JP4604242B2 - X-ray diffraction analyzer and X-ray diffraction analysis method - Google Patents

Description

  The invention of this application irradiates a sample with an X-ray diffraction pattern including local structure information of a sample having an inhomogeneous crystal structure that is fixedly held, such as a polycrystalline body, a member having a strain or a defect, and the like. X-ray diffraction analysis apparatus for obtaining using an X-ray tube that generates characteristic X-rays of a predetermined element as X-rays and a two-dimensional position sensitive detector composed of a plurality of detection elements arranged two-dimensionally And an X-ray diffraction analysis method.

  The X-ray diffraction method is a technique for obtaining an X-ray diffraction pattern corresponding to the crystal structure of a sample by detecting diffraction X-rays generated when the crystalline sample is irradiated with X-rays. It is known that X-ray diffraction patterns are acquired in various formats depending on the purpose and the apparatus used. For example, in a normal powder X-ray diffractometer, it is acquired in the form of a set of diffraction angle and diffraction X-ray intensity data, and is represented by a graph with the horizontal axis representing the diffraction angle and the vertical axis representing the diffraction X-ray intensity. The In a Debye-Scherrer camera or the like, an X-ray diffraction pattern is acquired as a photograph in which the intensity of diffracted X-rays appears as shading.

  In general, the powder X-ray diffraction method using powder (polycrystal) as a target is intended to know the crystal structure of a sample having a uniform and random orientation. Therefore, it is important to collect a plurality of diffraction spots (where the diffraction X-ray intensity is strong, which appears as a peak in the diffraction X-ray intensity profile with respect to the diffraction angle) and to grasp the intensity and the geometrical positional relationship between them. is there. Therefore, typically, characteristic X-rays from an X-ray tube are used as incident X-rays to illuminate the sample, and the diffraction angle-dependent intensity of the intensity of the diffracted X-rays from the sample by so-called θ / 2θ scanning with a two-axis goniometer Measure the profile. In this case, an optical system that approximately satisfies the concentration method is usually used. That is, only the X-rays that have passed through the diverging slit through the parallel slit among the X-rays diverged from the light source on the focal circle are diffracted by the plane sample in contact with the focal circle. Diffracted X-rays concentrate on the light receiving slit on the focal circle, and are detected by the detector through the parallel slit and the scattering slit (Non-Patent Document 1).

  On the other hand, a so-called real sample that is not a sample made for the purpose of X-ray diffraction measurement includes, for example, a texture in which different crystal structures coexist, different orientations are included, is defective, and is loaded. In many cases, the crystal structure is not uniform due to the distortion, and it is important to know the local crystal structure of each part of the sample. However, since the information obtained by the above general powder X-ray diffraction method is the average information of the region illuminated by the incident X-ray of the sample, information on the difference in crystal structure depending on the site in the region is used. I can't get it.

  Therefore, a technique has been proposed in which the X-ray beam size irradiated on the sample is reduced to obtain information on each part of the sample (Non-Patent Document 2). Certainly, incident X-rays with a small beam size are used, the X-ray irradiation area on the sample is changed by XY scanning of the sample stage, and in each irradiation area, as in the conventional powder X-ray diffraction method, θ / If measurement is performed by 2θ scanning, it is possible to obtain information on each part of the sample. However, there is a problem that it takes a long time to measure one sample. For example, the time required to obtain an X-ray diffraction pattern for one point (one X-ray irradiation region) on the sample is about 20 to 30 minutes, which is the same as the measurement time by a general powder X-ray diffraction method. For example, if the number of measurement points on the sample is 10000 points of 100 × 100, the measurement takes about 5000 hours, that is, about 200 days.

In order to shorten the measurement time, recently, by using a one-dimensional or two-dimensional position sensitive detector, each element of the detector detects information of diffracted X-rays having different diffraction angles. A technique in which θ / 2θ scanning is omitted is common. However, in order to obtain information on each part of the sample, it is not necessary to measure one point at a time. Therefore, when trying to obtain information on each part in a wide area of the sample, the measurement point is It becomes a large number and still takes a long time for measurement.

