JPS6220300A - Charged particle apparatus - 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] This invention relates to a charged particle device, and more specifically, to a synchrotron, a storage ring, etc., which are accelerators for charged particle beams such as electron beams. It relates to charged particle devices.

[Conventional technology]

The charged particle device mentioned here includes a synchrotron and a storage ring, and the storage ring will be taken up in the following explanation. Further, as a charged particle beam, a typical electron beam will be explained as an example.

Traditionally, this type of technology has been referred to as "electronics".
Magazine, July 1963 issue, P, 2,! 1--P, 3
It is also described in t.

Figure 3 shows a conventional storage ring (10), with an inflector (, 2) placed at the incident position of the electron beam (1).
) along a balanced trajectory (3) passing through the electron-focusing quadrupole electromagnets (4), a plurality of deflection electromagnets (5) that deflect the electrons, and a bump magnet (6) that generates a high-speed pulsed magnetic field.
and a high frequency cavity (7) that generates a high frequency electric field. (r) is linear free space along the equilibrium trajectory (3).

The storage ring (10) having the above configuration allows a high-energy electron flux to orbit along a predetermined equilibrium orbit (3), and also allows a high-energy electron flux to circulate for a period of several hours to several 70 hours 11fi. Its kinetic energy is used to keep it held. Seven uses of the storage ring (10) include synchrotron radiation, which is emitted when a high-energy electron flux orbits a predetermined equilibrium orbit (3), so it can be used for ultra-LSI exposure. There is a light source for Usually, an accelerator such as a well-known linear accelerator or a synchrotron is provided upstream of the storage ring (10), and the electron beam (1) is sent from the upstream accelerator and sent to the storage ring (10). It is introduced into the storage ring (/θ) via an inflector (2) provided in a part of the linear free space (r).

Linear free space (t) means a space without magnetic or electric fields, and this space includes an inflector (2), a bump electromagnet (A), and a high-frequency cavity (RI) with the following functions.
etc. are installed.

In Fig. 3, the high-energy electron flux orbiting stably in the storage ring (10) orbits in an equilibrium orbit (3) with a weakly converging magnetic field distribution, but the electron beam (1) orbits in linear free space ( The equilibrium trajectory (3) in f) forms a predetermined angle. The electron beam (1) after passing through the inflector (, 2), which has a center of curvature on the opposite side to the center of curvature of the bending electromagnet (j), is emitted from the inflector (2) parallel to the equilibrium orbit (3). storage ring (10)
introduced into the world. Furthermore, as is well known, the inflector (
2) has a negative electrode and an anode, and achieves a predetermined deflection of the electron beam (1) by the electric field generated between them. It is based on a structure with

The electron beam (1) exiting the inflector (, 2) is parallel to the equilibrium orbit (3), but with a certain amount of displacement, the cross section of the electron flux is The center vibrates and collides with a vacuum container (not shown) containing the electron flux, causing some of the electron flux to be lost.

The amplitude of the above vibration is equal to the above displacement amount that the electron beam (1) has when it exits the inflector (, 2).

Therefore, the electron beam (,
1) exhibits a tendency for the electron flux center amplitude to decrease and intersects the equilibrium trajectory (3). If it is possible to make the angular change between 1B·(7) and the equilibrium orbit (7) O at this intersection point, which is encountered for the first time after incidence, the loss of electron flux can be minimized. In the example of Figure 3, a bump electromagnet (6) is installed at this intersection, and the bump electromagnet (6) generates a fast pulsed magnetic field to achieve the above purpose. The temporal speed of this high-speed pulsed magnetic field is required here to be such that, for example, after the electron flux passes, the magnetic field of the bump electromagnet (6) becomes O while the electron flux makes seven revolutions. has been done.

The electron flux introduced into the equilibrium orbit (3) generates synchrotron radiation and loses kinetic energy due to the braking received by the six bending electromagnets D) included in the storage lymph (10). . The high frequency wave 9 (7) is provided to compensate for this kinetic energy loss. That is, the electron flux obtains kinetic energy from the accelerating electric field generated within the radio frequency cavity (7) and is maintained on the equilibrium orbit (3).

