JP3065988B2 - Normal conduction type bending electromagnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a normal-conducting beam bending electromagnet, and more particularly to a synchrotron radiation (hereinafter referred to as SR).
The present invention relates to a normal-conduction beam deflection electromagnet used in a generator.

[0002]

2. Description of the Related Art An SR light generating device extracts SR light from a predetermined position by moving electrons (including positrons) at a speed close to the speed of light along a predetermined orbit. Various types are provided. In particular, there is a strong demand for miniaturization of this type of apparatus, and an apparatus having an orbital radius of about 0.5 m has been put to practical use.

FIG. 11 shows a schematic configuration of an SR light generator using an electron storage ring called a race track type. An arc-shaped orbit having a curvature R is formed by the two bending electromagnets 51a and 51b, and the two arc-shaped orbits are connected by two linear orbits so that a race-track-type orbit 50 is provided in the vacuum vessel.
Is formed. In addition to the four first quadrupole electromagnets 52a, 52b, 52c and 52d, the four second quadrupole electromagnets 53a, 53b, 53c and 53d, and the RF acceleration cavity 54, A beam incidence kicker electromagnet 55 is arranged at the incidence portion.

An electron beam produced by an incidence accelerator (not shown) is introduced into a vacuum chamber from a beam introduction unit 56, and the RF acceleration cavity 54 and the bending electromagnets 51a,
The trajectory 50 is accelerated or deflected at a desired curvature at 51b.
Orbits at a speed close to the speed of light.

FIGS. 12 and 13 show examples of a conventional bending electromagnet. FIG. 12A is a plan view of a part of the bending electromagnet,
FIG. 12B shows a cross section along a straight line B12-B12.

As shown in FIG. 12A, a coil 63 is wound so as to surround a magnetic pole 61 formed in an arc shape.

[0007] As shown in FIG.
A gap 64 in which an electron orbit is to be formed is formed between them. Around magnetic pole 61 and coil 63, magnetic pole 61,
Yoke 62 for forming magnetic path 65 with gap 64
Is arranged.

When the magnetic flux density becomes stronger than the saturation magnetization of the magnetic pole, the magnetomotive force required for the coil sharply increases. In the bending electromagnet having the shape shown in FIG.
The magnetic flux density in the portion close to 2 becomes the highest, and as the magnetomotive force increases, the saturation of the magnetization proceeds from this portion.

FIG. 13 shows a case where a coil is wound also around the gap of the bending electromagnet of FIG. FIG. 13 (A)
FIG. 13B is a plan view of the bending electromagnet, and FIG.
13 shows a section along 13.

The magnetic pole 71, the yoke 72, the coil 73a and the gap 74 correspond to the magnetic pole 61, the yoke 62 and the coil 6 shown in FIG.
3 and a gap 64. The difference from FIG. 12 is that a coil 73b is wound around the gap 74. The magnetomotive force is increased by the coil 73b, and the uniformity of the magnetic field distribution in the gap 74 is improved.

The method shown in FIG. 13 is particularly effective for an electromagnet having a large gap 74. However, in this configuration, S
Since the R light cannot be extracted, it cannot be used for forming an electron storage ring that extracts and uses the SR light.

[0012]

The bending electromagnet includes a superconducting magnet and a normal conducting magnet. Among them, the superconducting type can generate a strong magnetic field, but if peripheral equipment is included, the superconducting type is inevitably complicated and large. further,
High technology is required for manufacturing, and the number of manufacturing steps is large, resulting in high manufacturing costs.

On the other hand, in the normal conduction type, the saturation magnetization of iron constituting the electromagnet is at most about 2.15 Tesla, and the magnetomotive force required to generate a magnetic flux density of 2.15 Tesla or more is required. Increases rapidly. for that reason,
It is usually used below 2.15 Tesla.

The radius of the orbit of the bending electromagnet of the SR device is determined by the magnetic field. For this reason, the normal-conducting type has a limit in miniaturization of the electron storage ring due to the above-described restriction of the strength of the magnetic field as compared with the superconducting type.

