JPH09161999A - Undulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a device and move permanent magnet groups as near as possible to an electron beam by providing a drive mechanism moving a pair of magnet holders in the direction for increasing or decreasing the gap between a pair of permanent magnet groups. SOLUTION: A drive motor and a drive shaft constitute a drive mechanism moving an array of permanent magnet groups 2, 3 via magnet holders 4a, 4b, increasing or decreasing the gap between the permanent magnet groups 2, 3, and moving the permanent magnet groups 2, 3 near to or apart from an electron beam. The array gap between the permanent magnet groups 2, 3 can be optionally changed, the permanent magnet groups 2, 3 are moved as near as possible to the electron beam, and the magnetic force can be effectively applied to the electron beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undulator installed in a charged particle accelerator using synchrotron radiation, and more particularly to an undulator having a structure in which a plurality of permanent magnets are arranged along an electron beam orbit.

[0002]

2. Description of the Related Art It is known that high-energy electrons emit various electromagnetic waves when they make circular motions or vibrations, and one of the radiations is synchrotron radiation. This synchrotron radiation is accelerated to a high energy state of several hundred million electron volts (several hundred MeV) or more and propagates in vacuum at almost the speed of light. This is a phenomenon in which light called radiated light is emitted in a certain direction. This synchrotron radiation is generally
In the circular accelerator, the deflection magnetic field of the deflection electromagnet is implemented by accelerating an accelerating electron beam in a direction perpendicular to the electron orbit.

The emitted light by this synchrotron radiation is continuous light having a wavelength of several angstroms to several thousand angstroms, and the integrated radiant power is extremely large.
However, light having a wavelength other than the wavelength used damages the object to be irradiated, and thus there is a demand to use the light in a narrow wavelength range by dispersing it. In order to meet this demand, if the wavelength is shortened, the intensity of the radiated light will decrease, and the light source will not have high brightness. Therefore, in order to satisfy the demands for shortening the wavelength and increasing the brightness, undulator radiation by an undulator (electronic meandering device), which is one of insertion-type light sources, has been studied and used.

FIG. 14 shows, for example, JP-A-4-3243.
00 is a side view of a conventional undulator described in JP-A-4-271000. When the electron beam direction is the Z-axis direction, on both sides in the Y-axis direction of the passage of the electron beam,
The permanent magnet groups 2 and 3 are arranged adjacent to each other and facing each other. The permanent magnet groups 2 and 3 are arranged such that the directions of the adjacent magnets (in the figure, the directions of the arrows indicate the directions of the magnetization) are adjacent to each other, and the magnetic fields are arranged in a periodical magnetic field in the Z-axis direction. generate.

The electron beam entering the thus formed periodic magnetic field from the Z-axis direction in FIG. 14 receives the Lorentz force from the periodic magnetic field in the X-axis direction and meanders while drawing a trajectory similar to the periodic magnetic field distribution.

For example, if this periodic magnetic field B _y is B _y = B ₀ sin (2πz / λ) ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (1), with respect to the Z axis of the electron orbit. Maximum slopes Ψ ₀ and γ
The ratio K of ^-1, de magnetic field strength B ₀ and (tesla) cycle length lambda and _{(cm) K = Ψ 0 /} γ -1 = 0.934B 0 ( tesla) λ (cm) ‥‥‥‥‥‥ It is expressed as (2). However, when the electron energy is E (GeV), γ = 1957 · E ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (3). Also, the fundamental wavelength λ ₁ of this synchrotron radiation
_{Is, λ 1 = λ (1 +} K 2/2) / 2γ 2 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (4) next, K increases, that is, as a strong long magnetic field period length, also It can be seen that the lower the electron beam energy, the longer the fundamental wavelength λ ₁ .

On the other hand, the intensity of the emitted light increases as the number of cycles N increases,
It is amplified up to N ² times from N times due to coherence. Furthermore, the harmonic characteristic strongly depends on this K value, and when K << 1, the spectrum is only the fundamental wave. On the other hand, K >> 1
In the case of, it becomes a series of harmonics much like synchrotron radiation in a circular orbit, and becomes broadband continuous spectrum light. Radiation with K <3 is called undulator radiation, and radiation with K> 3 is called wiggler radiation. In particular, the undulator radiation has a brightness 10 ³ to 10 ⁴ times higher than that of the synchrotron radiation in a circular orbit, becomes tunable quasi-monochromatic light, and becomes linearly polarized light having an electric vector parallel to the meandering surface of the electron beam. This characteristic is of extremely high practical value.

To select and use various wavelengths λ ₁
As can be seen from (4), electron beam energy or K
You need to control the value. However, the electron beam energy-E value of the electron storage ring to which the undulator is attached is usually fixed for a long period of time,
Generally, by changing the distance G between the permanent magnet groups 2 and 3, the strength of the magnetic field exerted by the permanent magnet groups 2 and 3 on the electron beam is changed, and the K value is changed to change the wavelength λ ₁ A selection is being made.

In FIG. 14, the permanent magnet group 2 is fixed to the magnet holder 4a and arranged on the upper base 5. The permanent magnet group 3 is fixed to the magnet holder 4b and arranged on the lower base 5. The permanent magnet groups 2 and 3 are arranged such that the directions of adjacent ones (in the figure, the directions of the arrows indicate the directions of magnetization) are shifted by 90 degrees. The magnet holders 4a and 4b are made of a non-magnetic material such as aluminum alloy.

