JP4359116B2 - Micro-part X-ray irradiation apparatus and micro-part X-ray irradiation method of X-ray diffractometer - Google Patents

Description

  The present invention relates to a micro part X-ray irradiation apparatus and a micro part X-ray irradiation method of an X-ray diffraction apparatus for guiding X-rays from a collimator to a micro area of a sample, and in particular, X which requires in-plane rotation of a sample. The present invention relates to a micro X-ray irradiation apparatus and a micro X-ray irradiation method of an X-ray diffraction apparatus suitable for a line diffraction apparatus.

  In general, when X-ray diffraction measurement with high resolution is performed in a short time with respect to a micro area of a sample, X-rays from the X-ray tube are focused on the micro area of the sample by a collimator called a pinhole collimator. Irradiation is performed.

Further, for example, according to Patent Document 1 below, a technique for increasing the intensity of X-rays focused on a sample by combining a specific monochromator and a microfocus X-ray source having a focal size of 30 μm or less has already been disclosed. Are known.
JP-A-11-326599

  By the way, when the X-ray diffraction measurement with high resolution is performed on the minute region of the sample as described above, the sample needs to be tilted at an inclination angle of about 15 to 30 degrees with respect to the incident beam. This means that if the incident beam can be incident at 90 degrees (incident X-ray and sample surface are perpendicular), the irradiation field will not expand, but in that case, the diffraction line will be blocked by the sample itself and measurement will not be possible. by. For this reason, there is a problem that the irradiation field in the inclined direction is expanded due to the inclination of the sample, and the detection sensitivity at the minute portion is lowered. This is because the number of crystals is particularly small in the minute part of the sample, and therefore in-plane rotation of the sample (so-called φ axis rotation) is necessary to detect the diffraction line with high sensitivity and high accuracy. However, in such a case, the change in the irradiation field caused by the inclination of the sample expands to four times or more the collimator diameter, making it impossible to detect the diffraction lines with high accuracy.

  Therefore, the present invention is suitable for an X-ray diffractometer that solves the above-described problems in the prior art, that is, that performs X-ray diffraction measurement with high detection sensitivity by performing in-plane rotation of the sample with respect to a minute region of the sample. It is another object of the present invention to provide an X-ray diffractometer micro-part X-ray irradiation apparatus and a method thereof.

  In order to achieve the above-described object, according to the present invention, first, an X-ray source, a collimator for guiding X-rays from the X-ray source to a minute region of the sample, and a sample holder capable of rotating at least the sample A micro X-ray irradiation apparatus used in an X-ray diffraction apparatus including a mechanism and an X-ray detector for detecting X-rays diffracted by the sample, the X-ray being irradiated from the collimator onto the surface of the sample X-ray irradiator for a small part of an X-ray diffractometer that makes an irradiation shape of the irradiation surface of the X-ray beam on the irradiation surface be a substantially circular constant irradiation region regardless of the inclination angle between the X-ray beam and the sample Is provided.

  Further, according to the present invention, the micro X-ray irradiation apparatus of the X-ray diffraction apparatus described above includes a pair of slits that intersect the X-ray beam emitted from the collimator, or the pair of slits The tip of the slit has a curved shape.

  In addition, according to the present invention, in order to achieve the above-described object, an X-ray source, a collimator for guiding the X-rays from the X-ray source to a minute region of the sample, and a sample holder capable of rotating the sample at least In an X-ray diffraction apparatus including a mechanism and an X-ray detector that detects X-rays diffracted by the sample, the irradiation shape of the X-ray beam irradiated on the surface of the sample from the collimator is There is provided a micro-part X-ray irradiation method of an X-ray diffractometer that makes a substantially circular constant irradiation region irrespective of the tilt angle between the X-ray beam and the sample.

  According to the present invention, it is preferable that the X-ray diffracting method of the X-ray diffracting apparatus described above is an X-ray diffracting apparatus that intersects a pair of slits with the X-ray beam emitted from the collimator. A method for irradiating a minute part X-ray is provided.

  As is clear from the above, according to the micro-part X-ray irradiation apparatus and micro-part X-ray irradiation method of the X-ray diffraction apparatus according to the present invention, in particular, detection is performed by performing in-plane rotation of the specimen with respect to the micro area of the specimen. In an X-ray diffractometer that realizes highly sensitive X-ray diffraction measurement, even if the sample is tilted at an inclination angle of about 15 to 30 degrees with respect to the incident beam, in-plane rotation (so-called φ axis rotation) of the sample is performed. It exhibits a technically excellent effect of enabling highly sensitive and highly accurate detection of diffraction lines without causing a change in the irradiation field.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First, in FIG. 4 attached, an example of a schematic configuration of a so-called micro X-ray diffractometer using a micro X-ray irradiation apparatus and a micro X-ray irradiation method according to an embodiment of the present invention is shown. Show.

