JP4019029B2 - Parallel X-ray beam extraction method and apparatus, and X-ray diffraction apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for extracting parallel X-ray beams of two types of wavelengths using a parabolic multilayer mirror. The present invention also relates to an X-ray diffraction apparatus provided with such a parallel X-ray beam extraction apparatus.

As a conventional technique for extracting parallel X-ray beams of two types of wavelengths, the one described in the following Patent Document 1 is known.
JP 2002-39970 A

  This known technique makes it possible to easily use X-rays having different wavelengths in measurement using X-rays. That is, it is characterized by comprising a plurality of X-ray generation means. In order to use parallel beams of two types of wavelengths, an X-ray source for the first wavelength, a dedicated parabolic multilayer mirror, A two-wavelength X-ray source and a dedicated parabolic multilayer mirror are used.

  In order to switch the wavelength of X-rays, the above-mentioned known technique must prepare a combination of an X-ray source and a dedicated parabolic multilayer mirror for each X-ray wavelength.

  The present invention has been made to solve the above-described problems, and a method and apparatus capable of extracting parallel X-ray beams of two types of wavelengths using a single parabolic multilayer mirror, and X-rays. It is to provide a diffraction device.

The parallel X-ray beam extraction method of the present invention includes the following steps. (A) A step of preparing a parabolic multilayer mirror including a reflective surface having a parabolic shape and a lamination period determined based on the first wavelength. (B) A first X-ray focal point that generates X-rays of the first wavelength is disposed at a focal position of the paraboloid, and the first wavelength of the first wavelength emitted from the first X-ray focal point Reflecting X-rays with the parabolic multilayer mirror to obtain a parallel X-ray beam having the first wavelength; (C) A second X-ray focal point that generates X-rays having a second wavelength different from the first wavelength is perpendicular to both the direction of the paraboloid axis and the direction in which the apex of the paraboloid extends. The X-ray having the second wavelength emitted from the second X-ray focal point is reflected by the parabolic multilayer mirror, and is disposed at a position shifted by a predetermined distance in the direction. Obtaining a parallel X-ray beam;

The parallel X-ray beam extraction apparatus of the present invention has the following configuration. (A) A parabolic multilayer mirror including a reflective surface having a parabolic shape and a lamination period determined based on a first wavelength. (B) A first X-ray focal point that can be disposed at the focal point of the paraboloid and generates X-rays of the first wavelength. (C) A second position different from the first wavelength can be arranged at a position shifted by a predetermined distance in a direction perpendicular to both the direction of the axis of the paraboloid and the direction in which the apex of the paraboloid extends . A second X-ray focal point that generates X-rays of a wavelength.

Furthermore, the X-ray diffractometer of the present invention uses the parallel X-ray beam extraction device described above, and diffracts the sample by irradiating the sample with the X-ray beam emitted from the X-ray source and diffracting the sample. An X-ray diffractometer that detects X-rays with an X-ray detector has the following configuration. (A) A parabolic multilayer mirror including a reflective surface having a parabolic shape and a lamination period determined based on the first wavelength. (B) A first X-ray focal point that can be disposed at the focal point of the paraboloid and generates X-rays of the first wavelength. (C) A second position different from the first wavelength can be arranged at a position shifted by a predetermined distance in a direction perpendicular to both the direction of the axis of the paraboloid and the direction in which the apex of the paraboloid extends . A second X-ray focal point that generates X-rays of a wavelength. (D) The X-ray source capable of realizing the first X-ray focal point and the second X-ray focal point.

  Furthermore, the X-ray diffractometer of the present invention can be combined with a switching method between the concentrated method and the parallel beam method. (A) A first incident path through which the X-ray beam is incident on the sample at a predetermined divergence angle. (B) A second incident path through which the X-ray beam is reflected by the parabolic multilayer mirror to be collimated and then incident on the sample. (C) A selective slit device capable of opening any one of the first incident path and the second incident path and blocking the other. (D) For the X-rays of the same wavelength, the X-rays are arranged so that the X-ray generation position does not change between the case where the first incident path is used and the case where the second incident path is used. Radiation source. (E) Sample support arranged so that the center position of the sample does not change between the case where the first incident path is used and the case where the second incident path is used for X-rays having the same wavelength. apparatus.