On the other hand, the sample is supported so as to be rotatable about an axis perpendicular to the optical axis of the incident X-ray, and the position sensitive detector is installed with a fixed scattering angle (2θ angle) with respect to the incident X-ray. By placing a collimator between the position-sensitive detector and each part in the measurement area on the sample surface and each detection element of the position-sensitive detector, the entire measurement area is parallel. A technique to obtain diffraction patterns only by θ-scanning of the sample without scanning the measurement point on the sample by detecting the diffracted X-rays from each part with separate detection elements by illuminating with good monochromatic X-rays It has been proposed (Patent Document 1). In this technique, since it is not necessary to scan the X-ray irradiation position on the sample, information on the crystal structure of each part of the sample can be obtained in a time comparable to the measurement time required for a general powder diffraction method. However, since the sample is rotated, incident X-rays having a large size are required to always illuminate a desired region with incident X-rays. In Patent Document 1, it is assumed that an X-ray tube is used as an incident X-ray source. However, since the X-ray tube is not a strong X-ray source such as radiated light, the intensity of detected diffracted X-rays However, there is a problem that the time required to obtain one diffraction pattern becomes long. For example, according to the report of the inventors of the invention according to Patent Document 1, even if the sample can acquire an image with an imaging time of 1 second or less when using radiated light, incident X-rays are emitted as 1 mrad diverging light. When a 1 mm point-focused X-ray tube that generates 1 mm is placed 1 m away from the sample and used, an imaging time of about 15 minutes is required (Non-patent Document 3). In Non-Patent Document 3, as a countermeasure, it is proposed to increase the intensity of incident X-rays by placing a parallel element made of a multilayer film downstream of the X-ray tube. It also points out the problem that the incident X-ray irradiation area becomes narrow.
Makoto Kato, “X-ray diffraction analysis”, Department of Inorganic Materials Engineering, Faculty of Engineering, Tokyo Institute of Technology, Ceramics Course 3, Uchida Otsukuru, 1990, pp.119-120 Y. Chikaura, Y. Yoneda and G. Hildebrandt, "Polycrystal scattering topography", Journal of Applied Crystallography, vol.15, pp.48-54, 1982 German Patent No. 4430615 (DE 4430615 C2) T. Wroblewski, D. Breuer, H.-A. Crostack, F. Fandrich, M. Gross and P. Klimanek, "Mapping in Real and Reciprocal Space", Materials Science Forum, vols. 278-281, pp. 216- 220, 1998

  The invention of this application reduces the intensity attenuation in the optical path until the X-ray beam emitted from the X-ray tube reaches the sample as much as possible, for example, a polycrystalline body, a member having a strain or a defect, etc. X-ray diffraction pattern with local structure information of sample with non-uniform crystal structure, especially two-dimensional distribution image of diffracted X-ray intensity when focusing on specific crystal lattice plane, such as laboratory and residual stress measurement It is an object of the present invention to provide an X-ray diffraction analysis apparatus and an X-ray diffraction analysis method that can be acquired easily and in a short time at a site where a structure requiring nondestructive inspection is installed.

According to the invention of this application, the problem is that an X-ray diffraction pattern including local structure information of a sample having a non-uniform crystal structure that is fixedly held is used as an incident X-ray that illuminates the sample, and the characteristics of a predetermined element. In an X-ray diffraction analysis apparatus for obtaining using an X-ray tube for generating X-rays and a two-dimensional position sensitive detector composed of a plurality of detector elements arranged in two dimensions, the X-ray tube comprises: The incident X-ray is a position that can illuminate the entire measurement region to be observed on the sample surface, and is fixed and held at a position that is as close as possible to the sample as long as it is not in contact with the sample. The sensitive detector can be rotated around a rotation axis extending perpendicularly to the optical axis of the incident X-ray through the center of the measurement area on the sample surface, and is sensitive to the sample in two dimensions. For adjusting the distance to the detector Arranged such distance is 2~5mm between the sample surface and the detector surface at a position where the detector plane of the two-dimensional position sensitive detector is directly opposite to the sample surface by using a In order to distinguish and detect the diffracted X-rays diffracted by the sample and emitted from each part in the measured region by different detection elements of the two-dimensional position sensitive detector, the angle divergence of the diffracted X-rays is detected. An angle divergence limiting means for limiting the angle is provided so as to rotate integrally with the two-dimensional position sensitive detector around the rotation axis, and the intensity of the diffracted X-ray detected by the detection element is set for each pixel value. This is solved by an X-ray diffraction analyzer characterized by having an image forming recording section for forming and recording a two-dimensional diffraction X-ray image.

