JP2008111836A - X-ray diffraction measuring method and x-ray diffraction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray diffraction device capable of acquiring sufficient diffraction line intensity in a 2θ high angle domain where the diffraction line intensity is weakened, when the sample quantity is small, and maintaining accurately relative X-ray intensity of a diffraction peak in a 2θ middle angle domain and in a 2θ low angle domain where the X-ray irradiation width is widened. <P>SOLUTION: In this X-ray diffraction device, an X-ray radiated from an X-ray source F is regulated by a divergence slit 2 and irradiated to the sample S, and a diffraction line R<SB>2</SB>emitted from the sample S is detected by an X-ray detector 10. A divergence angle of the divergence slit 2 is a fixed value, and the divergence slit 2 is a slit for restricting the X-ray irradiation width in the sample width direction. The sample S is arranged in a longitudinally-elongated manner wherein the sample width is smaller than a standard sample width and the sample height is the same as a standard sample height. The X-ray intensity I<SB>obs</SB>(θ) determined based on an output from the X-ray detector 10 is corrected based on an effective divergence angle calculated from the sample width, to thereby acquire the true X-ray intensity I<SB>tru</SB>(θ). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an X-ray diffraction measurement method and apparatus for performing X-ray diffraction measurement using a fixed divergent slit.

  In X-ray diffraction measurement, in general, a sample is irradiated with X-rays emitted from an X-ray source at an incident angle “θ”, and the diffraction lines emitted from the sample at a diffraction angle “2θ” are detected by an X-ray detector. The intensity I of the diffraction line is obtained based on the output signal of the X-ray detector. The diffraction angle “2θ” is always twice the incident angle “θ”. Considering the diffraction line intensity I as a function of the X-ray incident angle “θ”, the diffraction line intensity can be expressed as I (θ). If the diffraction line intensity I is considered as a function of the diffraction angle “2θ”, the diffraction line intensity can be expressed as I (2θ). In this specification, the notation of I (θ) is frequently used for convenience of explanation.

  In the above X-ray diffraction measurement, the X-rays emitted from the X-ray source are generally irradiated onto the sample in a state where the irradiation size in the sample width direction is regulated by a diverging slit (DS: Divergence Slit). . It has been widely known that the slit width (that is, the divergence angle) of the divergence slit is a fixed value in the X-ray diffraction measurement. For example, page 178 of Non-Patent Document 1 (Chapter 7 “Handling of Diffractometers and Spectrometers”, Section 7-3 “X-ray optics”) contains commonly used divergent slits. It is disclosed that the spread angle (that is, the divergence angle) is “1 °”, that is, the divergence angle is a fixed value.

  Further, in the description of the prior art in the detailed description of the invention of Patent Document 1 and FIG. 1 (the description is on page 2), the divergence angle of the divergence slit (referred to as “diffusion slit” in the document) is shown. A fixed value is disclosed. Hereinafter, a divergence slit having a fixed divergence angle is referred to as a fixed divergence slit, and a divergence slit having a variable divergence angle is referred to as a variable divergence slit.

B. D. CULLITY, Gentaro Matsumura, “Karity New Edition X-ray diffraction theory”, Agne, Inc., March 25, 1989, 7th edition, p. 178 Japanese Patent Laid-Open No. 50-63982 (2nd page, FIG. 1)

Conventionally, in an X-ray diffraction measurement performed using a fixed divergence slit, a sample is a standard sample region (standard sample width Wr × standard sample height) as indicated by reference numeral S in FIGS. 6 (a) and 6 (b). (Region defined by Hr). In a general X-ray diffractometer, Wr = Hr = 20 mm is often set. FIG. 6B is a cross-sectional view according to the Z ₆ -Z ₆ line of FIG. In these figures, the X-rays emitted from the X-ray source F are irradiated to the sample S in a state where the divergence is regulated by the divergence slit 101. When a diffraction line is generated from the sample S, the diffraction line is detected by the X-ray detector 102.

The X-rays irradiated on the sample S are shown in a rectangular shape by a chain line surrounding the sample S in FIG. The width of the X-ray that irradiates the sample S (this width is referred to as “X-ray irradiation width”) W ₀ is determined by the divergence angle “β” of the divergence slit 101 and the X-ray incident angle “θ”. FIG. 6B shows a case where the X-ray incident angle θ is a low angle, and accordingly, a case where the X-ray irradiation width W0> the standard sample width Wr is satisfied. FIG. 7C shows a case where the X-ray incident angle θ is a boundary angle, and the X-ray irradiation width W0 = sample width (standard sample width Wr in the figure). FIG. 7D shows the case where the X-ray incident angle θ is a high angle, and the case where the X-ray irradiation width W0 <the standard sample width Wr is satisfied.

  In FIG. 6A, the height of the X-rays that irradiate the sample S, that is, the length of the X-rays in the direction orthogonal to the X-ray irradiation width W0, clearly indicates the height and the standard sample height Hr. For the sake of illustration, it is drawn larger than the standard sample height Hr. However, in practice, the height of X-rays that irradiate the sample S is substantially the same as the standard sample height Hr. And such a situation with respect to the standard sample height Hr of the X-ray height which irradiates the sample S is the same also in each case of Fig.8 (a), FIG.8 (b), and FIG.9 (a). is there.

  When X-ray diffraction measurement is performed using a fixed divergent slit on a sample placed in the standard sample region (this sample is referred to as “standard packed sample”), the X-ray incident angle θ is set as shown in FIG. Scanning is performed from the low-angle region shown in b) to the high-angle region shown in FIG. 7D, and the diffraction lines from the sample S are detected by the X-ray detector 102 during the scanning.

  By the way, when actually performing X-ray diffraction measurement, a sufficient amount of sample may not be available. In this case, the entire standard sample region (Wr × Hr) shown in FIG. 6A cannot be filled with the sample S. In this case, as a method of arranging such a small amount of the sample S, two types, a method shown in FIG. 8A and a method shown in FIG.

  In the method of FIG. 8A, the sample width is set to the standard sample width Wr, and the sample height is set to Hs narrower than the standard sample height Hr. In this specification, this arrangement is referred to as “horizontal arrangement”. On the other hand, in the method of FIG. 8B, the sample width is set to Ws narrower than the standard sample width Wr, and the sample height is set to the standard sample height Hr. In this specification, this arrangement is referred to as “vertical arrangement”.

  In the case of the horizontally long arrangement shown in FIG. 8A, the relationship between the X-ray irradiation width W0 from the X-ray source F and the sample width Wr when the X-ray incident angle θ changes (see FIG. 6B) is a diagram. This is the same as the case of the standard packed sample shown in FIGS. 6B, 7C, and 7D, and the X-ray irradiation width is within the sample width within a wide range of the diffraction angle 2θ. In the region where the X-ray irradiation width does not exceed the sample width, the X-ray dose irradiated to the sample is the same, and the relative X-ray intensity (that is, the intensity ratio) of the peak in this region is correctly measured. In the diffraction angle region where the irradiation width exceeds the sample width, the effective X-ray dose decreases, and the relative intensity decreases.

  Here, the relative X-ray intensity of the peak is the ratio of the observed X-ray intensity measured to the true X-ray intensity. The true X-ray intensity is a measured X-ray intensity observed in a diffraction angle region where the irradiation width of incident X-rays applied to the sample does not exceed the sample width. That is, when all of the X-ray dose incident on the sample is irradiated within the range of the sample, a measured X-ray intensity that can be evaluated equivalent to the true X-ray intensity is observed.