A vacuum duct 1 supported by an external fixed portion is sandwiched between a permanent magnet group 2 and a permanent magnet group 3 arranged vertically. The vacuum duct 1 is a cylindrical container made of a non-magnetic material, the inside of which is evacuated, and the electron beam passes through.

FIG. 15 shows, for example, JP-A-4-3243.
FIG. 10 is a perspective view of a conventional undulator described in Japanese Patent Laid-Open No. 00 and Japanese Patent Laid-Open No. 4-271000. Upper base 5
The lower base 6 is attached to the supporting frames 7 and 8 via a rail (not shown), and can slide up and down. A drive motor 9 is provided at the upper and lower ends of the support bases 7 and 8, and the bases 5 and 6 are slid vertically via a drive shaft. The respective arrays of the permanent magnet group 2 and the permanent magnet group 3 arranged vertically are spaced apart from each other and approached vertically with the vacuum duct 1 as the center.

In the conventional undulator thus constructed, the permanent magnet groups 2 and 3 are arranged such that the directions of the adjacent magnet groups are shifted by 90 degrees from each other.
Generates a periodic magnetic field in the axial direction. The bases 5 and 6 are supported by support frames 7 and 8 via rails (not shown), and have a structure capable of sliding up and down. In the arrangement of the permanent magnet group 2 and the permanent magnet group 3 arranged vertically, the gap G between the two can be arbitrarily changed centering on the vacuum duct 1. As a result, the strength of the magnetic field exerted on the electron beam is changed, that is, the K value in equation (4) is changed, and electron beams having different wavelengths λ ₁ can be obtained.

[0013]

Since the conventional undulator is constructed as described above, the wavelength of the electron beam is selected by changing the K value, that is, the distance G between the permanent magnet groups 2 and 3. It was done by changing. That is, when the permanent magnet groups 2 and 3 are brought close to the electron beam, a large magnetic field can be applied to the electron beam, and the wavelength λ _{1 of the} fundamental wave can be lengthened. Further, if the permanent magnet groups 2 and 3 are moved away from the electron beam, the magnetic field exerted on the electron beam becomes small, and the wavelength λ _{1 of the} fundamental wave can be shortened.

However, since the conventional undulator is constructed as described above, the permanent magnet groups 2 and 3 cannot be brought close to the electron beam due to the existence of the vacuum duct 1. Therefore, the magnetic force of the permanent magnet groups 2 and 3 could not be effectively utilized.

As a method for solving such a problem, there has been a method in which the entire apparatus is put in a large vacuum apparatus. However, this method has a problem that the device becomes larger and more complicated.

The present invention has been made in order to solve the above-mentioned problems, and can downsize the device,
An object is to obtain an undulator that can make a permanent magnet as close as possible to an electron beam, can effectively utilize the magnetic force of the permanent magnet, and can change the wavelength of the electron beam.

[0017]

In the undulator of claim 1, an electron beam inlet is provided at one end and an electron beam outlet is provided at the other end, and an undulator is introduced from the electron beam inlet. In a state in which the array direction is shifted along the passage so that a periodic magnetic field is formed in the passage of the electron beam derived from the electron beam outlet, and
A pair of permanent magnets arranged in parallel in the vacuum duct so as to face each other across the passage, a pair of magnet holders provided in the vacuum duct for respectively holding the pair of permanent magnets, and a pair of magnet holders. And a drive mechanism for moving each of them in a direction of increasing or decreasing the gap between the pair of permanent magnet groups.

According to another aspect of the undulator of the present invention, the vacuum duct is provided with an electron beam inlet and an electron beam outlet at both ends, and has a frame shape having a pair of opposite sides orthogonal to the passage of the electron beam as openings. Duct main body, a pair of base flanges that close the opening of the duct main body, and a pair of bellows that airtightly connect the pair of base flanges to the duct main body. And is configured to be moved by a drive mechanism via a pair of base flanges.

According to another aspect of the undulator of the present invention, the vacuum duct is provided with an electron beam inlet and an electron beam outlet at both ends, and an opening is provided in each of a pair of base flanges facing each other orthogonal to the passage of the electron beam. A duct main body, a flange that closes the opening, and a bellows that airtightly connects the flange to the pair of base flanges. It is attached to the drive rod that extends in the direction orthogonal to
It is configured to be moved by a drive mechanism via a drive rod.

According to another aspect of the undulator of the present invention, a vacuum duct having an electron beam inlet at one end and an electron beam outlet at the other end, and an electron beam inlet leading out from the electron beam outlet. Are arranged in parallel with each other so as to form a periodic magnetic field in the passage of the electron beam, with the arrangement direction shifted along the passage and facing each other across the passage. Arranged with different gaps so as to form a magnetic field orthogonal to the passage in the same period as the pair of permanent magnets and a permanent magnet that forms a magnetic field orthogonal to the passage in the pair of permanent magnets. And a plurality of pairs of magnetic pole pieces arranged side by side in a direction perpendicular to the magnetic field and the passage in the vacuum duct, and the vacuum duct in a direction perpendicular to the magnetic field and the passage. And a drive mechanism for.

In the undulator of the fifth aspect, a magnetic pole gap positioning plate that defines a gap between opposing inner wall surfaces of the vacuum duct in a magnetic field direction orthogonal to the passage is provided between adjacent pairs of a plurality of pairs of magnetic pole pieces. It is arranged.

