JPS6361200A - X-ray condensing multilayer film spectroscopic element - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is capable of determining the crystal structure, chemical state, chemical composition, and impurity concentration of minute regions by methods such as X-ray diffraction, X-ray photoelectron spectroscopy, and fluorescence X-ray intensity measurement. The present invention relates to a spectroscopic element for obtaining focused, powerful monochromatic X-rays necessary for a device for highly sensitive analysis.

<Prior Art> As conventional techniques for condensing monochromatic X-rays, the following two methods are used. The first method is to use an x4g condensing mirror together with a spectroscopic element. In this method, white X-rays are made monochromatic by being diffracted by a flat crystal spectroscopic element, and then the monochromatic X-rays are focused using a focusing mirror. In order to completely reflect the X-rays, it must be used at an oblique incidence of 1° or less, so
This method has the disadvantage that a large X-ray condensing mirror must be prepared in addition to the spectroscopic element, making the optical system complicated. The second method is to use a curved crystal spectroscopic element. In this method, white X-rays are diffracted by a crystal spectroscopic element, thereby simultaneously monochromating and condensing the light, and the optical system is simpler than in the first method. However, it has the disadvantage that it is difficult to produce curved crystals. In order to focus monochromatic X4s in the horizontal and vertical directions, the flat crystal must be bent into a predetermined shape in the vertical and horizontal directions, but it is difficult to bend the crystal accurately in both directions. If the flat crystal is thin, it is easy to bend, but it is also easy to break, and if it is thick, it is difficult to bend. In addition, if the X-ray incident on the curved crystal is a white Xi beam, the angle of incidence of the beam on the M crystal changes slightly in the vertical direction of the beam, so the wavelength of the X-ray monochromated by Bragg diffraction is vertical. There is a slight change in direction. In other words, the monochromatic X-rays are not completely monochromatic, and as a result, the wavelength resolution of the focused monochromatic X-rays is poor.

In this way, conventional devices use natural crystal spectroscopic elements that are difficult to bend into a predetermined shape and cannot control the crystal plane spacing, which poses the problem of not being able to fully emit X-rays of a single wavelength. .

SUMMARY OF THE INVENTION An object of the present invention is to provide an X-ray condensing multilayer film spectroscopic element that can overcome the disadvantages of the prior art described above.

Means and operation for solving the above problems In order to achieve the above object, the present invention uses a substrate whose surface is polished into a paraboloid of revolution shape.

Here, a paraboloid of revolution is a parabolic curve (for example, y2=a
x, where a is arbitrary) is a surface formed as a locus when rotated around an axis (X-axis). This paraboloid of revolution is formed by surface polishing, and unlike conventional natural crystal spectroscopic elements, it is not formed by bending or the like.

The curvature of this paraboloid of revolution is determined from the angle of incidence of the white X-ray beam that enters the spectroscopic element and the distance to the point where the white X-ray beam is focused. If an artificial multilayer film having a Bragg diffraction effect equivalent to that of a crystal is deposited on this paraboloid of revolution, this artificial multilayer film will have a shape that follows the paraboloid of revolution. Therefore, when a white X@ beam is made incident on the artificial multilayer film (in the above example, made parallel to the At the same time, Bragg diffraction occurs. However, since the substrate is a paraboloid of revolution, the angle of incidence changes little by little in the vertical direction of the white X-ray beam (see the direction of arrow A in FIGS. 1 and 2). Therefore, when a natural crystal with a constant lattice spacing is used, it will not be completely monochromatic.

Therefore, in the present invention, the periodic length of the two-layer film, which corresponds to the interplanar spacing of the crystal, is continuously changed in the vertical direction so as to be corrected in accordance with the change in the incident angle.
The white X-ray beam focused on a point becomes completely monochromatic.

Embodiments> FIG. 1 is a diagram for explaining the present invention in detail, in which 1 is a white X-ray beam, 2 is an X-ray condensing multilayer film spectroscopic element of the present invention, and 3 is a diagram for explaining the present invention in detail.
is a focused monochromatic X-ray. FIG. 2 is a diagram showing the relationship between the cross-sectional structure of the white X-ray beam of the present spectroscopic element in the vertical direction A and the incident angle of the white light x1s incident on the present spectroscopic element, and 4 is the substrate 5 of the present spectroscopic element. is the artificial multilayer film of this spectroscopic element, d- is the periodic length of the multilayer film on the upper side of this spectroscopic element, and do is the polyN! at the center of this spectroscopic element. I film periodic length, d+ is the multilayer film periodic length on the lower side of the spectroscopic element, and θ is the incident angle of the white X-ray beam on the upper side of the spectroscopic element, θ. is the incident angle of the white X-ray beam to the center of the present spectroscopic element, and θ- is the incident angle of the white X-ray beam to the lower side of the present spectroscopic element.

Incident angle θ of white X-ray beam. and monochromatic X from spectroscopic element 2
The basic equation of the parabolic curve is uniquely determined by the distance to the point where the line is focused, for example θ. =10 degrees, L=5
00 cm, y2 = 60.3073
8 x, and by rotating this parabolic curve about the X axis, a paraboloid of rotation is formed. The artificial multilayer film 5 on the substrate 4 has each layer having a similar paraboloid of revolution shape, and focuses the Bragg diffracted light at a distance of L. If the size of this spectroscopic element 2 is 8 cm on a side, y2=
60. In the parabolic curve of 30738x, the angle of incidence of the white x cotton parallel beam is θ-=0.9 with respect to the vertical direction A of the white xR.
96θ.

changes almost linearly from to θ = 1.0040°, and if d = d ~, then the wavelength of the focused monochromatic X-ray is λ = 2d
o Yuu θ. However, depending on the change in the incident angle, the periodic length of the multilayer film is changed to d.
-= 0.996 do to d+= 1.004 do
The focused monochromatic X-rays have a completely single wavelength. As is clear from these results, the light focusing characteristics and X-ray monochromaticity are improved compared to the conventional technology.

<Effects of the Invention> As explained above, by using this spectroscopic element, it is possible to completely monochromate and focus the parallel white X-ray beam, so it has the advantage of being able to irradiate a minute region of an object with highly accurate monochromatic X-rays. This allows microscopic areas to be analyzed with high sensitivity and precision using X-rays.

[Brief explanation of drawings]

Figures 1 and 2 relate to an embodiment of the present invention. Figure 1 is an explanatory diagram of how to use it, and Figure 2 is an illustration of the incident angle of the white x-ray beam and the vertical direction Z of the white x-ray beam. FIG. 2 is an explanatory diagram showing a cross section of an X-ray condensing polylithic film spectroscopic element. In the figure, 1 is a white X-ray beam, 2 is an X-ray filter 7J film spectroscopic element, 3 is a focused monochromatic X-ray, 4 is a substrate, 5 is an artificial multilayer film, d-, do, d+ (The periodic length of the artificial multilayer film, θ-1θ. θ is the angle of incidence. Patent applicant: Nippon Telegraph and Telephone Corporation, attorney, Shibe Mitsuishi (and one other person)

Claims (1)

[Claims] An artificial multilayer film having a Bragg diffraction effect equivalent to that of a crystal is deposited on a substrate whose surface has been polished into a paraboloid of revolution. An X-ray condensing multilayer film spectroscopic element characterized in that a white X-ray beam condensed in the horizontal and vertical directions at a predetermined distance is made monochromatic by continuously changing the vertical direction of the X-ray beam.