JP7264917B2 - Manufacturing method of X-ray conduit - Google Patents

Description

The present invention relates to a method for manufacturing an X-ray conduit, an X-ray conduit and an analyzer.

Conventionally, there has been known an analysis apparatus called an X-ray analysis microscope in which X-rays emitted from an X-ray source are narrowed by an X-ray tube, and the sample is irradiated with a small spot diameter (for example, patent See Reference 1).
An X-ray tube is an optical component that collects and guides X-rays from the other end of the glass tube by reflecting the X-rays incident from the X-ray source on the inner surface of the glass tube. The X-ray tube has, for example, a cylindrical, conical, ellipsoidal or parabolic shape of the inner surface of the glass tube.

Patent No. 5005461

Conventional X-ray conduits suffer from the problem of reduced transmission efficiency. The reason for this is that since the X-ray tube is a thin tube made of glass, the critical angle of total reflection θc is small, so the solid angle for taking in X-rays at the incident side end is small, so that many X-rays can be collected. This is because the light cannot be sent to the exit side end. The reduction in transmission efficiency described above becomes more pronounced as the X-ray energy increases, because the total reflection critical angle θc further decreases.

SUMMARY OF THE INVENTION An object of the present invention is to increase the efficiency of X-ray passage in an X-ray conduit.

A plurality of aspects will be described below as means for solving the problem. These aspects can be arbitrarily combined as needed.

A method according to one aspect of the present invention is a method of manufacturing an X-ray conduit for emitting X-rays incident from an X-ray source, comprising the following steps.
◎ A step of preparing a capillary body having a space inside the capillary into which X-rays are incident ◎ A step of forming a metal thin film on the inner wall surface of the capillary by the atomic layer deposition method

In this method, since the metal thin film is formed on the inner wall surface of the capillary of the X-ray conduit, the X-ray transmission efficiency can be improved.
Furthermore, since the metal thin film is formed by the atomic layer deposition method, the film thickness is uniform even within the elongated capillary space.
For example, glass capillaries for guiding X-rays are manufactured by pouring liquid glass into a mold, molding it into a capillary shape, then heat-treating it, or stretching the liquid glass and molding it into a capillary shape. be. A capillary manufactured by such a manufacturing method has a very small surface roughness, so that when used as an X-ray guide, the scattering loss of X-rays can be reduced. On the other hand, the atomic layer deposition method can form a film having a surface roughness approximately equal to that of the substrate, since it is characterized in that it can form a film layer by layer. Therefore, by applying the present invention, it is possible to form a metal film having a surface roughness substantially equal to the small surface roughness of a glass capillary.

The aspect ratio of the capillary body may be in the range of 500-10,000.
In this method, since the metal thin film is formed by atomic layer deposition, the film thickness is uniform even within the elongated capillary space.

An X-ray conduit according to another aspect of the present invention is for collecting and emitting X-rays incident from an X-ray source, and includes a capillary body and a metal thin film.
The capillary body has an intracapillary space into which the X-rays are incident.
The metal thin film is deposited on the inner wall surface of the capillary by atomic layer deposition.
For example, glass capillaries for guiding X-rays are manufactured by pouring liquid glass into a mold, molding it into a capillary shape, then heat-treating it, or stretching the liquid glass and molding it into a capillary shape. be. A capillary manufactured by such a manufacturing method has a very small surface roughness, so that when used as an X-ray guide, the scattering loss of X-rays can be reduced. On the other hand, the atomic layer deposition method can form a film having a surface roughness approximately equal to that of the substrate, since it is characterized in that it can form a film layer by layer. Therefore, by applying the present invention, it is possible to form a metal film having a surface roughness substantially equal to the small surface roughness of a glass capillary.

In this X-ray conduit, the metal thin film is formed on the inner wall surface of the capillary of the X-ray conduit, so that the X-ray transmission efficiency can be enhanced.
Furthermore, since the metal thin film is formed by the atomic layer deposition method, the film thickness is uniform even in the elongated capillary space.

