JPH0669000A - Radiation absorber of particle accelerator vacuum chamber - Google Patents

Abstract

PURPOSE:To improve thermal conductivity of a welding part and eliminate the possibility that a radiation absorber is removed from a vacuum chamber. CONSTITUTION:The radiation light absorber of a particle accelerator vacuum chamber is provided on the inner wall 22a of a vacuum chamber 22 to absorb radiation 25 generated from particles passing inside the vacuum chamber 22 and formed by means of build up welding and a cooling water passage part 26 through the inside of which cooling water passes is provided on the wall part of the vacuum chamber 22 adjacent to the radiation absorber 21. Thus, the radiation absorber is firmly fixed in its condition of close contact with the predetermined position of the inside wall of the vacuum chamber and effectively cooled by the cooling water passage part 26. Since the radiation absorber itself includes no pressure boundary, it is not subjected to thermal fatigue and can be miniaturized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation absorber for a particle accelerator vacuum chamber such as a synchrotron.

[0002]

2. Description of the Related Art In recent years, in various fields such as manufacturing of VLSI, diagnosis in the medical field, molecular analysis, structural analysis, etc., synchrotron radiation (Synchrotron Radial Ratio)
n) The SOR lithography technique using light (abbreviated as SOR light) is considered promising. This SOR light impinges on an electron beam accelerated to near the speed of light by a linear accelerator (linac) into a storage ring, and deflects the electron beam while accelerating the electron beam while giving energy to the electron beam. It is generated when deflected by an electromagnet, and has excellent features such as high beam output, strong directivity and high brightness. Then, in the semiconductor industry such as VLSI, the generated SOR light is sent to a semiconductor fine processing apparatus such as an exposure apparatus through a beam channel and used as a light source for fine processing of VLSI. The storage ring is formed by sequentially connecting aluminum vacuum chambers with a flange to form a ring shape. A beam chamber 1 having an elliptical cross section and a getter pump chamber having a substantially rectangular cross section as shown in FIG. 2 and beam chamber 1
A two-chamber type vacuum chamber 4 composed of a slit 3 communicating with the getter pump chamber 2 is preferably used.

In the storage ring, there are parts such as a bellows, a gate valve, and a ceramic chamber that cannot be provided with a cooling function. Since the SOR light is not applied to these parts, the inner wall of the beam chamber 1 on the SOR light incident side is provided. SO adjacent to the cooling water pipe (cooling water passage part) 5 of 1a
An absorber (radiant light absorber) 6 that absorbs R light is installed. FIG. 4 shows another example of the absorber, in which the absorber 8 is welded to a predetermined position of the inner wall 7a of the vacuum chamber 7 and the cooling water pipe 9 is provided on the inner wall 7a. Further, as another example of the absorber, as shown in FIG. 5, a hole 10 for attaching the absorber is formed in the inner wall 7a of the vacuum chamber 7, and the absorber 12 provided with the cooling water pipe 11 is welded to the hole 10. Some have been done.

[0004]

However, since the conventional absorbers 6 and 8 are fixed by welding, there is a drawback that the thermal conductivity of the welded portion is lowered.
Further, there is a drawback that the absorbers 6 and 8 that absorb the SOR light and are melted by the heat may be missing from the beam chamber 1 and the vacuum chamber 7. Further, in the absorber 12, since the absorber 12 is welded to the hole 10, there is a pressure boundary between the atmosphere and the vacuum, and S
There is a problem that a thermal cycle of temperature increase / decrease depending on the presence or absence of OR light irradiation is applied to this pressure boundary to cause thermal fatigue. Also,
Since the cooling water pipe 11 is provided inside the absorber 12, there is a problem that the absorber 12 becomes large.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a synchrotron radiation absorber for a particle accelerator vacuum chamber which can solve the conventional drawbacks and problems.

[0006]

In order to solve the above-mentioned problems, the present invention employs the following radiation absorber of a particle accelerator vacuum chamber. That is, a radiant light absorber of a particle accelerator vacuum chamber provided on the inner wall of the vacuum chamber and absorbing radiant light generated by particles passing through the vacuum chamber, the radiant light absorber being formed by overlay welding. In addition, a cooling water passage portion through which cooling water passes is provided in a wall portion of the vacuum chamber adjacent to the radiant light absorber.

