JPH06317545A - Method and device for x-ray analysis - Google Patents

Abstract

PURPOSE:To simplify a drive mechanism attached to the second crystal monochromator, in An EXAFS(X-ray wide range absorption fine structure) measurement device that uses two crystal monochromators, by widening the interval between grid faces of the second crystal monochromator. CONSTITUTION:The X-ray from a focus F of an X-ray tube 68 is reflected by the first crystal monochromator 70 and the second crystal monochromator 74, and then after transmitting through a transmission X-ray detector 78, applied to a sample 80, and the fluorescence from it is detected by an X-ray detector 81. The first crystal monochromator 70 is Ge (440) and the second crystal monochromator 74 is PET (pentaerythritol)(002), with the interval between grid faces of the latter being larger than that of the former. At the first crystal monochromator 70, incident angle and distance are interlocked-driven for making the X-ray of mono color, and at the second crystal monochromator 74, using a small incident angle with distance fixed, low-order and high-order wavelengths are removed. With this, the drive mechanism related to the second crystal monochromator 74 is simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention separates continuous X-rays with two crystal monochromators to extract monochromatic X-rays of arbitrary wavelengths, and irradiates a sample by changing the wavelength of the monochromatic X-rays. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray analysis apparatus and method for analyzing a sample, and particularly to an EXA using two crystal monochromators.
The present invention relates to an FS measuring device and method.

[0002]

2. Description of the Related Art An EXAFS (X-ray wide area absorption fine structure) measuring apparatus is an apparatus for measuring a fine X-ray absorption spectrum near the absorption edge of a sample. In this device, continuous X-rays are spectrally separated by a crystal monochromator to extract monochromatic X-rays of an arbitrary wavelength, and this wavelength can be changed to measure the X-ray absorption coefficient of a sample. As a crystal monochromator for spectrally analyzing X-rays, a curved crystal monochromator is often used in order to gain strength.

In such an EXAFS measuring device,
To measure the high energy region above 15 keV,
The Bragg reflection angle of the crystal monochromator must be reduced, but simply reducing the Bragg reflection angle is not sufficient for monochromatization and is not practical. Therefore, in the measurement of such a relatively high energy region, high-order reflection such as second-order, third-order, and fourth-order Bragg reflection is used. In this case, unnecessary low-order and high-order reflections are present on the reflection side of the crystal monochromator in addition to the X-rays of the target energy. In the EXAFS measurement, the presence of such unnecessary X-rays significantly disturbs the measurement result and adversely affects the measurement result.

Since it is generally difficult to completely remove these unwanted interfering X-rays on the side of the X-ray detector, it has been proposed to add another crystal monochromator to remove the interfering X-rays. There is. That is, it is a method using two crystal monochromators (two-crystal method). In this case, by making the lattice spacing of the second crystal monochromator different from the lattice spacing of the first crystal monochromator, only the X-rays of the target energy can be extracted from the second crystal monochromator. That is, other low-order and high-order energy X-rays do not satisfy the black reflection condition in the second crystal monochromator, and the monochromaticity becomes complete.

FIG. 7 is a plan view showing a schematic basic structure of a conventional EXAFS measuring apparatus of the two-crystal method. The X-ray emitted from the X-ray focal point F passes through a divergence slit (not shown) and enters the first crystal monochromator 10 at an incident angle θ1, and of the X-rays reflected here, it corresponds to the incident angle θ1. Only X-rays having a wavelength satisfying the Bragg condition reach the first light receiving slit A. The X-rays that have passed through the first light receiving slit A are
It is incident on the second crystal monochromator 12 at an incident angle θ2,
Of the X-rays reflected here, only the X-rays having a wavelength satisfying the Bragg condition corresponding to the incident angle θ2 reach the second light receiving slit B. The X-rays that have passed through the second light receiving slit B are monochromaticized to a predetermined wavelength, pass through the transmission type proportional counter 14, pass through the sample 16, and reach the scintillation detector 18. The X-ray intensity before passing through the sample 16 is detected by the proportional counter 14, and the X-ray intensity after passing through the sample 16 is detected by the scintillation detector 18.
By comparing the X-ray intensities before and after transmission of sample 16,
The X-ray absorption coefficient of Sample 16 can be obtained.

