JPH1151883A - Method and equipment for fluorescent x-ray analysis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a highly accurate high sensitivity measurement through a simple structure by locating a spectroscopic element selectively at a predetermined position relative to a sample while bringing the spectroscopic element close to a detection means sufficiently. SOLUTION: A sample 1 is irradiated with first order X-rays 3. When fluorescent X-rays 7 are measured from the light element side having a long wavelength, a selecting means 9 sets a spectroscopic element 6A at a predetermined position relative to a sample 1. Fluorescent X-rays 5 emitted from the sample 1 are subjected to spectroscopy and the fluorescent X-rays 7 having a desired wavelength are directed toward a positional resolution detecting means 8. Subsequently, a spectroscopic element 6B corresponding to the fluorescent X-rays 7 on the heavy element side having a shorter wavelength is set at the predetermined position. When spectroscopic elements 6 corresponding to the fluorescent X-rays 7 on the heavy element side having a shorter wavelength are set sequentially at the predetermined position and the intensity distribution of the fluorescent X-rays 7 subjected to spectroscopy is measured, fluorescent X-ray analysis can be performed over a wide wavelength range without interlocking the spectroscopic element 6 and the positional resolution detecting means 8 with the sample 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluorescence analyzer and a method capable of performing highly accurate and highly sensitive measurement with a simple structure.

[0002]

2. Description of the Related Art Conventionally, in so-called wavelength-dispersive X-ray fluorescence analysis, as shown in FIG.
Is fixed, and the sample 1 is irradiated with the primary X-rays 3 from the X-ray source 4,
The fluorescent X-rays 5 generated from the sample 1 are diffracted by the spectroscopic element 26, and the X-rays 7 diffracted by the spectroscopic element 26 are detected by a detector 28 such as a proportional counter or a scintillation counter.
Here, the incident angle θ at which the fluorescent X-rays 5 enter the spectroscope 26
By continuously linking the extension line 30 of the fluorescent X-ray 5 and the spectral angle 2θ formed by the diffracted X-ray 7 with the linking means 29, the fluorescent X-ray 5 generated from the sample 1 is changed to various wavelengths. By spectroscopy, fluorescent X-rays 7 having a wavelength corresponding to each element included in the sample 1 can be detected. This interlocking means 29
This is a so-called goniometer, in which the spectroscopic element 26 is rotated about an axis O perpendicular to the paper surface passing through the center of the surface, and the detector 28 is rotated about the axis O by twice the rotation angle by twice the rotation angle.
Rotate along 1.

[0003]

However, as described above,
Since the spectroscopic element 26 and the detector 28 are linked, the configuration of the device becomes complicated, and the mechanical accuracy of the device and thus the accuracy of the measurement cannot be further improved. Further, in order to prevent the rotating spectroscopic element 26 and detector 28 from interfering with other portions, the sample 1 and the spectroscopic element 26 and the spectroscopic element 26 and the detector 28 cannot be sufficiently close to each other. 28
The fluorescent X-rays 7 incident on the light source diverge and attenuate, and the intensity and thus the measurement sensitivity cannot be further improved. On the other hand, in the so-called energy dispersive X-ray fluorescence analysis, such an interlocking means is not necessary, but the S / N ratio of the obtained signal is still insufficient due to the characteristics of a detector such as an SSD used.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a fluorescent X-ray analyzer and a method capable of performing highly accurate and highly sensitive measurement with a simple configuration.

[0005]

According to a first aspect of the present invention, there is provided a fluorescent X-ray analyzer, comprising: a sample stage on which a sample to be irradiated with primary X-rays is fixed; A plurality of different light-splitting elements; a selection means for selectively positioning the light-splitting element at a predetermined position with respect to the sample to split the fluorescent X-rays generated from the sample; Position resolution detecting means for measuring the intensity distribution of the obtained fluorescent X-rays.

According to the first aspect of the present invention, the spectroscopic element is selectively positioned at a predetermined position with respect to the sample, and the spectroscopic element and the detecting means are not linked to the sample. Can be measured. Also, the sample and the spectroscopic element,
Since the spectroscopic element and the detection means can be brought sufficiently close to each other, the divergence and attenuation of the fluorescent X-rays incident on the detection means are suppressed, and high-sensitivity measurement with sufficient intensity can be performed.

