JPH08203697A - Electromagnet type circularly light-polarizing device - Google Patents

Abstract

PURPOSE: To efficiently form a magnetic field within a prescribed cavity for passing an electron beam, provide a light with higher luminance, and realize the downsizing. CONSTITUTION: In order to reduce the leakage flux generated between different magnetic pole parts (1-1a and 1-2a, and 1-2b and 1-3a) adjacently arranged in the advancing direction of electron beam, and a leakage flux reducing permanent magnet (4-1a, 4-1c, and 5-1a, 5-1c) having a magnetizing direction in the direction opposite to the direction of the leakage flux is effectively arranged within a limited space. Thus, the effective magnetic flux quantity within a prescribed cavity for passing the electron beam is substantially increased, and the improvement in magnetic filed intensity within the prescribed cavity is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an electromagnet-type circularly polarizing device called a wiggler or undulator used for an insertion type light source, a free electron laser, etc., and particularly, it is efficient in a predetermined space through which an electron beam passes. The present invention relates to an electromagnet-type circularly polarizing device having a structure that forms a magnetic field well.

[0002]

2. Description of the Related Art When an electron beam close to the speed of light passes through a magnetic field, it generates an electromagnetic wave, that is, synchrotron radiation light. When the electron beam is passed through a magnetic field whose magnetic field direction changes at a predetermined pitch and in a predetermined direction. , They interfere with each other to obtain light of higher brightness.

As a device for generating such synchrotron radiation, a so-called electromagnet type circular polarization device using an electromagnet as a magnetic field generation source as shown in FIG. 9 has been put into practical use. Normally, the number of magnetic field periods (N) is 2 depending on the polarization characteristics.
A type that can obtain N times as much light is called a wiggler, and a type that can obtain light with an intensity of N ² although the magnetic field is weaker than this and the amplitude of the electron orbit is extremely small is called an undulator.

The electromagnet-type circular polarization device shown in FIG. 9 has a one-period three-pole structure, and the facing directions of a pair of different magnetic pole portions which are opposed to each other with a predetermined gap therebetween are the traveling directions of the electron beam. Further, they are arranged so as to be displaced by 120 degrees in the circumferential direction at every pitch. More specifically, 1 is a plurality of cores (1-1, 1-2, 1-3 ...
1-n) are laminated and integrated to form a hexagonal tubular shape as a whole, and the excitation coil 2 is wound around each side (6 places) of the core assembly. . The exciting coils 2 are connected so that the magnetomotive forces of the coils adjacent to each other have opposite polarities.

Inside each core, a pair of magnetic pole portions (1-1a, 1-1b, 1) are formed so as to face each other with a predetermined gap 3 as shown in A, B and C of FIG. -2a,
1-2b, 1-3a, 1-3b ... 1-na, 1
-Nb) is formed. These cores (1-1, 1
, 2, 1-3 ... 1-n) are sequentially laminated in the traveling direction of the electron beam (Z direction in FIG. 9) such that the facing directions of the magnetic pole portions are displaced by 120 degrees. Make up 1. Three cores (1-1, 1 shown in A, B, C of FIG. 10)
One cycle (λw) is formed by laminating and integrating −2,1-3).

In such a structure, when a current is applied to each of the exciting coils 2, each core (1-1, 1-
2, 1-3-3 ... 1-n) has A in FIG.
Magnetic flux is generated in the directions indicated by arrows in B and C, and as a result, a pair of magnetic pole portions (1-1a and 1-1) in each core is generated.
b, 1-2a and 1-2b, 1-3a and 1-3b ...
Different magnetic poles are formed in 1-na and 1-nb), and a magnetic field in a predetermined direction is formed in the space between the different magnetic pole portions.

Therefore, a magnetic field whose magnetic field direction changes in a predetermined pitch and in a predetermined direction is formed in the substantially circular tunnel-shaped void 3 formed in the central portion of the core assembly 1, and the electron beam is generated in the magnetic field. Axial direction while rotating spirally (Z in Fig. 9
Direction) to generate the desired synchrotron radiation and obtain high brightness light.