When the lattice spacings of the first crystal monochromator 10 and the second crystal monochromator 12 are made different, the light is reflected by the first crystal monochromator 10 and passed through the first light receiving slit A. Of the X-rays, low-order and high-order X-rays other than the target energy are cut by the second crystal monochromator 12, and only the target energy X-ray is obtained at the second light receiving slit B. .

X-ray focus F and first crystal monochromator 1
0 and the first light-receiving slit A are on the first Rowland circle 20. The first light receiving slit A, the second crystal monochromator 12 and the second light receiving slit B are on the second Rowland circle 22. The surfaces of the first crystal monochromator 10 and the second crystal monochromator 12 are curved along the respective Rowland circles 20 and 22. In order to change the wavelength of the X-ray to be extracted, it is necessary to change the incident side and reflection side distances of each crystal monochromator and the incident angle. That is, the incident side and reflection side distance L1 of the first crystal monochromator 10 and the incident angle θ1 are changed, and the incident side and reflection side distance L2 and the incident angle θ2 of the second crystal monochromator 12 are also changed. At that time, the X-ray focus F, the first crystal monochromator 10 and the first light receiving slit A are always on the first Rowland circle 20, and the first light receiving slit A and the second crystal monochromator 12 are also provided. And the second light receiving slit B is always on the second Rowland circle 22.

[0008]

The above-mentioned conventional two-crystal method EXAFS measuring device is excellent in the performance of monochromatization in the high energy region, but has the following problems.

(1) A distance varying mechanism for varying the distances on the incident side and the reflecting side and a rotary drive mechanism for varying the incident angle are arranged around the crystal monochromator. When two crystal monochromators are used, the variable distance mechanism and the rotary drive mechanism may mechanically interfere with each other, and therefore, the angular range of the rotary drive mechanism is limited, and the scanning angle range of the crystal monochromator is limited. It may be done.

(2) Since the distance varying mechanism and the rotation driving mechanism are attached to each of the two crystal monochromators,
The entire device becomes large and expensive.

(3) A skill is required to optimally adjust the two crystal monochromators so that they always satisfy the concentration method.

Such a problem is not limited to the EXAFS measuring apparatus, and continuous X-rays are separated by two crystal monochromators to extract a monochromatic X-ray having an arbitrary wavelength, and the wavelength of the monochromatic X-ray is changed. This is a problem common to all X-ray analyzers that analyze a sample by irradiating the sample.

Therefore, an object of the present invention is to disperse continuous X-rays with two crystal monochromators to obtain a monochromatic X-ray having an arbitrary wavelength.
In connection with an X-ray analyzer that extracts a ray and irradiates the sample by changing the wavelength of this monochromatic X-ray, the mechanism attached to the second crystal monochromator is particularly small and simple. An object of the present invention is to provide an X-ray analysis apparatus and method that can be realized.

[0014]

[Means and Actions for Solving the Problems] The first invention is
In an X-ray analyzer for analyzing a sample by separating continuous X-rays with two crystal monochromators to extract monochromatic X-rays of an arbitrary wavelength, irradiating the sample by changing the wavelength of the monochromatic X-rays, The distance between the diffraction grating planes of the second crystal monochromator close to the sample is made larger than the distance between the diffraction grating planes of the first crystal monochromator close to the X-ray source, and the monochromatic X-rays extracted from the second crystal monochromator. The distance on the incident side and the distance on the reflecting side are fixed during the period of measurement while changing the wavelength of. Here, the incident side distance with respect to the second crystal monochromator refers to the distance from the first light receiving slit to the second crystal monochromator, and the reflection side distance is with respect to the second crystal monochromator. Indicates the distance to the light receiving slit.

