CN115312285A - A Bitter-like FeSeTe Superconducting Magnet System - Google Patents

Abstract

The invention discloses a kind of Bitter type FeSeTe superconducting magnet system, which comprises two parts, an excitation low temperature superconducting coil and a FeSeTe high temperature superconducting coil. FeSeTe high temperature superconducting coils include FeSeTeBitter wafers, insulating sheets, cover plates, tie rods and heaters. The FeSeTeBitter wafers are prepared by growing the buffer layer and the FeSeTe superconducting layer on the Hastelloy wafers, then alternately stack the FeSeTeBitter wafers and the insulating wafers, and use the tie rods and nuts to pass through the small holes between the FeSeTeBitter wafers and the insulating wafers to make The holes on the two are aligned. Then the device is fixed by the cover plate and the pull rod, and the upper and lower cover plates are in contact with the insulating sheet. Finally, fix the heater on the cover plate. The FeSeTe high-temperature superconducting coil is placed in the center of the excitation low-temperature superconducting coil to complete the preparation of the entire magnet.

Description

A kind of Bitter-like FeSeTe superconducting magnet system

technical field

The invention belongs to the field of superconducting magnet preparation, and in particular relates to a Bitter-like FeSeTe superconducting magnet system.

Background technique

Superconducting magnets have the advantages of high stability, low loss, long life, and low operating costs, and are ideal equipment for providing a magnetic field environment. Superconducting magnet technology is an indispensable key technology in the fields of future nuclear fusion reactors, high-energy particle accelerators, nuclear magnetic resonance imaging, and spallation neutron sources. Low-temperature superconducting materials (LTS) cannot operate in ultra-high-field environments due to their limited field strength. High-temperature superconducting materials (HTS) have broad application prospects in the field of high-field magnets due to their advantages such as high critical temperature, high critical magnetic field, and high current-carrying capacity. However, the development cost of the full HTS high-field magnet is very high, the strain on the material is huge, and the risk of failure is high. Therefore, the HTS-LTS hybrid magnet solution is currently a particularly effective method for achieving high magnetic fields by superconducting magnets. The large-aperture low-temperature superconducting magnet is used as a back field magnet to provide a uniform magnetic field environment. The high-temperature superconducting magnet is inserted in the low temperature back field magnet.

Existing interpolation high-temperature superconducting magnets mainly include solenoid superconducting magnets and Bitter-type superconducting magnets. The Bitter-like superconducting magnet proposed by the present invention is based on the improvement of the Bitter-type superconducting magnet. Compared with the solenoid superconducting magnet, there is no need to prepare joints, and the resistance of the joints is reduced; the interior has more Holes, faster heat dissipation; no need to wind the strip, directly stacked by Bitter sheets; no need to bend and twist the strip, reducing the damage to the performance of the strip; no need to connect the current through the current lead, The stability of the magnetic field is improved; the layered stacked structure reduces the effect of the hoop force; under the action of the axial compression force, the acting surface is the round surface of the Bitter plate, which has a large active area and little damage to the performance , the Bitter slices will compress each other before, which will improve the stability of the structure. Since the Bitter-like superconducting magnet has no external joints, the quenching method is to heat the magnet, and the magnet is quenched when the critical transition temperature is exceeded. The critical transition temperature of FeSeTe high-temperature superconducting materials is low, usually only about 10K in the preparation method, which is much lower than that of YBCO and other high-temperature superconducting materials, making it easier to control the operation of the device.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention provides a kind of Bitter-type FeSeTe superconducting magnet system, through the alternate stacking of FeSeTe Bitter discs and insulating sheets, using pull rods and nuts to pass through the small hole in the middle of the FeSeTe Bitter discs and insulating sheets, so that the two Align the small holes on the top of the device, and then fix the device through the cover plate and the pull rod. Finally, fix the heater on the cover. The FeSeTe high temperature superconducting coil is excited by exciting the low temperature superconducting coil to realize the stable operation of the magnetic field environment in the FeSeTeBitter coil.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A kind of Bitter-type FeSeTe superconducting magnet system is characterized in that it includes two parts: an excitation low-temperature superconducting coil and a FeSeTe high-temperature superconducting coil, wherein,

The excitation low-temperature superconducting coil is composed of NbTi and Nb ₃ Sn superconducting coils;

The FeSeTe high-temperature superconducting coil includes FeSeTe Bitter discs, insulating sheets, cover plates, small hole rods and heaters; FeSeTe Bitter discs and insulating sheets are alternately stacked, and small hole rods and nuts are used to pass through the FeSeTe Bitter discs and The small hole in the middle of the insulating sheet, so that the small holes on the two tops are aligned; then fix it through the cover plate and the pull rod, the upper and lower cover plates are in contact with the insulating sheet; finally fix the heater on the cover plate;

The FeSeTe high temperature superconducting coil is placed at the center of the exciting low temperature superconducting coil.

