JP3324748B2 - Magnetic field variable magnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field variable magnet for adjusting a magnetic field strength in a predetermined magnetic field space.
In particular, the present invention relates to a variable magnetic field magnet that can be used to deflect charged particles, such as a deflection magnet in a synchrotron.

[0002]

2. Description of the Related Art A charged particle deflecting device for deflecting charged particles moving by a strong magnetic field is indispensable to a device for handling charged particles, and includes an ion beam irradiation device, an electron beam processing device,
It is used in mass spectrometers and other advanced devices such as synchrotrons and free electron laser devices. In a charged particle deflector, it is necessary to adjust the magnetic field intensity according to operating conditions such as required deflection angle and charged particle energy. For this reason, it is preferable that the deflecting device that forms the magnetic field is of a variable magnetic field type that can easily adjust the intensity of the generated magnetic field. In particular, in a device such as a synchrotron which handles high energy charged particles, a magnetic field variable magnet which generates a sufficiently strong magnetic field and which can easily adjust the magnetic field is required.

Conventionally, the most frequently used deflection magnet is a deflection electromagnet in which a coil is attached to each of iron cores opposed to each other across a magnetic field space, and a magnetic field is generated in a gap between the iron cores by energizing the coils. is there. Bending electromagnets are easy to control because the magnetic field strength is adjusted by the coil current, but a large power supply is required because a large coil current is required to generate a strong magnetic field, and a large-diameter electric wire must be laid. . Further, an advanced cooling device is required to suppress thermal expansion of the coil. In addition, a large current is required during the operation of the electromagnet, and the operation cost is high. There is also known a variable magnetic field deflection magnet that utilizes a magnetic field generated between opposed permanent magnets and changes the gap between the permanent magnets to adjust the magnetic field strength. Such a method using a permanent magnet can provide a large magnetic field strength, but has a drawback that the magnetic field distribution state changes by changing the gap between the permanent magnets.

On the other hand, Japanese Patent Application Laid-Open No. 10-012432 discloses
The publication discloses a variable magnetic field magnet that adjusts a magnetic field generated in a fixed gap by rotating a cylindrical permanent magnet fitted in a part of an annular magnetic yoke having a fixed gap, and changes a magnetic field distribution. There is disclosed an apparatus in which the magnetic field intensity is adjusted without using the magnetic field. However, the magnetic field variable magnet disclosed in this publication does not have a sufficient intensity of the generated magnetic field, and when a strong magnetic field is required, it is necessary to use a plurality of magnetic circuits in combination. There is a disadvantage that it becomes complicated.

As shown in FIG. 10, the variable magnetic field magnet disclosed by the applicant in Japanese Patent Application No. 11-077236 has a pair of opposed cores facing each other across a magnetic field space, and a pair of opposed cores adjacent to each other. In a magnetic circuit formed by including the permanent magnets arranged in series, an adjustment gap is provided,
The magnetic field intensity in the magnetic field space is adjusted by changing the size of the gap.
In the magnetic field variable magnet of this configuration, a magnetic field is formed by the iron core excited by the permanent magnet, so that a sufficiently strong magnetic field strength can be obtained, and the magnetic field strength can be adjusted without changing the gap between the opposed iron cores forming the magnetic field space. The adjustment does not change the magnetic field distribution. However, the direction in which the magnetic field is generated between the permanent magnet and the opposing core, or between the cores,
That is, there is a problem that a large driving force is required to move the two in a direction in which they are attracted by the magnetic force, and a space for installing the magnet is increased by an amount necessary for the movement.

[0006]

The problem to be solved by the present invention is to have a sufficiently strong magnetic field strength and
An object of the present invention is to provide a magnetic field variable magnet that can easily adjust the magnetic field intensity without changing the magnetic field distribution and has a small installation space.

[0007]

In order to solve the above-mentioned problems, a magnetic field variable magnet according to the present invention comprises a first opposing core, and a second opposing core facing the first opposing core with a core gap therebetween. A first permanent magnet arranged such that a magnetic pole having a first polarity contacts and slides on a side surface of the first opposed core; and a second permanent magnet different from the first polarity on a side surface of the second opposed core. A second magnetic pole having a polarity of
Adjusting the magnetic field strength by moving one or both of the first and second permanent magnets in a direction that changes the distance from the core gap along the side surface of each opposing core. It is characterized by.