In general, in order to change the X-ray wavelength extracted by using the crystal monochromator, it is necessary to change the incident angle to the crystal monochromator and change the incident side distance and the reflection side distance accordingly. . On the other hand, in the present invention, in the second crystal monochromator, the incident side distance and the reflection side distance are kept fixed even if the incident angle is changed. However, if this is simply done, the first light-receiving slit and the second light-receiving slit will deviate from the Rowland circle along the second crystal monochromator, and the X-ray intensity obtained from the second light-receiving slit will increase. It can be extremely small. Therefore, in the present invention, the distance between the diffraction grating planes of the second crystal monochromator is made larger than the distance between the diffraction grating planes of the first crystal monochromator to compensate for such a defect. That is, when the lattice spacing of the second crystal monochromator is increased, it is necessary to reduce the incident angle in order to extract the monochromatic X-ray having the target wavelength. Then, when the incident angle is changed and the X-ray wavelength to be extracted is changed, the required change amounts of the incident side distance and the reflection side distance are also relatively small. Therefore,
Even if the distance on the incident side and the distance on the reflecting side are fixed, the error from the proper proper distance becomes relatively small, and X is practically sufficient.
The line intensity can be obtained. In addition, the use of the present invention may cause a decrease in monochromaticity, but since the first crystal monochromator has already made monochromaticity, the second crystal monochromator basically has a low-order or high-order X-ray. It suffices to remove only the line, and the present invention does not pose any practical problem.

The crystal material which can be used as the second crystal monochromator having a large diffraction grating surface spacing d is shown in Table 1 below.
There is one shown in. The unit of 2d is Angstrom.

[0017]

Table 1 Crystal Material 2d PET (002) 8.76 EDDT (020) 8.803 Ge (111) 6.533 ADP (101) 10.648 TAP (001) 25.763 RAP (001) 26.121 Graphite (0002) 6.708 Various artificial lattice crystals 50-200 NaCl (200) 5.640 Mica 19.95 Quartz (101) 6.686

In a second aspect of the invention, the material of the second crystal monochromator in the first aspect is pentaerythritol (C
(CH ₂ OH) ₄ ). This pentaerythritol is generally abbreviated as PET. When the (002) plane of the PET crystal is used as the reflection surface, 2d = 8.76 angstroms when the lattice plane spacing is d. Ordinary crystal monochromator is 2d better than this PET
Is small, for example, on the (220) plane of Ge, 2d =
It is 4.001 angstrom. Such a normal crystal material is used as the first crystal monochromator.

In a third aspect of the present invention, continuous X-rays are separated by two crystal monochromators to extract monochromatic X-rays having an arbitrary wavelength, and the wavelength of the monochromatic X-rays is changed to irradiate the sample. In the X-ray analyzer for analysis, the crystal perfection of the second crystal monochromator close to the sample is measured by X-ray analysis.
The crystallinity of the first crystal monochromator close to the radiation source is set lower than that of the first crystal monochromator, and the second crystal monochromator is incident according to the wavelength during the measurement while changing the wavelength of the monochromatic X-ray to be extracted. The side distance and the reflection side distance are fixed.

In the third invention, instead of using a material having a large lattice spacing as the second crystal monochromator,
By using a material with low crystal perfection, the distance on the incident side and the distance on the reflecting side of the second crystal monochromator can be fixed. If the crystal integrity is low, the degree to which the reflected X-rays of the desired wavelength are concentrated on the Rowland circle is relatively low, so even if the distance on the incident side and the distance on the reflecting side deviate from the proper proper distance, From the light receiving slit of 2, a practically sufficient X-ray intensity can be obtained. As for the monochromaticity, as in the first invention, it has already been monochromaticized by the first crystal monochromator, and basically the second crystal monochromator has only to remove low-order or high-order X-rays. Well, there is no practical problem even if the present invention is adopted.