According to another aspect of the undulator of the present invention, a vacuum duct having an electron beam inlet at one end and an electron beam outlet at the other end, and an electron beam inlet and an electron beam outlet. Are arranged in parallel with each other so as to form a periodic magnetic field in the passage of the electron beam, with the arrangement direction shifted along the passage and facing each other across the passage. A pair of permanent magnets and a pair of permanent magnets arranged opposite to each other to form a magnetic field orthogonal to the passage in the same cycle as the permanent magnet that forms a magnetic field orthogonal to the passage in the pair of permanent magnets. The magnetic pole piece group includes a magnetic pole piece group cartridge that is arranged between a pair of support bases that are arranged opposite to each other, and that is attached to the vacuum duct so as to be insertable into the vacuum duct.

In the undulator according to claim 7, the vacuum duct has a plurality of pairs of magnetic pole piece group cartridges having gaps between different magnetic pole piece groups inside the vacuum duct, the magnetic field being orthogonal to the passage and the passage being orthogonal to the passage. Are arranged in parallel with each other, and are configured so as to be movable in a magnetic field orthogonal to the passage and a direction orthogonal to the passage.

In the undulator of the eighth aspect, a vacuum duct having an electron beam inlet at one end and an electron beam outlet at the other end, and an electron beam inlet and an electron beam outlet are introduced. In the vacuum duct, the electron beams are arranged in different directions along the passage so that a periodic magnetic field is formed in the passage, and they are opposed to each other across the passage and have different gaps. A magnetic field orthogonal to the passage of the periodic magnetic field and a plurality of pairs of permanent magnets arranged in parallel in the directions orthogonal to the passage, and a vacuum duct are moved in the directions orthogonal to the magnetic field and the passage orthogonal to the passage. And a drive mechanism.

In the undulator of the ninth aspect, each pair of permanent magnet groups forms a periodic magnetic field in the passage of the electron beam between the pair of support stands arranged in opposition to each other. With the array direction shifted along
In addition, the permanent magnet group cartridges are arranged so as to face each other with the passage therebetween.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a side view of an essential part showing an example of the undulator of the present invention with a partial cross section. FIG. 2 is a perspective view showing the entire undulator. The permanent magnet groups 2 and 3 are fixedly arranged on the upper base flange 10 and the lower base flange 11 via magnet holders 4a and 4b, respectively. The array of the permanent magnet group 2 and the array of the permanent magnet group 3 face each other. The permanent magnet group 2 and the permanent magnet group 3 are adjacent to each other in the same direction (in the figure, the direction of the arrow indicates the direction of magnetization) as in the conventional example.
They are arranged in a staggered manner. Opposing permanent magnet group 2
Between the and the permanent magnet group 3, there is a passage for the electron beam as in the conventional case.

Electron beam passage and each permanent magnet group 2
In addition, a rectangular frame-shaped duct main body 13 having openings on the upper and lower sides orthogonal to the passage of the electron beam is arranged so as to surround the tip ends of the arrangement of 3 and 3. The duct body 13 is provided with cylindrical portions 13a and 13b serving as electron beam inlets and outlets on two short sides at both ends.

An accordion type bellows 12 is attached to the upper peripheral edge of the duct main body 13 over the entire circumference and extends to the upper upper base flange 10. The accordion type bellows 12 includes a permanent magnet group 2 and a magnet holder 4a.
Is covered. An accordion type bellows 12 is similarly attached to the lower peripheral edge of the duct body 13 and extends to the lower base flange 11. The lower accordion bellows 12 covers the permanent magnet group 3 and the magnet holder 4b. Duct body 13, upper and lower two accordion type bellows 12, and a pair of base flanges 1
0 and 11 form an airtight space, and constitute a vacuum duct 50 that houses the array of the permanent magnet groups 2 and 3.

Cylindrical portions 13a and 13b of the duct body 13
Is connected to an external device (not shown). The inside of the vacuum duct 50 is evacuated. The electron beam is introduced from the tubular portion 13a, passes between the array of the permanent magnet groups 2 and the array of the permanent magnet groups 3 which face each other, and is led out through the tubular portion 13b.

The upper base flange 10 and the lower base flange 11 are fixed to the upper base 5 and the lower base 6, respectively. Although the duct body 13 is not shown,
It is directly fixed to the support base 7. As in the conventional case, the bases 5 and 6 are attached to the support frames 7 and 8 via rails, and can slide up and down. Support stand 7,8
A drive motor 9 is provided at the upper and lower ends as in the conventional case, and the bases 5 and 6 are slid up and down via a drive shaft. Then, the drive motor 9 and the drive shaft move the arrangement of the permanent magnet groups 2 and 3 via the magnet holders 4a and 4b to increase or decrease the gap between the permanent magnets 2 and 3 so that the permanent magnet groups 2 and 3 are moved. A driving mechanism 60 that moves the electron beam closer to or farther from the electron beam is configured.

In the undulator thus constructed, the permanent magnet groups 2 and 3 which are a pair of permanent magnet groups.
The gap distance G1 between the arrays can be arbitrarily changed, and there is no obstruction between the array of the permanent magnet groups 2 and 3 and the electron beam, and the permanent magnet groups 2 and 3 are as close to the electron beam as possible. Therefore, the magnetic force of the permanent magnet groups 2 and 3 can be effectively applied to the electron beam.