  When the parallel X-ray beam extraction method of the present invention is used, parallel X-ray beams of two types of wavelengths can be extracted using a single parabolic multilayer mirror.

First, the multilayer mirror used in the present invention will be described. The reflective surface of the multilayer mirror has a parabolic shape, and the relative positional relationship between the multilayer mirror and the X-ray source is determined so that the X-ray source is located at the focal position of the paraboloid. The X-ray beam emitted from the X-ray source and reflected by the reflecting surface becomes a parallel beam. This reflective surface consists of an artificial multilayer film in which heavy and light elements are alternately stacked, and the stacking period (corresponding to the lattice spacing of the crystal) changes continuously along the paraboloid ( (It becomes the slant lattice spacing) A parabolic multilayer mirror made for a specific wavelength satisfies the Bragg diffraction condition at all positions on the reflecting surface for X-rays of that wavelength. This type of parabolic multilayer mirror is disclosed in, for example, the following Patent Document 2.
JP-A-11-287773

  This multilayer mirror is also a monochromator because it selectively reflects only X-rays of a specific wavelength to form a parallel beam.

  FIG. 5 is a list showing that the specifications of the parabolic multilayer mirror differ depending on the target material of the X-ray tube. Depending on the material of the target (that is, the wavelength of the characteristic X-rays emitted from the target), the curvature and stacking period of the parabolic multilayer mirror are different. In the multilayer mirror in this list, the same value is used for the stacking period d. This list is for Kα characteristic X-rays of each target material, but when using other characteristic X-rays such as Kβ (the same material has a wavelength different from Kα), it is also dedicated to it. It is necessary to prepare a multilayer mirror.

  Next, the principle of the present invention will be described. FIG. 1 is a graph depicting a paraboloid 10 for CuKα rays and a paraboloid 12 for CoKα rays with the axes and vertices of the two paraboloids coinciding with each other. The horizontal axis of the graph is the distance X measured along the axis from the top of the paraboloid. The vertical axis is the distance Y measured in the direction perpendicular to the axis from the apex of the paraboloid. Strictly speaking, the focal point F of the paraboloids 10 and 12 exists slightly away from the apex position in the positive X direction, but the paraboloid of the parabolic multilayer mirror has a very flat shape. Therefore, the distance between the focal point F and the apex of the paraboloid is very small. Therefore, the focal point F is displayed at the position of the apex of the paraboloid.

  This parabolic multilayer mirror is designed to use a parabolic region where the distance X is 80 to 120 mm. Therefore, the CuKα ray that has emerged from the focal point F is reflected at a distance X = 80 to 120 mm on the paraboloid 10 and becomes a parallel beam. On the other hand, the CoKα ray exiting the focal point F is reflected at a distance X = 80 to 120 mm on the paraboloid 12 and becomes a parallel beam in the same manner.

  Next, in the graph of FIG. 1, let us consider that the paraboloid 12 is translated upward so that the two parabolas 10 and 12 intersect at X = 100 mm which is the center position of the multilayer mirror. FIG. 2 is a graph showing the result of the parallel movement. At point A at X = 100 mm, paraboloids 10 and 12 intersect. At this time, the paraboloid 12 is shifted upward by 0.6765 mm from the state shown in FIG.

  FIG. 3 is an enlarged view of the vicinity of X = 80 to 120 mm in the graph of FIG. At the point A, the two paraboloids 10 and 12 intersect. Thin lines 10 a and 10 b are drawn on both sides of one paraboloid 10, which indicates the allowable width of the paraboloid 10. This allowable width means that CuKα rays are reflected if a reflecting surface exists within the allowable width. The actual X-ray source has a finite focal width (for example, in the case of a normal focus X-ray tube, the focal width is 0.1 mm), and the reflection characteristic of the multilayer mirror is also a rocking curve width (for example, 0. 0 mm). It has an allowable error represented by about 05 °. These phenomena create the tolerances described above.