  On the other hand, in the case of the vertically long arrangement, as can be understood from FIGS. 9B, 10C, and 10D, the X-ray irradiation width W0 is even when the X-ray incident angle θ is relatively high. It protrudes from the sample width Ws. When the X-ray irradiation width W0 protrudes from the sample width Ws, the X-rays irradiate an extra region other than the sample width. On the other hand, the X-ray dose for irradiating the sample width decreases. As a result, the X-ray intensity decreases, and there is a possibility that the peak of the diffraction line cannot be accurately determined.

  In view of such circumstances, when an X-ray diffraction measurement is to be performed on a small amount of sample, a person skilled in the art of the X-ray measurement field can obtain a correct relative X-ray intensity (intensity) within a wide diffraction angle 2θ region. It is common to select a horizontally long arrangement that can maintain the ratio). However, when the horizontally long arrangement is adopted, since the X-ray irradiation height always protrudes from the sample height Hs in FIG. 8A, the amount of the sample that can contribute to the diffraction is reduced. There is a problem that sufficient diffraction line intensity cannot be obtained on the high angle side of the angle θ. In order to obtain sufficient diffraction line intensity, it is necessary to perform measurement for a very long time, which is not realistic.

  The present invention has been made in view of the above circumstances, and in the case where a sample whose amount is smaller than the standard packed sample amount is a measurement object, sufficient diffraction is achieved in a 2θ high-angle region where the diffraction line intensity becomes weak. By maintaining the relative X-ray intensity (intensity ratio) of the diffraction line peak at a constant value in the 2θ medium angle region and 2θ low angle region where the X-ray irradiation width is widened. It is an object of the present invention to provide an X-ray diffraction measurement method and an X-ray diffraction apparatus that make it possible to acquire accurate diffraction line data.

  In the X-ray diffraction measurement method according to the present invention, (1) X-rays radiated from an X-ray source are controlled by a diverging slit and irradiated on a sample, and the diffraction lines emitted from the sample are detected by an X-ray detection means. In the X-ray diffraction measurement method, (2) the divergence angle of the divergence slit is a fixed value, (3) the divergence slit is a slit that regulates the X-ray irradiation width in the sample width direction, and (4) the sample is The sample width is narrower than the standard sample width and the sample height is the same as the standard sample height, and (5) the X-ray intensity obtained based on the output of the X-ray detection means is The correction is based on the effective divergence angle calculated from the sample width.

  According to the method of the present invention, since the fixed divergence slit is used as the divergence slit, the structure can be simplified and the cost can be reduced as compared with the case where the variable divergence slit is used as the divergence slit. Further, since the measurement is performed with the sample placed in a vertically long arrangement (see FIG. 8B), even when the amount of the sample is small, a higher angle region of 2θ than in the case of the horizontally long arrangement (see FIG. 8A). A strong diffraction line can be obtained (for example, 80 ° or more), and accurate diffraction data can be obtained in a short time.

  When the sample is placed in a vertically long arrangement, the X-ray irradiation width protrudes from the sample width not only in the low angle region of 2θ (for example, 20 ° or less) but also in the medium angle region of 2θ (for example, about 60 °), For this reason, the relative X-ray intensity (intensity ratio) of diffraction lines is not constant, and a situation in which correct diffraction line intensity cannot be obtained occurs. Therefore, even if a qualitative analysis is performed by comparing a diffraction profile obtained by measurement with respect to a vertically arranged sample with standard data (for example, ICDD card data) obtained in advance with respect to the standard sample, accurate analysis cannot be performed. This happens.

In this regard, in the present invention, the X-ray intensity I _obs determined based on the output of the X-ray detection means is corrected based on the effective divergence angle of the divergence slit calculated from the sample width of the sample. It is possible to compensate for a decrease in relative X-ray intensity (intensity ratio) in the 2θ low-angle region with respect to the arranged sample and to maintain the relative X-ray intensity constant. For this reason, when a qualitative analysis is performed by comparing the diffraction profile of a sample having a narrow sample width with the standard diffraction profile of a sample having a standard sample width, an accurate analysis result can be obtained.

Next, an example of the “effective divergence angle calculated from the sample width” will be described. In FIG. 11, the sample width of the sample S is “2A”, the X-ray incident angle to the sample S is “θ”, and the goniometer When the radius is “R”, the effective divergence angle “β” of the divergence slit 2 is
tan β = (sin θ) / (R / 2A) (1)
True X-ray when the actual divergence angle of the divergence slit 2 is “γ” and the X-ray intensity obtained based on the output of the X-ray detection means 10 is I _obs (θ). The intensity I _true (θ) is
I _true (θ) = (γ / β) I _obs (θ) (2)
It is desirable to obtain based on
The actual goniometer radius “R” varies depending on the type of goniometer, but typical values are 185 mm and 150 mm.

The above equation (2) is
β ≦ γ (3)
That is, it is effectively used when the effective divergence angle β of the divergence slit is equal to or smaller than the actual divergence angle γ. Further, at present, (1/6) °, (1/2) °, 1 °, 2 °, 4 °, etc. are used as the actual divergence angle γ of the divergence slit. These are appropriately selected according to which diffraction angle 2θ region the diffraction line from the sample to be measured appears.

Next, another example of the “effective divergence angle calculated from the sample width” will be described. In FIG. 12, the sample width of the sample S is “2A”, and the X-ray incident angle to the sample S is “θ”. When the goniometer radius is “R”, the effective divergence angle “β1” on the side farther from the X-ray source F than the sample width center C out of the effective divergence angle “β” of the divergence slit 2 and the effective divergence angle “ The effective divergence angle portion “β2” closer to the X-ray source F than the sample width center C in “β”
tan β1 = (sin θ) / {(R / A) −cos θ} (4)
tan β2 = (sin θ) / {(R / A) + cos θ} (5)
True X-ray when the actual divergence angle of the divergence slit 2 is “γ” and the X-ray intensity obtained based on the output of the X-ray detection means 10 is I _obs (θ). The intensity I _true (θ) is
I _true (θ) = {γ / (β1 + β2)} × I _obs (θ) (6)
It is desirable to obtain based on

The above equation (6) is
β1, β2 ≦ γ / 2 (7)
That is, when the effective divergence angle portions β1 and β2 are both equal to or smaller than ½ (ie, γ / 2) of the actual divergence angle.

  The method for specifying the effective divergence angle based on FIG. 12 includes a half on the side farther from the X-ray source F than the sample width center C (sometimes referred to as “the right side of the sample” for simplicity) and the sample width center C. The half of the side closer to the X-ray source F than the X-ray source F (sometimes referred to as “the left side of the sample” for simplicity) has a difference in the calculation method of the effective divergence angle. The reason is that when the X-ray incident angle θ changes, the amount of the X-ray irradiation width protruding from the sample width on the right side of the sample S is different from the amount of the X-ray irradiation width protruding from the sample width on the left side of the sample S. Because. Thus, by calculating the effective divergence angle by dividing the sample width 2A into two at the center C, more accurate intensity correction can be performed as compared with the method of calculating the effective divergence angle based on FIG. .

  FIG. 13 is a graph showing that the X-ray irradiation width defined by the diverging slit is asymmetrical between the left portion and the right portion from the sample width center. This graph plots the X-ray irradiation width formed by the X-ray passing through the diverging slit at the sample position by calculation when the goniometer radius is 185 mm and the diverging angle of the diverging slit is “1 °”. It is. A curve A1 indicates a change in the X-ray irradiation width in the right half of the sample S in FIG. Curve A2 shows the change in the X-ray irradiation width in the left half of the sample in FIG.