According to the magnetic field variable magnet of the present invention, a magnetic field is formed in the gap between the opposed cores by the core excited by the permanent magnet, so that the permanent magnet has a sufficiently strong magnetic field strength. The magnetic field strength can be adjusted without changing the distribution state of the magnetic field in the magnetic field space because the magnetic flux density is adjusted by adjusting the magnetic resistance in the magnetic circuit by moving along the permanent magnet and the permanent magnet and the opposing core Since the permanent magnet is moved in a direction perpendicular to the direction in which the magnetic field is generated, the permanent magnet can be moved with a small driving force. In a magnetic circuit formed in series including a pair of opposed cores facing each other across the magnetic field space, and a permanent magnet arranged to be sandwiched adjacent to each of the opposed cores, one or both of the permanent magnets are provided. Along the opposing core in a direction that changes the distance from the gap between the opposing cores that form the magnetic field space,
The magnetic field strength in the magnetic field space is adjusted.

The first and second permanent magnets may be composed of a pair of permanent magnets facing each other with the first and second opposed cores interposed therebetween. With this configuration, the intensity of the magnetic field formed in the iron core gap is further increased. Note that a reinforcing core may be provided on an end surface of the permanent magnet opposite to the end surface in contact with the opposing core. The presence of the reinforcing iron core can suppress the leakage of the magnetic field and increase the strength of the magnetic field generated in the gap between the opposing iron cores. Further, a magnetic flux absorbing yoke may be provided on the end face of the opposite core opposite to the core gap. Since the magnetic flux is distributed between the magnetic circuit passing through the magnetic flux absorbing yoke and the magnetic circuit passing through the iron core gap, the magnetic field intensity generated in the gap between the opposed iron cores can be greatly changed by slightly moving the permanent magnet, The installation space for the magnetic field variable magnet can be reduced. Furthermore, a shim for improving the flatness of the magnetic field may be provided on the facing surface of the facing core.

A gap on the magnetic circuit may be provided in the middle of the opposed core. To reduce the amount of magnetic flux flowing in the direction opposite to the core gap between the opposing cores, it is possible to increase the magnetic field strength in the core gap where the desired magnetic field is formed, and to move the permanent magnet to change the magnetic field strength The width can be further reduced. Further, a magnetic field forming coil may be wound around the opposing iron core to superimpose a magnetic field by the electromagnetic coil. With this configuration, the intensity of the magnetic field generated by the permanent magnet can be finely adjusted by adjusting the coil current. Further, the opposing iron core and the permanent magnet may be formed in a plate shape having an equal thickness or a sector shape in cross section, and a laminated magnetic layer may be formed to form a magnetic field space having a desired shape. A charged particle deflecting device according to the present invention uses the above-described variable magnetic field magnet to deflect charged particles.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings. FIG. 1 is a sectional view showing a configuration of a first embodiment of a magnetic field variable magnet according to the present invention.
2 is a cross-sectional view showing the configuration of the second embodiment, FIG. 3 is a cross-sectional view showing another embodiment of these embodiments, FIG. 4 is a graph illustrating the effect of the embodiment of FIG. 3, and FIG. 6 and 7 are graphs illustrating the effects of the embodiment of FIG. 5, FIG. 8 is a cross-sectional view illustrating the configuration of the fourth embodiment, and FIG. 9 is a fifth embodiment. FIG.

[0012]

Embodiment 1 This is an embodiment of the basic form of the present invention. As shown in FIG. 1, the basic configuration of the magnetic field variable magnet of the present embodiment is such that a pair of opposed cores fixed at the center, that is, a first opposed core 1 and a second opposed core 2, The permanent magnets are arranged adjacent to the iron core so as to sandwich the core from both sides, that is, the first permanent magnets 3 and 4 and the second permanent magnets 5 and 6. The permanent magnets are arranged such that ends having opposite polarities face the iron core in the first opposing core 1 and the second opposing iron core 2, and an end having the same polarity for one opposing iron core. The part is arranged so as to face the iron core. There is a predetermined gap F between the opposed iron cores 1 and 2.

