Correction apparatus, correction method, and correction program

Abstract

To provide a correction apparatus, correction method and correction program capable of reducing time and labor, reducing an artificiality, and improving reproducibility of correction by correcting a shift of a profile with an automatically estimated correction amount.SOLUTION: A correction apparatus 400 for correcting the profile of X-ray powder diffraction comprises a reference profile setting unit 420 for setting a reference profile, an estimation method setting unit 430 for setting an estimation method for estimating a correction amount related to the height of a sample, a correction amount estimation unit 440 for estimating the correction amount based on the estimation method, and a correction unit 460 for correcting a subject profile based on the correction amount. The correction amount is a value for maximizing the degree of coincidence between the corrected subject profile and the reference profile.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a correction device, a correction method, and a correction program for correcting an X-ray powder diffraction profile. [Background technology]

[0002] In X-ray diffraction measurements of powder samples, the powder sample is filled into the recess of a sample holder. The work of filling the sample is difficult to achieve reproducibility even for the same operator. Reproducibility also varies depending on the operator's level of skill. If the position of the sample surface during filling differs from the top surface of the sample holder, which is the reference position, the angular position of the measured profile will shift from the original angular position (see Patent Document 1).

[0003] Examples of analyses that are sensitive to peak positions include qualitative analysis and machine learning. In qualitative analysis, if a peak shift occurs in the measured profile, the degree of agreement between the peak positions in the measured profile and those recorded in the database decreases, resulting in a problem of not being able to obtain correct qualitative results. In machine learning, highly accurate information must be input as training data. Therefore, if a measured profile in which a peak shift has occurred is used as input data, correct learning cannot be performed and the inference results may be incorrect.

[0004] Component decomposition is sometimes used as a pre-processing step for qualitative analysis and machine learning. Component decomposition is an algorithm that decomposes a measured profile into profiles of different factors (see Patent Document 2), and the decomposed profile can be used for qualitative analysis and machine learning. It is known that when component analysis is performed using multiple peak-shifted profiles, the accuracy of the component analysis decreases. In that case, a problem occurs in which the peak positions of the decomposed profile are shifted from the positions originally expected, and the results of the qualitative analysis and machine learning may be erroneous. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Re-tabled publication No. 2015-119056 [Patent Document 2] JP 2019-087042 A Summary of the Invention [Problem to be solved by the invention]

[0006] To deal with the above-mentioned deviation of the sample surface, a method of directly adjusting the sample to a reference position may be adopted. For example, a machine such as a machine press can be used to prepare a uniform sample to be tested, but such physical adjustments can be difficult in some cases, and are not necessarily sufficient as a countermeasure.

[0007] It is also conceivable that the user may visually correct the deviation of the sample position on the software in response to the shift in the measured profile. Figure 12 shows a dialog box used when correcting the sample position. For example, in the specifications shown in Figure 12, when the value is changed with the slider bar or text box in the operation area 910, the corrected profile is displayed on the viewer.

[0008] When a correction amount D for the height of the sample surface is applied to an X-ray diffraction device with a goniometer radius R, the corrected diffraction angle 2θcorr is expressed as in formula (1). When the deviation of the sample position is corrected by software during analysis, the correction is equivalent to replacing the angle 2θ with the angle 2θcorr.

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[0009] However, in recent years, there are more and more opportunities to perform qualitative and quantitative analysis using machine learning, and it is necessary to process a large amount of data as training data. When processing a large amount of data, the above-mentioned method is time-consuming. In addition, if user operation is assumed, the analysis will be performed based on artificial results, and objectivity will be lost. Since the correction depends on the user's skill, there may be a problem of insufficient reproducibility.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a correction device, a correction method, and a correction program that can correct profile shifts with an automatically estimated correction amount, without requiring much effort, reducing artificiality, and improving the reproducibility of the correction. [Means for solving the problem]

[0011] (1) In order to achieve the above-mentioned object, a correction device of the present invention is a correction device that corrects an X-ray powder diffraction profile, and includes a reference profile setting unit that sets a reference profile, an estimation method setting unit that sets an estimation method for estimating a correction amount related to a sample height, a correction amount estimation unit that estimates the correction amount based on the estimation method, and a correction unit that corrects a test profile based on the correction amount, wherein the correction amount is a value that maximizes the degree of match between the corrected test profile and the reference profile.