  Therefore, when the allowable width of the parabolic surface 10 of the CuKα ray is compared with the parabolic surface 12 of the CoKα ray, the range of the parabolic surface 10 of the CuKα ray is within the range of X = 80 to 120 mm, which is the use region. It can be seen that the paraboloid 12 of the CoKα line is located within the allowable width. This means that within the range of X = 80 to 120 mm, CoKα rays can be reflected (a parallel beam can be taken out) using a parabolic multilayer mirror for CuKα rays. Yes.

  Returning to FIG. 2, the CuKα ray emitted from the first X-ray focal point XF1 located at the focal point of the paraboloid 10 is reflected by the reflecting surface indicated by the paraboloid 10 in the region of X = 80 to 120 mm. Then, it becomes a parallel beam and goes out to the right. When the second X-ray focal point XF2 is provided at a distance of 0.6765 mm upward from the first X-ray focal point XF1, the CoKα ray emitted from the second X-ray focal point XF2 is X = In the region of 80 to 120 mm, the light is reflected by the reflecting surface indicated by the same paraboloid 10 and exits in the right direction as a parallel beam. Thus, the CuKα line and the CoKα line are reflected by the same reflecting surface, and the parallel beam extraction positions almost overlap each other.

  As described above, when the two wavelengths are appropriately selected, parallel X-ray beams of the two wavelengths can be separately extracted using the same parabolic multilayer mirror. Other combinations are possible in addition to the above-described combinations (taking out CoKα rays using a CuKα ray mirror). For example, CuKα rays and FeKα rays can be taken out using a CoKα ray mirror.

  Next, an X-ray tube used when implementing the present invention will be described. The most common method is to use separate x-ray tubes for the two x-ray wavelengths. In this case, for example, an X-ray tube having a Cu target and an X-ray tube having a Co target are set so as to be movable on the same frame, and the corresponding X-ray tube is set according to the wavelength used. 2 may be arranged at the position of the first X-ray focal point XF1 or the second focal point XF2 in the graph of FIG.

  An example in which a parallel beam extraction method using two X-ray tubes is applied to an X-ray diffractometer will be described with reference to FIG. A rotating anti-cathode X-ray tube 70 provided with a Cu target and a rotating anti-cathode X-ray tube 71 provided with a Co target are prepared. The parabolic multilayer mirror 20 includes a reflecting surface 10 made of a parabolic surface designed for CuKα rays as shown in FIG. In order to use CuKα rays for X-ray diffraction measurement, as shown in FIG. 6A, the two X-ray tubes 70 and 71 are moved, and the focal position of the Cu target X-ray tube 70 is changed to a parabolic multilayer film. It is brought to the position XF1 of the focal point of the paraboloid of the mirror 20, that is, the position of the first X-ray focal point XF1 in FIG. When only the X-ray tube 70 is operated, CuKα rays generated from the X-ray tube 70 are reflected by the multilayer mirror 20 and are output as a parallel beam 72. The sample 38 is irradiated with the parallel beam 72. The X-ray 74 diffracted by the sample 38 is detected by the X-ray detector 28 after passing through the solar slit 76.

  On the other hand, in order to use the CoKα ray for the X-ray diffraction measurement, as shown in FIG. 6B, the two X-ray tubes 70 and 71 are moved, and the focal position of the Co target X-ray tube 71 is set as shown in FIG. It comes to the position of the second X-ray focal point XF2. When only the X-ray tube 71 is operated, the CoKα ray generated from the X-ray tube 71 is reflected by the multilayer mirror 20 and is output as a parallel beam 72.