An object of the present invention is to provide a normal-conduction type deflection electromagnet that can generate a strong magnetic field using a normal-conducting electromagnet and reduce the orbital radius of the electron storage ring.

[0016]

According to one aspect of the present invention, a pair of magnetic poles provided to face each other with a gap to generate a magnetic field therebetween, and a magnetomotive force wound around the pair of magnetic poles, respectively. A pair of coils for generating, a yoke joined to each of the pair of magnetic poles to form a closed magnetic path with the gap, and control means for flowing a current to the pair of coils; At least one side surface along the direction of the magnetic path extends from the end on the yoke side such that the magnetic pole width at the junction with the yoke is wider than the width of the magnetic pole surface opposed across the gap. And the coil has a cross-sectional shape along the side surface of the corresponding magnetic pole, and the control means determines that the magnetic flux density of the magnetic pole near the junction with the yoke is 2.15. Below Tesla, Normal conducting deflection electromagnet magnetic flux density between the pair of magnetic pole electric current to the coil so that the above 2.7 Tesla is provided.

[0017]

The saturation of the magnetization in the vicinity of the yoke can be reduced by gradually increasing the cross-sectional area of the magnetic pole from the gap to the yoke. Thereby, in a state where the magnetic flux density in the vicinity of the yoke portion is suppressed to 2.15T or less,
The normal conducting coil can generate a magnetic field having a magnetic flux density of about 3T in the gap.

By forming the cross-sectional shape of the coil along the inclined side surface of the magnetic pole, the leakage magnetic field from the magnetic pole can be shielded by the coil to minimize the leakage magnetic field.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An outline of an embodiment of the present invention will be described with reference to FIGS.

FIG. 1A is a plan view of a part of the bending electromagnet.
FIG. 1B shows a cross section along a straight line B1-B1.

As shown in FIG. 1B, a pair of magnetic poles 1 are arranged with a gap 4 in which an electron storage ring is formed. At the tip of each magnetic pole, a Rogowski-shaped pole tip 1a is provided to make the magnetic field in the gap 4 uniform. Around the magnetic pole 1, a coil 3 is wound in an arc shape as shown in FIG. Control means 5 is connected to the coil 3, and a predetermined current flows through the control means 5.

Further, as shown in FIG.
The yoke 2 is disposed so as to surround the coil 1a and the coil 3, and a magnetic path is formed by the magnetic poles 1 and 1a, the gap 4, and the yoke 2. The coil 3 is wound all over the side surface along the magnetic path direction of the magnetic pole except for the Rogowski-shaped portion at the tip.

The magnetic pole width of the magnetic pole 1 increases as it approaches the yoke 2 from the gap 4. Therefore, the saturation of the magnetic flux density in the vicinity of the yoke of the magnetic pole 1 can be reduced. In order to increase the cross-sectional area of the coil 3, it is preferable that the cross-sectional shape of the coil 3 be along the side surface of the magnetic pole 1. Forming the cross-sectional shape of the coil 3 along the side surface of the magnetic pole 1 also has the effect of shielding the leaked magnetic field from the magnetic pole 1 with the coil 3 to minimize the leaked magnetic field.

FIG. 2 shows an example in which the side surface of the magnetic pole shown in FIG. 1 on the inner peripheral side of the electron storage ring is perpendicular to the magnetic pole surface facing the gap 4, and the yoke is arranged only on the outer peripheral side of the electron storage ring. . FIG. 2A is a plan view of a part of the bending electromagnet, and FIG.
(B) shows a cross section along the straight line B2-B2.

When the radius of curvature of the bending electromagnet is small,
Since the cross section perpendicular to the magnetic path is originally small on the inner circumference side of the magnetic pole, even if the slope on the inner circumference side of the ring is inclined, the effect of relaxing the magnetization saturation is small.

Therefore, in the example shown in FIG. 2, almost the same effects as in FIG. 1 can be obtained. For the yoke, the ring inner peripheral side portion is also removed for the same reason.

