JP2761447B2 - 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 diffraction apparatus which stores an X-ray diffraction image of a sample on a radiation image storage plate and obtains X-ray diffraction information of the sample by reading the image. is there.

[0002]

2. Description of the Related Art Various X-ray diffraction apparatuses have been developed which accumulate an X-ray diffraction image of a crystalline sample on a radiation image storage plate and obtain the X-ray diffraction information of the sample by reading the image. ing. In this type of X-ray diffractometer,
A sample held rotatably by an X-ray goniometer is irradiated with X-rays emitted from an X-ray source. At this time, diffracted X-rays from the sample are stored on a radiation image storage plate arranged at a predetermined position (image storage position). Thereafter, the radiation image storage plate whose storage has been completed is set at an image reading position in the radiation image reading apparatus, and the stored image is read.

Incidentally, this type of X-ray diffractometer initially has only one radiation image storage plate, and when one image storage is completed, the stored image is read and stored. There is a disadvantage that the next image accumulation work cannot be started until the image is erased.For example, when time-resolved analysis of a crystal is performed on a sample whose crystal form changes every moment, the time Certain limits have been placed on improving the resolution.

Therefore, in order to solve such a defect, an X-ray diffraction apparatus shown in FIGS. 2 and 3 has been conventionally proposed. This X-ray diffractometer is disclosed in Japanese Patent Application Laid-Open No. 3-57947. The X-ray goniometer 2 rotatably holds the sample 1 to change the X-ray irradiation direction on the sample 1; Two radiation image storage plates 31 and 32 for storing an X-ray diffraction image generated from the sample when the sample is irradiated with X-rays;
A radiation image reading device 4 for reading the radiation image stored in the radiation image storage device 32, and moving one of the two radiation image storage plates 31 and 32 to the image storage position and reading the other image by the radiation image reading device 4 And a moving mechanism 5 for moving to a position. The arrow X in the figure
Indicates an incident X-ray.

Here, the radiation image storage plates 31, 32
Have a substantially arc-shaped plate shape. 2 and 3, the position where the first radiation image storage plate 31 exists is the image storage position, and the position where the second radiation image storage plate 32 exists is the image reading position. .

The first radiographic image storage plate 31 is provided with a first moving table 51 screwed to a first screw rod 51 of the moving mechanism 5.
The first screw rod 51 rotates to reciprocate linearly between the image storage position and the image reading position. On the other hand, the second radiation image storage plate 32 is mounted on an auxiliary moving table 32a, and the auxiliary moving table 32a is mounted on a second moving table 52c screwed to the second screw rod 52. The second screw rod 52 is provided in parallel with the first screw rod 51 described above. Further, the auxiliary moving table 32a includes a second moving table 52.
c, and is screwed into the screw rod 52g mounted on the second moving table 52c by the rotation of the screw rod 52g in a direction orthogonal to the moving direction of the second moving table 52c (the axial direction of the second screw rod 52). It is possible to advance and retreat linearly. With such a configuration, the second radiation image storage plate 32 reciprocates in the axial direction of the second screw rod 52 (that is, the direction in which the image storage position and the image reading position are arranged), and Advancing and retreating in a direction perpendicular to the axis of the screw rod 52 is enabled. By performing a moving operation by combining these moving operations, the position can be switched without colliding with the first radiation image storage plate 31. it can.

Although not described in detail, the radiation image reading device 4 is of a type that emits excitation light and detects emitted light from the tip of a rotary probe 41 rotatably mounted on a reading device main body 42. It is.

[0008]

In the conventional X-ray diffraction apparatus shown in FIGS. 2 and 3, first, the first radiation image storage plate 31 is positioned at the image storage position, and
The radiation image storage plate 32 is positioned at the image reading position. Then, in this state, the X-ray diffraction image is stored in the first radiation image storage plate 31.

When the accumulation of the X-ray diffraction image is completed,
The positions of the first and second radiation image storage plates 31 and 32 are exchanged with each other, and this time, the second radiation image storage plate 3
2, the X-ray diffraction image stored in the first radiation image storage plate 31 is read by the radiation image reading device 4.