  This micro X-ray diffractometer includes an X-ray source F (X-ray focal point) that emits X-rays, a monochromator 3 that monochromaticizes X-rays emitted from the X-ray source F, and the monochromator 3. A collimator 4 that takes out monochromatic X-rays as a parallel X-ray beam with a small cross-sectional diameter, a sample stage 1 that supports the sample S, and a sample surface of the sample S, for example, arranged to face the sample surface. And a PSPC (position sensitive proportional counter) 2 as an original X-ray detector.

  The sample S may itself be a minute sample, or may be a minute part of a sample having a certain size. The X-ray source F (X-ray focal point) is formed as a point-focused X-ray focal point, for example, and the monochromator 3 is composed of, for example, a flat graphite crystal. The collimator 4 forms a parallel X-ray beam having a small cross-sectional diameter, for example, having a cross-sectional diameter of about 10 to 100 μmφ.

  On the other hand, the sample table 1 is supported by an arc support table 6, which is supported by an in-plane slider 7, and the in-plane slider 7 is supported by a plane perpendicular slider 8. The sample stage 1 is provided with a φ rotating device 9 and driven by the φ rotating device 9 to rotate the sample S around the φ axis. This φ axis is an axis passing through a point where the optical axis X0 of the X-ray (that is, incident X-ray) R0 incident on the sample S and the sample S intersect, and so-called rotation when the sample S is rotated in the plane. This is the central axis.

  The arc support 6 is provided with a ω rotating device 11 and driven by the ω rotating device 11 to rotate the sample S around the ω axis. This ω-axis extends in the direction perpendicular to the paper surface of FIG. 4 and passes through the point where the incident X-ray optical axis X0 and the sample S intersect, and the incident angle θ of the incident X-ray R0 with respect to the sample S is This is the center of rotation when changing.

  The in-plane slider 7 is configured using a so-called XY slider that can freely translate in a horizontal plane, and the sample S can be translated in the plane by this translation. The inner surface slider 7 is driven by the in-plane driving device 12 to move.

  The right-angle slider 8 reciprocally translates in a direction perpendicular to the parallel movement direction of the inner surface slider 7, and in the case of FIG. 2, it can be configured using a slider that can reciprocate up and down. By this movement, the sample S can be moved in a direction perpendicular to the parallel movement direction of the in-plane slider 7. The right-angle slider 8 is driven by the right-angle drive device 13 and moves in parallel.

  The φ rotation device 9, the ω rotation device 11, the in-plane drive device 12, and the right-angle drive device 13 described above can each be configured using a drive mechanism having an arbitrary structure, but in general, for example, a pulse motor or the like A drive source is included.

  The PSPC 2 is a well-known one-dimensional X-ray detector. For example, an appropriate structure for inducing charges from the signal line 16 and the X-ray is stored in a curved casing 14 as shown in the figure. As a structure for inducing charges from X-rays, for example, a structure in which an anode line and a cathode line are arranged in parallel to the signal line 16 can be considered. An elongated opening 17 for taking in X-rays from a wide range in the X-ray diffraction angle (2θ) direction is provided on the surface of the casing 14 facing the sample S.

  The X-ray calculation circuit 18 for detecting the intensity and diffraction angle of the X-rays taken into the PSPC 2 is, for example, a position calculation circuit 19 for inputting signals from both ends of the signal line 16 as shown in the figure. The position / wave height conversion circuit 21 that converts the output signal of the position calculation circuit 19 into a peak wave height, and the X-ray intensity distribution relating to the diffraction angle (2θ) based on the output signal from the position / wave height conversion circuit 21. MCA (Multi-Channel Height Analyzer) 22 to be obtained. Connected to the output terminal of the MCA 22 are a display 23 for displaying the calculation result as an image and a printer 24 for printing out the calculation result on a printing material such as paper as necessary.

