JP2847299B2 - Optical element holding table and holding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a holder for an optical element used for synchrotron radiation and a holding method.

[Prior Art] Generally, an optical element is installed on a drive-type holding table for adjusting an optical axis or the like. In addition, this allows cooling from the back surface of the optical element.

Conventionally, when the optical element is placed on the holding table, it is fixed by a jig as it is, or in consideration of cooling efficiency, an indium foil is inserted between the element and the holding table, so-called crimping. It was the mainstream to use the method that was used.

In addition, a method of fusing the element and the holding table with indium in consideration of cooling efficiency, that is, removing the holding table from the apparatus main body and using a hot plate or the like to melt the indium melting point (15 ° C.
(6.6 ° C.) or more, and then indium is melted and spread over the entire surface, and a heated optical element is similarly stuck thereon.

[Problems to be Solved by the Invention] However, in the method of fixing with a jig or the method of crimping, the contact area between the element and the holding table is still relatively small, so that it was difficult to obtain sufficient cooling efficiency.

In addition, the method of fusing with indium has disadvantages such as that the holding table must be removed from the apparatus main body every time, and a heating device such as a large hot plate is required.

The object of the present invention is to solve the problems of the prior art,
An optical element holding base and holding method that enables fusion with a low melting point metal such as indium without removing the holding base from the apparatus body at the time of mounting and replacing the optical element and that does not require a large-area heating device. To provide.

[Means and Actions for Solving the Problems] In order to achieve the above object, according to the present invention, a holding table for holding an optical element used for synchrotron radiation light is provided at a lower portion of a surface in contact with the optical element. A heating means such as a heater is provided by embedding or the like.

By embedding a heater or the like inside the holder, the optical element and the holder can be fused with a low-melting metal such as indium without removing the holder from the apparatus main body and without requiring a large heating device. it can. As a result, even when the optical element is irradiated with high-intensity light, the optical element is cooled through the metal of the fusion material by the cooling mechanism provided on the holding table in advance, so that the optical element is deformed or deteriorated by the absorbed heat. There is no.

The optical element in the present invention is a reflector or a diffraction grating in a beam line of an SR (synchrotron radiation) ring,
Includes an optical element to be irradiated with emitted light, such as a reflecting mirror incorporated in an apparatus utilizing emitted light, for example, an X-ray exposure machine or an X-ray microscope. In addition, the material of the holding table may be arbitrary, but a material having a high thermal conductivity is preferable in consideration of heating and cooling performance, uniformity, and the like. In order to minimize the difference in the coefficient of thermal expansion between the optical element and the holder, it is preferable to obtain the desired coefficient of thermal expansion by using the same material or an alloy containing nickel for the holder. It is desirable to select the material of the holding table in consideration of the above two points.

The shape and material of the heater inside the holding table may be arbitrarily set, but it is preferable to set the temperature of the surface of the holding table to be uniform during heating.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

Example 1 As shown in FIG. 1, using a stainless steel holding table 1 in which a sheath heater 2 capable of heating up to a maximum temperature of 300 ° C. is embedded, X of silicon carbide (SiC) having an outer size of 400 × 120 × 40 mm is used.
The line grazing incidence mirror was fused with indium (In).

For the fusion with indium, first, the surface of the holding table 1 is cleaned with isopropyl alcohol (IPA) or the like, and then the heater 2 is heated.
After the temperature of the surface 3 was raised to about 200 ° C., 35 g of granular indium was placed on the surface 3 and melted. Then, as shown in FIG. 2, the molten indium 4 is stretched so as to be substantially uniform over the entire surface using stainless steel tweezers, and then an optical element (oblique incidence mirror for X-ray) 5 is mounted thereon and fused. did. In the case of fusion, the back surface of the optical element 5 is previously heated to about 80 ° C. by a heat gun, and after being placed on the holding table 1, is left for about 15 minutes until the element surface is isothermal with the holding table. Was turned off.

The oblique incidence mirror 5 for X-rays was irradiated with synchrotron radiation having an acceleration voltage of 2.5 GeV and a storage current of 250 mA. When the surface temperature of the oblique incidence mirror 5 reached a thermal equilibrium state, the surface temperature was 20.7. ° C.

