JPH06275428A - Undulator - Google Patents

Abstract

PURPOSE:To provide an undulator capable of reducing the number of magnet arranged in order to generate a transverse wave on an orbit of electrons and miniaturing a device. CONSTITUTION:A plurality of first magnets 11 are arranged at constant intervals, and also a plurality of second magnets 12 are arranged opposed to each first magnet 11, and in each first magnet 11 and each second magnet 12, different poles are opposed to each other. An alternating magnetic field is formed between each first magnet 11 and each second magnet 12. Electrons are accelerated by means of a cyclotron clotron and introduced to pass through this alternating magnetic field, then a transverse wave is generated on an orbit of electrons, whereby electromagnetic waves are radiated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undulator that generates transverse waves in the orbit of accelerated electrons and thereby emits electromagnetic waves.

[0002]

2. Description of the Related Art Conventionally, in this type of device, two rows of magnet groups 101 and 102 are arranged to face each other as shown in FIG. 6, and these magnet groups 101 and 102 are arranged on the Z axis in the figure. Each magnet 104 that emits magnetic force lines in a direction substantially orthogonal to each other
Then, the respective magnets 105 for emitting magnetic force lines are arranged alternately in a direction substantially along the Z axis. As a result, an alternating magnetic field is formed between the two groups of magnets 101 and 102. Electrons accelerated by a cyclotron, a linac, etc. are guided to the alternating magnetic field, and when passing through the alternating magnetic field, transverse waves are generated in the orbits 103 of the electrons, thereby radiating electromagnetic waves. Here, the wavelength λ of the transverse wave corresponds to the length of the four magnets arranged in the magnet group.

Further, in the apparatus shown in FIG. 7, for each of the two groups of magnets 111 and 112, each magnet 114 that emits magnetic force lines in a direction substantially along the electron trajectory 113 and each magnetic body 115 having high magnetic permeability. And are alternately arranged, whereby an alternating magnetic field is formed between the two groups of magnets 111 and 112. Here, the wavelength λ of the transverse wave generated in the electron trajectory 113 corresponds to the length of the two magnets and the two magnetic bodies arranged in the magnet group.

Each device shown in FIGS. 6 and 7 has an "N"
uclear Instruments and Methods in Physics Research
"HYBRID UNDULATOR DES" described in A250 (1986) 100-109 "
IGNCONSIDERATIONS ".

On the other hand, in the apparatus shown in FIG. 8, a first bias magnet 121 having an N pole and a second bias magnet 122 having an S pole are arranged so as to face each other, and the first bias magnet 121 is arranged. A non-magnetic layer 123 is provided on the second bias magnet 122, and a non-magnetic layer 124 is provided on the second bias magnet 122. A plurality of magnets 125 are arranged on the non-magnetic layer 123 at regular intervals.
4, a plurality of magnets 126 are arranged at regular intervals. An alternating magnetic field is formed between the non-magnetic layers 123 and 124, and a transverse wave is generated in the orbit of the electrons passing therethrough.

The device shown in FIG. 8 is a "MICROPOLE UNDULATOR" of "Patent Number: 4800353" filed in the United States.
Is shown in.

[0007]

By the way, in each of the conventional devices shown in FIGS. 6 and 7, one wavelength λ of the transverse wave generated in the electron orbit is at least four magnets (including the magnetic substance 115). Equivalent to. Therefore, a total of eight magnets must be arranged for each cycle of the transverse waves in the two groups of magnets facing each other via the electron trajectories, and for this reason, a very large number of magnets are arranged in the entire apparatus. I decided to do it.

Further, in the conventional apparatus shown in FIG. 8, one cycle of the transverse wave of electrons is formed for each pair of magnets 125 and 126. Therefore, the number of magnets arranged is larger than those of the above two apparatuses. Is only 1/4. However, this device requires a bias magnetic field and requires two bias magnets 1.
Since the device 21 and 122 must be provided, the size of the device is increased.

Therefore, an object of the present invention is to provide an undulator capable of reducing the number of magnets arranged to generate transverse waves in the orbits of electrons and reducing the size of the device.

[0010]

In order to solve the above problems, in the present invention, one of the N pole and the S pole is arranged at a predetermined interval toward the orbit of the electron. A plurality of first magnets, and a plurality of second magnets in which the other pole of the N pole and the S pole is arranged to face each of the first magnets through the orbits of the electrons. Composed.

