JPH06186015A - Analyzing method utilizing compton scattering beam, its device and monochrome apparatus for compton scattering beam - Google Patents

Abstract

PURPOSE:To improve the accuracy of analysis by setting up a scattering angle to a fixed angle, and inserting a filter containing an element having an absorbing end between the wavelength of radiation incident on a test piece and the wavelength of Compton scattering beam into the optical path of the scattering beam. CONSTITUTION:When radiation B1 is irradiated onto the surface of the coating film 14 of a measured test piece 10, a scattering beam and a fluorescent X-beam are generated from the test piece 10. In this case, a scattering angle phi is set up so that an element having the wavelength lambdak of a K absorbing end may be found between the wavelength lambdas (wavelength lambdas of Thomson scattering beam B,) of the radiation B1 and the wavelength lambdac of Compton scattering beam Bc. For instance, when the angle phi is set up to be 140 deg., and Mo-Kalpha beam is used as the radiation B1, a Y-element is an element having the wavelength lambdak. In this case, a scattering beam Bs is mostly or wholly absorbed by inserting a filter 32 having the Y-element as a main component into the optical path of the scattering beam Bc, to pass the scattering beam Bc and the fluorescent X-beam for making them enter a detector 3c. Thus the damping of strength of the scattering beam Bc becomes smaller (to about 1/10), and the accuracy of analysis can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analysis method and an analysis device using Compton scattered rays, and a monochromator.
The present invention relates to a method and an apparatus for obtaining monochromatic Compton scattered rays from scattered rays.

[0002]

2. Description of the Related Art Compton scattered radiation is a kind of scattered radiation,
Traditionally used for analysis. For example, a sample such as a color steel plate having a coating film on a base substrate is irradiated with radiation such as γ-rays, and the adhesion amount of the coating film is determined based on the intensity of Compton scattered rays from the sample that receives this radiation. A method for measuring is known (for example, Japanese Examined Patent Publication Sho 63-19).
(See Japanese Patent Application Laid-Open No. 004-41810).
Here, since the scattered rays include Thomson scattered rays in addition to Compton scattered rays, it is necessary to obtain Compton scattered rays that are monochromatic from the scattered rays. Conventionally, a dispersive crystal has been used as the method for monochromatization.

[0003]

However, when the monochromatization is performed using a dispersive crystal, the intensity of the Compton scattered ray obtained is attenuated to, for example, about 1/1000, so that the statistical error due to electrical noise becomes large, This leads to a decrease in analysis accuracy. The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a monochromator capable of obtaining Compton scattered rays with high intensity, and to provide an analysis method and an analysis device capable of improving analysis accuracy. And

[0004]

In order to achieve the above object, the analysis method of the present invention sets the scattering angle to a predetermined angle so that the wavelength of the radiation incident on the sample and the Compton scattering generated at the above scattering angle. An element having an absorption edge with respect to the wavelength of the line is found, and a filter containing this element is inserted into the optical path of the above scattering angle to make the Compton scattering line monochromatic.
On the other hand, the analyzer and the monochromator of the present invention are those in which a filter is arranged in the optical path of the scattering angle set to a predetermined angle,
This filter contains an element having an absorption edge between the wavelength of the radiation (the wavelength of the Thomson scattered ray) and the wavelength of the Compton scattered ray generated at the above scattering angle.

[0005]

Next, the principle of the present invention will be described. When the radiation B1 collides with the atom A as shown in FIG.
In addition to the fluorescent X-rays peculiar to the element, Compton scattered radiation B _C and Thomson scattered radiation B _S are generated. The wavelengths of these scattered rays B _C and B _S have a relationship as shown in the following expression (1). Δλ = λ _C −λ _S = 0.0243 (1-COSφ) (1) where λ _S : wavelength of Thomson scattered ray (10 ⁻¹⁰ m) λ _C : wavelength of Compton scattered ray (10 ⁻¹⁰ m) φ: Scattering angle (angle when the traveling direction of particles is bent by collision)

As can be seen from the above equation (1), the wavelength difference Δλ between the Thomson scattered ray B _S and the Compton scattered ray B _C.
Is generally small, and conventionally, a monochromatic Compton scattered ray B _C was obtained by using a dispersive crystal with high resolution.

However, as can be seen from the above equation (1), if the scattering angle φ is set large, the wavelength difference Δλ becomes large.
Accordingly, the inventors, by setting the scattering angle φ to a large predetermined angle, K between the wavelength lambda _S Thomson scattered radiation B _S as shown in FIG. 3, the wavelength lambda _C Compton scattered radiation B _C The inventors have completed the invention by discovering that an element having an absorption edge λ _K can be found.

[0008] According to the present invention, rather than analyzing crystal, using a filter, and monochromatic (attenuated Thomson scattered radiation) since Compton scattered radiation B _C is obtained, the intensity decay of the Compton scattered radiation B _C It will be an extremely small value of about 1/10. Therefore, Compton scattered ray B _{C with} high intensity
Therefore, the statistical error is reduced and the analysis accuracy is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the sample 10 to be measured has a coating film 14 on a base substrate 11. This measured sample 1
0 moves continuously, for example. An adhesion amount measuring device 20 is provided at an arbitrary position where the measured sample 10 is moving.

The adhesion amount measuring device 20 includes a radiation source 21 and
The measuring device 30 and the calculator 23 are provided. Radiation source 2
1 is radiation B1 on the surface of the coating film 14 of the sample 10 to be measured.
For example, an X-ray tube or a radioactive isotope of americium is used. The measuring device 30 includes a parallel optical system 31, a filter 32, a detector 33 and a wave height analyzer 3.
4 for measuring the intensity of Compton scattered radiation B _C from the sample 10 to be measured which has received the radiation B1.

