JPS62262311A - Superconductor wire - 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 [Field of Industrial Application] The present invention relates to the structure of a superconducting wire with a large keystone angle that can be used in dipole magnets and the like.

[Conventional technology]

The proton synchroton, a particle accelerator for high-energy physics research, uses a dipole magnet to deflect the proton flux. This magnet usually has 5
The superconducting coil has an inner diameter of 0 to 200 m and is composed of rectangular shaped stranded wires with a trapezoidal or keystone cross section.

There are two conventional methods for winding the formed stranded wire, as shown in FIG. That is, (1) The first method involves winding several layers of superconducting wire 1b with a small keystone angle 2θ (shown in FIG. 4(a)) representing the slope of the formed stranded wire, as shown in the first quadrant of FIG. After the line, the center angles are adjusted using spacer No. 2 to improve the precision of the magnetic field in the Y-axis direction.

In this case, the structure of the superconducting wire 1b is as shown in FIG. 1I(a), in which a plurality of superconducting strands of ttl wires in which NbTi filaments are embedded in a Cu stabilizing metal are compressed and then insulated with tape or the like. The body is covered with the arm.

(2) The second method is to wind the superconducting wire 1c with a built-in spacer arrow in advance so that the chiston angle 2θ (shown in Figure q (b)) becomes large as shown in the first quadrant of Figure 5. It is. In this case, the structure of the superconducting wire IC is as shown in FIG. 4(b). After compressing a plurality of stranded superconducting elements m'+", tapered spacers 2 are applied from both sides to insulate the outside. The body is covered with the arm.

[Problem that the invention seeks to solve]

In recent years, the aforementioned proton synchroton has become more and more dog-shaped, and there has recently been a demand for the development of superconducting magnets with high magnetic fields of 5 to LOT class. In response to this tendency, with conventional wire winding methods, as detailed below, normal conduction transition tends to occur due to frictional heat due to wire movement during energization, and therefore, it is difficult to obtain a high magnetic field even though the number of training sessions is large. It was causing trouble.

That is, when winding the wire using the first method described above, conventionally it was not possible to obtain a large chiston angle, so when assembled into the structure shown in the first quadrant of Fig. 5, there was a large deviation from the arch structure, and It has a non-homogeneous structure with spacer arrows inserted into it. Therefore, the force in the X and Y directions is unbalanced and it is difficult to tighten the wires sufficiently from the outside, which tends to cause misalignment between the wires due to mechanical stress caused by heat shrinkage, etc.
In 2L), an electromagnetic force acts on the superconducting M1b, but no electromagnetic force acts on the spacer 2, so that the wire tends to shift with respect to the spacer. Furthermore, since the first method does not allow a large keystore angle, the inner diameter of the coil cannot be made very small even if spacers are inserted every few layers, and therefore the magnetic field distribution in the Y-axis and Z-axis directions is too small. It wasn't good.

In addition, when the wire is wound using the second method described above, the keystone angle becomes larger and the arch structure has a good balance against mechanical stress. In Figure (b), the superconducting strands 2 tend to be misaligned with respect to the spacer 2 due to electromagnetic force. Furthermore, since it has a complicated structure in which smooth wires are applied to both sides of each flat stranded wire, manufacturing is time-consuming and there are problems in terms of dimensional accuracy and the like.

[Means for solving problems]

The present invention was made as a result of intensive research to solve these problems, and is a keystone shaped stranded wire made by compressing multiple superconducting strands.
is 2t·n−+(α/N) or more, and the superconducting wire is characterized in that a spacer having a triangular or trapezoidal cross section is incorporated between the upper and lower strands of the cross section. However, N is the number of strands, and α is a constant in the range of 0, 5 to 10 depending on the type of superconducting wire.

[For production]

The present invention prevents movement of the wire due to mechanical stress and electromagnetic force by increasing the keystone angle and incorporating a spacer ax between the upper and lower wires in the cross section, This eliminates the normal conduction transition caused by frictional heat when moving the wire, making it possible to obtain a high magnetic field with less training.

In addition, by increasing the keystone angle, it became possible to reduce the inner diameter of the coil, resulting in better magnetic field distribution in the Y-axis and Z-axis directions.