An X-ray tube that generates a characteristic X-ray of a predetermined element as an incident X-ray that illuminates the sample, and an X-ray diffraction pattern including local structure information of the sample having a non-uniform crystal structure that is fixedly held; In an X-ray diffraction analysis method for obtaining using a two-dimensional position sensitive detector composed of a plurality of detector elements arranged two-dimensionally, the sample is emitted from an X-ray tube arranged close to the sample By illuminating the entire measurement region to be observed on the sample surface with incident X-rays incident on the sample, by limiting the angular divergence of the diffracted X-rays that are diffracted by the sample and emitted from each part in the measurement region, Using a mechanism that distinguishes and detects the diffracted X-rays emitted from each part with different detection elements of the two-dimensional position sensitive detector and adjusts the distance between the sample and the two-dimensional position sensitive detector the sample table Te The distance between the sample surface and the detector surface is 2 to 5 mm at the position where the detector surface of the two-dimensional position sensitive detector is directly facing the two-dimensional position sensitive detector. The two-dimensional position sensitive detector is moved to a desired angular position by rotating the type detector around a rotation axis extending perpendicularly to the optical axis of the incident X-ray through the center of the measurement area on the sample surface. This is solved by an X-ray diffraction analysis method characterized in that a two-dimensional diffraction X-ray image is formed and recorded with each pixel value being the intensity of the diffraction X-ray detected by each detection element at that position. .

  In the X-ray diffraction analyzer and the X-ray diffraction analysis method according to the invention of this application, the sample is fixedly held, that is, the sample is not moved during the measurement, and a predetermined element is used as incident X-rays that illuminate the sample. The X-ray tube for generating the characteristic X-ray is fixed and held at a position where it can illuminate the entire measurement region of the sample and as close as possible to the sample as long as it does not contact the sample. That is, the X-ray beam generated in the immediate vicinity of the sample is incident on the sample without passing through any optical element that monochromatic or parallelizes the X-ray beam, so that the X-ray beam passes through the optical element. In addition, since the distance between the X-ray tube and the sample is short, the intensity loss due to scattering / absorption in the atmosphere can be minimized. In other words, the X-ray intensity loss can be extremely small as compared with the case where the incident X-ray is converted into a parallel monochromatic X-ray as assumed in Patent Document 1. As a result, even in a laboratory or field where a strong X-ray source such as synchrotron radiation cannot be used, a two-dimensional diffracted X-ray image including the local structure information of the sample is acquired in a short time using an X-ray tube. It becomes possible. Further, since the sample and the X-ray tube are not moved during the measurement, the region illuminated by the incident X-ray on the sample does not change.

  In the X-ray diffraction analyzer of the invention of this application, the X-ray tube for generating incident X-rays is an X-ray tube for generating an X-ray beam having a linear thin rectangular cross section, and the long axis of the rectangular cross section is the above-mentioned When the X-ray tube is fixed and held so that the angle extending between the sample surface and the optical axis of the incident X-ray is 0 to 3 degrees, the X-ray tube is used as a sample. Even if they are arranged close to each other, a wide area of the sample can be illuminated uniformly.

  In the X-ray diffraction analyzer of the invention of this application, the X-ray tube can be exchanged, and the X-ray tube can be selected from a plurality of X-ray tubes that generate characteristic X-rays of different elements. And the use of incident X-rays with wavelengths that do not generate fluorescent X-rays depending on the sample, and the target lattice plane when the rotation (swivel) angle range of the two-dimensional position sensitive detector is limited. It is possible to use incident X-rays having such a wavelength that the diffraction angle is an angle convenient for measurement.

The X-ray diffraction analyzer of the invention of this application is provided with a mechanism for adjusting the distance between the X-ray tube and the sample and the angle formed by the sample surface and the optical axis of the incident X-ray. Even in the case of measuring an actual sample whose shape and size are not constant, it is possible to realize optimal illumination of the measurement region by incident X-rays. These adjustments are made before measurement, and when the measurement starts, the sample and the X-ray tube are not moved, so that the mechanism may be manually operated.

