JPH03145100A - Undulator for electron beam - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electron beam undulator for meandering an electron beam used in a synchrotron radiation generation device or a free electron laser oscillation device.

[Prior Art] An electron beam undulator provided in a synchrotron radiation device or a free electron single laser oscillation device is
As shown in the figure, a band-shaped - with a rectangular cross-section in which a plurality of conductors are bundled - is tightly attached to the outer circumferential surface of a cylindrical vacuum duct 1 through which electrons pass through the central part whose interior is kept in a vacuum state. Alternatively, a plurality of helical coils 2 are wound spirally toward the center axis of the duct 1 while maintaining appropriate intervals so as not to cross each other. On the outer peripheral surface side of the duct l excluding the part of the helical coil 2, there is a helical coil 2 that is in close contact with the outer peripheral surface and concentric with the vacuum duct l.
A support tube 3 having an outer diameter that does not bury the support tube 3 is provided,
These support tubes 3 fix each helical coil 2.

[Problems to be Solved by the Invention] However, in such a conventional electron beam undulator, the electrons travel in a meandering manner through the central part of the interior of the duct 1, and the electron beam forming range 4 is formed within the range through which the electrons pass.
However, the diameter of this electron beam forming range 4 tends to gradually widen along the central axis direction of the undulator, resulting in a problem that the intensity of the synchrotron radiation obtained from the undulator decreases. .

The present invention has been made to solve these problems, and an object of the present invention is to provide an undulator for electron beams that does not reduce the intensity of synchrotron radiation.

[Means for Solving the Problems] The present invention provides a method in which one or more helical coils are spirally wound in the direction of the central axis of the duct without crossing each other on the outer peripheral surface side of the duct through which electrons pass through the cavity. The electron beam undulator is characterized by having conductors extending parallel to each other at four positions dividing the circumferential direction of the duct into four equal parts between the outer peripheral surface of the duct and the helical coil.

[Function] With this configuration, the four conductors converge the electron beam formed by the electrons passing through the duct to the center of the duct, and the synchrotron radiation obtained from the electron beam undulator. Acts to increase strength.

[Embodiment] In FIG. 1 showing an embodiment of the electron beam undulator of the present invention, the same components as in FIG. 6 are designated by the same reference numerals, and the explanation thereof will be omitted.

A straight conductor 5 (straight conductors 5-1 to 5 to be described later), which has a rectangular cross section by bundling a plurality of conductors, is located on the outer circumferential surface side of the duct l and at a position that divides the outer circumferential surface into four equal parts in the circumferential direction. −
4) is provided in parallel to the central axis direction of the duct 1 in close contact with the outer circumferential surface. In addition, the straight conductors 5 provided at opposite positions across the duct l
Make sure that the current flows in the same direction. For example, as shown in FIG. 2, the straight conductors 5-1. In the straight conductors 5-3, 5-4 provided on the left and right sides of the duct 1, a current is passed from the back side of the paper toward the front side, as shown in the current direction 7. Straight conductor 5 installed in this way and through which current flows
is an electron beam formed by electrons that meander through the inside of duct 1. This is to converge in the vertical direction at the center.

The outer circumference side of the duct 1 is filled with mold resin 8 so as to form a circumferential surface concentrically with the duct l with a thickness approximately equal to the height of the straight conductor 5 in the diametrical direction of the duct l. A straight conductor 5 is fixed to the outer circumferential surface of the duct l using molded resin 8.

Furthermore, on the outside of the cylindrical body formed of the molded resin 8 and the straight conductor 5, a cylindrical support tube 3 is provided concentrically with the duct 1, as in the conventional example, and this support tube 3 has - or multiple Two helical coils are provided. In this embodiment, the helical coils 2 are provided at respective positions that divide the circumferential direction of the support cylinder 3 into three equal parts, and the helical coils 2 are conductors that are made up of a plurality of conductors bundled and have a rectangular cross section. .

Further, both the helical coil 2 and the linear conductor 5 may be formed of superconducting conductors.

The operation of the electron beam undulator configured in this manner will be described below.

Electrons pass through such an undulator while meandering, and the passing electrons form an electron beam in the electron beam forming area 4.
is formed. Furthermore, by passing current through the four straight conductors 5 in the directions mentioned above, the electron beam forming range 4
A quadrupole magnetic field is generated. Therefore, the magnetic force of this quadrupole magnetic field acts on the electrons passing through the undulator, and the duct 1
A converging force acts on the central part of . Therefore, the diameter of the electron beam forming range 4 does not increase, and synchrotron radiation light with high intensity can be obtained.

As an installation example of the electron beam undulator configured as described above, as shown in FIG. 3(a), for example, two electron beam undulators A and B are installed in the duct of each component l are concentrically connected in series. The direction of the current flowing through the straight conductors 5-1 to 5-4 provided in the electron beam undulator A is as shown in FIG.
For -2, the direction is from the back side of the paper to the front side, and for straight conductors 5-3 and 5-4, the direction is from the front side to the back side of the paper. On the other hand, the direction of the current flowing through the straight conductors 5-1 to 5-4 provided in the electron beam undulator B is the same as that shown in FIG. That is, in the straight conductors 5-1 to 5-4 in the electron beam undulator A and the electron beam undulator B, the angles at which the straight conductors are provided on the outer peripheral surface of the duct 1 are the same, but the direction of the flowing current is different. are different from each other, and current flows in the same direction between straight conductors installed at positions 90 degrees apart from each other.