Further, the FeSeTe Bitter disc is prepared by growing a buffer layer and a FeSeTe superconducting layer on a Hastelloy disc.

Further, there are several small holes on the FeSeTe Bitter wafer to rapidly dissipate heat and change the current distribution.

Further, the insulating sheet is made of AlN, which plays the role of insulation between FeSeTe Bitter wafers.

Further, the FeSeTe high-temperature superconducting coil has no internal joints, external joints and current leads, which reduces the heat leakage of the magnet during operation and improves the stability of the magnetic field.

Further, the heater is made of manganese-copper wire, and one is arranged on the upper and lower cover plates respectively. By heating the manganin wire, the temperature of the environment of the interpolation magnet is increased, thereby controlling the operation of the interposition magnet.

The beneficial effect of the present invention compared with prior art is:

The interpolation coil of the magnet system of the present invention does not need joints and current leads, which reduces the resistance of the magnet, reduces the heat leakage of the magnet during operation, and improves the stability of the system; the superconducting material of the interpolation coil of the magnet system of the present invention does not need to be twisted and twisted Bending to prevent damage to strip properties;

The interpolation coil superconducting material of the magnet system of the present invention has a layered stacking structure, which can effectively reduce the effect of the hoop force, and under the action of the compression force of the axial force, the damage to the performance of the strip is small, and the Bitter sheets will interact with each other Compression will improve the stability of the structure;

The interpolation coil of the magnet system of the present invention has a porous structure, can dissipate heat quickly, and can realize current redistribution;

The critical temperature of the interpolation coil of the magnet system of the present invention is lower, and the operation of the system can be better controlled by the heater.

Description of drawings

Fig. 1 is the FeSeTe Bitter disc structure schematic diagram among the present invention;

Figure 2 is a schematic diagram of the structure of the FeSeTe high temperature superconducting coil in the present invention, in the figure: 1- cover plate, 2- small hole tie rod, 3- heater, 4- tie rod, 5- alternately stacked FeSeTe Bitter discs and insulating sheets ;

Figure 3 is a schematic structural diagram of the Bitter-like FeSeTe superconducting magnet system of the present invention, in which: 6-excitation low-temperature superconducting coil, 7-FeSeTe high-temperature superconducting coil, 8-insulating sheet, 9-FeSeTe Bitter disc.

Detailed ways

In order to illustrate the embodiments of the present invention or existing technical solutions more clearly, the following briefly introduces the prior art and the accompanying drawings used in the description of the embodiments.

The invention discloses a Bitter-like FeSeTe superconducting magnet system, which includes two parts: an excitation low-temperature superconducting coil 6 and a FeSeTe high-temperature superconducting coil 7 . Among them, the FeSeTe high temperature superconducting coil 7 is the core part. The excitation low-temperature superconducting coil 6 is composed of NbTi and Nb ₃ Sn superconducting coils. The FeSeTe high-temperature superconducting coil 7 has no internal joints, external joints and current leads, which reduces the heat leakage of the magnet during operation and improves the stability of the magnetic field.

As shown in Fig. 1 and Fig. 3, the FeSeTe Bitter wafer 9 has a porous structure. The FeSeTe Bitter disc 9 is prepared by growing a buffer layer and a FeSeTe superconducting layer on a Hastelloy disc with a porous structure. The porous structure can quickly dissipate heat and change the current distribution.

As shown in FIG. 2 and FIG. 3 , the FeSeTe high temperature superconducting coil 7 includes a FeSeTe Bitter disc 9 , an insulating sheet 8 , a cover plate 1 , a small hole rod 2 and a heater 3 . The FeSeTe Bitter disc 9 and the insulating sheet 8 are stacked alternately, and the small hole rod 2 and the nut are used to pass through the small hole in the middle of the FeSeTe Bitter disc 9 and the insulating sheet 8, so that the small holes on the two are aligned to form an alternately stacked FeSeTe Bitter wafer and insulating sheet5. Then the device is fixed by the cover plate 1 and the pull rod 4 , and the upper and lower cover plates 1 are in contact with the insulating sheet 8 . Finally, the heater 3 is fixed on the cover plate 1 .