[0012] (2) Furthermore, the correction device described in (1) above further includes a provisional correction unit that corrects the test profile with a provisional correction amount, and the correction amount estimation unit calculates the correction amount by repeatedly evaluating the degree of match between the test profile corrected based on the provisional correction amount and the reference profile.

[0013] (3) In the correction device according to (1) or (2) above, the reference profile setting unit sets the reference profile based on a profile designated by a user.

[0014] (4) In the correction device according to any one of (1) to (3) above, the reference profile setting unit sets the reference profile calculated based on a plurality of profiles.

[0015] (5) In the correction device according to any one of (1) to (4) above, the estimation method setting unit sets the least squares method or the peak top method as the estimation method.

[0016] (6) In the correction device described in any one of (1) to (5) above, the estimation method setting unit is characterized in that it sets a 2θ angle range in which the degree of agreement is maximized based on a user specification.

[0017] (7) Furthermore, in the correction device described in any one of (1) to (6) above, the correction device is characterized in that it further comprises a display unit that displays the provisional correction amount or a profile obtained by correcting the test profile based on the correction amount.

[0018] (8) Furthermore, in the correction device described in any one of (1) to (7) above, when converting the angle 2θ of the test profile into the corrected angle 2θcorr, the following formula (1) is used based on the goniometer radius R and the correction amount D related to the sample height.

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[0019] (9) Furthermore, in the correction device described in any one of (1) to (8) above, a subject for qualitative analysis is generated by correcting the test profile based on the correction amount.

[0020] (10) Furthermore, in the correction device described in any one of (1) to (9) above, a component decomposition target is generated by correcting the test profile based on the correction amount.

[0021] (11) Also, a correction method of the present invention is a correction method for correcting an X-ray powder diffraction profile, comprising the steps of: setting a reference profile; setting an estimation method for estimating a correction amount related to a sample height; estimating the correction amount based on the estimation method; and correcting a test profile based on the correction amount, wherein the correction amount is a value that maximizes the degree of match between the corrected test profile and the reference profile.

[0022] (12) Also, a correction program of the present invention is a correction program for correcting an X-ray powder diffraction profile, which causes a computer to execute a process of setting a reference profile, a process of setting an estimation method for estimating a correction amount related to a sample height, a process of estimating the correction amount based on the estimation method, and a process of correcting a test profile based on the correction amount, wherein the correction amount is a value that maximizes the degree of match between the corrected test profile and the reference profile. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of an X-ray diffraction measurement system. [Diagram 2] FIG. 2 is a block diagram showing an example of the configuration of a control device and a correction device. [Diagram 3] FIG. 13 is a block diagram showing a modified example of the configuration of the control device and the correction device. [Figure 4] FIG. 13 is a block diagram showing a modified example of the configuration of the control device and the correction device. [Diagram 5] 10 is a flowchart showing an example of the operation of the correction device. [Figure 6] FIG. 13 is a diagram illustrating an example of a UI used when preparing for estimation of a correction amount. [Figure 7] FIG. 13 is a diagram showing an example of a UI used when setting multiple reference profiles. [Figure 8]1A and 1B are diagrams showing nonnegative matrix factorization and nonnegative matrix factorization in the case where known information is included, respectively. [Figure 9] 13A and 13B are diagrams showing profiles decomposed into components when there is and is not a shift in the peak position, respectively. [Figure 10] 13(a) and (b) show uncorrected and corrected profiles and database peak positions, respectively. [Figure 11] 13A and 13B are tables showing the composition of the mixture sample when there is a height shift in the profile position and when there is no height shift, respectively. [Figure 12] FIG. 13 is a diagram showing a dialog box used when correcting the sample position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Next, an embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are used to refer to the same components in each drawing, and duplicated description will be omitted.