[0008]

The electromagnet-type circularly polarizing device having the structure shown in FIG. 9 can realize the generation of the desired synchrotron radiation light. As is clear from the drawing, the synchrotron radiation light is formed in each core. A pair of different magnetic poles (1-1a
And 1-1b, 1-2a and 1-2b, 1-3a and 1-3b
... 1-na and 1-nb) are arranged adjacent to each other in the direction of travel of the electron beam, so that the magnetic flux generated between a pair of different magnetic pole portions facing each other with the gap 3 formed therebetween is generated. However, there is a problem that a large amount of magnetic flux leaks between different magnetic pole portions that are adjacent to each other in the traveling direction of the electron beam, and the efficiency is magnetically very low.

That is, as shown in FIG. 11, each magnetic pole portion (1-1a, 1-1b, 1-2a, 1-2b, 1-).
3a, 1-3b), focusing on the magnetic flux generated between the pair of different magnetic pole portions (1-1a and 1-1b, 1-2a and 1-2b, which are opposed to each other by forming the void 3). 1-
In addition to the magnetic flux generated between 3a and 1-3b), between different magnetic pole portions (for example, between 1-1a and 1-2b and between 1-2a and 1-3a) which are adjacently arranged at every pitch in the traveling direction of the electron beam.
Between the different magnetic pole portions (for example, between 1-1b and 1-3a) adjacent to each other in every pitch in the traveling direction of the electron beam (for example, between 1-1b and 1-3a). There is a broken line arrow in the figure), and according to the experiment of the inventor,
It was confirmed that 95% or more of the magnetic flux generated between the different magnetic pole portions was the leakage magnetic flux.

FIG. 12 is a development view showing a state of generation of leakage magnetic flux between the magnetic pole portions corresponding to the explanation of FIG. 11 (FIG. 1).
2 indicates the arrangement for two cycles), the solid line arrow in the figure is the leakage flux generated between different magnetic pole parts adjacently arranged at every pitch in the traveling direction of the electron beam, and the broken line arrow is the electron beam. It shows a leakage magnetic flux generated between different magnetic pole portions arranged adjacent to each other in every pitch in the traveling direction.

As is apparent from FIG. 12, a gap 3 is formed between a pair of different magnetic pole portions (1-1a and 1a) which are opposed to each other.
-1b, 1-2a and 1-2b, 1-3a and 1-3b
Distance between the different magnetic pole portions adjacent to each other at every pitch in the traveling direction of the electron beam (for example, 1-1a and 1-2b).
And between different magnetic pole portions (for example, between 1-1b and 1-3a) that are adjacently arranged at intervals of one pitch in the traveling direction of the electron beam and between the different magnetic pole portions (1-2b and 1-3a). It can be seen that leakage magnetic flux is easily generated.

Further, the exciting coil 2 which simply serves as a magnetic field generating source
Even if the magnetomotive force is increased, the core itself may cause magnetic saturation depending on the material of the core. For example, even if a permendur having a high saturation magnetic flux density is used for the core material, the magnetic field strength in the void 3 is increased. Was difficult to improve.

As described above, in the conventionally known electromagnet-type circularly polarizing device, since the structure in which the magnetic efficiency is essentially low is adopted, the strength of the magnetic field formed in the predetermined air gap is reduced. However, there is a limit to the brightness of light that can be obtained inevitably. In the configuration shown in FIG. 9, even if the material, size, shape, etc. of the core are variously improved, it is impossible to effectively improve the magnetic field strength in the void 3.

In view of the above situation, the present invention adopts the basic structure of a conventionally known electromagnet-type circularly polarizing device, while efficiently forming a magnetic field in a predetermined gap through which an electron beam passes. It is an object of the present invention to provide an electromagnet-type circularly polarizing device that can be used. Another object of the present invention is to provide an electromagnet-type circularly polarizing device that can obtain light with higher brightness than before. Further, it is an object of the present invention to provide an electromagnet-type circular polarization device that realizes downsizing of the electromagnet-type circular polarization device.