Next, the principle of the embodiment of the present invention will be described with reference to FIGS. FIG. 7 shows the excitation characteristics of iron. The horizontal axis represents the strength of the magnetic field in units of Oersted, and the vertical axis represents the magnetic flux density in units of Tesla. When the magnetic flux density is 2.15 Tesla or less, the magnetic flux density sharply increases as the magnetic field increases. However, when the magnetic flux density is 2.15
Above Tesla, it exhibits characteristics substantially similar to the excitation characteristics in air. That is, it has the same magnetic resistance as in air. Therefore, it has been generally considered that a superconducting coil should be used when a strong magnetic field is required so that the magnetic flux density in iron becomes 2.15 Tesla or more.

The inventor has found that by devising the shape of the bending electromagnet, it is possible to generate a magnetic flux density of about 3 Tesla using a normal conducting coil within a practical range of power consumption.

In the following discussion, the excitation characteristics of iron are idealized and approximated as follows. That is, the saturation magnetic flux density of iron Bs = 2.15T, the magnetic field strength H = 0 when the magnetic flux density is Bs or less, and the magnetic field strength H = when the magnetic flux density is Bs or more.
B-Bs. Here, the magnetic permeability in air is set to 1 for simplification.

First, a case where the side surfaces of the magnetic poles of the deflecting magnet are inclined will be considered with reference to FIG.

FIG. 8A is a partial sectional view of a quarter of the magnetic pole of the deflection magnet. The magnet was assumed to be infinitely long in the direction perpendicular to the page. The pole has a pole face parallel to the X 'axis,
It is symmetric about the Y 'axis. Further, the other magnetic pole is arranged at a position symmetric with respect to the X 'axis. As shown in FIG. 8A, the height of the gap is 2 h, the width of the gap is 2 w, and the angle formed between the side surface of the magnetic pole and the magnetic pole surface is θ.

For the sake of simplicity of calculation, as shown in FIG. 8B, it is assumed that the lines of magnetic force in the air are oriented in the Y direction and the magnetic flux density in the iron is uniform in the X direction.

Consider a coordinate system in which the intersection point between the side surface of the magnetic pole and the magnetic pole surface is the origin O. The side of the pole is the extension of the pole face (X
Axis) with respect to (axis). The height y on the side surface is expressed as y = x × tan (θ) (1). Here, tan (θ) = a.

The magnetic flux Φ (y) in iron at the height y is obtained by approximating the magnetic flux density in the gap between the magnetic pole faces to B ₀ , and the magnetic flux density in air to be a function of only x and B _air (x). , is given by _{Φ (y) = B 0 w} + ∫ 0 x B air (x) dx ··· (2). Here, the integration range is x satisfying the expression (1).
Up to.

When the magnetic field in iron is averaged in the X direction and approximated to be a function of only y, the magnetic flux density B in iron
_iron (y) is expressed as B _iron (y) = Φ (y) / (w + x) (3)

In the range where B _iron ≧ Bs, the magnetic potential Ψ (y) in iron is given by Ψ (y) = B ₀ h + ∫ ₀ ^y (B _iron (y) −Bs ) Dy (4)

When the magnetic potential 鉄 (y) in iron is expressed by focusing on the side surface region of the magnetic pole, Ψ (y) = B _air (x) × (h + y) (5)

By solving equations (2) to (5) using equation (1), B _air (x) = B ₀ -1 / 2 × Bs × ln (x / w + 1) +1/2 × Bs × (1- (1-h / a / w) ^-2 ) × (ln ((1 + x / w) / (1 + x / (h / a))) + (wh / a) (a / h-1 / (x + h / a))) ・ ・ ・ (6) B _iron (y) = B ₀ -1 / 2 × Bs (1-h / a / w) ^-2 (ln (1+ y / a / w) -y / (aw + y)) -1 / 2 × Bs (1- (1-h / a / w) ^-2 ) (ln (1 + y / h) -aw / h × y / (aw + y)) ・ ・ ・ (7) Ψ (y) = B ₀ h + (B ₀ -Bs) y-1 / 2 × Bs (1-h / a / w) ^-2 ((y + 2aw) ln (1 + y / a / w) -2y) -1 / 2 × Bs (1- (1-h / a / w) ^-2 ) × ((y + h) ln (1 + y / h ) − (1 + aw / h) y + a ² w ² / h × ln (1 + y / a / w)) (8)