[0025] [X-ray diffraction measurement system] Fig. 1 is a schematic diagram showing an example of the configuration of an X-ray diffraction measurement system 100. The X-ray diffraction measurement system 100 includes an X-ray diffraction device 200 and a control device 300. The X-ray diffraction device 200 configures an optical system that irradiates X-rays on a sample and detects diffracted X-rays generated from the sample, and the optical system includes a goniometer. Note that the configuration shown in Fig. 1 is just an example, and various other configurations can be adopted.

[0026] The control device 300 is connected to the X-ray diffraction device 200, and controls the X-ray diffraction device 200 and processes and stores acquired data. The control device 300 includes a correction device 400 as a function, and the correction device 400 corrects a profile measured by X-ray powder diffraction. The control device 300 is a device equipped with a CPU and memory, and may be a PC terminal or a server on the cloud. In addition to the entire device, some devices or some functions within the device may be provided on the cloud. The input device 510 is, for example, a keyboard or a mouse, and accepts selections and designations by the user and inputs them to the control device 300 and the correction device 400. The display device 520 is, for example, a display, and displays a measured profile and a UI for estimating correction values.

[0027] By using such an X-ray diffraction measurement system 100, it is possible to measure an X-ray powder diffraction profile and correct the measured profile. In addition, it is possible to perform component decomposition using the corrected profile and perform qualitative and quantitative analysis.

[0028] In the method of the present invention, a measured profile is acquired and corrected independently of the X-ray diffraction apparatus 200 and the control device 300. Fig. 2 is a block diagram showing an example of the configuration of the control device and the correction device. Fig. 3 is a block diagram showing a modified example of the configuration of the control device and the correction device. Fig. 4 is a block diagram showing a modified example of the configuration of the control device and the correction device.

[0029] As shown in Fig. 2, the correction device 400 may be configured as a part of the functions included in the control device 300, or as shown in Fig. 3, the correction device 400 may be configured as a device different from the control device 300. Also, as shown in Fig. 4, the correction device 400 and the control device 300 may be configured as an integrated device.

[0030] [X-ray diffraction equipment] The X-ray diffraction apparatus 200 includes an X-ray generation unit 210 that generates X-rays from an X-ray focus, i.e., an X-ray source, an incident side optical unit 220, a goniometer 230, a sample stage 240 on which a sample is placed, an exit side optical unit 250, and a detector 260 that detects X-rays. The X-ray generation unit 210, the incident side optical unit 220, the goniometer 230, the sample stage 240, the exit side optical unit 250, and the detector 260 that configure the X-ray diffraction apparatus 200 may be general components, and therefore a description thereof will be omitted.

[0031] [Control device and correction device] [Control device] The control device 300 is configured by a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and memories connected to a bus. The control device 300 is connected to the X-ray diffraction device 200 and receives information from the X-ray diffraction device 200.

[0032] The control device 300 includes a control unit 310, a device information storage unit 320, a measurement data storage unit 330, and a display unit (on the control device side) 340. Each unit can transmit and receive information via a control bus L. The input device 510 and the display device 520 are connected to the CPU via an appropriate interface.

[0033] The control unit 310 controls the operation of the X-ray diffraction apparatus 200. The apparatus information storage unit 320 stores apparatus information acquired from the X-ray diffraction apparatus 200. The apparatus information includes information on the X-ray diffraction apparatus 200, such as the name of the apparatus, the type of radiation source, the wavelength, and the background. In addition, the type and composition of the constituent elements of the sample may be included.

[0034] The measurement data storage unit 330 stores the measurement profile acquired from the X-ray diffraction device 200. The measurement profile may also include the type of radiation source, wavelength, background, types of constituent elements of the sample, composition, etc. The display unit 340 displays the measurement profile on the display device 520. This allows the user to check the measurement profile. The user can also give instructions and designations to the control device 300, correction device 400, etc. based on the measurement data.

