JP2007114220A - X-ray diffraction measurement method and x-ray diffraction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that X-ray diffraction patterns of respective samples can not be separately and precisely obtained when X-ray diffraction is measured with respect to a plurality of samples. <P>SOLUTION: This X-ray diffraction device includes an X-ray irradiation part for irradiating the sample with an X-ray, a diffracted X-ray detection part for detecting a diffracted X-ray, and a sample holding part for holding the sample, and consists of a position adjustment mechanism including a light application part for applying light to a predetermined position of the sample holding part, a light receiving part for receiving reflected light obtained by applying the light generated from the light application part to the sample, a position control part for measuring a light receiving angle and light receiving position of the reflected light and determining a moving distance in a thickness direction of the sample of the sample holding part in response to them, and a moving part for moving the sample holding part in the thickness direction of the sample in response to the determined moving distance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an X-ray diffraction measurement method and apparatus. Specifically, the present invention relates to an X-ray diffraction measurement method and apparatus suitable for continuously measuring X-ray diffraction of a plurality of samples.

In recent years, advances in fine ceramic technology have made it possible to control the crystal structure, composition, and crystal grain size of inorganic compounds on the micron to nanoscale. For this reason, the development of application of inorganic compounds to electronic materials is rapidly expanding.
Among these, inorganic oxides have a wide range of physical properties such as dielectric properties, magnetic properties, and electrical conductivity. The diversity of functions of inorganic compounds means that the parameters to be controlled as inorganic compounds are extremely diverse, including their non-stoichiometry and crystal structure anisotropy.

  As a result, the conventional method of creating substances one by one and examining their properties not only takes an enormous amount of time to reach the target substance, but also accidental discoveries that are beyond the intuition and experience. It is very unlikely to lead to The key point in searching for new inorganic compounds is how to systematically control various combinations of various raw materials.

  Therefore, what has been proposed is combinatorial chemistry that systematically screens highly probable areas, and is a method for dramatically increasing the synthesis efficiency of substances. For example, in the case of synthesis of an inorganic compound, a solution or slurry containing a raw material having a constituent element is dropped onto a predetermined position on a substrate, and a method of firing this is used to appropriately change the type and amount of the raw material, A large number of inorganic compounds can be synthesized on one substrate.

  On the other hand, as a result of such high-speed synthesis being possible, there has also been a demand for performing material identification work on synthesized samples at a higher speed than before. As a result, multiple samples are arranged at the X-ray irradiation position, and the X-ray diffractometer that irradiates X-rays while shifting the surface on which the samples are arranged horizontally, or only the distance in the thickness direction of the first sample is roughly measured with a light-emitting diode. An X-ray diffractometer that measures X-ray diffraction while horizontally shifting a plurality of samples arranged on the surface after adjustment is also proposed.

  However, in the method using the conventional X-ray diffraction measurement apparatus described above, a pattern in which the detected amount of X-ray diffraction is extremely small or an X-ray diffraction pattern from a sample different from the target sample is seen, etc. It has been found that this problem occurs. That is, the conventional continuous X-ray diffractometer has a problem that it is difficult to accurately obtain X-ray diffraction patterns of the respective samples independently.

  As a result of intensive studies to solve the above problems, the present inventors have found that the main cause is that X-rays do not hit each target sample accurately. When the angle between incident X-rays or diffracted X-rays and the crystal lattice plane in the sample is θ, and 2θ is 5 to 30 degrees, X-rays are incident at an angle close to parallel to the sample surface, and therefore usually exist. Due to the subtle differences in the height of each powder sample surface, the incident X-rays are particularly difficult to hit the target sample. A subtle difference in the height of each sample surface is unavoidable in powder samples, and is also caused by insufficient flatness of the substrate on which the sample is placed.

  Based on the analysis of the above main causes, the present inventors measure and control the distances in the thickness direction of a plurality of sample surfaces one by one, and repeat the X-ray diffraction measurement continuously. And the distance can be measured easily and accurately from the angle or position of the reflected light emitted from the position facing the sample surface toward the sample to be measured. The present invention has been completed.