  As is apparent from this graph, when the X-ray source F moves to the left from the position of the X-ray incident angle θ = 90 ° in FIG. 12 and the incident angle θ gradually decreases, the X-ray irradiation width The right side spread and left side spread are asymmetric. Accordingly, when the effective divergence angle of the divergence slit is obtained by calculation based on the sample width, it is possible to calculate an accurate effective divergence angle by separately calculating the right and left sides of the sample width.

  Next, in the graph of FIG. 14, the goniometer radius R = 185 mm in FIG. 12, the actual divergence angle of the divergence slit is “1 °”, and a plurality of different sample widths 2A (specifically, 2A = 20 mm, 10 mm) , 5 mm) for each sample width, the effective divergence angle portions β1 and β2 are obtained based on the above equations (4) and (5), and the effective divergence angle β is calculated based on the equation β = β1 + β2. First, by plotting the effective divergence angle β as relative X-ray intensity (intensity ratio), the diffraction angle dependence of the diffraction line intensity with the sample width 2A as a parameter is expressed.

This graph shows the following.
(1) In a sample having a sample width of 2A = 20 mm (standard packed sample: curve A), the relative X-ray intensity (intensity ratio) is in a region where the diffraction angle is 2θ = 19.59 ° (2θ ≧ 19.59 °). The relative X-ray intensity decreases in a region where “1” and the diffraction angle 2θ is smaller than 19.59 ° (2θ <19.59 °). This means that when the sample width 2A is 20 mm, the X-ray irradiation width does not protrude from the sample width 2A in the region of 2θ ≧ 19.59 °, so the relative X-ray intensity (intensity ratio) is maintained at “1”. In the region of 2θ <19.59 °, the relative X-ray intensity (intensity ratio) of the diffraction lines decreases due to the X-ray irradiation width protruding from the sample width 2A.

(2) Relative X-ray intensity (intensity ratio) in a region where the diffraction angle is 2θ = 38.7 ° (2θ ≧ 38.7 °) in a sample having a sample width 2A = 10 mm (curve B: a sample having a small amount). Is “1”, and the relative X-ray intensity decreases in a region where the diffraction angle 2θ is smaller than 38.7 ° (2θ <38.7 °). This is because when the sample width 2A is 10 mm, the X-ray irradiation width does not protrude from the sample width 2A in the region of 2θ ≧ 38.7 °, so the relative X-ray intensity (intensity ratio) is maintained at “1”. In the region of 2θ <38.7 °, the relative X-ray intensity (intensity ratio) of the diffraction lines decreases due to the X-ray irradiation width protruding from the sample width 2A.

(3) Relative X-ray intensity (intensity ratio) in a region having a diffraction angle 2θ = 81.5 ° (2θ ≧ 81.5 °) in a sample having a sample width 2A = 5 mm (curve C: a sample having a smaller amount) ) Is “1”, and the relative X-ray intensity decreases in a region where the diffraction angle 2θ is smaller than 81.5 ° (2θ <81.5 °). This means that when the sample width 2A is 5 mm, the X-ray irradiation width does not protrude from the sample width 2A in the region of 2θ ≧ 81.5 °, so the relative X-ray intensity (intensity ratio) is maintained at “1”. In the region of 2θ <81.5 °, the relative X-ray intensity (intensity ratio) of the diffraction lines decreases due to the X-ray irradiation width protruding from the sample width 2A.

(4) As the sample width 2A becomes narrower, the diffraction angle 2θ at which the relative X-ray intensity begins to attenuate shifts to the high angle side. That is, as the sample amount decreases, the region of the diffraction angle 2θ in which the relative X-ray intensity of the diffraction line intensity changes becomes wider on the 2θ low angle side, and it becomes difficult to compare the diffraction line profile with the standard filled sample. The angular area expands on the low angle side.

(5) When a diffraction line peak is obtained in the region of the diffraction angle 2θ where the relative X-ray intensity decreases in the curves A, B and C, the diffraction line peak is in a state where the relative X-ray intensity is decreased. Since it is a peak, it cannot be said that it represents the correct intensity. In this case, the diffraction line peak can be corrected to a correct state where the relative X-ray intensity = 1 by multiplying the obtained diffraction line peak by the reciprocal of the slopes of the reduced intensity portions of the curves A, B, and C. The above equation (6) means this.

  Next, in the X-ray diffraction measurement method according to the present invention, it is desirable that the diffraction lines emitted from the sample are detected by the X-ray detection means through the light receiving slit and the monochromator. The monochromator in this case is a monochromator that selectively diffracts diffraction lines from the sample and guides them to the X-ray detection means. According to this aspect of the invention, since the background intensity in the original data before performing the intensity correction can be removed, it is possible to avoid correcting the background intensity together with the peak intensity when performing the intensity correction, Therefore, a more accurate correction result can be obtained.

Next, an X-ray diffraction apparatus according to the present invention regulates (1) an X-ray source that emits X-rays, a sample holder that supports a sample, and the divergence of X-rays emitted from the X-ray source. A diverging slit that leads to the sample, an X-ray detection unit that detects a diffraction line emitted from the sample, and an X-ray intensity calculation unit that obtains an X-ray intensity based on an output signal of the X-ray detection unit, (2) The divergence angle of the divergence slit is fixed. (3) The divergence slit is a slit that regulates the X-ray irradiation width in the sample width direction of the sample supported by the sample holder. (4) The sample The holder supports the sample in a vertically long arrangement in which the sample width is narrower than the standard sample width and the sample height is the same as the standard sample height. (5) The X-ray intensity calculating means The X-ray intensity I _obs (θ) determined based on the output of the detection means is The true X-ray intensity I _tru (θ) is obtained by correction based on the effective divergence angle calculated from the sample width.

  According to the device of the present invention, since the fixed divergence slit is used as the divergence slit, the structure can be simplified and the cost can be reduced as compared with the case where the variable divergence slit is used as the divergence slit. Further, since the measurement is performed with the sample placed in a vertically long arrangement (see FIG. 8B), even when the amount of the sample is small, a higher angle region of 2θ than in the case of the horizontally long arrangement (see FIG. 8A). In this case, a strong diffraction line can be obtained, and accurate diffraction data can be obtained in a short time.

  When the sample is placed in a vertically long arrangement, the X-ray irradiation width protrudes from the sample width not only in the low angle region of 2θ (for example, 20 ° or less) but also in the medium angle region of 2θ (for example, about 60 °), Therefore, a situation occurs in which the relative X-ray intensity (intensity ratio) of the diffraction line is different from that of the standard packed sample. Therefore, even if a qualitative analysis is performed by comparing a diffraction profile obtained by measurement with respect to a vertically arranged sample with standard data (for example, ICDD card data) obtained in advance with respect to the standard sample, accurate analysis cannot be performed. Things happen.

  In this regard, in the present invention, the X-ray intensity obtained based on the output of the X-ray detection means is corrected based on the effective divergence angle calculated from the sample width. The relative X-ray intensity can be maintained constant by compensating for the decrease in the relative X-ray intensity (intensity ratio) in the low angle region. For this reason, when a qualitative analysis is performed by comparing the diffraction profile of a sample having a narrow sample width with the standard diffraction profile of a sample having a standard sample width, an accurate analysis result can be obtained.