  Next, the principle of the micro X-ray irradiation apparatus and micro X-ray irradiation method according to the present invention will be described. As described above, in particular, in X-ray diffraction in a minute region, it is necessary to tilt the sample with respect to the incident beam at an inclination angle of about 15 to 30 degrees. For example, as indicated by reference numeral B in FIG. 5A, the shape of the incident beam on the sample surface obtained at substantially right angle incidence is a substantially circular shape that is substantially the same as the collimator diameter. However, when the sample is tilted at an inclination angle of about 15 to 30 degrees with respect to the incident beam, as shown in FIG. 5B, the shape C of the incident beam on the sample surface is the inclination direction of the sample surface. Therefore, in consideration of the in-plane rotation of the sample (so-called φ axis rotation), the irradiation field VF is expanded to more than four times the collimator diameter, and a highly accurate minute X-ray irradiation becomes impossible.

  Therefore, as shown in FIG. 1, when projecting X-rays radiated from the X-ray source F (X-ray focal point) onto, for example, the curved mirror M to obtain parallel incident X-rays, the parallel incident X-rays are obtained. A pair of slits 100, 100 are provided in the middle of the line to block part of incident X-rays having a substantially circular cross section. As a result, the shape of the incident X-ray obtained through the slits 100 and 100 is formed into a substantially elliptical shape with the minor axis in the direction in which the surface of the sample S is inclined. See MB).

  As a result, the shape of the incident X-ray irradiated on the surface of the micro part of the sample S is formed in a substantially circular shape as indicated by MC in the figure. That is, the cross-sectional shape of the incident X-rays from the collimator is not a circle but the aspect ratio thereof can be changed as appropriate (for example, 1: 2 when the incident angle θ is 30 degrees). This reduces the irradiation width of incident X-rays in the direction in which the sample is tilted (1/2 in the above example), so that the aspect ratio of the irradiation field on the sample surface can be made the same. Even if it is rotated in-plane, the irradiation field does not change. In the conventional method, for example, in order to obtain an irradiation field of 10 μmφ, a collimator of 5 μmφ is required. However, according to the micro-part X-ray irradiation apparatus and micro-part X-ray irradiation method of the present invention, 10 × 5 μm By obtaining an elliptical incident X-ray, the same irradiation field can be obtained. That is, the same irradiation field is obtained with twice the X-ray dose, and the intensity is doubled.

  Next, FIG. 2 attached more specifically shows an example in which the pair of slits 100, 100 are provided at or near the exit of the incident X-ray of the collimator 4 (the tip of the collimator). ing. The pair of slits 100, 100 are mounted on a member disposed at or near the tip of the injection port. For example, through a mechanism that can finely adjust its position, such as a screw mechanism, FIG. As shown by an arrow a, they can be close to each other or separated from each other. In other words, the substantially elliptical X-ray cross-sectional shape obtained by this micro X-ray irradiation apparatus can be appropriately changed in accordance with the change in the incident angle θ. The fine position adjustment mechanism for the pair of slits 100, 100 can be configured to be performed manually, or is automatically driven by a pulse motor or the like corresponding to the set incident angle θ. You may make it adjust. In general, the inclination angle (incident angle θ) of the sample with respect to incident X-rays is constant during measurement.

  Further, FIG. 3 attached here shows a specific shape of the pair of slits 100, 100. FIG. 3A shows an example in which the pair of slits 100 and 100 is formed of a rectangular plate-like member, and the broken line in the figure indicates the outer diameter of the incident X-ray from the collimator. ing. As is clear from this figure, according to the rectangular slits 100, 100, the outer diameter of the substantially circular incident X-ray is blocked from above and below, so that the shielding portion is particularly large (that is, the incident angle). When θ is small and the distance between the slits is small), the shape is far from the elliptical shape. Therefore, as shown in FIG. 3B, by forming the opposing end portions of the pair of slits 100, 100 in a curved shape, the incident X closer to an elliptical shape even if the shielding portion becomes larger. It becomes possible to obtain the cross-sectional outer diameter of the wire.

  In the above embodiment, the micro X-ray irradiation apparatus according to the present invention is used in the micro X-ray diffraction apparatus shown in FIG. 4, however, the present invention is limited to this. Without limitation, in particular, as a mechanism for mounting the sample and adjusting it to a desired angular position, for example, the mechanism shown in the attached FIG. 6 or FIG. 7 may be used instead of the above. .

