JPH0779048B2 - How to connect saddle type superconducting magnet coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement in a method for connecting a saddle type superconducting magnet.

(Prior Art) Saddle-shaped superconducting magnet coils are used in the field of high energy physics, such as for deflecting charged particles in accelerators and the like. This saddle-shaped superconducting magnet coil is an outer layer coil (1) (1 ') having a semi-cylindrical cross section as shown in FIG. 4 (a).
And the inner layer coils (2) and (2 ') are vertically stacked to form a two-layer cylindrical shape. In this saddle type superconducting magnet coil, the superconducting wire used for each coil usually has different cross-sectional areas and dimensions in order to obtain desired superconducting characteristics such as a critical current value. Generally, the inner layer coil is exposed to a higher magnetic field than the outer layer coil. Since the critical current density of the superconducting wire decreases as the magnetic field increases, the cross-sectional area of the inner layer superconducting layer is larger than that of the outer coil superconducting wire.

In the superconducting magnet coil, the above-mentioned inner layer coil and outer layer coil are connected in series to form a magnet, but conventionally, a connecting wire was separately manufactured and connected. This connecting line
Since it is exposed to the same high magnetic field as the inner layer coil, its cross-sectional area is the same as that of the inner layer coil superconducting wire, and its width is the width of the outer layer coil superconducting wire so that it does not protrude from the radial thickness of the outer layer coil. It has been adapted to. That is, as shown in FIG. 4 (b), the outer layer coils (1) and (1 ') are connected to the inner layer coils (2) and (2') by connecting wires (3).
Using (3 '), (4) (4') and (5) (5 ')
At that time, they were connected by brazing, such as by soldering. However, in such a connecting method, as shown in FIG. 4 (c), the superconducting wire (6) of the inner layer coil (2 ') having a keystone cross section is connected to the connecting wire (3) with respect to the width (c). Since the width (c ') is small, the contact area between them cannot be made large, resulting in a large connection resistance, leading to power loss, and weak connection strength and gaps due to differences in width due to electromagnetic force. Since the movement of the wire is allowed, there is a problem that the stability of the characteristics of the superconducting coil is impaired.

(Means for Solving Problems) The present invention has been made to solve the above problems,
In the method of connecting a saddle type superconducting magnet coil in which the inner layer coil and the outer layer coil wound with superconducting wires with different cross-sectional dimensions are stacked and connected in series, the cross-sectional area of the connecting wire is equal to that of the inner layer coil. In addition, the method for connecting a saddle-shaped superconducting magnet coil is characterized in that the connecting wires are connected by making the width of the connecting wires equal to the superconducting wires of the inner layer coil and the outer layer coil.

That is, the present invention uses Nb ₃ Sn, compound superconducting wire such as V ₃ Ga or alloy superconducting wire such as NbTi having a keystone cross-section, which is wound into a racetrack to form a coil, which is then saddle-bonded by pressing or the like. In the so-called saddle-shaped superconducting magnet coil formed into a shape, when overlapping the inner layer coil and the outer layer coil and connecting the superconducting wire of the outer layer coil and the superconducting wire of the inner layer coil, the cross-sectional area of the connecting wire is set to the high magnetic field side. The connecting wire has the same cross-sectional area as that of the superconducting wire for the inner layer coil, and the width of the connecting wire is changed so that the width of the connecting wire is equal to the superconducting wire of the inner layer coil and the outer layer coil. To connect.

The reason why the cross-sectional area of the connection wire is equal to the cross-sectional area of the superconducting wire of the inner layer coil is that the connection part with the inner layer coil is also exposed to the same high magnetic field as the inner layer coil. This is because it is necessary to have equivalent critical current characteristics. Therefore, "equal" means "equal to or greater than" and may be slightly larger. Further, the width of the connecting wire is made equal to the width of the superconducting wires of the inner layer coil and the outer layer coil, because the width of the superconducting wire of both the inner layer and the outer layer does not contribute to the reduction of the connection resistance.

However, the above-mentioned connecting wire may be separately manufactured by swaging using the same material as the superconducting wire, and the superconducting wire of the inner layer coil having a large cross-sectional area is previously connected to the connecting portion in accordance with the width of the superconducting wire of the outer layer coil. The parts may be connected by being processed by swaging or the like.