[0011]

According to the present invention, each of the first magnets and each of the second magnets have poles different from each other, and are opposed to each other via the orbits of electrons. Therefore, the pair of first and second
A magnetic force line in one direction is generated between the magnets. Also, the first
Since the other poles of the second magnet and the second magnet are also different, magnetic field lines in opposite directions are generated between these poles through the sides of the first and second magnets. Therefore, two lines of magnetic force lines are generated for each pair of the first magnet and the second magnet.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described with reference to FIG.

As shown in FIG. 1 (a), two infinitely wide flat plate-shaped magnets 1 and 2 are arranged opposite to each other, and the upper surfaces of these magnets 1 and 2 serve as S poles and the lower surface thereof has N poles. It is assumed that these magnets 1 and 2 are magnetized so as to form a pole.
In this case, the magnetic field line A changes from the north pole of the magnet 1 to the south pole of the magnet 2.
Occurs. A magnetic force line B is generated from the N pole of the magnet 2 to the S pole of the magnet 1, and the magnetic force line B is generated vertically because the magnets 1 and 2 are infinitely wide. Therefore, the respective magnetic force lines A and B are generated in the completely opposite directions and cancel each other out.

On the other hand, if the two flat plate-shaped magnets 1 and 2 are finite on the right side as shown in FIG. 1B, the magnetic field line B from the N pole of the magnet 2 to the S pole of the magnet 1 is shown. Represents an arc, the magnetic field lines A and B do not cancel each other and coexist. At this time, the strength and direction of the magnetic field between the magnets 1 and 2 are
It changes as shown in the graph of FIG. In this graph, the z-axis represents the position on the line passing through the center between the magnets 1 and 2, and the y-axis represents the strength and direction of the magnetic field between the magnets 1 and 2. As is clear from this graph, the magnetic field is reversed with the change in the position between the magnets 1 and 2 in the right direction.

Similarly, if the two flat plate-shaped magnets 1 and 2 are finite on the left side as shown in FIG. 1D, the magnetic force lines B also form an arc here, so that the magnetic force lines A and B coexist. To do. Further, as is clear from the graph of FIG. 1E, the strength and direction of the magnetic field are reversed as the position of the magnets 1 and 2 moves leftward.

Although not shown, in the vicinity of the end of one magnet, lines of magnetic force are generated between the two poles of the magnet.

FIG. 2 (a) schematically shows an embodiment of the undulator according to the present invention. In the undulator of this embodiment, a plurality of first magnets 11 are arranged at regular intervals, and a plurality of second magnets 12 are arranged in each first.
Are arranged to face the magnets 11 of the
The first and the second magnets 12 have different poles facing each other. Of course, the electrons will pass through the center between each first magnet 11 and each second magnet 12 along the z-axis.

Now, a pair of first and second magnets 1 facing each other.
Between lines 1 and 12, magnetic force lines A shown in FIGS. 1B and 1D are generated. 1B is generated at the right ends of the first and second magnets 11 and 12, and FIG. 1D is generated at the left ends of the first and second magnets 11 and 12. Magnetic field line B shown in
Occurs. Therefore, the strength and direction of the magnetic field between each first magnet 11 and each second magnet 12 change as shown in the graph of FIG. As is clear from these FIGS. 2A and 2B, the pair of first and second magnets 11 and 12
To one of the other pair of first and second magnets 11 and 12, one cycle of the magnetic field is formed. From this, it is preferable that the thickness a of the first and second magnets 11 and 12 is equal to the arrangement interval b of the first magnets 11 and the second magnets 12 (a = b).

Here, one cycle of the magnetic field forms one cycle of transverse waves of electrons passing through this magnetic field. Further, since one cycle of the magnetic field is formed for each of the pair of first and second magnets 11 and 12, two magnets are required for each wavelength λ of the transverse wave of electrons. Therefore, in comparison with the conventional devices shown in FIGS. 6 and 7, the undulator of this embodiment requires only 1/4 the number of magnets. Further, unlike the conventional apparatus shown in FIG. 8, a bias magnet is not required,
There is an advantage that the size of the device is not increased.

FIG. 3 illustrates a structure for supporting each first magnet 11. As shown in this FIG. 3, these first magnets 11 are made of non-magnetic material plate 1 with an adhesive.
3 are arranged and fixed. Further, one flat magnet may be fixed on the non-magnetic plate 13 with an adhesive, and thereafter the flat magnet may be divided by an etching treatment to form each first magnet 11. Absent. In the case of this etching process, a large number of magnets can be easily formed and arranged. Of course, each second magnet 12 is also arranged on the non-magnetic plate in the same manner as each first magnet 11.