Examples of the material having low crystal perfection include graphite, mica, and artificial lattice. In order to evaluate the completeness of the crystal, the rocking curve of the crystal may be measured by X-ray diffraction measurement, and the full width at half maximum of the rocking curve may be compared. It can be said that the larger the half width, the lower the crystal perfection. For example, on the (0002) plane of graphite,
This half-value width is about 0.4 degree (1440 seconds), but the half-value width is 16 seconds for Ge (111) with high crystal perfection.

In a fourth aspect of the invention, the material of the second crystal monochromator in the third aspect is graphite. Graphite has a lower crystal perfection than Ge or Si,
It is suitable for use like the invention of.

A fifth invention is an application of the first to fourth inventions described above to an EXAFS measuring apparatus.

According to a sixth aspect of the present invention, continuous X-rays are separated by two crystal monochromators to extract a monochromatic X-ray having an arbitrary wavelength, and the wavelength of the monochromatic X-ray is changed to irradiate the sample. The X-ray analysis method for analysis has the following features. (A) Regarding the first crystal monochromator, both the incident side distance and the reflection side distance are changed and the incident angle is also changed during the period in which the wavelength of the monochromatic X-rays with which the sample is irradiated is changed. (B) Regarding the second crystal monochromator, both the incident side distance and the reflection side distance are fixed and only the incident angle is changed during the period in which the wavelength of the monochromatic X-rays with which the sample is irradiated is changed.
When the device of the first invention and the device of the third invention are used, a method as in the sixth invention is obtained.

In a seventh aspect of the invention, continuous X-rays are separated by two crystal monochromators to extract monochromatic X-rays of an arbitrary wavelength, and the wavelength of the monochromatic X-rays is changed to irradiate the sample. The X-ray analysis method for analysis has the following features. (A) Monochromatic X that irradiates the sample
During the period of changing the wavelength of the line, both the incident side distance and the reflecting side distance of the first crystal monochromator are changed, and the incident angle is also changed. (B) During the period in which the wavelength of the monochromatic X-ray irradiating the sample is changed, both the incident side distance and the reflection side distance of the second crystal monochromator are fixed and the incident angle is also fixed. In the seventh aspect of the invention, the incident angle and the distance on the incident side and the distance on the reflecting side are all fixed during the period in which the wavelength is changed in the second crystal monochromator, and the sixth aspect is further simplified. It is a thing. It is the same as the sixth invention that such a method becomes possible by increasing the lattice spacing of the second crystal monochromator or lowering the crystal perfection. Depending on the purpose of measurement, such a simplified method is also effective.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a sample horizontal type fluorescent EXA according to the present invention.
It is a front view of the example applied to the FS measuring device. The X-rays emitted from the focus F of the rotating anticathode X-ray tube 68 of the motor direct connection type are reflected by the first crystal monochromator 70 and collected in the first light receiving slit 72, and further by the second crystal monochromator 74. The light is reflected and collected at the second light receiving slit 76.
The X-rays that have passed through the second light receiving slit 76 are transmitted through the transmissive X-ray detector 78 and applied to the sample 80, and the fluorescence from the sample 80 is detected by the X-ray detector 81. This EXAFS measuring device uses a vertical pantograph link type concentration method for the first crystal monochromator 70. The first link 82 and the second link 84 are rotatably connected to the apparatus frame, and the third link 86 is connected to the tips of these two links. One end of the fourth link 88 has the first link 8
The other end of the fourth link 88 is connected to the horizontal slide base 90. The length of these four links are all equal to the radius of the Rowland circle. The focal point F of the X-ray tube 68 is on the rotation center of the first link 82, and the first crystal monochromator 70 has the second link 84 and the third link 8.
6 and the first light receiving slit 72.
Is on the connection point between the fourth link 88 and the horizontal slide base 90. With such a configuration, the X-ray focal point F, the first crystal monochromator 70, and the first crystal monochromator 70 are irrespective of the movement of the link.
The light receiving slit 72 of is always maintained on the Roland circle,
Satisfies the concentration condition. The X-ray focal point F and the first light receiving slit 72 are always on the horizontal straight line 73.

