JP2899056B2 - Optical axis adjustment method and apparatus for sample fixed X-ray diffractometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention measures the intensity of X-ray diffracted on a sample surface while rotating an X-ray generation unit and an X-ray detection unit around a fixed sample. To a so-called sample fixed X-ray diffractometer. In particular, it relates to a method and an apparatus for adjusting the optical axis of X-rays in the X-ray diffraction apparatus.

[Prior Art] It is already known that there are two types of X-ray diffractometers, a sample rotating X-ray diffractometer and a sample fixed X-ray diffractometer.

The sample rotation type X-ray diffractometer is such that the X-ray source is fixed, the sample is rotated by θ around the sample axis, and the X-ray detector is rotated by 2θ (twice θ) in accordance with the θ rotation. While measuring the diffraction X-ray intensity. On the other hand, a fixed sample X-ray diffractometer measures a diffracted X-ray intensity while fixing a sample and rotating an X-ray source and an X-ray detector around the fixed sample by θ around the sample.

By the way, in any of the above X-ray diffractometers, it is necessary to adjust the X-ray optical axis of the X-ray diffractometer to an appropriate state prior to the measurement. In the case of a fixed sample X-ray diffractometer, this optical axis adjustment usually comprises the following three steps.

(1) X-ray Focus Adjustment Step Generally, X-rays emitted from an X-ray source enter a sample through a divergence slit, diffract on the surface of the sample (that is, the sample surface), and then pass through a light-receiving slit. Received by an X-ray detector and its intensity is measured. X-ray source and X
When the line detectors are both located at the position of θ = 0 (horizontal position), that is, when both are located symmetrically with respect to the sample, the divergence slit, the sample surface, and the light receiving slit are straightforward. It is located on the line. This has been adjusted in advance in the manufacturing stage of the X-ray diffraction apparatus.

In order to perform an accurate measurement, it is required that the focal point of the X-ray source be accurately arranged on the straight line. The X-ray focus adjustment step is a step for adjusting the position of the X-ray source so that the focal point of the X-ray source is accurately located on the straight line.

(2) Sample reference plane adjustment step In order to accurately obtain the incident angle θ of the X-ray with respect to the sample, when the X-ray source and the X-ray detector are both at the position of θ = 0 (horizontal position), the X-ray source It is required that the traveling path of the X-rays exiting from the detector and received by the X-ray detector be exactly parallel to the sample surface. That is, when the X-ray source is at the position of θ = 0, the X-ray incident angle on the sample must be exactly θ = 0.

The sample reference plane adjustment step is a step for adjusting the sample plane and the X-ray traveling path so as to be parallel to each other, and setting a reference position where the X-ray incidence angle θ is zero.

(3) Adjustment Confirmation Step When each of the above steps is completed, it is necessary to confirm whether or not the optical axis adjustment has been accurately performed within the target accuracy range. The adjustment confirmation step is a step for confirming the adjustment.

In the X-ray diffractometer, the above-mentioned work for adjusting the optical axis is required.
In the X-ray diffraction apparatus, in the sample reference plane adjustment step among the above steps, the X-ray source and the X-ray detector are fixed at the position of θ = 0 (horizontal position), and the sample is centered on the sample axis. Then, the sample surface was adjusted to be parallel to the X-ray traveling path.

[Problems to be Solved by the Invention] In the conventional sample fixed X-ray diffractometer, as described above, the sample reference plane is adjusted by finely rotating the sample. A fine rotation mechanism was required. This fine rotation mechanism has a problem that the structure is complicated and the components constituting the mechanism must be finished with high precision, and therefore the cost is extremely high.

Usually, this fine rotation mechanism is disposed on the back side of the X-ray diffraction apparatus. Therefore, in order to finely adjust the rotation of the sample, the operator must turn to the back side of the X-ray diffraction apparatus each time. Was troublesome.

Furthermore, when performing X-ray diffraction measurement, since the sample must not be displaced, after the optical axis adjustment is completed, a clamp means for firmly fixing the sample is required. Therefore, there was a problem that the cost was high.

The present invention has been made in view of the above-mentioned problems in the conventional apparatus, and an optical axis adjustment method and apparatus which can perform X-ray optical axis adjustment easily and surely and can simplify the structure. The purpose is to provide.

[Means for Solving the Problems] In order to achieve the above object, an optical axis adjusting method according to the present invention provides a method of rotating an X-ray traveling path itself around a sample, thereby obtaining a sample surface and its X-rays. It is characterized in that the traveling paths are adjusted in parallel with each other.

