JP2731501B2 - X-ray focusing element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray
The present invention relates to an X-ray optical element such as a line condensing element.

[0002]

2. Description of the Related Art An X-ray analyzer irradiates a sample with X-rays and analyzes the sample based on X-rays from the sample. In such an X-ray analyzer, there is a case where it is desired to analyze a specific minute portion (in the range of about 1000 to 100 μm) of a sample. In such a case, the intensity of the X-rays incident on the sample is reduced. To compensate for this, an X-ray focusing element is arranged in the optical path between the X-ray source and the sample, Has been made to increase the intensity of X-rays incident on.
FIG. 12 shows an example of this type of X-ray focusing element.

In FIG. 12, an X-ray focusing element 50 is
It is formed of a glass pipe having a tapered rectangular tube shape, and its inner surface is in a mirror surface state. In other words, the X-ray condensing element 50 is configured such that the surface 52 of the total reflection mirror 51 faces away from the total reflection mirror 51, and the total reflection mirror 5 moves toward the emission port 54.
One surface 52 is close to each other. The X-ray condensing element 50 passes the X-ray B1 from an X-ray source (not shown) from the entrance 53 to the exit 54 to irradiate the sample 61, and enters the surface 52 of the total reflection mirror 51. A part of the X-ray B1 is totally reflected as indicated by a dashed line, and the sample 61 is irradiated with the totally reflected X-ray B2. Thus, the sample 61 is irradiated with the total reflection X-rays B2 in addition to the X-rays B1, the X-rays are condensed, and the intensity of the X-rays irradiated on the sample 61 is increased.

[0004]

Here, X-rays B1, B
2 is a very small area of the sample 61, for example, 1000 °
To converge light in the range of about 100 μm, the opposite total reflection mirror 51 is placed at the output port 54 by, for example, several hundred
It must be close to each other to the extent. However, it is difficult to bring the pair of total reflection mirrors 51 close to each other to several μm or less, so that it is difficult to focus X-rays in an extremely small range as described above.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an X-ray condensing element capable of converging X-rays in an extremely small range.

[0006] In addition to the X-ray condensing element, in the case of an X-ray optical element, there is a case where it is desired to position the X-ray optical element with high dimensional accuracy with respect to an extremely small gap.
As a result of such positioning,
There is known a spectral element 10 in which an artificial multilayer grating 11 shown in FIG. 13 is provided on a substrate 12. The artificial multilayer lattice 11
For example, a reflection layer of a tungsten layer 11a and a silicon layer 11b as a spacer are alternately laminated, and the period d of the lattice spacing is set to be constant. Thereby, the spectroscopic element 10 diffracts the incident X-rays B1 according to the well-known Bragg equation, and reflects the monochromatic diffracted X-rays B33.

However, in this spectroscopic element 10, the X-ray B
Since the X-rays B1 and B33 pass through the silicon layer 11b, the X-rays B1 and B33 are absorbed by the silicon layer 11b, so that the intensity of the diffracted X-ray B33 decreases. Therefore,
Another object of the present invention is to perform positioning with high dimensional accuracy and to reduce X-ray absorption in an X-ray optical element that needs to set a very small gap.

[0008]

[Means and action in order to solve the problems] us the above-mentioned object
In order to achieve this, the X-ray focusing element according to claims 1 and 2
Form a coating on the surface of the total reflection mirror facing each other,
This coating is used to position both total reflection mirrors with each other.
The optical path of the X-ray condensing element constitutes a positioning spacer.
Only part of the space is occupied by the coating . Claim 1
According to the inventions of (a) and (b), the positioning space made of
The total reflection mirrors next to each other with high precision
X-rays can be collected in a predetermined extremely small area.
Can be lighted. Also, only a part of the optical path space is covered.
Occupied by film, X-ray absorption by film is small
Can be done. According to the invention of claim 1, the X-ray collection
Since a coating is formed on a part of the surface of the optical element ,
The absorption of X-rays by can be further reduced.

According to a third aspect of the present invention, in the first or second aspect, the surface of the mirror is made of, for example, an artificial multilayer grating that diffracts X-rays.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment. In FIG. 2, an X-ray source 2 emits an X-ray B1 toward a sample 3. An X-ray focusing element 4 is provided in an optical path between the X-ray source 2 and the sample 3 so as to focus the X-rays B1 on a minute portion of the sample 3 (for example, in a range of about 1000 ° to 100 μm). Irradiate with light.