In order to perform the fluorescence EXAFS measurement of the sample 80, the X-ray incident angle with respect to the first crystal monochromator 70 is changed by using the above-mentioned pantograph link type monochromator, and thereby the sample is irradiated. The fluorescent X-ray spectrum of the sample is measured while changing the wavelength of the X-ray. The sample 80 is held on the sample table 92, and the sample table 92 is held.
Is always kept horizontal by the sample horizontal support mechanism 94. The X-ray detector 81 is fixed to the sample table 92 during the measurement.

FIG. 1 described above shows a state in which the spectral angle 2θ of the first crystal monochromator 70 is 34 degrees. On the other hand, FIG. 2 shows a state in which the spectral angle 2θ of the first crystal monochromator is 90 degrees. As can be seen from FIGS. 1 and 2, the X-ray tube 68 is designed to rotate about the focal point F in accordance with the movement of the pantograph link, and the X-ray beam is always directed toward the first crystal monochromator 70. It is designed to be taken out.

FIG. 3 shows an example of a transmission type EXAFS measuring apparatus. What is different from the apparatus shown in FIG. 1 is the configuration after the transmission type X-ray detector 78. The X-rays that have passed through the transmission type X-ray detector 78 pass through the sample in the sample box 30 and are detected by the scintillation detector 32.

Next, the structure in the vicinity of the second crystal monochromator 74 will be described. FIG. 4 is a front view showing the structure in the vicinity of the second crystal monochromator 74 of the EXAFS measurement device shown in FIG. The (002) plane of PET crystal is used as the second crystal monochromator 74. The second crystal monochromator 74 is mounted on the θ rotary table 34, and the θ rotary table 34 rotates around the center 35 by the action of the θ drive motor 36. The transmission type X-ray detector 78, the sample box 30, and the scintillation detector 32 are mounted on the 2θ rotary table 38 via a linear moving table, and the 2θ rotary table 38 is centered by the function of the 2θ drive motor on the back side in the drawing. Three
Rotate around 5. The distance between the first light receiving slit 72 and the center 35 of the second crystal monochromator 74, that is, the incident side distance can be adjusted by rotating the adjusting screw 40. The distance between the second light receiving slit 76 and the center 35 of the second crystal monochromator 74, that is, the reflection side distance can be adjusted by rotating the adjusting screw 42.

In this embodiment, since the (002) plane of PET is used as the second crystal monochromator, the lattice plane spacing is large and the incident angle θ can be made small. The distance on the incident side and the distance on the reflecting side are equal to each other, where L = 2R sin θ. Therefore, if the incident angle θ becomes small, the distance L becomes small, and the device size in the vicinity of the second crystal monochromator can be made small. Moreover, since the incident angle θ is small, the arrangement of the first light receiving slit, the second crystal monochromator, and the second light receiving slit is close to a linear arrangement. Therefore, the rotary drive mechanism around the second crystal monochromator does not interfere with the scan angle range around the first crystal monochromator.

Although the resolution of the second crystal monochromator is poor due to the low angle reflection, the resolution required for the EXAFS measurement is maintained by the first crystal monochromator. The second crystal monochromator is intended to remove interfering X-rays of low and high order wavelengths and has sufficient resolution for this purpose. On the contrary, the second crystal monochromator is easy to adjust because the resolution is insensitive.

Table 2 below shows the energies E of the K absorption edges of various elements, the angle of 2θ when using a crystal monochromator of the PET (002) plane, and the distances L on the incident side and the reflecting side. It is a thing. The radius of the Rowland circle in the second crystal monochromator is 320 mm. As can be seen from Table 1, it is possible to measure at an incident angle of about 2θ = 5 to 10 °, which is small for energy of 15 keV or more.