Further, in the optical axis adjusting apparatus according to the present invention, the X-ray generating means (X-ray tube 12, X-ray focal point B) is set at the sample arrangement position (sample stage 4).
Source driving means (e.g., pulse motor 19 on the source side) for driving the rotation around the center, and detection driving means for rotating the X-ray detection means (X-ray detector 10) about the sample arrangement position (4) (Such as the detection side pulse motor 23) and control means (2) for controlling the operation of the source side drive means and the detection side drive means.
5) and has. The X-ray generation means and the X-ray detection means can be arranged at positions symmetrical with respect to the sample arrangement position (4), and the control device (25) The operation of the source-side drive unit and the detection-side drive unit is controlled such that the X-ray generation unit and the X-ray detection unit arranged at symmetrical positions rotate synchronously in the same direction and at the same angle by the same angle. It has become.

[Operation] In the optical axis adjusting method of the first aspect, the X-ray incident angle θ
In performing the step for setting the zero reference position (the sample reference plane adjustment step), instead of performing the fine rotation of the sample table as in the related art and performing the adjustment, the X-ray generation means is used. The X-ray traveling path is rotated to adjust the position. In that case, the X-ray traveling path is adjusted so as to be parallel to the sample surface, and thus to the reference surface (C) of the optical axis adjusting jig (27).

In the optical axis adjusting device according to the second aspect, the X-ray generating means (X-ray tube 12) is formed by the source driving means (the source pulse motor 19 and the like) and the detection driving means (the detection pulse motor 23 and the like). And the X-ray detection means (X-ray detector 10) are rotationally driven in the same direction by the same angle in synchronization with each other, whereby the X-ray traveling path from the X-ray generation means to the X-ray detection means is moved along the sample arrangement position. It is made to rotate around the center.

Embodiment FIG. 1 shows an embodiment of a sample fixed X-ray diffractometer to which an optical axis adjusting device according to the present invention is applied. In the figure, a goniometer base 2 placed on a frame 1
The sample support 3 is fixed thereon, and extends upward in the figure. On the upper part of the sample support 3, a substantially cylindrical sample stage 4 is provided. As shown in FIG. 2, the sample stage 4 is located on the near side of the sample support 3 (the lower side in FIG. 2). ).

In FIG. 2, a detector arm 5 extending from the rear of the sample table 4 is disposed on the left side of the sample table 4. on the other hand,
On the right side of the sample table 4, a source arm 6 that extends from the rear of the sample table 4 is also arranged. In the detector arm 5,
As shown in FIG. 1, a scattering prevention slit 7, a light-receiving-side solar slit 8, a light-receiving slit 9, and an X-ray detector 10 as X-ray detecting means are fixedly mounted. A divergent slit 11 and an X-ray tube 12 as X-ray generating means are attached to the source arm 6. The divergence slit 11 is fixedly attached to the source arm 6, and the X-ray tube 12 is attached to the source arm 6 via a drive mechanism 13, as shown in FIG.

The drive mechanism 13 includes a slider 14 fixed to one side of the X-ray tube 12 and a screw block 15 integrated with the slider 14.
2, a focus adjustment pulse motor 16 (broken line) fixed to the back side of the source arm 6 in FIG. 2, and a feed screw 17 connected to the output shaft of the focus adjustment pulse motor 16. I have. The slider 14 is fitted to the source arm 6 so as to be freely movable in the direction perpendicular to the plane of FIG. The feed screw 17 is engaged with the screw block 15, and when the pulse motor 16 rotates, the screw block 15 is rotated.
15, the slider 14 moves in the direction perpendicular to the plane of FIG. 2 (AA 'direction in FIG. 1), and the X-ray tube 12 moves in the same direction accordingly.

In FIG. 2, a worm wheel 18 is fixedly attached to the source arm 6 on the back side of the sample table 4. The worm wheel 18 has a source-side pulse motor
A worm 20 fixed to the 19 output shaft is engaged.
The detector arm 5 has a rotating shaft 21 that penetrates the source-side worm wheel 18 on the back side of the sample table 4. I have. This worm wheel 22 has
Worm 24 fixed to the output shaft of detection side pulse motor 23
Are engaged.

The focus adjustment pulse motor 16, the source-side pulse motor 19, and the detection-side pulse motor 23 all operate based on a command from the control device 25. The X-ray intensity signal output from the X-ray detector 10 is input to the control device 25.

A sample holder packed with a sample is attached to the sample table 4 at the time of X-ray diffraction measurement, and an optical axis adjusting jig is attached at the time of optical axis adjustment described later. As shown in FIG. 3, the lower end of the sample table 4 is notched, and two spring pieces 26, 26 are fixed to the notch. The sample holder 31 or an optical axis adjustment jig 27 described later
As shown by the arrow, it is inserted between the spring piece 26 and the sample table 4, and is held on the sample table 4 by the spring force of the spring piece 26. FIGS. 1 and 2 show a state where the sample holder 31 or the optical axis adjusting jig 27 is mounted on the sample table 4 by a chain line.