[0015]

As a result of repeating various experiments in order to achieve the above object, the present invention reduces the leakage magnetic flux generated between different magnetic pole portions arranged adjacent to each other in the traveling direction of the electron beam. Therefore, by effectively arranging a leakage flux reducing permanent magnet having a magnetization direction in a direction opposite to the direction of the leakage flux in a limited space, it is possible to substantially prevent the leakage of magnetic flux in a predetermined space through which the electron beam passes. It has been completed by finding that it is possible to increase the effective magnetic flux amount and to improve the magnetic field strength in the predetermined air gap.

That is, according to the present invention, a pair of different magnetic pole portions, which are opposed to each other with a predetermined gap formed therebetween, are arranged at a predetermined pitch in the traveling direction of the electron beam, and the facing direction of the pair of different magnetic pole portions is each pitch. In a plurality of electromagnet-type circularly polarizing devices that are arranged so as to be displaced by a predetermined angle in the circumferential direction, a pair of different magnetic pole portions facing each other are provided with a predetermined angle with respect to the circumferential direction on the circumferential outer circumferential portion. It is an electromagnet-type circularly polarizing device, characterized in that a leakage magnetic flux reducing permanent magnet having a magnetization direction in the direction is straddled.

As a preferred configuration, in the above configuration, the leakage flux reducing permanent magnet is substantially fan-shaped, and the magnetization direction is a constant angle with respect to the circumferential direction of each of the pair of different magnetic pole portions arranged to face each other. We also propose an electromagnet-type circularly polarizing device characterized in that As a more preferable configuration, the permanent magnet for reducing the leakage flux is substantially fan-shaped,
Further, the magnetizing direction is different in the vicinity of the contact surface between the pair of different magnetic pole portions and the central portion between the different magnetic pole portions with respect to the circumferential direction of the pair of different magnetic pole portions facing each other. We also propose a circular polarization device. Furthermore, in each of the above-mentioned configurations, an electromagnet-type circularly polarizing device is characterized in that a magnetic flux adjusting magnetic material is arranged in at least one of a pair of different magnetic pole portions arranged to face each other so as to be able to approach and separate from each other. .

[0018]

The operation of the electromagnet type circularly polarizing device of the present invention will be described with reference to FIG.
A description will be given based on an embodiment shown in FIG. Figure 1
FIG. 3 is a detailed perspective perspective view of a pair of different magnetic pole portions facing each other and forming a predetermined gap in the electromagnet type circularly polarizing device of the present invention. Only the different magnetic pole portions of are shown.

In the figure, reference numerals 4-1 and 5-1 denote a pair of different magnetic pole portions (1-1) which are opposed to each other with a predetermined gap 3 formed therebetween.
a ... N pole, 1-1b ... S pole), which are permanent magnets for reducing leakage flux, which are provided over the outer circumferential portion in the circumferential direction, each of which is substantially fan-shaped and has a magnetization direction in the direction of the arrow in the figure. have. 6-1 and 7-1 are permanent magnets 4 for reducing the leakage flux.
-1 and 5-1 is an arc-shaped fixed frame made of a non-magnetic material such as stainless steel, which is fixed to the permanent magnets and protects the permanent magnets. Such a pair of different magnetic pole portions (1-1a, 1-1)
The core having the magnetic flux leakage reducing permanent magnets (4-1, 5-1) and the fixed frame (6-1, 7-1) arranged in b) has a pair of magnetic poles sequentially in the traveling direction (Z direction) of the electron beam. The parts are laminated so that the facing directions of the parts are displaced by 120 degrees to form a core assembly, which constitutes the electromagnet-type circularly polarizing device of the present invention (see FIG. 9).

FIG. 2 is a developed view (FIG. 2 shows an arrangement for two cycles) in which the leakage magnetic flux reducing permanent magnets corresponding to the explanation of FIG. 1 are arranged. Is a permanent magnet for reducing magnetic flux leakage, and the solid line arrow in the permanent magnet indicates the magnetization direction. Here, comparing the development view of FIG. 2 showing the configuration of the present invention with the development view of FIG. 12 showing the conventional configuration, the magnetization direction of each permanent magnet for reducing magnetic flux leakage in FIG. ) And between different magnetic pole portions adjacent to each other at every pitch in the traveling direction of the electron beam in FIG. 12 (for example, between 1-1a and 1-2b and 1-2b).
It can be seen that the directions of the leakage magnetic flux generated between (1 and 3a) and (1-3a) are opposite directions.