The aspect ratio of the capillary body may be in the range of 500-10,000.
In this X-ray tube, the metal thin film is formed by the atomic layer deposition method, so the film thickness is uniform even within the elongated capillary space.

An analyzer according to another aspect of the present invention comprises an X-ray conduit and an X-ray source for irradiating the X-ray conduit with X-rays.
The above effects can be obtained with this analyzer.

The analyzer may have multiple x-ray conduits of different types.
The analyzer may further comprise a switching device for switching between multiple x-ray conduits according to intended use.
In this analyzer, the x-ray conduits can be switched according to their intended use.

The method for manufacturing an X-ray conduit, the X-ray conduit, and the analyzer according to the present invention can increase the efficiency of X-ray passage.

FIG. 2 is a block diagram showing a schematic configuration of an analyzer; FIG. 2 is a partial cross-sectional view of an x-ray conduit; The schematic diagram of a film-forming apparatus. Flowchart of a film forming method.

1. First Embodiment (1) General Description of Analysis Apparatus An analysis apparatus 1 will be described with reference to FIG. FIG. 1 is a block diagram showing a schematic configuration of an analyzer.
The analyzer 1 is an X-ray analytical microscope that performs qualitative/quantitative analysis of physical properties of the sample S by irradiating the sample S with primary X-rays and measuring fluorescent X-rays generated at that time.

The analysis apparatus 1 includes a sample box 3 that stores a sample S to be analyzed, an X-ray tube 5 that generates X-rays to irradiate the sample S, and a vacuum that is arranged between the X-ray tube 5 and the sample box 3. box 7;
The X-ray tube 5 is attached to the upper surface of the vacuum box 7 via the communicating portion 9 . The vacuum box 7 is attached to the upper surface of the sample box 3 via a communicating portion provided with an X-ray transmission window 11 that allows X-rays to pass through well.

A sample stage 13 is installed at a predetermined position in the sample box 3, and the sample S is placed thereon. An optical element unit 21 (described later) is arranged at a predetermined position inside the vacuum chamber 7 . With such a configuration, the X-rays generated by the X-ray tube 5 pass through the communicating portion 9 and enter the vacuum box 7, pass through the optical element unit 21 in the vacuum box 7, and further pass through the X-ray transmission window 11. , enter the sample box 3 and irradiate the sample S on the sample stage 13 .
The sample stage 13 is driven by the sample stage drive unit 56 to rotate the X-ray irradiation direction (vertical direction in FIG. 1) and two mutually orthogonal directions (for example, horizontal direction and depth direction in FIG. 1) within a plane orthogonal to the irradiation direction. direction). The sample stage drive unit 56 is provided inside or outside the sample box 3 .

The vacuum box 7 is provided with an X-ray detector 35 for detecting fluorescent X-rays generated from the sample S when the sample S is irradiated with X-rays as described above. In the example shown in FIG. 1 , the X-ray detector 35 is attached to the vacuum box 7 with the detection surface for detecting fluorescent X-rays facing the X-ray transmission window 11 .
An observation unit 57 such as a CCD (Charge Coupled Device) camera or an optical microscope is attached to the vacuum box 7 . As will be described later, the optical element unit 21 inside the vacuum chamber 7 has a mirror 28, and the observation section 57 is arranged to face the mirror 28. As shown in FIG.

The optical element unit 21 narrows the beam diameter of the X-rays generated by the X-ray tube 5 and irradiates the sample S with the X-rays. The optical element unit 21 is configured by mounting a plurality of X-ray conduits 29 and 31 as optical elements on an optical element switching stage 27 . The optical element switching stage 27 is a member for switching the plurality of X-ray conduits 29 and 31 according to the purpose of use.
The X-ray conduits 29 and 31 emit X-rays generated by the X-ray tube 5 and incident on the vacuum chamber 7 . The X-ray conduits 29 and 31 are capillaries made of, for example, glass in a cylindrical (tubular) shape, guide X-rays incident from one end while reflecting them on the inner surface, and emit them from the other end.