[0034]

Table 2 Element E (eV) 2θ (°) L (mm) Kr 14326 11.34 63.23 Rb 15200 10.69 59.59 Sr 16105 10.08 56.24 Y 17038 9.53 53.16 Mo -Ka 17480 9.29 51.82 Zr 17998 9.02 50.33 Nb 18986 8.55 47.71 Mo 20000 8.12 45.29 20330 7.98 44.55 Tc 21044 7.71 43.04 Ru 22117. 7.34 40.95 Rh 23220 6.99 39.01 Pd 24350 6.66 37.20 Ag 25514 6.36 35.50 Cd 26711 6.007 33.91 In 27940 5.81 32.42 Sn 29200 5. 56 31.02 Sb 30491 5.32 29 .71 Te 31814 5.10 28.47

In the EXAFS measurement, since the measurement energy varies depending on the measurement element, a crystal monochromator that scans a wide energy range of 5 to 30 keV is required, and the incident side distance and the reflection side distance also greatly change. . However, the measured energy width for one element is about 1 keV. As can be seen from Table 2, P
When using a crystal monochromator of ET (002), 1
Within the measurement range of the keV width, the change amount of 2θ Δ2θ = 1 °
It is the following. Further, the change amount ΔL of the distance L at this time is also relatively small, which is at most several mm or less. Therefore,
Even if the distance L is fixed during the period of measuring one element, sufficient reflection intensity can be obtained from the second light receiving slit. Moreover, since the resolution is lowered due to the low-angle incidence, even if the position of the second light receiving slit is slightly displaced, the X-ray intensity sufficient for the measurement can be obtained. The slit width of the second light receiving slit may be relatively large. The distance on the incident side and the distance on the reflecting side are actually fixed so as to satisfy the Bragg condition at the value of 2θ in the center of the measurement angle range. Therefore, this EXAFS device is not provided with an interlocking drive mechanism that changes the distance on the incident side and the distance on the reflecting side in association with the change in the incident angle. Only θ rotation and 2θ rotation are performed depending on the wavelength to be extracted.

FIG. 5A is a graph in which the X-ray intensity at the exit of the first crystal monochromator 70 is measured in the energy range of 17 to 18 keV. The operating condition of the X-ray source is X
The target of the wire tube is molybdenum, the tube voltage is 25 kV, and the tube current is 10 mA. The first crystal monochromator is Ge
(440). The two peaks in this graph are the two characteristic X-rays, namely MoKα1 and MoKα2.

FIG. 5B is a graph showing the X-ray intensity distribution of each pulse height in the wave height analyzer of the counting circuit under the condition of extracting the X-ray of 18 keV. In this graph, in addition to the pulse height count output corresponding to 18 keV, the pulse height count output corresponding to 9 keV of the low-order reflection is large. This low order reflection becomes an interference X-ray for the measurement at the target energy (18 eV).

FIG. 6A is a graph in which the X-ray intensity at the exit of the second crystal monochromator 74 is measured in the energy range of 17 to 18 keV. The operating condition of the X-ray source is X
The target of the wire tube is molybdenum, the tube voltage is 25 kV, and the tube current is 10 mA. The first crystal monochromator is Ge
(440) and the second crystal monochromator is PET
(002). The X-ray intensity in this graph is about 1/4 to 1/5 as compared with the X-ray intensity at the exit of the first crystal monochromator 70 in FIG. 5 (A). On the other hand, in the EXAFS measuring apparatus of the conventional two-crystal method, the X-ray intensity at the exit of the second crystal monochromator is the first
Since it is about 1/10 of the X-ray intensity at the exit of the crystal monochromator, it can be said that the EXAFS measuring apparatus of this embodiment can obtain a sufficient X-ray intensity as compared with the conventional example. Further, FIG. 6A shows a second crystal monochromator 74.
17 to 18 ke by fixing the distance on the incident side and the distance on the reflecting side of
Although measured in the range of V, the X-ray intensity is not significantly reduced near both ends of the energy range, although the distance is fixed.

