JPH0495396A - Synchrotron radiation absorber - Google Patents

Abstract

PURPOSE:To facilitate maintenance without enlarging a size of a vacuum chamber by transmitting unnecessary radiation light generated frown an electron beam inside the vacuum chamber through a light transmitting portion provided in the vacuum chamber, and shieldingly absorbing it by a cooling plate disposed inside an absorber chamber formed outside the transmitting portion. CONSTITUTION:A light transmitting portion 3 for transmitting radiation light 2 is provided in a portion of a vacuums chamber 1 where unnecessary radiation light 2 is generated. Outside the vacuum chamber 1 partitioned by the light transmitting portion 3, an absorber chamber 4 kept in a vacuum state is formed. Inside the absorber chamber 4, there is provided a cooling plate 5 for absorbing the radiation light 2 transmitted through the light transmitting portion 3. The unnecessary radiation light 2 generated from an electron beam inside the vacuum chamber 1 is transmitted through the light transmitting portion 3 to be shieldingly absorbed by the cooling plate 5 inside the absorber chamber 4.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is directed to the use of unnecessary synchrotron radiation (S) generated from an electron beam in a vacuum chamber in an accelerator such as a synchrotron.
This invention relates to an SR absorber for absorbing radio waves.

[Prior Art] In an accelerator such as a synchrotron, when an electron beam in a vacuum chamber curves at the path light velocity, synchrotron radiation is generated in the tangential direction of the electron beam.
on) occurs. This radiation irradiates the inner wall of the vacuum chamber, causing it to generate heat. Therefore, in order to absorb such unnecessary radiation, the present applicant has previously developed an SR absorber a as shown in FIG.

As shown in the figure, a cooling plate d is provided in the vacuum chamber b to block and absorb unnecessary radiation C. This cooling plate d is placed in an absorber chamber e that is formed integrally with the chamber b by enlarging a part of the vacuum chamber b, and is used to cool an electron beam (not shown) passing through the vacuum chamber b. It is designed not to interfere with the orbit. The cooling plate d absorbs the radiation C and generates heat, so that the inside thereof is cooled by cooling water.

This SR absorber a absorbs the unnecessary radiation C by blocking it with a cooling plate d in the vacuum chamber b.

[Problems to be Solved by the Invention] By the way, when the cooling plate d is irradiated with the synchrotron radiation C, gas is ejected from the cooling plate d. Since the cooling plate d is provided in the vacuum chamber b, this gas diffuses into the inner metal area of the vacuum chamber b and deteriorates the degree of vacuum in the chamber b. It is necessary to mold the material using an expensive ultra-high vacuum material (for example, high-purity oxygen-free copper, etc.).

Furthermore, in the event that the cooling water inside the cooling plate d leaks, the leaked cooling water instantly evaporates and spreads over the entire area of the vacuum chamber b, causing damage to the entire area of the vacuum chamber b.

In addition, when performing maintenance on the cooling plate d, it is necessary to perform maintenance under ultra-high vacuum conditions (approx.
The cooling plate d must be taken out from the vacuum chamber b after the metal body in the vacuum chamber b of r) is brought to atmospheric pressure, and this work is complicated.

In addition, this cooling plate d is placed in an enlarged diameter chamber e formed integrally with a part of the vacuum chamber b by expanding a part of the vacuum chamber b so as not to obstruct the trajectory of the electron beam passing through the vacuum chamber b. Therefore, the space of the vacuum chamber b increases by the enlarged diameter chamber e, and the degree of vacuum of the vacuum chamber b deteriorates.

The purpose of the present invention, which was created in consideration of the above circumstances, is to provide an SR absorber that does not require an increase in the space of the vacuum chamber, that the vacuum chamber is not affected by the gas generated from the cooling plate, and that is easy to maintain. It is something.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides an SR that absorbs unnecessary synchrotron radiation generated from an electron beam in a vacuum chamber.
In the absorber, a light transmitting part for transmitting the synchrotron radiation is provided at a portion of the vacuum chamber where unnecessary radiation is generated, and an absorber chamber kept in a vacuum is formed outside the absorber chamber, and the light is transmitted inside the absorber chamber. It is constructed by providing a cooling plate that blocks and absorbs the radiation that has passed through the transmission section.