  Next, the use of a single X-ray tube capable of generating X-rays of two types of wavelengths will be described. FIG. 7 is a perspective view of a zebra-type rotating counter cathode 64. Cu target material 56 and Co target material 58 are alternately arranged on the outer peripheral surface of the rotating counter cathode 64 along the circumferential direction. When the rotating cathode 64 is irradiated with the electron beam 62 from the filament 60, the X-ray from the Cu target material 56 and the X-ray from the Co target material 58 are mixed and extracted as an X-ray beam 66. In this case, when viewed from the X-ray extraction direction, X-rays from the Cu target material 56 and X-rays from the Co target material 58 are generated from the same focal position.

  In the state shown in the figure, the X-ray beam 66 is generated from the position of the first X-ray focal point XF1 as viewed from above. The X-ray beam 66 includes a CuKα ray and a CoKα ray. Of these, only the CuKα ray satisfies the reflection condition of FIG. 2, and only the parallel beam of the CuKα ray is obtained from the multilayer mirror. It is taken out. On the other hand, in order to extract the CoKα line from the multilayer mirror, the rotating counter cathode 64 is shifted to the position of the alternate long and short dash line in FIG. Thus, the X-ray beam 68 is generated from the position of the second X-ray focal point XF2. This X-ray beam 68 also includes CuKα ray and CoKα ray. Of these, only CoKα ray satisfies the reflection condition of FIG. 2, so that only the parallel beam of CoKα ray is obtained from the multilayer mirror. Is taken out.

  Next, FIG. 8 shows an example in which the parallel beam extraction method using the X-ray tube shown in FIG. 7 is applied to an X-ray diffractometer. The X-ray tube 73 is an X-ray tube including the rotating counter cathode 64 shown in FIG. The parabolic multilayer mirror 20 includes a reflecting surface made of a parabolic surface 10 designed for CuKα rays as shown in FIG. To use CuKα rays for X-ray diffraction measurement, as shown in FIG. 8A, the X-ray tube 73 is moved so that the focal position of the X-ray tube 73 is changed to the parabolic surface of the parabolic multilayer mirror 20. 2, that is, the position of the first X-ray focal point XF 1 in FIG. Then, among the X-rays generated from the X-ray tube 73, only the CuKα ray is reflected by the multilayer mirror 20 and goes out as a parallel beam 72. The parallel beam 72 is irradiated onto the sample 38 and the X-ray 74 diffracted by the sample 38 passes through the solar slit 76 and is detected by the X-ray detector 28.

  On the other hand, in order to use CoKα rays for X-ray diffraction measurement, as shown in FIG. 8B, the X-ray tube 73 is moved, and the focal position of the X-ray tube 73 is changed to the second X-ray focus of FIG. Bring it to the XF2 position. Then, only the CoKα ray of the X-rays generated from the X-ray tube 73 is reflected by the multilayer mirror 20 and goes out as a parallel beam 72.

Next, an example in which the parallel beam extraction method of the present invention is combined with a switching method between the concentration method and the parallel beam method will be described. The following Patent Document 3 discloses a technique that can easily switch between a parallel beam incident optical system using a parabolic multilayer mirror and a concentrated incident optical system.
JP 2003-194744 A

  In this technique, it is possible to switch between the parallel beam method and the concentration method only by switching the selective slit device without changing the positional relationship between the X-ray source and the sample. Such a technique can be combined with the parallel beam extraction method of the present invention. FIG. 4 is a graph in which a concentrated X-ray path that can be switched to a parallel beam is added to the graph of FIG.

  When using a parallel beam of CuKα rays, the X-ray emitted from the first X-ray focal point XF1 is reflected by the parabolic multilayer mirror 20 and taken out as a parallel beam. When performing the concentration method measurement using the same CuKα ray, the divergent X-ray 22 emitted from the first X-ray focal point XF1 is used. On the other hand, when a parallel beam of CoKα rays is used, the X-ray emitted from the second X-ray focal point XF2 is reflected by the parabolic multilayer mirror 20 and extracted as a parallel beam. When performing the concentration method measurement using the same CoKα ray, the divergent X-ray 24 emitted from the second X-ray focal point XF2 is used. In this way, it is possible to switch between the parallel beam method and the focused method for two X-ray wavelengths, respectively.

