JPH08110312A - Radiation spectroscope - Google Patents

Abstract

PURPOSE: To provide a radiation spectroscope wherein, even if secondary radiation generated from a sample is long wavelength, intensity of the secondary radiation which is made incident on a radiation detector is enough, so that, accurate analysis is possible. CONSTITUTION: Multiple spectral elements 7 and 8, spacing of lattice planes different each other, which are assigned parallel to each other on the pathes of secondary radiation 5 and 6 generated by a sample 3 irradiated with primary radiation 2 from a radiation source 1, are provided, and, these spectral elements 7 and 8 are so set as to diffract the secondary radiation 14 and 15 of the same wave length, for them to enter into a single radiation detector 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation spectroscope that effectively focuses radiation emitted from a sample.

[0002]

2. Description of the Related Art For example, in a conventional X-ray fluorescence analyzer, a sample is irradiated with primary X-rays and an appropriate X-ray is emitted from the sample in accordance with the wavelength of a specific fluorescent X-ray. A single spectroscopic element having a lattice spacing is installed at an appropriate spectroscopic angle, and the fluorescent X-rays are dispersed and made incident on the X-ray detector.

[0003]

However, in the above-mentioned conventional technique, particularly in the case of long wavelength fluorescent X-rays generated from light elements, the intensity of the fluorescent X-rays incident on the X-ray detector is not sufficient, and the accuracy is high. Analysis may be difficult.

The present invention has been made in view of the above-mentioned conventional problems. Even if the secondary radiation generated from the sample has a long wavelength, the intensity of the secondary radiation incident on the radiation detector is sufficient. It is an object of the present invention to provide a radiation spectrometer that enables accurate analysis.

[0005]

In order to achieve the above object, a spectroscope according to claim 1 is arranged in parallel with each other in a path of secondary radiation generated from a sample irradiated with primary radiation generated from a radiation source. A radiation spectroscope provided with a plurality of spectroscopic elements having different lattice plane intervals, and the spectroscopic elements are set to diffract secondary radiation of the same wavelength to be incident on a single radiation detector. Is.

[0006]

In the spectroscope according to the first aspect of the present invention, the secondary radiation of the same wavelength generated from the sample is diffracted by a plurality of spectroscopic elements having different lattice plane intervals, and is incident on a single radiation detector. The intensity of the secondary radiation incident on the radiation detector is increased as compared with the case where the light is dispersed by a single dispersive element. As a result, the sensitivity is improved, and accurate analysis is possible even if the secondary radiation has a long wavelength.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First, the first embodiment will be described. In FIG. 1, the primary X-ray 2 generated from the X-ray source 1 is irradiated on the sample 3, and the secondary X-ray generated from the sample 3 is narrowed down by the divergence slit 4. Here, the first X-ray spectrometer
The radiation spectroscope 20 of the embodiment is arranged such that the lattice planes 11 and 12 are parallel to each other in the passages of the two secondary X-rays 5 and 6 that have passed through the divergence slit 4.
Next X-rays 5 and 6 are incident at incident angles θ ₁ and θ ₂ , respectively, and the curved first and second spectroscopic elements 7 and 8 made of an artificial lattice that disperse the fluorescent X-rays 14 and 15 having the same specific wavelength.
It has. The X-rays other than the fluorescent X-rays 14 and 15 are excluded by the light receiving slit 9, and the fluorescent X-rays 14 and 15 that have passed through the light receiving slit 9 are the single X-ray detector 10.
Is incident on. As the curved first and second spectroscopic elements 7 and 8, for example, a Johan type, a Johansson type, or a log spiral type can be used.

[0008] Here, the incident angle theta ₂ is made larger than the incident angle theta _1, the phase lattice spacing d ₁ of the different first spectral element 7 and the lattice spacing d ₂ of the second spectral element 8, below There is such a relationship. First, from the Bragg conditions, if the wavelength of the fluorescent X-rays 14 and 15 to be dispersed is λ, then 2d ₁ × sin θ ₁ = λ (1) 2d ₂ × sin θ ₂ = λ (2) 2 secondary X-rays 5, 6 that passed 4
Is defined as φ, and the respective incident points of the secondary X-rays 5 and 6 on the spectroscopic elements 7 and 8, that is, the spectroscopic elements 7 and 8
Lattice planes 11 and 12 passing through the points A and B at the center of each bottom surface
Considering the normal line 13 to, from the geometrical relation, θ ₁ = θ ₂ −φ (3)

