JPS61267282A - Connection of superconductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a method for connecting superconducting wires.

[Prior art and its problems]

When creating superconducting magnets, connecting the superconducting wires is always a problem. For large magnets, the length of superconducting wire required can be several kilometers.

On the other hand, in terms of manufacturing, it is extremely difficult to obtain such long superconducting wires with consistent characteristics and without breakages during the manufacturing process.

In compound superconductors such as Nb3Sn, the characteristics are significantly degraded by stress and strain. Unfortunately, in producing a large magnet, it is disadvantageous to use long Nb 3 S n-rays as they tend to deteriorate their characteristics.

Recently, a method called pancake winding has been used in which superelectric magnets are created layer by layer and then connected.

As described above, connecting superconducting wires is a big problem, but no definitive method has been found yet.

FIG. 2 is a typical example of a conventional connection method.

(a) shows superconductor filament 1 and stabilizing material copper 2.
This is a method in which superconducting wires 3 made of the following are stacked on top of each other and directly soldered or welded. (b) is a method of soldering or welding through the core 4.

However, both methods have a problem in that resistance occurs because the superconducting core wire is discontinuous at the joint. This caused many difficulties in making magnets, and the development of superconducting applications was also hindered.

[Purpose of the invention]

It is an object of the present invention to overcome the above-mentioned drawbacks of conventional connection methods by using a laser.

[Summary of the invention]

The present invention removes the stabilizing material from the connecting portion of two superconducting wires to be connected, leaving only the filament of the superconductor, and then brings the filament-only portions of both superconductors into contact with each other. The gist of this is to irradiate the parts with a laser and connect them.

〔Effect of the invention〕

According to the present invention, inconveniences such as resistance generation and deterioration of characteristics due to Joule heat generation caused by the discontinuity of the superconducting core wire in the conventional superconducting wire connection portion can be eliminated.

[Embodiments of the invention]

An embodiment of the invention is shown in FIG.

(Example 1) As shown in FIG. 1(a), the Cu part of the connection part of the NbTf superconducting wire 3 in the stabilizer Cu matrix was removed with nitric acid, leaving only the NbTi filament l, and the part with only the NbTi filament. were caulked together and brought into contact, and the laser 5 was irradiated as shown by the arrow. The laser is N at the contact part.
To melt the bTi filament and solidify it rapidly,
A completely continuous superconducting wire is obtained. Furthermore, during laser irradiation, the superconducting wire 3 was rotated to ensure uniform connection.

(Example 2) As shown in FIG. 1(b)K, in the same manner as in Example (1), only the NbTi filament 1 was used as the connection portion, and then the NbTi filaments 1 were stacked and bundled, and the entire overlapped portion was irradiated with the laser 5.

At the same time, the superconducting wire 3 was rotated to ensure uniform connection.

(Example 3) As shown in FIG. 1(c), in the same way as in Example (1), only the NbTi filament 1 was used as the connection part, and these were stacked one on top of the other and connected by irradiating the laser 5.

After connecting with the above method, the part where only the NbTi filament is connected is processed by a method such as Cu electrodeposition and then Cu
It was stabilized by soldering and used in actual use.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a connection method according to the present invention, and FIG. 2 is a perspective view showing a connection method according to a conventional method. ■... Superconductor filament, 2... Stabilizing material,
3... Superconducting wire, 4... Core, 5... Laser. (b) Figure 2

Claims (1)

[Claims] After removing the stabilizing material from the connecting part of the two superconducting wires to be connected, leaving only the superconducting filament, the filament-only parts of both superconductors are brought into contact with each other, and a laser is applied to the contact part. A method for connecting superconducting wires, which is characterized by connecting by irradiation.