JPH05226144A - Undulator - Google Patents

Abstract

PURPOSE:To achieve an undulator where a permanent magnet is fixed to a magnet holder firmly by providing a deformed part at the edge part of the permanent magnet changing the shape of the magnet holder to fit the deformed part, embedding both of them and then fixing them, and laying them out along the track of an electron beam so that a periodic magnetic field is generated. CONSTITUTION:A square projecting part is formed at the tip part in longer direction of a projection-type permanent magnet 7a for center part and a center part projection-type magnet holder 8a is shaped to the permanent magnet 7a. The permanent magnet 7a is inserted form the side of the magnetic holder 8a, both of them are embedded without any gap, and they are screwed firmly. Then, the permanent magnet is laid out while the direction of magnetization is shifted by 90 degrees, thus aligning these permanent magnets periodically for creating a full periodical magnetic field on the center axis of an undulator without any deterioration of magnetic characteristics due to heating for curing an adhesive, aging of the adhesive, or a deterioration due to radiation light.

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 an accelerator using synchrotron radiation, and more particularly to an undulator having a plurality of permanent magnets arranged along an electron beam duct.

[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 hundreds of millions of electron volts (hundreds of MeV)
When the orbit of an electron that is accelerated to the above high energy state and moves in a vacuum at almost the speed of light is bent, light called synchrotron radiation is emitted in the tangential direction of the orbit.

The emitted light by this synchrotron radiation is continuous light with 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 for spectrally using a narrow wavelength range. If the wavelength is shortened in order to meet this demand, then the intensity of the radiated light will decrease, and a high-luminance light source cannot be obtained. Therefore, in order to satisfy the demands for shorter wavelength and higher brightness, undulator radiation by an undulator (electronic meandering device), which is one of the insertion type light sources, has been studied and used.

The undulator is a periodic magnetic field generator, which emits high-intensity radiant light by injecting electrons into the undulator to cause meandering motion and interfering radiant light emitted for each meandering. be able to. However, if the meandering orbit of the electron is slightly distorted, the interference of the radiated light emitted by each meandering becomes insufficient and the brightness of the radiated light is extremely reduced, so the undulator magnetic field requires high accuracy. .

FIG. 11 shows a longitudinal magnet array of a conventional undulator. 12 is a view taken along the line XII-XII in FIG. 11, and FIG. 13 is a view taken along the line XIII-XIII in FIG. In these figures, 1a is a rectangular parallelepiped permanent magnet for the central portion, 1b is a permanent magnet for the end portion having a width half that of the permanent magnet for the central portion, and the arrows in the drawings indicate the direction of magnetization. Two
a is a center magnet holder, 2b is an end magnet holder, 3a is a center magnet holder support, 3b, 3c
Is an end magnet holder support, and 4 is a mount.

The permanent magnets 1a are attached to the magnet holders 2a one by one.
Then, it is fixed to the magnet holder support 3a to form a central block by fixing the same with an adhesive and changing the direction of magnetization by 90 ° as shown in FIG.

The width of the magnet holder 2a is smaller than that of the permanent magnet 1a as shown in FIG. 12 because the magnets are arranged without a gap and the undulator magnetic field has a precise periodic length to be a complete periodic magnetic field, which in turn causes the meandering of electrons. This is to eliminate the distortion of the orbit.

At one end, one of the three center permanent magnets 1a is fixed to the center magnet holder 2a with an adhesive, and the other end permanent magnet 1b is one end magnet holder 2b. The one fixed to the end magnet holder support 3b, and the other one fixed four center permanent magnets 1a to the center magnet holder 2a, and one end permanent magnet 1b for the end. The one fixed to the magnet holder 2b is fixed to the end magnet holder support 3c to form an end block.

In this manner, a large number of center magnet holder supports are fixed to the center portion, and one end magnet holder support is fixed to the gantry 4 at both ends. An undulator is constructed by assembling these magnet arrays one above the other. Regarding the depth direction of the paper, the permanent magnets 1a and 1b have a length of, for example, about 10 cm, and the electron beam passes through the center of the depth of the magnet in the horizontal direction of the paper. Reference numeral 5 denotes a periodic magnetic field, and the electron beam 7 changes its amplitude according to the change of the periodic magnetic field, and travels along the central axis while meandering in the depth direction of the paper.

[0010]

In manufacturing a conventional undulator, after applying an adhesive between the permanent magnet and the magnet holder, the permanent magnet and the magnet are heated for several tens of hours with the temperature raised to about 100 ° C. It is necessary to fix the holder. This is to increase the adhesive force so that the permanent magnets will not come off from the magnet holder due to the strong magnetic force between the permanent magnets. However, when exposed to a temperature of 100 ° C for a long time,
The magnetic field characteristics of the permanent magnet change, and it becomes impossible to obtain a precise undulator magnetic field. Further, when the permanent magnet and the magnet holder are fixed by using the adhesive, there is a possibility that the adhesive itself may deteriorate with time or deteriorated by the emitted light.

According to the present invention, the permanent magnets are strongly fixed to the magnet holder without using an adhesive, and these permanent magnets are periodically arranged to form a complete periodic magnetic field on the central axis of the agitator. Electrons passing on the central axis undergo a meandering motion without distortion due to the magnetic field, and as a result, the radiated light emitted by each meandering interferes completely, providing an undulator capable of obtaining high-brightness radiated light. The purpose is to

[0012]

In order to achieve the above object, in the present invention, a deformable portion such as a convex shape, a concave shape or a tapered shape is provided at the tip of the facing surface of the permanent magnet, and the magnet holder is The permanent magnet is shaped so as to fit the deformed portion, and the two are fitted without any gaps and then firmly fixed by being screwed so that a periodic magnetic field is generated along the trajectory of the electron beam.