  FIG. 9 shows an example in which an incident X-ray optical system that combines the parallel beam extraction method of the present invention and the switching method between the focusing method and the parallel beam method is applied to an X-ray diffractometer. FIG. 9 shows four types of incident optical systems in which two types of wavelengths, that is, CuKα ray and CoKα ray, and two types of methods, that is, a concentrated method and a parallel beam method, are combined. In this example, a rotating anti-cathode X-ray tube 70 provided with a Cu target and a rotating anti-cathode X-ray tube 71 provided with a Co target are used. The parabolic multilayer mirror 20 includes a reflecting surface made of a parabolic surface 10 designed for CuKα rays as shown in FIG. Between the X-ray tubes 70 and 71 and the sample 38, the aperture slit plate 14, the multilayer mirror 20, the selective slit device 18, and the diverging slit 40 are arranged in this order from the X-ray tube side.

  FIG. 10 is a perspective view of the aperture slit plate 14 and the multilayer mirror 20. The aperture slit plate 14 is fixed to the end face of the multilayer mirror 20 with screws, and both are integrated. A first opening 44 and a second opening are formed in the aperture slit plate 14, and the X-ray beam 46 that has passed through the first opening 44 is directed to the sample as it is. The X-ray beam 48 that has passed through the second opening 45 is reflected by the reflecting surface 50 of the multilayer mirror 20 to become a parallel beam 72 and travels toward the sample.

  FIG. 11 is a perspective view of the selective slit device 18. In FIG. 11 (a), the selective slit device 18 has a substantially disk shape and is provided with one elongated opening 52 in the vicinity of the center thereof. The selection slit device 18 can be rotated 180 ° around the rotation center line 54. The formation position of the opening 52 is eccentric with respect to the center 78 of the selective slit device 18. In the state of FIG. 11A, the opening 52 is located on the left side of the rotation center line 54. When the selection slit device 18 in this state is rotated by 180 ° around the rotation center line 54, the state shown in FIG. 11B is obtained, and the opening 52 is positioned on the right side of the rotation center line 54. In the state of FIG. 11A, only the X-ray beam 46 for the concentration method can pass through the opening 52, and in the state of FIG. 11B, only the parallel beam 72 (parallel beam reflected by the multilayer mirror) is opened. Can pass through.

  Returning to FIG. 9A, in order to perform X-ray diffraction measurement by the parallel beam method using CuKα rays, first, the two X-ray tubes 70 and 71 are moved, and the focal position of the Cu target X-ray tube 70 is moved. To the position of the focal point of the parabolic surface of the parabolic multilayer mirror 20, that is, the position of the first X-ray focal point XF1 in FIG. And the selection slit apparatus 18 is made into the state of FIG.11 (b). When only the X-ray tube 70 is operated in this state, only the CuKα rays generated in the X-ray tube 70 that have passed through the second opening 45 of the aperture slit plate 14 are reflected by the multilayer mirror 20. This becomes a parallel beam 72, which passes through the opening 52 of the selective slit device 18. On the other hand, X-rays that have passed through the first opening 44 of the aperture slit plate 14 are blocked by the selective slit device 18. The diverging slit 40 is sufficiently widened so that the parallel beam 72 can pass through. The sample 38 is irradiated with the parallel beam 72 that has passed through the diverging slit 40. The X-rays diffracted by the sample 38 are detected by the X-ray detector after passing through the solar slit, as shown in FIG.

  FIG. 9B shows a case where X-ray diffraction measurement is performed by a concentration method using CuKα rays. The positions of the two X-ray tubes 70 and 71 are the same as those shown in FIG. The selection slit device 18 is rotated 180 ° around the rotation center line 54 to be in the state of FIG. When only the X-ray tube 70 is operated, only the X-ray beam 46 passing through the first opening 44 of the aperture slit plate 14 among the CuKα rays generated in the X-ray tube 70 is the opening 52 of the selective slit device 18. Pass through. The X-ray beam 46 is irradiated to the sample 38 after being limited to a desired divergence angle by the divergence slit 40. The opening width of the diverging slit 40 can be controlled by an electric motor, and the diverging slit 40 can move in a direction perpendicular to the traveling direction of the X-ray (that is, in the direction indicated by the arrow 80 in FIG. 9B). The X-ray diffracted by the sample 38 is detected by a concentration method detection system, which will be described later.