  As described above, according to the present invention, in an X-ray diffractometer that measures a minute portion of a sample obliquely inclined with respect to incident X-rays while rotating the sample in-plane, the inclination angle of the sample is set. The X-ray irradiation area on the sample surface is set so that the portion (position) where the X-ray hits does not change even if the in-plane rotation is performed in a constant state, that is, in order to obtain a constant X-ray irradiation area. The shape is close to a substantially circular shape around the center of rotation of the sample. According to this, it is possible to make the irradiation area of the X-ray constant and to keep the irradiation place unchanged even if the surface of the sample is rotated by in-plane rotation.

  On the other hand, conventionally, when measuring a minute part, in order not to irradiate the surrounding extra part with X-rays, a collimator with a smaller diameter is expected in advance so that the irradiation field is widened. The X-ray intensity has become very weak because it has to be selected and used. On the other hand, in the present invention, as described in detail above, the incident X-ray is thinned only in the direction in which the irradiation shape extends, so that the irradiation shape becomes substantially circular. Even if it is rotated, the irradiation field does not change, and the X-ray intensity does not become too weak as in the prior art.

  Furthermore, in the above description, a method using a so-called slit has been described as an example of a specific method for limiting incident X-rays. However, the collimator itself has an elliptical exit. Is also possible. In this case, it is conceivable that a plurality of collimators having different elliptical flatness ratios are prepared in advance corresponding to the inclination angle of the sample, and appropriately selected and used depending on the setting of the inclination angle at the time of measurement. It may also be possible to measure using a single elliptical collimator within a range of tilt angles of a particular sample. Furthermore, regarding the slit, the variable slit as described above may be used. Alternatively, for example, a plurality of fixed slits having different widths are prepared in advance, and appropriate fixed slits are prepared according to the inclination angle of the sample. It is also possible to select.

It is a figure explaining the micro part X-ray irradiation apparatus and micro part X-ray irradiation method of the X-ray diffraction apparatus which become one embodiment of this invention. It is a partially expanded perspective view which shows the more specific example of the said micro part X-ray irradiation apparatus. It is a plain view explaining the specific shape of a pair of slit in the said micro part X-ray irradiation apparatus. It is a block diagram which shows an example of schematic structure of the micro part X-ray diffraction apparatus in which the said micro part X-ray irradiation apparatus and the micro part X-ray irradiation method are used. It is a figure for demonstrating the principle of the said micro part X-ray irradiation apparatus and the micro part X-ray irradiation method. It is a figure which shows the example of the other X-ray diffraction apparatus in which the said micro part X-ray irradiation apparatus and the micro part X-ray irradiation method are used. Again, it is a figure which shows the example of the other X-ray diffraction apparatus in which the said micro part X-ray irradiation apparatus and the micro part X-ray irradiation method are used.

Explanation of symbols

1 Sample stage (φ axis rotation)
100 slit 4 collimator 9 φ rotating device S sample MB elliptical incident X-ray from the slit MC circular incident X-ray on the sample.

Claims (5)

An X-ray source, a collimator for guiding X-rays from the X-ray source to a minute region of the sample, a sample holding mechanism capable of rotating at least the sample, and an X-ray detector for detecting X-rays diffracted by the sample A micro-part X-ray irradiation apparatus of an X-ray diffraction apparatus comprising:
In a state where the holding angle of the sample is held constant, the irradiation shape of the X-ray beam irradiated on the surface of the sample from the collimator is a substantially circular constant around the rotation center of the sample. An X-ray diffractometer for X-ray diffractometer, wherein the X-ray diffractometer is an irradiation region, and the irradiation location is not changed even if the surface of the sample is rotated.   The micro X-ray irradiation apparatus according to claim 1, further comprising a pair of slits intersecting the X-ray beam emitted from the collimator. Irradiation device.   3. The micro X-ray irradiation apparatus according to claim 2, wherein tip portions of the pair of slits have a curved shape for controlling an irradiation shape of the X-ray beam on the irradiation surface. X-ray diffractometer of X-ray diffractometer. An X-ray source, a collimator for guiding X-rays from the X-ray source to a minute region of the sample, a sample holding mechanism capable of rotating at least the sample, and an X-ray detector for detecting X-rays diffracted by the sample In the X-ray diffraction apparatus for X-ray diffractometer,
In a state where the holding angle of the sample is held constant, the irradiation shape of the X-ray beam irradiated on the surface of the sample from the collimator is a substantially circular constant around the rotation center of the sample. A method for irradiating a minute portion of an X-ray diffractometer, wherein the irradiation location is not changed even when the surface of the sample is rotated.   5. The micro X-ray irradiation method according to claim 4, wherein a pair of slits are crossed with the X-ray beam emitted from the collimator.

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