[0035] The correction device 400 corrects an X-ray powder diffraction profile. The correction device 400 includes a measurement profile acquisition unit 410, a reference profile setting unit 420, a test profile setting unit 425, an estimation method setting unit 430, a provisional correction unit 435, a correction amount estimation unit 440, a (correction device side) display unit 450, and a correction unit 460.

[0036] The measurement profile acquisition unit 410 acquires a profile to be used for correction from among the measurement profiles acquired and stored from the X-ray diffraction device 200. It is preferable to acquire not only the test profile to be corrected but also data that can be a reference profile. The reference profile is a profile used as a reference for approximating the test profile to be corrected, and a measurement profile in which the height of the sample surface coincides with the reference position may be used, or an average profile of multiple measurement profiles may be used. Even for a sample that does not contain a crystalline phase with a known angular position, a reference profile can be obtained by the method using the above measurement profile.

[0037] The reference profile setting unit 420 sets a reference profile. It is preferable that the reference profile setting unit 420 sets the reference profile based on a profile designated by the user. This makes it possible to set a reference profile even when there is little known information, thereby enabling correction. Note that if a reference profile has been designated in advance, it may be set according to that.

[0038] It is preferable that the reference profile setting unit 420 sets the reference profile using a plurality of profiles. By setting the reference profile based on a plurality of profiles in this manner, variance can be eliminated, and furthermore, a non-arbitrary reference profile can be created.

[0039] The test profile setting unit 425 sets the test profile based on the user's selection. At this time, it is preferable to correct the test profile using the received correction amount and display it on the viewer.

[0040] The estimation method setting unit 430 sets an estimation method for estimating the correction amount related to the sample height. It is preferable that the estimation method setting unit 430 sets the least square method or the peak top method as the estimation optimization method. This allows for an appropriate estimation of the correction amount. A method using a correlation coefficient may be adopted as the estimation optimization method. The estimation method setting unit 430 can also set the maximum and minimum values ​​of the correction amount and the range of the diffraction angle used for estimation based on the user's specification or selection.

[0041] The peak top method is a method for minimizing the difference between the reference profile and the test profile for the diffraction angle position of the main peak. Among the peak top methods, the method for minimizing the difference between the reference profile and the test profile for the diffraction angle position of the peak where the intensity is maximum is called the maximum intensity method.

[0042] When a method that requires repeated trials, such as the least squares method or a method using a correlation coefficient, is selected as an estimation method, the provisional correction unit 435 corrects the test profile with a provisional correction amount. If the previous correction amount is known, a value dispersed based on the previous correction amount can be used as the provisional correction amount. Alternatively, a plausible value may be calculated using another method, and the provisional correction amount may be set using the calculated value as a reference value. Note that when a method that can estimate the correction amount with one calculation, such as the peak top method, is selected, the provisional correction unit 435 does not operate. The "provisional correction amount" refers to the trial amount during repeated processing, and is different from the "correction amount." The "correction amount" refers to the estimated amount finally determined by the method of the present invention.

[0043] The correction amount estimation unit 440 estimates the correction amount based on the estimation method. The correction amount calculated using the set estimation method maximizes the degree of match between the corrected test profile and the reference profile. For example, when the least squares method is selected as the estimation method, the correction amount is calculated by repeatedly evaluating the degree of match between the test profile corrected based on the provisional correction amount and the reference profile, using the set correction amount as a provisional correction amount. When the peak top method is selected as the estimation method, the correction amount estimation unit 440 calculates the correction amount so that the difference between the peak position of the test profile and the peak position of the reference profile is minimized. This makes it possible to correct the deviation of the height position of the sample based on the estimated correction amount. As a result, it is possible to make correction with reduced artificiality without much effort, and further improve the reproducibility of the correction. In this way, the value at which the degree of match between the corrected test profile and the reference profile is maximized is treated as the correction amount.

