JPH06148397A - Spectral element for x rays - Google Patents

Abstract

PURPOSE:To prevent incidence of a diffracted X ray from a substrate onto an X-ray detector in a spectral element for X rays having an artificial accumulated film. CONSTITUTION:In a spectral element 1 for X rays having an artificial accumulated film 3 provided on the surface 2a of a substrate 2A, the substrate 2A is constructed of an amorphous material. In a spectral element 1 for X rays having the artificial accumulated film 3 provided on the surface 2a of a substrate 2 formed of a crystalline material, in another way, the lattice face 3a of the aforesaid artificial accumulated film 3 is tilted to the lattice face 2c of a crystal reflecting a diffracted X ray B4 of an element to be a disturbing spectrum to the spectrum of an analytical element, so that the diffracted X ray B4 may not enter an X-ray detector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray spectroscopic element provided with an artificial accumulating film on the surface of a substrate.

[0002]

2. Description of the Related Art Conventionally, this type of spectroscopic element has been used as a monochromator for an X-ray diffractometer, a fluorescent X-ray analyzer and the like. The fluorescent X-ray analysis apparatus is an apparatus that performs elemental analysis of a sample by irradiating the sample with primary X-rays and measuring fluorescent X-rays generated from the sample. This fluorescence X
An example of the line analyzer is shown in FIG.

In FIG. 2, the X-ray tube 10 is a primary X-ray B.
1, and the sample 6 is irradiated with the primary X-ray B1. The primary X-ray B1 applied to the sample 6 excites the atoms of the sample 6 to generate fluorescent X-ray B2 peculiar to the element. The fluorescent X-ray B2 from the sample 6 passes through the field limiting slit 11 and the first solar slit 12 and enters the spectroscopic element 1 at an incident angle θ. As shown in FIG. 3, the spectroscopic element 1 includes, for example, molybdenum Mo on a surface (cutout surface) 2a of a substrate 2 made of a crystalline material such as a silicon wafer.
And an artificial cumulative film 3 made of boron carbide B ₄ C.

Fluorescent X-ray B2 incident on the spectroscopic element 1
As is well known, only the fluorescent X-ray B2 having a predetermined wavelength that satisfies the following Bragg's equation is diffracted as the diffracted X-ray B3 by the artificial cumulative film 3 at the same diffraction angle θ as the incident angle θ. . 2dsin θ = nλ d: surface spacing θ: incident angle, diffraction angle λ: wavelength of X-ray n: order of reflection Diffracted X-ray B3 passes through the second solar slit 14 in FIG. The light enters the detector 15 and is detected. Elemental analysis of the sample 6 is performed based on this detected value.

[0005]

The spectroscopic element 1 having the artificial accumulating film 3 of FIG. 3 is used for spectroscopic analysis of light element spectra. For example, the sample 6 (FIG. 2) is used. When the analysis target is beryllium Be in the copper alloy, the desired analysis accuracy may not be obtained. The inventor has conducted extensive research on this reason and completed the present invention. The reason will be described below.

FIG. 4 shows the relationship between the incident angle θ and the detected X-ray intensity for a sample made of a copper alloy. As can be seen from this figure, since Be is a light element, its characteristic X-ray (fluorescent X-ray), the Be-Kα line, appears in a wide angle range, and Be has a small energy. The counting efficiency of the X-ray detector 15 (FIG. 2) is low, and its detection sensitivity is poor. Therefore, unlike other heavy elements and the like, it is necessary to slightly widen the angle range A of the incident angle θ of the fluorescent X-rays B2 entering the spectroscopic element 1 (FIG. 2) to increase the intensity of the detected X-rays.

On the other hand, when nickel Ni, cobalt Co, etc. are contained in the sample 6 (FIG. 2), the fluorescent X-rays, Ni-Kα rays and Co-Kβ rays, have higher energy than Be-Kα rays. Is large, it passes through the artificial cumulative film 3 of FIG. 3 and reaches the surface (cutout surface) 2a of the substrate 2. Here, since the surface 2a of the substrate 2 needs to be in a mirror surface state, a crystalline material such as a silicon wafer which is relatively easily available is used as the substrate 2. Therefore, the surface 2a
The fluorescent X-rays (proper X-rays) B2 of heavy elements such as Ni-Kα rays and Co-Kβ rays that have reached the
Is diffracted as indicated by a broken line in FIG. 4 and enters the X-ray detector 15 (FIG. 2) as a diffracted X-ray B4, and as shown in FIG.
It overlaps with e-Kα ray. Therefore, the diffracted X-ray B4, which becomes the above-mentioned interference, is included in the analysis range A, and the sensitivity of Be-Kα ray is remarkably poor (about 1/100) as compared with Ni-Kα ray and Co-Kβ ray. The accuracy is significantly reduced.

The present invention has been made in view of the above conventional problems, and an object thereof is to disperse X-rays diffracted from a substrate into an X-ray detector in an X-ray dispersive element having an artificial cumulative film. Is to prevent.