U action] Unnecessary radiation generated from the electron beam in the vacuum chamber is transmitted through a light transmitting part provided in the vacuum chamber, and is blocked and absorbed by a cooling plate in an absorber chamber formed outside of the light transmitting part. .

At this time, gas is generated from the cooling plate in the absorber chamber, but since the cooling plate is provided outside the vacuum chamber, the degree of vacuum in the vacuum chamber is not affected by the gas.

Moreover, the space of the vacuum chamber does not become large by providing the cooling plate.

Furthermore, the cooling plate can be maintained from the absorber chamber side without affecting the vacuum degree of the vacuum chamber.

[Example] An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a partial sectional view showing a part of a vacuum chamber 1 of a synchrotron. This vacuum chamber 1 is a chamber 1
In order to prolong the lifetime of the electron beam (not shown) passing through the chamber, the
0-” Torr).The vacuum chamber 1
When an electron beam passing through the center at the speed of light curves,
Unnecessary radiation 2 is generated in the tangential direction 1 As shown in the figure, a vacuum chamber 1 in which this unnecessary radiation 2 is generated
A light transmitting section 3 that transmits the radiation light 2 is provided at a location.

This light transmitting portion 3 is formed so that the wall thickness of the vacuum chamber 1 at that portion is thinner than other portions so that the emitted light 2 can easily pass therethrough. An absorber chamber 4 maintained in a vacuum state is formed outside the vacuum chamber 1 partitioned by the light transmitting section 3. Inside this absorber chamber 4,
Cooling plate 5 that absorbs the radiation light 2 that has passed through the light transmitting section 3
is provided.

The cooling plate 5 is made of a Cu plate with good thermal conductivity.
Its interior is cooled by cooling water. That is, the cooling water that has flowed into the cooling plate 5 from the cooling water inlet 5a passes through the cooling water passage inside the cooling plate 5 and emits the radiation light 2.
The cooling plate 5, which has generated heat due to the irradiation, is cooled, and the cooling water flows out from the cooling water outlet portion 5b.

Furthermore, an exhaust pump (not shown) is connected to the absorber chamber 4 for evacuating the inside of the absorber chamber 4 . Since the electron beam does not pass through the absorber chamber 4, the degree of vacuum in the absorber chamber 4 has nothing to do with the lifespan of the electron beam, and there is no need to create an ultra-high vacuum state like in the vacuum chamber 1. Low vacuum is sufficient.

As shown in FIG. 2, the SR absorber A having such a configuration can be vertically divided into an upper absorber chamber 4a and a lower absorber chamber 4b.

The operation of this embodiment having the above configuration will be described.

Unnecessary radiation 2 generated from the electron beam in the vacuum chamber 1 is transmitted through a light transmitting section 3 provided in the vacuum chamber 1, and then passes through a cooling plate 5 in an absorber chamber 4 formed outside the light transmitting section 3.
It is blocked and absorbed by

At this time, gas will be ejected from the cooling plate 5, but since the cooling plate 5 is partitioned off by the light transmitting section 3 and is provided outside the vacuum chamber 1, this gas will not flow into the vacuum chamber 1. Do not invade.

That is, the gas ejected from the cooling plate 5 fills only the absorber chamber 4 without affecting the vacuum degree of the vacuum chamber 1. Therefore, the material of the cooling plate 5 may be a material that generates a large amount of gas as long as it absorbs the radiation 2, and an inexpensive material can be selected. In addition,
The gas filling the absorber chamber 4 is efficiently removed by evacuating the absorber chamber 4.

Further, since the cooling plate 5 is partitioned by the light transmitting part 3 and provided outside the vacuum chamber 1, the space of the vacuum chamber 1 does not become large. The efficiency can be increased to the same level as when this SR absorber A is not provided.

