting coil (uncontrollable and irreversible phenomenon when the superconductor or the superconductor is transferred from the superconducting state to the superconducting state) or the sudden magnetic field fluctuation, the heat radiation shielding body (15) It may be of a structure in which notching is partially inserted into the.

The vertical load supporting member 16 is a member supporting the superconducting coils 11a to 11d, the structure 13, and the heat radiation shielding body 15, and needs to have excellent thermal insulation performance while maintaining mechanical strength. As the material, for example, GFRP, OFRP, alumina FRP, stainless or the like can be used. As a known example, there is a configuration in which a superconducting coil is supported from the vacuum vessel 10 by a plurality of pipe-shaped GFRP materials. This pipe takes the heat radiation shielding body 15 and an anchor in an intermediate part, and aims at reducing invasion heat by conduction. In this embodiment, a plurality of pipes are provided as the vertical load supporting members 16 in the vertical direction, and the superconducting coils are thermally supported.

The horizontal load bearing member 17 is made of a cylindrical or belt-shaped material such as GFRP, OFRP, alumina FRP, stainless steel, etc., and rotates in one or both of the superconducting coil mounting portion and the mounting portion to the vacuum vessel 10. Make it possible. The mounting portion to the vacuum vessel 10 has a structure in which the position of the horizontal load supporting member 17 can be adjusted while maintaining the vacuum tightness, and the superconducting coil and the vacuum vessel 10 can be adjusted in alignment. .

The vacuum container 10 is a container for holding an adiabatic vacuum, and serves as a point for supporting loads of the superconducting coil, the structure 13, the heat radiation shield body 15, the refrigerator, and the like. Formation by a welded structure or a flange structure is also possible. In the case of a flange structure, it becomes easily removable. Even in the case of a welded structure, a removable box may be attached to a part so that only the part where the current lead 27 or the refrigerator is installed can be repaired.

The magnetic shield body 26 is provided with a member made of a ferromagnetic body on the outer side (upper and lower or outer circumferential surfaces, or both) of the vacuum container 10 to reduce the leakage magnetic field to the peripheral portion.                     

With the above structure, it is possible to provide a horizontal magnetic field generating superconducting magnet device for MCZ which is simple in structure, strong in thermal stress, lightweight, compact, easy to operate, and reliable.

As a magnetic field generating source in the production of silicon single crystal by the MCZ method, the action in the case of generating a horizontal magnetic field is as follows.

Start the freezer. Thereafter, the operation related to cooling is unnecessary at all, and does not require skill for cooling.

After several days to ten days, the superconducting coil becomes the superconducting temperature.

When necessary, the excitation power supply is operated to generate a predetermined magnetic field in the single crystal growth apparatus.

By the generated magnetic field (horizontal magnetic field), tropical flow of molten silicon is suppressed and silicon single crystal of stable quality can be obtained.

In addition, in the above embodiment, the case of applying as a magnetic crystal generating device for single crystal pulling by the MCZ method has been described. However, the present invention is not limited thereto, and the present invention is not limited to this. In addition, the present invention can be applied to a refrigeration type superconducting magnet device of a refrigerator in many fields.

According to the refrigerator-cooling type superconducting magnet device according to the present invention, since only the electric power of the compressor for compressor, power of cooling water, and excitation power are required, the running cost can be greatly reduced. In addition, since the magnet portion is light in weight and compact, it is possible to operate at a low power even when the magnet height is moved in the pulling up process. In addition, since the magnetic shield is provided, the leakage magnetic field is reduced, and safety for external equipment and workers is high.

Claims (8)

A double cylindrical vacuum container having an air space in the center, At least two pairs of superconducting coils arranged longitudinally in the vacuum vessel to generate a horizontal magnetic field; Cryogenic chiller for cooling each superconducting coil to cryogenic temperature, The at least two pairs of superconducting coils, each pair of superconducting coils facing each other with the atmospheric space therebetween, and connecting the center of one pair of superconducting coils and the center of the other pair of superconducting coils A refrigerator-cooled superconducting magnet device, characterized in that the angle (θ) between the line segments are disposed adjacent to each other to be 40 ° ≤ θ ≤ 90 ° on the horizontal plane. The method of claim 1, The cryogenic freezer is a two-stage cooling system having a first stage and a second stage freezing stage, wherein the superconducting coil is supported by a bobbin in the vacuum container, and the cryogenic freezer is inserted into a lower surface or an upper surface of the vacuum container. And a sleeve for accommodating the cryogenic freezer in a sealed state extending from the insertion hole into the vacuum vessel from the insertion port, and having a cold head of the second stage freezing stage of the cryogenic freezer at the front end thereof. An intermediate heat transfer member for contacting the cold head of the first stage freezing stage of the cryogenic freezer is provided at the middle of the cryocooler, and the cryocooler main body is in a cryogenic state. A refrigerator-cooling superconducting magnet device, characterized in that it is configured to be detachable. The method of claim 2, The vacuum container has a double cylindrical structure that can surround the atmospheric space, has a cylindrical structure for fixing the bobbin, the superconducting coil and the structure, together with the front end of the sleeve, is disposed in the vacuum container It is housed in a double-cylindrical heat radiation shield body, and between the intermediate heat transfer member and the heat radiation shield body of the sleeve by a wire and a multi-layer plate in order to prevent the stress caused by heat shrink between the heat radiation shield body and the sleeve. A refrigerator-cooling superconducting magnet device, characterized in that connected by a flexible heating element. The method of claim 2, A refrigerator-cooling superconducting magnet device characterized in that the front end heat transfer member of the sleeve and the connecting portion provided in the structure are connected by a multilayer plate-shaped flexible heat transfer body to prevent stress generation due to heat shrinkage between the structure and the sleeve. The method of claim 3, The structure is provided with brackets each having a supported plate at a plurality of locations including a portion corresponding to the superconducting coil, and inside the vacuum vessel, the heat radiation shield is passed through the bottom to allow the A plurality of vertical load supporting members are provided for supporting the structure while being in surface contact with the supported plate, and the supported plate of the bracket is slidable with respect to the vertical load supporting member, so that the thermal contraction of the structure Refrigerating type superconducting magnet apparatus, characterized in that for reducing the bending load generated in the vertical load support. The method of claim 5, A horizontal load supporting member connected to the structure by penetrating the sidewalls in a sealed state and penetrating the sidewalls of the vacuum vessel including a portion corresponding to the superconducting coil in a sealed state, and connected to the structure. The respective arrangements enable positioning of the superconducting coils from the outside of the vacuum container, and the horizontal load bearing body is rotatably supported at the connection portion with the structure. Device. The method of claim 3, A current lead made of an oxide superconductor for supplying current to the superconducting coil, one end of the current lead having a thermal anchor on the structure, and the other end of the current lead having a thermal anchor on the thermal radiation shield. And a free end of at least one end of the current lead. The method of claim 1, A refrigerator-cooling superconducting magnet device, characterized in that the magnetic shield body is installed on the outer circumference of the vacuum vessel to reduce the leakage magnetic field of the outer circumference.

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