JPH0666736A - X-ray spectroscope and exafs measuring instrument - Google Patents

Abstract

PURPOSE:To improve the angular accuracy of each X-ray optical element, such as a crystal monochromator, etc., of an X-ray spectroscope and, at the same time, to prevent the occurrence of the tilting of each optical element. CONSTITUTION:An X-ray source F, crystal monochromator 2, and light receiving slit 2 are always positioned on a Rowland circle L by means of a first rotary link 4, second rotary link 5, parallel-displacement link 8, and auxiliary link 21. At the time of moving the monochromator 1 in the vertical and lateral directions by means of a pulse motor 10, the X-ray optical axes of the source F, monochromator 1 and slit 2 are always aligned with each other by rotating the source F around a first rotation axis X1 by means of a pulse motor 19 and the slit 2 around a fifth rotation axis X5 by means of a pulse motor 25. Therefore, no deflection occurs in the links 4, 5, 8, and 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray spectroscope for diffracting X-rays emitted from an X-ray source by a crystal monochromator and condensing it on a light-receiving slit, and an EXA equipped with the spectroscope.
The present invention relates to an FS measuring device.

[0002]

2. Description of the Related Art EXAFS is an extended X-ray absorption fine structure (extended X-ray absorption fine structure).
Fine Structure), which is an absorption fine structure seen over a range of about 1 KeV from the X-ray absorption edge of a composition atom of a crystal sample or an amorphous sample toward the higher energy side. By observing the graphic pattern of this EXAFS, information on the atoms constituting the sample can be obtained. To measure this EXAFS, the energy of X-rays transmitted through the sample, that is, the ratio of the X-ray intensity before passing through the sample and the X-ray intensity after passing through the sample is changed while changing the wavelength. Will be asked about.

As this type of EXAFS measuring device, there is known one in which a crystal monochromator is moved by an X-ray spectroscopic device as shown in FIG. This spectroscope changes the wavelength of the X-ray reaching the light-receiving slit 52 while always positioning the X-ray source F, the crystal monochromator 51, and the light-receiving slit 52 on the Rowland circle L having a constant radius.

In this spectroscopic device, sliders 55 and 56 are slidably attached to two orthogonal guide rods 53 and 54, respectively. Two sliders 55,
Both ends of a first link 57 having a length of 2R are rotatably connected to 56. An arm 58 is rotatably connected to the slider 56, and the rotation center of the arm 58 is
It coincides with the center of rotation of the link 57. A slider 60 is slidably provided on a guide rod 59 fixed to the arm 58. One end of a second link 61 having a length R is rotatably connected to the midpoint O of the first link 57, and a slider 60 is rotatably connected to the other end of the second link 61. Monochromator slider 56
Is engaged with a feed screw 63 which is rotationally driven by a pulse motor 62, and the slider 60 on the slit side is engaged with a feed screw 65 which is rotationally driven by a pulse motor 64.

The X-ray source F is arranged at a position where the two guide rods 53 and 54 intersect. Guide rod 5
3, 54 and the X-ray source F are in a spatially stationary state. The crystal monochromator 51 is arranged so that its center coincides with the connection point P between the first link 57 and the slider 56, and is fixed to the first link 57. The middle point O of the first link 57 is the center of the Roland circle L. The X-ray reflecting surface of the crystal monochromator 51 is arranged along the Rowland circle L. The light receiving slit 52 is arranged so that its center coincides with the connection point Q between the second link 61 and the slider 60, and is fixed to the slider 60. On the right side of the light receiving slit 52, a sample 66 to be measured and an X-ray detector 67 are provided. All of these are fixed to the slider 60.

From the X-ray source F to the center P of the monochromator 51
To the center P of the monochromator 51.
To the center Q of the light receiving slit 52 is R2. This spectroscopic device interlocks and controls the pulse motors 62 and 64 so that R1 and R2 are always equal. Then, by changing the values of R1 and R2, the incident angle of the X-rays that enter the crystal monochromator 51 changes, and thus the wavelength of the X-rays that reach the light receiving slit 52 changes. When R1 and R2 are changed, the center O of the Roland circle L moves in space, but the radius R of the Roland circle L
Is constant.

