JP3411705B2 - X-ray analyzer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray analyzer capable of accurately measuring characteristic X-rays from an element to be measured generated from a sample and its background. It is. 2. Description of the Related Art For example, in a fluorescent X-ray analyzer, when it is desired to remove the influence of a background having a wavelength close to the characteristic X-ray from characteristic X-rays generated from an element contained in a sample, a conventional method has been proposed. By moving a single detector or spectral element by an angle corresponding to the difference between the two diffraction angles, the intensities of both are measured, and the intensity of the latter is subtracted from the intensity of the former. However, since the detector or the spectroscopic element is moved in the measurement of the intensity of both, it is difficult to secure mechanical accuracy, and accurate measurement cannot be performed. Therefore, the present applicant first separates the characteristic X-ray and its background with a single spectroscopic element, and focuses the light on two adjacent light receiving slits provided in front of a single detector. Then, by alternately opening the two light receiving slits, a device for measuring each without moving a detector or a spectroscopic element was proposed (Japanese Patent Application No. 6-292361).
issue). However, in the device according to the prior art, since only one curved spectral element is used, the element to be measured is a heavy element, and the characteristic X-ray and its background If the difference between the diffraction angles is less than 1 degree, it is possible to measure both intensities. However, if the element to be measured is an ultralight element such as nitrogen and the difference between the characteristic X-ray and its background is different. If it is about 10 degrees, these diffraction angles cannot be satisfied at the same time with a single spectroscopic element.
Both intensity measurements are not possible. The present invention has been made in view of the above-mentioned conventional problems. Even when an element to be measured generated from a sample is an ultra-light element such as nitrogen, a characteristic X-ray and its background can be detected by a detector. It is an object of the present invention to provide an X-ray analyzer that can accurately measure without moving a spectroscopic element or a spectroscopic element. In order to achieve the above object, an X-ray analyzer according to claim 1 is an X-ray analyzer for generating primary X-rays.
Source and secondary X generated from the sample irradiated with primary X-ray
A divergent slit member having a divergent slit for passing a line, two curved spectral elements arranged in parallel with each other in a divergent secondary X-ray path passing through the divergent slit member, and the two curved spectral elements. A light-receiving slit device for passing the characteristic X-ray from the element to be measured and its background diffracted respectively, and a single detector to which the characteristic X-ray and the background passed through the light-receiving slit device are incident. The light receiving slit device,
A light-receiving slit member having two light-receiving slits through which the characteristic X-ray and one of the background thereof pass, respectively, and selectively opening one of the two light-receiving slits, Selective opening means for making any of the background incident on the detector. In the X-ray analyzer according to the first aspect, the characteristic X-rays from the element to be measured, which are generated from the sample, and the background thereof are determined by using two curved spectroscopic elements respectively corresponding to the characteristic X-rays. Spectroscopy, focusing two light receiving slits adjacent to each other in front of a single detector,
Since the two light receiving slits are opened alternately, even if the element to be measured is an ultralight element such as nitrogen, accurate measurement can be performed without moving the detector or the spectroscopic element. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the X-ray analyzer of the embodiment includes an X-ray source 1 that generates a primary X-ray 2 and a sample 2 that is attached to a sample table 19 and is generated from a sample 3 irradiated with the primary X-ray 2 A divergent slit member 4 having divergent slits P ₁ and P ₂ for passing the next X-rays 5 and 6 is provided. Further, two secondary X-rays 5 passing through the diverging slits P ₁ and P ₂ ,
The X-ray spectroscope 20 is provided in the passage 6. This X-ray spectrometer 20 is a two-line ₂ that has passed through the divergence slits P ₁ and P 2.
In the respective passages of the next X-rays 5, 6, the lattice planes 11, 1
2 are arranged in parallel, and the secondary X-rays 5 and 6 are incident at incident angles θ ₁ and θ ₂ , respectively, and diffract the characteristic X-ray 14 from the element to be measured and the background 15 thereof. Curved first and second spectral elements 7 and 8 made of an artificial lattice. The X-ray analyzer further includes a light receiving slit device 16 for passing the characteristic X-ray 14 diffracted by the curved spectroscopic elements 7 and 8 and the background 15 thereof, and a characteristic X-ray for passing the light receiving slit device 16. It comprises a single detector 17 on which a line 14 and its background 15 are incident. Here, the light receiving slit device 16 includes a light receiving slit member 9 having two light receiving slits Q ₁ and Q ₂ through which the characteristic X-ray 14 and its background 15 pass, respectively, and two light receiving slits Q _1. , Q ₂ is selectively opened, and a moving slit member 10 having a moving slit Q ₃ opened to make either the characteristic X-ray 14 or its background 15 incident on the detector 17. . The incident angle θ ₂ is larger than the incident angle θ ₁ , and the lattice plane distance d ₁ of the first spectral element 7 is set.
