JPH07263194A - Accelerator - Google Patents

Abstract

PURPOSE:To provide an accelerator with high performance for using in VLSI hyper fine working, especially having an ion cleaning electrode capable of mounting to a vacuum duct of a deflecting electromagnet. CONSTITUTION:Insulating coating 11 is applied onto the inner surface of each of vacuum ducts 3a, 3b divided into two parts up and down, copper coating 12 is applied thereon, and the copper coating and a vacuum sealed current introduction terminal are connected with a lead wire 13. Then, the vacuum ducts 3a, 3b divided into two parts are welded to form an ion cleaning electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accelerator used in, for example, ultra-LSI microfabrication, and more particularly to an accelerator having an improved ion clearing electrode.

[0002]

2. Description of the Related Art An accelerator is for accelerating a beam of electrons, protons, ions, etc. to a high energy state of about 1 billion electron volts (1 GeV). One example of this accelerator has been used in the field of elementary particle research. Large ones, for example 1km in diameter
The above has been constructed. Recently, relatively small accelerators having a diameter of about 10 m, for example, have been constructed for applications in new fields such as VLSI microfabrication (lithography) using radiation from electrons (so-called SOR light).

FIG. 3 is a top view showing a schematic structure of a conventional electron accelerator. That is, it produces electrons to some extent (Equation 10
The linear accelerator (1) that accelerates to an energy of several hundred MeV), the transport tube (2) that guides the electron beam emitted from this linear accelerator (1) to the vacuum duct (3) described later, and the electron beam collides with the residual gas. The vacuum duct (3) is placed in an ultra-high vacuum state to prevent the loss of energy, and the magnetic field in the predetermined direction (the direction from the front to the back of the paper in the drawing) to bend the electron beam in the predetermined direction (clockwise in the drawing). (4) for applying a magnetic field), a radiation port (5) for extracting radiation emitted in the tangential direction of a circle drawn by the curved beam, a quadrupole electromagnet (6a) for focusing an electron beam, and an electron. A quadrupole electromagnet (6b) for beam divergence, a high frequency resonance cavity (7) for accelerating the beam incident from the linear accelerator (1) to high energy (about GeV), and an ultrahigh vacuum in the vacuum duct (3). Status And a vacuum pump (8), and an ion clearing electrode (9) described below.

By the way, although the vacuum duct (3) is kept in an ultra-high vacuum, the electron beam still collides with the residual gas to produce a considerable amount of ions. When a large number of ions are accumulated on the orbit through which the electron beam passes, there are problems that the electron beam collides with the ions and the beam life becomes short, or the beam movement becomes unstable and causes beam loss. . To avoid this, an ion clearing electrode (9) is provided.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, in which the ion clearing electrode (9) is attached to the vacuum duct (3). The ion clearing electrode (9) is composed of two upper and lower current introducing terminals (9a) and two electrodes (9b) attached to the current introducing terminals (9a). The length in the depth direction of the electrode (9b) varies, but is usually about 20 to 30 cm. The current introducing terminal (9a) is a vacuum sealed type for holding a vacuum. + V volt (0 volt is the vacuum duct (3)) is applied to the upper current introducing terminal (9a) from a power source (not shown), and -V volt is applied to the lower current introducing terminal (9a) from a power source (not shown). When applied, a voltage of 2 V is applied between the upper and lower electrodes (9b), and the ions are displaced by this electric field (this is called ion clearing). It should be noted that the vacuum duct (3) where the ion clearing electrode (9) is located is a little larger in order to secure a vertical gap through which the beam passes.

FIG. 5 is a sectional view taken along line VV of FIG. 3, in which the deflection electromagnet (4) has a magnetic pole (4a), a yoke (4b) forming a magnetic circuit through which the magnetic lines of force pass, and an exciting coil (4) for generating a magnetomotive force. Four
c) and the like. In the case of FIG. 5, the direction of the magnetic field between the magnetic poles is such that the upper magnetic pole (4a) is the N pole and the lower magnetic pole (4a).
a) is the south pole. The electron beam is a vacuum duct (3).
It moves in the direction perpendicular to the paper surface (direction from the back surface to the front surface). (5) is a synchrotron radiation port. It is desirable that the space between the magnetic poles (4a) be as small as possible in order to miniaturize the deflection electromagnet (4).
There is almost no gap between a).

[0007]

As described above, the ion clearing electrode (9) is provided at several places on the circumference of the vacuum duct (3), but the vacuum duct (4) covered with the deflection electromagnet (4) ( 3) It is not attached to the part. This is because, as shown in FIG. 5, it is necessary to make the magnetic pole interval of the bending electromagnet (4) as small as possible, and there is no space for installing the ion clearing electrode (9). The deflection electromagnet (4) occupies a large portion of the entire circumference, and if an ion clearing electrode (9) is attached to the vacuum duct (3) of the deflection electromagnet (4), the performance as an accelerator can be improved, but in space. It cannot be installed due to restrictions. Therefore, the present invention relates to the vacuum duct (3) of the bending electromagnet (4).
We propose an ion-clearing electrode that can be attached to a high-performance accelerator, and aim to provide a high-performance accelerator.