Here, in the equation (4), B _iron <Bs
In the range, the magnetic potential に な る (y) becomes a constant. In Expression (7), if B _iron (y) <Bs is satisfied, at y that satisfies this, iron is unsaturated, and the magnetic potential becomes a constant.

Assuming that y that satisfies B _iron (y) = Bs is ys, the magnetic potential Ψ (ys) at this point becomes the magnetomotive force required to generate the magnetic flux density B _{0 in the} gap.
That is, the magnetic flux density in a region where the height of the magnetic pole is ys or more is 2.15T or less. In this manner, by providing the side surfaces of the magnetic poles with an inclination, it is possible to generate a magnetic field having a saturation magnetic flux density or higher in the gap portion in a state where iron does not reach saturation magnetization on the yoke side of the magnetic poles.

FIG. 9 shows a gap height of 4 cm (h = 2c).
m), when the saturation magnetic flux density (Bs) of iron is 2.15 Tesla, the change in magnetomotive force required to generate a magnetic flux density B ₀ of 2.7 Tesla in the gap with respect to the angle θ is shown.
The curves p1, p2, p3, and p4 each represent a half width w of the pole face.
Shows the required magnetomotive force when is 7 cm, 10 cm, 15 cm, and 20 cm.

When the angle θ is 60 ° or more, the required magnetomotive force increases remarkably. Also, as the half width w of the pole face increases, the required magnetomotive force also increases.

When the magnetic permeability of iron is infinite, the distance between the magnetic poles is
When half the height h of the gap is 2 cm, the magnetic flux density is 2.7 te.
Magnetomotive force required to generate slur is 5.4 Tcm
/ Μ _airThat is, 43200 ampere turns. This
Where μ_airIndicates the magnetic permeability of air. Empirically space, electricity
Due to the limitations of the source, etc., a bending electromagnet using a normal conducting coil
The magnetomotive force that can be generated realistically is 10^FiveAmpere
Turn, that is, up to about 12.5 T · cm.

Considering that equation (8) includes an error due to approximation, it is preferable to design the magnetic poles so that the required magnetomotive force is 10 T · cm or less. Therefore, from FIG. 9, the magnetic pole half width w needs to be 20 cm or less, and the angle θ needs to be 60 ° or less. When the angle θ is reduced, the magnetic pole becomes larger, and accordingly, the whole magnet becomes larger.
Is realistically about 30 °. Further, when the width of the pole face is reduced, the effective magnetic field region disappears and the electron orbit cannot be controlled. Therefore, the width of the pole face is preferably 4 cm or more.

When the height of the gap between the magnetic poles is increased, the magnetomotive force required to generate the same magnetic flux density increases almost in proportion to the height of the gap, so that the height of the gap cannot be increased too much. A realistic value is that half the height h of the gap is 3 cm or less.

The electron orbit vibrates at a constant amplitude in the height direction of the gap. In order to form a stable electron orbit, it is necessary to suppress this amplitude to 1/10 or less of the height of the gap. However, since it is difficult to suppress the amplitude to 1 mm or less, the height of the gap is preferably 1 cm or more.

When only one of the side surfaces is inclined, the half width of the pole face is preferably set to 10 cm or less.

Next, a case where the side surfaces of the magnetic poles are formed in a step shape will be considered with reference to FIG.