Therefore, by arranging the leakage magnetic flux reducing permanent magnets having the magnetization directions as shown in FIGS. 1 and 2 at the predetermined positions of the pair of different magnetic pole portions arranged to face each other,
It is possible to reduce the leakage flux generated between different magnetic pole portions (for example, between 1-1a and 1-2b and between 1-2b and 1-3a) that are adjacently arranged at each pitch in the traveling direction of the electron beam. Become.

Further, in order to similarly reduce the leakage magnetic flux generated between the different magnetic pole portions which are adjacently arranged at intervals of one pitch in the traveling direction of the electron beam, in order to reduce the leakage magnetic flux, the leakage magnetic flux reduction structure having the structure shown in FIG. 3 is used. It is effective to arrange a permanent magnet. 4. FIG. 4 is a development view showing the arrangement configuration of the leakage magnetic flux reducing permanent magnets in FIG. 3 (FIG. 4 shows the arrangement for two cycles), and the hatched portion in the drawing shows the leakage magnetic flux reducing permanent magnets. The solid arrow in the permanent magnet indicates the magnetization direction. That is, the substantially fan-shaped leakage flux reducing permanent magnets 4-1 and 5-1 in FIG. 1 are each further divided into three in the circumferential direction, and the vicinity of the contact surface with the pair of different magnetic pole portions and the different magnetic pole portion are divided. The magnetization direction is different from that in the central portion.

As shown in the drawing, in the vicinity of the contact surface between the pair of different magnetic poles, between the different magnetic poles (for example, 1-1a and 1-2b) which are adjacently arranged mainly at every pitch in the traveling direction of the electron beam.
In order to reduce the leakage magnetic flux generated between the leakage magnetic fluxes (1-2b and 1-3a), the leakage magnetic flux reducing permanent magnets (4-1a, 4-) having a magnetization direction opposite to the direction of the leakage magnetic flux.
1c and 5-1a, 5-1c), and between the pair of different magnetic pole portions, between the different magnetic pole portions that are adjacently arranged mainly at intervals of one pitch in the electron beam traveling direction (for example, 1-1b and 1b). In order to reduce the leakage flux generated in (between -3a), a configuration is adopted in which leakage flux reducing permanent magnets (4-1b and 5-1b) having a magnetization direction opposite to the direction of the leakage flux are arranged. To do.

Therefore, by arranging the leakage magnetic flux reducing permanent magnets having the magnetization directions as shown in FIGS. 3 and 4 at the predetermined positions of the pair of different magnetic pole portions arranged to face each other,
Between different magnetic pole portions (for example, between 1-1a and 1-2b and between 1-2b and 1-3a) that are adjacently arranged at every pitch in the direction of travel of the electron beam, and at intervals of every pitch in the direction of travel of the electron beam. Between different magnetic pole parts to be arranged (for example, 1-1b and 1-3
It is possible to reduce the leakage magnetic flux generated between (a), substantially increase the effective magnetic flux amount in the predetermined air gap through which the electron beam passes, and realize the improvement of the magnetic field strength in the predetermined air gap. You can do it.

In the electromagnet-type circular polarization device of the present invention described above, when a current is applied to each of the exciting coils 2 similarly to the conventional electromagnet-type circular polarization device, each core (1
−1, 1-2, 1-3 ... 1-n) generate magnetic flux in the directions indicated by arrows in A, B, and C of FIG. 10, resulting in a pair of magnetic poles in each core. Section (1-1a, 1-
1b, 1-2a, 1-2b, 1-3a, 1-3b ... 1
Different magnetic poles are formed in (-na, 1-nb) (see FIG. 9), but the leakage magnetic flux is reduced in the circumferential direction outer peripheral portion of the pair of different magnetic pole portions in the direction of a predetermined angle with respect to the circumferential direction. The magnetic fluxes generated between the different magnetic pole portions are reduced by straddling the permanent magnets for use, and as a result, the effective magnetic flux in the substantially circular tunnel-shaped void 3 formed in the central portion of the core assembly 1 is reduced. By increasing the amount, a strong magnetic field whose magnetic field direction changes at a predetermined pitch and in a predetermined direction is formed in the void 3, and the electron beam passes through the magnetic field in the axial direction while rotating in a spiral shape. It is possible to generate synchrotron radiation and obtain high-intensity light.