That is, the gist of the present invention resides in the following (1) to (9).
(1) An X-ray diffraction measurement method for continuously measuring X-ray diffraction images of a plurality of solid samples, wherein the position in the thickness direction of the sample measured in advance before starting measurement of the X-ray diffraction images of each sample And adjusting the position in the thickness direction of the sample based on the above.
(2) The method according to (1), wherein the measurement of the position in the thickness direction of the sample is performed by irradiating the sample with electromagnetic waves and detecting the light receiving angle or light receiving position of the reflected light.

(3) The method according to (2) above, wherein the electromagnetic wave is laser light.
(4) The method according to (2) or (3) above, wherein the reflected light is received by the CCD element.
(5) The method according to any one of (1) to (4) above, wherein the solid sample is an inorganic compound.
(6) In an X-ray diffraction apparatus having an X-ray irradiation unit for irradiating a sample with X-rays, a diffraction X-ray detection unit for detecting diffraction X-rays, and a sample holding unit for holding a sample ,
Measures the light irradiating unit that irradiates light at a predetermined position of the sample holding unit, the light receiving unit that receives the reflected light obtained by irradiating the sample with light generated from the light irradiating unit, and the light receiving angle or position of the reflected light And a position control unit that determines a moving distance of the sample holding unit in the thickness direction of the sample according to the movement, and a moving unit that moves the sample holding unit in the thickness direction of the sample according to the determined moving distance. An X-ray diffractometer having a position adjusting mechanism.

(7) The X-ray diffraction apparatus according to (6), wherein the moving unit has a function of moving the sample holding unit in a three-dimensional direction.
(8) The X-ray diffraction apparatus according to (6) or (7), wherein the light irradiation unit includes a laser diode.
(9) The X-ray diffractometer according to any one of (6) to (8), wherein the light receiving unit includes a CCD element.

According to the X-ray diffraction measurement method of the present invention, when performing X-ray diffraction measurement of a plurality of samples continuously, the position in the thickness direction is measured before the measurement of each sample, and the position adjustment is performed based thereon. Even with a large number of samples, X-ray diffraction measurement can be performed easily and accurately.
In addition, when the sample is an inorganic compound, the necessity for X-ray diffraction measurement is particularly high, and the merit of employing the above method is particularly great.

Furthermore, if the position measurement in the thickness direction of the sample is performed by changing the light receiving angle or the light receiving position of the reflected light of the light irradiated on the sample, the position measurement can be performed easily and accurately.
In this case, if laser light is used as irradiation light, light irradiation in a narrow area becomes possible, and if the reflected light is received by the CCD element, the detection of the reflected light is not performed as the center of gravity value of the light quantity, but the peak of the light quantity. Since it can be performed as a value, the position can be measured more accurately.

Further, according to the apparatus of the present invention, the sample height is determined from the light irradiation unit that irradiates a predetermined position of the sample holding unit, the light receiving unit that receives the reflected light, and the light receiving angle or position of the reflected light determined from them. A position control unit for determining the distance of movement of the sample holder in the thickness direction of the sample, and a moving unit for moving the sample holder in the thickness direction of the sample according to the determined movement distance Therefore, it is possible to continuously measure a plurality of samples, and the measurement is simple and accurate.

Further, if a function for moving the sample holder in the three-dimensional direction is added, continuous measurement of a plurality of samples can be performed more easily.
Furthermore, if a laser diode is used as the light irradiating part, light with good convergence can be easily obtained, so that light irradiation to a narrow sample region is easy.
Furthermore, if a CCD element is used as the light receiving portion, the reflected light can be detected not as the center of gravity value of the light amount but as the peak value of the light amount, so that the position can be measured more accurately.