The X-ray diffraction measurement will be briefly described as follows.

In FIG. 1, first, a sample holder 31 packed with a sample is mounted on a sample table 4. Driven by the source-side pulse motor 19, the source arm 6 rotates .theta. At a predetermined step angle and step time. On the other hand, driven by the detection side pulse motor 23, the detector arm 5 is rotated by θ at the same step angle and step time in synchronization with the source arm 6. While the source arm 6 and the detector arm 5 rotate by θ in synchronization with each other, the X-ray tube 12 and the X-ray detector 10 fixed to each arm also rotate by θ in synchronization with each other. During the θ rotation, the X-rays emitted from the X-ray focal point B on the target 30 in the X-ray tube 12 pass through the divergence slit 11 and the sample 32 (second second sample) in the sample holder 31 mounted on the sample stage 4. (Fig.)
And diffracted here, and the diffracted X-rays enter the X-ray detector 10 through the scattering prevention slit 7, the light-receiving side solar slit 8, and the light-receiving slit 9, and the X-ray intensity is measured by the detector. Is done. Thereby, an X-ray diffraction pattern of the sample 32 is obtained.

In order to accurately set the angle of θ rotation for the X-ray tube 12 and the X-ray detector 10, the X-ray detector
It is necessary that the optical axis of the X-ray arriving at 10 and the surface of the sample (hereinafter, referred to as the sample surface) are always adjusted to certain conditions. In this embodiment, the optical axis adjustment step includes three consecutive steps of an X-ray focus adjustment step, a sample reference plane adjustment step, and an adjustment confirmation step. Hereinafter, each of those steps will be described.

(1) X-Ray Focus Adjustment Step This step is performed to adjust the X-ray focus B on a straight line connecting the X-ray detector 10, the light receiving slit 9, and the divergence slit 11. In performing this step, the sample stage 4
Do not attach anything.

First, as shown in FIG. 1, the source side pulse motor 19 is operated to set the source arm 6 to θ = 0 (horizontal position). Further, the detection side pulse motor 23 is operated to set the detector arm 5 to θ = 0 (horizontal position). Thus, the X-ray focal point B and the X-ray detector 10 in the X-ray tube 12 are arranged at positions symmetrical to each other with respect to the sample arrangement position, that is, the sample stage 4.

In this state, the X-ray detector 10, the light receiving slit 9, and the diverging slit 11 are located on a straight line. this is,
This is because such adjustment is made in advance in the manufacturing stage. However, in this case, the X-ray focal point B in the X-ray tube 12 is not always on the straight line. Therefore, the control device 25 (FIG. 2) controls the focus adjusting pulse motor 16.
Is rotated slightly, the X-ray intensity detected by the X-ray detector 10 at that time is read, and the movement of the focus adjusting pulse motor 16 and therefore the X-ray tube 12 is stopped at the position where the X-ray intensity is maximized.

By the above operation, the X-ray detector 10, the light receiving slit 9,
Then, the X-ray focal point B is set on the straight line connecting the divergence slits 11, and the process proceeds to the next sample reference plane adjustment step.

(2) Sample Reference Plane Adjustment Step This step is performed to set a zero reference position of the X-ray incident angle θ on the sample.

First, as shown in FIG.
Attach 27. As shown in FIGS. 4 and 5, the optical axis adjusting jig 27 is entirely formed in a thin flat plate shape, and has reference projections 28a and 28b formed on both side edges thereof.
A standard material, for example, silicon (Si) powder 29 is packed between the reference protrusions 28a and 28b. Reference projection
The surfaces C of the surfaces 28a and 28b and the surface C of the Si powder 29 are made extremely smooth by mirror finishing or the like, and the surfaces C (hereinafter referred to as reference surfaces) are included in the same surface. .

When the optical axis adjustment jig 27 is mounted on the sample stage 4, the control device
By means of 25 (FIG. 2), the source-side pulse motor 19 and the detection-side pulse motor 23 are slightly rotated in the same direction by exactly the same angle in synchronization with each other. As a result, the X-ray focal point B, the divergence slit 11, the light receiving slit 9, and the X-ray detector 10 rotate around the sample table 4 while maintaining the state of being on a straight line. As a result, the X-ray focus B
The X-ray traveling path reaching the X-ray detector 10 from above can be rotated about the sample stage 4.

