JP3168902B2 - X-ray diffractometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diffractometer provided with a rotary sample stage on a goniometer for rotatably holding a sample in the plane of the sample.

[0002]

2. Description of the Related Art An X-ray diffractometer irradiates an X-ray from an X-ray source to a sample placed at the center of the goniometer's θ-axis, and an X-ray detector fixed to the 2θ-axis of the goniometer moves around the sample. The intensity of the diffracted X-rays emitted from the sample is measured while rotating, and the qualitative and
It is a device that performs quantitative analysis.

When analyzing a powdery sample with this X-ray diffractometer, a powder sample is packed in a sample filling hole formed in a plate-like sample holder, and the sample is placed on a sample table installed at the center of the goniometer θ axis. Attach and rotate the X-ray detector around the sample to measure the diffraction pattern. However, in a powder sample with insufficient mixing or large individual crystal grains, the number of crystal grains contributing to the generation of diffraction rays in one direction decreases and the diffraction X-ray intensity decreases. There is a problem of including errors. In such a case, a rotating powder sample stage is used for the purpose of rotating the sample at a relatively high speed in the sample plane to increase the number of crystal grains contributing to diffraction.

On the other hand, when analyzing an oriented sample, a fibrous sample, or the like, incident light on a fixed sample stage depends on how the sample holder is packed into the sample holder and how the sample holder is mounted on the sample stage. Since the direction of the sample with respect to the detection direction of X-rays and diffraction X-rays changes, diffraction X-rays that should be originally detectable may not be obtained clearly. In such a case, by rotating the sample, the direction of the sample with respect to the detection direction of the incident X-ray and the diffracted X-ray is changed, and the sample is rotated in the sample plane so that the diffracted X-ray can be detected clearly. A fiber sample stage that changes direction is used.
Normally, on this fiber sample stage, the X-ray from the X-ray tube comes from the back of the sample.
Irradiation is performed to detect diffracted X-rays transmitted through the sample. At this time, a collimator that regulates the direction and irradiation width of the irradiated X-rays is installed near the X-ray emission port of the X-ray tube, and the optical axis is set in advance so that the narrowed X-rays are irradiated on the thin fibrous sample. It is necessary to make adjustments.

As described above, the measurement method is different between the powder sample and the fibrous sample, and accordingly, the sample table used is of a different type. That is,
In measurement of a powder sample, a goniometer is usually driven in conjunction with θ-2θ to measure a diffracted X-ray in a direction reflected from the sample surface. On the other hand, in the measurement of the fibrous sample, the θ rotation for rotating the sample surface is not performed, but the X-ray is fixedly irradiated from the back of the sample, and the 2θ rotation for rotating only the detector around the sample is performed. The diffraction X-ray transmitted through the sample is detected. Conventionally, the rotating powder sample table used for powder samples is designed only for the reflection method measurement, and a motor for rotation is arranged behind the sample, so the sample for performing the transmission method is It could not be used as a stand. Therefore, conventionally, the rotating powder sample stage and the fiber sample stage have been prepared as separate accessories of the X-ray diffraction device.They are attached to the goniometer in each case according to the sample to be analyzed, and the optical axis is adjusted and used for analysis. Was.

[0006]

As described above, in the conventional X-ray diffractometer, a rotating powder sample stage and a fiber sample stage are separately prepared. Since a sample is often analyzed, a rotating powder sample stage is usually mounted on a goniometer. Therefore, when analyzing a fibrous sample or the like, it is necessary to replace the sample table with a dedicated fiber sample table each time, which requires much time and effort. In addition, when the sample stage is replaced with a fiber sample stage, it is necessary to adjust the optical axis of the collimator for narrowing the X-ray from the tube each time. These tasks were very cumbersome.

The present invention has been made in view of such circumstances, and has a rotating sample stage that combines the functions of a rotating powder sample stage and a fiber sample stage and eliminates the need for optical axis adjustment. It is an object of the present invention to provide an X-ray diffraction apparatus.

[0008]

According to the present invention, there is provided an X-ray diffractometer having a rotating sample stage having a mechanism for rotating a sample in the plane of the sample. A rotating shaft part having a space through which the irradiated X-rays can pass and rotating the sample; and a collimator comprising a member having small holes fixed at the rear end and the front end of the rotating shaft part, and a light formed by the collimator. The axis is coincident with the rotation axis.