[0007]

In the radiant light absorber of the particle accelerator vacuum chamber of the present invention, the radiant light absorber is firmly fixed to the inner wall of the vacuum chamber by overlay welding. Further, the cooling water passage portion effectively cools the radiant light absorber. As a result, the thermal conductivity of the welded portion is improved as compared with the conventional radiation absorption body, and therefore, a sufficient cooling effect is obtained, and the radiation absorption body is not likely to drop from the vacuum chamber. Also, because there is no pressure boundary, there is no worry of thermal fatigue,
It can be downsized.

[0008]

1 is a vertical sectional view showing an embodiment of an absorber (radiation light absorber) of a synchrotron (particle accelerator) vacuum chamber of the present invention, and FIG. 2 is a line AA of FIG. FIG. The absorber 21 includes a ceramic chamber 24 fixed between the vacuum chambers 22 and 22 by aluminum plates 23 and 23.
In order to protect from 5, the inner wall 22 of the vacuum chamber 22
It is formed by carrying out machining after overlay welding on a. A cooling water pipe (cooling water passage portion) 2 is provided on the wall of the vacuum chamber 22 adjacent to the absorber 21.
6 is provided.

The absorber 21 is firmly fixed in a state of being in close contact with the inner wall 22a of the vacuum chamber 22 by overlay welding. Further, the absorber 21 is effectively cooled by the cooling water pipe 26. As a result, the thermal conductivity of the welded portion is improved as compared with the conventional absorbers 6, 8 and 12, and therefore a sufficient cooling effect is obtained.

According to the absorber 21 of this embodiment, the vacuum chamber 2 is formed by overlay welding on the inner wall 22a of the vacuum chamber 22 and is adjacent to the absorber 21.
Since the cooling water pipe 26 is provided in the second wall portion, the cooling water pipe 26 can be firmly fixed to the inner wall 22a of the vacuum chamber 22 in a close contact with a predetermined position, and the cooling water pipe 26 can effectively cool. it can. Therefore, the thermal conductivity of the welded portion can be improved as compared with the conventional absorbers 6, 8 and 12, and there is no fear that the absorber 21 will be missing from the vacuum chamber 22. Further, since there is no pressure boundary, there is no fear of thermal fatigue and miniaturization is possible.

[0011]

As described above, according to the radiant light absorber of the particle accelerator vacuum chamber of the present invention, the radiant light generated by the particles provided on the inner wall of the vacuum chamber and passing through the vacuum chamber is absorbed. Radiation absorber of a particle accelerator vacuum chamber, wherein the radiation absorber is formed by overlay welding, and cooling water is internally passed through a wall of the vacuum chamber adjacent to the radiation absorber. Since the cooling water passage portion is provided, it can be firmly fixed to the predetermined position of the inner wall of the vacuum chamber in a close contact state, and cooling can be effectively performed by the cooling water passage portion.
Therefore, it is possible to improve the thermal conductivity of the welded portion as compared with the conventional synchrotron radiation absorber, and there is no fear that the radiant light absorber will be missing from the vacuum chamber. Further, since there is no pressure boundary, there is no fear of thermal fatigue and miniaturization is possible.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an absorber of a particle accelerator vacuum chamber of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view showing a vacuum chamber of a conventional particle accelerator.

FIG. 4 is a vertical sectional view showing an absorber of a conventional particle accelerator vacuum chamber.

FIG. 5 is a vertical sectional view showing an absorber of a conventional particle accelerator vacuum chamber.

[Explanation of symbols]

 21 Absorber (Radiation Absorber) 22 Vacuum Chamber 22a Inner Wall 24 Ceramic Chamber 25 SOR Light 26 Cooling Water Pipe (Cooling Water Channel)

Claims (1)

[Claims] 1. A radiant light absorber of a particle accelerator vacuum chamber, which is provided on an inner wall of a vacuum chamber and absorbs radiant light generated by particles passing through the vacuum chamber, wherein the radiant light absorber is built up. A radiant light absorber for a particle accelerator vacuum chamber, characterized in that a cooling water passage portion, through which cooling water is passed, is provided in a wall portion of the vacuum chamber formed by welding and adjacent to the radiant light absorber.