By using the X-ray conduits 29 and 31, a narrow and high-intensity X-ray beam system can be realized, and therefore a minute area can be measured and analyzed at high speed.
A mirror 28 is attached to the optical element switching stage 27 in addition to the X-ray conduits 29 and 31 .

The optical element switching stage 27 is configured to be movable in two mutually orthogonal directions within a plane orthogonal to the X-ray irradiation direction (vertical direction in FIG. 1) by the switching stage driving unit 55 . The switching stage drive unit 55 is configured using, for example, a stepping motor.
By moving the optical element switching stage 27 by the switching stage driving unit 55, the positions of the respective X-ray conduits 29, 31 and the mirror 28 are switched, and through the X-ray conduits 29, 31 arranged at predetermined positions, X-rays generated by the X-ray tube 5 are delivered to the sample S.
X-rays emitted from the X-ray conduits 29 and 31 arranged at predetermined positions pass through the X-ray transmission window 11 and are irradiated onto the upper surface of the sample S, and fluorescent X-rays are generated from the sample S by the irradiation of the X-rays. do. Fluorescent X-rays generated from the sample S reach the X-ray detector 35 through the X-ray transmission window 11 and are detected by the X-ray detector 35 .

The X-ray detector 35 is a device for detecting fluorescent X-rays generated by irradiating the sample S with X-rays, and outputs a signal proportional to the energy of the detected fluorescent X-rays. The X-ray detector 35 is connected to a signal processing section 52 that processes the signal output from the X-ray detector 35 . The signal processing unit 52 counts the signals of each value output by the X-ray detector 35 and performs processing to generate the relationship between the energy of the fluorescent X-rays and the count number, that is, the spectrum of the fluorescent X-rays. An analysis unit 53 is connected to the signal processing unit 52 . The signal processing unit 52 outputs data representing the generated spectrum to the analysis unit 53 . The analysis unit 53 includes a calculation unit that performs calculations and a memory that stores data. The analysis unit 53 performs qualitative analysis or quantitative analysis of the elements contained in the sample S based on the spectrum indicated by the data input from the signal processing unit 52 .

The X-ray tube 5 , signal processing section 52 , analysis section 53 , display section 54 , switching stage driving section 55 and sample stage driving section 56 are connected to control section 51 . The control unit 51 is composed of a computer including an arithmetic unit and a memory. The control unit 51 controls operations of the X-ray tube 5 , the signal processing unit 52 , the analysis unit 53 , the display unit 54 , the switching stage driving unit 55 and the sample stage driving unit 56 . The control section 51 may be configured to receive an instruction from the user and control the operation of each section of the analyzer 1 according to the received instruction. The display unit 54 may display the spectrum generated by the signal processing unit 52 or the analysis result by the analysis unit 53 . Also, the control unit 51 and the analysis unit 53 may be configured by the same computer.

(2) Detailed description of the X-ray conduits The X-ray conduits 29 and 31 are thin tubes with hollow inner surfaces having a paraboloid of revolution or a cylindrical reflecting surface, and emit primary X-rays introduced from the proximal end. , to irradiate or focus on the sample S with different spot diameters from the tip.
The X-ray conduits 29, 31 have capillary bodies 29a, 31a. The capillary bodies 29a, 31a are cylindrical tubes made of glass. That is, the capillary bodies 29a and 31a have a capillary inner space 32 (FIG. 2) which is a hollow hole into which X-rays are incident. The capillary bodies 29a and 31a have different lengths, with the capillary body 29a being longer and the capillary body 31a being shorter in this example.

The length of the capillary bodies 29a, 31a is, for example, in the range of 50-100 mm.
The capillary diameter is, for example, in the range of 10-400 μm.

The aspect ratio of the capillary bodies 29a, 31a is in the range of 500-10,000, for example. Here, the aspect ratio is the ratio (h/w) between the height (h) of the inner surface shape of the capillary inner space 32 and the diameter (w) of the circular or nearly circular horizontal cross-sectional shape.