Therefore, in order to obtain an electron beam having the same wavelength, a magnet smaller than the conventional one can be used. As a result, the device can be made smaller than the conventional one. Further, the variable range of the K value can be widened, and the range of wavelengths selected can be widened. Further, the design is easy because it does not require a large design change as compared with the configuration of the conventional device.

Embodiment 2 FIG. FIG. 3 is a side view of a principal part showing a cross section of another example of the undulator of the present invention. FIG. 4 is a perspective view showing the entire undulator. The arrangement of the permanent magnet groups 2 and 3 is fixed to the upper base 5 and the lower base 6 via magnet holders 4a and 4b, respectively. The upper base 5 and the lower base 6 are each supported by a drive rod 14. The drive rod 14 is attached to the support pedestals 7 and 8 by a rail (not shown) and can slide up and down. A drive motor 9 is provided at the upper and lower ends of the support frames 7 and 8 as in the conventional case, and the bases 5 and 6 are slid up and down via a drive shaft. An electron beam passage is provided between the opposing permanent magnet group 2 and the permanent magnet group 3 as in the conventional case.

Electron beam passage and each permanent magnet group 2
In addition, a duct main body 17 of a rectangular box body is arranged so as to surround the tip end of the arrangement of 3 and the upper and lower sides orthogonal to the passage of the electron beam with the base flange 16. The duct body 17 is provided with cylindrical portions 17a and 17b serving as an electron beam inlet and outlet on two side surfaces at both ends.

A hole 16a, which is an opening, is formed in the upper and lower base flanges 16, and the drive rod 14 penetrates therethrough. An array of permanent magnet groups 2 and 3 supported by a drive rod 14 is located inside the duct body 17 so as to face each other.

A disc-shaped flange 14a is fixed to the intermediate portion of each drive rod 14. A drive bellows 15 is attached between the periphery of the hole 16a of each base flange 16 and the flange 14a of each drive rod 14. The duct body 17, the driving bellows 15 and the flange 14a constitute a vacuum duct 51 which is an airtight space for housing the permanent magnet groups 2 and 3, and the inside is evacuated. The tubular portions 17a and 17b are connected to an external device (not shown). The electron beam is introduced from the tubular portion 17a, passes between the array of the permanent magnet groups 2 and the array of the permanent magnet groups 3 facing each other, and is led out through the tubular portion 17b.

In the undulator thus constructed, the permanent magnet groups 2 and 3 which are a pair of permanent magnet groups.
The gap distance G1 between the arrays can be arbitrarily changed, and there is no obstruction between the array of the permanent magnet groups 2 and 3 and the electron beam, and the permanent magnet groups 2 and 3 are as close to the electron beam as possible. Therefore, the magnetic force of the permanent magnet groups 2 and 3 can be effectively applied to the electron beam.

Therefore, in order to obtain an electron beam of the same wavelength, a magnet smaller than the conventional one can be used. As a result, the device can be made smaller than the conventional one. Further, the variable range of the K value can be widened, and the range of wavelengths selected can be widened. Further, since the bellows 15 used is small, the structure is simplified.

Embodiment 3 FIG. 5 is a side view showing another example of the undulator of the present invention, showing the vicinity of the magnet portion.
FIG. 6 is a sectional view of a main part of the vacuum duct. FIG. 7 is a perspective view of a main part of the undulator.

In FIG. 5, the pair of vertically arranged permanent magnet groups 2 and 3 is attached to the bases 5 and 6 via the magnet holders 4a and 4b. An upper plate 20 and a lower plate 21 made of a non-magnetic material such as SUS are arranged between the vertically arranged permanent magnet groups 2 and 3 close to the permanent magnet groups 2 and 3. Inside the upper plate 20, magnetic pole pieces 18 a made of a magnetic material are arranged and fixed along the arrangement of the permanent magnet group 2. The array 18a of the magnetic pole pieces is arranged at a position of the permanent magnets arranged in the permanent magnet group 2 such that the magnetization direction thereof is the vertical direction, that is, one array is arranged for each array of the permanent magnet group 2. Further, on the inner side of the lower plate 21, the magnetic pole pieces 1 are similarly arranged along the arrangement of the permanent magnet group 3.
9a are arranged and fixed. Magnetic pole pieces 18a, 19
The array a is fixed by welding or flange joining.

The upper plate 20 and the lower plate 21 are sufficiently thin.
(For example, about 1 mm). Therefore, the magnetic resistance of the upper plate 20 and the lower plate 21 decreases, and the magnetic flux is transmitted from the permanent magnet group 2 to the magnetic pole piece 18a and from the permanent magnet group 3 to the magnetic pole piece 19a. Therefore, a periodic magnetic field is generated such that the gap distance between the permanent magnet groups 2 and 3 is reduced to the gap distance between the magnetic pole pieces 18a and 19a.

In FIG. 6, the upper plate 20 and the lower plate 21
Together with the two side plates 22 constitute a vacuum duct 40 which is a box. The upper plate 20 and the lower plate 30 are widened in the X-axis direction. Inside the upper plate 20, an array of magnetic pole pieces 18b and an array of magnetic pole pieces 18c are arranged in parallel with each other in parallel with the array of magnetic pole pieces 18a at a predetermined interval. That is, the three rows of magnetic pole pieces 18a, 18b, and 19c are arranged in parallel in the X-axis direction at predetermined intervals. Further, an array of magnetic pole pieces 19b and an array of magnetic pole pieces 19c are arranged in parallel on the inner side of the lower plate 21 at a predetermined interval in parallel with the array of magnetic pole pieces 19a.

