JP2001311705A - X-ray diffraction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate setting a large sample horizontally when a vertical goniometer is used. SOLUTION: Three adjusting members 8 comprising screws 9, springs 10 and motors 11 are arranged on a sample support plate 12, and a sample 6 is engaged with the adjusting members 8. Three distance sensors 7 for measuring the distance up to the sample surface are disposed over the sample 6. The sample surface is adjusted horizontally by driving the adjusting members so that the outputs of the distance sensors become the same prescribed value, and height adjustment is executed so that the rotation center of the goniometer agrees with the sample surface. After setting the sample, a diffracted X-ray obtained by diffracting an X-ray from an X-ray tube 1 by the sample 6 is detected to execute X-ray diffraction analysis, by moving synchronously and rotatavely the X-ray tube 1 and a detector 3 around the rotation center 5.

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 having a vertical goniometer in which a sample is placed horizontally and a diffraction X-ray detector or the like is driven in a vertical plane.

[0002]

2. Description of the Related Art An X-ray tube for irradiating a sample with X-rays and a detector for detecting diffracted X-rays radiated from the sample are placed synchronously on a sample to be analyzed. An X-ray diffractometer equipped with a vertical goniometer driven to rotate around a sample in a vertical plane is known. In particular, for the purpose of analyzing a large sample, a vertical goniometer is employed because the degree of freedom in designing the structure around the sample is high and the structure can be easily optimized.

In a vertical goniometer, the sample needs to be placed horizontally on the surface to be irradiated with X-rays. In particular, in the case of a large sample, the accuracy must be increased. Conventionally, in order to level the sample surface, the operator individually adjusts the tilt using a level, etc., and further adjusts the sample height so that the height position of the sample surface matches the center of the goniometer. I was

[0004]

In the conventional method, since the tilt and height of the sample surface are adjusted for each sample by an operator's operation, it takes a lot of time to set the sample.

[0005] The present invention has been made in view of the above circumstances, and a simple X and Y adjustment of the sample tilt and height adjustment.
It is an object to provide a line diffraction device.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an X-ray tube for irradiating a sample placed so that the surface to be analyzed is horizontal with X-rays, and an X-ray tube emitted from the sample. An X-ray diffractometer having a goniometer that vertically drives a detector that detects diffracted X-rays, and at least three distance sensors for measuring a vertical distance from the sample surface, and a sample surface height. At least three height adjusting members to be adjusted, and the height adjusting members are driven based on a signal from the distance sensor so that the sample surface is horizontal and coincides with the rotation center height of the goniometer. And a control device that performs the control.

The X-ray diffractometer of the present invention includes a goniometer that holds a sample horizontally and has a rotation axis in a horizontal plane at a height corresponding to the surface of the sample.
The present invention is applied to an X-ray diffractometer having a vertical goniometer in which a ray tube and an X-ray detector are rotationally driven symmetrically in synchronization about the rotation axis.

A plurality (at least three) of distance sensors are arranged above the sample, and the distance sensors measure the distance along the vertical direction to the sample surface. Assuming that a plurality of distance sensors arranged in advance are mutually calibrated, if the distances to the sample surface measured by the distance sensors are the same, the sample surface can be regarded as horizontal.

On the other hand, since the sample is supported by at least three height adjusting members, by individually adjusting the height adjusting members, the tilt (inclination) of the sample surface can be adjusted and each height can be adjusted. By adjusting the adjusting member by the same amount, the absolute height of the sample is adjusted, that is,
Positioning with respect to the rotation center of the goniometer can be performed. Since the height adjusting member is controlled by the control device by driving a motor or the like, the tilt and height of the sample surface are automatically adjusted based on the data from the distance sensor described above.

[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 schematic view of a main part of the X-ray diffraction apparatus of the present invention as viewed from the side, and FIG. 2 is a view as viewed from above.

The sample 6 to be analyzed is placed horizontally, and the surface of the sample is irradiated with primary X-rays 14 generated at one point (or linear shape) in the X-ray tube 1. The primary X-ray 14 is restricted to an appropriate divergence angle by the divergence slit 2 arranged in front of the X-ray irradiation window of the X-ray tube, and hits the surface of the sample 6. The diffracted X-ray 15 diffracted by the sample surface is received by the light receiving slit 4 arranged in front of the detector 3.
The intensity of the diffracted X-rays detected by the detector 3 through the detector 3 is measured. The X-ray tube 1 and the detector 3 are configured to be rotationally and symmetrically rotated around a rotation center 5 by a goniometer (not shown). This rotation center 5
The height position of the sample is adjusted so that the sample and the sample surface match.

In this state, the X-ray tube 1 is driven to rotate around the rotation center 5 in a plane perpendicular to the horizontal plane as indicated by an arrow A, and the detector 3 is rotated about the rotation center 5 in the same plane. Arrow B
It is rotationally driven as shown in FIG. At this time, an angle θ1 formed between a line connecting the X-ray generation point and the rotation center 5 and the sample surface, and an angle θ formed between a line connecting the light receiving slit 4 and the rotation center 5 and the sample surface
By being driven so that 2 is always equal, the X-rays that are spread and irradiated on the sample surface and diffracted at each position on the sample surface are concentrated at the position of the light receiving slit. Such a basic layout is called a vertical goniometer.

The sample 6 is engaged with three adjusting members 8 provided on the sample support plate 12, and by driving these adjusting members, the tilt and height of the sample are adjusted. The adjusting member 8 includes a screw 9 which advances and retreats with respect to the sample support plate 12 with rotation, a spring 10 which is fitted around the plate 9 to take a backlash, etc., and a motor 11 which rotates the screw 9.
Consists of The adjusting members are 13a to 13c in FIG.
Three (8a, 8b, 8c) are arranged at appropriate intervals below the position indicated by.