Next, in the X-ray diffraction apparatus according to the present invention, the X-ray intensity calculation means is as shown in FIG.
(1) When the sample width of the sample S is “2A”, the X-ray incident angle to the sample S is “θ”, and the goniometer radius is “R”, the effective divergence angle “β” is
tan β = (sin θ) / (R / 2A)
Based on
(2) When the actual divergence angle of the divergence slit 2 is “γ” and the X-ray intensity obtained based on the output of the X-ray detection means 10 is I _obs (θ), the true X-ray intensity I _tru ( θ)
I _true (θ) = (γ / β) I _obs (θ)
It is desirable to calculate based on

In the X-ray diffractometer according to the present invention, the X-ray intensity calculation means is as shown in FIG.
(1) When the sample width of the sample is “2A”, the X-ray incident angle to the sample is “θ”, and the goniometer radius is “R”, the X-ray is more effective than the sample width center C in the effective divergence angle “β”. The effective divergence angle portion “β1” on the side far from the source F and the effective divergence angle portion “β2” on the side closer to the X-ray source F than the sample width center C among the effective divergence angle “β”
tan β1 = (sin θ) / {(R / A) −cos θ}
tan β2 = (sin θ) / {(R / A) + cos θ}
Based on
(2) When the actual divergence angle of the divergence slit S is “γ” and the X-ray intensity obtained based on the output of the X-ray detection means 10 is I _obs (θ), the true X-ray intensity I _tru ( θ)
I _true (θ) = {γ / (β1 + β2)} × I _obs (θ)
It is desirable to calculate based on

  The invention mode based on FIG. 12 is a system in which the effective divergence angle in the above-described invention mode based on FIG. 11 is analyzed more precisely, so that the relative X-ray intensity (intensity ratio) can be corrected accurately. It is.

Next, in the X-ray diffraction apparatus according to the present invention, the X-ray intensity calculation means integrates the output signal of the X-ray detection means for a predetermined sampling time to obtain the X-ray intensity Iobs (θ), and further once It is desirable to obtain the true X-ray intensity Itru (θ) from the X-ray intensity Iobs (θ) at every sampling time and to store the true X-ray intensity Itru (θ). According to this inventive aspect, the true X-ray intensity I _{tru (θ)} is treated as raw data measurement result itself rather than being treated as data of the correction results. This true X-ray intensity _I.sub.tru (.theta.) Can be immediately input to the image data arithmetic circuit and displayed on the display screen or printed by a printer. The true X-ray intensity I _tru (θ) is not stored as corrected data but as raw data of measurement results in a predetermined storage area in the computer's internal storage device or external storage device.

As another method, the measured X-ray intensity I _obs (θ) is stored as it is without correction, and the measured X-ray intensity I _obs (θ) is _converted into the true X-ray intensity I _tru during the subsequent data processing. It is also possible to save after correcting to (θ).

  Next, an X-ray diffractometer according to the present invention includes a light receiving slit provided between the sample holder and the X-ray detecting means, and a monochromator provided between the light receiving slit and the X-ray detecting means. It is desirable to have more. At this time, the monochromator is a monochromator that selectively diffracts the diffraction line from the sample and guides it to the X-ray detection means. According to this aspect of the invention, since the background intensity in the original data before performing the intensity correction can be removed, it is possible to avoid correcting the background intensity together with the peak intensity when performing the intensity correction, Therefore, a more accurate correction result can be obtained.

  According to the X-ray diffraction measurement method and the X-ray diffraction apparatus according to the present invention, the fixed divergence slit is used as the divergence slit, so that the structure can be simplified and the cost can be reduced as compared with the case where the variable divergence slit is used as the divergence slit. it can. Further, since the measurement is performed with the sample placed in a vertically long arrangement (see FIG. 8B), even when the amount of the sample is small, a higher angle region of 2θ than in the case of the horizontally long arrangement (see FIG. 8A). A strong diffraction line can be obtained (for example, 80 ° or more), and accurate diffraction data can be obtained in a short time.

  When the sample is placed in a vertically long arrangement, the X-ray irradiation width protrudes from the sample width not only in the low angle region of 2θ (for example, 20 ° or less) but also in the medium angle region of 2θ (for example, about 60 °), Therefore, a situation occurs in which the relative X-ray intensity (intensity ratio) of the diffraction line is different from that of the standard packed sample. Therefore, even if a qualitative analysis is performed by comparing a diffraction profile obtained by measurement with respect to a vertically arranged sample with standard data (for example, ICDD card data) obtained in advance with respect to the standard sample, accurate analysis cannot be performed. Things happen.

  In this regard, in the present invention, the X-ray intensity obtained based on the output of the X-ray detection means is corrected based on the effective divergence angle calculated from the sample width. By compensating for the decrease in relative X-ray intensity (intensity ratio) in the low angle region, it is possible to approximate the intensity ratio characteristic of the standard packed sample, and an accurate qualitative analysis can be performed.

  Hereinafter, an X-ray diffraction measurement method and an X-ray diffraction apparatus according to the present invention will be described based on embodiments. Of course, the present invention is not limited to this embodiment. In the following description, the drawings are referred to. In the drawings, the components may be shown in different ratios from the actual ones in order to show the characteristic parts in an easy-to-understand manner.

  FIG. 1 shows an embodiment of an X-ray diffraction apparatus according to the present invention. FIG. 1 is a front view, in which the horizontal direction is the horizontal direction and the vertical direction is the vertical direction. The X-ray diffractometer 1 shown here includes an X-ray source F that generates X-rays, a divergence slit 2 that restricts divergence of X-rays, a θ-rotation table 4 that supports a sample holder 3, and a θ-rotation table 4. A 2θ turntable 5 provided coaxially and a detector arm 6 extending from the 2θ turntable 5 are provided.

  The X-ray source F is formed by a filament that generates thermoelectrons when energized, and a target disposed opposite to the filament. Specifically, the region on the outer peripheral surface of the target where the thermoelectrons collide is an X-ray focal point, and this X-ray focal point becomes the X-ray source F. The surface of the target that forms the X-ray source F is formed of, for example, Cu (copper). The X-ray source F is provided inside the X-ray tube 7 whose inside is a vacuum. X-rays emitted from the X-ray source F are extracted from the X-ray tube 7 so as to travel downward by about 6 ° with respect to the horizontal direction. The X-ray source F and the diverging slit 2 are fixed in a fixed position. A sample S is packed in a predetermined position of the sample holder 3. The divergence slit 2 regulates the divergence of the X-ray so that the X-ray generated by the X-ray source F enters the sample S.

  On the detector arm 6, a scattering slit 8, a light receiving slit 9, and an X-ray detector 10 are fixedly provided. The θ rotation mechanism 13 is connected to the θ rotation table 4. A 2θ rotation mechanism 14 is connected to the 2θ rotation table 5. The θ rotation mechanism 13 and the 2θ rotation mechanism 14 are mechanisms for rotating the θ rotation table 4 and the 2θ rotation table 5 with fine angular accuracy, respectively. For example, the servo is controlled by a power transmission system including a worm and a worm wheel. It can be set as the mechanism which transmits rotation of electric motors, such as a motor and a pulse motor, to each turntable 4 and 5. FIG.

  The scattering slit 8 prevents scattered X-rays generated by air scattering or the like other than the sample from entering the X-ray detector 10. The light receiving slit 9 is provided at a point where X-rays diffracted by the sample S are concentrated, and prevents X-rays other than the concentrated X-rays from entering the X-ray detector 10. The X-ray detector 10 is constituted by, for example, a zero-dimensional X-ray detector. A zero-dimensional X-ray detector is a detector that detects X-rays received in a predetermined region as a bundle of X-rays without determining the light receiving position, and uses, for example, an SC (Scintillation Counter). Composed. The X-ray detector 10 outputs a signal corresponding to the amount of received X-ray, and the intensity detection circuit 15 calculates the X-ray intensity based on the output signal. The intensity detection circuit 15 may be incorporated in the X-ray detector 10 in appearance.