And the lattice plane distance d ₂ of the second spectral element 8 have the following relationship. First, from the Bragg condition, assuming that the wavelengths of the characteristic X-ray 14 to be split and the background 15 thereof are λ ₁ and λ ₂ , respectively, 2d ₁ × sin θ ₁ = λ ₁ ( ₂ ) 2d ₂ × sin θ ₂ = in λ ₂ ... ₍₂₎ where, lambda ₂ is in the lambda ₁ and the diffraction angle there is a difference of about 10 degrees 1 degree, it is known from lambda _1. The angle between the two secondary X-rays 5 and 6 that have passed through the divergence slits P ₁ and P ₂ is φ, and the incident points of the secondary X-rays 5 and 6 on the spectroscopic elements 7 and 8, respectively. That is, considering the normal 13 to the lattice planes 11 and 12 passing through the points A and B at the center of the lower surface of each of the spectral elements 7 and 8, from the geometrical relationship, θ ₁ = θ ₂ −φ (3) From the above relationship, the lattice spacing d ₁ and the incident angle θ ₁ in the first spectral element 7 and the lattice spacing d ₂ and the incident angle θ ₂ in the second spectral element 8 can be appropriately set as follows. Temporary lattice spacing d ₁
If the first spectral element 7 is adopted, the first spectral element 7
Is the incident angle θ _{1 at} which the characteristic X-ray 1
From the wavelength λ _{1 of} 4, the formula (1) is determined by the following formula (4) which is a modification of the formula (1). θ ₁ = sin ⁻¹ (λ ₁ / 2d ₁ ) (4) When the incident angle θ _{1 on} the first spectral element 7 is determined,
The incident angle θ ₂ in the second spectral element 8 can be determined by determining the angle φ between the two secondary X-rays 5 and 6 passing through the divergent slits P ₁ and P _2, and 5) It is determined by the equation. θ ₂ = θ ₁ + φ (5) When the incident angle θ _{2 on} the second spectral element 8 is determined, the lattice plane distance d ₂ of the second spectral element 8 becomes
It is determined by the following equation (6) obtained by modifying the equation (2). _{d 2 = λ 2/2 sinθ} 2 ... (6) where the lattice spacing d ₁ of the first spectral element 7 lattice spacing d ₂ of the second spectral element 8, from equation (1) to (6) As long as it satisfies, they are not necessarily different and may be the same. In this embodiment, since the curved spectral elements 7 and 8 are used, for example, one of the secondary X-rays 5 passing through the divergent slit P ₁ is incident on the lower surface of the first spectral element 7. Irrespective of this, even at the point A at the center of the lower surface, the light is similarly diffracted at the incident angle θ ₁ . That is, in FIG. 1, for simplicity, while passing through the divergence slit P ₁ of 2
For the next X-ray 5, a point A at the center of the lower surface of the first spectral element 7
Although the secondary X-rays 5 incident on the first X-ray are illustrated as representative examples, they are actually secondary X-rays that spread from the divergence slit P ₁ to the entire lower surface of the first spectral element 7. Regarding the diffracted characteristic X-rays 14, the first
Although illustrated characteristic X-rays 14 entering from the center of the lower surface of the point A to the receiving slit to Q ₁ spectral device 7 as a representative example, in fact, the entire lower surface of the first spectral element 7, the receiving slit Q ₁
Is a characteristic X-ray focused on This situation is the same for the other secondary X-ray 6 incident on the second spectral element 8 and the diffracted background 15. Next, the operation of the first embodiment will be described. Now, it is assumed that the intensity I of the characteristic X-ray of a certain element contained in the sample 3 is measured using this apparatus. Primary X-rays 2 generated from the X-ray source 1 is irradiated to the sample 3, the secondary X-rays 5 emitted from the sample 3 is diverged in a state in which the divergence angle through the divergence slit P ₁ is controlled, spectroscopic element 7 is incident on split into the desired characteristic X-ray 14, focused by the light-receiving slit Q _1, and passes through the moving slit Q _3, is incident on the detector 17, the intensity I _m is measured. This measured intensity _Im
The, in addition to the fact that attempts to find the characteristic X-ray of the true intensity I, it contains the background intensity I _b. On the other hand, a secondary X-ray 15 having a background having a different diffraction angle from the characteristic X-ray 14 by about 1 to 10 degrees is generated from the sample 3 similarly to the characteristic X-ray 14, and the divergent slit P ₂ diverges in a state where the divergence angle is controlled, is split by the spectroscopic element 8, and is focused by the light receiving slit Q _2.