When the storage of the X-ray diffraction image in the second radiation image storage plate 32 and the reading of the X-ray diffraction image from the first radiation image storage plate 31 are completed, the respective radiation image storage is performed again. The positions of the plates 31 and 32 are switched, and X
The accumulation of the X-ray diffraction image and the reading of the X-ray diffraction image are repeated.

By repeating the above operations one after another, when one X-ray diffraction image accumulating operation is completed, the reading of the next X-ray diffraction image can be immediately performed without waiting until the reading of the stored image is completed. The operation can be shifted to the accumulation operation, so that extremely efficient measurement can be performed. For example, a remarkable improvement in the time resolution in time-resolved analysis measurement of a crystal can be expected.

However, in the case of the X-ray diffraction apparatus shown in FIGS. 2 and 3, two radiation image storage plates 31 and 32 are arranged on the same surface while being separated from each other in a direction along the surface of the storage plate. Therefore, the moving mechanism 5 for moving and operating each of the radiation image storage plates 31 and 32 reciprocates the radiation image storage plates over a length of three or more radiation image storage plates as shown in the figure. A mechanism (screw rods 51, 52, guide rails, etc.) and a mechanism (screw rod 52g, guide rails, etc.) for reciprocating one of the radiation image storage plates in a direction perpendicular to the surface are required. As the moving mechanism 5 becomes larger, the configuration of the moving mechanism 5 becomes more complicated, and accordingly, it becomes difficult to obtain accuracy when the radiation image storage plate is moved to the image reading position or the image storage position, and the reproducibility of the position is improved. Difficult to improve There is a problem that becomes.

Further, since only two radiation image storage plates can be handled, it cannot be used for diffraction measurement that requires measurement of a large number of diffraction images without a time interval. There was also a problem that the use of this was limited.

In the X-ray diffraction measurement, Weissenberg measurement for measuring the diffraction line in relation to the orientation of the sample or the like is often required, but such a moving mechanism 5 realizes such Weissenberg measurement. It is also impossible to perform the measurement, and there is also a problem that the use of the diffraction measurement is limited.

The present invention has been made in view of the above circumstances, and reproduces the position of a radiation image storage plate during a moving operation by simplifying a moving mechanism for moving the radiation image storage plate to an image storage position and an image reading position. Performance, and it is possible to accumulate a large number of X-ray diffraction images continuously, and at the same time, it is possible to perform Weissenberg measurement,
An object of the present invention is to provide an X-ray diffractometer in which the use of diffraction measurement is greatly expanded.

[0016]

An X-ray diffractometer according to claim 1 comprises an X-ray goniometer which rotatably holds a sample in order to change an X-ray irradiation direction on the sample, and an X-ray goniometer for applying X-rays to the sample. A plurality of radiation image storage plates for storing an X-ray diffraction image generated from the sample when irradiated; a moving mechanism for moving the plurality of radiation image storage plates to an image reading position or an image storage position; And a radiation image reading device for reading a radiation image from a radiation image storage plate set at the image reading position by the moving mechanism.

The moving mechanism holds the plurality of radiation image storage plates at positions on the turntable that are on the same circumference as the rotation center of the turntable, and adjusts the rotation amount of the turntable. By controlling, an arbitrary radiation image storage plate is moved to an image storage position or an image reading position.

Further, the radiation image reading apparatus includes a reading arm, an arm driving means, and a motor for rotating a storage plate. The reading arm has a shaft support rotatably supported by a rotation center of the turntable. An arm protruding from the pivot portion in the radial direction of the turntable, and the distal end of the arm irradiates the radiation image storage plate with excitation light and irradiates the excitation light onto the radiation image storage plate. An optical unit for receiving the generated light is provided.

Further, the arm drive means is configured to rotate the shaft support with respect to the turntable by supplying power from a drive source mounted on the turntable, and the storage plate rotating motor is used for scanning for reading. Then, the radiation image storage plate located at the image reading position is rotated at the holding position on the rotary table.

According to a second aspect of the present invention, there is provided an X-ray diffractometer which further embodies the X-ray diffractometer according to the first aspect, wherein the moving mechanism includes a worm meshed with a worm wheel fixed to a turntable. Is used to control the amount of rotation of the turntable.

Further, the arm driving means is configured to rotationally drive the worm wheel fixed to the shaft support portion by using a worm mounted on a worm wheel fixed to a rotary table as a driving source.

