JPH02199800A - Radiated light absorber - Google Patents

Abstract

PURPOSE:To prevent the temperature increase of a beam duct by providing two emitted light absorbers in such a manner that the respective concave parts face to each other with a beam orbit between them, and reflecting and attenuating an emitted light by the both concave parts. CONSTITUTION:Radiated light absorbers 2, 3, are curved so that they can be provided along the deflection of a beam duct 1, and concave parts 2s, 3s having a semi-circular sectional form are formed on one surface of each absorber in such a manner that the both concave parts 2s, 3s face to each other with a beam orbit Q between them and the focus of the concave parts 2s, 3s accords with the beam orbit Q. A cooling channel 4 having a cooling liquid nitrogen passed through its inner part is provided on a determined part of the opposite surface of each concave part 2s, 3s of the emitted light absorbers 2, 3. Thus, an emitted light is absorbed and attenuated while it is reflected between the both concave parts 2s, 3s. In this case, although the temperature of the emitted light absorbers 2, 3 is increased, the heat is released to the duct outside by the cooling channel 4, and the heating of the beam duct 1 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a synchrotron radiation absorber provided in a duct of a particle accelerator in order to prevent heat generation due to radiation of synchrotron radiation.

[Prior Art] When a particle beam circulating in a vacuum duct of a particle accelerator is deflected by a magnetic field of a deflecting electromagnet, synchrotron radiation ranging from infrared to X-ray is emitted in a tangential direction from the beam trajectory. Since this synchrotron radiation is extremely powerful and has good directivity, it has high utility value in industrial applications such as printing fine patterns on integrated circuits. A part of the generated synchrotron radiation is guided to the outside of the duct via the synchrotron radiation extraction tube for the above-mentioned purpose, while the other radiation is irradiated onto the wall of the beam duct to raise the temperature of the duct. let

[Problem to be Solved by the Invention] In order to prevent the temperature rise of the beam duct due to the irradiation of such synchrotron radiation, for example, in the synchrotron device disclosed in Japanese Patent Application Laid-Open No. 63124400, the radiation A light absorber 20 is provided. This absorber 2 () is provided along the wall surface on the outer diameter side of the deflection part of a beam duct (not shown), and 21 indicates the trajectory (hereinafter referred to as beam trajectory Q) of the particle beam orbiting inside the beam duct. ) is a synchrotron radiation extraction tube for extracting synchrotron radiation X emitted in the tangential direction to the outside of the duct. Further, the interior of the absorber 20 is filled with liquid nitrogen or the like, and as the synchrotron radiation is absorbed by the absorption surface 20b of the absorber 20, the absorber 20, whose temperature increases, is cooled by the liquid nitrogen. There is.

However, since the absorption surface 20b of the absorber 20 is formed in a plane perpendicular to the orbital plane of the beam trajectory Q,
A part of the radiation light irradiated to this absorption surface 20b is reflected,
When the reflected light hits the wall of the beam duct, the temperature of the duct may rise, and if the beam duct is kept at the temperature of liquid helium, this poses a problem (increasing helium consumption).

The present invention has been made to eliminate the above-mentioned problems, and an object of the present invention is to provide a synchrotron radiation absorber that can prevent heating of a beam duct due to radiation light reflected by the synchrotron radiation absorber.

[Means for Solving the Problems] A synchrotron radiation absorber of the present invention is a synchrotron radiation absorber provided inside a beam duct of a synchrotron radiation device, and is composed of two synchrotron radiation absorbers each having a concave cross section. The synchrotron radiation absorber is characterized in that the concave portions of the synchrotron radiation absorbers are opposed to each other on the plane defined by the beam trajectory, with the beam trajectory sandwiched therebetween.

[Function] According to the above configuration, a part of the synchrotron radiation generated by the deflection of the particle beam is absorbed by the concave surface of one of the synchrotron radiation absorbers, but the other synchrotron radiation is reflected by the concave surface. toward the concave portion of the other synchrotron radiation absorber. In this way, the emitted light is attenuated while being mutually reflected by both concave surfaces, so that the beam duct is not irradiated with the emitted light, so no temperature rise occurs.

