JPH0638208U - Conduction cooling type superconducting electromagnet device - Google Patents

Abstract

(57) [Summary] [Objective] To provide a conduction cooling type superconducting electromagnet device capable of miniaturizing the entire device and enhancing the magnetic shield effect of the electromagnet part. [Structure] The shield portion 5 is made larger than the electromagnet portion 10 to have a magnetic shield function of magnetically shielding the electromagnet portion 10 and a radiation shield function of shielding heat radiation from the electromagnet portion 10. The shield part 5 covered the electromagnet part 10 together with the second stage 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a conduction cooling type superconducting electromagnet device.

[0002]

[Prior art]

 Conventionally, the conduction cooling type superconducting electromagnet apparatus shown in FIG. 2 has been proposed.

As shown in FIG. 2, the conduction cooling type superconducting electromagnet apparatus includes an electromagnet portion 10 having a superconducting coil 1 and a cylindrical winding frame 2 around which the superconducting coil 1 is wound, and an electromagnet portion 10 accommodated therein. The magnetic shield part 3 is provided. A refrigerator 20 is provided below the electromagnet section 10. The refrigerator 20 is called a cold storage two-stage refrigerator, and is provided below the first stage 11 and has a first stage portion 21 for heat transfer cooling of the first stage 11 and a lower portion of the second stage 12. And a second stage portion 22 for heat transfer cooling of the second stage 22.

On the second stage 12, a magnetic shield section 3 for fixing the magnetic flux from the electromagnet section 10 is fixed. Further, below the second stage 12, there are provided current leads 13 made of metal oxide superconductors connected to the ends of the superconducting coil 1 of the electromagnet section 10, respectively. The entire portion above the first stage 11 is covered with a cylindrical cap-shaped radiation shield 4 that shields the radiant heat from the electromagnet 10. The lower open end of the radiation shield 4 is covered by the first stage 11 It is fixed to the upper surface of the and is tightly closed inside.

The first stage 21 of the refrigerator 20 below the first stage 11 is fixed on the container bottom 31 and is parallel to the first stage 21 around the first stage 21. A copper current lead 14 extends through the first stage 11 and is connected to the current lead 13 through a through hole 11a provided in the first stage 11. A portion above the container bottom 31 is covered with a cylindrical cap-shaped vacuum container 30. The magnetic shield section 3 of such a conduction cooling type superconducting electromagnet apparatus is formed by surrounding the electromagnet section 10 close to it. This magnetic shield part 3 is cooled together with the electromagnet part 10 to a level of 10K in absolute temperature.

[0006]

[Problems to be solved by the device]

 However, in the conventional example shown in FIG. 2, since the magnetic shield part 3 is close to the electromagnet part 10, the magnetic shield part 3 is magnetically saturated by the magnetic flux 40 forming a high magnetic field, and the shield effect is improved. bad. Furthermore, not only the electromagnet section 10 but also the magnetic shield section 3 having a low temperature of about 10 K is wasteful or increases the load on the refrigerator, so that the superconducting electromagnet apparatus 12 of this type is There was a defect that the time required to cool the electromagnet section 10 to a desired temperature was long.

Therefore, a technical problem of the present invention is to provide a conduction cooling type superconducting electromagnet device which can miniaturize the entire device and enhance the magnetic shield effect of the electromagnet part.

[0008]

[Means for Solving the Problems]

 According to the present invention, a refrigerator having a first stage for cooling the first stage and a second stage for cooling the second stage above the first stage, and the second stage An electromagnet part disposed above and having a superconducting coil, a current lead electrically connected to the electromagnet part and extending from the lower end of the second stage through the first stage, and the electromagnet. In a conduction cooling type superconducting electromagnet device having a magnetic shield part for magnetically shielding the part, the electromagnet part is covered with the second stage by a shield part which also serves as a magnetic shield and a radiation shield. A conduction cooling type superconducting electromagnet device is obtained.

According to the present invention, in the conduction cooling type superconducting electromagnet apparatus, the shield part is supported by a heat conductive support rod provided on the first stage, and the conduction cooling type superconducting superconducting magnet is provided. An electromagnet device is obtained.

[0010]

[Action]

 In the conduction cooling type superconducting electromagnet device of the present invention, the shield part covers the electromagnet part together with the second stage at a position farther from it, so that the magnetic field of the electromagnet part is saturated in a low magnetic field position. It can be shielded without the need to improve the shielding effect, and the cooling efficiency can be improved by cooling the shield part to a temperature level higher than 10K in the first stage via the electrothermal support rod. Also, the shield can be made compact by having two functions, a magnetic shield and a radiation shield.