  A zero-dimensional X-ray detector is a one-dimensional X-ray detector that detects X-rays in a linear region, such as PSPC (Position Sensitive Proportional Counter), a two-dimensional X-ray detector that detects X-rays in a planar region, For example, it means to exclude an X-ray detector using a planar X-ray phosphor, but if a one-dimensional X-ray detector or a two-dimensional X-ray detector is used as a zero-dimensional X-ray detector, one of them is used. A two-dimensional X-ray detector and a two-dimensional X-ray detector are also included in the zero-dimensional X-ray detector.

The incident angle of the X-ray R ₁ that exits from the X-ray source F and enters the sample S through the diverging slit 2 is defined as “θ”. The diffraction angle of the diffraction line R ₂ detected by the X-ray detector 10 is “2θ”. When the θ rotation table 4 is rotated by the θ rotation mechanism 13, the X-ray incident angle θ changes. This rotation of the θ turntable 4 is referred to as “θ rotation”. When the 2θ rotating table 5 is rotated by the 2θ rotating mechanism 14, the diffraction angle 2θ changes. This rotation of the 2θ turntable 5 is referred to as “2θ rotation”. The 2θ rotation of the 2θ turntable 5 is a rotation at an angular velocity twice as large as the θ rotation of the θ turntable 4.

  It should be noted that the X-ray source F and the sample S need only be relatively rotated when performing the θ rotation, and a configuration in which the sample S is fixedly arranged and the X-ray source F is rotated by θ can be employed. In this case, the 2θ rotation of the 2θ turntable 5 is opposite to the θ rotation of the X-ray source F so that the X-ray detector 10 is placed at a diffraction angle 2θ that is twice the X-ray incident angle θ. The same angular velocity is set in the direction.

A goniometer is an angle measuring mechanism constituted by each element of the θ rotation table 4, the θ rotation mechanism 13, the 2θ rotation table 5, the 2θ rotation mechanism 14, and the detector arm 6. An optical system including the goniometer and extending from the X-ray source F to the X-ray detector 10, in this embodiment, the X-ray source F, the diverging slit 2, the sample S, the scattering slit 8, the light receiving slit 9, and the X-ray detector 10. The optical system including the goniometer is an X-ray optical system. In the present embodiment, an X-ray optical system (so-called vertical type) is configured such that the surface drawn by the X-ray optical axis (that is, the center line of the X-rays R ₁ and R ₂ ) is included in the vertical plane during θ rotation and 2θ rotation. X-ray optical system) is employed, but an X-ray optical system (so-called horizontal X-ray optical system) having a configuration in which the surface thereof is included in a horizontal plane can also be employed.

  The X-ray optical system of this embodiment is a concentrated optical system. When the X-ray incident angle θ and the X-ray diffraction angle 2θ change, the X-ray source F and the light receiving slit 9 pass through the surface of the sample S and are perpendicular to the paper surface. It exists on the goniometer circle Cg centering on the ω-axis extending in the direction. Further, the three points of the X-ray source F, the sample S, and the light receiving slit 9 are on the concentrated circle Cf when the X-ray incident angle θ and the X-ray diffraction angle 2θ change.

The X-ray intensity signal I _obs (θ) output from the intensity detection circuit 15 is input to the control device 17. The control device 17 is configured by a computer including a CPU (Central Processing Unit), a memory, and the like. The θ rotation mechanism 13 and the 2θ rotation mechanism 14 are connected to the input / output unit of the control device 17. An input device 20 such as a keyboard and a mouse is connected to the input / output unit of the control device 17, and a printer 18 and a display 19 are connected as output devices.

  As shown in FIG. 2, the control device 17 includes a CPU (Central Processing Unit) 21, a ROM (Read Only Memory) 22, a RAM (Random Access Memory) 23, a memory 24, and a bus 25 for connecting these elements. The memory 24 can be formed by an appropriate storage medium, for example, a mechanical memory such as a hard disk, a CD (Compact Disk), an MO (Magneto-optic), a semiconductor memory, or the like. The CPU 21 performs calculation and control according to a program stored in the memory 24. The ROM 22 stores basic data and a basic operating system. The RAM 23 functions as a potential file for temporarily storing various data.

The θ rotation mechanism 13, 2θ rotation mechanism 14, input device 20, printer 18, display 19, and intensity detection circuit 15 shown in FIG. 1 are connected to the control device 17 via a bus 25 in FIG. In the memory 24, a file 27 storing program software for performing X-ray diffraction measurement and a file 28 for storing diffraction line intensity data I _true (θ) described later are provided.

  In FIG. 1, solar slits can be provided between the X-ray source F and the diverging slit 2 and between the scattering slit 8 and the light receiving slit 9 as necessary. By these solar slits, it is possible to limit the spread of diffraction lines in the vertical direction (Z direction) and prevent the resolution of diffraction line peaks from being lowered. Moreover, a monochromator can be provided between the light receiving slit 9 and the X-ray detector 10 as necessary. With this monochromator, unnecessary Kβ rays can be removed, and continuous X-rays and fluorescent X-rays that are harmful to the detection of minute peaks can be cut.

  As shown in FIGS. 3A to 3F, the sample holder 3 is formed by providing an opening 11 for packing a sample on a metal plate having a thickness of several millimeters, for example, an Al (aluminum) plate. . Although the opening 11 of the present embodiment is a through hole, the opening 11 may be a bottomed recess. In this embodiment, the width of the opening 11 is 20 mm (Fig. (A)), 12 mm (Fig. (B)), 8 mm (Fig. (C)), 4 mm ((Fig. (D)), 2 mm (Fig. (E)). 6 types of sample holders 3 of 1 mm ((f) (f)) are prepared, and the height of the opening 11 is 20 mm in any sample holder 3. When the sample is packed in the opening 11, the opening 11 In the following description, the opening 11 may be referred to as a “sample region”.

  The sample holder 3A in FIG. 3A is a standard sample holder used when a sufficiently large amount of sample is a measurement object, and is referred to as the volume of the opening 11 (hereinafter referred to as “area” in a plan view). Is the largest sample holder. The sample region (opening) 11 of the standard sample holder 3A is a region having an area suitable for standard data (for example, an ICDD card) generally used in the field of qualitative analysis of X-ray diffraction measurement. Each of the sample holders 3B to 3F shown in FIGS. 3B to 3F is a sample holder used for a sample with a small amount available.

  In these sample holders 3B to 3F, since the width of the opening 11 is narrower than the width of the opening 11 of the standard sample holder 3A, the amount of the sample that can be packed in these openings 11 is reduced. In actual measurement, a sample holder having an opening 11 having an optimum capacity is selected in accordance with an available sample amount. Depending on which one of the sample holders 3A to 3F is used, a difference occurs in the diffraction line intensity correction processing described later, which will be described in detail later.

  Instead of preparing the sample holders 3B to 3F (FIGS. (B) to (f)) whose sample width is narrower than the standard dimension (20 mm), only the standard sample holder 3A is prepared, When the amount is small, as shown in FIG. 4, an amorphous body (for example, a glass body) 16 having an appropriate width is attached to the left end and the right end in the opening 11 of the standard sample holder 3 </ b> A. The sample S may be packed in the narrowed region between the amorphous bodies 16.

  3 and 4, each sample holder 3 is arranged at a predetermined position in the X-ray optical system by mounting the side portion 12 on the side far from the opening 11 at a predetermined position of the θ rotation table 4 in FIG. 1. Is done. When the sample holder 3 is thus arranged at the predetermined position, the sample packed in the opening 11 is shown in FIG. 8B for the sample holders 3B to 3F other than the standard sample holder 3A (FIG. 3A). As described above, the X-ray source F is arranged vertically.