Hereinafter, embodiments of the present invention will be described in detail.
1 is a side view schematically showing the state of sample measurement, FIG. 2 is a perspective view showing an outline of a measurement sample, and FIG. 3 is a side view showing an outline of an X-ray diffractometer. 4 is a side view schematically showing the principle of measuring the position in the thickness direction of the sample. In the drawings, the x-axis, y-axis, and z-axis indicate the same direction, and the same reference numerals indicate the same.

  As shown in FIG. 2, the sample 10 to be measured is an inorganic oxide, and consists of a plurality of materials having different compositions. Inorganic oxides are produced by dropping a solution containing a raw material containing a constituent element onto a substrate and firing it, and a plurality of inorganic oxides are obtained by changing the type and quantity ratio of the raw materials. A large number of samples (6 × 6 = 36 in FIG. 1) are provided on a substrate 101 such as a platinum substrate or an alumina substrate extending in the xy plane. Although the samples are provided on substantially the same xy plane, the thickness direction of the sample to be irradiated with X-rays (z) is different because the thickness of the sample 10 is slightly different or the substrate is warped. The direction is slightly different for each sample.

  As shown in FIG. 3, the X-ray diffractometer 20 holds an X-ray irradiator 21 for irradiating X-rays toward a sample, a diffracted X-ray detector 22 for detecting diffracted X-rays, and a sample. A sample holder (sample holder) 23 and a sample position adjusting mechanism 24 are provided. The X-ray irradiator 21 and the diffracted X-ray detector 22 have a goniometer structure that rotates relative to the object around the center of rotation so as to satisfy the Bragg equation.

The X-ray irradiation unit 21 includes an X-ray tube 211 that generates X-rays, a single crystal monochromator 212 for monochromaticizing the generated X-rays, and a collimator 213 that collimates incident X-rays.
The diffracted X-ray detector 22 includes a counter tube 221 that detects diffracted X-rays and an output controller 222 that outputs an X-ray diffraction spectrum based on the detection result.

  The position adjusting mechanism 24 includes a laser diode (light irradiation unit) 241 that irradiates light to a predetermined position of the sample holding unit 23, and a slit 245 that transmits reflected light obtained by irradiating the sample with light generated from the laser diode 241. The CCD element (light receiving unit) 242 that receives the reflected light that has passed through the slit 245 and the light receiving angle of the reflected light are measured, and the movement distance in the sample thickness direction (z axis) of the sample holding unit is accordingly measured. A position control unit 243 to be determined and an xyz stage (moving unit) 244 that enables the sample holder 23 to move in the z-axis direction and also to move in the xy direction according to the determined moving distance.

The X-ray diffraction measurement of the sample is automatically and continuously performed by the output control unit 222 and the position control unit 243, and the specific operation is as follows.
First, the first sample 10 on the sample holder 23 connected to the xyz stage 244 is determined in advance as the rotation center of the goniometer by the xyz stage 244 of the X-ray diffraction apparatus 20 based on an instruction from the position control unit 243 at the start of measurement. It is moved in the xy direction so that the obtained xy coordinate position is obtained. Subsequently, the first sample 10 is irradiated with laser light 30 having a wavelength of 690 nm from the laser diode 241 of the position adjusting mechanism 24, and a part of the diffusely reflected light is received by the slit 245, and the reflected light 31 that has passed through the slit 245 is reflected. Light is received by the CCD element 242.

The laser diode 241, the slit 245, and the CCD element 242 that are light transmission sources are all fixed. The light source is the origin, the light irradiation position on the sample 10 is point B, the light receiving position on the CCD element 242 is point A, and the slit position is point C (FIG. 4). The laser beam 30 is applied to the sample in parallel with the thickness direction z of the sample. When the height of the sample is different and the point B changes, the angle α between the reflected light 31 that can pass through the slit 245 of the diffuse reflected light and the sample thickness direction changes, but the light receiving position A also changes. The angle α is obtained by detecting the point A. The distance L in the sample surface direction and the distance D in the sample thickness direction between the origin of the light source and the slit C point are known because they are fixed. Therefore, the distance H in the sample thickness direction of the sample surface from the origin to be obtained is expressed as the following equation (1) using the known values L and D and the measured value α.