Each pole piece 18a and 19a, 18b and 19
b, 18c and 19c are arranged facing each other. The gap distance A between the arrangement of the magnetic pole pieces 18a and the arrangement of the magnetic pole pieces 19a, the gap distance B between the arrangement of the magnetic pole pieces 18b and the arrangement of the magnetic pole pieces 19b, and the arrangement of the magnetic pole pieces 18c and the magnetic pole piece 1 are described.
The thickness of each pole piece is selected so that the gap distance C from the array of 9c changes stepwise.

In FIG. 7, the electron beam introduced through the opening at one end of the vacuum duct 40 passes through the passage in the center of the array of the pair of permanent magnet groups 2 and 3 in the vacuum duct 40. , Through the opening at the other end of the vacuum duct 40. End bellows 2 are provided at both ends of the vacuum duct 40.
3 is attached. The end bellows 23 is connected to an external device (not shown). A shaft 24a is erected on one side surface of the vacuum duct 40. A screw is threaded on the shaft 24a. An engaging member 24b is threadedly engaged with the shaft 24a. Further, a motor 24c for rotating the engagement member 24b to move the shaft 24a forward and backward is fixedly arranged outside. Shaft 24a, engaging member 2
4b and the motor 24c constitute a drive mechanism 24 for sliding the vacuum duct 40 in the X-axis direction.

In FIG. 7, the pole piece arrays 18b and 19b are shown.
Are adjacent to the permanent magnet group 2 and the permanent magnet group 3, respectively, but when the vacuum duct 40 slides to the right in FIG. 7 by the drive mechanism 24, the magnetic pole piece arrays 18a and 19a move to the permanent magnet group 2 and the permanent magnet group. Close to 3. At this time, the magnetic pole piece arrays 18a and 19a allow the magnetic flux to pass from the permanent magnet group 2 and the permanent magnet group 3. When the vacuum duct 40 slides to the left in FIG. 7, the magnetic pole piece arrays 18c and 19c move to the permanent magnet group 2
And approaches the permanent magnet group 3. In that case, the pole piece array 1
Magnetic flux is transmitted from the permanent magnet groups 2 and 3 to 8c and 19c.

In the undulator having such a structure, by sliding the vacuum duct 40 in the X-axis direction, the magnetic pole piece gap distance A to the position where the electron beam passes.
C can be selected, the K value can be made variable in a stepwise manner, and the wavelength of the electron beam can be changed.
Further, since the drive mechanism 24 only slides the vacuum duct 40, the drive mechanism is simpler than the conventional one.

Embodiment 4 FIG. 8 is a sectional view of a main part of a vacuum duct showing another example of the undulator of the present invention.
The present embodiment is similar to the third embodiment, but in the present embodiment, the upper plate 2 is provided inside the vacuum duct 40 between the opposing inner walls, that is, the upper plate 20 and the lower plate 21.
A magnetic pole gap positioning plate 25 that defines a gap between the zero plate and the lower plate 21 is provided. Magnetic pole gap positioning plate 25
Is a pair of pole piece arrays 18a and 19a, 18b
And 19b, and 18c and 19c are disposed adjacent to each other.

The inside of the vacuum duct 40 is the third embodiment.
In the same manner as the magnetic pole piece arrays 18a, 18b, 18c,
19a, 19b and 19c are arranged and fixed.
An attractive force is generated by the magnetic force between the pair of magnetic pole piece arrays through which the magnetic flux is transmitted by the permanent magnet group 2 and the permanent magnet group 3.
Since the inside of the vacuum duct 40 is evacuated, atmospheric pressure acts on the upper plate 20 and the lower plate 21. However, the upper plate 20 and the lower plate 21 of the vacuum duct 40 need to be made as thin as possible because the magnetic resistance must be reduced, and they are easily deformed. Therefore, the magnetic pole gap positioning plate 25, which is made of the same non-magnetic material such as SUS and is precisely processed in the height direction, is arranged near the magnetic pole piece array.

In the undulator having such a structure, the magnetic pole gap positioning plate 25 is the upper plate 2 of the vacuum duct 40.
Since 0 and the lower plate 21 are supported and positioned, it is possible to reduce variations in the pole piece gap distance caused by deformation of the vacuum duct 40. Further, it is possible to reduce the change of the magnetic field due to the variation of the magnetic pole piece gap distance, and there is an effect that the performance of the device is improved.

Embodiment 5. FIG. 9 is a perspective view of a main part showing another example of the undulator of the present invention. FIG. 10 is a sectional view of a main part. In the figure, an array of a pair of permanent magnet groups 2 and 3 arranged vertically is attached to bases 5 and 6 via magnet holders 4a and 4b. Between the vertically arranged permanent magnet groups 2 and 3, there is a cartridge housing which is an elongated box having an opening which is an electron beam inlet at one end and an opening which is an electron beam outlet at the other end. A vacuum duct 41 is arranged. A magnetic pole piece group cartridge 29 is inserted in the cartridge containing vacuum duct 41 which is an elongated box.