The X-ray diffractometer of the present invention is configured as described above, is provided with a mechanism for rotating the sample in the plane of the sample, and the irradiation X-ray passes through the center of the rotating shaft for rotating the sample. A space is made and a collimator with an optical axis coinciding with the rotation axis is built in by inserting a member with a small hole into this rotation axis part.For powder samples, irradiate X-rays from the surface of the sample. Diffraction X-rays can be measured by a reflection method, and a fibrous sample can be measured by a transmission method by irradiating the sample with X-rays from the back. Further, since the collimator is built in a state adjusted in advance, the optical axis adjustment of the collimator, which is conventionally required, becomes unnecessary.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a rotating sample stage which is a main part of the X-ray diffraction apparatus of the present invention.

The rotating sample table 1 is supported by bearings 6 so that the shaft 4 can rotate with respect to the bracket 13. The sample holder holder 5 is connected to the tip of the shaft 4, and the sample holder 17 is detachably mounted on the sample holder holder 5. A pulley 7 is attached to the shaft 4, which is connected to a stepping motor 11 by a timing belt 12, and the shaft 4 is rotated by driving the stepping motor 11. When the stepping motor 11 is continuously driven, the sample holder rotates continuously. When the stepping motor 11 is driven by a certain angle, the sample holder is also tilted by a certain angle according to the angle. It is held in that position by the torque. A disk 8 having a slit for transmitting light is attached to the rear end of the shaft portion 4, and the slit 9 is detected by a sensor 9 including an LED and a phototransistor and used as an origin of rotation.

These components are fixed on a bottom plate 2 having a projection 3 at the center via a bracket 13,
The positional relationship is such that the central axis of the projection 3 and the surface of the sample holder 17 coincide. The projection 3 attached to the bottom plate 2 fits into a fitting hole provided at the center of a goniometer (not shown), and the central axis of the projection and the surface of the sample held by the sample holder 17 are moved by the goniometer. And the rotation axis 16 of the motor.

At the center of the shaft portion 4, there is provided a space through which a through hole is formed in the axial direction and through which irradiation X-rays can pass, and a collimator 10 is built in. A member having a small hole fitted in the rear end and the front end of the shaft portion 4 functions as a collimator, and limits the X-rays 14 generated in the tube so that the X-rays 14 are emitted to the center of the sample. At this time, the optical axis 15 through which the X-ray passes coincides with the central axis of the shaft portion 4, that is, the rotation axis.

As shown in FIG. 2, a sample holder 17 having a shape suitable for the type of the sample, such as a powder sample and a fibrous sample, is used. FIG. 2A shows a holder for a powder sample, in which a circular or square hole is made in the center of a plate having a predetermined size and thickness, and the hole is filled with a powder sample 21. The sample may be filled on a flat glass plate or the like so that the surface of the powder sample matches the surface of the sample holder plate. FIG. 2 (b) shows a holder for a fibrous sample. The sample is placed at the center by sandwiching both ends of the fibrous sample between sandwich plates provided above and below a central space of a plate having a predetermined size and thickness. The fibrous sample is fixed and the upper end is pulled by a screw mechanism to make the fibrous sample stretched. Each of these sample holders can be mounted on the sample holder holder 5 of FIG. 1, and the sample surface is aligned with the goniometer rotation axis 16 in this state.

Next, a method for measuring diffracted X-rays by the reflection method and the transmission method according to the type of the sample using the X-ray diffraction apparatus of the present invention will be described. 3 and 4, an X-ray tube 31 is a source of X-rays and generates primary X-rays for irradiating a sample. The goniometer 34 is of a type in which the θ axis and the 2θ axis can be driven independently, the rotating sample stage 33 is fixed to the center of the goniometer 34, that is, the θ axis, and can freely rotate θ, and the detector 35 is a goniometer. It is fixed to the 2θ axis and can rotate around the sample. The surface of the sample holder attached to the rotating sample table 33 is positioned at the center of rotation of the goniometer, and primary X-rays from the X-ray tube are emitted toward the sample at the center of rotation. In this state, the qualitative and quantitative analysis of the sample is performed by measuring the diffraction angle and intensity of the diffracted X-rays emitted in various directions by the sample while rotating the detector 35 (2θ axis). Can be. Note that FIGS. 3 and 4 illustrate a so-called vertical goniometer in which the rotation surface of the goniometer is arranged so as to stand in the vertical direction.
It goes without saying that a horizontal goniometer that is arranged so that the rotation surface is horizontal may be used.