FIG. 4 schematically shows another embodiment of the undulator according to the present invention. In this example,
A flat plate-shaped first magnet 21 and a flat plate-shaped second magnet 22 are arranged to face each other. Below the first magnet 21, a plurality of magnet pieces 21a are arranged, and these magnet pieces 21a are formed by etching. Similarly, on the upper side of the second magnet 22, a plurality of magnet pieces 22a formed by the etching process are arranged. In addition, in the first magnet 21, each magnet piece 21
Each area between a and is irradiated with a laser beam and is once heated until it exceeds the Curie point, so that each area is demagnetized. Similarly, also in the first magnet 21, the respective areas between the magnet pieces 22a are once heated by the laser beam until the Curie point is exceeded,
It has been degaussed. Therefore, an alternating magnetic field shown in FIG. 2B is generated between each magnet piece 21a and each magnet piece 22a, similarly to the undulator shown in FIG. 2A.

Here, each magnet piece 21a is connected above the first magnet 21 and below the second magnet 22.
Since the magnet pieces 22a are connected to each other, a non-magnetic plate for arranging and fixing the magnet pieces 21a and the magnet pieces 22a is not required.

FIG. 5 schematically shows another embodiment of the undulator according to the present invention. In this example,
A flat plate-shaped first magnet 31 and a flat plate-shaped second magnet 32 are arranged so as to face each other, and the first magnet 31 is connected to each magnetic force holding area 3
1a and each demagnetization area 31b, the second magnet 32 is divided into each magnetic force holding area 32a and each demagnetization area 32b, and each demagnetization area 31b of the first magnet 31 and each demagnetization of the second magnet 32. The area 32b is previously demagnetized. First
The magnet 31 and the second magnet 32 are made of a material having a small magnetic permeability, so that the magnetic lines of force of each degaussing area are drawn so as to resemble the magnetic lines of space.
An alternating magnetic field is generated between 1 and 32.

To degauss each degaussing area 31b of the first magnet 31 and each degaussing area 32b of the second magnet 32,
A laser beam is applied to these degaussing areas similarly to the undulator shown in FIG. In this case, since only the flat plate-shaped magnet is irradiated with the laser beam, it is possible to make a striped pattern in which each magnetic force holding area and each demagnetization area are alternately arranged.

[0025]

As described above, according to the present invention, each of the first magnets and each of the second magnets are arranged so as to face each other with their different poles facing each other through the orbits of the electrons. Magnetic lines of force in two directions are generated by the first magnet and the second magnet. Therefore, for each pair of the first magnet and the second magnet,
One cycle of transverse wave is formed in the orbit of the electron. Therefore, in comparison with the conventional devices shown in FIGS. 6 and 7,
In the undulator according to the present invention, the number of magnets is 1/4.
It's done. Further, there is an advantage that a bias magnet is not required unlike the conventional apparatus shown in FIG. 8 and the apparatus does not become large.

[Brief description of drawings]

FIG. 1 is a diagram used to explain the principle of the present invention.

FIG. 2 is a diagram showing an embodiment of an undulator according to the present invention.

3 is a perspective view partially showing the structure in the embodiment of FIG.

FIG. 4 is a diagram showing another embodiment of the undulator according to the present invention.

FIG. 5 is a diagram showing another embodiment of the undulator according to the present invention.

FIG. 6 is a diagram showing an example of a conventional device.

FIG. 7 is a diagram showing another example of a conventional device.

FIG. 8 is a diagram showing another example of a conventional device.

[Explanation of symbols]

 11, 21, 31 First magnet 12, 22, 32 Second magnet 13 Non-magnetic body

Claims (4)

[Claims] 1. An undulator that forms an alternating magnetic field in a passage area of electrons and generates transverse waves in the orbits of the electrons, wherein one of N pole and S pole is predetermined toward the orbit of the electrons. A plurality of first magnets arranged at different intervals, and a plurality of second magnets arranged so that the other pole of the N pole and the S pole faces each of the first magnets through the orbit of the electrons. An undulator with a magnet. 2. Each of two flat plate-like magnets facing each other through the orbit of the electrons is divided into a plurality of magnets by an etching process, thereby forming each of the first magnets and each of the second magnets. The undulator according to claim 1. 3. The undulator according to claim 2, wherein in each of the flat plate-shaped magnets, a front surface side facing the orbit of the electrons is divided by etching treatment and a back surface side is connected. 4. The two flat plate-shaped magnets facing each other through the orbit of the electrons are divided into magnetic field holding areas and degaussing areas that are alternately arranged, and these degaussing areas are heated to a Curie point or higher. The undulator according to claim 1, wherein the undulator is demagnetized to thereby form the first magnets and the second magnets.