  FIG. 9C shows a case where X-ray diffraction measurement is performed by a parallel beam method using CoKα rays. First, the two X-ray tubes 70 and 71 are moved to bring the focal position of the Co target X-ray tube 71 to the position of the second X-ray focal point XF2 in FIG. The selection slit device 18 and the diverging slit 40 are the same as in the state of FIG. When only the X-ray tube 71 is operated, only the CoKα rays generated in the X-ray tube 71 that have passed through the second opening 45 of the aperture slit plate 14 are reflected by the multilayer mirror 20, and the parallel beam 72, and this is irradiated to the sample 38.

  FIG. 9D shows a case where X-ray diffraction measurement is performed by the concentration method using CoKα rays. The positions of the two X-ray tubes 70 and 71 are the same as those shown in FIG. The selection slit device 18 and the diverging slit 40 are the same as in the state of FIG. When only the X-ray tube 71 is operated, only the X-ray beam 46 that has passed through the first opening 44 of the aperture slit plate 14 among the CoKα rays generated in the X-ray tube 71 is the opening 52 of the selective slit device 18. , And the sample 38 is irradiated with the divergence slit 40 after being limited to a desired divergence angle.

  Regarding the switching between the focusing method and the parallel beam method, for the first wavelength (CuKα ray), the X-ray path shown in FIG. 9B is the first incident path, and the X-ray path shown in FIG. This is the second incident path. For the second wavelength (CoKα ray), the X-ray path shown in FIG. 9D is the first incident path, and the X-ray path shown in FIG. 9C is the second incident path. For the first wavelength, the X-ray generation position (XF1) does not change and the center position of the sample 38 does not change in the first incident path and the second incident path. Also for the second wavelength, the X-ray generation position (XF2) does not change and the center position of the sample 38 does not change in the first incident path and the second incident path.

  As described above, examples of using one X-ray tube and examples using two X-ray tubes have been shown for the X-ray source generating two types of wavelengths, but the present invention is not limited to this. For example, in FIG. 7, the X-ray extraction direction is changed from line extraction to point extraction (extracting X-rays in the vertical direction in the figure) so that the position of the filament 60 can be moved left and right. Even if the tube is not moved, the focal position of the X-ray can be shifted only by moving the filament 60. Further, the X-rays of the first wavelength and the X-rays of the second wavelength can be generated, and the X-ray generation position of the first wavelength and the X-ray generation position of the second wavelength are shown in FIG. If an X-ray tube that is shifted by a distance between the first X-ray focal point XF1 and the second X-ray focal point XF2 is used, the present invention can be realized without moving the X-ray tube at all. . Further, considering that the X-ray beam is refracted by the reflecting mirror, it is not necessary to arrange actual X-ray focal points at the first focal position XF1 and the second focal position XF2 in FIG. For example, when viewed from the multilayer mirror, the X-ray beam of the second wavelength generated from the second X-ray tube at another position is reflected as if the X-ray focus is at the second focus position XF2. You may make it inject into a multilayer film mirror via a mirror.

  Next, the configuration of the concentrated X-ray diffraction apparatus will be described with reference to FIG. Between the X-ray tube 36 and the sample 38, the aperture slit plate 14, the multilayer mirror 20, the selective slit device 18, and the diverging slit 40 are arranged in this order from the X-ray tube 36 side. The sample 38 is placed on the sample support 42, and the sample support 42 can rotate around the rotation center 43 of the goniometer. The light receiving slit 26 and the X-ray detector 28 are mounted on the detector support 30, and the detector support 30 can also rotate around the rotation center 43 of the goniometer. The light receiving slit 26 and the X-ray focal point 34 are positioned on the concentrating circle 32 of the goniometer. In order to perform the X-ray diffraction measurement by the concentrated method, the diffracted X-rays from the sample 38 are detected using the light receiving slit 26 and the X-ray detector 28. At that time, the sample 38 and the detector support 30 are rotated in conjunction with an angular velocity ratio of 1: 2 to obtain an X-ray diffraction pattern.