[0022]

In the X-ray diffraction apparatus according to the first aspect, the moving mechanism for moving the radiation image storage plate to the image reading position and the image storage position includes a plurality of radiation image storage plates on the same circumference of the turntable. In this arrangement, the operation of moving the radiation image storage plate to the image reading position and the image storage position is realized only by controlling the rotation amount of the turntable. Therefore,
The moving mechanism can be simplified by the adoption of a rotary motion mechanism with a simple structure, making it easier to obtain accuracy when moving to the image reading position and image storage position, and improving the reproducibility of the position when moving. Can be done.

Further, in the X-ray diffraction apparatus according to the first aspect, while the radiation image storage plate at the image reading position is rotated by the storage plate rotation motor, the tip of the reading arm has a radius on the radiation image storage plate. By rotating the reading arm relative to the turntable so as to cross in the direction, it is possible to read and scan the entire area of the radiation image storage plate. Since only a simple rotational movement is required for the movement operation, the simplification of the drive mechanism can be spread to the entire apparatus in combination with the above-described movement mechanism, and excellent in both image storage processing and image reading processing. Position repeatability can be ensured.

Moreover, it is possible to arrange three or more radiation image storage plates on the rotary table, so that a large number of X-ray diffraction images can be stored continuously.

Further, by causing the rotary table to reciprocate in a minute angle range, a swinging motion can be given to the radiation image storage plate located at the image storage position. Therefore, in synchronization with the rotation of the sample by the X-ray goniometer, by giving a swinging motion to the radiation image storage plate, it becomes possible to perform Weissenberg measurement that measures diffraction lines in association with the orientation of the sample, When combined with the convenience of increasing the number of radiation image storage plates to three or more, the radiation image storage plate can be used for various diffraction measurements.

The X-ray diffractometer according to claim 2 is
A rotation transmission mechanism using a combination of a worm and a worm wheel is used as a driving means of the turntable or the reading arm. With such a mechanism, high movement accuracy can be achieved with a simple configuration having a small number of parts. Therefore, it is possible to relatively easily obtain the above-described improvement in the reproducibility of the position.

[0027]

1 and 4 show an embodiment of an X-ray diffraction apparatus according to the present invention. The X-ray diffractometer according to this embodiment includes an X-ray goniometer 2 that rotatably holds the sample 1 to change the X-ray irradiation direction on the sample 1.
And two radiation image storage plates 11 and 12 for storing an X-ray diffraction image generated from the sample 1 when the sample 1 is irradiated with X-rays, and these radiation image storage plates 11 and 12
A moving mechanism 20 for moving the image to the image reading position or the image storing position, and a radiation image reading device 60 for reading a radiation image from the radiation image storage plates 11 and 12 set at the image reading position by the moving mechanism 20. It is a configuration provided. Note that an arrow X in the figure indicates an incident X-ray, and a reference numeral 70 indicates an X-ray generator.

Here, the sample 1 is a crystalline sample, and may be, for example, a covaloxime complex whose crystal form changes every moment. The X-ray goniometer 2 may be a known one.

Each of the first radiation image storage plate 11 and the second radiation image storage plate 12 is formed by applying a radiation image storage material to the surface of a disk-shaped substrate. The entire surface on which is applied the radiation image storage surfaces 11a and 12a.

The radiation image storage plates 11, 1
When the radiation image accumulating substance applied to No. 2 is irradiated with radiation such as X-rays, the radiation image is accumulated as a latent image, and when the latent image is irradiated with predetermined excitation light, It has the property of emitting light corresponding to the latent image. The radiation image accumulating substance itself is a known substance.

The moving mechanism 20 includes a slightly elongated rotary table 21, and a cylindrical rotary table fixedly provided at the center of the rotary table 21 and rotatably supported by a support structure 22. A shaft 23, a worm wheel 24 concentrically fixed to the turntable shaft 23, a worm 25 meshing with the worm wheel 24 to rotationally drive the turntable 21, and a motor for driving the worm 25 26.