Further, since the leakage flux reducing permanent magnets constituting the electromagnet type circularly polarizing device of the present invention are arranged so as to straddle a pair of different magnetic pole portions in each core, the permanent magnets are attached to the different magnetic pole portions. Further, as shown in FIGS. 1 and 3, the leakage flux reducing permanent magnets, the fixing frame, and the like are integrally fixed to each core, and these can be handled as one set. It has an advantage that the whole assembly is easy.

The overall configuration of these is shown in FIG. That is, FIG. 5 shows a pair of magnetic pole parts (1-1) shown in FIG.
a, 1-1b) is a permanent magnet for reducing magnetic flux leakage (4-1a,
4-1b, 4-1c and 5-1a, 5-1b, 5-1
c) and the fixed frame (6-1, 7-1) are integrally arranged as one set, and these sets are sequentially arranged in the advancing direction (Z direction) of the electron beam so that the facing direction of the pair of magnetic pole parts is 12
The core assembly is constructed by stacking so as to be displaced by 0 degree, and for example, a non-magnetic bolt (not shown) is passed through a fixed frame and tightened and fixed.

In FIGS. 1 to 5 described above, the opposing directions of the pair of different magnetic pole portions, which are opposed to each other with a predetermined air gap, are 120 ° in the circumferential direction at every pitch in the traveling direction of the electron beam. The polarities of the magnetomotive forces of the coils adjacent to each other are opposite to each side (six locations) of the core assembly that forms a hexagonal tubular shape by stacking and integrating a plurality of magnetic cores that are arranged so as to be displaced. The description has been given based on the electromagnet-type circular polarization device having a so-called magnetic flux confluence type one-cycle three-pole type configuration in which exciting coils connected to each other are wound and arranged.

As described above, the magnetic flux confluence type electromagnet-type circular polarization device in which each core of the core assembly is made of only a magnetic material and wound so that the polarities of the magnetomotive forces of the coils adjacent to each other are reversed. In this case, only the one-period odd-pole type structure is obtained. In addition to the above-mentioned one-period three-pole type, one-period five-pole type (the facing direction of the pair of magnetic pole portions is sequentially in the electron beam traveling direction (Z direction) However, in this case as well, the positional relationship of the different magnetic pole portions is shown in a developed view, and the leakage magnetic flux is generated according to the direction of the leakage magnetic flux generated between the different magnetic pole portions. By appropriately determining the magnetization direction and arrangement configuration of the reducing permanent magnet, the same operational effect as described above can be obtained.

As for the structure of the core assembly, each outer frame portion (side portion) other than the magnetic pole portion of the core has a hybrid structure of a magnetic substance and a non-magnetic substance, and a plurality of these cores are laminated and integrated. In a so-called magnetic flux recirculation type electromagnet circularly polarizing device having a configuration in which exciting coils connected to each side of a polygonal cylindrical core assembly so that the polarities of magnetomotive forces are in the same direction are wound and arranged. In addition to the one-cycle odd pole type structure, one-cycle even pole type structure can be obtained.

For example, in the case of a one-period quadrupole type electromagnet-type circular polarization device which is arranged so as to be displaced by 90 degrees in the circumferential direction at every pitch in the traveling direction of the electron beam, a development view shown in FIG. Based on the above, the magnetization direction and arrangement of the leakage flux reducing permanent magnet should be appropriately determined (the shaded portion in the figure is the leakage flux reducing permanent magnet, and the direction indicated by the arrow in the permanent magnet is the magnetization direction). Thus, it is possible to obtain the same operational effect as in the case of the one-cycle three-pole type.

