JPH0353577B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is used to analyze the material structure of a sample by utilizing small angle scattering of X-rays when the sample is irradiated with X-rays. The present invention relates to an X-ray small-angle scattering measuring device.

(Prior art) In general, when analyzing material structures of about 10 nm to 200 nm, such as colloidal particle size and long-period structure of fibers, small-angle X-ray scattering measurement equipment that uses small-angle scattering of X-rays is used. used.

In this measurement device, where ε ₀ is the minimum measurable scattering angle of the sample, λ is the wavelength of the X-ray, and d is the lattice spacing or period of the sample, the following relationship exists: d=λ/ε ₀ ...(1) .

Therefore, from the relationship in equation (1), in order to determine d, it is necessary to select λ in advance, and for this reason, it is necessary to make the X-rays monochromatic.
Furthermore, in equation (1), in order to analyze a case where the lattice spacing d is large, it is necessary to measure a small ε ₀ . In order to measure a small value of ε ₀ and improve the resolution of d, it is necessary to increase the parallelism of the X-rays incident on the sample as much as possible in advance, that is, to collimate the X-rays.

(Problem to be solved by the invention) In order to make X-rays monochromatic, it is possible to use a monochromator that uses single crystal reflection, but simply using a monochromator will reduce the X-ray intensity. The S/N ratio deteriorates. In addition, in order to collimate X-rays, it is possible to increase the distance between the slits placed between the X-ray source and the sample, but if the distance between the slits is increased in this way,
The overall size of the apparatus increases, resulting in inconveniences such as, for example, the goniometer provided in the existing X-ray diffraction apparatus cannot be used also for measuring small-angle X-ray scattering.

The present invention solves the above-mentioned problems, makes it possible to obtain scattered X-ray intensity and scattering angular resolution that can be put to practical use, downsizes the entire device, and has several advantages described below. An object of the present invention is to provide an X-ray small-angle scattering measurement device.

(Means for solving the problem) Therefore, the X-ray small-angle scattering measurement device of the present invention has the following features:
A first monochrome collimator is provided between the X-ray source and the sample to guide the X-rays from the X-ray source to the sample, and a first monochrome collimator is provided between the sample and the detector to direct the X-rays scattered by the sample to the detector. A second monochrome collimator is arranged to guide the light, and each of the first and second monochrome collimators is made of a single crystal whose crystal surface is notched and inclined at a predetermined angle with respect to the crystal lattice plane so as to provide asymmetric reflection. It is characterized by being arranged and configured such that the incident angle of the X-rays on the crystal surface is smaller than the reflection angle.

(Function) In the above configuration, X-rays from the X-ray source first enter the first monochrome collimator. This first monochromatic collimator is made of a single crystal whose crystal surface is notched at a predetermined angle with respect to the crystal lattice plane, and the incident angle of the X-rays on the crystal surface is smaller than the reflection angle. Because of this arrangement, incident X-rays are reflected asymmetrically, and at that time, they are monochromated and collimated. The sample is then irradiated with monochrome collimated X-rays. The X-rays scattered by the sample are incident on the second monochrome collimator. This second monochrome collimator selectively reflects only the scattered X-rays included in a predetermined angular range necessary for intensity measurement among the scattered X-rays. and,
The intensity of the selected scattered X-rays is detected by a detector.

(Example) FIG. 1 is a configuration diagram of an X-ray small-angle scattering measurement apparatus according to an example of the present invention. In the figure, reference numeral 21
is an X-ray source, and 22 is an X generated from the X-ray source 21.
23 is a sample, and 24 is a detector for detecting scattered X-rays from the sample 23.

S ₂₁ and S ₂₂ are first and second slits for regulating the divergence angle of the X-ray 22, and C ₁ is the X-ray from the X-ray source 21.
This is a first monochrome collimator that guides the line 22 to the sample 23. This first monochrome collimator C ₁ is
As shown in Figure 2, when the diffraction angle of X-rays with respect to the crystal lattice plane is θ _B , the crystal surface is inclined at a predetermined angle θ _B −θ ₀ with respect to the crystal lattice plane so that asymmetric reflection occurs. Both _{parts C 11} , The former crystal part C ₁₁ is formed by cutting out C 12 and has a so-called channel cut shape, and the former crystal part C ₁₁ is formed so that the incident angle θ ₀ of the X-ray 22 on the crystal surface is smaller than its reflection angle θ h. arranged and configured.