The rotary table 21 is provided at both ends on the same circumference with respect to the center of rotation.
1, 12 are held. However, the holding of the radiation image storage plates 11 and 12 on the turntable 21
The operation is performed via the storage plate rotating motors 27 and 28 fixed to the motor. These motors 27 and 28 rotate the radiation image storage plates 11 for reading and scanning during the reading process. Except when power is supplied to rotate the radiation image storage plates 11 and 12, the radiation image storage plates 11 and 12 are rotated. Have no force to regulate the rotation of the radiation image storage plates 11 and 12
Is in a freely rotatable state. Therefore, the radiation image storage plate 1
In order to prevent unnecessary rotation of the rotary tables 1 and 12, the turntable 21 is provided with a storage plate fixture 29. The storage plate fixing member 29 prevents rotation of the radiation image storage plates 11 and 12 by bringing a protrusion 29a, which is operated and retracted by a solenoid or the like, into contact with the outer peripheral portions of the radiation image storage plates 11 and 12.

In the case of this embodiment, the rotation center axis of the rotary table shaft 23 and the rotation center axes of the radiation image storage plates 11 and 12 are both set horizontally. Also,
The motor 26 is fixed to a support structure 22 that supports the turntable shaft 23. The moving mechanism 20 rotates the turntable shaft 23 by 180 ° according to the above-described configuration, so that the radiation image storage plate that has been located at the image storage position is located at the image reading position and is located at the image reading position. The radiation image storage plates, which have been used, replace the positions of the radiation image storage plates 11 and 12 with the image storage positions.

In FIG. 1, the position where the radiation image storage plate 11 is located is the image storage position, and the position where the radiation image storage plate 12 is located is the image reading position.

The rotation transmission mechanism using the combination of the worm wheel 24 and the worm 25 is also suitable for controlling a minute amount of rotation with high accuracy. In this embodiment, the sample transmitted by the X-ray goniometer 2 is used. The worm wheel 24 can be rotated forward and backward in a minute range in synchronization with the first rotation operation. The forward / reverse rotation operation of the worm wheel 24 realizes a rocking motion synchronized with the rotation of the sample 1 on the radiation image storage plates 11 and 12 supported on the turntable 21. Enables Weissenberg measurement to measure.

The radiation image reading apparatus 60 includes a reading arm 61, an arm driving means 62, the above-described motors 27 and 28 for rotating the storage plate, and a light source 6 for generating excitation light 63.
4, and a light emission detection device 65 for detecting light emission generated on the radiation image storage surface of the radiation image storage plate by irradiation of the excitation light 63.

Here, the reading arm 61 is inserted into the turntable shaft 23 and is rotatably supported at the center of rotation of the turntable 21. With the configuration including an arm portion 61b that protrudes in the radial direction, the tip of the arm portion 61b irradiates the radiation image storage plate with the excitation light 63 and generates the radiation image on the radiation image storage plate by irradiation with the excitation light. An aspheric lens 61c, which is an optical means for receiving the emitted light, is provided. Further, the shaft support 61a and the arm 61
b has a cylindrical shape and has a total internal reflection mirror 61d,
Optical elements such as 61e, a dichroic mirror 61f and a half mirror 61g are provided, and these optical elements provide a light guide path for the excitation light 63 and the emitted light.

The light source 64 is a so-called laser light source.
HeNe laser light is generated as the excitation light 63. The excitation light 63 generated by the light source 64 is applied to total reflection mirrors 66 and 6.
1d, dichroic mirror 61f, aspheric lens 61
The radiation image is irradiated on the radiation image storage surface via c. On the other hand, the emitted light is transmitted from the aspheric lens 61c to the dichroic mirror 61c.
The light is guided to the half mirror 61g via f. The half mirror 61g transmits or reflects according to the intensity of the emitted light, and the emitted light having a high intensity passes through the half mirror 61g and the first photomultiplier tube 65a located behind the half mirror 61g.
Is detected by The low-intensity emitted light is reflected by the half mirror 61g, and then detected by the second photomultiplier tube 65b via the total reflection mirror 61e.

These photomultiplier tubes 65a and 65b are
The first photomultiplier tube 65a, which constitutes the emission light detection device 65, has a high sensitivity suitable for detecting high-intensity emitted light, and the second photomultiplier tube 65b has low-intensity light emission. It is for low sensitivity suitable for light detection. In this way, by dividing the detection device according to the intensity of the emitted light, the dynamic range of the emitted light detection can be expanded, and the measurement ability is improved. The arm driving means 62 includes a worm 62a, a worm wheel 62b meshing with the worm 62a, and a motor 6 for driving the worm 62a.
2c and the like. Here, a motor 62c and a worm 62a serving as a driving source are attached to a worm wheel 24 fixed to the turntable 21. On the other hand, the worm wheel 62b is a shaft support 61a of the reading arm 61.
With such a configuration, rotation control of the reading arm 61 based on the turntable 21 is realized.

