JP4852678B2 - Superconducting magnet device with room temperature working plane - Google Patents

Description

  The present invention relates to a superconducting magnet device that applies a magnetic field to an object to be measured, thereby performing physical properties of the object to be measured, various inspections, and tests.

  Specifically, the present invention uses an external space including an external wall surface that constitutes the cryostat as a room temperature work space, and the external wall surface is formed of a material that does not interfere with a magnetic field, and a measurement object and By installing the related equipment, the object to be measured and the related equipment are stably installed, and the room temperature working space that is not limited by the shape and volume of the object to be measured is secured, and the surface is formed flush. The present invention relates to a superconducting magnet device having a room temperature work plane which can be used as a whole. Here, room temperature work means testing and measuring the object to be measured at room temperature, and a room temperature work plane or space means a plane or space for setting the object to be measured at such temperature. It is what.

  Various tests and inspections using superconducting magnets are actively conducted. In addition to tests and inspections, it is actively used in magnetic separation systems using superconducting magnets, measurements in magnetic fields such as spectroscopy, processing in magnetic fields, magnetic field mapping, and various demonstrations showing the effects of magnetic fields. Conventionally, this type of superconducting magnet device uses a narrow external space surrounded by and in contact with a cryostat in which a superconducting magnet is stored as a room temperature working magnetic field space in order to apply a magnetic field uniformly to the object to be measured. An object to be measured was installed in this space (see Non-Patent Documents 1 and 2 and Patent Document 1).

  A superconducting magnet is housed inside the cryostat and is cooled and operated by a refrigerator or a refrigerant. The cryostat, which is used exclusively for testing by applying a magnetic field, applies a strong magnetic field from the stored superconducting magnet to the object to be measured with high uniformity. A room-temperature working space for installing the object to be measured is provided, and a hollow housing formed so as to surround the space is formed, and a superconducting magnet is stored in the housing. FIG. 4 is a cross-sectional view schematically showing the superconducting magnet device. The superconducting magnet 2 is housed in the cryostat 1, and a space surrounded by the cryostat 1 in which the inside of the superconducting magnet is hollow is formed. The room is a cylindrical room-temperature bore 7 which is a space for using a magnetic field, and an object to be measured and related equipment are installed in the room-temperature bore 7. Is a space 3 using a magnetic field.

  The object to be measured is arranged in a cylindrical external space surrounded by the cryostat 2 as described above, with only both ends open, and in the region 3 having a high magnetic field in the room temperature bore 7. In the measurement, a magnetic field is generated by energizing the superconducting magnet 2 stored in the cryostat, and the measurement is performed by applying the magnetic field to the object to be measured (not shown). A conventional superconducting magnet apparatus having such a cryostat usually has a room temperature working space that uses a magnetic field inside the superconducting magnet, so that a strong magnetic field from the superconducting magnet is passed through the housing of the cryostat 1. It is excellent in that it has a structure that can be applied with high uniformity to an object to be measured (not shown) installed at the center of the work space. However, the room temperature working space was a cylindrical narrow external space with both ends open. For this reason, the work is not always easy when measuring, causing inconvenience.

K. Watanabe, S.M. Awaji, J .; Sakuraba, K .; Watagawa, T .; Hasebe, K.M. Jikihara, Y. et al. Yamada and M.M. Ishihara: Cryogenic 36 (1996) 1019 Mitsuhiro Motokawa, Noboru Miura: Maruzen Experimental Physics Course 2 Basic Technology II Experimental Environmental Technology p. 134-150 June 25, 1999 Issued by Maruzen Co., Ltd. Japanese Patent Laid-Open No. 6-132567 (Kazuo Watanabe and three others, "conduction cooling superconducting magnet device")

  The above is an outline of a conventional measuring superconducting magnet apparatus having a room temperature working space, but the room temperature working plane and the room temperature bore 7 are set inside the superconducting magnet, and are narrow, and are measured. Objects, their supporting materials, measuring instruments, etc. were severely limited in size and shape. On the other hand, the objects to be measured, their supporting materials, measuring instruments, etc. have a wide variety of sizes and shapes, and the shapes and sizes are extremely diverse. In a superconducting magnet device surrounded by the cryostat, There were considerable restrictions on the size and shape of the object to be measured, its support material, and measuring equipment. For this reason, there is an inconvenience that the operation itself becomes difficult in the measurement using the superconducting magnet device, and it has been demanded to eliminate such an inconvenience at the research site.