The magnetic pole piece group cartridge 29 includes an upper magnetic pole piece array 26 and a lower magnetic pole piece arranged above and below two cartridge supporting bases 28 made of a non-magnetic material such as SUS extending in the longitudinal direction of the vacuum accommodating duct 41. The array 27 and the array 27 are arranged and fixed.

Upper magnetic pole piece array 26 and lower magnetic pole piece array 27
Are arranged at the positions of the permanent magnets of the permanent magnet group 2 and the permanent magnet group 3 which are arranged so that the magnetization directions are vertical, that is, one is skipped with respect to the arrangement of the permanent magnet group 2 or the permanent magnet group 3. Are arranged in. The height of the cartridge support frame 28 is precisely manufactured and assembled so that the gap distance between the upper magnetic pole piece array 26 and the lower magnetic pole piece array 27 is accurate.

Upper magnetic pole piece array 26 and lower magnetic pole piece array 27
An attractive force is generated between and by the magnetic force. However, the suction force is received by the cartridge support frame 28 and does not reach the upper and lower plates of the cartridge accommodating vacuum duct 41.
Therefore, the upper plate and the lower plate can be made thinner.

The magnetic pole piece group cartridge 29 accommodated in the cartridge accommodating vacuum duct 41 includes the upper magnetic pole piece array 2
One cartridge selected from a large number of cartridges having different gap distances between 6 and the lower magnetic pole piece array 27 is set. After the appropriate cartridge is inserted into the cartridge accommodating vacuum duct 41, the inside is evacuated.

In the undulator having such a structure, the upper and lower plates of the vacuum duct 41, which need to be made as thin as possible, can be made thinner. Further, it is possible to reduce the change in the magnetic field due to the variation in the magnetic pole piece gap distance, and it is possible to obtain an undulator with stable performance. Further, since the magnetic pole piece array is not fixed inside the cartridge accommodating vacuum duct 41, and the magnetic pole piece group cartridge 29 is manufactured separately from the cartridge accommodating vacuum duct 41, the magnetic pole piece gap at the time of cartridge assembly is eliminated. The distance can be easily measured and adjusted, and the assemblability is improved.

As the magnetic pole piece group cartridge 29, one cartridge selected from a large number of cartridges having different gap distances between the upper magnetic pole piece array 26 and the lower magnetic pole piece array 27 is set. By changing the cartridge to be used, the gap distance between the upper magnetic pole piece array 26 and the lower magnetic pole piece array 27 can be changed, and the wavelength of the electron beam can be changed stepwise. Therefore, the drive mechanism is unnecessary in the present embodiment.

Embodiment 6 FIG. FIG. 11 is a diagram showing the structure of a vacuum duct for accommodating a plurality of cartridges showing another example of the undulator of the present invention. In the present embodiment, the width of the cartridge accommodating vacuum duct in the X-axis direction is widened so that a plurality of magnetic pole piece group cartridges according to the fifth embodiment can be accommodated. Vacuum duct for storing multiple cartridges 4
2 has a width increased in the X-axis direction and three magnetic pole piece group cartridges 29a to 29c are accommodated in parallel with each other with a predetermined gap.

Three magnetic pole piece group cartridges 29a to 29
2c, the magnetic pole piece array 2 is provided above and below the cartridge supporting bases 28a to 28c each made of a non-magnetic material such as SUS.
6a to 26c and 27a to 27c are arranged and fixed. At the time of assembling, the dimensions are measured to adjust the pole piece gap distance, and then the assembling is performed.

End bellows 31 are attached to both ends of the vacuum duct 42 for accommodating a plurality of cartridges. The end bellows 31 is connected to an external device (not shown). A drive mechanism 24 similar to that of the third embodiment is provided on one side surface of the vacuum duct 42 for accommodating a plurality of cartridges. Thereby, the vacuum duct 42 for accommodating a plurality of cartridges can slide in the X-axis direction.

Three magnetic pole piece group cartridges 29a to 29
In c, the gap distance A between the pole piece arrays 26a and 27a
1. The magnetic pole piece group cartridges 29a to 29c are selected and set so that the gap distance B1 between the magnetic pole piece arrays 26b and 27b and the gap distance C1 between the magnetic pole piece arrays 26c and 27c are changed stepwise.

In the undulator having such a structure, a plurality of magnetic pole piece group cartridges 29a to 29c having different intervals between the magnetic pole piece arrays are set, so that the plural cartridge containing vacuum duct 42 is moved in the X-axis direction. By sliding the magnetic pole piece gap distance A1 to C1 at the position where the electron beam passes, it is possible to select K
The value can be made variable, and the wavelength of the electron beam can be changed. Further, since a plurality of cartridges can be set in one set, workability is good.

Embodiment 7 FIG. 12 is a view showing the structure of a vacuum duct showing another example of the undulator of the present invention. Upper plate 20 and lower plate 21 made of a non-magnetic material such as SUS
Together with the two side plates 22 made of the same non-magnetic material constitute a vacuum duct 43 which is a box. Upper plate 2 of vacuum duct 43
0 and the lower plate 21 have permanent magnet groups 32a and 33a, respectively.
Are arranged and fixed by welding or flange joining. The permanent magnet groups 32a and 33a are arranged to face each other along the passage and across the passage of the electron beam so as to form a periodic magnetic field in the passage of the electron beam. On the upper plate 20 and the lower plate 21 of the vacuum duct 43, permanent magnet groups 32b, 32c, 33b, 33c are arranged in parallel with the permanent magnet groups 32a, 33a in the X-axis direction, and fixed in the same manner. .