In the present invention, the number of Ni wires (N25) and α are constants determined by the type of superconducting wire and the manufacturing process (normal Nb
For Ti line, α> O, lj, Wlnd and
For React type NtnSn wire, when α>1), the keystone angle 20 is 2 tan-' (α/N)
The above limitation is due to the fact that if it is less than 24n-' (α/N), there will be a large deviation from a perfect and homogeneous arch structure when winding rectangular stranded wire, and the wire will move when energized, resulting in training. This is because a high magnetic field cannot be obtained even if the number of times is increased. In addition to simply increasing the key store angle, a spacer is built in between the superconducting strands as shown in Figure 1, so that when the strands are subjected to centrifugal force due to electromagnetic force, the strands touch the spacer. It is necessary to prevent the wires from moving relative to each other, and if a spacer is not built in between the wires as shown in Figure 4(b), the wires may move. Misalignment will occur with respect to the spacer. Furthermore, by incorporating the spacer 6, it is possible to expect a cooling effect from the inside of the wire due to the spacer 6, and a reinforcing effect in the winding direction can also be expected. As a spacer*, an insulated copper wedge-shaped block similar to that shown in Fig. 1 (a) is usually used, but as shown in Fig. 1 (bl or Fig. 1 (c)
As shown in Figure 2, by bundling and compressing copper wires coated with a high-resistance substance or organic substance such as Keyproninogal, or by bending a copper tape coated with these to make it flexible. I can't even handle it.

〔Example〕

A superconducting wire in which a plurality of Nb-116, 5wt, %T1 alloy filaments were embedded in a copper stabilized metal was stranded and compressed to form a keystone-shaped superconducting wire, and this was wound to produce a superconducting coil. At this time, the spacer of the coil of the present invention was a copper tape coated with Keepronickel as shown in FIG. 1(C), and after being bent, it was formed using a Turk's head. Conventionally, an insulated copper wedge has been used as a spacer for the coil. The upper and lower coils of the inner layer and outer layer wound as described above were combined and fastened and fastened from the outside with glass fiber-containing resin to form a dipole coil with a length of 1 m. Table 1 shows the configurations of the present invention and conventional coils used in the experiment.

The conventional coil 1 corresponds to the one shown in FIG. 4(a) where the keystone angle is small, and the conventional coil 2 corresponds to FIG. 4(b) where the keystone angle itself is large.

These coils are installed vertically in the cryostat,
A current test was conducted after cooling with liquid nitrogen and liquid helium. The results are shown in Table 2.

As is clear from Table 2, when the coil of the present invention is used, the design characteristics of 6.5T are reached at the second energization after two training sessions, whereas the conventional coil shown in Table 1 In conventional examples 1 and ■ using Ui and Ui, 1
Even after 0 times of reverse energization, the design characteristics have not been reached.

〔Effect of the invention〕

The present invention has made it possible to obtain a high magnetic field with a small number of training sessions. In addition, the coil of the present invention has a good magnetic field distribution, and can be expected to have a cooling effect and a reinforcing effect on the spacer portion.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of the superconducting wire of the present invention, and FIG. 2 is a diagram showing the keystone angle range of the superconducting wire of the present invention. Fig. 5 is a cross section of the Guypor magnet winding part, and Fig. 4 is a diagram showing the structure of a conventional superconducting wire. 1a... superconducting wire, 1b... superconducting wire, IC...・
Superconducting wire, 2... Spacer, 5... Insulator, 4...
・Superconducting wire Figure 1 Element wire I! N Figure 2

Claims (2)

[Claims] (1) In a keystone-shaped stranded wire made by compressing multiple superconducting strands, the keystone angle 2θ is 2tan^-^
1 (α/N) or more, and is characterized by incorporating a spacer having a triangular or trapezoidal cross section between the upper and lower strands of the cross section. However, N is the number of strands, and α is a constant ranging from 0.3 to 1.0 depending on the type of superconducting wire. (2) The superconducting wire according to claim 1, wherein the spacer is composed of a group of thin wires or a thin plate of a high-conducting material coated with a high-resistance material.