In the X-ray fluorescence analysis method of the present invention, the sample is irradiated with primary X-rays, and a plurality of spectral elements having different lattice spacings are selectively positioned at predetermined positions with respect to the sample. X-rays generated from the above are separated, and the intensity distribution of the separated fluorescent X-rays is measured by detecting means having a fixed position resolution with respect to the predetermined position. According to the method of the second aspect, the same operation and effect as those of the apparatus of the first aspect are obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an X-ray fluorescence spectrometer according to an embodiment of the present invention will be described with reference to the drawings, taking as an example a case where it is used for analyzing a minute portion of a sample. First, the configuration of this device will be described. As shown in the plan view of FIG. 1, this apparatus includes a sample stage 2 to which a sample 1 to be irradiated with primary X-rays 3 is fixed. Where primary X
The X-ray source generating the ray 3 is, for example, an SR light source (radiation light source) having a collimator having a diameter of 5 μm, and the primary X-ray 3
Are X-rays which are extremely thin but have higher intensity than before.

The apparatus further comprises a plurality of dispersive elements 6A, 6B... Having different lattice spacings, and the dispersive elements 6A, 6B.
B ... is selectively located at a predetermined position with respect to the sample 1,
Selection means 9 for dispersing fluorescent X-rays 5 generated from sample 1
And Here, the plurality of spectral elements 6A, 6B,...
The lattice spacing, so-called d value, differs depending on the wavelength of the fluorescent X-rays 7 to be separated (diffracted). For example, from the long wavelength side, a spectral crystal of ADP (NH ₄ H ₂ PO ₄ ) is used for fluorescent X-rays of chlorine to fluorescent X-rays of calcium, and fluorescent fluorescent light of vanadium is converted from fluorescent X-rays of potassium. For X-rays, a spectral crystal of silicon dioxide is used. For fluorescent X-rays of calcium to fluorescent X-rays of calcium, a spectral crystal of indium antimony is used. For X-rays, various lattice planes of the silicon crystal are used. In addition, it is also possible to use an artificial lattice made of a multilayered accumulation film having a desired d value.

The selecting means 9 comprises a plurality of spectroscopic elements 6A, 6B
Are a polygonal column fixed to each side, and a motor 9 for rotating the column 9a around a central axis 10.
b. The predetermined position with respect to the sample 1 at which the spectroscopic elements 6A, 6B... Are selectively positioned is defined as a position from the point of incidence P of the primary X-ray 3 on the sample 1 to the center Q of the surface of the spectroscopic element 6.
Is a predetermined distance, and the fluorescence X from P to Q
The position at which the incident angle θ _{Q of the} line 5 to the spectroscopic element 6 is a predetermined angle. In FIG. 1, the spectroscopic element 6A is at that position, and the fluorescent X-rays 5 generated from the sample 1 are incident thereon. Disperse it.

The apparatus further comprises a position resolution detecting means 8 fixed to the predetermined position and measuring the intensity distribution of the fluorescent X-rays 7 separated by the spectroscopic element 6A selected by the selecting means 9. ing. Here, as the position resolution detecting means 8, a so-called PSPC (Position Sensitive Proportional Counter), CCD, P
DA (photodiode array), IP (imaging plate) and the like can be used. It is to be noted that the position resolution detecting means 8 is fixed to the predetermined position, regardless of which spectral element 6A, 6B... Is selected, the selected spectral element 6A is fixed to the predetermined position. It is fixed at a position where the fluorescent X-rays 7 within a certain range to be split are incident, and means that the selected spectroscopic element 6A does not rotate or the like.

Next, the operation of the apparatus of this embodiment will be described. First, the sample 1 is irradiated with primary X-rays 3.
Here, assuming that the fluorescent X-rays 7 to be analyzed are measured from the longer wavelength side, that is, from the light element side, the corresponding spectroscopic element 6A is positioned at a predetermined position (position in FIG. ). As a result, the fluorescent X-rays 5 generated from the sample 1 are separated, and the fluorescent X-rays 7 having a desired wavelength travel to the position resolution detecting means 8. At this time, the d value of the spectroscopic element 6A, the incident angle of the fluorescent X-rays 5 (the reflection angle of the fluorescent X-rays 7) θ, and the wavelength λ of the fluorescent X-rays 7 satisfy the Bragg condition of the following equation (1). Fulfill.