From the above relationships, the lattice plane spacing d ₁ and the incident angle θ ₁ in the first spectroscopic element 7 and the lattice plane spacing d ₂ and the incident angle θ ₂ in the second spectroscopic element 8 are appropriately set as follows. it can. If there is a lattice spacing d ₁
If the first spectroscopic element 7 is adopted, the first spectroscopic element 7
The incident angle θ _{1 at} is the fluorescent X-ray 1
The wavelength λ of 4 is determined by the following equation (4) which is a modification of the equation (1). θ ₁ = sin ⁻¹ (λ / 2d ₁ ) ... (4) When the incident angle θ ₁ in the first spectroscopic element 7 is determined,
The incident angle θ ₂ in the second spectroscopic element 8 can be calculated by the following formula (5), which is a modification of the formula (3), if the angle φ formed by the two secondary X-rays 5 and 6 that have passed through the divergence slit 4 is determined. It is determined. θ ₂ = θ ₁ + φ (5) When the incident angle θ ₂ in the second spectroscopic element 8 is determined,
The lattice spacing d ₂ of the second spectroscopic element 8 is determined by the following equation (6) which is a modification of the equation (2). d ₂ = λ / 2 sin θ ₂ (6)

Since the curved spectroscopic elements 7 and 8 are used in the first embodiment, for example, one secondary X-ray 5 which has passed through the divergence slit 4 is incident on the lower surface of the first spectroscopic element 7. Regardless of the above, even if it is not the point A at the center of the lower surface, the light is diffracted at the incident angle θ ₁ . That is, in FIG.
For simplicity, one of the secondary X-rays 5 that has passed through the divergence slit 4 is illustrated as a representative example of the secondary X-ray 5 that is incident on the point A at the center of the lower surface of the first spectroscopic element 7. Two
The next X-ray 5 is a secondary X-ray that spreads from the point P ₁ that has passed through the divergence slit 4 to the entire lower surface of the first spectroscopic element 7.

Regarding the one diffracted fluorescent X-ray 14 as well, the fluorescent X-ray 14 incident on the incident point Q ₁ to the light receiving slit 9 from the point A at the center of the lower surface of the first spectroscopic element 7 is shown as a representative example. Actually, the fluorescent X-rays are focused from the entire lower surface of the first spectroscopic element 7 to the incident point Q ₁ on the light receiving slit 9. This situation is the same for the other secondary X-rays 5 incident on the second spectroscopic element 8 and the diffracted fluorescent X-rays 15.

Next, the operation of the first embodiment will be described. The primary X-ray 2 generated from the X-ray source 1 is applied to the sample 3, and the secondary X-ray generated from the sample 3 is narrowed down to two secondary X-rays 5 and 6 by the divergence slit 4, and this divergence slit The two secondary X-rays 5 and 6 that have passed through 4 are incident on the first and second spectroscopic elements 7 and 8 of the X-ray spectrometer 20, respectively,
The fluorescent X-rays 14 and 15 of a desired identical wavelength are separated into each, pass through the light-receiving slit 9, and pass through a single X-ray detector 10.
Is incident on. As a result, the intensity of the fluorescent X-rays incident on the X-ray detector 10 becomes high.

Here, in the X-ray spectroscope 20, the first spectroscopic element 7 is made large to be long in the left-right direction in FIG.
The secondary X-rays 6 incident on the spectroscopic element 8 are also incident on the first spectroscopic element 7, and the fluorescent X-rays having the same intensity as in the first embodiment are spectrally separated only by the first spectroscopic element 7. X-ray detector 1
It is also possible to make it enter 0. However, it is difficult to manufacture such a large curved spectroscopic element, and even if it is possible to manufacture the spectroscopic element, the condensing points of the X-rays that are diffracted by entering the central portion and the end portion of the diffraction surface of the spectroscopic element are It is inevitable that the X-ray detector 10 deviates, and the focusing property on the X-ray detector 10 is poor. In contrast,
The present invention does not have such drawbacks.

By the way, in general, the intensity of the fluorescent X-rays which are split by the spectroscopic element and are incident on the X-ray detector becomes weaker as the optical path of the X-ray becomes longer and as the lattice plane spacing of the spectroscopic element becomes narrower. . In the first embodiment, the fluorescent X-rays 15 that are split by the second spectroscopic element 8 and enter the X-ray detector 10 are compared with the fluorescent X-rays 15 that are split by the first spectroscopic element 7 in the sample 3
Since the optical path from the light emitted from the light source to the X-ray detector 10 is long and the light is dispersed by the second light-splitting element 8 having a small lattice spacing d ₂ , the fluorescent light X incident on the X-ray detector 10 is separated. The line strength becomes weak.