FIG. 10A is a partial sectional view of a quarter of the stepped magnetic pole. The magnet was assumed to be infinitely long in the direction perpendicular to the page. The magnetic pole is symmetric with respect to the Y axis, and the other magnetic pole is arranged at a position symmetric with respect to the X axis. As shown in FIG. 10A, the height of the gap between the magnetic poles is 2h (h represents half of the height), the magnetic pole width of the gap portion is 2w (w represents the magnetic pole half width), and the stepped portion Has a step height h ₁ and a width w ₁ . The coil is wound from the side of the narrow pole portion to the side of the wide pole portion.

For the sake of simplicity of calculation, as shown in FIG. 10B, it is assumed that the direction of the lines of magnetic force in air and iron is in the Y direction, and the magnetic flux density in iron is uniform in the X direction. Under this assumption, so that the magnetic flux density changes discontinuously at and below the plane of Y = h + h _1. In reality, the magnetic flux density does not change discontinuously, but in portions other than the vicinity of the discontinuity plane, this assumption is considered to be close to the actual state of the magnetic field.

In a region where y is h + h ₁ or more and the magnetic pole width is wide, the magnetic flux density is equal to or less than the saturation magnetic flux density of iron. The magnetic flux density at the gap between the magnetic poles is B ₀ , and the saturation magnetic flux density of iron is Bs
Then, the magnetic potential Ψ _{1 in a} region where y is h + h ₁ or more and the magnetic pole width is wide becomes a constant, and is expressed as Ψ ₁ = B ₀ h + (B ₀ −Bs) h ₁ (9).

[0052] This magnetic potential, when the magnetic flux density generated in the gap stepped portion and _{B 1, B 1 = Ψ 1} / (h + h 1) = (B 0 h + (B 0 -Bs) h 1) / ( h + h ₁ ) (10)

Since the magnetic flux density B _{0 in the} gap region between the magnetic poles and the magnetic flux density B _{1 in} the gap in the stepped portion on the yoke side enter the iron, the magnetic flux Φ _{1 in} the wide magnetic pole region is Φ ₁ = B ₀ w + B ₁ w ₁ (11) Therefore, the average magnetic flux density B _iron is as follows: B _iron = Φ ₁ / (w + w ₁ ) = (B ₀ w + B ₁ w ₁ ) / (w + w ₁ ) = (B ₀ w + w ₁ (B ₀ h + (B ₀ -Bs) h ₁ ) / (h + h ₁ )) / (w + w ₁ ) = B ₀ -Bsw ₁ h ₁ / (h + h ₁ ) / (w + w ₁ ) ・ ・ ・(12)

Since this magnetic flux density is equal to or less than the saturation magnetic flux density of iron, it is necessary to satisfy B ₀ -Bsw ₁ h ₁ / (h + h ₁ ) / (w + w ₁ ) <Bs (13) There is. Rewriting this formula, the _{w 1 h 1 / (h +} h 1) / (w + w 1)> B 0 / Bs-1 ··· (14).

Since the left side of the above equation is 1 or less, FIG.
It can be seen that the magnetic flux density B ₀ that can be generated in the shape (A) is not more than twice (2Bs) the saturation magnetic flux density. In order to generate a stronger magnetic flux density, it is necessary to increase the number of steps or combine it with a method of inclining the magnetic pole side surfaces. A method of increasing the number of stairs can be considered equivalent to approximating the inclination by the stairs.

As a design example to which the equation (14) is applied, h =
Assuming that 2 cm, h ₁ = 8 cm, and w = w ₁ , B ₀ / Bs
<1.4, ie, B ₀ <3.01T. B ₀ = 2.
Assuming 7T, the required magnetomotive force Ψ is 9.8T from equation (9).
Becomes Therefore, this example can be said to be a magnet that can be realized using a coil of a practical size.

Next, the results of numerical analysis of the embodiment of the present invention will be described with reference to FIGS. 3 to 6
The magnetic field lines obtained by numerical analysis of a bending electromagnet having a shape designed based on the above considerations will be described.