Each of the X-ray conduits 29 and 31 has, for example, the same outer diameter and a different inner diameter. ) can be different. The capillary body 29a has a small inner diameter of the intra-capillary space 32 (for example, 10 μm), so the X-ray conduit 29 has a small focused spot diameter. In the capillary body 31a, the inner diameter of the intracapillary space 32 is large (for example, 100 μm), so the X-ray conduit 31 has a large focused spot diameter. That is, by condensing and irradiating X-rays to a narrower region by the X-ray conduit 29, analysis can be performed with higher resolution. On the other hand, the X-ray conduit 31 can emit more powerful X-rays, allowing faster measurement.

As shown in FIG. 2, a metal thin film 33 is formed on the inner peripheral surface 32a (an example of the capillary inner wall surface) of the capillary inner space 32 of the capillary main body 29a. FIG. 2 is a partial cross-sectional view of an x-ray conduit; A base material (for example, Cr) may be formed between the glass and the metal thin film.
The metal thin film 33 is made of silver, gold, or platinum, for example. Also, the metal thin film 33 is formed with a uniform thickness. The thickness of the metal thin film 33 is, for example, several ten nm to several μm, preferably 0.1 to 3 μm.

By providing the metal thin film 33, the critical angle θc can be increased compared to the case where the inner peripheral surface is made of glass, for example. As a result, the solid angle for taking in X-rays at the entrance-side facet is widened, and more X-rays can be collected and sent to the exit-side facet. As a result, the transmission efficiency of even high-energy X-rays is significantly improved, and a sufficiently high X-ray intensity can be obtained at the emission side facet.

The significance of the effects of this embodiment will be described in further detail.
The formula for obtaining the critical angle θc is as follows.
θc=1.64×10 ⁻³ λ√ρ (θc: critical angle, ρ: density of capillary inner wall surface material, λ: wavelength of incident X-ray)
Conventionally, when the capillary is brought closer to the X-ray source in order to capture more X-rays emitted from the X-ray source into the capillary, the X-rays with a large incident angle into the capillary enter at an angle greater than the critical angle inside the capillary. Since the angle becomes large, it may penetrate inside the capillary. This phenomenon is particularly noticeable with high-energy X-rays. The reason for this is that the energy is inversely proportional to the wavelength λ in the above formula, so that the higher the energy, the smaller the critical angle and the greater the amount of X-rays that pass through the inside of the capillary. This phenomenon occurs in both monocapillary and polycapillary capillaries, but this phenomenon is more conspicuous in polycapillaries than in monocapillaries because the inner walls of the capillaries are generally thinner.
In the X-ray conduits 29 and 31 of the present embodiment, the metal thin film 33 is formed on the inner peripheral surface 32a (capillary inner wall surface) of the capillary body 29a. The angle θc can be set large.

金属薄膜３３は、後述するように原子層堆積法によって形成されているので、細長いキャピラリ内空間３２内でも膜厚が他の製造方法（例えば、メッキ）によって形成された場合よりもさらに均一になっている。
Ｘ線導管２９とＸ線導管３１は、分析対象によって金属薄膜の材料が異なるものとしてもよい。例えば、Ｘ線導管の選択において、蛍光Ｘ線エネルギースペクトルにおいて、対象測定物の蛍光Ｘ線のピークと重ならない蛍光Ｘ線のピークを有する金属薄膜が形成されたＸ線導管を選ぶことができる。As shown in the table below, as an example of the present embodiment, when Pt is used as a metal thin film on the inner wall surface of the capillary, compared to the conventional case where the inner wall surface of the capillary is _SiO2 , It can be seen that the critical angle and solid angle are increased.