  In the X-ray diffraction analyzer of the invention of this application, when the X-ray extraction window of the X-ray tube is made of a filter material that absorbs Kβ rays out of characteristic X-rays generated in the X-ray tube, Kα rays and Kβ rays ( X-rays of wavelengths other than these may be included, but the intensity is weak and can be ignored). Using a mixed X-ray beam as incident X-rays adversely affects the diffracted X-ray image acquired. In some cases, the Kβ ray component can be eliminated. At this time, it is not necessary to increase the distance between the X-ray tube and the sample by using an extraction window made of a filter material instead of inserting another optical element into the incident X-ray optical path.

  In the X-ray diffraction analyzer of the invention of this application, the rotation angle range of the two-dimensional position sensitive detector and the angle divergence limiting means is from a position of 60 degrees to a position of 120 degrees with respect to the sample surface. Since the rotation of the two-dimensional position sensitive detector and the sample is not hindered even if the distance between the two-dimensional position sensitive detector and the sample is not greatly separated, the apparatus can be configured compactly. For most samples, if the diffraction pattern is acquired within this rotation angle range, the purpose of imaging the distribution of crystal structure, imaging of the residual stress distribution, etc. can be sufficiently achieved.

  In the X-ray diffraction analyzer of the invention of this application, when a mechanism for adjusting the distance between the sample surface and the two-dimensional position sensitive detector is provided, the rotation angle of the two-dimensional position sensitive detector is provided. Depending on the position, it is possible to realize the arrangement of the two-dimensional position sensitive detector that is closest to the sample as long as the incident X-rays are not blocked and the member does not contact. However, since this distance is fixed during the rotation angle scanning of the two-dimensional position sensitive detector, the mechanism may be a manually operated mechanism.

  Hereinafter, embodiments of the invention of this application will be described in detail with reference to the drawings.

  FIG. 1 shows a conceptual diagram of an X-ray diffraction analyzer according to the invention of this application.

  The sample (1) is fixedly held by the sample support part (2) and is not moved during the measurement.

  A two-dimensional position sensitive detector (3) comprising a plurality of detector elements arranged two-dimensionally is in the same plane as the measured region (A) to be observed on the sample surface by the detector support (4). Is held so as to be able to turn (turn) around a rotation axis (5) extending through the center of the area (A) to be measured, and the two-dimensional position sensitive detector (3) is detected at every turning position. The vessel surface (a two-dimensional surface formed by the detection surfaces of all the detection elements) always anticipates the region to be measured (A). Between the sample (1) and the two-dimensional position sensitive detector (3), diffracted X-rays (6) generated by the sample (1) and emitted from each part in the measurement area (A) on the sample surface ), The diffracted X-rays (6) emitted from different parts in the measurement region (A) can be distinguished and detected by separate detection elements of the two-dimensional position sensitive detector (3). An angle divergence restricting means (7) such as a collimator (for example, a capillary plate in which synthetic quartz capillaries are assembled, or a light metal subjected to the same processing by a lithography technique) is provided. The angle divergence limiting means (7) is rotated around the rotation axis (5) integrally with the two-dimensional position sensitive detector (3). Therefore, regardless of the rotational position of the two-dimensional position sensitive detector (3), each detection element is diffracted X-rays emitted from a specific specific part (A). Only 6) is detected. The two-dimensional position sensitive detector (3) and the angle divergence limiting means (7) may be integrated.

Although not shown in FIG. 1, the two-dimensional position sensitive detector (3) generates and records a two-dimensional diffraction X-ray image having the diffraction X-ray intensity detected by each detection element as each pixel value. For this purpose, an image forming recording unit is provided inside or outside.