S ₂₃ and S ₂₄ are the third monochrome collimator C ₁ for removing scattering of X-rays that were not selectively reflected;
This is the fourth slit.

S ₂₅ is a fifth slit for detecting X-rays with a specific scattering angle εx ₀ among the X-rays scattered by the sample 23;
C ₂ is the X-ray source 2 selectively incident on the fifth slit S ₂₅
2 to the detector 24, this second monochrome collimator C ₂ is
It has the same configuration as the first monochrome collimator _C1 . In other words, this second monochrome collimator
C ₂ has a notched crystal part C 21 whose crystal surface is inclined at a predetermined angle θ B −θ ₀ with respect to the crystal lattice plane so that the reflection is asymmetrical, and a crystal part C ₂₁ where the crystal surface is tilted at a predetermined angle θ _B −θ 0 with respect to the crystal lattice plane so that the reflection is symmetrical. Crystal part with parallel notches on the crystal surface
C ₂₂ are cut out from a single single crystal so that they are substantially opposed to each other, and the crystal part of the former is
C ₂₁ is arranged and configured such that the incident angle θ ₀ of the X-ray 22 on the crystal surface is smaller than its reflection angle θh. Note that the first and second monochrome collimators C ₁ and C ₂ have the same single crystal lattice spacing d in order to monochromate X-rays;
Monochrome collimator C ₁ is mainly used to collimate X-rays, and also used as a second monochrome collimator
C ₂ is used to improve the angular resolution of scattered X-rays, and since their purposes are different, the crystal part of the first monochromatic collimator C ₁
The angle of incidence of the X-rays on C ₁₁ does not necessarily have to match the angle of incidence of the X-rays on the crystal part C ₂₁ of the second monochromatic collimator C ₂ . θ _B −
θ ₀ is set.

S ₂₆ and S ₂₇ are sixth and seventh slits for preventing air scattering, and S ₂₈ is a solar slit for limiting vertical divergence when a linear X-ray source extending perpendicular to the plane of the paper is used. And the above-mentioned 5th to 7th slits
S ₂₅ to _{S 27} , the solar slit S ₂₈ , the second monochrome collimator C ₂ , and the detector 24 are arranged on a single rotary table (not shown), and this rotary table is driven by, for example, a pulse motor. Accordingly, the detector 24 is configured to detect only X-rays scattered at a specific scattering angle εx ₀ .

Next, the operation of the apparatus having the above configuration will be explained.

X-rays 22 from the X-ray source 21 pass through the first and second slits S ₂₁ and S ₂₂ and enter the first monochrome collimator C ₁ . The crystal part C ₁₁ constituting the first monochromatic collimator is made of a single crystal whose crystal surface has been cut out with a predetermined angle θ _B −θ ₀ with respect to the crystal lattice plane, and On the other hand, since the X-rays are arranged so that the incident angle θ ₀ is smaller than the reflection angle θh (θ ₀ < θh), the incident X-rays are reflected asymmetrically, and at that time, they are monochromated and collimated. will be done. That is, among the X-rays incident on the crystal part _C11 , only the X-rays with a specific wavelength λ are selectively reflected according to Bragg's diffraction conditional expression. In addition, in asymmetric reflection, if the angular ranges of incidence and reflection are ω ₀ and ωh, respectively, ωh＝ω ₀・|b|=ωs・√||...(2) (However, b indicates the degree of asymmetry. , b=sinθ ₀ /
sinθh, and ωs indicates the angular range in the case of so-called symmetric reflection in which the crystal surface is cut parallel to the crystal lattice plane), so |b
_{| _}
θh), ωh in equation (2) becomes extremely small, and a collimated X-ray flux is obtained. The collimation in this case is the X-ray source 21
Since the distance between the sample 21 and the sample 23 is irrelevant, the distance between the two 21 and 23 can be significantly shortened, and the entire apparatus can be made smaller. In addition, by setting in advance the incident angle θ ₀ of the X-rays on the crystal surface to be sufficiently smaller than the reflection angle θh, it is possible to
Since the light-receiving area of C ₁₁ for incident X-rays increases, the total intensity of the X-rays reflected by the crystal portion C ₁₁ increases. Therefore, when a sample is irradiated with these X-rays, the total intensity of the scattered X-rays also increases. The X-rays that have been monochromatically collimated by the crystal part C ₁₁ are then reflected by the crystal part C ₁₂ . Since the X-rays are reflected symmetrically at this crystal part _C12 ,
The parallelism of the X-rays 22 remains unchanged. And the crystal part
The X-rays reflected by C ₁₂ pass through the third and fourth slits.
The light passes through S ₂₃ and S ₂₄ and is irradiated onto the sample 23.