In the magnet device having the above structure, the first iron core 1-the gap F between the iron cores-the second iron core 2-the second permanent magnet at the lower right in the figure-the first permanent magnet at the upper right in the figure 3- The first core 1 and the closed first magnetic circuit, and the first core 1-
Gap F-second iron core 2-lower left second permanent magnet 6-upper left first permanent magnet 4-first iron core 1 and closed second magnetic circuit. Iron core 1-gap F-second
And are formed by sharing the iron core 2. The direction of the magnetic flux flowing through the magnetic circuit is determined by the direction of the polarity of the permanent magnet. This magnetic circuit generates a target magnetic field in the gap F sandwiched between the iron cores.

The first permanent magnets 3 and 4 are connected to the first opposing core 1
, The second permanent magnets 5 and 6 can move along the side surface of the second opposed core 2 in a direction that changes the distance from the gap F. In the state where the permanent magnet is closest to the gap F as shown in FIG. 1A, the magnetic resistance of the magnetic circuit is reduced and the magnetic field intensity in the gap F becomes maximum, and as shown in FIG. As the distance from the gap F increases, the magnetic resistance of the magnetic circuit increases and the magnetic field intensity generated in the gap F decreases. Therefore, the magnetic field strength of the gap F can be adjusted by moving each of the first permanent magnets 3, 4 and the second permanent magnets 5, 6 to an appropriate position. If the adjustment range of the magnetic field strength may be small, only one set of permanent magnets, for example, the first permanent magnets 3 and 4 may be moved and the second permanent magnets 5 and 6 may be fixed.

The magnetic field variable magnet of the present embodiment uses a permanent magnet having a higher magnetomotive force than an electromagnet, so that the strength of the magnetic field formed in the gap between the iron cores can be sufficiently increased. Further, by using a plurality of permanent magnets in series and parallel, the magnetic field can be further enhanced. Further, the magnetic field intensity in the gap between the iron cores can be easily adjusted by adjusting the resistance of the magnetic circuit by moving the permanent magnet. When the permanent magnet is moved for adjustment, it is moved along the surface of the opposed core, so that the change in the magnetic field intensity generated at the contact portion between the permanent magnet and the iron core is small, so that it can be moved with a small driving force. This not only saves energy required for driving, but also enables highly accurate adjustment.

Further, since the opposed iron core is fixed and can be adjusted without changing the shape of the iron core gap, there is a feature that the distribution state of the magnetic field does not change even if the magnetic field intensity changes. Therefore, even if the magnetic field strength is changed in accordance with the change in the operating conditions, the change in the parallel magnetic field range is small, so that the adjustment of the arrangement is unnecessary and the adjustment is easy. Since the moving direction of the charged particles can be deflected by passing the orbit of the charged particles through the iron core gap of the variable magnetic field magnet of this embodiment, the magnet can be used as a charged particle deflecting device such as a synchrotron.

[0017]

Embodiment 2 The magnetic field variable magnet of this embodiment is different from the first embodiment in that a reinforcing core is further provided on the end face of the permanent magnet opposite to the end face adjacent to the opposing iron core, and the magnetic field space of the opposing iron core is provided. A yoke for absorbing magnetic flux is provided on the end face opposite to the end face facing. For the sake of simplicity, only portions different from the first embodiment will be described in detail. The components having the same functions as those in the first embodiment are denoted by the same reference numerals.

Referring to FIG. 2, the variable magnetic field magnet according to the present embodiment has opposed cores 1 and 2 of permanent magnets 3, 4, 5 and 6.
Iron cores 7, 8, 9, 10 for reinforcing the magnetic field are provided on the end face opposite to the end face adjacent to. By attaching this reinforcing iron core, leakage of magnetic flux can be prevented, and the intensity of the magnetic field generated in the gap F between the opposed iron cores can be increased. Further, magnetic flux absorbing yokes 11 and 12 are provided on the end faces of the opposed iron cores 1 and 2 opposite to the end faces facing the gap F, respectively.