  The operation of the X-ray diffraction apparatus having the above configuration will be described below with reference to the flowchart of FIG. In this embodiment, since there are differences in processing methods between when the sample amount is large and when the sample amount is small, these will be described individually.

(Measurement when the amount of sample is large)
When the amount of the sample to be measured is sufficient, the measurer selects the sample holder 3A shown in FIG. 3A having the opening 11 of the standard sample area, and packs the sample in the opening 11. . Then, the sample holder 3A packed with the sample is attached to a predetermined location of the θ rotation table 4 of FIG. As a result, the sample S is placed on the X-ray optical path from the X-ray source F to the X-ray detector 10 as shown in FIGS. 6 (a) and 6 (b).

  Next, in steps S1 and S2 in FIG. 5, the optical axis of the X-ray optical system in FIG. 1 is adjusted as necessary. Next, in step S3, the measurement conditions stored in a predetermined area in the memory 24 of FIG. 2 are read. These measurement conditions are various conditions related to the measurement performed using the X-ray optical system of FIG. 1, and among these measurement conditions, any of the sample holders 3 of FIGS. The condition of what is used is included.

  Information on the sample holder 3 is input in advance by the measurer through the input device 20 of FIG. As an input method, an alternative selection method for selecting one of the six types of sample holders 3 is desirable. As described with reference to FIG. 4, when the sample region is narrowed using the amorphous body 16, it is desirable to indicate the sample width Ws by numerical input.

  Alternatively, a unique mark is attached to each sample holder 3 in FIGS. 3A to 3F, and a mark reading sensor is provided at an appropriate position on the θ rotation table 4 in FIG. When mounted on the turntable 4, the width of the opening 11 (that is, the sample width) in the mounted sample holder 3 can be automatically read.

  In addition, since the measurement currently considered is a case where the sample amount is sufficiently large, the measurer selects the standard sample holder 3A in FIG. 3A and packs the sample in the opening 11 thereof. Then, an instruction to select the standard sample holder 3A is given through the input device 20 of FIG.

Next, after confirming that the sample holder 3 is mounted in step S4, emission of X-rays including Cu Kα rays from the X-ray source F of FIG. 1 is started in step S5, and in FIG. 1 θ rotation of the θ rotation table 4 and 2θ rotation of the 2θ rotation table 5 are started. While each of the X-ray incident angle θ and the diffraction line detection angle 2θ increases from the initial value, Bragg diffraction conditions between the X-ray incident angle θ and the sample S
2 dsin θ = nλ
However, diffraction lines are generated from the sample S when d: lattice spacing, λ: X-ray wavelength, and n: reflection order are satisfied.

The diffracted rays are received by the X-ray detector 10 and a detection signal is output from the X-ray detector 10 at that time. This output signal is transmitted to the intensity detection circuit 15, and the intensity detection circuit 15 calculates the X-ray intensity based on the signal. The X-ray intensity signal I _obs (θ) is transmitted to the control device 17. The controller 17 integrates the X-ray intensity signals at predetermined sampling times in steps S7 and S8, and determines the accumulated X-ray intensity as the X-ray intensity I _obs (θ) of the corresponding diffraction angle 2θ (step). S9). In this specification, the diffraction line intensity I (2θ) with the diffraction angle 2θ as a variable is expressed as I (θ) with the X-ray incident angle θ as a variable for convenience of explanation.

As described above, the X-ray intensity I _obs (θ) for each diffraction angle 2θ is obtained. Note that the intensity detection circuit 15, not the control device 17, can take charge of the process of _obtaining the X-ray intensity I _obs (θ) by integrating the X-ray intensity signals for each sampling time.

  As the sampling method, a continuous sampling method can be used, or a step sampling method can be used. Continuous sampling is a method of capturing diffraction lines while updating the 2θ angle at predetermined time intervals while continuously rotating the X-ray detector 10 by 2θ. Step sampling is a method in which the X-ray detector 10 is intermittently rotated by 2θ at a predetermined time interval to acquire diffraction lines at each 2θ stop position while updating the 2θ angle. In this embodiment, any sampling method may be adopted.

  Next, in step S10, it is determined whether or not to correct the diffraction line intensity. This correction is performed when the amount of the sample is small, that is, when measurement is performed using the sample holders 3B to 3F (FIGS. 3B to 3F) other than the standard sample holder 3A of FIG. This is performed in order to compensate for a decrease in the relative X-ray intensity (intensity ratio) of the diffraction lines as shown in the diagrams B and C in FIG. The measurement considered now is when the sample amount is sufficient and the standard sample holder 3A of FIG. 3A is used, and it is confirmed in step S3 that the measurer has selected the standard sample holder 3A. Therefore, the CPU makes a “No” determination at step S10 to proceed to step S12.

The X-ray intensity I _obs (θ) measured in steps S7 to S9 is sequentially stored in a predetermined area in the RAM 23 or the memory 24 in FIG. 2 in step S12 during the measurement. In step S13, the CPU generates image data, for example, R, G, B color image data. This image data may be one-dimensional image data, two-dimensional image data, or three-dimensional image data. A “one-dimensional image” is an image that displays information by lines drawn in a plane. A “two-dimensional image” is an image that displays information by a plane drawn in a plane. A “three-dimensional image” is an image that displays information in a perspective view drawn in a plane.

  The generated image data is transmitted to the image controller in the display 19 of FIG. 2 in step S14 and displayed as an image on the screen of the display. For example, as shown in FIG. 15, a diffraction line profile A and a diffraction line profile B are displayed on the plane coordinates with the diffraction angle 2θ on the horizontal axis and the diffraction line intensity (Intensity) on the vertical axis. The graph shown in FIG. 15 is a graph of a one-dimensional image. This image display can be performed before the measurement is completed in FIG. 1, that is, before the θ rotation and 2θ rotation reach a predetermined final angle value. In this case, the diffraction line profile A or the like in FIG. Are gradually displayed from the low angle side of 2θ.

The CPU can create print data for the printer 18 based on I _obs (θ) obtained by the measurement and send the print data to the drive control circuit of the printer 18. Thereby, I _obs (θ) can be printed on paper or the like. In the case of printing, there is little need to start printing during the scan measurement of θ-2θ, so print data is generated based on the measurement result data after the θ-2θ scan measurement is completed. That is enough. When the above processing is performed to the end of the desired diffraction angle 2θ and the X-ray diffraction measurement is finished (YES in step S15), the measurement is finished.

(Measurement when sample amount is small)
When the amount of the sample to be measured is small and the entire region of the opening 11 of the standard sample holder 3A in FIG. 3A cannot be filled, the measurer has a small sample region 11 according to the sample amount. Any one of the sample holders 3B to 3F (FIGS. 3B to 3F) is selected, and the sample is packed into the opening 11 thereof. Then, the sample holder packed with the sample is attached to a predetermined portion of the θ turntable 4 in FIG. As a result, as shown in FIGS. 9A and 9B, the vertically long sample S having the sample width Ws narrower than the standard sample width Wr reaches the X-ray detector 10 from the X-ray source F. It is arranged on the X-ray optical path.

When measuring a sample with a small amount, the same steps as those for the standard packed sample are performed as steps S1 to S9 in FIG. However, before starting the measurement, the measurer selects one of the narrow sample widths from FIG. 3B to FIG. 3F as the sample holder to be used, so the CPU performs intensity correction in step S10. Judgment is made (YES in step S10). Then, the control proceeds to step S11, and the intensity I _obs (θ) output from the intensity detection circuit 15 is sampled over the course of the sampling time while the θ-2θ scanning rotation is performed in the X-ray optical system of FIG. correcting the true intensity I _{tru (θ)} by a predetermined correction process on each.