In the X-ray diffractometer of one embodiment as described above,
The operation of moving the radiation image storage plates 11 and 12 to the image reading position and the image storage position is realized only by controlling the rotation amount of the turntable 21. Therefore, as shown in the figure, by using a rotation transmission mechanism based on a combination of a worm and a worm wheel as a driving means of the turntable 21 and the reading arm 61, the image reading position and the image reading position can be reduced while having a simple configuration with a small number of components. It is easy to obtain the accuracy when moving to the image storage position, and it is possible to simplify the moving mechanism and the like, and to improve the reproducibility of the position during the moving operation.

Further, for example, while the radiation image storage plate 12 at the image reading position is rotated by the storage plate rotation motor 28, the tip of the reading arm 61 crosses the radiation image storage plate 12 in the radial direction. If the reading arm 61 is relatively rotated with respect to the turntable 21, the whole area of the radiation image storage plate 12 can be read and scanned.
At the time of the reading process, the movement required for the radiation image storage plate 12 and the reading arm 61 may be only a simple rotational movement. Therefore, the simplification of the driving mechanism is applied to the entire apparatus together with the moving mechanism 20 described above. Therefore, excellent reproducibility of the position can be ensured in both the image accumulation processing and the image reading processing.

Further, by causing the rotary table 21 to reciprocate in a minute angle range, a swinging motion can be given to the radiation image storage plate located at the image storage position. Therefore, as described above, the Weissenberg measurement for measuring the diffraction line in relation to the orientation of the sample or the like by giving the rocking motion to the radiation image storage plate in synchronization with the rotation of the sample 1 by the X-ray goniometer 2 is performed. And extend the applications of diffraction measurements.

Further, even when the rotating table 21 is swung and the Weissenberg measurement is performed, the reading arm 61 is positioned at the radiation image reading position because the reading arm 61 is positioned with respect to the rotating table 21. The positional relationship between the radiation image storage plate and the reading arm 61 is not displaced by the swing of the turntable 21, and the image storage processing and the reading processing can be executed in parallel to improve the processing efficiency. It is possible.

In the above-described embodiment, the turntable 21 has a slightly elongated shape, and two radiographic image storage plates are provided on the turntable 21. It is not necessary to limit the number of equipped image storage plates to the one embodiment.

For example, as shown in FIG. 5, the rotary table 21 is formed in a cross shape, and four radiation image storage plates 13, 14, 15, and 1 are arranged concentrically with respect to the rotation center of the rotary table 21.
It is also conceivable to adopt a configuration in which the number of radiation image storage plates is six, or a configuration in which the turntable 21 is formed in a disk shape and three or more radiation image storage plates are provided.

When the number of radiation image storage plates to be mounted is increased by changing the shape of the turntable 21 as described above, the position reproducibility described in one embodiment is high, and Weissenberg measurement can be performed. Can be obtained in the same manner, and further, the number of times that the image storage process can be performed continuously increases as the number of radiation image storage plates increases,
This makes it possible to cope with more various kinds of diffraction measurements.

In the above-described embodiment, in order to control the rotation of the reading arm 61 with reference to the turntable 21, the arm driving means 62 for driving the reading arm 61 to rotate is provided by:
The worm 62a and the motor 62c serving as a driving source are
It is decided to equip the worm wheel 24 integrated with the worm wheel 1. However, the mounting location of the worm 62a and the motor 62c is not limited to the worm wheel 24 as long as it is on the turntable 21 side.

[0048]

As is apparent from the above description, in the X-ray diffraction apparatus according to the first aspect, the moving mechanism for moving the radiation image storage plate to the image reading position and the image storage position is the same circle as the turntable. A plurality of radiation image storage plates are provided on the circumference, and the operation of moving the radiation image storage plate to the image reading position and the image storage position is realized only by controlling the rotation amount of the turntable. Therefore, the adoption of a simple rotary motion mechanism simplifies the moving mechanism, facilitates accuracy in moving to the image reading position and the image storing position, and reproduces the position during the moving operation. Can be improved.