FIG. 6 (B) is a graph showing the X-ray intensity distribution of each pulse height in the pulse height analyzer of the counting circuit under the condition of taking out 18 keV X-rays. Only a count output with a pulse height corresponding to 18 keV is obtained, and a count output with a pulse height corresponding to 9 keV of low-order reflection is hardly seen. This low-order reflection is cut by 90 to 95% or more by the second crystal monochromator.

After all, in the EXAFS measuring apparatus of this embodiment, in the first crystal monochromator having a normal lattice spacing, a relatively large incident angle is used to drive the incident angle and the distance in an interlocking manner to obtain good resolution. On the other hand, in the second crystal monochromator having a large lattice spacing, the X-rays are made monochromatic, while the low-order and high-order wavelengths are removed while the distance is fixed by using a small incident angle. This simplifies the structure around the second crystal monochromator, downsizes the entire apparatus, and reduces the possibility that the driving mechanisms around the two crystal monochromators interfere with each other.

In this embodiment, the scanning angle range of the incident angle in the first crystal monochromator 70 is 34 to 120 °, which is an angle in comparison with the scanning angle range 30 to 90 ° in the conventional two-crystal method. The range has become large. This is because the drive structure near the second crystal monochromator is the first.
This is because it is less likely to interfere with the driving structure near the crystal monochromator. The reason why the interference is less likely to occur is that the incident angle to the second crystal monochromator becomes smaller and the first
The device arrangement from the light receiving slit to the second light receiving slit is close to a straight line, and the driving structure in the vicinity of the second crystal monochromator is simplified. Further, since the incident side distance and the fixed side distance of the second crystal monochromator are fixed during the measurement, it is easy to adjust and operate the drive structure related to the second crystal monochromator.

The present invention is not limited to the above embodiment, but the following modifications are possible. (1) Graphite can be used instead of PET as the material of the second crystal monochromator. The crystallinity of graphite is considerably lower than that of ordinary monochromator materials, and the degree of concentration on the Rowland circle is low. Therefore,
When the distance on the incident side and the distance on the reflecting side are fixed with respect to the second crystal monochromator, it is advantageous in the sense of increasing the X-ray intensity.

(2) In the above-mentioned embodiment, with respect to the second crystal monochromator, the distance on the incident side and the distance on the reflecting side are fixed, but the incident angle is changed, during the measurement period while changing the wavelength. ing. On the other hand, it is possible to measure by fixing the incident side distance and the reflecting side distance and fixing the incident angle. In this case, the X-ray intensity is further reduced as compared with the case where the incident angle is changed, but this may be sufficient depending on the measurement purpose.

(3) The above-mentioned embodiment relates to a vertical type EXAFS measuring device (the Roland circle is in the vertical plane), but the present invention is a horizontal type (the Roland circle is in the horizontal plane). The same can be applied to the EXAFS measuring device of.

(4) In the present invention, in addition to the EXAFS measuring device, continuous X-rays are separated by two crystal monochromators to extract monochromatic X-rays of an arbitrary wavelength, and the wavelength of the monochromatic X-rays is changed. Any type of X-ray analyzer can be applied as long as it is an X-ray analyzer that analyzes the sample by irradiating the sample.

[0046]

According to the present invention, the second crystal monochromator having a large lattice spacing or a low crystal perfection is used, and the measurement is performed while changing the wavelength. Since the incident side distance and the reflection side distance of the second crystal monochromator are fixed, the driving mechanism related to the second crystal monochromator can be downsized and simplified. Further, this reduces the risk of interference between the drive mechanism associated with the first crystal monochromator and the drive mechanism associated with the second crystal monochromator, and expands the scanning angle range of the first crystal monochromator. it can.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention.