[Embodiment] FIG. 1 shows an embodiment of the synchrotron radiation absorber of the present invention.

l indicates the cross section of the beam duct. 2 and 3 are
This is a synchrotron radiation absorber made of a metal plate with good thermal conductivity, located on one plane formed by the beam trajectory Q (in the horizontal direction of the beam trajectory Q in the figure). The radiation light absorber 2. is curved so as to be provided along the deflection section of the duct 1, and , 3 have concave portions 2s, 3s each having a semicircular cross-sectional shape.
are formed, and both concave parts 2s and 3s face each other across the beam trajectory Q, and concave parts 2s and 3s
The focal point of the beam coincides with the beam trajectory Q.

Furthermore, each concave portion 2 of each radiation absorber 2.3
A cooling channel 4 through which liquid nitrogen for cooling is passed is provided in a predetermined portion of the surface opposite to s and 3 s.

In addition, the synchrotron radiation absorber 2.3 is attached to an appropriate support (not shown).
is fixed to the inner circumferential surface of the beam duct l.

In the synchrotron radiation absorber having the above configuration, one of the synchrotron radiation absorbers 3 is a beam duct! If the particle is located on the outer diameter side of do. At this time, most of the emitted radiation light is absorbed by the concave surface 3s of the synchrotron radiation absorber 3, but the rest is reflected by the concave surface 3s of the synchrotron radiation absorber 3. Beam trajectory Q
are the concave portions 2s and 3s of both synchrotron radiation absorbers 2.3.
Therefore, the synchrotron radiation reflected by the concave portion 3s of the synchrotron radiation absorber 3 passes through the beam trajectory Q and heads toward the concave portion 2s of the other synchrotron radiation absorber 2, and this concave portion 2
The synchrotron radiation reflected by s passes through the beam trajectory Q again and enters the other concave portion 3s. In this way, both concave portions 2s, 3
The emitted light is absorbed and attenuated while being reflected between s. The temperature of the radiation absorber 2.3 increases due to the absorption of the radiation, but the heat is released to the outside of the duct by the cooling channel 3.

In the above embodiment, the concave portions 2s, 3s in each synchrotron radiation absorber 2.3 are formed so that the focal point of the concave surface portions 2s, 3s approximately coincides with the beam trajectory Q. The above-mentioned effect of reflecting/attenuating the emitted light can be sufficiently obtained by simply forming the concave surface appropriately.

Furthermore, although the synchrotron radiation absorbers 2 and 3 are formed of a single metal plate, they are not limited to this shape; for example, even a duct-shaped synchrotron radiation absorber 20 shown in FIG. It is sufficient that the absorption surface 20b has a semicircular concave portion.

[Effects of the Invention] As explained above, the present invention provides two synchrotron radiation absorbers such that their respective concave portions face each other across the beam trajectory, and reflects and attenuates the synchrotron radiation on both concave portions. As a result, the beam duct is not irradiated with synchrotron radiation, and the temperature of the beam duct can be prevented from rising.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the synchrotron radiation absorber of the present invention, FIG. 2 is a perspective view of the synchrotron radiation absorber shown in FIG. 1, and FIG. 3 is a perspective view of a conventional synchrotron radiation absorber. l... Beam duct, 2.3... Synchrotron radiation absorber, 2s, 3s... Concave portion, 4... Cooling channel. Figure 1 Figure 3

Claims (2)

[Claims] (1) A synchrotron radiation absorber installed inside the beam duct of a synchrotron radiation device, which is composed of two synchrotron radiation absorbers each having a concave cross section, and the synchrotron radiation absorber is arranged on a plane defined by the beam trajectory. A synchrotron radiation absorber characterized in that the respective concave portions are opposed to each other so as to sandwich the beam trajectory. (2) The synchrotron radiation absorber according to claim 1, wherein a focal point of the concave portion of the synchrotron radiation absorber is aligned with the beam trajectory.