[0011]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a conduction cooling type superconducting electromagnet apparatus according to an embodiment of the present invention. As shown in FIG. 1, the conduction cooling type superconducting electromagnet apparatus includes an electromagnet section 10 having a superconducting coil 1 and a winding frame 2 around which the superconducting coil 1 is wound. Below the reel 2, there is provided a refrigerator 20 having a second step portion 22 for cooling the second stage 12 and a first step portion 21 for cooling the first stage 11.

The difference between the embodiment of the present invention shown in FIG. 1 and the conventional example shown in FIG. 2 is that an integrated shield portion 5 that serves both as a magnetic shield and a radiation shield is formed. The shield part 5 extends from the upper part of the electromagnet part 10 to the lower part of the second stage 12. In particular, the side wall of the shield part 5 is set sufficiently away from the outer circumference of the electromagnet part 10.

The current leads 13 on both sides of the second stage 12 and the second stage portion 22 of the refrigerator provided in the central portion are provided with through holes provided in the bottom wall of the shield portion 5 from the second stage 12. 7 through each of them, leading to the first stage 11. A plurality of heat transfer support rods 8 are provided between the edge of the bottom wall of the shield part 5 and the edge of the first stage 11, and the circumference of the heat transfer support bar 8 is covered with a cylindrical heat insulating part 9. There is. Between the first stage 11 and the bottom 31 of the empty container 30, the first stage 21 of the refrigerator 20 and the copper current lead 14 are arranged as in the conventional example. The entire apparatus described above is covered with a cup-shaped vacuum container 30.

Both ends of the superconducting coil 1 are respectively connected to the current leads 13 and are respectively connected to the terminals 23 provided on the bottom 31 of the vacuum container 30 via the copper current leads 14.

Here, the cooling of the shield part 5 is performed to a liquid nitrogen temperature level higher than 10 K by the first stage 11 of the refrigerator via the heat transfer support rod 8 supporting the shield part 5. It

Since the main role of the shield part 5 is to block the magnetic flux to the current lead 13, the shield part is provided at the low temperature end of the current lead 13 (on the second stage 12 side of the refrigerator). 5 is provided, but unlike the conventional shield position, it is farther from the electromagnet section 10 side. Since the magnetic field at the bottom of the shield portion 5 is lower than that at the bottom of the conventional magnetic shield 3, magnetic saturation is less likely to occur, magnetic shielding is facilitated, and leakage flux to the current lead 13 can be further reduced. The electromagnet section 10 is cooled to the 10K level from the second stage, but the shield section 5 is cooled by the first stage of the refrigerator and stopped at the liquid nitrogen temperature level. This reduces the cooling loss of the second stage (10K level). Further, the cooling time of the electromagnet section 10 can be shortened, the refrigerating capacity of the first stage stage 11 can be effectively utilized, and the magnetic shield effect can be increased.

[0017]

[Effect of device]

 As described above, in the present invention, since the shield part is installed in the lower magnetic field part apart from the electromagnet part, it is possible to provide a conduction cooling type superconducting electromagnet device having a high magnetic shield effect. .

Further, according to the present invention, since the shield part has two functions of a magnetic shield and a radiation shield, it is possible to provide a compact conduction cooling type superconducting electromagnet device.

Further, according to the present invention, the heat load of the first stage and the second stage is more evenly distributed by cooling the shield part in the first stage of the refrigerator. As a result, a conduction cooling type superconducting electromagnet device with high refrigeration efficiency can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing a conduction cooling type superconducting electromagnet apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conduction cooling type superconducting electromagnet device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Superconducting coil 2 Coil reel 3 Magnetic shield part 4 Radiation shield part 5 Shield part 7 Through hole 8 Heat transfer support rod 9 Container 10 Electromagnet part 11 First stage 12 Second stage 13 Current lead 14 Copper current lead 20 Refrigerator 21 First stage 22 Second stage 23 Terminal 30 Vacuum container 31 Container bottom 40 Magnetic flux

Claims (2)

[Scope of utility model registration request] 1. A refrigerator having a first stage portion for cooling the first stage and a second stage portion for cooling a second stage above the first stage; and a refrigerator on the second stage. And a current lead extending from the lower end of the second stage through the first stage and electrically connected to the electromagnet unit having a superconducting coil. In a conduction cooling type superconducting electromagnet apparatus provided with a magnetic shield portion for selectively shielding, the conduction cooling type superconducting electromagnet apparatus is characterized in that the electromagnet portion is covered with the second stage by a shield portion that also serves as a magnetic shield and a radiation shield. Superconducting electromagnet device. 2. The conduction cooling type superconducting electromagnet apparatus according to claim 1, wherein the shield part is supported by a heat conducting support rod provided on the first stage. Electromagnetic device.