  For the sample placed in the vertically long arrangement of FIG. 8B, the relative X-ray intensity (intensity ratio) of the diffraction line from a relatively high angle side of the diffraction angle 2θ as shown in the line B or line C in FIG. Even if measurement data of diffraction lines are obtained, the data does not have versatility that can be compared with a standard packed sample obtained under a condition where the relative X-ray intensity is constant. The correction performed in step S11 in FIG. 5 is performed in order to compensate for such a decrease in relative X-ray intensity and to make the measurement data versatile.

This intensity correction will be described in detail. In FIG. 12, the sample width of the sample S is “2A”, the effective divergence angle of the divergence slit 2 calculated from the sample width 2A is “β”, and the effective divergence on the side farther from the X-ray source F than the sample width center C is. The angle portion is “β1”, the effective divergence angle portion closer to the X-ray source F than the sample width center C is “β2”, the X-ray incident angle to the sample S is “θ”, and the goniometer radius is “ R ”, the effective divergence angle portions β1 and β2 calculated from the sample width 2A are
tan β1 = (sin θ) / {(R / A) −cos θ} (4)
tan β2 = (sin θ) / {(R / A) + cos θ} (5)
The effective divergence angle β is
β = β1 + β2
It is. The CPU performs arithmetic processing of the above equations (4) and (5) to obtain effective divergence angle portions β1 and β2 for each diffraction angle 2θ.

Next, the actual divergence angle of the divergence slit 2 is “γ (gamma)”, the X-ray intensity calculated based on the output of the X-ray detector 10 is I _obs (θ), and the true X-ray intensity is I _{If true} (θ),
I _true (θ) = {γ / (β1 + β2)} × I _obs (θ) (6)
Therefore, the CPU corrects the X-ray intensity I _obs (θ) by performing the calculation process of the above equation (6) for the intensity data I _obs (θ) output from the intensity detection circuit 15 in FIG. Then, the true X-ray intensity I _tru (θ) is obtained.

  The correction using the above equation (6) is a region where the effective divergence angle β of the divergence slit 2 determined based on the sample width 2A of the sample S is smaller than the actual divergence angle γ (that is, the effective divergence angle portion β1). , Β2 is effectively used in a region where the actual divergence angle γ is smaller than half of the actual divergence angle γ.

For example, in the graph of FIG. 14, I _tr (θ) obtained in this way is the portion where the relative X-ray intensity of the diagram B (sample width 10 mm) or the diagram C (sample width 5 mm) decreases to the lower left. This corresponds to correction so that the line intensity = 1. As a result, the relative X-ray intensity of the diffraction line intensity I _tru (θ) obtained by the correction is compensated so as to maintain a correct constant value over a wide range of the diffraction angle 2θ. Therefore, this I _tru (θ) is standardized. A correct qualitative analysis can be performed by comparing with the data.

In the present embodiment, in step S11 in FIG. 5, the intensity correction formula is defined by dividing the sample width 2A into two parts on the far side and the near side from the X-ray source F as shown in FIG. Was used to correct. However, the intensity correction formula is not limited to this. For example, as shown in FIG. 11, the effective divergence angle β is obtained based on the entire sample width 2A without dividing the sample width 2A into two parts. The measurement data I _obs (θ) may be corrected based on the effective divergence angle β.

In this case, the effective divergence angle β is calculated from the sample width 2A.
tan β = (sin θ) / (R / 2A) (1)
And the true X-ray intensity I _tru (θ) is
I _true (θ) = (γ / β) I _obs (θ) (2)
Sought by.
The correction using the above equation (2) is effectively used in a region where the effective divergence angle β of the divergence slit determined based on the sample width of the sample is smaller than the actual divergence angle γ.

  As described above, according to the X-ray diffraction apparatus of the present embodiment, the diverging slit 2 calculated from the sample width of the sample S using the X-ray intensity Iobs (θ) obtained based on the output of the X-ray detector 10. Since the correction was made based on the effective divergence angle, the decrease in the relative X-ray intensity (intensity ratio) in the 2θ low-angle region with respect to the vertically arranged sample S was compensated to make the relative X-ray intensity constant. Can be maintained. For this reason, when a qualitative analysis is performed by comparing the diffraction profile of the sample S having a narrow sample width with the standard diffraction profile of the sample having the standard sample width, an accurate analysis result can be obtained.

(Other embodiments)
The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made within the scope of the invention described in the claims.
For example, the X-ray optical system shown in FIG. 1 uses a so-called vertical goniometer in which the diffraction plane, which is a plane drawn by the X-ray optical axis by θ-2θ rotation, is a vertical plane. Thus, a so-called horizontal goniometer in which the diffractive surface is a horizontal plane can be used.

  In the embodiment described above, it is considered to perform measurement using six types of sample holders 3 as shown in FIG. 3, but the types of sample holders 3 are not limited to six types. Even if there are six types, the specific value of the sample width can be changed as appropriate. Further, instead of preparing a plurality of sample holders having different sample widths, the opening width (that is, the sample width) can be changed by attaching an amorphous body to the opening of the standard sample holder.

  In the embodiment shown in FIG. 1, a monochromator, a so-called counter monochromator (not shown) can be additionally provided between the light receiving slit 9 and the X-ray detector 10. This monochromator can be formed of, for example, graphite. This monochromator selectively diffracts the diffraction lines from the sample S and guides them to the X-ray detector 10, and prevents other unnecessary X-rays from being taken into the X-ray detector 19. By providing this counter monochromator, the following effects can be obtained.

  According to the slit correction of this embodiment, the effect that the diffraction line intensity ratio can be measured correctly can be obtained. However, simultaneously with the effect, the background intensity tends to increase in proportion to the correction coefficient of the peak intensity. This is caused by interference from scattered X-rays scattered from places other than the sample on the sample plate. However, if the background of the original data is lowered by using a counter monochromator, the corrected data can be used. The background increase can be reduced.

  The counter monochromator itself can be of a conventionally known structure, and therefore detailed illustration is omitted. For example, a monochromator disclosed in Japanese Patent Laid-Open No. 6-109668 is used. Can do.

The inventor obtains the diffraction line intensity I _obs (θ) using an X-ray optical system having a goniometer radius R = 150 mm, an actual divergence angle of the divergence slit of 1.25 °, and a sample width 2A of 20 mm. An experiment was performed to correct the diffraction line intensity and obtain the diffraction line intensity I _tru (θ). As a result, the result shown in the data output of FIG. 15 was obtained. In this data output, the diffraction line profile B is a profile in which the intensity is not corrected. The diffraction line profile A is a profile after intensity correction.

  According to the calculation based on FIG. 12, relative X-rays are measured in the region of 2θ <20.08 ° when measuring the goniometer radius R = 150 mm, the actual divergence angle of the divergence slit is 1.25 °, and the sample width 2A is 20 mm. This is a calculation result that strength (strength ratio) decreases.

  In the result of FIG. 15, in the region where the diffraction angle 2θ is larger than about 20 °, the profile A and the profile B substantially coincide and overlap. In the region where the diffraction angle 2θ is smaller than about 20 °, the intensity value after correction is larger than the intensity value before correction. The fact that the corrected intensity value A is larger than the uncorrected intensity value B means that the relative X-ray intensity (intensity ratio) of diffraction lines is constant in the low angle region where 2θ is about 20 ° according to the present invention. This indicates that the value has been corrected to the correct value.