In the magnet device having this configuration, the magnetic circuit that returns from the permanent magnet, which is relatively small in the first embodiment, to the opposing iron core through the outer space affects the magnetic field in the iron core gap F. That is, in addition to the first and second magnetic circuits described in the first embodiment, the first opposing iron core 1-the right flange in the drawing and the right iron core 7 in the magnetic flux absorbing yoke 11
A first permanent magnet 3 on the right side; a first opposed core 1 and a closed third
Magnetic circuit and first opposing iron core 1-yoke 11 for magnetic flux absorption
In the drawing, left flange-left iron core 8-left first permanent magnet 4
A first opposing core 1 and a closed fourth magnetic circuit, and a second opposing core 2-a second permanent magnet 5 on the right side 5-an iron core 9 on the right side 9-
Right side flange of magnetic flux absorbing yoke 12-second opposed iron core 2, closed fifth magnetic circuit, second opposed iron core 2-left second permanent magnet 6-left iron core 10-left side of magnetic flux absorbing yoke 12 A flange-second opposed iron core 2 and a closed sixth magnetic circuit, that is, a total of six magnetic circuits are formed. The direction of the magnetic flux flowing through any of the magnetic circuits is determined by the polarity of the permanent magnet.

The first permanent magnets 3 and 4 are arranged along the first opposed core 1, and the second permanent magnets 5 and 6 are arranged along the second opposed core 2.
It can move in a direction to change the distance from the iron core gap F. FIG.
As shown in (a), when the permanent magnet is closest to the gap F, among the six magnetic circuits, the other four magnetic circuits passing through the magnetic flux absorbing yoke have the maximum magnetic resistance, and the first magnetic circuit has the first magnetic circuit.
And the second magnetic circuit, that is, the magnetic resistance of the two magnetic circuits passing through the gap F decreases. as a result,
The magnetic field strength in the gap F is maximized. On the other hand, as shown in FIG. 2B, the permanent magnets 3, 4, 5, and 6 were moved away from the gap F,
When the magnetic fluxes are approached to the magnetic flux absorbing yokes 11 and 12, respectively, the magnetic resistances of the four magnetic circuits passing through the magnetic flux absorbing yokes decrease, and the magnetic resistances of the two magnetic circuits passing through the gap F increase. The intensity of the magnetic field generated at the time decreases.

In the variable magnetic field magnet of the present embodiment, the magnetic resistance of the four magnetic circuits passing through the magnetic flux absorbing yokes 11 and 12 changes greatly. Since the magnetic resistance of the two sets of magnetic circuits decreases and increases, the magnetic field strength of the gap F can be adjusted with a larger width for the same amount of movement of the permanent magnet. Therefore,
In this embodiment, in addition to the effects obtained in the first embodiment, the gap F
Therefore, the moving width of the permanent magnet corresponding to the adjustment width of the magnetic field intensity generated at the time can be reduced, and the entire apparatus can be further miniaturized.

In these embodiments, the opposing iron cores 1 and 2 may be provided with appropriate projections (shims) to improve the flatness of the magnetic field formed. FIG.
FIG. 4 is a cross-sectional view showing a state in which a shim 13 is attached to the end face facing the gap F of FIG. 2, and FIG. 4 is a graph showing a distribution state of the magnetic field intensity in the gap between the opposed iron cores 1 and 2. In FIG. 4, the horizontal axis indicates the magnetic field strength, and the vertical axis indicates the distance in the direction along the gap surface. When the end face of the opposed core is flat, the magnetic flux density in the periphery decreases due to the influence of the leakage magnetic field, and as shown by the dotted line in FIG. Tend.

Therefore, for example, a shim 13 as shown in FIG.
By projecting inward from the end face of the opposing core,
As shown by the solid line in FIG. 4, it is possible to make the magnetic field distribution uniform over a wider area than when there is no shim, and to expand the use range. The shim for improving the magnetic field distribution may be provided so as to widen the end face of the opposed iron core in the width direction so as to expand the uniform magnetic field range.

[0024]

Embodiment 3 The magnetic field variable magnet of this embodiment is different from that of the second embodiment in that a gap on the magnetic circuit is provided in the middle of the opposed core. For the sake of simplicity, only parts different from the second embodiment will be described in detail. Components having the same functions as those in the first and second embodiments are denoted by the same reference numerals. Referring to FIG. 5, in the magnetic field variable magnet of this embodiment, the first opposing core is divided into 1a and 1b by a magnetic gap G1, and the second opposing core is divided into 2a and 2b by a magnetic gap G2. ing.
The magnetic gaps G1 and G2 are actually provided by sandwiching a non-magnetic material or the like in the middle of the opposed iron core. The effect of providing the magnetic gaps G1 and G2 is shown in FIGS.