The present invention is intended to meet such a demand. Therefore, as a result of earnest research in the present inventors, in the superconducting magnet device provided with the cryostat, conceived to actively use the open outer space of the cryostat as a space using a magnetic field at room temperature, As a result of further intensive research, this idea has been found to be extremely effective. Here, the outer space where the cryostat is opened is the outer space in the conventional cryostat shown above, and the room temperature bore is a cylindrical outer space where only both ends are opened. And is defined as pointing to the outer space including the surrounding outer wall of the cryostat.
That is, the present invention has been made based on the above findings, and the configuration thereof is as described in ( 1) to (7) below.
(1) A superconducting magnet device comprising a superconducting magnet that can apply a magnetic field to an object to be measured placed on a work plane at room temperature, and a cryostat that holds the superconducting magnet at a low temperature and stores it. The open side outer space of the cryostat is a space that uses a magnetic field at room temperature, and at least a portion of the outer space of the cryostat is used as a room temperature work plane for installing a measurement object when measuring , and the cryostat outer wall is The entire surface is formed as a work surface to secure the work surface, and the inner and outer portions of the periphery and center are the pressure difference between the inside and outside of the cryostat, the temperature difference between before and during operation, the gravity of the object, and the object to be measured. When the magnetic field is magnetized, the measurement object should be prevented from being deformed by stress caused by being pulled toward the superconducting magnet by the magnetic field. With a thick flange structure for, characterized in that the abutment is supported by the lower structure, the superconducting magnet apparatus.
(2) A cryostat outer wall used as a room temperature work plane on which the object to be measured is installed is made of a material that does not interfere with the magnetic field, and a room temperature work plane is provided to apply a magnetic field generated by a large superconducting magnet to the object to be measured. The superconducting magnet device according to (1), wherein the superconducting magnet device is designed to be as thin as possible so as to reduce the distance between the magnet and the superconducting magnet.
(3) The superconducting magnet stored inside the cryostat is spaced from the outer wall with respect to the outer wall of the cryostat used as a room temperature work plane on which the object to be measured is installed, and the outer wall, the superconducting magnet, The superconducting magnet device according to (1) or (2) , wherein a vacuum insulation structure is provided between the two .
(4) The superconducting magnet device according to (3) , wherein the interval is 1 mm or more and 20 mm or less.
(5) at room temperature work plane to place the object to be measured provided in the cryostat, by directing the cryostat in any direction, made it possible to be oriented in any direction, either (1) to (4) A superconducting magnet device as described above.
(6) The superconducting magnet device according to (5), wherein the room temperature work plane is provided on a top plate of the cryostat.
(7) The superconducting magnet device according to (5), wherein the room temperature working plane is provided in two or more.

  According to the present invention, at least a part of the open outer wall of the cryostat is a room temperature work plane on which an object to be measured is installed, so that it is opened from a narrow room temperature work space surrounded by the cryostat as in the prior art. The present invention makes it possible to provide a superconducting magnet device having a room temperature working space, and thereby succeeds in securing a wide room temperature working space in the superconducting magnet device. This success eliminates the inconvenience of the size and shape of the object to be measured, which will greatly reduce the inconvenience in the future.

  Hereinafter, the present invention will be specifically described based on the drawings and examples. However, it should be noted that the present invention is not limited by these examples. 1 to 3 are views (cross-sectional views) each showing an aspect of a superconducting magnet device having a room temperature working plane according to the present invention.

  FIG. 1 is a cross-sectional view of an apparatus showing an aspect showing that an upper top plate 1a of a cryostat is a plane on which an object to be measured is arranged. In this figure, a superconducting magnet device A is set in a container structure by a cryostat peripheral outer wall 1 and a cryostat top plate 1a, and as a heat insulating plate (radiation shield plate) via a small gap directly below the top plate 1a. Aluminum is vapor-deposited on one side of a film such as polyester, and super-insulation 1e formed by laminating in a multilayer structure, a radiation shield 1b formed of a nonmagnetic metal having good thermal conductivity such as aluminum metal or copper is fixed, The superconducting magnet 2, the refrigerator 1c, and the heat load flange (cooling stage) 1c (b), (b) of the refrigerator 1c are stored in the radiation shield 1b.

A space is provided between the cryostat peripheral outer wall 1 and the super insulation 1e and the radiation shield 1b to form a vacuum structure, thereby forming a heat insulating layer 1d. Furthermore, the space surrounded by the refrigerator 1c and the radiation shield 1b communicates with the space surrounded by the cryostat surrounding outer wall 1 and the radiation shield 1b, and a vacuum heat insulating layer 1d is formed.
The cryostat top plate 1a is formed as thin as possible so that the magnetic field of the superconducting magnet stored in the cryostat can be applied to the object to be measured without being attenuated. The cryostat top plate has drawbacks such as weakness against a set partial stress, and it is necessary to prevent this. In the present invention, as a countermeasure against deformation due to stress, the peripheral portion and the central portion of the cryostat top plate 1a are made into a thick flange structure 6 and supported by the cryostat peripheral outer wall 1 and the cryostat top plate support member 5 which are lower structural members. In this way, the top plate is prevented from being deformed by stress.

  Further, in the case of the superconducting magnet apparatus employing the multi-stage refrigerator cooling system shown in FIG. 1, the cryostat top plate support material 5 is supported by the refrigerator immediately below, in this example, 1c (A). Further, the lower one is configured to support the structure in the upper stage. These specific attachment structures and fixing means can be set by known attachment structures and fixing means.

  That is, the refrigerator that supports the cryostat top plate support member 5 is supported by the refrigerator 1c, and the lower portion of the cryostat communicates with a refrigerator refrigerant gas source (not shown).

  Next, FIG. 2 shows another embodiment of the present invention. The superconducting magnet shown in FIG. 1 is installed by rotating it 90 degrees, and the central thick part of both top plates is designed to be reinforced and supported by a single support member 5. The remaining elements and the arrangement structure of the elements are basically the same as in FIG. By this aspect, the plane and space on which the object to be measured is placed can be set widely. By directing the cryostat in any direction, it is possible to point both tops in any direction, increasing the surface for placing objects to be measured and improving the efficiency of room temperature measurement work compared to a single top. To do. However, since the object to be measured placed on either one of the top plates or both the top plates falls from the top plate, in this case, the object to be measured may be fixed by fixing means (not shown).

  FIG. 3 is a conceptual diagram of a superconducting magnet apparatus having a room temperature working plane according to the present invention. The cryostat has a single container structure in which the superconducting magnet 2 is stored and installed. When the superconducting magnet 2 is cooled by a refrigerator, a gap is provided between the end surface 2a of the superconducting magnet, the outer wall 1 of the cryostat A, and the top plate 1a, and is maintained in a vacuum. In addition, when a system in which the superconducting magnet is immersed and cooled in the refrigerant is employed, the cryostat A is provided with a seal structure that does not dissipate the internal refrigerant, or has a holding mechanism such as a heat insulation mechanism or a recovery mechanism. Added. Regardless of which cooling system is adopted, the installation position of the object to be measured can be set on both top plates 1a, and has a structure that can secure a wide open room temperature working surface.

  Next, the operating procedure of the superconducting magnet apparatus of the present invention shown in FIG. 1 will be described based on an embodiment. In FIG. 1, a space including the room temperature work plane 4 is a space 3 that uses a magnetic field, and an object to be magnetically applied and an object to be measured are installed therein. In the superconducting magnet apparatus A of this example, the superconducting magnet 2 is housed in the cryostat 1 and supported by a refrigerator (1c in FIG. 1) installed in the cryostat 1 to cool the superconducting magnet 2. It is a superconducting magnet device of the refrigerator cooling system by a system that operates in the same manner.