The X-rays 22 incident on the sample 23 are scattered at various scattering angles εx as scattered X-rays with an intensity distribution corresponding to the state of the sample 23. Of the X-rays scattered at various scattering angles εx, the X-rays scattered at a specific scattering angle εx ₀ pass through the fifth slit S ₂₅ and enter the second monochrome collimator C ₂ .
The scattered X-rays are asymmetrically reflected by the crystal part _C21 of the second monochrome collimator _C2 , but in this case, the scattered X-rays are reflected by the first monochrome collimator _C1.
Like the crystal part C ₁₁ of , it reflects only the scattered X-rays included in the angular range ω ₀ , so the angular resolution of the scattered X-rays is substantially given by the above-mentioned angular range ω ₀ . Here, from the relationship in equation (2) above, ω ₀ is given by ω ₀ =ωs・√ ₀ ...(3), but in this equation, in a single crystal used for X-ray diffraction, usually Since ωs has a very small value, ω ₀ will be a small value regardless of the influence of the magnitudes of θh and θ ₀ . Therefore, the angular resolution required for practical use can be sufficiently ensured. Furthermore, since this angular resolution is achieved using the asymmetric reflection of the crystal part C ₂₁ , it is independent of the distance between the sample 23 and the detector 24, and therefore these distances can be significantly shortened. This allows the entire device to be miniaturized. In addition, since the incident angle θ ₀ of the X-ray is set in advance to be smaller than the reflection angle θh, the receiving area of the incident X-ray on the crystal part C ₁₁ becomes large, and therefore, the incident X-ray is reflected by the crystal part C ₂₁ . The total intensity of the X-rays emitted increases. Therefore, the total intensity of the X-rays detected by the detector 24 also increases.

In this way, among the scattered X-rays, only the scattered X-rays included in the predetermined angle range necessary for intensity measurement are detected at the crystal part.
It is selectively reflected at C ₂₁ and then reflected at crystal part C ₂₂ . Since this reflection from the crystal part C ₂₂ is a symmetrical reflection, the parallelism of the X-rays 22 does not change. The scattered X-rays selectively reflected by the second monochromatic collimator C ₂ pass through the sixth slit S ₂₆ , the solar slit S ₂₈ and the seventh slit S ₂₇ and are detected by the detector 24 .

By measuring the X-ray intensity for each scattering angle εx in this manner, an X-ray intensity distribution is obtained, and the structure of the sample can be analyzed thereby.

Next, a specific example will be shown.

An enclosed type X-ray tube (target: Cu, CuKα ₁ =1.54056 Å) is used as the X-ray source 21, and the first and second monochromatic collimators C ₁ and C ₂ are both made of (111) plane of Ge single crystal. Using the reflection of Also, if the incident angle θ ₀ of X-rays to the crystal surface is 2.51°, then θ _B = 11.31° + 2.51° =
It becomes 14.22°. At this time, the reflection angle θh of the X-ray with respect to the crystal surface is θh=14.22°+11.31°=25.53°. Therefore, the degree of asymmetry b in equation (2) is: b=sinθ ₀ /sinθh = sin (2.51°)/sin (25.53°)≒0.1.