In this way, the direction of the current is set by the electron beam undulator A.
By changing and B, in the electron beam undulator A, in the left and right direction along the central axis direction of the duct l,
Since the electron beam undulator B can converge electrons in the vertical direction along the central axis of the duct l, the electron beam undulators A and B can converge the electrons at the center of the duct l. can.

FIG. 5 is a diagram showing another embodiment of the electron beam undulator of the present invention, in which four conductors 1O-1 to LO-4 are provided on the outer peripheral surface of the duct 1. Although not shown in FIG. 5, the helical coil 2, support tube 3, and mold resin 8 shown in FIG. 1 are also provided.

In the electron beam undulator of this embodiment, there are four conductors 1 in the entire length of the electron beam undulator 20.
0 (hereinafter collectively referred to as the conductors 10-1 to 10-4) is twisted 90 degrees between the entrance and exit of the electron beam undulator. The conductor 10-1 installed at the duct 1100 degrees at the entrance 0IlIA of the electron beam undulator 20 is at the 90 degree position of the duct l at the exit side B of the electron beam undulator 20, that is, at the O angle mentioned above. The electron beam undulator 20 is installed in a spiral shape so as to make a quarter turn on the outer peripheral surface of the duct 1 along the longitudinal direction of the electron beam undulator 20 so as to be at a position rotated by 90° in the circumferential direction of the duct.

Similarly, the entrance side A of the electron beam undulator 20
, the conductor 10- installed in the duct 1 at a 90 degree shifted position.
2 is a conductor 1 located at a position displaced by 180 degrees from the duct 1 on the outlet side B, and located at a position displaced from the duct 1 by 180 degrees at the entrance side A.
0-3 is about 270 degree displacement of duct I on exit side B,
Conductor 10-4, located 270 degrees displaced from duct 1 at inlet ff1ll A, is located at the outlet (in jlIIB, duct l
It is installed so that it is at the 0 displacement position.

Then, the conductors 10-1 to 10 installed in this way
-4, current is caused to flow in mutually adjacent conductors such that the directions of current flow are opposite to each other. By installing the conductors 1O-1 to 1O-4 in this way and making the direction of the current different, for example, on the entrance side A of the electron beam undulator 20, electrons are transferred to the central axis of the duct 1 at the center of the duct 1. On the other hand, on the exit side B, electrons are focused in the vertical direction with respect to the central axis direction of the duct L at the center of the duct L. Therefore, over the entire length of the electron beam undulator 20, electrons are converged at the center of the duct 1.

In each of the above-mentioned embodiments, the electron beam undulator in which the duct l extends in a straight line has been described, but the duct l extends linearly.
It can also be applied to an electron beam undulator whose curve is arcuate.

[Effects of the Invention] As detailed above, according to the present invention, the electron beam passing through the duct can be focused at the center of the duct by the magnetic field generated by the conductor provided on the outer peripheral surface ζ of the duct. The intensity of synchrotron radiation obtained from the electron beam undulator does not decrease.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the electron beam undulator of the present invention, FIG. 2 is a cross-sectional view of the electron beam undulator shown in FIG. 1, and FIG. Side view showing an example of installing a beam undulator, 3rd
Figure (b) is a diagram showing the angle on the outer peripheral surface side of the electron beam undulators A and B shown in Figure 3 (a), and Figure 4 is a diagram showing the straight conductor of the electron beam undulator A shown in Figure 3 (a). FIG. 5 is a perspective view showing another embodiment of the electron beam undulator of the present invention,
FIG. 6 is a perspective view showing a conventional electron beam undulator. l...Duct, 2...Helical coil, 5...Straight conductor, 8...Mold resin. Figure 1

Claims (5)

[Claims] (1) In an electron beam undulator in which one or more helical coils are spirally wound in the direction of the central axis of the duct without intersecting the outer circumferential surface of the duct through which electrons pass through the cavity, the outer circumferential surface of the duct and An undulator for an electron beam, comprising conductors extending parallel to each other at four positions dividing the circumferential direction of a duct into four equal parts between the helical coil and the helical coil. (2) The electron beam undulator according to claim 1, wherein the conductor is parallel to the axis of the duct. (3) An electron beam undulator, characterized in that the conductor is twisted at 90 degrees on the outer peripheral surface of the duct over the entire length of the duct with respect to the central axis of the duct. (4) The gaps formed in the circumferential direction of the duct by each of the conductors provided on the outer peripheral surface of the duct are filled with resin so that a circumferential surface concentric with the duct and inscribed with each of the conductors is formed. 4. The electron beam undulator according to claim 1, wherein the helical coil is provided on a circumferential surface formed on the undulator. (5) The electron beam undulator according to any one of claims 1 to 4, wherein the helical coil and the conductor are made of a superconducting conductor.