It is a figure which shows one Embodiment of the X-ray-diffraction apparatus which implements the X-ray-diffraction measuring method which concerns on this invention. It is a block diagram which shows the electrical control system of FIG. 1 in detail. It is a top view which shows the example of the sample holder used with the X-ray optical system shown in FIG. It is a top view which shows the other example of the sample holder used with the X-ray optical system shown in FIG. It is a flowchart which shows the flow of control performed by the apparatus of FIG. It is a figure which shows the example of a measurement using a standard sample holder. It is a figure which shows the state of a different measurement timing in the same measurement example as FIG. It is a figure which shows two examples regarding the method of arrangement | positioning for few samples. It is a figure which shows one Embodiment of the X-ray-diffraction measuring method which concerns on this invention. It is a figure which shows the state of a different measurement timing in the same measuring method as FIG. It is a figure which shows the conditions at the time of calculating | requiring the effective divergence angle of a divergence slit based on the sample width of a sample. It is a figure which shows the other conditions at the time of calculating | requiring the effective divergence angle of a divergence slit based on the sample width of a sample. It is a graph which shows the left-right asymmetry of X-ray irradiation width. It is a graph which shows the diffraction angle dependence of diffraction line intensity. It is a data output which shows the result of the experiment using this invention method.

Explanation of symbols

1. 1. X-ray diffractometer, 2. Diverging slit, Sample holder, 4. θ turntable,
5. 2θ turntable; 6. a detector arm; X-ray tube, 8. Scattering slit,
9. Receiving slit, 10. X-ray detector, 11. Opening, 13. θ rotation mechanism,
14.2θ rotation mechanism, Amorphous body, 17. Control device, 20. Input device,
24. Memory, 25. Bus, C.I. Sample width center, Cg. Goniometer circle,
Cf. Concentrated circle, F. X-ray source (X-ray focal point), Hr. Standard sample height,
Hs. Narrow sample height; Goniometer radius, R1. Incident X-rays, R2. Diffraction lines,
S. Sample, W0. X-ray irradiation width, Wr. Standard sample width, Ws. Narrow sample width,
θ. X-ray incident angle, 2θ. Diffraction angle, ω. Axis

Claims (9)

In an X-ray diffraction measurement method in which X-rays radiated from an X-ray source are regulated by a diverging slit and irradiated on a sample, and a diffraction line emitted from the sample is detected by an X-ray detection means.
The divergence angle of the divergence slit is a fixed value,
The divergent slit is a slit that regulates the X-ray irradiation width in the sample width direction,
The sample is arranged in a vertically long arrangement in which the sample width is narrower than the standard sample width and the sample height is the same as the standard sample height,
An X-ray diffraction measurement method, wherein an X-ray intensity obtained based on an output of the X-ray detection means is corrected based on an effective divergence angle calculated from a sample width. The X-ray diffraction measurement method according to claim 1,
When the sample width of the sample is “2A”, the X-ray incident angle to the sample is “θ”, and the goniometer radius is “R”, the effective divergence angle “β”
tan β = (sin θ) / (R / 2A)
Based on
Wherein the actual divergence angle of the divergence slit and "γ", when the X-ray intensity calculated based on the output of the X-ray detector was set to I _{obs (theta),} true X-ray intensity I _tru the _(theta) ,
I _true (θ) = (γ / β) I _obs (θ)
X-ray diffraction measurement method characterized in that it is obtained based on The X-ray diffraction measurement method according to claim 1,
When the sample width of the sample is “2A”, the X-ray incident angle to the sample is “θ”, and the goniometer radius is “R”, the effective divergence angle “β” is farther from the X-ray source than the sample width center. Side effective divergence angle portion “β1” and effective divergence angle portion “β2” of the effective divergence angle “β” closer to the X-ray source than the center of the sample width,
tan β1 = (sin θ) / {(R / A) −cos θ}
tan β2 = (sin θ) / {(R / A) + cos θ}
Based on
Wherein the actual divergence angle of the divergence slit and "γ", when the X-ray intensity calculated based on the output of the X-ray detector was set to I _{obs (theta),} true X-ray intensity I _tru the _(theta) ,
I _true (θ) = {γ / (β1 + β2)} × I _obs (θ)
X-ray diffraction measurement method characterized in that it is obtained based on   4. The X-ray diffraction measurement method according to claim 1, wherein a diffraction line emitted from the sample is detected by the X-ray detection unit through a light receiving slit and a monochromator, and the monochromator is An X-ray diffraction measurement method comprising selectively diffracting a diffraction line from a sample and introducing the diffraction line to the X-ray detection means. An X-ray source emitting X-rays;
A sample holder for supporting the sample;
A divergence slit that regulates the divergence of X-rays emitted from the X-ray source and guides it to the sample;
X-ray detection means for detecting diffraction lines emitted from the sample;
X-ray intensity calculation means for obtaining X-ray intensity based on an output signal of the X-ray detection means,
The divergence angle of the divergence slit is fixed,
The divergent slit is a slit that regulates the X-ray irradiation width in the sample width direction of the sample supported by the sample holder,
The sample holder supports the sample in a vertically long arrangement in which the sample width is narrower than the standard sample width and the sample height is the same as the standard sample height,
The X-ray intensity calculation means corrects the X-ray intensity I _obs (θ) obtained based on the output of the X-ray detection means based on the effective divergence angle calculated from the sample width of the sample, thereby obtaining a true X An X-ray diffraction apparatus characterized by _{obtaining a} line intensity I _true (θ). The X-ray diffraction apparatus according to claim 5,
The X-ray intensity calculation means
When the sample width of the sample is “2A”, the X-ray incident angle to the sample is “θ”, and the goniometer radius is “R”, the effective divergence angle “β” is
tan β = (sin θ) / (R / 2A)
Based on
Wherein the actual divergence angle of the divergence slit and "γ", when the X-ray intensity calculated based on the output of the X-ray detector was set to I _{obs (theta),} true X-ray intensity I _tru the _(theta) ,
I _true (θ) = (γ / β) I _obs (θ)
An X-ray diffractometer that calculates based on the above. The X-ray diffraction apparatus according to claim 5,
The X-ray intensity calculation means
When the sample width of the sample is “2A”, the X-ray incident angle to the sample is “θ”, and the goniometer radius is “R”, the effective divergence angle “β” is farther from the X-ray source than the sample width center. Side effective divergence angle portion “β1” and effective divergence angle portion “β2” of the effective divergence angle “β” closer to the X-ray source than the center of the sample width,
tan β1 = (sin θ) / {(R / A) −cos θ}
tan β2 = (sin θ) / {(R / A) + cos θ}
Based on
When the divergence angle of the divergence slit is “γ” and the X-ray intensity calculated based on the output of the X-ray detection means is I _obs (θ), the true X-ray intensity I _tru (θ) is
I _true (θ) = {γ / (β1 + β2)} × I _obs (θ)
An X-ray diffractometer that calculates based on the above.   8. The X-ray diffraction apparatus according to claim 5, wherein the X-ray intensity calculation unit integrates an output signal of the X-ray detection unit with a predetermined sampling time to obtain an X-ray intensity Iobs ( θ), and the true X-ray intensity Itru (θ) is obtained from the X-ray intensity Iobs (θ) at every sampling time, and the true X-ray intensity Itru (θ) is stored. X-ray diffractometer.   The X-ray diffractometer according to any one of claims 5 to 8, wherein a light receiving slit provided between the sample holder and the X-ray detecting means, the light receiving slit and the X-ray detecting means X-ray diffraction, wherein the monochromator is a monochromator that selectively diffracts diffraction lines from the sample and guides them to the X-ray detection means apparatus.

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