The layered stacking structure between the FeSeTe Bitter disc 9 and the insulating sheet 8 can effectively reduce the effect of the hoop force, and under the action of the compressive force of the axial force, the performance of the strip is less damaged, and the Bitter sheet will Compress each other to improve the stability of the structure. The insulating sheet 8 is made of AlN, and plays the role of insulation between the FeSeTe Bitter wafers 9 . Moreover, AlN has good thermal conductivity and a small thermal expansion coefficient, and is a good heat-shock resistant material, which can better guide the heat generated during the operation of the FeSeTe Bitter disc 9 in the middle of the magnet. The heater 3 is made of manganese copper wire, and one is arranged on the upper and lower cover plates 1 respectively. By heating the manganin wire, the temperature of the environment of the interpolation magnet is increased, thereby controlling the operation of the interposition magnet. Because the heater 3 is immersed in liquid helium, the temperature rise produced by it is limited, so the high-temperature superconducting strip with a higher critical temperature cannot be quenched due to the temperature rise, and the critical temperature of FeSeTe is lower, and the heater 3 can Better control over the operation of the system.

As shown in FIG. 3 , the FeSeTe high-temperature superconducting coil 7 is placed at the center of the exciting low-temperature superconducting coil 6 , and the entire system is placed in liquid helium to keep the magnet in a low-temperature and safe operating environment. First, current is passed through the excitation low-temperature superconducting coil 6 , and an induced current is generated in the FeSeTe high-temperature superconducting coil 7 . Then, the heater 3 is energized to quench the FeSeTe high temperature superconducting coil 7, and then the heater 3 is turned off. Finally, reducing the current of the exciting low-temperature superconducting coil 6 to zero will induce a current in the FeSeTe high-temperature superconducting coil 7, thereby obtaining a stable magnetic field. In addition, the magnetic field generated by exciting the low-temperature superconducting coil 6 and the FeSeTe high-temperature superconducting coil 7 can be superimposed to obtain a high field.

Although the illustrative specific embodiments of the present invention have been described above, so that those skilled in the art can understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, As long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

Claims (6)

1. A kind of Bitter type FeSeTe superconducting magnet system, it is characterized in that: comprise excitation low-temperature superconducting coil and FeSeTe high-temperature superconducting coil two parts, wherein, The excitation low-temperature superconducting coil is composed of NbTi and Nb ₃ Sn superconducting coils; The FeSeTe high-temperature superconducting coil includes FeSeTe Bitter discs, insulating sheets, cover plates, small hole rods and heaters; FeSeTe Bitter discs and insulating sheets are alternately stacked, and small hole rods and nuts are used to pass through the FeSeTe Bitter discs and The small hole in the middle of the insulating sheet, so that the small holes on the two tops are aligned; then fix it through the cover plate and the pull rod, the upper and lower cover plates are in contact with the insulating sheet; finally fix the heater on the cover plate; The FeSeTe high temperature superconducting coil is placed at the center of the exciting low temperature superconducting coil. 2 . The Bitter-like FeSeTe superconducting magnet system according to claim 1 , wherein the FeSeTe Bitter disc is prepared by growing a buffer layer and a FeSeTe superconducting layer on a Hastelloy disc. 3 . 3. A kind of Bitter-like FeSeTe superconducting magnet system according to claim 1, characterized in that: said FeSeTe Bitter disc has a number of small holes above, which play the role of rapidly dissipating heat and changing the current distribution. 4 . The Bitter-like FeSeTe superconducting magnet system according to claim 1 , wherein the insulating sheet is made of AlN, which plays the role of insulation between FeSeTe Bitter discs. 5. a kind of Bitter-type FeSeTe superconducting magnet system according to claim 1, is characterized in that: described FeSeTe high temperature superconducting coil has no inner connector, outer connector and current lead wire, reduces the leakage heat of magnet during operation , to improve the stability of the magnetic field. 6 . The Bitter-like FeSeTe superconducting magnet system according to claim 1 , wherein the heater is wound by manganin wire, and one is arranged on the upper and lower cover plates respectively. 6 . By heating the manganin wire, the temperature of the environment of the interpolation magnet is increased, thereby controlling the operation of the interposition magnet.

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