[Equation 1]
H = (L + Dtanα) / tanα (1)
In this way, the deviation of the distance in the thickness direction of the sample surface can be accurately determined. Therefore, the position control unit 243 calculates and calculates the distance H in the sample thickness direction of the sample surface from the desired origin based on the above equation (1) from the position of the light receiving position (point A). The position control unit 243 further calculates the movement distance in the z direction of the sample holder 23 from the distance H, which is an index of the current position in the Z direction, and the position in the z direction that is predetermined as the rotation center of the goniometer, It is moved in the z direction by the xyz stage.

  After the position of the first sample 10 is accurately set by the above operation, X-ray diffraction measurement is performed by a normal method. That is, X-rays are generated by the X-ray tube 211, and then monochromatic by the single crystal monochromator 212, and then collimated by a collimator 213 or a slit, and irradiated to the first sample 10. Diffracted X-rays from the sample are counted by the counter tube 221. X-ray irradiation and diffracted X-ray counting are sequentially performed while changing the diffraction angle with a goniometer under the control of the output control unit 222. As a result, the X-ray diffraction intensity corresponding to the diffraction angle 2θ is X-ray. Obtained as a diffraction spectrum.

Subsequently, the same operation is performed on the second sample 10 adjacent to the first sample. That is, first, after a predetermined movement in the xy direction, position measurement and position adjustment in the z-axis direction are performed, and then normal X-ray diffraction measurement is performed.
The above operation is further performed on the third and subsequent samples, and X-ray diffraction measurement is performed on all the samples. Prior to the X-ray diffraction measurement of each sample, the position adjustment in the thickness direction of the sample is performed in advance, so that the incident X-ray hits the sample reliably, and as a result, an accurate X-ray diffraction spectrum is obtained for each sample. be able to.

The above description is merely an example, and various modifications can be made without departing from the gist of the present invention.
For example, by interposing an optical lens between the slit 245 and the CCD element 242, the beam intensity distribution in the cross section of the reflected light 31 can be made uniform, the beam diameter can be reduced, and a more accurate sample position in the z direction can be obtained. Measurement can be performed.

  In the above example, an X-ray tube is used as the X-ray source, but a rotating counter-cathode X-ray generator or synchrotron radiation can also be used. In the above example, a single crystal monochromator is used for monochromatic X-rays, but a wave height analyzer, a β-filter, a balanced filter, or the like can also be used. You may use the mirror which served as monochromatic and parallelization. In addition, the above example is an example in which incident X-rays are collimated, and this method is preferable because the unevenness of the sample hardly affects the X-ray diffraction angle. A method of irradiating the sample with X-rays is also possible.

  Further, as the X-ray detector, an X-ray film, a two-dimensional detector, and an imaging plate can be used in addition to the counter tube raised in the above example. Furthermore, as the X-ray diffraction apparatus, either a vertical type or a horizontal type can be used, but a vertical type in which the sample surface is held horizontally is preferable from the viewpoint of preventing the measurement sample from falling. In addition to the reflective type, a transmissive type can also be used.

In addition, the goniometer in the above example is a type that drives the X-ray detector at various angles with respect to the sample surface, but the X-ray simultaneous detection type detection that is circumferentially arranged in the measurement angle region. The 2θ-X-ray diffraction intensity may be measured by using an instrument.
Furthermore, in the above example, light having a wavelength of 690 nm is used as the light from the light irradiation unit for position measurement. Generally, for example, various wavelengths ranging from ultraviolet to infrared having a wavelength of about 150 to 3000 nm are used. Although it can be used, its wavelength is not particularly limited, and various electromagnetic waves can be used.