  An X-ray tube (9) that generates a characteristic X-ray of a predetermined element and emits a characteristic X-ray beam having a thin rectangular cross section (linear focal point) as an incident X-ray (8) is provided for the incident X-ray (8). It is fixed and held by the X-ray tube support part (10) so that the long axis of the rectangular cross section is positioned parallel to the rotation axis (5). The X-rays emitted from the X-ray tube (9) are divergent light, but the incident X-rays (8) have a substantially linear thin rectangular cross section when they are emitted from the narrow X-ray extraction window of the X-ray tube (9). X-ray beam. Even if the incident X-ray (8) is incident on the sample (1) while the rectangular cross section of the incident X-ray (8) remains the same size as that at the time of emission, A wide area of the sample surface can be illuminated uniformly. Therefore, the incident angle at which the incident X-ray (8) is incident on the sample surface is a low angle of about 0 to 3 degrees with respect to the sample surface (however, the angle does not necessarily have to be smaller than 3 degrees). The X-ray tube (9) is fixed and held so as to form a so-called thin film arrangement.

  On the incident X-ray optical path between the X-ray tube (9) and the sample (1), there is no monochromator for monochromatization or optical elements for parallelization. Thereby, the X-ray tube (9) can be arranged as close as possible to the measurement area (A) as long as it does not contact the sample (1) or the sample support (2). The extent to which the X-ray tube (9) is actually arranged close to the measurement area (A) depends on whether the sample (1) or its supporting part or the two-dimensional position sensitive detector (3) is the X-ray tube (9 ) And where it physically comes into contact, but can be set to about 50 mm to 70 mm, for example. At this time, the use of the above-described thin film arrangement allows the entire measurement area (A) to be illuminated uniformly with the incident X-ray (8) even if the X-ray tube (9) is brought close to the sample (1). Is advantageous. By arranging the X-ray tube (9) and the sample (1) in close proximity in this way, attenuation of incident X-rays by the atmosphere can be suppressed as much as possible without introducing a vacuum path. It is also a great advantage that no optical element is disposed on the incident X-ray optical path, thereby eliminating the intensity attenuation caused by the optical element. The incident X-ray (8) remains divergent light generated in the X-ray tube (9) because it does not go through the optical element, but the X-ray tube (9) is placed very close to the sample (1). The influence of the incident X-ray (8) on the diffracted X-ray pattern acquired that is divergent light can be ignored.

The above-described measured region (A) is a region that the two-dimensional position sensitive detector (3) expects when the sample surface is viewed as a two-dimensional surface, that is, the two-dimensional position sensitive detector (3). It refers to the area formed by the point where the diffracted X-ray (6) that can be detected is emitted. That is, when the incident X-ray (8) enters the inside of the sample and the diffracted X-ray (6) is generated inside the sample, and the diffracted X-ray (6) is emitted from the sample surface, Only the diffracted X-rays (6) emitted from any part in the measured region (A) when viewed as a plane are detected by the detection element of the detector (3). Further, the emission part (exit position) is determined as the generation position of the diffracted X-ray (6). At that time, the deviation between the actual generation position and the emission position in the sample on the sample surface is only an error that can be ignored with respect to the resolution of the detector. Since the two-dimensional position sensitive detector (3) detects only the diffracted X-rays (6) that have passed through the angle divergence limiting means (7), the area to be measured (A) is the two-dimensional position sensitive detector (3). ) Is approximately the same size as the detector surface. For example, if the detector surface of the two-dimensional position sensitive detector (3) is 10 mm square, the area to be measured (A) is also approximately 10 mm square. Therefore, in this case, the distance between the X-ray tube (9) and the sample (1) is set as close as possible so that the incident X-ray (8) uniformly illuminates a 10 mm square region at a time. Therefore, it is necessary to determine the incident angle of the incident X-ray (8) with respect to the sample surface. Therefore, it is advantageous if the X-ray tube support part (10) is provided with an X-ray tube position adjusting mechanism therefor. However, there may be a case where the X-ray tube position adjusting mechanism is not necessary, for example, when only samples having substantially the same size and shape are measured. Since the sample is not moved during the measurement while scanning the detector position at an angle, the distance between the X-ray tube (9) and the sample (1) is also fixed during the measurement.

  The closer the distance between the sample surface and the detector surface (distance between the sample and the detector), the more efficiently the diffracted X-ray (6) can be detected, and a diffracted X-ray image can be acquired in a short time. This does not mean that measurement cannot be performed unless the sample surface and the detector surface are placed as close as possible. Therefore, this distance is the position closest to the sample surface within the range in which the two-dimensional position sensitive detector (3) and the angle divergence limiting means (7) rotating integrally therewith do not block the incident X-ray (8). Although the reference is used, a position farther away may be selected in consideration of avoiding contact with other members of the apparatus.