[0009]

In order to achieve the above object, the invention according to claim 1 provides an artificial cumulative film on a substrate made of an amorphous material. According to the invention of claim 1, since the substrate is made of an amorphous material, X-rays that have reached the substrate through the artificial cumulative film are not diffracted.

According to a second aspect of the present invention, there is provided an X-ray spectroscopic element in which an artificial cumulative film is provided on the surface of a crystalline substrate.
The lattice plane of the artificial accumulating film is inclined with respect to the lattice plane of the crystal that reflects the above-mentioned diffracted X-rays so that the diffracted X-rays of the element that become the interference spectrum with respect to the spectrum of the analysis element do not enter the X-ray detector. ing. According to the invention of claim 2, since the lattice plane of the artificial accumulating film is inclined with respect to the lattice plane of the crystal, the diffraction X-ray diffracted by the artificial accumulating film and the diffraction X-ray diffracted by the crystal lattice plane of the crystal. The lines and are emitted in different directions.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows the first embodiment. In this figure, the substrate 2A is made of an amorphous material such as amorphous silicon or glass. In addition,
The surface 2a of the substrate 2A is mirror-finished. Other configurations are similar to those of the conventional example shown in FIGS. 2 and 3, and the same portions or corresponding portions will be denoted by the same reference numerals and detailed description thereof will be omitted.

In the above structure, the substrate 2 shown in FIG.
Since A is composed of an amorphous material, fluorescent X-ray B2
Is not diffracted by the substrate 2A even when it reaches the surface 2a of the substrate 2A through the artificial accumulating film 3. Therefore, there is no risk that the interfering Co-Kβ rays and Ni-Kα rays in FIG. 4 enter the X-ray detector 15 in FIG. As a result, analysis accuracy is significantly improved.

FIG. 1B shows a second embodiment. In this figure, a substrate 2 made of a crystalline material such as a silicon wafer is used.
The surface (cut surface) 2a of the crystal is a lattice plane of the crystal (for example, (10
It is inclined by an angle α with respect to the (0) plane). Therefore, the lattice plane 3 a of the artificial cumulative film 3 is also inclined by the angle α with respect to the crystal lattice plane 2 c of the substrate 2. The angle α is
The diffraction X-ray B4 of the element which becomes an interference spectrum with respect to the spectrum of Be which is the analysis element is the X-ray detector 15 of FIG.
It should be set so that it is not incident on
It is set to about 0.5 °. Other configurations are similar to those of the conventional example of FIG. 3, and the same portions or corresponding portions are denoted by the same reference numerals and detailed description thereof will be omitted.

In the above structure, the fluorescent X-ray B2 which has passed through the artificial accumulative film 3 of FIG. 1 (b) is diffracted at the crystal lattice plane 2c. However, since the crystal lattice plane 2c is inclined with respect to the lattice plane 3a of the artificial accumulating film 3, the incident angle θ with respect to the lattice plane 3a of the artificial accumulating film 3 and the crystal lattice plane 2c.
Since the incident angle θ1 with respect to is different from each other, the emission direction of the diffracted X-ray (Be-Kα line) B3 and the emission direction of the diffracted X-ray (Ni-Kα line, Co-Kα line) B4 are mutually different. different. Therefore, by setting the inclination angle α to an appropriate value, the fluorescent X-ray B4 of the heavy element can be changed as shown in FIG.
Can be prevented from entering the X-ray detector 15.

[0015]

As described above, according to the invention of claim 1, since the substrate is made of the amorphous material, it is possible to prevent the diffracted X-rays from being emitted from the substrate. On the other hand, according to the invention of claim 2, since the lattice plane of the artificial cumulative film is inclined with respect to the lattice plane of the crystal forming the substrate, the diffracted X-rays emitted from the substrate enter the X-ray detector. Can be prevented.

[Brief description of drawings]

1A is an enlarged cross-sectional view of an X-ray spectroscopic element showing a first embodiment of the present invention, and FIG. 1B is an X section showing a second embodiment.
It is an expanded sectional view of a spectroscopic element for rays.

FIG. 2 is a schematic configuration diagram of a general fluorescent X-ray analyzer.

FIG. 3 is an enlarged cross-sectional view showing a conventional spectroscopic element.

FIG. 4 is a characteristic diagram showing a spectrum detected when a conventional spectroscopic element is used.

[Explanation of symbols]

1 ... Spectroscopic element, 2, 2A ... Substrate, 2a ... Surface, 2c ... Crystal lattice plane, 3 ... Artificial cumulative film, 3a ... Artificial cumulative film lattice plane, 15 ... Detector, B4 ... Interfering diffracted X-ray .

Claims (2)

[Claims] 1. An X-ray spectroscopic element having an artificial cumulative film formed on a surface of a substrate, wherein the substrate is made of an amorphous material. 2. In an X-ray spectroscopic element in which an artificial accumulation film is provided on the surface of a crystalline substrate, the diffraction X-ray of the element which becomes an interference spectrum with respect to the spectrum of the analysis element is X.
An X-ray spectroscopic element, characterized in that the lattice plane of the artificial accumulative film is inclined with respect to the lattice plane of the crystal that reflects the diffracted X-rays so as not to enter the line detector.