FIG. 6 shows the magnetic gap G by taking the width of the magnetic gap on the horizontal axis and the maximum magnetic field strength in the iron core gap on the vertical axis.
1, the maximum magnetic field strength generated in the gap F between the opposed iron cores when the size of G2 is changed, that is, the permanent magnets 3, 4, 5, 6
Shows the change in the magnetic field strength when is closest to the gap F.
The maximum magnetic field strength generated in the gap F is such that as the width of the magnetic gap increases, the width of the magnetic gap becomes 0 (zero),
That is, the value rapidly increases from the value when no magnetic gap is provided. This is because the provision of the magnetic gap increases the magnetic resistance of the magnetic circuit passing through the magnetic flux absorbing yokes 11 and 12 and reduces the magnetic flux flowing therethrough, thereby increasing the magnetic flux flowing into the gap F.

FIG. 7 shows the maximum magnetic field intensity generated in the gap F when the permanent magnet is closest to the gap F, with the horizontal axis representing the moving distance of the permanent magnet from the gap and the vertical axis representing the magnetic field strength in the gap. In the embodiment 2 having no magnetic air gap and the present embodiment having a magnetic air gap,
The figure shows a change in the magnetic field strength in the gap F when the distance from the gap F is changed by moving the permanent magnet. Magnetic gap G1,
In the present embodiment in which G2 exists, the magnetic field strength decreases more rapidly at the same moving distance of the permanent magnet. Therefore, in the present embodiment, the moving width of the permanent magnet can be further reduced with respect to the same adjustment width of the magnetic field strength, and the entire apparatus can be further downsized.

[0027]

Embodiment 4 The magnetic field variable magnet of this embodiment is different from the magnetic field variable magnet of the second embodiment in that an exciting coil for forming a magnetic field is wound around a part of the opposing iron core, so that the permanent magnet is generated. The magnetic field strength can be finely adjusted. For the sake of simplicity, only parts different from the second embodiment will be described in detail. Components having the same functions as those in the second embodiment are denoted by the same reference numerals.

Referring to FIG. 8, the variable magnetic field magnet of the present embodiment has an exciting coil 14,
15 are wound. When a current is applied to the exciting coils 14 and 15, a magnetic flux due to the coil current appears in addition to the magnetic flux generated in the opposed cores 1 and 2 by the permanent magnets 3, 4, 5 and 6. The direction of the magnetic flux added by the exciting coil is determined by the direction of the coil current, and the amount of added magnetic flux is determined by the current. Therefore, fine adjustment of the magnetic field intensity in the iron core gap can be easily performed. For example, as shown in FIG. 8, by generating magnetism in the direction opposite to that of the permanent magnet, the magnetic field strength in the gap F can be reduced. In addition, when a current is passed in the opposite direction to the above, the magnetic field strength can be increased. Although the exciting coils 14 and 15 are provided near the magnetic flux absorbing yokes 11 and 12 in FIG.
It may be provided in any part of.

[0029]

Embodiment 5 In this embodiment, the opposing iron core and the permanent magnet in the magnetic field variable magnet of Embodiment 1 are formed in a plate shape, and by arranging them in parallel, a magnetic field space having an arbitrary shape can be formed. It was done. FIG. 9 is a top view showing a deflection magnet formed by arranging the magnetic field variable magnets of the present embodiment side by side. The lower facing portion is hidden and cannot be seen.
The magnetic field space formed by laminating the plate-shaped opposed cores 1 has an arc shape along the trajectory of the charged particles. The permanent magnets 3 and 4 are arranged so as to sandwich each of the opposing cores 1.
The magnetic field strength is adjusted by moving the permanent magnet up and down along the side of the iron core.

The magnetic field variable magnet of this embodiment can be formed in any shape depending on the degree of overlap with the adjacent opposing iron core. In the case of forming an arc, the cross-sectional shape of the opposed core may be a sector shape. Similarly, also in the case of the second to fourth embodiments, a deflection magnet having a magnetic field space of a desired shape can be obtained by forming opposing iron cores, permanent magnets, and the like into a plate shape having an equal thickness or a sector shape and laminating them. it can. In each of the above embodiments, a pair of permanent magnets is used so as to sandwich the iron core. However, it goes without saying that the permanent magnets may be provided only on one side surface of the iron core.

