JPS6342739B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray goniometer, and particularly to an X-ray goniometer suitable for detecting minute differences in lattice constants.

Even if the substances are the same, their lattice constants may differ slightly if the temperature or pressure during the formation process is different, or if the amount of trace elements mixed is different. When attempting to measure such minute differences in lattice constants, conventionally the first of two powder samples whose lattice constants are thought to differ by a minute amount from each other is first placed on a sample mounting plate. (holder) and scan the goniometer to obtain a profile of the characteristic X-ray intensity diffracted by a specific crystal reflecting surface of the sample, and then calculate the Bragg angle θ of the first type sample from the profile. ₁ and calculate the lattice constant of the sample. Similarly, a second type of sample is mounted on the sample mounting plate and the goniometer is scanned to obtain a characteristic X-ray intensity profile. From the peak value of this profile, the second type of sample is The lattice constant of the seed sample is calculated and compared with the already determined lattice constant of the first type sample.

However, in scanning with a goniometer, it is inevitable that a slight mechanical error will be introduced each time the goniometer rotates. Furthermore, the method of attaching the sample mounting plate to the rotating shaft of the goniometer is slightly different each time. Therefore, the measurement for determining θ ₁ and the measurement for determining θ ₂ described above cannot be performed under the same conditions or under conditions close to the same, and the slight difference between the lattice constants of two similar samples cannot be performed. cannot be determined accurately.

The present invention solves these conventional drawbacks and provides an X-ray goniometer that can accurately measure the difference in lattice constants.The present invention will be described in detail below with reference to the drawings.

In FIG. 1 showing an embodiment of the present invention, 1 is a substrate, and a cylinder 2 is fixed on the substrate 1. As shown in FIG. The cylinder body 2 receives X-rays 3 from an X-ray source not shown.
It has a notch 4 through which X-rays pass, and a notch 5 through which X-rays diffracted by the sample pass. A disk 6 is rotatably attached to the top of the cylinder 2 by means of a bearing 7. A second cylindrical body 8 is attached to the disc 6. A first slit 9 is formed in the second cylindrical body 8, and second and third slits 10a and 10b are provided at positions 180° apart from the first slit 9. .
Reference numeral 11 denotes a rotating shaft, and the tip of the rotating shaft 11 is notched, and the sample mounting plate 1 is placed in the notched portion.
2 is pressed by a leaf spring 13 and attached. As shown in an enlarged view in FIG. 2, the sample mounting plate 12 is divided into first, second, and third mounting areas A, B, and C arranged along the direction of the rotation axis 11. , second and third regions B and C are symmetrically formed on both sides of the first region A. Each of these sample mounting areas has a depth of, for example, about 200 μm, and is formed in a band shape. For example, a heat-treated sample is mounted in the first sample mounting area A, and normal samples made of the same material as the sample and not subjected to heat treatment are mounted in the second and third areas B and C. 14 and 15 are the X scattered from the sample attached to each of these areas.
This is a shield plate to prevent wire interference. Further, the slit 9 and the slits 10a and 10b each allow the X-rays passing through the slit 9 to
The slits 10a, 10
The X-rays that have passed through b
Its size and position are determined so that only areas B and C are irradiated. Further, the rotating shaft 11 and the sample mounting plate 12 together with the rotating shaft 11 are rotated by 0.01° every 10 seconds, for example, by a step motor (not shown). As shown in FIG. 3, an X-ray detector 16, such as a scintillation detector, is provided to detect X-rays diffracted by the sample. The X-ray detector 16 synchronizes with the rotation of the shaft 11 at twice the rotation angle of the shaft 11 (every 0.02°).
The X-rays rotate and are reflected by the sample at various angles and enter the X-ray detector 16 . Also the first
Although it is not clear from the figure, the X diffracted from the sample
In order to guide the radiation to the X-ray detector 16, the portion of the cylinder 8 remote from the slits 9, 10a, 10b is cut out. The cylinder 2 is provided with a lid 17 to prevent leakage of X-rays. Reference numeral 18 denotes a support member attached to the substrate 1, and a step motor 19 is connected to the support member 18 to drive the rotary disk 6 through a shaft 20.
It is attached to rotate in 180° increments.