Furthermore, the method for determining the sample height by receiving the reflected light is not limited to the method according to the above formula (1). For example, when the level of the sample surface is relatively high, the reflected light is generally uniform, so that the sample height can be obtained directly by measuring the light receiving position on the CCD panel without providing the slit 245.
Furthermore, in the above example, the position in the thickness direction of the sample is obtained by detecting the light receiving position of the reflected light from the sample by the CCD element. However, the position can also be determined by the light receiving angle of the reflected light. is there. For example, a mirror with variable angle is installed at the destination of the reflected light from the sample, the angle of the mirror is scanned, and the light reflected from the sample is further reflected by the CCD element or photodetector. By determining the mirror angle when it hits the fixed point, it is possible to accurately determine from which angle the reflected light from the sample before hitting the mirror flew. However, in this method, there are many movable parts such as variable angle mirrors, which not only requires more time for operation, but also requires extra maintenance, so a method for detecting the light receiving position of the reflected light from the sample Is preferred.

  Furthermore, in the above example, in performing X-ray diffraction measurement of a plurality of samples, (1) position control of the first sample, (2) X-ray diffraction measurement of the first sample, (3) second (4) X-ray diffraction measurement of the second sample, and a method of alternately repeating position control and X-ray measurement. For example, for all samples, first, in the thickness direction After the position measurement is performed and the position or the movement distance is stored in the storage device, the stored data can be called to perform only the position movement before the X-ray measurement of each sample.

Furthermore, in the above example, an example is shown in which an output control unit that controls the X-ray measurement itself and a position control unit that performs position control are separately provided, but control is performed by a single control unit that has these functions. It is possible and rather preferable.
Furthermore, the sample used for the measurement is preferably an inorganic compound from the viewpoint of the necessity / importance of X-ray diffraction measurement, but is not limited to this, and various kinds of organic compounds, polymers, and the like can be used. It can be illustrated.

Perspective view schematically showing the state of the measurement sample Side view showing the outline of X-ray diffraction measurement Explanatory drawing showing the outline of the X-ray diffraction apparatus It is a block diagram which shows the measuring method of X-ray diffraction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sample 20 X-ray diffractometer 21 X-ray irradiation part 22 Diffraction X-ray detection part 23 Sample holder 24 Position adjustment mechanism 211 X-ray tube 212 Single crystal monochromator 213 Collimator 221 Counter tube 222 Output control part 241 Laser diode 242 CCD Element 243 Position control unit 244 xyz stage 245 Slit

Claims (9)

  An X-ray diffraction measurement method for continuously measuring X-ray diffraction images of a plurality of solid samples, based on a pre-measured position in the thickness direction of the sample before starting measurement of the X-ray diffraction images of each sample. A method comprising adjusting a position in a thickness direction of a sample.   The method according to claim 1, wherein the measurement of the position in the thickness direction of the sample is performed by irradiating the sample with electromagnetic waves and detecting a light receiving angle or a light receiving position of the reflected light.   The method according to claim 2, wherein the electromagnetic wave is a laser beam.   The method according to claim 2 or 3, wherein the reflected light is received by a CCD element.   The method according to any one of claims 1 to 4, wherein the solid sample is an inorganic compound. In an X-ray diffraction apparatus having an X-ray irradiation unit for irradiating a sample with X-rays, a diffraction X-ray detection unit for detecting diffraction X-rays, and a sample holding unit for holding a sample,
Measures the light irradiating unit that irradiates light at a predetermined position of the sample holding unit, the light receiving unit that receives the reflected light obtained by irradiating the sample with light generated from the light irradiating unit, and the light receiving angle or position of the reflected light And a position control unit that determines a moving distance of the sample holding unit in the thickness direction of the sample according to the movement, and a moving unit that moves the sample holding unit in the thickness direction of the sample according to the determined moving distance. An X-ray diffractometer having a position adjusting mechanism.   The X-ray diffraction apparatus according to claim 6, wherein the moving unit has a function of moving the sample holding unit in a three-dimensional direction.   The X-ray diffraction apparatus according to claim 6, wherein the light irradiation unit includes a laser diode.   The X-ray diffraction apparatus according to claim 6, wherein the light receiving unit includes a CCD element.

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