Since the pitch of the screw 9 of the adjusting member is known, the relationship between the amount of rotational drive by the motor 11 and the amount of advance and retreat of the screw 9 is known in advance, and the height of the position where each adjusting member 8 pushes the back surface of the sample is controlled. can do. The tilt of the sample surface can be adjusted by individually adjusting the amount of advance and retreat of each screw 9. If the amount of advance and retreat of each screw 9 is changed by the same amount, the sample surface is translated in the vertical direction. be able to.

On the other hand, a plurality of distance sensors 7 are disposed above the sample 6, and each distance sensor 7 looks at a different point on the sample surface, and a vertical line from the distance sensor to the sample surface is provided. The distance in the direction (perpendicular to the horizontal plane) can be measured. In the example of FIGS. 1 and 2, each of the three distance sensors 7a, 7b, 7c has a measurement point 13 on the sample surface.
A, 13b, and 13c are observed, and the vertical distance to that point is measured. The adjusting members 8a, 8b and 8c described above are provided below these measuring points, and the distance measurement and the height adjustment amount correspond directly, so that the amount to be controlled is easy to understand and simple. Of course, even if the position where the distance sensor 7 is viewed and the position where the adjustment member is provided are different, the height of the adjustment member 8 is calculated by mathematically calculating the position of the sample surface based on the data of the distance sensor 7. The adjustment amount can be calculated.

The tilt adjustment of the sample surface is performed as follows. Three
The mounting positions of the two distance sensors 7a, 7b, 7c are calibrated in advance. That is, the adjustment sample is set in advance using a level or the like so that the adjustment sample is placed horizontally and its surface coincides with the rotation center of the goniometer. In this state, the three distance sensors 7a, 7b,
The predetermined value is displayed by finely adjusting the mounting height position of the distance sensor or changing the offset value or the like provided inside the control device so that all the reference values 7c indicate the same predetermined value. . The predetermined value is set to, for example, zero, and a distance sensor is displayed so that a positive value is displayed when the sample surface is above the predetermined position, and a negative value is displayed when the sample surface is below the predetermined position. Set the output circuit (or program).

After setting as described above, when setting an actual measurement sample, three distance sensors 7a,
The three adjusting members 8a, 8b, 3b, 7b, 7c are set such that the output values of the three adjusting members 8a, 8b,
8c. When the outputs of the three distance sensors all indicate the same predetermined value, the tilt adjustment of the sample surface is completed, and the sample surface is horizontally arranged. At this time, the height position of the sample surface also coincides exactly with the rotation center 5 of the goniometer.

In the above-described adjustment procedure, the adjustment of the sample height and the adjustment of the sample height are finished at the same time. However, the sample height can be adjusted more accurately by the following procedure.

In the same manner as described above, after the tilt adjustment is completed so that the outputs of the three distance sensors become the predetermined values, the three adjusting members 8a, 8b and 8c are driven by the same distance to move the sample surface. Lower down enough. In this state, the sample surface is lower than the rotation center of the goniometer, and there is no object near the rotation center of the goniometer. After that, the goniometer is driven until the diffraction angle becomes zero, and the X-ray tube 1 and the detector 3 are driven.
Are horizontally opposed. This state is shown in FIG.

At this time, the X-rays 14 generated from the X-ray tube 1 are directly incident on the detector 3 and detected. When the adjustment members 8a, 8b, and 8c are simultaneously driven by the same amount to move the sample upward in this state, the X-ray intensity detected by the detector 3 decreases because the sample 6 gradually blocks the X-ray. It gradually goes down. Then, when the intensity of the X-rays monitored by the detector 3 becomes a half of the initial value, the lifting of the sample is stopped and the setting position is set. This means that the sample surface coincides with the center position of the X-ray beam 14, that is, the rotation center of the goniometer.

In the above procedure, it is assumed that the center of the primary X-rays 14 generated from the X-ray tube 1 is set in advance so as to correctly face the center of the goniometer. Needless to say, it is necessary to select the divergent slit 2 and the light receiving slit 4 and the X-ray intensity emitted from the X-ray tube 1 appropriately.

[0022]

According to the X-ray diffraction apparatus of the present invention, a distance sensor for directly measuring the height position of the sample surface is provided, and the height adjusting member for the sample surface is automatically driven based on the data. It is easy to adjust the tilt and height of the sample surface of a large sample, and the setting time is shortened. Further, even if the sample surface to be analyzed and the bottom surface of the sample holder are not parallel, setting can be performed so that the sample surface is horizontal.

[Brief description of the drawings]

FIG. 1 is a schematic view of an X-ray diffraction apparatus according to the present invention.

FIG. 2 is a diagram of a sample unit viewed from above.

FIG. 3 is a diagram illustrating height adjustment of a sample surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... X-ray tube 2 ... Divergent slit 3 ... Detector 4 ... Light receiving slit 5 ... Rotation center 6 ... Sample 7 ... Distance sensor 8 ... Adjustment member 9 ... Screw 10 ... Spring 11 ... Motor 12 ... Sample support plate 13 ... Measurement point 14: primary X-ray 15: diffraction X-ray

Claims (1)

[Claims] 1. An X-ray tube for irradiating an X-ray to a sample placed so that a surface to be analyzed is horizontal and a detector for detecting a diffracted X-ray radiated from the sample are vertically driven to rotate. In an X-ray diffractometer having a goniometer, at least three distance sensors for measuring a vertical distance from the sample surface, at least three height adjusting members for adjusting a sample surface height, and the distance sensor An X-ray diffractometer, comprising: a controller that drives the height adjusting member based on the signal of (1) to control the sample surface so as to be horizontal and coincide with the rotation center height of the goniometer.