7 is blocked. Here, the moving slit Q
₃ move the moving slit member 10 to come behind the receiving slit Q _2, the intensity I _b background 15 is incident on the detector 17 is measured, characteristic X-ray 1
4 is shut off. From the measured intensity I _m of the characteristic X-ray 14, by subtracting the background intensity I _b, the true intensity I of the characteristic X-rays are obtained. Here, the reason why the single detector 17 is used is that two detectors 17 are used, each having the characteristic X.
When measuring the measured intensity I _m of the lines 14 and background intensity I _b, because not required the true intensity I accurate characteristic X-rays by the difference between the detection characteristics of the detector. As described above, in the X-ray analyzer of this embodiment, the characteristic X-rays 14 from the element to be measured and the background 15 thereof generated from the sample 3 correspond to the two curved spectroscopic elements corresponding to the respective elements. 7,8 spectrally using, by bear two respective focal point receiving slit Q _1, Q ₂ of which is provided adjacent to the front of a single detector 17, the two light-receiving slit Q _1, Q ₂ Are alternately opened, so that even if the element to be measured is an ultralight element such as nitrogen, accurate measurement can be performed without moving the detector 17 or the spectroscopic elements 7 and 8. In this embodiment, the characteristic X-rays 14 are formed by the first spectral element 7 in which the grating surfaces 11 and 12 are parallel and the secondary X-rays 5 are incident at a smaller incident angle θ ₁ in FIG. The background 15 is diffracted by the second spectral element 8 on which the secondary X-ray 6 is incident at a larger incident angle θ ₂ , but the reverse is also possible, and the grating surfaces 11 and 12 need to be parallel. Absent. Further, for example, the characteristic X-rays 14 emitted from a point A at the center of the lower surface of the first spectral element 7 are
Then enters the _two, may be background 15 exiting from the point B of the center of the lower surface of the second spectral element 8, arranged to be incident on the light-receiving slit to Q ₁ lower. Furthermore, only one diverging slit P ₁ , P ₂ can be provided. Primary X
The incident point of the line 2 on the sample 3 is actually distributed not only at one point O but also on the surface of the sample 3, and secondary X-rays generated from different incident points are provided on the diverging slit member 4. This is because two secondary X-rays 5 and 6 can be incident on the spectral elements 7 and 8, respectively, as in the present embodiment by passing through a single diverging slit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing an embodiment of the present invention. [Description of Signs] 1 ... X-ray source, 2 ... Primary X-ray, 3 ... Sample, 4 ... Diverging slit member, 5, 6 ... Secondary X-ray generated from sample, 7, 8 ...
Spectral element, 9: light receiving slit member, 10: selective opening means, 14: characteristic X-ray, 15: background, 16 ...
Receiving slit device 17 ... detector, P _1, P ₂ ... divergence slit, Q _1, Q ₂ ... receiving slit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-82149 (JP, A) JP-B-51-5316 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 23/223

Claims (1)

(57) [Claim 1] An divergence having an X-ray source for generating primary X-rays and a divergence slit for passing secondary X-rays generated from a sample irradiated with the primary X-rays A slit member, two curved spectral elements arranged in parallel with each other in the path of the divergent secondary X-ray that has passed through the divergent slit member, and an element to be measured diffracted by each of the two curved spectral elements. A light receiving slit device that passes the characteristic X-rays and the background thereof, and a single detector that receives the characteristic X-rays and the background that have passed through the light receiving slit device. A light receiving slit member having two light receiving slits for passing the characteristic X-rays and one or the other of the background thereof, respectively, and selectively opening one of the two light receiving slits; Serial characteristic X-ray and X-ray analysis apparatus having a selection opening means to be incident on the detector either with its background.