The filter 32 is a Compton scattered ray B generated at a scattering angle φ set at a predetermined angle described later.
It is inserted in the optical path of _C. The scattering angle phi, as shown in FIG. 3, for example, γ-rays generated from americium 241 and (radiation) wavelengths B1 lambda _S (wavelength lambda _S Thomson scattered radiation B _S), the scattering angle is set to a predetermined angle phi At the K absorption edge λ between the wavelength λ _C of the Compton scattered ray B _C
Set so that the element with _K can be found.

Now, when the scattering angle φ is set to 140 °,
The wavelength λ _C of the Compton scattered ray B _C is as shown in Table 1 below, and the wavelength of the radiation (wavelength of the Thomson scattered ray) λ
Elements constituting the filter 32 (FIG. 1) are determined based on _S and the wavelength λ _C of the Compton scattered ray B _C. For example, when Mo-Kα rays are used as the radiation B1 for excitation (FIG. 1), the filter 32 (FIG. 1) containing yttrium as a main component is used.

[0013]

[Table 1]

The scattering angle φ is generally 100 ° to 160 °.
It is set to a degree. The reason is that if the scattering angle φ is smaller than 100 °, Δλ = λ _C −λ _S becomes too small. On the other hand, if the scattering angle φ is larger than 160 °, the intensity of the Compton scattered ray B _C is increased. This is because the decrease becomes remarkable.

The filter 32 allows Compton scattered rays B _C and fluorescent X-rays of the scattered rays and fluorescent X-rays scattered from the sample to be measured 10 to pass therethrough, and Thomson scattered rays B _S.
Is set to a thickness that absorbs most or all of the.
The Compton scattered ray B _{C that} has passed through the filter 32 enters the detector 33.

The detector 33 detects the incident Compton scattered ray B _C and outputs it as the detection output e1 to the wave height analyzer 3
Output to 4. The wave height analyzer 34 counts only the pulses having a predetermined wave height corresponding to the energy of the Compton scattered ray B _C from the detection output e1 and outputs the intensity of the Compton scattered ray B _{C to} the calculator 23 as the measurement signal c. The calculator 23 receives the measurement signal c and receives the Compton scattered radiation B
The adhesion amount of the coating film 14 is calculated by a known method based on the strength of _C. When there is a plated film under the coating film 14, the fluorescent X-ray corresponding to the intensity of the Compton scattered ray B _C generated from this plated film is measured, and correction such as subtraction is performed.

[0017] In the above structure, the wavelength lambda _S Thomson scattered radiation B _S in FIG. 3, the wavelength of the Compton scattered X-ray B _C lambda _C
Fig. 1 mainly containing an element having a K absorption edge λ _K between
Since the intensity of the Thomson scattered ray B _S is attenuated by using the filter 32 of No. 2, the intensity attenuation of the Compton scattered ray B _C becomes significantly smaller than that in the case of using the dispersive crystal. Therefore, the Compton scattered ray B _C having a high intensity can be obtained, and the analysis accuracy is improved.

Further, since the filter 32 is generally cheaper than the dispersive crystal, the cost of the device can be reduced.

In the above embodiments, the color steel plate was described, but the present invention can be applied to the analysis of organic substances other than the color steel plate. Further, the present invention is
It applies not only as such an analysis method and device but also to a monochromator.

[0020]

As described above, according to the present invention, since the Thomson scattered ray is attenuated by using the filter instead of the dispersive crystal, the intensity of the obtained Compton scattered ray becomes remarkably larger than that of the conventional method, and the analysis is performed. The accuracy can be improved and the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an analyzer according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a generation state of Compton scattered rays.

FIG. 3 is a characteristic diagram showing the relationship between the wavelength and intensity of scattered radiation.

[Explanation of symbols]

10 ... Sample, 21 ... Radiation source, 32 ... Filter, B1 ...
Radiation, B _C ... Compton scattered ray, B _S ... Thomson scattered ray, φ ... Scattered angle.

Claims (3)

[Claims] 1. An analysis method using Compton scattered rays, which comprises irradiating a sample with radiation and analyzing the sample based on the intensity of the Compton scattered rays from the sample that has received the radiation, wherein the scattering angle is a predetermined angle. By setting, we find an element that has an absorption edge between the wavelength of the radiation and the wavelength of the Compton scattering line generated at the scattering angle, and insert a filter containing this element into the optical path of the Compton scattering line generated at the scattering angle. An analysis method using Compton scattered rays, which is characterized in that the Compton scattered rays are monochromaticized. 2. An analyzer using Compton scattered rays, which irradiates a sample with radiation and analyzes the sample based on the intensity of the Compton scattered rays from the sample that has received this radiation, is set at a predetermined angle. A filter is arranged in the optical path of the Compton scattered ray generated at the scattering angle, and the filter includes an element having an absorption edge between the wavelength of the radiation and the wavelength of the Compton scattered ray generated at the scattering angle. An analyzer using Compton scattered radiation, which is characterized in that 3. A Compton scatter ray monochromator for obtaining a Compton scatter ray obtained by monochromatic conversion from scattered rays, wherein a filter is arranged in the optical path of the Compton scatter ray generated at a scattering angle set to a predetermined angle, and this filter is provided in this filter. A monochromator for Compton scattered rays, which contains an element having an absorption edge between the wavelength of the Thomson scattered rays and the wavelength of the Compton scattered rays generated at the above scattering angle.