Further, in the X-ray diffractometer according to the first aspect, while the radiation image storage plate at the image reading position is rotated by the storage plate rotating motor, the tip of the reading arm has a radius on the radiation image storage plate. By rotating the reading arm relative to the turntable so as to cross in the direction, it is possible to read and scan the entire area of the radiation image storage plate. Since only a simple rotational movement is required for the movement operation, the simplification of the drive mechanism can be spread to the entire apparatus in combination with the above-described movement mechanism, and excellent in both image storage processing and image reading processing. Position repeatability can be ensured.

Further, it is possible to arrange three or more radiation image storage plates on the rotary table, so that a large number of X-ray diffraction images can be stored continuously.

Further, by causing the rotary table to reciprocate in a minute angle range, a swinging motion can be given to the radiation image storage plate located at the image storage position. Therefore, in synchronization with the rotation of the sample by the X-ray goniometer, by giving a swinging motion to the radiation image storage plate, it becomes possible to perform Weissenberg measurement that measures diffraction lines in association with the orientation of the sample, When combined with the convenience of increasing the number of radiation image storage plates to three or more, the radiation image storage plate can be used for various diffraction measurements.

Further, the X-ray diffractometer according to claim 2 is
A rotation transmission mechanism using a combination of a worm and a worm wheel is used as a driving means of the turntable or the reading arm. With such a mechanism, high movement accuracy can be achieved with a simple configuration having a small number of parts. Therefore, it is possible to relatively easily obtain the above-described improvement in the reproducibility of the position.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a conventional X-ray diffraction apparatus.

FIG. 3 is a plan view of a conventional X-ray diffraction apparatus.

FIG. 4 is an arrow view along the line AA in FIG. 1;

FIG. 5 is a front view of another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sample 2 X-ray goniometer 11, 12, 13, 14, 15, 16 Radiation image storage plate 11a, 12a Radiation image storage surface 20 Moving mechanism 21 Turntable 22 Supporting structure 23 Turntable axis 24, 62b Worm wheel 25, 62a Worms 26, 62c Motors 27, 28 Storage plate rotation motor 60 Radiation image reader 61 Reading arm 62 Arm driving means 63 Excitation light

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 23/00-23/227 G03B 42/02 H04N 1/04

Claims (2)

(57) [Claims] An X-ray goniometer that rotatably holds a sample so as to change an X-ray irradiation direction on the sample;
A plurality of radiation image storage plates for storing an X-ray diffraction image generated from the sample when the sample is irradiated with X-rays;
A moving mechanism for moving the plurality of radiation image storage plates to the image reading position or the image storage position; and a radiation image reading device for reading a radiation image from the radiation image storage plate positioned at the image reading position by the moving mechanism. An X-ray diffraction apparatus comprising: a moving mechanism, wherein the moving mechanism holds the plurality of radiation image storage plates at a position on the turntable on the same circumference with respect to a rotation center of the turntable. By controlling the amount of rotation of the turntable, an arbitrary radiation image storage plate is moved to an image storage position or an image reading position. The radiation image reading apparatus includes: a reading arm; an arm driving unit; A plate rotating motor, wherein the reading arm is rotatably supported at the center of rotation of the rotary table and protrudes radially from the rotary support from the rotary support. An arm portion, and the distal end portion of the arm portion is provided with optical means for irradiating the radiation image storage plate with excitation light and receiving emission light generated on the radiation image storage plate by irradiation of the excitation light. The arm driving means is configured to rotate the shaft support relative to the turntable by power supply from a drive source attached to the turntable, and the storage plate rotating motor performs reading scanning An X-ray diffraction apparatus characterized in that a radiation image storage plate located at an image reading position is rotated at a holding position on the turntable for the purpose. 2. The moving mechanism controls the amount of rotation of the turntable by a worm meshed with a worm wheel fixed to the turntable, and the arm driving means is mounted on a worm wheel fixed to the turntable. The X-ray diffraction apparatus according to claim 1, wherein the worm wheel fixed to the shaft support is driven to rotate using the worm as a drive source.