  In order to switch to the parallel beam method, as described above, the selection slit device 18 is rotated by 180 ° around the rotation center line, and the center of the diverging slit 40 comes to the center of the parallel beam from the multilayer mirror 20. Like that. In order to perform X-ray diffraction measurement by the parallel beam method, the light receiving slit 26 is removed from the detector support 30 or the opening width of the light receiving slit 26 is made very wide. A solar slit is disposed in front of the X-ray detector 28. In order to increase the detected X-ray intensity, the X-ray detector 28 is preferably close to the sample 38. Therefore, the X-ray detector 28 can slide in the longitudinal direction of the detector support 30.

Next, the use which uses two types of X-ray wavelengths properly is demonstrated. In the X-ray diffraction method, if the absorption coefficient of the sample with respect to the incident X-ray wavelength is large, (1) the fluorescent X-ray is generated and the background is increased, and (2) the X-ray penetrating power to the sample is small. As a result, the number of crystal grains contributing to diffraction decreases and the diffraction intensity decreases. Considering these points, it is important to select an X-ray wavelength having a small absorption coefficient for the sample substance. Therefore, an example of using the CuKα line and CoKα line properly will be described. When measuring the diffraction pattern of Al ₂ O ₃ powder, the diffraction X-ray intensity is higher and the measurement accuracy is higher when the parallel beam of CuKα rays is used than the parallel beam of CoKα rays. On the other hand, when measuring the diffraction pattern of Fe ₃ O ₄ powder, the diffracted X-ray intensity is higher and the background is lower when the parallel beam of CoKα is used than the parallel beam of CuKα. .

It is the graph which drew the paraboloid for CuKα rays and the paraboloid for CoKα rays by making the axes and vertices of the two paraboloids coincide with each other. It is a graph which shows the result of having translated the paraboloid for CoK alpha rays in FIG. It is the graph which expanded and showed the vicinity of X = 80-120 mm of the graph of FIG. It is the graph which added the X-ray path of the concentration method to the graph of FIG. It is a list of the specifications of the parabolic multilayer mirror according to the material of the target of an X-ray tube. It is a top view which shows two types of states of the X-ray-diffraction apparatus to which the parallel beam extraction method using two X-ray tubes is applied. It is a perspective view of a zebra type rotating counter cathode. It is a top view which shows two types of states of the X-ray-diffraction apparatus to which the parallel beam extraction method using the X-ray tube shown in FIG. 7 is applied. It is a top view which shows four types of states of the X-ray-diffraction apparatus provided with the incident X-ray optical system which combined the parallel beam extraction method of this invention, and the switching method of the concentration method and a parallel beam method. It is a perspective view of an aperture slit plate and a multilayer mirror. It is a perspective view of a selection slit device. It is a top view which shows the structure of the X-ray-diffraction apparatus of the concentration method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Paraboloid for CuKα rays 12 Paraboloid for CoKα rays 14 Aperture slit plate 18 Selective slit device 20 Parabolic multilayer mirror 22 Divergent X-ray from first focus 24 Divergence X from second focus Line 26 Light-receiving slit 28 X-ray detector 30 Detector support base 34 X-ray focus 36 X-ray tube 38 Sample 40 Diverging slit 42 Sample support base 44 First opening 45 Second opening 50 Reflecting surface 70 Cu target X-ray tube 71 Co target X-ray tube 72 Parallel beam 73 Cu and Co mixed target X-ray tube 74 Diffracted X-ray 76 Solar slit XF1 First X-ray focus XF2 Second X-ray focus