The reflection intensity I of X-rays in the case of asymmetric reflection is
According to Darwin's formula, I=K・₀ =K・√1 (where K is a constant), so each diffraction X of the first and second monochromatic collimators C ₁ and C ₂
The intensity of the line is I ₁ and I ₂ is the intensity in the case of symmetrical reflection.
If expressed as a relative value, I ₁ = I ₂ =√1≒3.1. Therefore, the detection efficiency of scattered X-ray intensity is due to the synergistic effect of the first and second monochromatic collimators C ₁ and C ₂ √1×√1≒10 In other words, it is approximately 10 times as much as when using symmetric reflection. .

Furthermore, the resolution of the device for measuring the lattice spacing d of the sample is given by the relationship of equation (1): λ/ε ₀ = λ/(ωh + ω ₀ ) (where ωh is the reflection angle of the first monochromatic collimator C ₁ range, ω ₀ is the second monochrome collimator C ₂
incident angle range). here,
CuKα ₁ = 1.54056Å, ωh = 5.1″ (theoretical value), ω ₀ =
51.5" (theoretical value), so λ/Δ=1.54056/(5.1+51.5) = 5.6×10 ³ Å. On the other hand, the resolution when using symmetric reflection under the same conditions is 9.7 ×10 ³ Å, and compared to this case, the method of the present invention can obtain higher resolution.

In the above embodiment, the first and second monochromatic collimators C ₁ and C ₂ have crystal parts C ₁₁ C ₂₁ for asymmetric reflection.
A channel-cut type is used in which the crystal parts C ₁₂ and C ₂₂ for symmetrical reflection are cut out of a single single crystal, but the present invention is not limited to this. As shown in the figure, a single single crystal was cut out so that the crystal surface was inclined at a predetermined angle θ _B −θ ₀ with respect to the crystal lattice plane to produce crystal parts C ₁₁ and C ₂₁ so as to produce asymmetric reflection. , so-called single-cut monochrome collimators C ₃ and C ₄ may be used.

In addition, in FIGS. 1 and 3, the third to fifth slits S ₂₃ to S ₂₅ and the first and second monochrome collimators C ₁ (C ₃ ) and C ₂ (C ₄ ) are removed, and
The remaining slits S ₂₁ , S ₂₂ , S ₂₆ to _{S 28} and the detector 24 are positioned on the optical axis indicated by the broken line, and further,
If a solar slit is arranged between the slits S ₂₁ and S ₂₂ and configured to rotate the sample 23 and the detection system with a relationship of θ-2θ, it can function as a goniometer for a normal X-ray diffraction device. .

(Effects of the Invention) According to the present invention, X due to asymmetric reflection of a single crystal
Since the first and second monochromatic collimators are configured by utilizing the property of reducing the angular spread of the ray flux, the entire device can be downsized without impairing the scattered X-ray intensity and scattering angular resolution that can be used for practical purposes. Therefore, for example, excellent effects such as being able to be used for measuring small-angle X-ray scattering can be achieved without major changes to the goniometer included in an existing X-ray diffraction apparatus.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and Fig. 1 is a configuration diagram showing an outline of the small-angle X-ray scattering measuring device of the present invention, and Fig. 2 shows a cut-out channel constituting the first and second monochrome collimators. Diagram showing a single crystal,
FIG. 3 is a configuration diagram showing another modification. 21...X-ray source, 22...X-ray, 23...sample, 24...detector, _C1 - _C4 ...monochrome collimator, _S21 - _S27 ...slit, _S28 ...solar slit.

Claims (1)

[Claims] 1. Between the X-ray source and the sample, a first monochrome collimator that guides the X-rays from the X-ray source to the sample,
Further, second monochrome collimators are arranged between the sample and the detector to guide the X-rays scattered by the sample to the detector, and the first and second monochrome collimators are arranged so that the X-rays are reflected asymmetrically. Consisting of a single crystal whose crystal surface is notched at a predetermined angle with respect to a crystal lattice plane, and arranged so that the incident angle of X-rays on the crystal surface is smaller than the reflection angle. X
Small-angle line scattering measurement device.