[0007]

In the conventional X-ray spectroscopic apparatus described above, since relatively large force is applied to the first link 57 and the second link 61, the links are likely to be bent. The occurrence of such bending causes at least the following two problems. One is an X such as a monochromator mounted on each link, a light receiving slit, etc.
This means that the angle of the linear optical element cannot be accurately adjusted to the desired angle. The other is that each X-ray optical element is tilted in accordance with the bending of the link, causing a so-called tilt.

The present invention has been made to solve the above problems, and an object of the present invention is to improve the angular accuracy of each X-ray optical element and prevent the occurrence of tilting of each X-ray optical element. And

[0009]

An X-ray spectroscopic apparatus according to the present invention is located at a position away from a first rotary link that rotates around a first rotational axis that is positionally stationary and a first rotational axis. A second rotary link that rotates about a stationary second rotary axis; a parallel link that connects the two rotary links to each other; and a parallel link drive unit that drives the parallel link to translate the parallel link. An X-ray source provided on the first rotation axis and rotatable independently of the first rotation link, an X-ray source driving unit that rotationally drives the X-ray source, a second rotation link, and a parallel movement link. Between the first rotation link and the translation link, and the crystal monochromator fixed to the translation link and rotatably mounted on the third rotation axis between the first rotation link and the translation link. 4th axis of rotation Between the slider and the auxiliary link, a slider rotatably mounted on the auxiliary link, a slider rotatably provided on the auxiliary link, a slider guide means for guiding the slider in a direction perpendicular to the direction in which the translation link extends, A ω table rotatably provided on the fifth rotation axis, a light-receiving slit mounted on the ω table on the fifth rotation axis, and a ω table drive which is fixed on the slider and rotationally drives the ω table. Means for controlling the operations of the parallel link drive means, the X-ray source drive means and the ω table drive means so that the optical axis of the X-ray source, the optical axis of the crystal monochromator and the optical axis of the light-receiving slit always coincide with each other. It is characterized by having and.

[0010]

The angular positions of the X-ray source and the light-receiving slit are individually controlled by the X-ray source driving means and the ω table driving means. Also, the angular position of the crystal monochromator is maintained at a constant angle by a translation link that always translates. Each of the first rotary link, the second rotary link, the translation link and the auxiliary link is used only for positioning the X-ray optical elements such as the X-ray source, the crystal monochromator and the light receiving slit on the Rowland circle, It is not used as a rotational force transmission means for rotationally driving those optical elements. Therefore, bending does not occur in each link, and as a result, the angular accuracy of each X-ray optical element is improved, and the occurrence of tilting of each X-ray optical element is prevented.

[0011]

1 shows an embodiment of an X-ray spectroscopic apparatus according to the present invention and an EXAFS measuring apparatus according to the present invention using the same. This EXAFS measurement device is fixed to the frame 3 and is rotatable about a first rotation axis X1 which is positionally immovable, and a first rotation link 4 which is separated from the first rotation link 4 by an upper position. A second rotary link 5 that is fixed to the frame 3 and is rotatable around a second rotary axis X2 that is immovable, a translation link 8 that connects these two links 4 and 5, and a translation link. Parallel link drive 9 for driving 8
And have. First rotation axis X1 and second rotation axis X
Both 2 extend in the direction perpendicular to the paper surface.

The parallel link driving device 9 is a pulse motor 1
0, a rod-shaped feed screw 11 that is rotationally driven by the pulse motor 10, a traveling body 12 that is screwed to the feeding screw 11, and the traveling body 12 smoothly moves in the vertical direction in the figure without rattling. Guide you to do 2
The guide rods 13 and 13 of the book and the traveling body 12 are placed on the traveling body 12 in the left-right direction (Y
Direction) and a support piece 14 which can move freely. The parallel movement link 8 is fixed to the right end of the support piece 14. The pulse motor 10 is the spectroscopic control device 1
Operates while being controlled by 8.