Note that the path for the electron flux consists of a vacuum container in the front rudder that is kept in a vacuum, but it is omitted in FIG. 3.

The inflector (2) and bump electromagnet (6) are usually installed within a vacuum container.

[Problem that the invention seeks to solve]

The conventional charged particle device as described above requires a linear free space in the equilibrium orbit in which to install an inflector, a quadrupole electromagnet, a bump electromagnet, a high-frequency cavity/cavity, and the like.

Therefore, there was a problem in that it was difficult to make the device compact.

This invention was made to eliminate the above problems, and literally eliminates the linear free space along the equilibrium trajectory.
The purpose is to obtain a charged particle device that can be made compact.

[Means for solving problems]

In the charged particle device according to the present invention, a plurality of inflectors each having a center of curvature on the side of the balanced trajectory are sequentially disposed in the introduction section that guides the charged particles to the balanced trajectory, and the balanced trajectory is a circle with no straight part. It has a shape.

[Operation] □ In the present invention, charged particles introduced via a plurality of inflectors orbit in a circular equilibrium trajectory with no linear free space.

〔Example〕

WE, [1ill, storage ring c, io)' of an embodiment of the present invention;
) to form a circular equilibrium trajectory (,?a), a first inflector (2a),
The first inflector (2b), the third inflector (,
? The CLfJ+ inflector (, 2d), the y-th inflector (, 2e), the sixth inflector (2f), and the M'l inflector (2g) are arranged in sequence in a substantially circular arc shape. Therefore, these inflectors (λ
In a) to (, 2g), the center of curvature is located on the equilibrium orbit (3a) side. Furthermore, a rectangular bump electromagnet (6a
) are arranged, and a first high frequency cavity (7a), a second high frequency cavity (7b) and a fine adjustment bump electromagnet (Ab) are arranged along the balanced trajectory (3a). (9) is the 7 points (/3) on the magnetic field boundary (/3) of the storage ring (3θ).
θ is the predetermined angle between the electron beam (1) and the tangent (9), (//) is the radius vector passing through the 7 points (/2) of the perfect circle of the magnetic field boundary (/3) Each direction is indicated. The synchrotron radiation (/lI) emitted from the 7th part of the circular balanced orbit (3a) is reflected by the y-th inflector (2d)
In this example, it is assumed that the inflector is used after passing through the gap between the inflector and the third inflector (2e).

According to the above configuration, the electron beam (1) intersects (/2
), the seventh to seventh inflectors (2a) to (2
g) and further rectangular bump electromagnet (Aa
), the cross-sectional center of the electron beam (1) gently oscillates along the circular equilibrium orbit (3a).

This vibration is caused by the angle between the electron beam (1) and the equilibrium orbit (, ?a-) at the point where the center of the electron beam (1) intersects the equilibrium orbit (3a) with a weakly focused magnetic field distribution. It is removed by the fine adjustment bump electromagnet (6b) set to 0. Thus, the center of the cross section of the electron beam (1) is the equilibrium orbit (3a)
will match.

In the conventional device, there were seven high-frequency cavities, but in this embodiment, the first high-frequency cavity (?a) and the first high-frequency cavity (?
7b) is located. Although it depends on the kinetic energy of the electron beam (1), for example, with a kinetic energy of about ZOOMθ■, the diameter of the circular equilibrium orbit (3a) is 1.
In the case of about 6 m, the synchrotron radiation loss per 7 revolutions is about II! KeV.

In order to make the quantum lifetime sufficiently long with such high radiation loss, it is necessary to increase the accelerating voltage generated in the radio frequency cavities, and it may be difficult to realize this voltage with seven radio frequency cavities. In consideration of such a case, two high frequency cavities (7a) (?b) are installed in this embodiment. Of course, there are cases where the goal can be achieved with seven pieces.

Figure 2 shows a storage ring (3θ) with the above configuration.
An example of the magnetic field distribution (2/) and the coil arrangement for forming the magnetic field distribution is shown. The horizontal axis (/S) of the coordinates with (/ri) as the origin is the radial direction (//) in FIG. The vertical axis (/6) indicates the relative arrangement dimensions in the case of coil arrangement, and the relative magnetic field strength is shown for M/magnetic field distribution (2/).