In the above-described configuration, the first sample mounting area A of the sample mounting plate 12 is filled with a sample that has undergone heat treatment, and the second and third areas B and C are made of the same material as the sample but are not heat treated. Usually, the plate 12 is attached after the sample is packed. Next, the sample packed in the first area A is irradiated with X-rays through the first slit 9, the diffracted X-rays at that time are detected by the X-ray detector 16, and the output of the detector is sent to a printer, for example. output to a display means such as . Next, the cylinder body 8 is rotated 180 degrees by the step motor 19, and the slits 10a, 10
The sample packed in the second and third areas is irradiated with X-rays through
6, and print out the detected signal value. Next, set the sample mounting plate 12 at an angle of 0.01° and the X-ray detector 1.
6 is rotated by 0.02 degrees, and the cylindrical body 8 is rotated by 180 degrees to irradiate the sample filled in the first area A with X-rays through the slit 9, and print by detecting the diffracted X-rays. Go out. Next, the cylinder 8 is rotated 180 degrees to irradiate the samples filled in the second and third regions B and C with X-rays through the slits 10a and 10b, and the X-rays are detected and printed out. do. Similarly, each time the angle of incidence of X-rays on the sample is increased by 0.01°, the diffracted X-ray intensity from the sample packed in the first region A and the packed in the second and third regions B and C The diffracted X-ray intensity from the sample is detected and printed out. In this way, by one rotation of the goniometer, the intensity profile g of X-rays diffracted by a heat-treated sample as shown in FIG. An intensity profile f is obtained. From these two intensity profiles, the difference in Bragg angles that give the highest intensity value can be determined, and from this difference, the difference in lattice constants can be determined.

Now, generally speaking, when the sample surface shown by the solid line SP is rotated around the axis shown by P in Fig. 5a and a profile shown by PP in Fig. 5b is obtained, the axes GA,
When the sample surfaces LA, LB, and LC are rotated around GB and GC to obtain a profile, the resulting profile shows the sample position displacement as shown by PA, PB, and PC, respectively, in Figure 5b.
, a proportional reflection angle displacement is obtained. by the way,
The sample mounting plate 12 may not be attached completely, or the manufacturing precision of the device may be insufficient.
As shown in FIG. 6, the mounting position of the sample mounting plate 12 may be inclined with respect to the central axis 21 of the cylinder 8. In such a case, if the lattice constants of the samples are the same, the X-rays diffracted by the sample attached to sample attachment area A of the sample attachment plate 12 and the samples attached to sample attachment areas B and C will be exactly as shown in Figure 5b. Profile in
The profile deviates from the regular profile PP, such as PA, PB, and PC. By the way, profile PB
The profile obtained by adding the and profile PC is
PBC, and its peak position is profile PA
matches the position of Therefore, in the apparatus of the present invention, even if the mounting position of the sample mounting plate is tilted with respect to the central axis 21 of the cylinder 8 due to the above-mentioned cause, the peak positions of the two types of samples are determined by this tilt. The difference will be the same amount, and when determining the difference between the peak positions of the profiles based on the two types of samples, the error due to the above-mentioned slope will be negligible.

Furthermore, in the device based on the present invention described above,
Since the necessary data can be obtained by simply attaching the sample mounting plate and rotating the goniometer once, errors that may occur due to incomplete reproducibility of attaching the sample mounting plate and rotating the goniometer are eliminated. The difference in lattice constants between two types of samples can be measured with great accuracy.

In the above-described embodiments, it is desirable to detect X-rays diffracted at a high angle in order to improve measurement accuracy.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an outline of an embodiment of the present invention, Fig. 2 is a diagram showing an enlarged view of the sample mounting plate, and Fig. 3 is a diagram explaining the rotation of the sample mounting plate and the X-ray detector. Figure 4 is a diagram to show an example of the obtained profile, and Figure 5 is a diagram to explain the relationship between the deviation of the axis for rotating the sample surface and the deviation of the obtained profile. , FIG. 6 is a diagram for explaining the sample mounting plate attached at an angle with respect to the central axis of the cylinder 8. 1: Substrate, 2, 8: Cylindrical body, 3: X-ray, 4, 5:
Notch, 6: Disc, 7: Bearing, 9, 10a,
10b: Slit, 11, 20: Rotating shaft, 12:
Sample mounting plate, 13: plate spring, 14, 15: shield plate, 16: X-ray detector, 17: lid, 18: support member, 19: step motor, 21: central shaft.

Claims (1)

[Claims] 1. A sample holding surface is provided on a sample holding shaft along the holding axis, and means for irradiating the sample holding surface with X-rays from a direction perpendicular to the sample holding axis is provided, The sample holding shaft is rotatable about its axis in order to change the angle of incidence with respect to the surface, and a detector for detecting characteristic X-rays diffracted from the sample as a result of irradiation with the X-rays is mounted on the sample holding shaft. In an X-ray goniometer that is rotatable about a holding shaft and is provided with means for rotating the sample holding shaft and the detector at an angular ratio of 1:2, the sample holding surface is It is divided into first, second, and third regions arranged along the direction of the holding axis, and the second and third regions are located on both sides of the first region with the first region as the center. A slit plate having one slit for selectively irradiating the first region with the X-rays and two slit plates arranged symmetrically with each other for selectively irradiating the second and third regions with the X-rays. An X-ray goniometer characterized by comprising means for switching between a slit plate having a plurality of slits and arranging the slit plate on the X-ray optical path.