  Since the X-ray diffraction analyzer according to the invention of this application is an apparatus whose first purpose is to obtain distribution information of different structures existing in a sample by acquiring a diffraction X-ray intensity distribution image, Focus on structures with a specific lattice spacing, rather than using a wide range of scattering angles to obtain diffraction angles and diffracted X-ray intensities there, as with normal powder X-ray diffraction methods. By performing continuous or step scanning of the angle near the theoretical diffraction angle position corresponding to the lattice spacing, the distribution of the structure having the lattice spacing in the sample, the theoretical diffraction angle, and the actual diffraction It is more effective to observe the deviation from the angle. In particular, when specializing in the latter method of use, the rotational angle range of the two-dimensional position-sensitive detector (3) can be limited, and there is an advantage that the apparatus can be miniaturized.

  A method of using the latter method using the X-ray diffraction analyzer according to the invention of this application, that is, a method for acquiring a diffraction X-ray image representing the distribution of a specific crystal structure in a sample. Shown below. First, focusing on a specific lattice plane of the crystal structure, a scattering angle corresponding to a theoretical diffraction angle corresponding to the plane spacing of the lattice plane (an angle formed by the optical axis of incident X-rays and the optical axis of diffracted X-rays). ) Move the two-dimensional position sensitive detector (3) to the position. While irradiating the incident X-ray (8), the optimal angular position is searched while continuously scanning the rotational position (scattering angular position) of the two-dimensional position sensitive detector (3) around this position. When a diffracted X-ray image is acquired, a diffracted X-ray intensity distribution is obtained for the lattice plane of interest. From that image, it is possible to specify in which part of the sample (1) the crystal structure of interest is observed. On the other hand, diffracted X-rays are respectively detected at a plurality of detector rotation angle positions around the detector rotation angle position corresponding to the theoretical diffraction angle, using angle scanning by the two-dimensional position sensitive detector (3) as step scanning. It is also conceivable to obtain an image. The reason for scanning the scattering angle position is that the theoretical diffraction angle and the actual diffraction angle do not always coincide with each other. Here, since the diffraction angle is the angle with respect to the optical axis of the incident X-ray (8), the diffraction angle of the diffracted X-ray (6) with respect to the sample surface coincides unless the incident angle of the incident X-ray (8) is 0 degree. do not do.

In determining the distance between the sample and the detector, although there is a range depending on the purpose, it is necessary to perform the angle scan of the detector as described above, and the distance between the sample and the detector is fixed during the angle scan. With this in mind, care must be taken so that contact between members does not occur and incident X-rays (8) are not blocked at the maximum and minimum angles of the angular scanning range. In the case of the thin film arrangement, the distance between the sample and the detector is 90 ° when the detector surface of the two-dimensional position sensitive detector (3) faces the sample surface (the angle of emission of the diffraction X-ray (6) with respect to the sample surface is 90). ), The X-ray diffraction analyzer according to the invention of this application has the highest detection efficiency. is there. Depending on the structure of the apparatus used and the shape and size of the sample, this arrangement can shorten the distance between the sample and the detector to about 2 to 5 mm. On the other hand, when the two-dimensional position sensitive detector (3) is rotated so that the emission angle of the diffracted X-ray (6) detectable from this position is increased or decreased, the sample surface and the detector are detected. If the distance from the surface is not separated, contact with members such as the sample (1), sample support part (2), X-ray tube (9), X-ray tube support part (10) and incident X-rays (8) are blocked. The problem will arise. Accordingly, the two-dimensional position sensitive detector (3) is moved about ± 3 from the position facing the sample surface.
At the position rotated by 0 degrees, the distance between the sample and the detector is approximately 12 to 15 mm. However, it does not mean that measurement cannot be performed if it is further away. Considering that the distance between the sample and the detector is not too far away, the choice to use only diffracted X-rays (6) having an exit angle in the range of 60 to 120 degrees with respect to the sample surface, that is, a two-dimensional position It is fully conceivable that the rotational angle range of the sensitive detector (3) is limited to this range. The grating plane that can detect the diffracted X-rays (6) within this angular range should be selected as the grating plane of interest.