  The cryostat top plate 1a is made of, for example, a thin stainless steel plate that does not interfere with a magnetic field. This thin stainless steel plate has a pressure difference between the inside and outside of the cryostat, a temperature difference, or the gravity of the measurement object or related equipment to be installed, and the direction of the superconducting magnet due to the magnetic field when the object to be measured shows magnetism. A stress that deforms the plane is exerted by a force attracted to the plane, and the plane is deformed. In the present invention, in order to prevent this deformation, the central portion and the outer peripheral portion 6 of the cryostat top plate 1a are each made of a thick flange design and solved by a structure that is supported by a lower structure. The outer peripheral portion was supported by a flange joint of the lower cryostat 1 and the center portion was set to be supported by a cryostat top plate support material 5 supported by a refrigerator.

  The cryostat top plate support 5 is supported by a refrigerator that cools the superconducting magnet 2. As this refrigerator, a multistage refrigerator cooling system arranged in multiple stages can be employed. In that case, the upper one is set to be supported by the lower refrigerator. In this example, the cryostat top plate support 5 is supported by a refrigerator 2 stage heat load flange (also called a refrigerator 2 stage cooling stage) 1c (b) and cooled by the radiation shield 1b, The cryostat top plate 1a at room temperature is supported. Therefore, the cryostat top plate support 5 is supplied from the cryostat top plate 1a at room temperature and the refrigerator 1 stage heat load flange (refrigerator 1 stage cooling stage) 1c (b) at a higher temperature than the refrigerator 2 stage heat load flange. In order to prevent thermal intrusion, it is made of a material having as low a thermal conductivity as possible, and suppresses the temperature rise of the superconducting magnet 2.

  The means for preventing deformation due to stress on the work plane on which the object to be measured is installed is as described above. The cryostat top board 1a serving as the work plane uses the cryostat top board support material 5 having a positive thermal expansion coefficient. Then, in order to be flat when cooled to the design temperature, at room temperature, it is pushed by the cryostat top plate support material 5 to become a convex surface, shrinks by cooling, and becomes a flat surface.

  The range in which the cryostat top plate 1a is deformed by the thermal contraction of the cryostat top plate support member 5 is limited to a region where the cryostat top plate 1a can behave elastically. In order to reduce the heat penetration into the superconducting magnet 2 to an operable level, a radiation shield 1b, a vacuum heat insulating layer 1d, and a super insulation 1e are installed. The smaller the distance between the superconducting magnet end surface 2a and the room temperature work plane 4, the higher the strength of the magnetic field obtained on the room temperature work plane 4, but the radiation shield 1b, super insulation 1e, cryostat top plate support 5 It is installed so as not to come into contact with the conductive magnet 2 or the superconductive magnet winding frame 2b.

Next, the operating procedure of the embodiment shown in FIG. 2 will be described. Basically, it is the same as the first embodiment and does not change.
In FIG. 2, a space including the room temperature work plane 4 is a space 3 that uses a magnetic field, and a target to which a magnetic field is applied is placed on this plane. In this example, there are two room temperature working planes 4, and a space 3 using a magnetic field exists on both sides of the superconducting magnet 2. The superconducting magnet device of this example is a type in which the stored superconducting magnet 2 is cooled by a refrigerator 1c installed in the cryostat 1, that is, a superconducting magnet device using a refrigerator cooling system.

  In order to prevent the room temperature work plane 4 from being deformed by the stress acting on the cryostat top plate 1a, the outer peripheral support structure 6 with thick flanges is provided on the outer periphery of the cryostat top plate support member 5 and the cryostat top plate 1a. It is formed. In that case, the cryostat top plate support material 5 is made of a material having a positive thermal expansion coefficient, and its length is adjusted in consideration of the thermal contraction due to cooling. The deformation-preventing cryostat top plate support 5 is cooled and supported by a radiation shield 1b installed on a refrigerator 1-stage heat load flange (refrigerator 1-stage cooling stage) 1c (b), while at room temperature. The cryostat top plate 1a is supported. Therefore, this top plate support material 5 can be used to prevent the heat penetration from the cryostat top plate 1a at room temperature, which is higher than the refrigerator 1 stage heat load flange (refrigerator 2 stage cooling stage) 1c (b). As much as possible, a material having a low thermal conductivity is used to suppress the temperature rise of the superconducting magnet 2.