FIG. 1 shows the condensing element 4 in an enlarged manner. In this figure, the light-collecting element 4 is a surface 1 of the total reflection mirror 1.
a are spaced apart from each other and arranged in an opposed state. In this embodiment, the total reflection mirror 1 is in the shape of a square tube, but may be in the shape of a cylinder, as long as at least one pair faces each other. The surfaces 1a of the total reflection mirror 1 are closer to each other as they approach from the entrance 4a near the X-ray source 2 (FIG. 1) to the exit 4b near the sample 3. That is, the optical path space S of the light condensing element 4 is narrowed.

The surface layer 1c of the above-mentioned total reflection mirror 1 is formed of, for example, an artificial multilayer lattice composed of a tungsten layer and a silicon layer. The period d of the lattice spacing of the artificial multilayer film lattice is set so as to increase linearly and continuously along the surface 1a as the distance from the X-ray source 2 (FIG. 1) increases, that is, as the distance from the exit 4b increases. Have been.

The size of the emission port 4b is, for example, 10
The angle is set to about 0 ° to 200 °, while the size of the entrance 4a is set to, for example, about 1 mm. The length L of the light-collecting element 4 in the optical axis direction A is set to, for example, about 50 mm, and the distance from the emission port 4b to the surface 3a of the sample 3 is set to, for example, about 3 mm.

Next, the main part of the present invention will be described. An emission port 4b is provided on the surface 1a of the two total reflection mirrors 1.
Is formed in the vicinity of. This coating 1d
For example, it is composed of a single element of a light element having a smaller atomic number than the element constituting the total reflection mirror 1, such as carbon, beryllium, and boron, or a compound thereof, and therefore almost absorbs X-rays B1, B2, and B3. Let through. The coatings 1d are in contact with each other and constitute a positioning spacer for positioning the total reflection mirror 1 at the exit 4b. The thickness of the coating 1d is set to, for example, 100 ° to 200 °, and the length L1 of the optical axis direction A is set to, for example, about 5 mm.

Next, the operation of the above configuration will be briefly described. Part of the X-ray B1 from the X-ray source (FIG. 2) passes from the entrance 4a to the coating 1d of the exit 4b,
The light enters the surface 3a of the sample 3 and the other part enters the surface 1a of the total reflection mirror 1 at a small angle, is totally reflected as indicated by a dashed line, and passes through the coating 1d of the exit 4b. ,
The light is focused on the surface 3a of the sample 3.

Here, by increasing the X-ray intensity by concentrating the X-rays B1 and B2 on a minute area of the sample 3, the analysis accuracy is improved, but the X-rays B1 and B2 are sufficiently collected. In order to emit light, the opening width of the emission port 4b is generally set to several hundreds.
Å It is preferable to set the width as narrow as the following. In contrast,
In this embodiment, a coating 1d is formed on the surface 1a of the total reflection mirror 1.
Are formed to form a positioning spacer, and since the coating 1d can be formed extremely thin and the thickness can be set with high precision, the opening width of the emission port 4b is set to an extremely small gap. be able to. Therefore, X-rays B1, B2
Can be sufficiently condensed, so that the analysis accuracy is improved.

In the conventional example shown in FIG. 12, the critical angle θc at which the X-ray B1 is totally reflected becomes smaller as the wavelength of the X-ray B1 becomes shorter, so that the short-wavelength X-ray B1 is hardly totally reflected. Therefore, a part of the short-wavelength X-rays B1 having a large energy enters the total reflection mirror 51 and is absorbed.
The sample 61 is not illuminated, so that it is not possible to focus another X-ray. As a result, the analysis accuracy does not improve.

On the other hand, in this embodiment, since the surface layer 1c of the total reflection mirror 1 is formed by the artificial multilayer film lattice of FIG. 1, the X-ray B1 incident on the total reflection mirror 1 is well known. Among them, some X-rays B1 are diffracted like a two-dot chain line, and the diffracted X-rays B3 pass through the coating 1d and are irradiated on the surface 3a of the sample 3. Therefore, the X-rays irradiated on the sample 3 include the X-rays B1 directly incident on the sample 3 from the X-ray source 2 (FIG. 2) and the diffracted X-rays B3 in addition to the total reflection X-rays B2. Strength increases.

X-ray B irradiated on the surface 3a of the sample 3
1, B2 and B3 excite the atoms of the sample 3 in FIG. 2 to generate fluorescent X-rays B4 unique to the elements contained in the sample 3. The fluorescent X-ray B4 enters the spectral element 5 and is separated therefrom.
The light enters the line detector 6. Elemental analysis is performed based on the incident fluorescent X-ray B4.