Permanent magnet groups 32b and 33b, 32c and 33
c also face each other. At this time, the permanent magnet group 32
gap distance A2 of the arrangement of a and 33a, permanent magnet arrangement 32b
The thickness of the permanent magnets is selected so that the gap distance B2 of the arrangement of the magnets 33b and the gap distance C2 of the arrangement of the permanent magnets 32c and 33c changes stepwise.

On one side surface of the vacuum duct 43, a drive mechanism 24 similar to that of the third embodiment is installed. Further, end bellows (not shown) similar to those of the third embodiment are attached to both ends of the vacuum duct 43.

By sliding the vacuum duct 43 in the X-axis direction, the distance between the magnetic pole pieces at the position where the electron beam passes can be selected, and the K value can be made variable although it is stepwise.

Since the undulator having such a structure is provided with a plurality of pairs of permanent magnet arrays having different intervals, the electron beam passes by sliding the vacuum duct 43 in the X-axis direction. It is possible to select the permanent magnet gap distance A2 to C2 at the position
The value can be made variable, and the wavelength of the electron beam can be changed. Further, since there is no obstruction between the arrangement of the permanent magnets and the electron beam and the magnetic force of each permanent magnet can be effectively applied to the electron beam, the device can be downsized.

Embodiment 8 FIG. FIG. 13 is a sectional view of a vacuum duct for accommodating a plurality of cartridges showing another example of the undulator of the present invention. In the present embodiment, the width of the vacuum duct 44 for accommodating a plurality of cartridges is widened in the X-axis direction, and the three permanent magnet group cartridges 36 are provided therein.
a to 36c are stored in parallel with each other with a predetermined gap in the X-axis direction.

Three permanent magnet group cartridges 36a-3
6c, permanent magnet arrays 34a to 34c and 35a to 35c are arranged and fixed above and below the cartridge supporting bases 28a to 28c each made of a non-magnetic material such as SUS. At the time of assembling, dimensional measurement is performed to adjust the magnetic pole piece gap distance, and the assembling is performed accurately.

End bellows (not shown) are attached to both ends of the vacuum duct 44 for accommodating a plurality of cartridges. The end bellows is connected to an external device (not shown). The drive mechanism 24 similar to that of the third embodiment is provided on one side surface of the vacuum duct 44 for accommodating a plurality of cartridges. Thereby, the vacuum duct 44 for accommodating a plurality of cartridges can slide in the X-axis direction.

Three permanent magnet group cartridges 36a-3
6c, the gap distance A3 between the permanent magnet arrays 34a and 35a, the gap distance B3 between the permanent magnet arrays 34b and 35b, and the gap distance C3 between the magnetic pole piece arrays 34c and 35c gradually change. 36
c is selected and set.

In the undulator having such a structure, since a plurality of permanent magnet group cartridges 36a to 36c having different intervals between the permanent magnet arrays are set,
By sliding the vacuum duct 44 for accommodating a plurality of cartridges in the X-axis direction, it is possible to select the pole piece gap distances A3 to C3 at the position where the electron beam passes, and the K value can be made variable although it is stepwise. The wavelength of the electron beam can be changed. Further, since a plurality of cartridges can be set in one set, workability is good. Further, since there is no obstruction between the arrangement of the permanent magnets and the electron beam and the magnetic force of each permanent magnet can be effectively applied to the electron beam, the device can be downsized.

[Brief description of the drawings]

FIG. 1 is a side view of an essential part showing an example of an undulator of the present invention with a partial cross section.

FIG. 2 is a perspective view showing an entire undulator.

FIG. 3 is a partial side view showing a part of another example of the undulator of the present invention as a cross section.

FIG. 4 is a perspective view showing the entire undulator.

FIG. 5 is a side view showing the vicinity of a magnet portion showing another example of the undulator of the present invention.

FIG. 6 is a cross-sectional view of a main part of a vacuum duct.

FIG. 7 is a perspective view of a main part of the undulator.

FIG. 8 is a sectional view of a main part of a vacuum duct showing another example of the undulator of the present invention.

FIG. 9 is a perspective view of a main part showing another example of the undulator of the present invention.

FIG. 10 is a cross-sectional view of a main part.

FIG. 11 is a view showing a structure of a vacuum duct for accommodating a plurality of cartridges showing another example of the undulator of the present invention.

FIG. 12 is a view showing the structure of a vacuum duct showing another example of the undulator of the present invention.

FIG. 13 is a cross-sectional view of a vacuum duct for accommodating a plurality of cartridges showing another example of the undulator of the present invention.

FIG. 14 is a side view of a conventional undulator.

FIG. 15 is a perspective view of a conventional undulator.

[Explanation of symbols]

2, 3, 32a to 32c, 33a to 33c, 34a to 3
4c, 35a to 35c permanent magnet group, 4a, 4b magnet holders 10, 11, 16 base flange, 12 accordion type bellows (bellows), 13, 17 duct body, 14 drive rods, 15 drive bellows (bellows), 18a -18c, 19a-19c pole piece arrangement, 2
4,60 Drive mechanism, 28, 28a to 28c Cartridge support stand (support stand), 29, 29a to 29c Magnetic pole piece group cartridge, 36a to 36c Permanent magnet group cartridge, 40,43 Vacuum duct, 41 Cartridge accommodating vacuum duct ( Vacuum duct), 42,44 Vacuum duct for storing multiple cartridges (vacuum duct), 50,
51 Vacuum duct.