  The cryostat top board 1a is pressed by the cryostat top board support material 5 at a room temperature so as to be flat when the cryostat top board support material 5 is cooled to the design temperature. The range in which the cryostat top plate 1a is deformed by the thermal contraction of the cryostat top plate support material 5 is limited to the region where the cryostat top plate 1a can behave elastically. In order to reduce the heat penetration into the superconducting magnet 2 to an operable level, a radiation shield 1b, a vacuum heat insulating layer 1d, and a super insulation 1e are installed. The smaller the distance between the superconducting magnet end surface 2a and the room temperature work plane 4, the higher the strength of the magnetic field obtained on the room temperature work plane 4, but the radiation shield 1b, super insulation 1e, and cryostat top plate support 5 are superconductive. It is installed so as not to come into contact with the magnet 2 or the superconducting magnet winding frame 2b. These design aspects are basically the same as those of the first embodiment described with reference to FIG.

  In recent years, technological development using a magnetic field has become active, and the fields of use have been diverse. In particular, a measurement technique using a magnetic field has become established and important as one of the basic measurement techniques. The objects to be measured are also diversified, and it is required to measure various shapes and sizes. The present invention meets such a demand and is expected to be widely used and spread in the future.

The figure which shows the example 1 of an aspect of the superconducting magnet apparatus provided with the room temperature work plane of this invention. The figure which shows the example 2 of an aspect of the superconducting magnet apparatus provided with the room temperature work plane of this invention. The figure explaining notionally the superconducting magnet apparatus provided with the room temperature work plane of this invention. The figure which shows the superconducting magnet apparatus provided with the conventional room temperature work plane.

Explanation of symbols

1. Cryostat 1a. Cryostat top plate 1b. Radiation shield, 1c. Refrigerator 1c (I) Refrigerator 1 stage heat load flange (Refrigerator 1 stage cooling stage)
1c (b) (refrigerator two-stage cooling stage)
1d. Insulating vacuum layer 1e. Super insulation 2. Superconducting magnet 2a. Superconducting magnet end face 2b. Superconducting magnet reel 3. 3. Space using magnetic field 4. Room temperature working plane 5. Cryostat top plate support material 6. Cryostat top plate outer periphery support structure Room temperature bore

Claims (7)

In a superconducting magnet apparatus comprising a superconducting magnet capable of applying a magnetic field to an object to be measured placed on a work plane at room temperature and a cryostat for storing and storing the superconducting magnet at a low temperature, a cryostat is provided. The open side outer space is a space that uses a magnetic field at room temperature, and at least a part of the outer space of the outer space is used as a room temperature work plane for installing an object to be measured , and the cryostat outer wall The inner and outer parts of the periphery and the central part are formed to be the same as the work surface, the pressure difference between the inside and outside of the cryostat, the temperature difference between before and during operation, the gravity of the mounted object, and the object to be measured are magnetized. In order to prevent deformation due to stress caused by the object to be measured being pulled toward the superconducting magnet by a magnetic field. With a thickness flange structure, abutting by the lower structure, characterized in that it is supported, the superconducting magnet apparatus.   The cryostat outer wall used as a room temperature work plane on which the object to be measured is installed is made of a material that does not interfere with the magnetic field, and the room temperature work plane and the superconductivity are provided to give a magnetic field generated by a large superconducting magnet to the object to be measured The superconducting magnet device according to claim 1, wherein the superconducting magnet device is designed with a plate as thin as possible so as to reduce a distance between the magnets. The superconducting magnet housed inside the cryostat is placed at a distance from the outer wall with respect to the outer wall of the cryostat used as a room temperature work plane on which the object to be measured is placed, and there is a gap between the outer wall and the superconducting magnet. characterized in that it is vacuum insulated superconducting magnet apparatus according to claim 1 or 2. The superconducting magnet device according to claim 3 , wherein the interval is 1 mm or more and 20 mm or less. RT working plane to place the object to be measured provided in the cryostat, by directing the cryostat in any direction, made it possible to be oriented in any direction, according to any one of claims 1 to 4 Superconducting magnet device. 6. The superconducting magnet device according to claim 5 , wherein the room temperature working plane is provided on a cryostat upper top plate. The superconducting magnet device according to claim 5 , wherein the room temperature work plane is provided in two or more surfaces.