An approximately disk-shaped worm wheel 15 is provided at the left end of the first rotary link 4, and an X-ray tube 16 provided with the X-ray source F integrally with the worm wheel 15.
Is provided. The worm wheel 15 is rotatable independently of the first rotation link 4 about the first rotation axis X1. Further, the X-ray tube 16 has the holder 1 so that the X-ray source F stored therein may be placed on the first rotation axis X1.
It is fixed on top of 6. On the left side of the X-ray tube 16, the X
An X-ray source drive device 17 for rotating and driving the X-ray tube 16 and the X-ray source F is provided.

The X-ray source driving device 17 includes a pulse motor 19
And a worm 20 rotatably driven by the pulse motor 19. The worm 20 meshes with the worm wheel 15.

The crystal monochromator 1 is fixedly attached to the upper end of the parallel movement link 8. The X-ray diffraction surface of the monochromator 1 is positioned so as to include a third rotation axis X3 which is an axis through which the second rotation link 5 and the parallel movement link 8 are rotatably connected to each other.
The monochromator 1 can freely rotate with respect to the second rotation link 5.

On the rotation axis between the first rotation link 4 and the parallel movement link 8, that is, on the fourth rotation axis X4, an auxiliary link 21 extending rightward in the drawing is provided rotatably about the rotation axis X4. Has been. A rectangular slider 22 is attached to the right end of the auxiliary link 21. The slider 22 can freely rotate about the fifth rotation axis X5 with respect to the auxiliary link 21. Further, the slider 22 includes two guide rods 23, 2
By being guided by 3, it is possible to move smoothly in a straight line in the left-right direction of the drawing without rattling.

A disk-shaped ω table 24 is mounted on the slider 22. This ω table 24 is
The slider 22 can freely rotate about a fifth rotation axis X5 extending in the direction perpendicular to the plane of the drawing. A ω table drive device 26 having a pulse motor 25 is fixedly arranged on the upper end of the slider 22, and the ω table 24 is moved by the drive device 26 to the fifth rotation axis X5.
It is driven to rotate around. The pulse motor 25 operates while being controlled by the spectroscopic control device 18.

On the ω table 24, the light receiving slit 2,
The ion chamber 27 and the sample 6 are arranged.
An X-ray detector 29 is fixedly arranged on a detector arm 28 extending from the ω table 24. The slit portion of the light receiving slit 2 is located on the axis of the fifth rotation axis X5. Further, the ion chamber 27 measures the intensity of the X-ray passing therethrough and outputs it as an electric signal. The output signal is sent to the arithmetic unit 30. The X-ray detector 29 measures the intensity of the X-ray captured therein and outputs it as an electric signal. The output signal is also sent to the arithmetic unit 30. A display device 31 such as a CRT monitor or a printer is electrically connected to the subsequent stage of the arithmetic device 30.

The operation of the EXAFS measuring device having the above structure will be described below.

The X-ray R1 emitted from the X-ray source F enters the crystal monochromator 1, and the X-ray having a wavelength corresponding to the incident angle θ at that time is diffracted by the monochromator 1. This diffracted X-ray R2
Are focused on the light-receiving slit 2, and the ion chamber 27
Then, after passing through the sample 6, it is taken into the X-ray detector 29. The ion chamber 27 measures the intensity I ₀ of the X-ray before passing through the sample 6, and the intensity I ₀ is sent to the arithmetic unit 30. The X-ray detector 29 measures the intensity I of the X-ray transmitted through the sample 6, and the intensity I is also sent to the arithmetic unit 30. The arithmetic unit 30 calculates a ratio I ₀ / I of both X-ray intensities and stores the result in a built-in memory.

