JPS63120405A - Deflecting electromagnet - Google Patents

Abstract

PURPOSE:To eliminate waste of magnetic flux, to control inductance and to obtain a charged particle beam deflecting electromagnet having improved rise characteristics, by providing, in an aperture of an iron core, two conductors having a U-shaped cross section such that they are opposed to each other. CONSTITUTION:A deflecting electromagnet of the present invention comprises an iron core 1 consisting of magnetic poles 2 and a yoke 3, a linear-section conductor 6 having a U-shaped cross section and opposed to said magnetic poles 2, and a winding conductor 7 and a leading conductor 8 connected to the ends of the linear-section conductor 6, respectively, outside of the iron core 1. For example, the cross section of the aperture 4 in the iron core 1 may be H-shaped and the width omegag of the aperture 4 is determined to be large enough to receive a vacuum duct inserted therein while the width omegap of the magnetic pole is determined such that magnetic field distribution as required can be ensured. Further, the cross section of the conductor 6 in the linear section of the coil 5 located within the iron core is U-shaped so that the two legs are opposed to each other and cover the inner surfaces of the yoke 3 except the magnetic poles 2. In this manner, a pulse electromagnet having a wide aperture and still having reduced inductance and improved magnetic field rising characteristics can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electromagnet for deflecting a charged particle beam, which is used in a particle accelerator or the like.

(Prior Art) In the field of particle accelerators, deflection electromagnets with particularly fast response, that is, pulsed electromagnets, are used for inputting, outputting, or distributing charged particle beams (hereinafter referred to as beams). These pulsed electromagnets are used, for example, to quickly build up a magnetic field while the beam goes around the ring, with a rise (or fall) time of about 10-8
~10-5 seconds is required. When such a pulse electromagnet is connected to a pulse generation power source and excited, the rise time τ of the current is given by the relationship 1 to T, where the circuit impedance is 2 and the inductance is L, so if τ is made small, In order to do this, the inductance L of the electromagnet must be made as small as possible.

FIG. 5 shows an example of a conventional pulsed electromagnet for beam deflection. The iron core (2) is composed of an electromagnetic part (2) and a return yoke part (2), and a one-turn coil (2) is installed between the electrodes in this iron core. This coil has a straight section 0. Consists of an end routing portion (■) and a drawer portion (■).

FIG. 6 shows a sectional view of FIG. 5. (between the magnetic poles of the iron core by energizing coil 0 placed on both sides inside the iron core)
Generates upward and downward magnetic fields.

FIG. 7 shows a cross-sectional magnetic flux line diagram based on numerical calculations.

(Problem to be solved by the invention) Since the inductance L is determined by the amount of magnetic flux Φ passing through the electromagnet, depending on this distribution, the magnetic flux density B is
1) is constant, then the magnetic pole cross-sectional area is S, LocΦ=BS, and the magnetic pole width is ω1, and the iron core is Q, then Φ=BS=B
QXω.

It is. Among these, ■3 and Q are values determined by the performance specifications of the electromagnet, but the magnetic pole width ω81, that is, the width of the iron core opening, is rather the value of the vacuum duct inserted into the electromagnet opening [(12 The lower limit is limited by the width ωd of )), so in terms of magnetic field performance, the width ω1
is often large.

As a result, the inductance 4 also increases, which is very inconvenient for the magnetic field characteristics of the electromagnet. This is because the current required to generate magnetic field B is 1
Then, the charging voltage ■ is given by V=2XZI. Therefore, from the above equation, τoCL/V. That is, for the same charging voltage V, if the inductance L is large, the rise of the magnetic field will be delayed, and conversely, a higher charging voltage is required to obtain the same magnetic field rise characteristics. As the charging voltage increases, the insulation of the entire system, including not only the electromagnet itself but also the power supply, becomes complicated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a charged particle beam deflection electromagnet that has excellent start-up characteristics by eliminating wasted magnetic flux and suppressing inductance.

[Structure of the invention]

(Means for Solving the Problems) The bending electromagnet of the present invention has two U-shaped U-shapes facing each other in the core opening, leaving only the magnetic field width ω1 necessary for magnetic field performance and covering the rest. Place the cross-sectional conductor.

(Function) With this configuration, the magnetic flux interlinking with the coil conductor is reduced and the inductance is reduced.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

Figure 1]-- shows an example of the structure of an electromagnet according to the present invention. The iron core 0) is composed of a magnetic pole ■ and a return yoke part (5) as in the conventional example shown in FIG. Similarly, it is large enough to insert a vacuum duct inside, but the magnetic pole width ω may be large enough to guarantee the necessary magnetic field distribution.The coil , as shown in the cross section of FIG. 2, have a U-shaped configuration facing each other so as to cover the inner surface of the yoke portion G3) except for the a-pole portion (3).

FIG. 3 shows a magnetic flux line diagram (Fig. 1, Part 4) in the cross section shown in FIG. 2. By setting the magnetic pole width ω1 to an appropriate value and arranging U-shaped conductors 0 on both sides, the magnetic flux can be narrowed down, and as a result, the magnetic flux density within the magnetic field usage range is B.
On the other hand, outside of this, a distribution of B(x)<Bo is formed. In this way, by limiting unnecessary magnetic flux, the total magnetic flux Φ can be reduced. Moreover, the conductor (0's 10, lower part ■) eliminates excess magnetic flux, and the side part (io) acts to adjust the magnetic flux, so the magnetic pole width is smaller than the conventional one. The magnetic flux density is aligned within the required range, and a nearly uniform magnetic flux density distribution can be obtained.

Therefore, in the electromagnet of this example, without changing the size of the opening for inserting the vacuum duct,
The inductance is small without impairing the magnetic field distribution characteristics within the required range, and therefore fast magnetic field rise characteristics can be obtained.

(Other Examples) In the above example, the shape of the core opening (A) is H-shaped, but the second side is rectangular (that is, the core shape is WF-
It becomes a window frame type. ), the same effect can be obtained. FIG. 4 shows a sectional view of this embodiment. As in the previous embodiment, the effective magnetic pole width ω2 is determined by the upper and lower portions of the U-shaped conductor (1), and the direction of the magnetic flux is aligned by the side portion (10). Moreover, since the iron core shape is simpler than the H-type, it is superior in terms of manufacturability.

〔Effect of the invention〕

As described above, according to the configuration of the present invention, since the U-shaped conductor is used, the amount of magnetic flux passing through the electromagnet is suppressed, and a large opening width is obtained.

Moreover, a pulsed electromagnet for deflecting a charged particle beam with small inductance and excellent magnetic field rise characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a bending electromagnet according to an embodiment of the present invention;
Figure 2 is a sectional view taken along the line ■-■ in Figure 1, Figure 3 is a cross-sectional magnetic flux distribution diagram of the same embodiment, Figure 4 is a configuration diagram of another embodiment, Figures 5, 6, and FIG. 7 is a perspective view, a sectional view, and a magnetic flux line diagram of a conventional bending electromagnet, respectively. 1... Iron core 2... Magnetic pole 3... Return yoke 4... Open [1 part 5... Coil
6...Coil straight part 9...Coil straight part upper/lower part 10...Coil straight part side part 11...Central plane 2nd figure

Claims (1)

[Claims] An iron core consisting of a magnetic pole part and a yoke part, a straight part conductor having a U-shaped cross section and arranged opposite to the magnetic pole part, and a routing connected to the end of this straight part conductor outside the iron core. A bending electromagnet characterized by comprising a conductor and a lead-out conductor.