FIG. 2 is a front view showing another state of the device of FIG.

FIG. 3 is a front view of another embodiment of the present invention.

FIG. 4 is an enlarged front view of the vicinity of a second crystal monochromator.

FIG. 5 is a graph of the X-ray intensity distribution at the exit of the first crystal monochromator and the output data of the wave height analyzer.

FIG. 6 is a graph of the X-ray intensity distribution at the exit of the second crystal monochromator and the output data of the wave height analyzer.

FIG. 7 is a schematic plan view of a conventional EXAFS measurement apparatus using a two-crystal method.

[Explanation of symbols]

 68 ... X-ray tube 70 ... 1st crystal monochromator 72 ... 1st light receiving slit 74 ... 2nd crystal monochromator 76 ... 2nd light receiving slit 78 ... Transmission type X-ray detector 80 ... Sample 81 ... X-ray Detector

Claims (7)

[Claims] 1. A monochromatic X-ray having an arbitrary wavelength is extracted by separating continuous X-rays with two crystal monochromators.
In an X-ray analyzer for analyzing a sample by changing the wavelength of the rays and irradiating the sample, the diffraction grating plane spacing of the second crystal monochromator close to the sample is set to the first crystal monochromator close to the X-ray source. The distance between the diffraction grating planes of the meter is made larger, and the second crystal monochromator is characterized in that the incident side distance and the reflection side distance are fixed during the measurement period while changing the wavelength of the monochromatic X-ray to be extracted. X-ray analyzer. 2. The X-ray analysis apparatus according to claim 1, wherein the material of the second crystal monochromator is pentaerythritol. 3. A monochromatic X-ray having an arbitrary wavelength is extracted by separating continuous X-rays with two crystal monochromators.
In an X-ray analyzer that analyzes a sample by irradiating the sample by changing the wavelength of the X-ray, the crystal perfection of the second crystal monochromator close to the sample is compared to the first crystal monochromator close to the X-ray source. The second crystal monochromator is characterized in that the incident side distance and the reflection side distance are fixed during the period of measurement while changing the wavelength of the monochromatic X-ray to be extracted, in addition to the crystal perfection of the meter. X-ray analyzer. 4. The X-ray analysis apparatus according to claim 3, wherein the material of the second crystal monochromator is graphite. 5. The X-ray analysis apparatus according to claim 1, wherein the X-ray analysis apparatus is an EXAFS measurement apparatus. 6. A monochromatic X-ray having an arbitrary wavelength is extracted by separating continuous X-rays with two crystal monochromators.
An X-ray analysis method for analyzing a sample by irradiating the sample by changing the wavelength of the X-ray, the X having the following characteristics:
Line analysis method. (A) Regarding the first crystal monochromator, both the incident side distance and the reflection side distance are changed and the incident angle is also changed during the period in which the wavelength of the monochromatic X-rays with which the sample is irradiated is changed. (B) Regarding the second crystal monochromator, both the incident side distance and the reflection side distance are fixed and only the incident angle is changed during the period in which the wavelength of the monochromatic X-rays with which the sample is irradiated is changed. 7. A monochromatic X-ray having an arbitrary wavelength is extracted by separating continuous X-rays with two crystal monochromators.
An X-ray analysis method for analyzing a sample by irradiating the sample by changing the wavelength of the X-ray, the X having the following characteristics:
Line analysis method. (A) During the period in which the wavelength of the monochromatic X-rays irradiated to the sample is changed, both the incident side distance and the reflection side distance of the first crystal monochromator are changed and the incident angle is also changed. (B) During the period in which the wavelength of the monochromatic X-ray irradiating the sample is changed, both the incident side distance and the reflection side distance of the second crystal monochromator are fixed and the incident angle is also fixed.