An X-ray intensity signal is sent from the X-ray detector 10 to the control device 25 while the X-ray traveling path rotates as described above. When the X-ray intensity reaches a maximum, the control device 25 rotates the X-ray traveling path, and thus the X-ray focal point B and the X-ray detector.
Stop 10 rotations. The point at which the X-ray intensity detected by the X-ray detector 10 becomes maximum is that the reference plane C of the optical axis adjusting jig 27 is positioned with respect to the X-ray traveling path (chain line) as shown in FIG. This is equivalent to the case where they are exactly parallel.

In this state, if the sample holder 31 packed with the measurement sample is mounted on the sample table 4 instead of the optical axis adjustment jig 27, when the X-ray focus B is at the position of θ = 0, the X-ray focus B is radiated from there. The angle θ at which the X-rays are incident on the sample is set exactly to zero.

Although the X-ray optical axis has been set to the predetermined reference state by the above two steps, the following adjustment confirmation step is executed for further accuracy.

(3) Adjustment Confirmation Step In this step, the X-ray tube 12 and the X-ray detector 10 are rotated by θ at a predetermined step angle and a predetermined step time while the optical axis adjustment jig 27 is mounted on the sample table 4. Then, an X-ray diffraction pattern of the Si powder 29 packed in the optical axis adjusting jig 27 is obtained. The normal X-ray diffraction pattern for this Si powder is already well-known, and therefore, by comparing the X-ray diffraction pattern just obtained with the known X-ray diffraction pattern, the X-ray optical axis is obtained. Can be confirmed whether or not is set to the regular reference position.

As described above, the present invention has been described with reference to the preferred embodiments.
The present invention is not limited to the embodiment.

For example, in the above-described embodiment, the X-ray tube 12 and the X-ray detector 10 are automatically rotated and moved in the same direction by the same angle using the control device 25, but any other means may be used. The case in which the X-ray tube 12 and the X-ray detector 10 are moved synchronously by this is also included in the optical axis adjustment method according to the present invention.

[Effects of the Invention] According to the present invention, when the zero reference position of the X-ray incident angle θ to the sample is set (sample reference plane adjustment step), the X-ray generation means (X-ray tube 12) and the X-ray Detection means (X-ray detector
Adjustment is performed by rotating 10) synchronously in the same direction by the same angle. Since the adjustment is not performed by finely rotating the sample stage as in the related art, a complicated and expensive mechanism for finely rotating or clamping the sample stage is not required, and the cost is reduced. be able to.

According to the second aspect of the present invention, X is used for adjusting the optical axis.
The driving means for rotating and driving the X-ray generating means and the X-ray detecting means can be shared by the driving means for rotating the respective means for X-ray diffraction measurement, so that the structure can be further simplified. In addition, the optical axis adjustment procedure itself can be simplified.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a sample fixed X-ray diffractometer to which an optical axis adjusting method and apparatus according to the present invention is applied, FIG. 2 is a plan view according to arrow II in FIG. FIG. 3 is a side view showing a main part of the embodiment shown in FIG. 1, FIG. 4 is a perspective view showing an example of an optical axis adjusting jig, and FIG. FIG. 4 ... Sample table, 5 ... Detector arm, 6 ... Source arm, 10 ...
X-ray detector, 12: X-ray tube, 18: source-side worm wheel, 19: source-side pulse motor, 20: source-side worm, 21
... Detector rotation shaft, 22 ... Detection worm wheel, 23 ... Detection pulse motor, 24 ... Detection worm, 25 ... Control device, 32 ... Sample

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 23/20-23/207

Claims (2)

(57) [Claims] An optical axis used in a fixed sample X-ray diffractometer for measuring the intensity of X-ray diffracted on a sample surface while rotating an X-ray generation means and an X-ray detection means around a fixed sample. In the adjustment method, by rotating the X-ray traveling path from the X-ray generation means to the X-ray detection means around the sample arrangement position,
An optical axis adjusting method, comprising adjusting a sample surface and an X-ray traveling path to be parallel. 2. An optical axis adjustment used in a fixed sample X-ray diffractometer for measuring the intensity of X-ray diffracted on the sample surface while rotating the X-ray generation means and the X-ray detection means around the fixed sample. In the apparatus, a source-side drive unit that rotationally drives the X-ray generation unit around the sample arrangement position, a detection-side drive unit that rotationally drives the X-ray detection unit around the sample arrangement position, a source-side drive unit, and Control means for controlling the operation of the detection-side driving means, wherein the X-ray generation means and the X-ray detection means can be arranged at positions symmetrical to each other with respect to the sample arrangement position. The X means are arranged at symmetric positions with respect to each other.
An optical axis adjusting device for controlling the operation of the source-side driving unit and the detection-side driving unit such that the line generating unit and the X-ray detecting unit synchronously rotate and move in the same direction by the same angle. .