The bending electromagnets shown in FIGS. 3 to 6 all have x =
It is rotationally symmetric about 0. The return yoke is provided only on the outer peripheral portion, and is not provided on the inner peripheral portion because the sectional area is small and the effect is small. Fig. 5 (B)
It is almost the same except for. The generated magnetic flux density is 2.7 T at the center of the gap between the magnetic poles.

FIG. 3A shows a typical conventional bending electromagnet. Both ends of the magnetic pole tip have a Rogowski shape in order to make the magnetic flux density in the gap between the magnetic poles uniform.
In this case, the magnetomotive force required to generate a magnetic flux density of 2.7 T is 1.84 × 10 ⁵ amp turns, which is far beyond a practical 10 ⁵ amp turns.
It is difficult to realize.

FIG. 3B shows a case where the outer peripheral side surface of the magnetic pole is inclined at 60 ° with respect to the gap surface. In this case, the required magnetomotive force is 1.35 × 10 ⁵ ampere turns, and the required magnetomotive force is reduced as compared with the conventional example of FIG. However, it is still larger than the practicable magnetomotive force.

FIG. 3C shows a case where both sides of the magnetic pole have a 60 ° inclination angle. The required magnetomotive force is 1.04
It becomes × 10 ⁵ ampere turns, which is reduced to a practically usable magnetomotive force.

FIG. 4A shows a case where both side surfaces of the magnetic pole have a 45 ° inclination angle. The required magnetomotive force is 9.4x
This is 10 ⁴ amp turns.

FIG. 4B shows a case where the tip of the magnetic pole is formed in two steps. The required magnetomotive force is 9.9 × 10 ⁴
This is an ampere-turn, and substantially the same effect as in the case of FIG. 3C can be obtained.

FIG. 4C shows a case in which the tip of the magnetic pole is formed in a two-step shape, and furthermore, both ends of the second horizontal portion are inclined. The required magnetomotive force is 8.9 × 10 ⁴ amp turns, which can be further reduced.

FIG. 5A shows a case in which the tip of the magnetic pole is formed in a two-step shape and the outer periphery of the horizontal portion of the second step is inclined only. The required magnetomotive force is 8.7 × 10
⁴ amp turns.

FIGS. 5B and 5C show the case where the inclination of the outer peripheral portion in FIG. 5A is extended to the base of the magnetic pole. FIG.
The cross-sectional area of the coil of FIG. 5B is smaller than that of FIG. The required magnetomotive force is approximately 8.3 × 10 ⁴ amp turns, and there is almost no effect of reducing the cross-sectional area of the coil.

FIG. 6A shows a case where the slope portion of FIG. 5C is approximated by multiple steps. The required magnetomotive force is 8.8
× 10 ⁴ ampere turns, which is slightly increased as compared with the case of FIG. This is because the effective pole width has decreased.

FIG. 6B shows a case where the side surface of the step-like portion at the tip of the magnetic pole in FIG. 5C is inclined at 45 ° and is continuously connected to a Rogowski shape at the tip of the magnetic pole. . The required magnetomotive force is 8.0 × 10 ⁴ amp turns, which can be further reduced.

FIG. 6 (C) shows a case where the stepped portion is eliminated and a slope having an angle of about 37 ° is continuously connected to the Rogowski shape at the tip of the magnetic pole. By further reducing the tilt angle, the required magnetomotive force is 7.7 × 10 ⁴ amp turns, which can be further reduced. However, by reducing the inclination angle, the size of the magnetic pole and the entire magnet increases.

As can be seen from the results of the numerical analysis described above, by modifying the shape of the magnetic pole, it is possible to generate a magnetic field having a magnetic flux density of 2.7 T within a practically usable magnetomotive force by using a normal electroconductive magnet. Can be.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0072]

As described above, according to the present invention,
Using a normal conducting coil, a strong magnetic field having a magnetic flux density of about 3T can be obtained. This makes it possible to manufacture a small-sized electron storage ring at low cost.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view of a bending electromagnet according to an embodiment of the present invention.