When the above-mentioned one measurement is completed, the pulse motor 10 in the parallel link driving device 9 is operated to move the traveling body 12 in the vertical direction, for example, in the downward direction by a predetermined short distance,
Along with that, the parallel movement link 8 also moves in the vertical direction. At this time, the parallel movement link 8 is translated by the action of the first rotary link 4 and the second rotary link 5 while being oriented in the vertical direction, and further by the action of the support piece 14 sliding on the traveling body 12. It also moves in the left-right direction (Y direction).

When the crystal monochromator 1 is translated in the vertical and horizontal directions as described above, the slider 22 connected to the translation link 8 via the auxiliary link 21 is guided by the guide rods 23, 23. Translate in the horizontal direction. In this way, the monochromator 1 and the slider 22 move while being constrained by the first rotary link 4, the second rotary link 5, the parallel movement link 8, and the auxiliary link 21, so that the X-ray source F, the monochromator 1, and the light reception. Each optical element of the slit 2 always maintains the positional relationship of riding on the Roland circle L.

When the monochromator 1 and the light-receiving slit 2 move in the above-mentioned positional relationship, the worm wheel 15 is driven by the pulse motor 19 in the X-ray source driving device 17 to rotate an appropriate angle, and at the same time. The ω table 24 is driven by the pulse motor 25 in the ω table drive device 26 and rotated by an appropriate angle. The rotation of the worm wheel 15 changes the angle of the X-ray source F with respect to the crystal monochromator 1, while the rotation of the ω table 24 changes the angle of the light-receiving slit 2 with respect to the crystal monochromator 1. When the monochromator 1 and the light-receiving slit 2 move while maintaining the Rowland circle L due to the changes in the angles of the X-ray source F and the light-receiving slit 2, the optical axes of the X-ray source F, the monochromator 1 and the light-receiving slit 2 respectively. Are controlled so that they always match.

As described above, when the crystal monochromator 1 is moved in parallel in the vertical and horizontal directions by an appropriate distance, the incident angle θ of the X-rays on the monochromator 1 changes, and X diffracted by the monochromator 1 accordingly. The wavelength of the rays, or the X-ray energy, changes. This energy changed diffracted X-ray R
For 2, the X-ray intensity I ₀ before the sample is transmitted and the X-ray intensity I after the sample is transmitted are measured, and the intensity ratio I ₀ / I is calculated and further stored. After that, the crystal monochromator 1 is sequentially moved by an appropriate distance, and the X-ray intensity ratio I ₀ / I is obtained for various different X-ray incident angles θ.
The known EXAF is obtained by plotting the X-ray intensity ratio I ₀ / I thus obtained on a graph for each X-ray energy.
An S pattern is obtained, and the atomic structure of the sample can be estimated by observing the pattern of this EXAFS pattern.

In the EXAFS measuring apparatus described above, the ion chamber 27, the sample 6, the X-ray detector 29, the arithmetic unit 3
0, and the rest of the structure except the display device 31 is an X-ray spectroscopic device.

X-ray spectrometer and EXAF according to the present embodiment
Although the S measuring device uses four links 4, 5, 8 and 21, the optical elements of the X-ray source F, the crystal monochromator 1 and the light receiving slit 2 are always located on the Rowland circle L in these links. It only acts to constrain those positions. Then, the operation of rotationally driving each optical element in order to match the optical axes of the respective optical elements is performed by the parallel link driving device 9, the X-ray source driving device 17, and the ω table driving which are independently arranged. Performed by the device 26. As a result, each link 4, 5,
A large force is not applied to 8, 21 and they do not bend. Therefore, the angular accuracy of the X-ray optical element such as the crystal monochromator 1 mounted on each link can be accurately maintained,
Further, it is possible to prevent each X-ray optical element from tilting.

FIG. 2 shows another embodiment of the X-ray spectroscopic apparatus and the EXAFS measuring apparatus using the same according to the present invention. This embodiment is different from the previous embodiment shown in FIG. 1 in that the auxiliary link 21 is removed and a slider driving device 32 is provided instead. The slider driving device 32 extends in a direction perpendicular to the translation link 8 and is a rod-shaped feed screw 33 that is screwed to the slider 22.
And a pulse motor 34 that rotationally drives the feed screw 33.
It is composed of and. The pulse motor 34 operates while being controlled by the spectroscopic control device 18.