2d sin θ = nλ (n is a diffraction order and a positive integer) (1)

[0014] Fluorescence incident angle theta of the X-ray 5, depends on the incident position of the spectral element 6A, for example theta ₁ 1
In the range of theta ₂ from (theta _1> theta _2), the theta angles of the incidence satisfied the expression (1), and, d values each spectral element 6A, is constant in 6B ..., spectral The wavelength λ of the fluorescent X-ray 7 obtained by the element 6A is also
It is in the range of ₁ to λ ₂ (λ ₁ > λ ₂ ). Here, in the apparatus of the present embodiment, the reflection angle is incident fluorescent X-ray 7 is simultaneously spread in the range of theta ₂ from theta _1, the position resolution of such PSPC that it can measure the intensity distribution in the direction (expanding direction) aligned The detection means 8 is used. Further, it can be known from Formula (1) which position in the distribution direction the fluorescent X-ray 7 of which wavelength is incident. Therefore, even if the position resolution detecting means 8 is fixed to the predetermined position, the intensity of the fluorescent X-rays 7 separated by the spectroscopic element 6A selected by the selecting means 9 at each of the wavelengths λ _{1 to} λ ₂ . Can be measured.

When the measurement using the spectroscopic element 6A is completed,
The selecting means 9 positions the spectral element 6B corresponding to the fluorescent X-ray 7 on the heavy element side with a shorter wavelength at a predetermined position (the position of the spectral element 6A in FIG. 1). This spectral element 6
The d value of B is set slightly smaller than the d value of the spectroscopic element 6A, and the wavelength range λ
_{3 to} λ ₄ are continuous with at least the wavelength range λ _{1 to} λ _{2 of the} fluorescent X-ray 7 that can be measured by the spectroscopic element 6A (λ ₃ ≧ λ
₂ ) and extend to shorter wavelength λ ₄ (λ ₄ <λ
₂ ).

In this way, the spectroscopic elements 6B... Corresponding to the fluorescent X-rays 7 on the side of the heavy element having a shorter wavelength are successively positioned at predetermined positions by the selecting means 9, and
By measuring the intensity distribution of the line 7, X-ray fluorescence analysis can be performed over a wide wavelength range without interlocking the spectroscopic element 6 and the detection means 8 with the sample 1. Note that the order of measurement is not limited to the order described above, for example,
It may be performed from the side of the heavy element having a short wavelength. The selection of the spectroscopic elements 6A, 6B,... May be performed by the operator by directly operating the motor 9b of the selection means 9, but may be automatically and continuously performed through control means such as a computer. Can also.

According to the apparatus of this embodiment, the spectral element 6
Are selectively located at predetermined positions with respect to the sample 1, and the spectroscopic element 6 and the detecting means 8 are not linked to the sample 1, so that a highly accurate measurement can be performed with a simple configuration. In addition, since the sample 1 and the spectroscopic element 6A, and the spectroscopic element 6A and the detection means 8 can be sufficiently close to each other, divergence and attenuation of the fluorescent X-rays 7 incident on the detection means 8 are suppressed, and sufficient sensitivity and high sensitivity are obtained. Can be measured. In particular, for example, a diameter of 5μ
In the case of using a very thin primary X-ray 3 such as SR light focused by an m collimator to analyze a minute part of the sample 1, high accuracy and sensitivity are required. The effect is large, and S / S
The N ratio improved.

[0018]

As described above, according to the present invention, high-precision and high-sensitivity measurement can be performed with a simple structure in X-ray fluorescence analysis.

[Brief description of the drawings]

FIG. 1 is a plan view showing an X-ray fluorescence analyzer according to one embodiment of the present invention.

FIG. 2 is a front view showing a conventional wavelength dispersive X-ray fluorescence spectrometer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... sample, 2 ... sample stage, 3 ... primary X-ray, 5 ... fluorescent X-ray generated from the sample, 6 ... spectral element, 7 ... spectral X-ray
Line, 8 ... Position resolution detecting means, 9 ... Selecting means.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Takashi Shoji, 14-8, Akaoji-machi, Takatsuki-shi, Osaka Prefecture Inside Rigaku Denki Kogyo Co., Ltd. (72) Eiji Yamada 14-8, Akaoji-cho, Takatsuki-shi, Osaka Science Denki Kogyo Co., Ltd.

Claims (2)

[Claims] 1. A sample stage on which a sample to be irradiated with primary X-rays is fixed, a plurality of spectroscopic elements having different lattice spacings, and the spectroscopic element is selectively positioned at a predetermined position with respect to the sample. Selecting means for dispersing the fluorescent X-rays generated from the sample, and fixing the fluorescent X-rays
An X-ray fluorescence analyzer comprising: a position resolution detector for measuring the intensity distribution of a line. 2. A method of irradiating a sample with primary X-rays, selectively arranging a plurality of spectroscopic elements having different lattice spacings at predetermined positions with respect to the sample, and obtaining fluorescent X-rays generated from the sample.
An X-ray fluorescence analysis method, wherein the X-rays are disperse | distributed and the intensity distribution of the disperse | distributed X-ray fluorescence is measured by the detection means which has fixed positional resolution with respect to the said predetermined position.