FIG. 2 is a plan view and a sectional view of a bending electromagnet according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a bending electromagnet for illustrating a state of magnetic flux by numerical analysis in the bending electromagnet according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a bending electromagnet for illustrating a state of magnetic flux by numerical analysis in the bending electromagnet according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view of a bending electromagnet for illustrating a state of magnetic flux by numerical analysis in the bending electromagnet according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view of a bending electromagnet for illustrating a state of magnetic flux by numerical analysis in the bending electromagnet according to the embodiment of the present invention.

FIG. 7 is a graph showing the excitation characteristics of iron.

FIG. 8 is a partial sectional view of a magnetic pole for explaining the principle of the embodiment of the present invention.

9 is a graph showing a change in magnetomotive force required for generating 2.7T with the magnetic pole of FIG. 8 with respect to an angle θ.

FIG. 10 is a partial sectional view of a magnetic pole for explaining the principle of another embodiment of the present invention.

FIG. 11 is a schematic plan view of a race track type SR light generator.

FIG. 12 is a plan view and a cross-sectional view of a conventional bending electromagnet.

FIG. 13 is a plan view and a cross-sectional view of a conventional bending electromagnet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic pole 1a Magnetic pole tip part 2 Yoke 3 Coil 4 Gap 5 Control means 50 Orbit 51a, 51b Bending electromagnet 52a-52d, 53a-53d Quadrupole electromagnet 54 RF acceleration cavity 55 Beam incidence kicker 56 Beam introduction part 61 Magnetic pole 62 Yoke 6363 Coil 64 Gap 65 Magnetic path 71 Magnetic pole 72 Yoke 73a, 73b Coil 74 Gap

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-74595 (JP, A) JP-A-4-6799 (JP, A) JP-B-44-7227 (JP, B1) JP-B-39 14131 (JP, B1) Hiroo Kumagai, “Experimental Physics Course 28 Accelerator,” New Edition, 2nd edition, Kyoritsu Shuppan Co., Ltd., June 10, 1982, pp. 366-371 (58) .Cl. ⁷ , DB name) H05H 13/04 G21K 1/093 H01F 7/06 H05H 7/04

Claims (3)

(57) [Claims] A pair of magnetic poles provided so as to face each other with a gap to generate a magnetic field therebetween; a pair of coils wound around the pair of magnetic poles to generate a magnetomotive force; A yoke joined to each of the magnetic poles to form a closed magnetic path together with the gap, and a control unit for causing a current to flow through the pair of coils; at least one side surface along the direction of the magnetic path of the magnetic pole; The cross-sectional shape of the coil is inclined from the end on the yoke side to the magnetic pole surface so that the magnetic pole width at the joint with the yoke is wider than the width of the magnetic pole surface opposed to the gap. Has a shape along the side surface of the corresponding magnetic pole, and the control means determines that the magnetic flux density of the magnetic pole near the junction with the yoke is 2.15 Tesla or less, and between the pair of magnetic poles. Has a magnetic flux density of 2. A normal-conduction type bending electromagnet which supplies a current to the coil so as to be 7 Tesla or more. 2. The inclined side surface of the magnetic pole extends along an inclination angle of 30 ° or more and 60 ° or less with an extension of the magnetic pole surface, and the width of the magnetic pole surface is 4 cm or more and 20 cm or less, The normal conduction type bending electromagnet according to claim 1, wherein a height of the gap along a magnetic path is 1 cm or more and 6 cm or less. 3. At least a part of both side surfaces along a magnetic path direction of the magnetic pole is inclined so that a magnetic pole width at a joint portion with the yoke is wider than a width of a magnetic pole surface opposed to the yoke with the gap interposed therebetween. And, along a plane having an inclination angle of 30 ° or more and 60 ° or less with the extension of the pole face, the width of the pole face is 4 cm or more and 40 cm or less, and the height of the gap along the magnetic path is 1 cm. The normal-conduction type bending electromagnet according to claim 1, which is at least 6 cm or less.