The position of the equilibrium trajectory (3a) is also shown on the horizontal axis (/j). If this equilibrium orbit (3a) is made to a predetermined size, the upper coil (/zaa) will form a coil system that forms a magnetic field.
The dimensions of the lower coil (/, rb), underground coil (/9a), lower middle coil (/9b), upper small coil (20a), and lower small coil (:zob) are also relatively proportional. It's a good idea if you think about it.

As can be seen from FIG. 2, the magnetic field for the storage ring (30) is based on an air-core coil system, but it is also possible to use a superconducting coil or a normal conducting coil.

The magnetic field boundary (/3) shown in Figure 1 is shown in Figure 2, but there is a positive magnetic field part inside the magnetic field boundary (/3), especially near the equilibrium orbit (3&). In this case, a well-known weak convergence magnetic field, for example, θq to θj with an n index, is formed and plays an equivalent role to the quadrupole electromagnet (H0) in the conventional device shown in FIG.

Regarding the path of the electron beam (1) in the negative magnetic field part outside the magnetic field boundary (/3), an appropriately selected magnetic shield (not shown) is installed to reduce the magnetic field to a negligible level. be created.

The first to seventh inflectors (2a) to (2g) are
Unlike the conventional one shown in the figure, the center of curvature is located on the circular equilibrium orbit (3a) side, making it almost arc-shaped.

In the case of Figure 1, inflectors (2a) to (2g) are FU
A, the direction of the center of curvature is determined by the direction of the magnetic field, but the electric fields of the inflectors (2a) to (2g) are applied in the direction where the radius of curvature of the electron beam (1) increases. , in this sense, each inflector (2a) to (2
The function of g) is the same as that of inflector (2) in FIG. In addition, the number of inflectors (2a) to (2g) depends on the magnetic field strength of the storage ring (30) and the electron beam (
1) is appropriately selected depending on the kinetic energy.

In the above embodiment, the inflector (, 2) is used to gently introduce the electron beam (1) into the equilibrium orbit (3a).
Although a) to (2g) were used, a method using a magnetic field such as a bump electromagnet (6a) can be used instead of an inflector that uses an electric field, and the number of inflectors is not limited to seven. . Similarly, an inflector that uses an electric field instead of a bump electromagnet (Aa) can also be used.

In addition, we have explained an example in which the magnetic field of the storage ring is formed by an air-core coil, but as is well-known, the equilibrium orbit (3a)
A similar magnetic field in the vicinity can also be formed by an iron-core electromagnet, and the present invention is not limited to an air-core coil system.

Furthermore, as is well known, the synchrotron function and storage ring function can also be provided to this storage ring, but in this case, the kinetic energy of the incident electron beam can be much lower than the stored energy. The purpose can be achieved with a small number of inflectors.

〔Effect of the invention〕

As is clear from the above description, this invention is achieved by sequentially arranging a plurality of inflectors each having a center of curvature on the side of the balanced trajectory in the introduction section that guides the charged particles to the balanced trajectory. Since it is possible to form a circular balanced trajectory without any parts, there is an effect that the device can be made more compact.

In addition, the X-ray IJ wg 2 noi at the Zhao LSI factory is
It also has the effect of increasing the amount of urethane processed within the current scale of the building.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of the main parts of an embodiment of the present invention, FIG. 2 is a diagram showing the arrangement of an air-core coil system and magnetic field strength distribution in the embodiment, and FIG. 3 is a diagram showing the main parts of a conventional charged particle device. FIG. (1)...Electron beam (charged particle beam), (2a)~
(,2g)...first to seventh inflectors, (3a)
...Equilibrium orbit. In each figure, the same reference numerals indicate the same or corresponding parts. City 1 figure 1° electricity + beam

Claims (2)

[Claims] (1) A plurality of inflectors each having a center of curvature on the side of the equilibrium orbit are provided in sequence at the introduction portion of the charged particle into the equilibrium orbit around which the charged particle circulates, and has a weakly convergent magnetic field distribution; A charged particle device formed by forming the above-mentioned equilibrium orbit in the shape. (2) The charged particle device according to claim 1, comprising a plurality of high frequency cavities arranged in a balanced orbit.