However, if the fluorescent X-rays 14 and 15 of the same wavelength, which are separated by the first and second spectroscopic elements 7 and 8 are combined and incident on a single X-ray detector 10, a single first spectroscopic spectrum is obtained. Intensity of 1.5 times or more of the intensity obtained by only the fluorescent X-rays 14 dispersed by the element 7 can be obtained. As a result, 2 generated from the sample 3
Even if the next X-rays 5 and 6 have a long wavelength, the intensity of the fluorescent X-rays 14 and 15 incident on the X-ray detector 10 is sufficient and accurate analysis can be performed.

Next, a second embodiment will be described. First
In the embodiment, the first and second spectroscopic elements 7 and 8 are arranged such that their lattice planes 11 and 12 are parallel, but the present invention is not limited to the lattice planes 11 and 12 being parallel. . For example, in the second embodiment shown in FIG. 2, when the light receiving slit 29 has only one gap Q ₃ , the primary X-ray 2
Straight line 5 connecting the incident point O to the sample 3 and the gap P ₃ below the divergence slit 24, the gap P ₃ and the light receiving slit 2
The intersection D of the line segment 31 connecting the gap Q _{3 of} 9 with the vertical bisector 23 is defined as the center point of the lower surface of the first spectroscopic element 27, and the incident angle θ ₃ of the first spectroscopic element 27 is equal to the lattice plane 21. The vertical 2
It is determined by setting the line equally to the bisector 23.

Similarly, a straight line 6 connecting the point O where the primary X-ray 2 enters the sample 3 and the gap P _{4 above the} divergence slit 24.
And the intersection point E of the vertical bisector 25 of the line segment 32 connecting the gap P ₄ and the gap Q ₃ of the light receiving slit 29, the arrangement of the second spectroscopic element 28 and the incident angle θ ₄ are determined. To be Lattice plane spacing d of the first and second spectroscopic elements 27 and 28
₃ , d ₄ can be obtained from the equation (6). The X-ray spectroscope 30 configured by this has the same operation as the X-ray spectroscope 20 of the first embodiment.

In addition to the first and second embodiments, for example, FIG.
In, the divergence slit 4 may have only one gap. The incident points of the primary X-rays 2 on the sample 3 are actually distributed not only at one point O but also on the surface of the sample 3, so that the secondary X-rays generated from different incident points are emitted from the divergence slit 4. This is because a plurality of secondary X-rays 5 and 6 can be made incident on a plurality of spectroscopic elements 7 and 8, respectively, by passing through a single gap, as in the first embodiment. In addition, for example, in FIG. 1, the lattice planes 11 and 12 are not parallel, and the fluorescent X-ray 14 emitted from the point A at the center of the lower surface of the first spectroscopic element 7.
Enters the gap Q ₂ on the upper side of the light receiving slit 9 and the fluorescent X-rays 15 emitted from the point B at the center of the lower surface of the second spectroscopic element 8 enters the gap Q ₁ on the lower side of the light receiving slit 9. It can also be arranged.

In the first embodiment, for example, two curved spectroscopic elements 7 and 8 having different lattice spacings d ₁ and d ₂ are used, but the spectroscopic element used in the present invention is not limited to the curved one. Alternatively, two flat plate dispersive elements having different lattice spacings may be used. In this case, solar slits are used as the divergence slit 4 and the light-receiving slit 9, and the light is incident on the spectroscopic elements 7 and 8 or the X-ray detector 10 in the state of parallel light. Further, the spectroscopic element used in the present invention is not limited to two,
It is also possible to use a plurality of three or more spectroscopic elements.

Further, in the first and second embodiments, the radiation to be dispersed is X-rays, but the radiation that can be dispersed in the present invention is not limited to X-rays, and radiation other than X-rays, such as synchrotron radiation, etc. The present invention can also be used for

[Brief description of drawings]

FIG. 1 is a side view of a first embodiment of the present invention.

FIG. 2 is a side view of the second embodiment of the present invention.

[Explanation of symbols]

1 ... Radiation source, 2 ... Primary radiation, 3 ... Sample, 5, 6 ... Secondary radiation generated from sample 7, 8 ... Spectroscopic element, 10 ... Radiation detector, 14, 15 ... Diffracted 2 of the same wavelength Next radiation, 20 ... Radiation spectrometer.

Claims (1)

[Claims] 1. A spectroscopic element comprising a plurality of spectroscopic elements which are arranged in parallel to each other in a passage of secondary radiation generated from a sample irradiated with primary radiation generated from a radiation source and have different lattice plane intervals. Is a radiation spectroscope set to diffract secondary radiation of the same wavelength and make it incident on a single radiation detector.