[0013]

In this way, since the permanent magnet can be fixed to the magnet holder without using an adhesive, deterioration of the magnetic characteristics of the permanent magnet, aging of the adhesive, deterioration due to radiant light, etc. does not pose a problem.

[0014]

Embodiments of the undulator of the present invention will be described below with reference to FIGS.

FIG. 1 is a view as seen from the same direction as FIG. 12, and FIG. 2 is a view as seen from the arrow II-II in FIG. The convex permanent magnet 7a for the central portion has a square convex portion as shown in FIG. 1 at the tip portion in the longitudinal direction, and the holder 8a for the central convex magnet 7a is shaped to fit the permanent magnet 7a. The permanent magnet 7a is inserted from the side of the magnet holder 8a, and the permanent magnet 7a is fitted into the magnet holder 8a without any gap, and then the screw is firmly tightened with a screw. Thereby, the permanent magnet 7a and the magnet holder 8a can be firmly fixed to each other without using an adhesive.

The permanent magnets are arranged so that the directions of magnetization are shifted by 90 °, but in the example of FIG. 1, the cross section of the permanent magnet 7a is square, and the projections are also square, so the permanent magnet 7
a can be arranged in an arbitrary direction of magnetization and is versatile. Since the permanent magnet has a large variation in magnetization, it is necessary to devise, for example, arranging those having uniform magnetization at positions where the magnetization direction is upward or downward, and the versatility of the permanent magnet is important. (Other embodiments)

In the above embodiment, the permanent magnet has a square convex portion. However, the convex portion of the permanent magnet may have any shape as long as it can be easily screwed. In FIGS. This is an embodiment in the case of a regular square cone and has the same versatility as the embodiment of FIG.

In the case of a permanent magnet whose direction of magnetization is fixed, it is not necessary to deform the four sides, and it is sufficient to provide a cut portion only on one side. For example, FIGS. 5 and 6 show an embodiment in which a taper portion is provided only on one side, and FIGS. 7 and 8 show an embodiment in which a notch portion is provided at a right angle on only one side.

It is also possible to provide the permanent magnet with a recess. For example, FIGS. 9 and 10 show an embodiment in which a round recess is provided in the permanent magnet. 9 is a sectional view taken along line IX-IX in FIG. 11, and FIG. 10 is a view taken along line XX in FIG. In this case, the permanent magnet 7c is sandwiched between the magnet holders 8d and 8e, and the permanent magnets 8d and 8e are fastened with screws in the longitudinal direction of the permanent magnet.

[0020]

According to the present invention, in the undulator, the longitudinal end of each permanent magnet has a convex shape, a concave shape,
By using a taper shape, etc., the permanent magnet can be fixed to the magnet holder without using an adhesive, and deterioration of magnetic properties due to heating for hardening the adhesive, deterioration of the adhesive over time, and deterioration by radiant light. , The permanent magnets are periodically arranged to create a complete periodic magnetic field on the central axis of the undulator, and this periodic magnetic field causes the electrons passing on the central axis to meander without distortion, resulting in Thus, it becomes possible to provide a high-performance undulator in which the radiated light emitted for each meander completely interferes with each other to obtain a radiated light with high brightness.

[Brief description of drawings]

FIG. 1 is a diagram of an undulator according to a first embodiment of the present invention.

2 is a view taken along the line II-II in FIG.

FIG. 3 is a diagram of a second embodiment of the present invention.

FIG. 4 is an IV-IV arrow view of FIG.

FIG. 5 is a diagram of a third embodiment of the present invention.

6 is a VI-VI arrow view of FIG.

FIG. 7 is a diagram of a fourth embodiment of the present invention.

FIG. 8 is a view on arrow VIII-VIII of FIG.

FIG. 9 is a diagram of a fifth embodiment of the present invention.

FIG. 10 is a view on arrow XX in FIG.

FIG. 11 is a side view of a conventional undulator.

FIG. 12 is a view on arrow XII-XII in FIG.

13 is a view on arrow XIII-XIII in FIG.

[Explanation of symbols]

 1a ... Permanent magnet for center 1b ... Permanent magnet for end 2a ... Magnet holder for center 2b ... Magnet holder for end 3a ... Magnet holder support for center 3b, 3c ... Magnet holder support for end 4 ... Stand 5 ... periodic magnetic field 6 ... electron beam 7a ... convex permanent magnet for central part 7b ... tapered permanent magnet for central part 7c ... notched permanent magnet for central part 7d ... concave permanent magnet for central part 8a ... convex central part magnet Holder 8b ... Central tapered magnet holder 8c ... Central notched magnet holder 8d, 8e ... Central concave magnet holder

Claims (1)

[Claims] 1. A deformable portion of a permanent magnet, wherein a plurality of substantially rectangular parallelepiped permanent magnets are provided with a deforming portion such as a convex shape, a concave shape, a taper shape, etc. on opposite surfaces thereof, and the magnet holder is shaped to fit the deforming portion. The undulator is characterized in that the is fixed by pressing against opposite portions of the magnet holder with screws, and these are arranged so as to generate a periodic magnetic field along the trajectory of the electron beam.