FIG. 3 is a diagram for explaining an arrangement of a reflection method used for measuring a powder sample. The powder sample is filled in a powder sample holder as shown in FIG. 2A, and the sample holder is mounted on the rotating sample table 33 as described in FIG. The rotating sample stage 33 is rotated by the goniometer θ-axis to an angle at which the surface of the sample is irradiated with the X-rays 36, and the primary X-rays 36 from the X-ray tube 31 are irradiated from the surface direction of the sample, Diffracted X-rays emitted in a direction reflected from the surface are detected by a detector 35. At the time of measuring the diffracted X-ray, the rotating sample stage 33 and the detector 35 are rotationally scanned about the central axis of the goniometer as indicated by arrows A and B in a so-called .theta.-2.theta. At the time of this measurement, if necessary, the powder sample holder 37 is rotated at a relatively high speed in the sample plane by a sample rotating mechanism provided on the rotating sample stage 33, for example, because the sample particles are coarse. By doing this, X
The number of particles contributing to line diffraction increases, and a smooth diffraction pattern can be obtained. It is preferable that the rotation speed in the sample plane be as high as possible, but some rotation speeds may be selected according to the scanning speed of the detector 35 and the like.

On the other hand, FIG. 4 is a view for explaining the arrangement of the transmission method used for a fiber sample. In this arrangement, the rotating sample stage 33 has the built-in collimator 39 and the X-ray tube 31
The anti-scatter slit 32 is fixed so as to face the line generation point.
And the X-ray 36 passing through the collimator 39 is irradiated from behind the fibrous sample attached to the fiber sample holder 38,
The X-ray diffracted by the sample is detected by the detector 35. During measurement of the diffracted X-ray, the θ axis of the goniometer is not moved (that is, the rotating sample stage 33 is fixed as described above), and the detector 35 on the 2θ axis is centered on the central axis of the goniometer as indicated by arrow B. Is rotationally scanned. At the time of this measurement, if necessary, the fiber sample holder 38 is rotated to a required angle in the sample plane by a rotation mechanism provided on the rotary sample table 33, and fixed at that position.

In the case of measuring a fiber sample as shown in FIG. 4, it is necessary to narrow down the irradiated X-rays using a collimator so that the irradiated X-rays can be exactly irradiated onto the thin fiber sample. In this rotary sample table, the collimator is built in the rotary sample table and axis adjustment is completed in advance, so that it is not necessary to adjust the collimator again when measuring the fiber sample.

[0019]

The rotating sample stage provided in the X-ray diffraction apparatus of the present invention has a mechanism for rotating the sample in the sample plane, and has a space through which the irradiated X-ray can pass at the center of the rotating shaft. Opening a collimator with an optical axis coinciding with the rotation axis by inserting a member with a small hole into the rotation axis part, the powder sample is irradiated with X-rays from the sample surface by the reflection method. Diffracted X-rays can be measured, and a fibrous sample can be measured by a transmission method by irradiating the sample with X-rays from the back. Therefore, whether the sample is a powder sample or a fibrous sample, there is no need to replace the sample table, and the goniometer θ
It is no longer necessary to set the origin of the angle. Further, since the collimator is incorporated in a state adjusted in advance, the optical axis adjustment of the collimator, which is conventionally required when measuring a fibrous sample, is not required. That is, according to the present invention,
By providing one rotating sample stage, it is possible to provide an X-ray diffraction apparatus having the functions of the rotating powder sample stage and the fiber sample stage, and a remarkable effect that the adjustment work is hardly required.

[Brief description of the drawings]

FIG. 1 is an embodiment of a rotating sample stage which is a main part of an X-ray diffraction apparatus of the present invention.

FIG. 2 is an example of a sample holder used for a rotating sample stage of the present invention.

FIG. 3 shows the diffraction X by the reflection method using the X-ray diffraction apparatus of the present invention.
An arrangement for measuring lines.

FIG. 4 shows a diffraction X by a transmission method using the X-ray diffraction apparatus of the present invention.
An arrangement for measuring lines.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... rotating sample stand, 2 ... bottom plate, 3 ... projection, 4 ... shaft part, 5 ...
Sample holder holder, 6 ... Bearing, 7 ... Pulley, 8
... Disc, 9 ... Sensor, 10 ... Collimator, 11 ... Stepping motor, 12 ... Timing belt, 13 ... Bracket, 14 ... X-ray, 15 ... Optical axis, 16 ... Goniometer rotation axis, 17 ... Sample holder, 31 ... X-ray Tube, 32: X-ray scattering prevention slit, 33: Rotating sample table, 34: Goniometer, 35: Detector, 36: X-ray, 37: Powder sample holder, 38: Fiber sample holder, 39: Collimator

Continuation of the front page (56) References JP-A-7-225201 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 23/00-23/227

Claims (1)

(57) [Claims] 1. An X-ray diffractometer having a rotating sample stage having a mechanism for rotating a sample in the plane of the sample, a rotating shaft for rotating the sample, the center of which has a space through which irradiation X-rays from behind can pass. And a collimator formed of a member having a small hole fixed to the rear end and the front end of the rotating shaft portion, and an optical axis formed by the collimator coincides with the rotating axis. Line diffractometer.