[0008]

In order to achieve the above object, an insulating coating of ceramics or the like is provided on the upper and lower sides of the inside of the vacuum vessel (3) of the deflection electromagnet (4), and the upper and lower sides are coated with copper on the insulating coating. Forming electrodes.

[0009]

The ion-clearing action can be provided by applying a voltage of + V volt or -V volt to this copper-coated electrode. Since the thickness of the insulating coating and the copper coating may be thin, it does not hinder the movement of the beam, and it is not necessary to enlarge the vacuum duct (3). Therefore, naturally, it is not necessary to increase the magnetic pole interval of the deflection electromagnet (4).

[0010]

【Example】

(Structure of Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a main part of the embodiment, that is, a vacuum duct (3) of a bending electromagnet (4). The vacuum duct (3) consists of an upper duct (3a) and a lower duct (3b). Upper duct (3a),
The inner surface of the lower duct (3b) is provided with a ceramic insulating coating (11) by ceramic spraying or the like.
The vacuum duct (3) is used in ultra-high vacuum and 200 ℃
It is suitable to use ceramics, etc., which emit little gas and have high heat resistance because they are baked to a certain degree. A copper coating (12) is formed on the insulating coating (11) by vapor deposition, sputtering or the like. The copper coating (12) is connected to the current introducing terminal (9a) by the lead wire (13). The current introducing terminal (9a) may be the same as that shown in FIG. 4, and is of a vacuum sealed type. Thus, the upper duct (3
a), after forming the lower duct (3b), weld them together,
The vacuum duct (3) is used.

(Operation of the embodiment) When + V volt is applied to the upper current introducing terminal (9a) in FIG. 1 from a power source (not shown) and -V volt is applied to the lower current introducing terminal (9a) from a power source (not shown), A voltage of 2V is applied between the copper coatings (12) to perform ion clearing.

(Effect of Embodiment) As described above, since the ions can be removed from the orbit by the ion clearing action even in the vacuum duct (3) of the deflecting electromagnet (4), the electron beam can be stably rotated. Also, since the insulating coating and the copper coating forming the ion clearing electrode are thin, it is not necessary to increase the size of the vacuum duct (3), and thus the deflection electromagnet (4).

(Other Embodiment) Next, another embodiment is shown in FIG. FIG. 2 is a sectional view of the same portion as FIG. 1, showing an example in which an insulating coating (11) and a copper coating (12) are formed on only one side. In the example of FIG. 2, the lower current introducing terminal (9a)
When a voltage of -V volt is applied to the vacuum vessel (3), the voltage of V volt is applied to the electron beam because the vacuum container (3) has 0 volt, and ion clearing is performed. This example can be adopted when the ion clearing voltage may be low. In addition,
Although the above description is intended for the deflection electromagnet (4) part, it is obvious that the same ion clearing electrode shape can be adopted even for the electromagnet part having the same shape as the deflection electromagnet such as the correction electromagnet. Is.

[0014]

According to the present invention described above, the ion clearing electrode can be attached to the vacuum duct of the deflection electromagnet section without increasing the size of the deflection electromagnet.
Ions on the electron beam orbit of the deflection electromagnet can be removed. Therefore, it is possible to provide a high-performance accelerator with the same dimensions as the conventional one, because it is difficult for the ions to shorten the beam life and beam loss.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an ion clearing electrode of the present invention.

FIG. 2 is a sectional view similar to FIG. 1, showing another embodiment of the present invention.

FIG. 3 is a top view showing a schematic configuration of a conventional accelerator.

FIG. 4 is an IV of FIG. 3 showing a conventional ion clearing electrode.
-A sectional view taken along the line IV.

5 is a sectional view taken along the line VV of FIG. 3 showing the arrangement of a conventional bending electromagnet and a vacuum duct.

[Explanation of symbols]

3 ... Vacuum duct 3a ... Upper duct 3b ... Lower duct 4 ... Bending electromagnet 5 ... Radiant light port 9 ... Ion clearing electrode 9a ... Current introducing terminal 9b ... Electrode 11 ... Insulation coating 12 ... Copper coating 13 ... Lead wire

Claims (2)

[Claims] 1. A vacuum-sealing type electric current provided on an inner surface of each of the upper and lower divided vacuum ducts with an insulating coating, with a copper coating on the inner surface, and with the copper coating and the divided into two divided vacuum ducts. An accelerator characterized in that an ion clearing electrode is formed by connecting lead terminals between lead-in terminals and then welding two divided vacuum ducts. 2. A vacuum-sealed type in which an insulating coating is applied to the inner surface of only one of the upper and lower divided vacuum ducts, a copper coating is applied thereon, and the copper coating and the divided vacuum ducts are respectively provided. An accelerator characterized in that an ion clearing electrode is formed by connecting a lead wire between current introduction terminals and then welding the other vacuum duct without coating.