  Since the X-ray tube (9) is replaceable, an X-ray tube that generates characteristic X-rays having an appropriate X-ray energy (wavelength) according to the object to be measured is selected from a plurality of X-ray tubes. For example, even if the rotation angle range of the two-dimensional position sensitive detector (3) is limited, a sufficiently wide range of samples can be handled. For example, a chromium Kα ray (5414 eV) from a chromium tube, an iron Kα ray (6403 eV) from an iron tube, a copper Kα ray (8047 eV) from a copper tube, and the like are selected based on the following two criteria. First, a diffraction angle (corresponding to the lattice spacing of interest within a rotation angle range around the rotation axis (5) in which the two-dimensional position sensitive detector (3) can move ( The diffracted X-ray (6) having the angle formed by the incident X-ray (8) and the diffracted X-ray (6), that is, the scattering angle, is selected. As a guideline from the point of intensity of the diffracted X-ray (6), the angle of emission of the diffracted X-ray (6) from the target lattice plane with respect to the sample surface is 60 to 120 degrees, preferably around 90 degrees. An X-ray tube (9) that generates a characteristic X-ray with a wavelength may be selected. Second, paying attention to the absorption edge of the main component element in the sample, characteristic X-rays having a wavelength longer than the absorption edge wavelength (lower X-ray energy) so that the diffraction image is not buried in the background of fluorescent X-rays. Select the X-ray tube (9) that generates

  Characteristic X-rays generated by the X-ray tube (9) include Kβ rays and the like in addition to Kα rays. If the X-ray diffraction pattern to be acquired is adversely affected by including Kβ rays, the Kβ rays may be eliminated by using a filter material that absorbs Kβ rays as the extraction window of the X-ray tube 9. At this time, in order to arrange the X-ray tube (9) and the sample (1) close to each other, an optical element that absorbs Kβ rays is not provided on the optical path of the incident X-ray, but the X-ray tube (9) is not provided. It is important to form part of the X-ray extraction window with a material that absorbs Kβ rays. As a filter material, a metal foil of titanium is promising for a chromium tube, manganese for an iron tube, nickel for a copper tube, and the like.

  In FIG. 1, the sample support part (2) is illustrated on the assumption that the X-ray diffraction analyzer according to the invention of this application is used in a laboratory, but the role of the sample support part (2) is the sample ( Since 1) is fixed and held so as not to move, the sample support part (2) is naturally unnecessary if it is a part of the structure to which the sample (1) is fixed. In such a case, since the position of the sample cannot be moved from a fixed position, an X-ray tube (9), a two-dimensional position sensitive detector (3) depending on the location of the measurement region to be observed. Etc. will be placed in the optimum position. On the other hand, in the case of an apparatus intended for use in a laboratory, the position of the rotation axis (5) relating to the rotation of the two-dimensional position sensitive detector (3) is determined, and the rotation axis (5) Takes the procedure of adjusting the sample position so that the position of the sample passes through the center of the measurement area (A) in the same plane as the measurement area (A), and finally determining the position of the X-ray tube (9). Good. In an apparatus for use in the laboratory, if the apparatus is configured so that the surface of the sample (1) is horizontal, even an unstable sample such as a precipitate from a solution is measured. Can be targeted.

  As the two-dimensional position sensitive detector (3), a multi-element semiconductor detector, a CCD camera having an X-ray detection capability, a CMOS image sensor, or the like can be used. In a CCD camera or a CMOS image sensor capable of directly detecting X-rays, it is possible to distinguish between diffracted X-rays and fluorescent X-rays by determining the detected X-ray energy from the amount of generated charges. On the other hand, there is no problem in practicing the invention of this application even if the detector has a scintillator that emits light by X-rays instead of directly detecting X-rays and detects the light emission of the scintillator. .

  The image forming / recording unit generally includes a computer as a part thereof, but may be configured by incorporating the function of the computer as a microchip in the two-dimensional position sensitive detector (3).