Claims (9)

[Claims] 1. A vacuum duct having an electron beam inlet at one end and an electron beam outlet at the other end; and an electron beam introduced from the electron beam inlet and led out from the electron beam outlet. A pair of permanent magnets arranged in parallel in the vacuum duct in a state where the arrangement direction is shifted along the passage so as to form a periodic magnetic field in the passage, and facing each other across the passage. A magnet group, a pair of magnet holders provided in the vacuum duct for respectively holding the pair of permanent magnet groups, and a pair of magnet holders are moved in a direction to increase or decrease a gap between the pair of permanent magnet groups. An undulator having a drive mechanism for driving the undulator. 2. A vacuum duct having a frame-shaped duct body having an electron beam inlet and an electron beam outlet at both ends and having a pair of opposite sides orthogonal to the passage of the electron beam as openings, It is composed of a pair of base flanges that close the opening of the duct body and a pair of bellows that airtightly connects the pair of base flanges to the duct body, and a pair of magnet holders are attached to the pair of base flanges, respectively. The undulator according to claim 1, wherein the undulator is configured to be moved by the drive mechanism via the pair of base flanges. 3. A duct body, wherein a vacuum duct is provided with an electron beam inlet and an electron beam outlet respectively at both ends, and a pair of base flanges facing each other orthogonal to the passage of the electron beam are respectively provided with openings, A flange for closing each of the openings and a bellows for hermetically connecting the flange to the pair of base flanges. A pair of magnet holders are provided on both sides of the flange integrally with the flange to form the passage. The undulator according to claim 1, wherein the undulator is attached to a drive rod extending in a direction orthogonal to the drive rod and is configured to be moved by the drive mechanism via the drive rod. 4. A vacuum duct having an electron beam inlet at one end and an electron beam outlet at the other end, and an electron beam introduced from the electron beam inlet and led out from the electron beam outlet. A pair of parallel lines that are arranged close to the vacuum duct in a state in which the arrangement direction is shifted along the passage so as to form a periodic magnetic field in the passage, and face each other across the passage. Of the permanent magnet group and a pair of permanent magnet groups facing each other so as to form a magnetic field orthogonal to the passage in the same cycle as the permanent magnet forming a magnetic field orthogonal to the passage in the pair of permanent magnet groups. And a plurality of pairs of magnetic pole pieces arranged in parallel in a direction orthogonal to the magnetic field and the passage in the vacuum duct, and the magnetic field orthogonal to the passage and the passage in the vacuum duct. You An undulator having a drive mechanism for moving the undulator in a direction. 5. A magnetic pole gap positioning plate that defines a gap between opposing inner wall surfaces of the vacuum duct in a magnetic field direction orthogonal to the passage is disposed between adjacent pairs of a plurality of pairs of magnetic pole pieces. The undulator according to claim 4, wherein 6. A vacuum duct having an electron beam inlet at one end and an electron beam outlet at the other end, and an electron beam introduced from the electron beam inlet and led out from the electron beam outlet. A pair of parallel lines that are arranged close to the vacuum duct in a state where the arrangement direction is shifted along the passage so as to form a periodic magnetic field in the passage, and face each other across the passage. Of the permanent magnets and the permanent magnets of the pair of permanent magnets that are arranged to face each other so as to form a magnetic field orthogonal to the passage at the same cycle as the permanent magnet that forms a magnetic field orthogonal to the passage. A pair of magnetic pole piece groups is arranged between a pair of support bases arranged opposite to each other, and a magnetic pole piece group cartridge is detachably mounted in the vacuum duct. Characteristic undulator. 7. The vacuum duct has a plurality of pairs of magnetic pole piece group cartridges in which gaps between different magnetic pole piece groups are arranged side by side in the vacuum duct in a direction perpendicular to a magnetic field orthogonal to the passage and a direction orthogonal to the passage. 7. The undulator according to claim 6, wherein the undulator is configured to be movable in a magnetic field orthogonal to the passage and a direction orthogonal to the passage. 8. A vacuum duct having an electron beam inlet at one end and an electron beam outlet at the other end, and an electron beam introduced from the electron beam inlet and led out from the electron beam outlet. So that a periodic magnetic field is formed in the passage, the arrangement direction is shifted along the passage, and they are arranged facing each other across the passage with different gaps, respectively, in the vacuum duct. A magnetic field orthogonal to the passage of the periodic magnetic field and a plurality of pairs of permanent magnets arranged in parallel in a direction orthogonal to the passage, and the magnetic field orthogonal to the passage and the direction perpendicular to the passage and the vacuum duct. An undulator having a drive mechanism for moving the undulator. 9. The array direction along which the permanent magnet groups of each pair are arranged so as to form a periodic magnetic field in the passage of the electron beam between a pair of supporting stands arranged opposite to each other. 9. The undulator according to claim 8, wherein the undulator is composed of permanent magnet group cartridges that are arranged in a state where they are displaced and are opposed to each other with the passage being interposed therebetween.