Therefore, the permanent magnet for reducing magnetic flux leakage which constitutes the electromagnet-type circularly polarizing device of the present invention depends on the arrangement configuration (including shape, size, etc.) of different magnetic pole portions adjacent to each other in the traveling direction of the electron beam. , Their layout is shown in a developed view as shown in FIG. 12, the direction of the leakage magnetic flux generated between the different magnetic pole portions is confirmed, and the direction of magnetization is opposite to the direction of the leakage magnetic flux. By setting so that, the intended effect can be obtained.

Further, as the permanent magnet for reducing the leakage magnetic flux,
It is possible to use known magnet materials, but since the actual placement space is limited to some extent, rare earth /
It is preferable to use a rare earth magnet having excellent magnetic properties such as a cobalt magnet or a rare earth / iron / boron magnet. In particular, as shown in FIG. 7 (plan view), a permanent magnet for reducing leakage flux having a magnetizing direction at a predetermined angle with respect to the circumferential direction has a direction perpendicular to the thickness direction (arrow M direction in the drawing) in advance. )
After obtaining a fan-shaped anisotropic permanent magnet (indicated by a chain double-dashed line in the figure) having a magnetization direction at both ends of the anisotropic permanent magnet in the thickness direction and both ends in the direction perpendicular to the thickness direction. It can be easily obtained by subjecting the surface to polishing at a predetermined angle (in the figure, the hatched portion indicates a leakage flux reducing permanent magnet having a magnetization direction in the θ direction with respect to the circumferential direction).

The permanent magnet for reducing magnetic flux leakage in FIG. 1 is shown as an integrated product, but it is sufficient if it has the above-described magnetization direction as a whole, and it is divided into a plurality in consideration of workability and the like. It is also possible to assemble and integrate things. Similarly, the leakage magnetic flux reducing permanent magnet in FIG. 3 is also shown to have a three-divided configuration, but it may be divided into four or more in consideration of workability and the like.

Further, as the core which constitutes the electromagnet type circularly polarizing device of the present invention, it is decided to use the magnetic flux confluence type or the magnetic flux recirculation type depending on the number of poles in one period and the assembling property. A magnetic material or a non-magnetic material is selected. In particular, a known soft magnetic material can be used as the magnetic material, but in order to prevent magnetic saturation in the core, a permendur is used. It is desirable to select a material having a high saturation magnetic flux density such as. The configuration of the core assembly formed of the laminated body of these cores is not limited to the hexagonal tubular shape shown in FIG.
10 depending on the arrangement of the exciting coil that is the magnetic field source
A polygonal tubular shape such as a square tubular shape or a 14-sided tubular shape can be appropriately selected.

The electromagnet-type circular polarization device of the present invention shown in FIG. 8 is further improved to control the amount of magnetic flux generated from each magnetic pole portion to make the amount of magnetic flux generated from each magnetic pole portion uniform. This is an embodiment capable of obtaining more stable and high-luminance light.

More specifically, FIG. 8 shows an improved electromagnet-type circularly polarizing device having the structure shown in FIG. 5, which comprises a pair of permanent magnets (4-1a, 4-1b, 4-1c and 5- for reducing leakage flux). 1
a, 5-1b, 5-1c), a pair of fixed frames (6-1 and 7-1) arranged on the outer side are provided with notches 8 in the circumferential direction, and the notches 8 face each other. A female screw portion 9 is formed so as to penetrate toward the circumferential end surface portion of the pair of different magnetic pole portions (1-1a, 1-1b) to be arranged, and the pair of different magnetic pole portions ( (1-1a, 1-1b), a magnetic flux adjusting magnetic material 10 composed of a bolt member that moves so as to be able to move toward and away from each other is arranged on the circumferential end face portion.

In the above structure, for example, when the leakage magnetic flux adjusting magnetic material 10 is brought close to the circumferential end face portion of the magnetic pole portion (1-1a), the traveling direction of the electron beam from the magnetic pole portion (1-1a). Adjacent magnetic poles (1-
The amount of magnetic flux leaked to 2b) can be increased.

By disposing the control mechanism having such magnetic flux adjusting magnetic material 10 near each magnetic pole, it becomes possible to finely adjust the amount of magnetic flux leaking from each magnetic pole, and as a result, each magnetic pole can be adjusted. It is possible to make the amount of magnetic flux generated from the portion into the predetermined gap 3 uniform. However, these control mechanisms do not necessarily have to be attached to all magnetic pole portions, and may be arranged at least on one of a pair of different magnetic pole portions arranged facing each other according to the fine adjustment range of the leakage magnetic flux amount and the like.

As described above, various configurations can be adopted for the electromagnet type circularly polarizing device of the present invention, and the present invention is not limited to the illustrated embodiment, and a predetermined permanent magnet for reducing magnetic flux leakage is provided. The object of the present invention can be achieved by arranging effectively.

[0041]

EXAMPLE To confirm the operation and effect of the present invention, FIG.
The electromagnet of the present invention in which the conventional one-cycle three-pole type electromagnet type circularly polarizing device shown in FIG. 3 and the leakage magnetic flux reducing permanent magnet having a magnetization direction in a predetermined angle direction (constant direction) shown in FIGS. 1 and 2 are arranged. A circularly polarized light device of the present invention, and further, a leakage magnetic flux reducing permanent magnet in which the magnetization directions shown in FIGS. 3 and 4 are different between the vicinity of the contact surface between the pair of different magnetic pole portions and the central portion between the different magnetic pole portions. The electromagnet-type circularly polarizing device was prepared, and the magnetic field strength at the center of the gap was measured and compared. As the core material, permendur having a thickness of 2.6 mm was used, the distance between the pair of different magnetic pole portions facing each other was 4.6 mm, and the number of cycles was 10.

As the permanent magnet for reducing the leakage flux, an anisotropic sintered magnet of rare earth / iron / boron system having a maximum energy product (BH) max of 33 MGOe is used, and the thickness is 2.6 m.
m × outer diameter 15 mm × inner diameter 3 mm × inner angle 146 ° processed into a fan shape. Regarding the magnetization direction, the configuration shown in FIGS. 1 and 2 has an angle of 12.45 degrees with respect to the circumferential direction (see FIG. 2), and the configurations shown in FIGS. On the other hand, the one in the vicinity of the contact surface of the different magnetic poles has an angle of 12.45 degrees with respect to the circumferential direction, and the one in the center between different magnetic poles has an angle of 23.82 degrees with respect to the circumferential direction. Processed into.

The magnetic field strength at the center of the air gap in each electromagnet-type circularly polarizing device is 3 to 5 kG in the case of the conventional device, and 3 in the case of the device of the present invention adopting the configuration shown in FIGS. 1 and 2. In the case of the device of the present invention which employs the configuration shown in FIGS. 3 and 4, it is 3.6 to 6 kG. As is clear from the above results, it is possible to improve the magnetic field strength in the central portion of the air gap by 10% or more and 20% or more in the electromagnet type circularly polarizing device of the present invention as compared with the conventional device. .

[0044]

As described above, the electromagnet-type circular polarization device of the present invention is arranged adjacent to the electron beam traveling direction while adopting the basic structure of the conventionally known electromagnet-type circular polarization device. In order to reduce the leakage magnetic flux generated between the different magnetic pole portions, by effectively disposing the leakage magnetic flux reducing permanent magnet having a magnetization direction in a direction opposite to the direction of the leakage magnetic flux in a limited space, It is possible to provide an electromagnet-type circular polarization device capable of substantially increasing the effective magnetic flux amount in a predetermined air gap through which an electron beam passes, thereby improving the magnetic field strength in the air gap, and obtaining light of higher brightness than before. did. Further, if a magnetic field strength comparable to that of the conventional device is obtained, the device can be downsized.

[Brief description of drawings]

FIG. 1 is a detailed perspective perspective view of a pair of different magnetic pole portions that are arranged to face each other with a predetermined gap formed in an electromagnet-type circularly polarizing device according to an embodiment of the present invention. Only the pair of different magnetic pole portions are shown so that the arrangement configuration of FIG.

FIG. 2 is a development view of a configuration in which a leakage flux reducing permanent magnet corresponding to FIG. 1 is arranged (FIG. 2 shows an arrangement for two cycles).

FIG. 3 is a detailed perspective view of tips of a pair of different magnetic pole portions which are opposed to each other with a predetermined gap being formed in an electromagnet type circularly polarizing device according to another embodiment of the present invention, and particularly, a permanent magnetic flux leakage reducing permanent magnet. Only the pair of different magnetic pole portions are shown so that the arrangement of the magnets is clear.

FIG. 4 is a development view of a configuration in which a leakage magnetic flux reducing permanent magnet corresponding to FIG. 3 is arranged (FIG. 2 shows an arrangement for two cycles).

5 is an explanatory perspective view for assembling an electromagnet-type circularly polarizing device having the configuration of FIG.

FIG. 6 is a development view (FIG. 2 shows an arrangement for two cycles) in which a leakage magnetic flux reducing permanent magnet is arranged in an electromagnet type circularly polarizing device according to another embodiment of the present invention.

FIG. 7 is an explanatory plan view showing a method of processing a leakage flux reducing permanent magnet that constitutes the electromagnet-type circularly polarizing device of the present invention.

FIG. 8 is an assembly perspective view showing an electromagnet type circular polarization device which is another embodiment of the present invention.

FIG. 9 is a perspective explanatory view showing the outline of the overall configuration of a conventional electromagnet-type circularly polarizing device.

10 is an explanatory diagram showing an outline of each core that constitutes the electromagnet-type circularly polarizing device of FIG. 9. FIG.

FIG. 11 is a detailed perspective explanatory view of the tip of each magnetic pole portion in the electromagnet-type circularly polarizing device of FIG. 9.

FIG. 12 is a development view corresponding to FIG. 11 (FIG. 2 shows an arrangement for two cycles).

[Explanation of symbols]

1 core assembly 1-1, 1-2, 1-3 ... 1-n core 1-1a, 1-1b, 1-2a, 1-2b, 1-3a,
1-3b ... 1-na, 1-nb Magnetic pole part 2 Coil 3 Air gap 4-1, 4-1a, 4-1b, 4-1c, 5-1 and 5-
1a, 5-1b, 5-1c Leakage magnetic flux reducing permanent magnets 6-1 and 7-1 Fixed frame 8 Notch portion 9 Female screw portion 10 Leakage magnetic flux adjusting magnetic material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Hashimoto 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Sumitomo Special Metals Co., Ltd. Yamazaki Works

Claims (4)

[Claims] 1. A pair of different magnetic pole portions, which are arranged to face each other with a predetermined gap formed therebetween, at a predetermined pitch in the traveling direction of an electron beam.
Further, in a plurality of electromagnet-type circularly polarizing devices arranged such that the facing directions of the pair of different magnetic pole portions are displaced by a predetermined angle in the circumferential direction at each pitch, the pair of different magnetic pole portions facing each other are provided. An electromagnet-type circularly polarizing device, characterized in that a leakage magnetic flux reducing permanent magnet having a magnetization direction at a predetermined angle with respect to the circumferential direction is provided on the outer circumferential portion in the circumferential direction. 2. The leakage flux reducing permanent magnet is substantially fan-shaped, and the magnetizing direction is a direction at a constant angle with respect to the circumferential direction of each of the pair of different magnetic pole portions facing each other. The electromagnet-type circularly polarizing device according to claim 1. 3. The leakage magnetic flux reducing permanent magnet is substantially fan-shaped, and has a magnetization direction in the vicinity of the contact surface with the pair of different magnetic pole portions with respect to the circumferential direction of the pair of different magnetic pole portions arranged facing each other. 2. A portion and a central portion between different magnetic pole portions are different from each other.
Electromagnetic circular polarization device. 4. An electromagnet-type circular polarization device according to claim 1, wherein a magnetic flux adjusting magnetic material is disposed on at least one of the pair of different magnetic pole portions facing each other so as to be able to approach and separate from each other.