It is a conceptual diagram of the X-ray diffraction analyzer which concerns on invention of this application.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sample 2 Sample support part 3 Two-dimensional position sensitive detector 4 Detector support part 5 Rotation axis regarding rotation of two-dimensional position sensitive detector 6 Diffracted X-ray 7 Angle divergence limiting means 8 Incident X-ray 9 X-ray tube 10 X-ray tube support section A Measurement area

Claims (7)

An X-ray tube for generating a characteristic X-ray of a predetermined element as an incident X-ray that illuminates the sample, an X-ray diffraction pattern including local structure information of the sample having a non-uniform crystal structure that is fixed and held, and two-dimensional In an X-ray diffraction analyzer for acquisition using a two-dimensional position sensitive detector consisting of a plurality of detector elements arranged in
The X-ray tube is fixedly held at a position where the incident X-ray can illuminate the entire measurement region to be observed on the sample surface and close to the sample as long as it is not in contact with the sample. And
The two-dimensional position sensitive detector can be rotated around a rotation axis extending perpendicularly to the optical axis of incident X-rays through the center of the region to be measured on the sample surface, and two-dimensionally with the sample. The sample surface and the detector surface at a position where the detector surface of the two-dimensional position sensitive detector faces the sample surface using a mechanism for adjusting the distance between the position sensitive detector and the surface. Arranged so that the distance between and becomes 2-5 mm,
Limiting the angle divergence of the diffracted X-rays in order to distinguish and detect the diffracted X-rays diffracted by the sample and emitted from each part in the measurement area by different detection elements of the two-dimensional position sensitive detector. An angle divergence limiting means for rotating so as to rotate integrally with the two-dimensional position sensitive detector around the rotation axis;
An X-ray diffraction analysis apparatus comprising: an image forming recording unit that forms and records a two-dimensional diffracted X-ray image with each pixel value corresponding to the intensity of the diffracted X-ray detected by the detection element.   The X-ray tube is an X-ray tube that generates an X-ray beam having a linear thin rectangular cross section, the long axis of the rectangular cross section extends parallel to the rotation axis, and the sample surface and the incident X-ray The X-ray diffraction analyzer according to claim 1, wherein the X-ray tube is fixedly held so that an angle formed by the optical axis of the X-ray tube is 0 to 3 degrees.   The X-ray tube is replaceable, and can be used by selecting an X-ray tube from among a plurality of X-ray tubes that generate characteristic X-rays of different elements. X-ray diffraction analyzer described in 1.   The mechanism for adjusting the distance between the X-ray tube and the sample and the angle formed between the sample surface and the optical axis of the incident X-ray is provided. The X-ray diffraction analyzer as described in any one of Claims.   The X-ray extraction window of the X-ray tube is made of a filter material that absorbs Kβ rays out of characteristic X-rays generated in the X-ray tube. The described X-ray diffraction analyzer.   6. The rotation angle range of the two-dimensional position sensitive detector and the angle divergence limiting means is from a position of 60 degrees to a position of 120 degrees with respect to the sample surface. The X-ray diffraction analyzer as described in any one of Claims. An X-ray tube for generating a characteristic X-ray of a predetermined element as an incident X-ray that illuminates the sample, an X-ray diffraction pattern including local structure information of the sample having a non-uniform crystal structure that is fixed and held, and two-dimensional In an X-ray diffraction analysis method for obtaining using a two-dimensional position sensitive detector composed of a plurality of detector elements arranged in a
Illuminating the entire region to be measured to be observed on the sample surface by incident X-rays emitted from an X-ray tube arranged close to the sample and incident on the sample;
By restricting the angular divergence of the diffracted X-rays diffracted by the sample and emitted from each part in the measured region, the diffracted X-rays emitted from each part are respectively detected by different detection elements of the two-dimensional position sensitive detector. Distinguishing and detecting, and
Using the mechanism for adjusting the distance between the sample and the two-dimensional position sensitive detector, the sample surface and the sample surface at a position where the detector surface of the two-dimensional position sensitive detector faces the sample surface. And about a rotation axis extending perpendicularly to the optical axis of incident X-rays through the center of the measurement area on the sample surface. Two-dimensional position-sensitive detector is rotated and moved to hold the two-dimensional position-sensitive detector at a desired angular position, and the intensity of diffracted X-rays detected by each detection element at that position is used as a pixel value. An X-ray diffraction analysis method comprising: forming and recording a diffraction X-ray image of

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