The X-ray diffraction condition is given by the following Bragg equation, as is well known. 2d · sin θ = nλ θ: incidence angle, diffraction angle λ: wavelength of X-ray n: order of reflection

When a mirror-finished single crystal is used as the total reflection mirror 1 in FIG. 1, the period d of the lattice spacing becomes small, so that the diffraction angle θ becomes growing. Therefore, since the diffraction angle θ is too large than the angle at which the total reflection X-ray B2 is generated, the short-wavelength X-rays among the X-rays B1 incident on the total reflection mirror 1 at a small angle (about 1 ° to 2 °) Are not diffracted.

On the other hand, the light-collecting element 4 forms an artificial multilayer grating on the surface layer 1c of the total reflection mirror 1,
This artificial multilayer lattice has a period d of lattice spacing larger than that of a single crystal.
Is large, the diffraction angle θ is relatively small. For example, when diffracting Cu-Kα ray (1,542 °),
Assuming that the period d of the lattice plane interval is 55 °, the diffraction angle θ is about 1.6 °. Therefore, the X-ray B1 having a short wavelength can be diffracted at a small angle close to a small angle at which total reflection occurs. As a result, X-rays having a short wavelength, that is, X-rays having a large energy can be diffracted and applied to the surface 3a of the sample 3, so that the analysis accuracy is improved.

Incidentally, the incident angle θ of the X-ray B1 to the total reflection mirror 1 becomes smaller as it goes in the optical axis direction A. Here, in this embodiment, the period d of the lattice plane interval is set to the output port 4b.
It is set larger as you go. Therefore, from the entrance 4a having a large incident angle θ to the exit 4 having a small incident angle θ.
Since the X-rays B1 having the same wavelength can be diffracted over b, the intensity of the diffracted X-rays B3 close to a single wavelength increases.

In this embodiment, since the surfaces 1a of the total reflection mirror 1 are brought closer to each other as approaching the exit 4b, the X-rays B1 are taken in at the large entrance 4a.
X-rays B1, B2 and B3 can be emitted from the small exit 4b. Therefore, the X-rays B1, B2, and B3 can be further focused on the minute portion of the sample 3.

By the way, in the above embodiment, the fluorescent X in FIG.
Although the example in which the X-ray condensing element 4 is used in the X-ray analyzer has been described, the present invention can also be used for diffraction X-ray analysis as shown in FIG. In the diffraction X-ray analysis, as shown in FIG. 3, an X-ray B1 from the X-ray source 2 is irradiated on the sample 3, and an X-ray B5 diffracted by the sample 3 is made incident on the X-ray detector 6, This is to analyze the structure of the crystal constituting Sample 3.

FIGS. 4A, 4B and 4C show modifications of the first embodiment. In the first embodiment shown in FIG. 1, the coating 1d constituting the positioning spacer is provided only near the exit 4b of the total reflection mirror 1, but as shown in FIG. It may be provided on the entire surface 1a of the mirror 1.

The coating 1d is formed as shown in FIG.
Of the total reflection mirrors 1 facing each other, it may be provided only in the vicinity of the emission port 4b on the surface 1a of one of the total reflection mirrors 1, or as shown in FIG.
It may be provided on the entire surface of one total reflection mirror 1.

In the first embodiment, the period d of the lattice spacing of the artificial multilayer lattice shown in FIG. 1 is changed along the surface 1a. However, as shown in FIG. 5, the period d is constant. Is also good. When the period d is constant, the wavelength of the diffracted X-ray B3 changes with the change of the diffraction angle θ, so that polychromatic X-rays can be obtained.

Further, in each of the above embodiments, the surface 1a of the total reflection mirror 1 is brought closer to the exit 4b of the light-collecting element 4, but as shown in FIG. May be set in parallel with each other. In this case, the positioning spacer made of the coating 1d is provided on both the entrance 4a and the exit 4b. As described above, even when the surfaces 1a of the total reflection mirror 1 are set parallel to each other, FIG.
As described above, the period d of the lattice spacing of the artificial multilayer lattice may be changed.

By the way, in each of the above embodiments, the case where a pair of the total reflection mirrors 1 is provided has been described. However, in the present invention, as shown in FIG. Good. Further, in each of the above-described embodiments of FIGS. 1 to 7, the artificial multilayer lattice is formed on the surface layer 1c of the total reflection mirror 1, but in the present invention, the artificial multilayer lattice is not formed, The total reflection mirror 1 may be formed of a metal film.

In each of the above embodiments, the coating 1d is made of a light element so that the X-rays B1 and B2 pass through the coating 1d. However, as in the embodiment shown in FIG. The entrance 4a and the exit 4b may be opened along the axial direction A. In this case, the coating 1d may be formed of the same heavy element as that of the total reflection mirror 1.

[0032]

In the above embodiment, the total reflection X-ray B2 and the diffraction X-ray B3 shown in FIG.
Although the case where reflection and diffraction are performed only once has been described, the present invention may reflect and diffract these X-rays B2 and B3 two or more times.