The crystal monochromator 1 is a pulse motor 10
When the light receiving slit 2 is driven by the pulse motor 34 to move in the vertical direction and the horizontal direction in parallel, the light receiving slit 2 is moved in the horizontal direction and is controlled so as to be always positioned on the Rowland circle L.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to these embodiments. For example, the X-ray spectroscopic device for controlling the position and angle of each optical element of the X-ray source F, the crystal monochromator 1, and the light-receiving slit 2 can be used in any X-ray utilizing device other than the EXAFS measuring device. it can.

[0030]

According to the present invention, it is possible to prevent the link mechanism having the X-ray optical element such as a crystal monochromator from bending. As a result, the positional accuracy and the angular accuracy of the X-ray optical element can be improved, and further, the fall of each X-ray optical element can be prevented.

[0031]

[Brief description of drawings]

FIG. 1 is an X-ray spectrometer according to the present invention and E using the same.
It is a front view showing an example of an XAFS measuring device.

FIG. 2 is an X-ray spectroscopic device according to the present invention and E using the same.
It is a front view showing other examples of an XAFS measuring device.

FIG. 3 is a plan view showing an example of a conventional X-ray spectroscopic device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crystal monochromator 2 Light receiving slit 4 1st rotation link 5 2nd rotation link 8 Parallel movement link 9 Parallel link drive device 17 X-ray source drive device 18 Spectroscopic control device 21 Auxiliary link 22 Slider 23 Guide rod 24 ω table 26 ω table Drive device 32 Slider drive device F X-ray source X1 First rotation axis line X2 Second rotation axis line X3 Third rotation axis line X4 Fourth rotation axis line X5 Fifth rotation axis line

Claims (3)

[Claims] 1. An X-ray spectroscopic apparatus that diffracts X-rays emitted from an X-ray source with a crystal monochromator and focuses them on a light-receiving slit.
A rotary link; a second rotary link that rotates around a second rotary axis that is distant from the first rotary axis and is stationary; a translation link that connects the two rotary links to each other; Parallel link driving means for driving the link to move it in parallel, X-ray source provided on the first rotation axis and rotatable independently of the first rotation link, and rotationally driving the X-ray source. A crystal that is provided on the third rotation axis between the X-ray source driving means and the second rotation link and the parallel movement link, is rotatable with respect to the second rotation link, and is fixed to the parallel movement link. The monochromator, the auxiliary link that rotates around the fourth rotation axis between the first rotation link and the parallel movement link, the slider that is rotatably provided on the auxiliary link, and the direction in which the parallel movement link extends. A slider guide means for guiding the slider in a direction perpendicular to the axis, an ω table rotatably provided on the fifth rotation axis between the slider and the auxiliary link, and an ω table on the fifth rotation axis. The mounted light-receiving slit, the ω-table driving means which is fixed on the slider and rotationally drives the ω-table, and the optical axis of the X-ray source, the optical axis of the crystal monochromator and the optical axis of the light-receiving slit always coincide with each other. Parallel link drive means,
An X-ray spectroscopic apparatus comprising: a control device that controls the operations of the X-ray source driving means and the ω table driving means. 2. A slider driving means for linearly driving the slider is provided in place of the auxiliary link, and further, an X-ray source,
2. The X-ray spectroscopic apparatus according to claim 1, wherein operations of the parallel link driving means and the slider driving means are controlled by the control device so that the crystal monochromator and the light receiving slit are always located on the Rowland circle. 3. The X-ray intensity before and after the sample is transmitted after diffracting the X-ray radiated from the X-ray source with a crystal monochromator and condensing it on a light-receiving slit. An EXAFS measuring device for measuring a ratio with the EX, comprising the X-ray spectroscopic device according to claim 1 or 2.
AFS measuring device.