Since the metal thin film 33 is formed by the atomic layer deposition method as will be described later, the thickness of the metal thin film 33 is more uniform than when it is formed by another manufacturing method (for example, plating) even in the elongated capillary space 32 . ing.
The X-ray conduit 29 and the X-ray conduit 31 may have different metal thin film materials depending on the object to be analyzed. For example, when selecting an X-ray conduit, an X-ray conduit formed with a metal thin film having a fluorescent X-ray peak that does not overlap the fluorescent X-ray peak of the object to be measured in the fluorescent X-ray energy spectrum can be selected.

(3) Film Forming Apparatus A film forming apparatus 71 for manufacturing the X-ray conduit 29 will be described with reference to FIG. FIG. 3 is a schematic diagram of a film forming apparatus. The following description is the same for the X-ray conduit 31 as well.
The film forming apparatus 71 uses the ALD method. The ALD (Atomic Layer Deposition) method is a film deposition method that forms thin films by chemical replacement through periodic supply of each reactant.

The film forming apparatus 71 has a film forming chamber 72 . Inside the film forming chamber 72 , the capillary body 29 a is mounted on a mounting table 73 . The mounting table 73 is supported by a support portion 75 . The film forming chamber 72 is provided with a reactive gas (H ₂ O) inlet 77 , a raw material gas inlet 79 that serves as a raw material of the metal compound, and a purge gas inlet 81 . An exhaust port 83 for exhausting gas from the film forming chamber 72 is provided on the right side of the film forming chamber 72 .

(4) Film Forming Method A film forming method for forming the metal thin film 33 on the wall surface of the capillary space 32 by atomic layer deposition will be described with reference to FIG. FIG. 4 is a flow chart of the film forming method.
In step S1, after the capillary body 29a is installed in the film forming chamber 72, a raw material gas as a raw material for the metal thin film 33 is supplied to the capillary body 29a.

In step S2, the raw material A in the reaction chamber is exhausted by purging the inert gas.
In step S<b>3 , reactive gas is supplied to the film forming chamber 72 . Oxygen, water vapor, or the like can be used as the reactive gas. As a result, an atomic layer of oxygen is formed on the atomic layer made of the raw material.
In step S4, in order to remove by-products and reactive gases generated in the gas phase, the chamber is evacuated by purging with an inert gas.

The above S1 to S4 are repeated to form the metal thin film 33 .
Thereafter, in step S5, a film thickness measuring device (not shown) provided in the film forming device 71 is used to confirm whether or not the metal thin film 33 has reached a predetermined film thickness.
In the film forming method described above, since the film forming material is a gas, there is an additional advantage that the material can be reliably sent to the space inside the capillary even if the capillary is narrow. On the other hand, in the vapor deposition method and the plating method, in the case of a narrow capillary, it is difficult for the film-forming raw material to enter because the entrance of the capillary is narrow.

2. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the invention. In particular, multiple embodiments and modifications described herein can be arbitrarily combined as needed.
Although a monocapillary was described as an X-ray conduit in the above embodiment, a polycapillary may be used as the X-ray conduit. However, from the viewpoint that a higher X-ray emission intensity is required, the advantage of the present invention is greater in the case of a monocapillary.
The number of X-ray conduits provided in the analyzer may be one, or three or more.

INDUSTRIAL APPLICABILITY The present invention can be widely applied to X-ray conduits used to focus or parallelize X-rays in an X-ray analyzer or the like that uses X-rays for analysis.

1: Analysis device 21: Optical element unit 29: X-ray conduit 29a: Capillary main body 31: X-ray conduit 31a: Capillary main body 33: Metal thin film 35: X-ray detector 71: Film formation device S: Sample

Claims (2)

A method of manufacturing an X-ray conduit for emitting X-rays incident from an X-ray source, comprising:
providing a capillary body having an intracapillary space into which the X-rays are incident;
forming a metal thin film that reflects the X-rays on the inner wall surface of the capillary by atomic layer deposition;
A method of manufacturing an X-ray conduit comprising: 2. The method of manufacturing an X-ray conduit according to claim 1, wherein the aspect ratio of said capillary body is in the range of 500-10,000.

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