(Example) An example of the present invention will be described below.

As shown in FIGS. 1 (a) and 1 (b), the superconducting wire made of Nb ₃ Sn has a wire material dimension A × B × C of 1.9 mm × 1.6 mm × 10 mm for the inner layer coil, and Wire size A '×
A superconducting wire (7) having B ′ × C ′ of 2.1 mm × 1.9 mm × 6 mm was used for the outer layer coil. The second superconducting wire for the inner layer coil
As shown in the figure, a saddle-shaped coil having an inner radius of 66 mm and an outer radius of 76 mm was formed into inner layer coils (2) and (2 '). Further, the superconducting wire for the outer layer coil was formed into a saddle type coil having an inner radius of 77 mm and an outer radius of 83 mm to obtain outer layer coils (1) and (1 '). Then, the ends of the inner layer coil and the ends of the outer layer coil were connected to the connecting wires (3) and (3 ') at the connecting portions (4), (4') and (5) (5 ') by soldering. As shown in FIGS. 3 (a) and 3 (b), the connecting wire (3) has a constant cross-sectional area, but one end has a thickness D of 1.76 mm and a width C of
It has a size of 10 mm and the other end has a thickness D'of 2.94 mm,
A wire having a width C'of 6 mm and having different dimensions is processed by swaging and bent as shown in (c). The width C of this connecting wire is equal to the width C of the superconducting wire (6) of the inner coil as shown in FIG. 1 (b), and the width C'of one wire is shown in FIG. 1 (a). ) Is equal to the width (c ') of the superconducting wire (7) of the outer layer coil.

In this way, by using a wire rod whose cross-sectional area is equal to the cross-sectional area of the inner layer coil in one connecting wire and has different dimensions at both ends to be the connecting portion, the superconducting wire having different dimensions in the inner layer coil and the outer layer coil The wires can be connected with the dimensions of the connecting portions perfectly matched.

According to the connection method of the present invention shown in FIG. 2 described above, the connection resistance at the inner layer coil connection portion is about as compared with the conventional connection wire having a constant cross-sectional dimension of 2.94 mm and a line width of 6 mm. It can be reduced to 3/5 and the calorific value can be reduced by about 0.1w. Since hundreds of superconducting magnets of this kind are installed on the orbit of the synchrotron accelerator, and the amount of electric power is said to be several hundreds w, there is a considerable reduction in the amount of electric power.

(Effect) As described above, according to the present invention, the cross-sectional area of the connecting wire is made equal to that of the superconducting wire of the inner layer coil, and the width thereof is made equal to the width of the superconducting wire of the inner layer coil and the outer layer coil. As a result, the movement of the wire rod due to the electromagnetic force is eliminated, and as a result, the connection resistance is reduced and the power loss is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a connecting portion of a connecting wire and a superconducting wire according to the present invention,
FIG. 2 is a cross-sectional view showing the connection state of the inner layer coil and the outer layer coil of the present invention, FIG. 3 is an explanatory view of the connection line of the present invention, (a) is a front view, (b) is a plan view, (c) 4A is a perspective view, and FIG. 4 is a view showing a conventional connection method. FIG. 4A is a perspective view of a saddle type superconducting magnet coil, FIG. 4B is a sectional view of a saddle type superconducting magnet, and FIG. It is sectional drawing of and a connection line. 1, 1 '... outer layer coil, 2 2' ... inner layer coil,
3, 3 '... Connection line 4, 4' ... Connection part 5, 5 '...
... Connecting part, 6, 6 '... Inner layer coil superconducting wire, 7, 7'
...... Outer layer coil superconducting wire

Claims (1)

[Claims] 1. A method for connecting a saddle type superconducting magnet coil, in which an inner layer coil and an outer layer coil wound with superconducting wires having different cross-sectional dimensions are superposed on each other and connected in series. A connecting method for a saddle type superconducting magnet coil, which is characterized in that the connecting wires are made equal to the superconducting wires and the widths of the connecting wires are made equal to the superconducting wires of the inner layer coil and the outer layer coil.