In addition, when disassembling and maintaining the cooling plate 5, leave the degree of vacuum in the vacuum chamber 1 as it is and bring only the inside of the absorber chamber 4 to atmospheric pressure, and then divide the absorber chamber 4 into upper and lower halves as shown in Fig. 2. , cooling plate 5 from inside the absorber chamber 4
All you have to do is take it out.

That is, when the cooling plate 5 is disassembled and maintained, the SR absorber A is replaced with the SR absorber a shown in FIG.
It is not necessary to bring the entire vacuum chamber b to atmospheric pressure as in the above, and maintenance becomes easy.

Furthermore, even if the cooling water inside the cooling plate 5 leaks, the leaked cooling water will only fill the absorber chamber 4, and the damage will not spread to the entire vacuum chamber 1.

Furthermore, the synchrotron radiation 2 that has passed through the light transmitting section 3 will radioactiveize the atmosphere on the path of the synchrotron radiation 2 until it is absorbed by the cooling plate 5, but this path portion is covered by the absorber chamber 4. Since it is divided into sections and is in a low vacuum state, atmospheric activation is not a problem.

By the way, the light transmitting section 3 provided in the vacuum chamber 1
Since the wall thickness of the vacuum chamber 1 in that part is thinner than in other parts, its mechanical strength becomes weak. However, if we focus on the pressure difference between the inside and outside of the vacuum chamber 1 which is partitioned by the light transmitting part 3, we can see that just as the inside of the vacuum chamber 1 is in a vacuum state (ultra-high vacuum state), the inside of the absorber chamber 4 outside the vacuum chamber 1 is also in a vacuum state (ultra-high vacuum state). Since it is in a vacuum state (low vacuum state), the pressure applied to the light transmitting section 3 due to these pressure differences is extremely small, and the light transmitting section 3 will not be damaged due to this pressure difference. In this embodiment, the light transmitting section 3 provided in the vacuum chamber 1 is formed to be thinner than the wall thickness of the vacuum chamber 1 at that part or other parts so that the emitted light can easily pass through. However, the invention is not limited to this, and the part of the vacuum chamber 1 where the light transmitting part 3 is provided may be formed of a light metal such as beryllium through which synchrotron radiation can easily pass through.4U Effects of the Invention As explained above, According to the present invention, the following excellent effects can be exhibited.

(1) Unnecessary radiation generated from the electron beam inside the vacuum chamber can be absorbed.

(2) The vacuum degree of the vacuum chamber can be increased without increasing the space of the vacuum chamber.

(3) Gas ejected from the cooling plate does not enter the vacuum chamber, and the degree of vacuum in the vacuum chamber can be increased.

(4) Without affecting the vacuum degree of the vacuum chamber,
The cooling plate can be maintained from the absorber chamber side, making maintenance of the cooling plate easy.

(5) When the synchrotron radiation transmitted through the light transmitting part is emitted into the atmosphere, it will radioactivate the atmosphere, but since it is divided by the absorber chamber and is in a low vacuum state, the atmosphere will not be activated. Not a problem.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of essential parts of an SR absorber showing an embodiment of the present invention, Fig. 2 is an exploded perspective view of the SR absorber shown in Fig. 1, and Fig. 3 is an SR absorber developed earlier by the applicant. FIG. In the figure, 1 is a vacuum chamber, 2 is unnecessary radiation, 3 is a light transmitting section, 4 is an absorber chamber, and 5 is a cooling plate. Nobuo (1 other person) a 5”i” EP version 2nd figure

Claims (1)

[Claims] 1. In an SR absorber that absorbs unnecessary radiation generated from an electron beam in a vacuum chamber, a light transmitting portion that transmits radiation is provided in a portion of the vacuum chamber where unnecessary radiation is generated, and An SR absorber characterized in that an absorber chamber maintained in a vacuum is formed outside the SR absorber, and a cooling plate is provided inside the absorber chamber to block and absorb radiation light transmitted through the light transmitting portion.