[0031]

As described above, the variable magnetic field magnet of the present invention can form a strong magnetic field space.
Moreover, the magnetic field strength can be easily adjusted without changing the magnetic flux distribution state. Therefore, when the present invention is applied to a charged particle deflecting device that needs to adjust the magnetic field every time the operating state is changed, the preparation for operation is easy and the driving operation can be simplified. In adjusting the magnetic field strength, the permanent magnet is moved in a direction perpendicular to the direction of the magnetic force, so that the energy required for driving can be saved and highly accurate adjustment can be performed, and the magnetic flux absorbing yoke and the magnetic air gap can be adjusted. By adopting, the moving width of the permanent magnet can be reduced, and the installation space of the entire equipment can be reduced. Furthermore, since the magnetic field space can be formed into an arbitrary shape by using a magnetic field variable magnet which can be formed side by side, the magnetic field variable magnet of the present invention can be used in an electron storage ring, etc. to streamline manufacturing. It is possible to easily cope with a condition change during operation.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of a magnetic field variable magnet according to the present invention.

FIG. 2 is a sectional view of a magnetic field variable magnet according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of these examples.

FIG. 4 is a graph illustrating an effect of the embodiment of FIG. 3;

FIG. 5 is a sectional view of a third embodiment of the magnetic field variable magnet according to the present invention.

FIG. 6 is a graph illustrating the effect of the embodiment of FIG. 5;

FIG. 7 is a graph illustrating the effect of the embodiment of FIG. 5;

FIG. 8 is a sectional view of a magnetic field variable magnet according to a fourth embodiment of the present invention.

FIG. 9 is a top view of a magnetic field variable magnet according to a fifth embodiment of the present invention.

FIG. 10 is a perspective view showing a configuration example of a conventionally proposed magnetic field variable magnet.

[Explanation of symbols]

1, 2 opposed cores 1a, 1b, 2a, 2b opposed cores separated by magnetic gap 3, 4, 5, 6 permanent magnets 7, 8, 9, 10 cores 11, 12 magnetic flux absorbing yokes 13 shims 14, 15 Excitation coil F Gap G1, G2 Magnetic gap

Continuation of the front page (56) References JP-A-3-274710 (JP, A) JP-A-4-186804 (JP, A) JP-A-10-270197 (JP, A) JP-A-4-334899 (JP) JP-A-4-186805 (JP, A) JP-A-4-196110 (JP, A) JP-A-10-12432 (JP, A) JP-A-2000-277323 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) H05H 7/04 G21K 1/093 H01F 7/02 H05H 13/04

Claims (9)

(57) [Claims] 1. A first opposed iron core, and a first opposed iron core is opposed to the first opposed iron core with a core gap therebetween, and a relative position between the first opposed iron core and the first opposed iron core is changed.
A second opposing core that is not converted, a first permanent magnet arranged so that a magnetic pole having a first polarity contacts and slides on the side surface of the first opposing core, and a side surface of the second opposing core. A second permanent magnet arranged so that a magnetic pole having a second polarity different from the first polarity contacts and slides, and one or both of the first and second permanent magnets are provided as The shape of the core gap should not be changed by moving in a direction that changes the distance from the core gap along the side surface of each opposing core.
Field variable magnet and adjusting the magnetic field strength in the Ku iron center gap. 2. The magnetic field variable magnet according to claim 1, wherein each of the permanent magnets comprises a pair of permanent magnets opposed to each other with the opposed iron core interposed therebetween. 3. The magnetic field variable magnet according to claim 1, wherein each of the permanent magnets has a reinforcing core on an end face opposite to the opposing core. 4. The magnetic field variable magnet according to claim 1, wherein each of the opposed cores has a magnetic flux absorbing yoke on an end face opposite to the core gap. 5. At least one of the opposing iron core, wherein
It is fixed at a position sandwiching the permanent magnet with respect to the iron core gap.
2. An air gap on a magnetic circuit, wherein the air gap is provided.
5. The magnetic field variable magnet according to any one of items 1 to 4. 6. The magnetic field variable magnet according to claim 1, wherein a coil for forming a magnetic field is further wound around the opposed core. 7. The magnetic field variable magnet according to claim 1, wherein the opposed core has a protrusion in a gap between the cores to improve flatness of a magnetic field. 8. A magnetic field space having a desired shape is formed by forming the opposed iron core and the permanent magnet into a plate shape having an equal thickness or a sector shape in section and laminating them. 7. The magnetic field variable magnet according to any one of 7. 9. A charged particle deflecting device using the magnetic field variable magnet according to claim 1. Description: