Horizontal and vertical polarization undulator

Abstract

Provided is a variable polarization undulator comprising an upper first magnet row 1 in which a large number of magnets are disposed in a row, an upper second magnet row 2 which is adjacent to the upper first magnet row 1 and in which a large number of magnets are disposed in a row, a lower first magnet row 3 in which a large number of magnets are diposed in a row, and a lower second magnet row 4 which is adjacent to the lower first magnet row 3 and in which a large number of magnets are disposed in a row, the upper first magnet row 1 and the upper second magnet row 2 being disposed facing the lower first magnet row 3 and the lower second magnet row 4 across a gap through which an electron beam moves, and the variable polarization undulator being characterized by comprising drive mechanisms 80, 90 that relatively move the upper first magnet row 1 and upper second magnet row 2 and the lower first magnet row 3 and lower second magnet row 4 in a horizontal direction orthogonal to the direction of travel of the electron beam.

Description

Horizontal and Vertical Polarization Undulator

[0001] The present invention relates to an undulator capable of switching between horizontal polarization and vertical polarization.

[0002] An undulator, as exemplified in Patent Document 1 below, includes a first magnet array in which a large number of magnets are arranged in a row, a first magnet support on which the first magnet array is attached and supported, a large number of magnets arranged in a row, and a second magnet array facing the first magnet array through a gap, a second magnet support on which the second magnet array is attached and supported, and a vacuum chamber in which the first magnet array, the second magnet array, the first magnet support, and the second magnet support are arranged. With this configuration, it is a device for generating a periodic magnetic field and extracting synchrotron radiation by causing the incident electrons to meander.

[0003] This undulator can change the intensity of light by changing the gap distance between the first magnet array and the second magnet array facing each other across the gap, but the polarization state of the synchrotron radiation is constant.

[0004] On the other hand, the undulator disclosed in Patent Document 2 below can switch the polarization state of the synchrotron radiation to left and right circular polarization, left and right elliptical polarization, or horizontal and vertical linear polarization. Such an undulator is generally known as an APPLE-II type undulator, and its configuration is schematically shown in FIG. 1A.

[0005] As shown in FIG. 1A, the upper first magnet array and the upper second magnet array are adjacently arranged across the gap, and the lower first magnet array and the lower second magnet array are adjacently arranged. The upper first magnet array and the lower first magnet array are arranged to face each other exactly across the gap, and the upper second magnet array and the lower second magnet array are also arranged to face each other exactly across the gap.

[0006] In this arrangement of magnet arrays, the upper first magnet array and the lower second magnet array, which are diagonally opposite each other, are fixed, while the upper second magnet array and the lower first magnet array, which are diagonally opposite each other, are driven horizontally (in the direction of electron beam propagation) as a pair. Figure 1B shows the state in which the pair has been moved horizontally by the width of one magnet in the magnet array, and Figure 1C shows the state in which the pair has been moved horizontally by the width of two magnets in the magnet array. This makes it possible to switch from horizontal polarization to circular polarization and then to vertical polarization.

[0007] JP 2019-175766 JP 5-303000

[0008] However, the above-mentioned variable polarization undulator has the following problems. Specifically, because it is necessary to drive the upper first and upper second magnet rows, which are adjacent to each other on the left and right, in a relative horizontal direction, a large magnetic force acts when driving the magnet rows, and its direction and strength change. The same applies to the lower first and lower second magnet rows. Therefore, a large and robust frame and a precise drive mechanism are required, which contributes to increased costs.

[0009] This invention was made in view of the above circumstances, and its objective is to provide an undulator that simplifies the drive mechanism for driving the magnet array compared to conventional methods, and enables switching between horizontal and vertical linear polarization.

[0010] To solve the above problems, the horizontal-vertical polarization undulator [1] according to the present invention comprises: an upper first magnet row in which a large number of magnets are arranged in a row; an upper second magnet row adjacent to the upper first magnet row in which a large number of magnets are arranged in a row; a lower first magnet row in which a large number of magnets are arranged in a row; and a lower second magnet row adjacent to the lower first magnet row in which a large number of magnets are arranged in a row, wherein the upper first magnet row and the upper second magnet row are arranged opposite to the lower first magnet row and the lower second magnet row with respect to a gap through which the electron beam moves, and is characterized by comprising a drive mechanism that moves the upper first magnet row and the upper second magnet row and the lower first magnet row and the lower second magnet row relative to each other in a horizontal direction perpendicular to the direction of propagation of the electron beam.

[0011] This configuration includes a drive mechanism that moves the upper first and upper second magnet rows and the lower first and lower second magnet rows relative to each other in a horizontal direction perpendicular to the direction of electron beam propagation. Therefore, it is possible to provide a horizontal and vertical polarization undulator that can reduce the influence of magnetic force when driving the magnet rows compared to conventional designs.

[0012] "Moving them relatively" includes cases where both the upper first magnet row and the upper second magnet row, and the lower first magnet row and the lower second magnet row are moved, as well as cases where only one of them is moved.

[0013] In the horizontal and vertical polarization undulator [2] according to the present invention, it is preferable that the drive mechanism in the horizontal and vertical polarization undulator [1] is capable of moving the upper first magnet row and the upper second magnet row and the lower first magnet row and the lower second magnet row in opposite directions to each other.

[0014] The horizontal / vertical polarization undulator [3] according to the present invention is a horizontal / vertical polarization undulator [1] or [2] in which the upper first magnet row and the upper second magnet row, and the lower first magnet row and the lower second magnet row are installed in a vacuum chamber, and comprises an upper magnet row support that supports the upper first magnet row and the upper second magnet row, a lower magnet row support that supports the lower first magnet row and the lower second magnet row, the drive mechanism installed outside the vacuum chamber, an upper connecting part that connects the upper magnet row support and the drive mechanism, and a lower connecting part that connects the lower magnet row support and the drive mechanism, wherein the upper connecting part and the lower connecting part are connected to the drive mechanism via a bellows mechanism provided in the vacuum chamber, and it is preferable that the bellows function allows relative movement by the drive mechanism while maintaining the vacuum state inside the vacuum chamber.

[0015] In the horizontal / vertical polarization undulator [4] according to the present invention, it is preferable that any of the horizontal / vertical polarization undulators [1] to [3] is provided with a gap driving mechanism for changing the size of the gap.

[0016] Figure 2 shows a diagram illustrating the configuration of a conventional undulator. Figure 3 shows a diagram illustrating the configuration of a conventional undulator. Figure 4 shows a diagram illustrating the configuration of a conventional undulator. Figure 5 shows a schematic cross-section of the undulator according to this embodiment, cut in a direction perpendicular to the direction in which the electron beam moves. Figure 6 shows a cross-sectional diagram showing the bellows mechanism used in the undulator of Figure 2. Figure 7 shows the initial magnet arrangement. Figure 8 shows the magnetic field state. Figure 9 shows the state in which the upper magnet row is driven to the right and the lower magnet row is driven to the left from the state in Figure 4A. Figure 5 shows the magnetic field state in the state in Figure 5A. Figure 7 shows a schematic diagram illustrating the configuration of the magnet row according to this embodiment. Figure 8 shows a schematic diagram showing the state in which the magnet row has been moved. Figure 8 shows the initial magnet arrangement according to another embodiment. Figure 9 shows the magnetic field state in the state in Figure 8A. Figure 9 shows the state in which the upper magnet row is driven to the right and the lower magnet row is driven to the left from the state in Figure 8A.

[0017] A preferred embodiment of the horizontal and vertical polarization undulator according to the present invention will be described with reference to the drawings. Figure 2 is a cross-sectional view of the undulator according to this embodiment, cut in a direction perpendicular to the direction in which the electron beam moves. Figure 3 is a diagram showing the bellows mechanism used in the undulator of Figure 2.

[0018] Figure 6 is a schematic diagram showing the configuration of the magnet array according to this embodiment. Components other than the magnet array are omitted from the illustration.

[0019] <Configuration of Magnet Rows> The horizontal and vertical polarization undulator comprises an upper first magnet row 1 in which a large number of magnets are arranged in a row, an upper second magnet row 2 adjacent to the upper first magnet row 1 in which a large number of magnets are arranged in a row, a lower first magnet row 3 in which a large number of magnets are arranged in a row, and a lower second magnet row 4 adjacent to the lower first magnet row 3 in which a large number of magnets are arranged in a row. As also shown in Figure 4A, the upper first magnet row 1 and the upper second magnet row 2 are positioned opposite the lower first magnet row 3 and the lower second magnet row 4, separated by a gap G through which the electron beam moves.

[0020] Figures 4A and 6 show the initial positions of the magnet arrays before they are moved. For ease of explanation, the x, y, and z coordinate axes are shown. The x-axis is the horizontal direction perpendicular to the direction of electron beam propagation. The y-axis is the direction of electron beam propagation and the longitudinal direction of the magnet arrays. The z-axis is the height direction of the undulator. The upper first magnet array 1 and the lower first magnet array 3 are directly opposite each other, and the upper second magnet array 2 and the lower second magnet array 4 are directly opposite each other.

[0021] The upper first magnet row 1 and the upper second magnet row 2 are adjacent to each other horizontally (in the y-axis direction), but there may or may not be a gap of an appropriate size between the upper first magnet row 1 and the upper second magnet row 2. If a gap is provided, some other member may be interposed, or it may simply be an empty space. The same applies to the lower first magnet row and the lower second magnet row. For the sake of explanation, the upper first magnet row 1 and the upper second magnet row 2 together may be referred to as the upper magnet row group, and the lower first magnet row and the lower second magnet row together may be referred to as the lower magnet row group.

[0022] Figure 6 shows the magnetization direction of each magnet constituting the magnet array with arrows. Inside the magnet, the magnetization direction is from the south pole to the north pole. The upper second magnet array 2 consists of the first magnet 20, second magnet 21, third magnet 22, fourth magnet 23, and so on, arranged from front to back. All magnets are the same size and width. A number of magnets are arranged along the array direction, with four magnets forming one set. The length of the four magnets in the y-direction is shown as f, and can be called the array period.

[0023] The magnetization direction of magnet 40, which constitutes the lower second magnet row, is horizontal and aligns with the y-axis from front to back. The magnetization direction of magnet 41 is vertical and aligns with the z-axis from bottom to top. The magnetization direction of magnet 42 is horizontal and aligns with the y-axis from back to front. The magnetization direction of magnet 43 is vertical and aligns with the z-axis from top to bottom.

[0024] The magnetization direction of magnet 20, which constitutes the upper second magnet row, is horizontal and aligns with the y-axis from back to front. The magnetization direction of magnet 21 is vertical and aligns with the z-axis from top to bottom. The magnetization direction of magnet 22 is horizontal and aligns with the y-axis from front to back. The magnetization direction of magnet 23 is vertical and aligns with the z-axis from bottom to top.

[0025] In the state shown in Figure 6, magnets 21 and 41 are positioned so that their magnetic field lines repel each other. Magnets 23 and 43 are also positioned so that their magnetic field lines repel each other.

[0026] Although not shown in the diagram, the magnet arrangement of the upper first magnet row 1 is the same as that of the lower second magnet row 4. Similarly, the magnet arrangement of the lower first magnet row 3 is the same as that of the upper second magnet row 2. In other words, the magnet rows arranged diagonally in a front view have the same arrangement structure.

[0027] <Undulator Configuration> Figure 2 shows a cross-sectional view of the undulator according to this embodiment, cut in a direction perpendicular to the direction in which the electron beam moves.

[0028] Each of the magnet arrays 1, 2, 3, and 4 is sealed inside the vacuum chamber 5, and the inside is maintained in a vacuum state. The mechanism (not shown) for creating a vacuum inside the vacuum chamber 5 can be carried out using a known vacuum pump or the like.

[0029] The upper first magnet row 1 and the upper second magnet row 2 are fixed to the upper magnet support frame 600. The upper magnet support frame 600 is connected to the upper drive mechanism 80 via a connecting shaft 60, two rows of connecting shafts 61, a hollow shaft 70, a bellows mechanism 71, etc. These connecting shafts 60, two rows of connecting shafts 61, a hollow shaft 70, a bellows mechanism 71, etc., correspond to the upper connecting section.

[0030] The connecting shaft 60 is equipped with a lower flange 601 and an upper flange 602, with the lower flange 601 connected to the upper magnet support frame 600. The upper flange is connected to the lower part of the connecting shaft 61. The connecting shaft 61 protrudes to the outside of the vacuum chamber 5 through a hole formed in the vacuum chamber 5 and is connected to the upper drive mechanism 80. The hole formed in the vacuum chamber 5 is set to be larger than the outer diameter of the connecting shaft 60, allowing the connecting shaft 60 to move within a predetermined range. Even with this configuration, the vacuum inside the vacuum chamber 5 is maintained by the bellows mechanism described later.

[0031] Figure 3 shows the configuration of the bellows mechanism 71. The bellows mechanism 71 is located outside the vacuum chamber. The bellows mechanism 71 shown is an example, but the mechanism disclosed in Japanese Patent Application Publication No. 2019-175766 can be used. The connecting shaft 61 comprises a small-diameter tip shaft 611, a main shaft 612, and a large-diameter flange 610. The tip shaft 611 connects to the upper flange 602 of the connecting shaft 60. The flange 610 connects to the upper drive mechanism 80. The specific connecting mechanism is not shown, but it can be constructed using well-known mechanical elements such as guide rails and gear mechanisms, as disclosed in the above-mentioned prior art.

[0032] In Figure 2, the upper first magnet row 1 and the upper second magnet row 2 are supported and fixed by a single upper magnet support frame 600, but the present invention is not limited thereto. For example, magnet support frames may be provided for each of the upper first magnet row 1 and the upper second magnet row 2, and these magnet support frames may be joined together. Furthermore, the number of components constituting the upper magnet support frame 600 is not particularly limited. In addition, a material suitable for supporting magnets (for example, a magnetic material) can be appropriately selected.

[0033] The components constituting the upper connecting section are also merely an example shown in Figure 2 and can be modified as appropriate. For example, the shape and number of connecting shafts can be changed as needed. Furthermore, mechanical elements other than shafts may also be used.

[0034] The lower first magnet row 3 and the lower second magnet row 4 are fixed to the lower magnet support frame and connected to the lower drive mechanism 90 via the lower connecting section. The specific configuration is the same as that of the upper magnet support frame 600 and the upper connecting section, so the explanation is omitted. The same applies to the modified configuration.

[0035] The upper drive mechanism 80 and the lower drive mechanism 90 correspond to drive mechanisms that relatively move the upper first magnet row 1 and the upper second magnet row 2, and the lower first magnet row 3 and the lower second magnet row 4 in a direction perpendicular to the direction of electron beam propagation (x-direction). Here, the upper magnet row group is driven to move as a whole, and the lower magnet row group is also driven to move as a whole. The specific configuration of the drive mechanism consists of a drive source such as a motor, a gear train that transmits the rotation of the motor, and mechanical elements such as a guide mechanism.

[0036] In the schematic diagram of Figure 2, the upper drive mechanism 80 and the lower drive mechanism 90 are represented as separate, independent drive mechanisms, but the configuration is not limited to this. For example, a single drive source can be used, and the mechanical elements can be branched from it to transmit power to the upper and lower connecting parts. Of course, each can function as an independent drive mechanism, and each can have its own drive source.

[0037] Figure 4A shows the initial magnet arrangement, and Figure 4B shows the polarization state at that time. The center of the electron beam E in the direction of propagation is indicated by a black circle in Figure 4A. The center of the electron beam E is exactly halfway between the upper first magnet row 1 and the upper second magnet row 2, and also exactly halfway between the lower first magnet row 3 and the lower second magnet row 4. In reality, the electron beam E propagates in a meandering manner, so this indicates the center in the direction of its propagation.

[0038] A gap is formed between the upper and lower magnet array groups for the electron beam to pass through. The size (distance) of the gap can be set as appropriate, but it can be determined according to the required wavelength, etc.

[0039] Figure 4A shows magnets 23 and 43 facing each other. In this state, the magnetic field lines repel each other. Similarly, for the magnets 13 of the upper first magnet row 1 and 33 of the lower first magnet row 3, although their magnetization directions are opposite, the magnetic field lines also repel each other. Therefore, as shown in Figure 4B, a horizontal magnetic field is formed in the gap, and the polarization direction of the synchrotron radiation is perpendicular.

[0040] Figure 5A shows the state after the upper magnet array group is driven to the right and the lower magnet array group is driven to the left, starting from the state in Figure 4A. The amount of movement to the right and the amount of movement to the left are the same and are driven by the upper drive mechanism 80 and the lower drive mechanism 90, respectively.

[0041] Figure 5B shows the magnetic field state when the magnet array is moved, and it is nearly perpendicular. The amount of movement is ±10 mm, which is a relative movement of 20 mm. The reason it is not a perfectly perpendicular magnetic field is due to the influence of adjacent magnets, but by increasing the size of the magnets for synchrotron radiation applications, it is possible to approach a more perfectly perpendicular magnetic field. In the state shown in Figure 5B, the synchrotron radiation is horizontally polarized.

[0042] In this embodiment, the upper drive mechanism 80 and the lower drive mechanism 90 drive each magnet array in synchronous motion. The upper magnet array group and the lower magnet array group are driven in opposite directions to prevent the center position of the electron beam E from changing. The amount of movement in each direction is also the same, and the upper drive mechanism 80 and the lower drive mechanism 90 are controlled by a control unit (not shown) to achieve this movement.

[0043] In the aforementioned prior art Apple-II type undulator, it is necessary to move the adjacent upper first magnet row 101 and upper second magnet row 102 relatively, and the adjacent lower first magnet row 201 and lower second magnet row 202 relatively, in order to change the polarization state. A large magnetic force acts to move the adjacent magnet rows side by side relatively. In addition, the direction and strength of the magnetic force acting changes when the magnet rows are moved. Specifically, attractive and repulsive forces act alternately between the magnet rows. Therefore, a large and robust frame and a precise drive mechanism are required.

[0044] On the other hand, in the present invention, the magnet arrays adjacent side by side do not move relative to each other. The upper first magnet array 1 and the upper second magnet array 2 (upper magnet array group) move integrally, and the lower first magnet array 3 and the lower second magnet array 4 (lower magnet array group) also move integrally. Further, since the upper magnet array group and the lower magnet array group move relative to each other with a gap therebetween, the acting force is smaller than that of a conventional undulator.

[0045] In addition to the above advantages, in the case of the present invention, not only the movement area of the electron beam but also the magnet arrays are sealed in a vacuum chamber in a form that can maintain an ultra-high vacuum state (for example, a vacuum degree of 10 ―７ or less). In the case of an APPLE-II type undulator, since the magnet arrays adjacent side by side move relative to each other, it is necessary to provide a mechanical sliding portion and a lubrication mechanism for smooth movement inside the vacuum chamber. Therefore, it is difficult to realize a vacuum-sealed APPLE-II type undulator that satisfies a sufficient ultra-high vacuum degree required in an accelerator.

[0046] On the other hand, in the case of the present invention, since the movement between the magnet arrays is a movement through a gap, a lubrication mechanism inside the vacuum chamber as in the prior art is not required. Since the present invention is driven through a bellows mechanism 71, the mechanically sliding portion exists outside the vacuum chamber 5. Therefore, the present invention has the advantage that an ultra-high vacuum can be realized.

[0047] In the present embodiment, a configuration in which the upper magnet array group and the lower magnet array group are moved in opposite directions to each other is adopted, but the present invention is not limited to this. For example, only the upper magnet array group may be moved, or only the lower magnet array group may be moved. However, when only one of the upper and lower magnet array groups is moved, the movement center of the electron beam changes, so a mechanism for correcting this is separately required.

[0048] The undulator according to the present invention is useful for future semiconductor photolithography applications. In semiconductor exposure, the use of free electron lasers (FELs) has been proposed to increase the intensity of EUV light with a wavelength of 13.5 nm. Currently, EUV light from mainstream LPP light sources is unpolarized, while EUV-FEL light is linearly polarized. Switching between horizontal and vertical polarization is considered necessary for efficient lithography, and a variable polarization undulator like the one of the present invention is particularly useful.

[0049] As mentioned above, the APPLE-II type undulator can switch between horizontal and vertical polarization. However, when the magnet array is sealed in a vacuum chamber, the sliding surfaces between adjacent magnet arrays are located inside the vacuum chamber, making it unsuitable for use when ultra-high vacuum is required. In this respect, the variable polarization undulator according to the present invention is superior to the APPLE-II type undulator.

[0050] Furthermore, the horizontal and vertical polarization undulators according to the present invention can be made relatively smaller than conventional Apple-II type undulators, contributing to cost reduction. To achieve miniaturization, it is conceivable to shorten the arrangement period of the magnet array (shown as f in Figure 6). However, simply shortening the period length will weaken the magnetic field. Therefore, in order to shorten the period length while maintaining the strength of the magnetic field, it is necessary to reduce the gap.

[0051] In the case of an undulator where only the electron beam passage area is sealed with a vacuum chamber, the vacuum chamber obstructs the gap, making it impossible to narrow it. On the other hand, the variable polarization undulator of the present invention can be vacuum-sealed including the magnet array, so the gap can be set to be smaller. Therefore, when achieving the same magnetic field strength, the period length of the magnet array can be shortened in the case of the present invention, which contributes to miniaturization.

[0052] <Gap Driving Mechanism> Figure 2 shows the upper gap driving mechanism 81 and the lower gap driving mechanism 91. By driving these, the size of the gap can be changed. By changing the gap, the magnitude of the magnetic force can be changed. Regarding the specific configuration of the gap driving mechanism, the mechanism disclosed in the aforementioned Patent Document 2 can be used. Note that the gap driving mechanism is not an essential component and does not need to be provided. Even when changing the gap, since the bellows mechanism 71 is provided, the gap can be changed while maintaining the vacuum level of the vacuum chamber 5.

[0053] <Switching between circular and linear polarization> Although there are currently no applications for this using synchrotron radiation, this undulator can also switch between circular and linear polarization. Figures 8 and 9 illustrate an embodiment of switching from circular to linear polarization.

[0054] Figure 8A shows the initial state of the magnet array. The magnets 13 of the upper first magnet array 1 and 23 of the upper second magnet array 2 have opposite and perpendicular magnetization directions. On the other hand, the magnets 32 of the lower first magnet array 3 and 42 of the lower second magnet array 4 have opposite and horizontal magnetization directions. The symbols of the magnets are as shown in Figure 6, and the initial position is phase-shifted horizontally (y-direction) from the magnet array shown in Figure 6. In this state, as shown in Figure 8B, the electron beam passes through in a circularly polarized state.

[0055] Figure 9A shows the state where the upper and lower magnet array groups are moved in opposite directions, similar to the case in Figure 5B. Figure 9B shows the magnetic field after the movement, which switches from circularly polarized to nearly perpendicular. The reason it is not a perfectly perpendicular magnetic field is due to the influence of adjacent magnets, as mentioned above. In this state, the electron beam becomes horizontally polarized.

[0056] <Another Embodiment> In this embodiment, the entire magnet array is installed inside the vacuum chamber, but it is also possible to configure the system so that only the space in which the electron beam moves is used as the vacuum chamber, and the magnet array is placed outside the vacuum chamber. Even when the magnet array is placed outside the vacuum chamber, the drive mechanism can be configured in the same way as in this embodiment. Modifications of this embodiment can also be applied to undulators in which the magnet array is placed outside the vacuum chamber.

[0057] In this embodiment, horizontal and vertical polarization have been described. However, in the present invention, horizontal polarization does not only represent a perfectly horizontal state, but also includes a state in which a slight inclination from horizontal is present due to the weak inclusion of a vertical polarization component from adjacent magnet rows. This can be achieved by changing the magnet size according to the application.

[0058] E Electron beam 1 Upper first magnet row 2 Upper second magnet row 3 Lower first magnet row 4 Lower second magnet row 5 Vacuum chamber 60 Connecting shaft 600 Upper magnet support frame 71 Bellows mechanism 80 Upper drive mechanism 81 Upper gap drive mechanism 90 Lower drive mechanism 91 Lower gap drive mechanism

Claims

1. A horizontal-vertical polarization undulator comprising: an upper first magnet row in which a large number of magnets are arranged in a row; an upper second magnet row adjacent to the upper first magnet row in which a large number of magnets are arranged in a row; a lower first magnet row in which a large number of magnets are arranged in a row; and a lower second magnet row adjacent to the lower first magnet row in which a large number of magnets are arranged in a row, wherein the upper first magnet row and the upper second magnet row are arranged opposite to the lower first magnet row and the lower second magnet row via a gap through which the electron beam moves, and the horizontal-vertical polarization undulator is characterized by comprising a drive mechanism for relatively moving the upper first magnet row and the upper second magnet row and the lower first magnet row and the lower second magnet row in a horizontal direction perpendicular to the direction of propagation of the electron beam.

2. The horizontal and vertical polarization undulator according to claim 1, wherein the drive mechanism is capable of moving the upper first magnet row and the upper second magnet row and the lower first magnet row and the lower second magnet row in opposite directions to each other.

3. The horizontal and vertical polarization undulator according to claim 1 or 2, wherein the upper first magnet row and upper second magnet row, and the lower first magnet row and lower second magnet row are installed in a vacuum chamber, and the undulator comprises an upper magnet row support that supports the upper first magnet row and upper second magnet row, a lower magnet row support that supports the lower first magnet row and lower second magnet row, the drive mechanism installed outside the vacuum chamber, an upper connecting portion that connects the upper magnet row support and the drive mechanism, and a lower connecting portion that connects the lower magnet row support and the drive mechanism, wherein the upper connecting portion and the lower connecting portion are connected to the drive mechanism via a bellows mechanism provided in the vacuum chamber, and the bellows function enables relative movement by the drive mechanism while maintaining the vacuum state inside the vacuum chamber.

4. The horizontal / vertical polarization undulator according to claim 1, further comprising a gap driving mechanism for changing the size of the gap.

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