For comparison, the same X-ray reflecting mirror made of silicon carbide was placed on the same holding table, and the same synchrotron radiation was applied by making thermal contact only with the weight of the mirror.
After reaching the thermal equilibrium state, the temperature of the mirror surface was measured and found to be 28.1 ° C.

However, in both of the above experiments, the holder was water-cooled by a cooling tube embedded therein during irradiation with synchrotron radiation and kept at 20 ° C.

Example 2 An oblique incidence mirror made of copper (Cu) having an outer dimension of 400 × 120 × 40 mm for X-ray
It was fused with indium (In) to a copper holding base in which a sheath heater capable of heating up to 250 ° C was embedded. The fusing method was the same as in Example 1.

The oblique incidence mirror for X-rays was irradiated with synchrotron radiation similar to that used in Example 1, and when the thermal equilibrium state was reached, the temperature of the mirror surface was measured to be 20.3 ° C. Was.

For comparison, an identical copper X-ray incidence mirror was placed on the same holding table, and the same synchrotron radiation was irradiated by thermal contact only by the weight of the mirror itself. After reaching the thermal equilibrium state, the temperature of the mirror surface was measured to be 27.7 ° C.

However, in both tests, the holding table was kept at 20 ° C. by water cooling as in Example 1.

Also, when the amount of deformation of the mirror of the mirror fused with indium of the present embodiment and that used as a comparison was calculated from the temperature rise, the amount of deformation of the mirror in the present embodiment was about 0.1 μm. On the other hand, the deformation amount in the case of the comparative example in which nothing was interposed was 1.6 μm.

Example 3 An X-ray diffraction grating made of quartz glass (SiO ₂ ) having an outer size of 50 × 40 × 7 mm was fused with indium (In) to a holding table in which a sheath heater capable of heating up to 300 ° C. was embedded. However, invar (nickel-based alloy)
Was used to adjust the content of nickel (Ni) so that the coefficient of thermal expansion of the holder was equal to the coefficient of thermal expansion of the quartz glass constituting the diffraction grating.

The X-ray diffraction grating was irradiated with synchrotron radiation similar to that used in Example 1, and after reaching a thermal equilibrium state, the temperature of the diffraction grating surface was measured.
° C.

For comparison, the same synchrotron radiation was irradiated on the same quartz glass X-ray diffraction grating, which was only placed on the same Invar holding table. The diffraction grating surface temperature was 42.5 ° C.

However, in both tests, the holding table was kept at 20 ° C. by water cooling as in Example 1, and the diffraction grating was cooled through the holding table.

[Effects of the Invention] As described above, according to the present invention, since the heating means is provided inside the holding table of the optical element, the holding table and the optical element can be moved from a normal use state without moving the low melting point metal such as indium. Can be fused. As a result, the cooling efficiency can be remarkably improved as compared with the case where the holding table having the conventional cooling means is used. In particular, when the holder for the optical element has a driving / swinging mechanism, it is possible to greatly reduce the labor required for removing, attaching, and aligning the holder when attaching the optical element.
Further, the present invention can be applied to an optical system in which deformation and alteration due to heat caused by irradiation of synchrotron radiation light are concerned.

[Brief description of the drawings]

FIG. 1 is a basic schematic diagram of an optical element holder according to one embodiment of the present invention, and FIG. 2 is a perspective view showing the most basic case when the holder of FIG. 1 is used. . 1: Holder, 2: Heater, 3: Indium foil, 4: Optical element.

Claims (7)

(57) [Claims] 1. A holding table for holding an optical element used for a synchrotron radiation light source, wherein a heating means is provided below a surface in contact with the optical element. Stand. 2. The holding table for an optical element according to claim 1, wherein the holding table is made of a material having a thermal expansion coefficient substantially equal to that of the optical element. 3. The optical element holder according to claim 1, wherein the optical element holder is made of an alloy containing nickel. 4. A holding table for an optical element according to claim 1, wherein the holding table is made of the same material as the optical element. 5. The holding table according to claim 1, wherein the optical element is an X-ray reflecting mirror. 6. The holding table for an optical element according to claim 1, further comprising a cooling means below a surface in contact with the optical element. 7. A holding table for holding an optical element used for a high-intensity light source, wherein a heating means is provided below the surface in contact with the optical element. A method for holding an optical element, characterized by melting a low melting point metal by the heating means and fusing and holding the optical element on a holding table with the low melting point metal.