FIG. 10 shows a seventh embodiment. In the seventh embodiment, a light-collecting element 4 is provided at the tip of an X-ray tube 2 which is an X-ray source.
Is incorporated. In this light-collecting element 4, the coatings 1d, 1d at the tip of FIG. 1 are welded to each other. On the other hand, the light-collecting element 4 of FIG.
The X-ray tube 2 is fixed to the tube wall 2 a with screws 20, and the entrance 4 a side is sealed with a sealant 21. Therefore, the inside of the X-ray tube 2 and the sample chamber 22
Are sealed. For example, since the inside of the X-ray tube 2 is maintained at atmospheric pressure and the sample chamber 22 is maintained at a vacuum, the coating 1
d constitutes an X-ray transmission window. A seal ring 23 is inserted between the outer periphery of the X-ray tube 2 and the analyzer main body wall 24.

As a method of welding the coatings 1d, 1d at the tips, for example, the coatings 1d, 1d are made of a metal such as aluminum or a thermoplastic resin and are thermally welded to each other.
Other configurations are the same as those of the embodiment of FIG. 1 or FIG. 5, and the same or corresponding portions are denoted by the same reference characters and description thereof is omitted.

FIG. 11 shows an application example of the present invention . FIG.
In the above, the silicon layer (coating) 11c as a spacer of the spectroscopic element 10 is provided only at both ends of the tungsten layer (optical element) 11a as a reflection layer, and the X-ray B
The portion where B1 and B33 pass is a space 11d. Therefore, since the absorption of the X-rays B1 and B33 is reduced, the intensity of the diffracted X-ray B33 is increased.

[0037]

As described above, claims 1 and 2
According to the invention of (1), the positioning spacer made of a coating film is used.
The total reflection mirrors can be adjacent to each other
Can focus X-rays in a very small area
You. Also, only part of the optical path space is occupied by the coating
Therefore, X-ray absorption by the coating can be reduced.
You. According to the first aspect of the present invention, since the coating is formed on a part of the surface of the X-ray condensing element, the absorption of X-rays by the coating can be reduced.
It can be even smaller.

[0038]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an X-ray focusing element showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an X-ray fluorescence analyzer according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram when the X-ray focusing element according to the first embodiment of the present invention is used in a diffraction X-ray analyzer.

FIGS. 4 (a), (b), and (c) are schematic structural diagrams of an X-ray focusing element showing a modification of the first embodiment.

FIG. 5 is a schematic configuration diagram of an X-ray condensing element showing a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of an X-ray focusing element showing a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of an X-ray focusing element showing a fourth embodiment of the present invention.

FIG. 8 is a schematic perspective view of an X-ray focusing element showing a fifth embodiment of the present invention.

FIG. 9 is a schematic perspective view of an X-ray condensing element showing a sixth embodiment of the present invention.

FIG. 10 is a schematic side view, partially in section, of an X-ray tube incorporating an X-ray focusing element according to a seventh embodiment of the present invention.

FIG. 11 is a schematic sectional view of a spectral element showing an application example of the present invention.

FIG. 12 is a conceptual diagram showing a conventional X-ray condensing element.

FIG. 13 is a schematic sectional view showing a conventional spectral element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Total reflection mirror, 1a ... Surface, 1d ... Coating, 4 ... X-ray condensing element, 4a ... Inlet, 4b ... Outlet, 11a ... Tungsten layer (X-ray optical element), 11c ... Silicon layer ( B1: X-ray, B2: total reflection X-ray, B3: diffraction X-ray.

Claims (3)

(57) [Claims] An X-ray passes from an entrance port formed between both mirrors to an exit port by arranging the total reflection mirror so as to face each other. In the X-ray condensing element for performing total reflection and condensing, a coating is formed on a part of the surface of the total reflection mirror, and the coating constitutes a positioning spacer for positioning the two total reflection mirrors with each other, An X-ray condensing element, wherein only a part of the optical path space of the X-ray condensing element is occupied by the coating. 2. By arranging the total reflection mirror so as to face each other, X-rays are passed from the entrance to the exit formed between the two mirrors, and the X-rays are transmitted through the surface of the total reflection mirror. In the X-ray condensing element for total reflection and collection, a coating is formed on the surface of the total reflection mirror, and the coating forms a positioning spacer for positioning the two total reflection mirrors with each other. An X-ray condensing element, wherein only a part of the optical path space of the condensing element is occupied by the coating. 3. The mirror according to claim 1, wherein
Is made of an artificial multilayer grating that diffracts X-rays.
X-ray focusing element.