Claims (8)

A parallel X-ray beam extraction method comprising the following steps.
(A) A step of preparing a parabolic multilayer mirror including a reflective surface having a parabolic shape and a lamination period determined based on the first wavelength.
(B) A first X-ray focal point that generates X-rays of the first wavelength is disposed at a focal position of the paraboloid, and the first wavelength of the first wavelength emitted from the first X-ray focal point Reflecting X-rays with the parabolic multilayer mirror to obtain a parallel X-ray beam having the first wavelength;
(C) A second X-ray focal point that generates X-rays having a second wavelength different from the first wavelength is changed from the focal point of the paraboloid to an axis direction of the paraboloid and a vertex of the paraboloid. The X-ray having the second wavelength emitted from the second X-ray focal point is reflected by the parabolic multilayer mirror by being arranged at a position shifted by a predetermined distance in a direction perpendicular to both the extending directions. And obtaining a parallel X-ray beam of the second wavelength.   2. The method of extracting parallel X-ray beams according to claim 1, wherein the first X-ray focal point and the second X-ray focal point are in the same X-ray tube.   2. The method of extracting parallel X-ray beams according to claim 1, wherein the first wavelength is a CuKα ray and the second wavelength is a CoKα ray. A parallel X-ray beam extraction apparatus having the following configuration.
(A) A parabolic multilayer mirror including a reflective surface having a parabolic shape and a lamination period determined based on a first wavelength.
(B) A first X-ray focal point that can be disposed at the focal point of the paraboloid and generates X-rays of the first wavelength.
(C) A second position different from the first wavelength can be arranged at a position shifted by a predetermined distance in a direction perpendicular to both the direction of the axis of the paraboloid and the direction in which the apex of the paraboloid extends . A second X-ray focal point that generates X-rays of a wavelength. An X-ray diffractometer having the following configuration in an X-ray diffractometer that irradiates a sample with an X-ray beam emitted from an X-ray source and detects a diffracted X-ray diffracted by the sample with an X-ray detector.
(A) A parabolic multilayer mirror including a reflective surface having a parabolic shape and a lamination period determined based on the first wavelength.
(B) A first X-ray focal point that can be disposed at the focal point of the paraboloid and generates X-rays of the first wavelength.
(C) A second position different from the first wavelength can be arranged at a position shifted by a predetermined distance in a direction perpendicular to both the direction of the axis of the paraboloid and the direction in which the apex of the paraboloid extends . A second X-ray focal point that generates X-rays of a wavelength.
(D) The X-ray source capable of realizing the first X-ray focal point and the second X-ray focal point.   6. The X-ray diffractometer according to claim 5, wherein the X-ray source includes one X-ray tube capable of generating the first wavelength X-ray and the second wavelength X-ray. An X-ray diffraction apparatus characterized in that the first X-ray focal point and the second X-ray focal point can be selectively realized by moving the lens.   6. The X-ray diffraction apparatus according to claim 5, wherein the X-ray source includes a first X-ray tube that generates X-rays having the first wavelength and a second X-ray that generates X-rays having the second wavelength. An X-ray diffractometer comprising a X-ray tube, wherein the first X-ray focal point and the second X-ray focal point can be selectively realized by moving these X-ray tubes. 6. The X-ray diffraction apparatus according to claim 5, further comprising the following configuration.
(A) A first incident path through which the X-ray beam is incident on the sample at a predetermined divergence angle.
(B) A second incident path through which the X-ray beam is reflected by the parabolic multilayer mirror to be collimated and then incident on the sample.
(C) A selective slit device capable of opening any one of the first incident path and the second incident path and blocking the other.
(D) For the X-rays of the same wavelength, the X-rays are arranged so that the X-ray generation position does not change between the case where the first incident path is used and the case where the second incident path is used. Radiation source.
(E) Sample support arranged so that the center position of the sample does not change between the case where the first incident path is used and the case where the second incident path is used for X-rays having the same wavelength. apparatus.

Images