[0044] Here, the degree of agreement between two profiles is maximum when the value relating to the difference between the two profiles is expressed by an evaluation function, and the evaluation function is maximum or minimum. The evaluation function may be any index that indicates the difference, such as the mean absolute error, the mean square error, or the mean square error, or an index that indicates the degree of agreement, such as a correlation coefficient. In the case of the peak top method, the degree of agreement is maximum when the peak positions are in agreement.

[0045] It is preferable that the correction amount estimation unit 440 estimates the correction amount in a set 2θ angle range. This allows, for example, one peak top of a certain crystal phase to be used as a reference, so that deviations in the height position of the sample can be accurately corrected for a measurement profile containing multiple crystal phases at various weight fractions.

[0046] The display unit 450 displays a profile obtained by correcting the test profile based on the provisional correction amount or the estimated correction amount, thereby allowing the user to execute the correction while checking the correction of the test profile.

[0047] The correction unit 460 corrects the test profile based on the correction amount. At this time, the correction amount is a value that maximizes the degree of match between the corrected test profile and the reference profile. The correction amount is determined according to the set estimation method. When the test profile is corrected with a tentative correction amount and the above-mentioned evaluation of the degree of match is repeated, the profile corrected with the tentative correction amount may be stored, and the corresponding profile may be read out when the correction amount is determined.

[0048] The provisional correction unit 435 and the correction unit 460 can convert the angle 2θ of the profile to be measured into a corrected angle 2θcorr using the following formula (1) based on the goniometer radius R and the correction amount D related to the sample height.

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[0049] [Correction method] Next, a description will be given of a correction method using the above-mentioned correction device 400. Fig. 5 is a flowchart showing an example of the operation of the correction device 400. First, a measurement profile to be used for correction is obtained from the measurement data acquired by X-ray diffraction measurement and stored (step S1).

[0050] The user's selection is accepted and a reference profile is set (step S2). A reference profile may be generated based on a plurality of measurement profiles and the reference profile may be set. If a reference profile has been specified in advance, the reference profile may be set according to the specification. When the reference profile is set, it is preferable that the reference profile is displayed in the viewer.

[0051] Then, the selection and designation of the user is accepted, and a test profile and a correction amount are set (step S3). At this time, it is preferable that the selected test profile is corrected with the designated correction amount and displayed on the viewer.

[0052] The user's selection is accepted and a correction amount estimation method is set (step S4). For example, the least squares method or peak top method (including maximum intensity method) can be set as the optimization method. The correction amount is estimated using the set correction amount estimation method (step S5). For example, when the least squares method is selected, a repeat process is performed so that a provisional correction profile obtained by correcting a test profile with a provisional correction amount approaches a reference profile, and an estimated correction amount is calculated.

[0053] That is, when the least squares method is specified, the least squares method is performed by changing the amount of correction to reduce the residual between the reference profile and the test profile. When the maximum intensity method is specified, the amount of correction is estimated so that the maximum intensity position of the reference profile coincides with the maximum intensity position of the test profile. When the peak top method is selected, the amount of correction when the peak positions coincide is calculated. Then, the test profile is corrected with the estimated amount of correction (step S6), and the process ends.

[0054] [User Interface] A user interface used when correcting a profile will now be described. Fig. 6 is a diagram showing an example of a UI used when preparing to estimate a correction amount. In the dialog box shown in Fig. 6, a previous correction amount 602, a current correction amount 603, and a check box 610 are displayed for a profile name 601. In Fig. 6, the provisionally corrected test profile is displayed in the viewer.

[0055] By leaving the display of the previous correction amount 602 as the previous amount, it is possible to recognize how much correction has been made based on the sample height at the time of measurement as reference information. Check box 610 is a UI that accepts the user's selection of whether or not to use it as a reference profile. The measurement profile selected by the user is used to set the reference profile. A similar check box may also be used when setting a test profile. A measurement profile that was not selected as a reference profile may also be set as a test profile. In either case, it is preferable that the test profile is displayed in a special way that is easy to understand. For example, it is possible to display the profile by changing the color of the row and highlighting it.

[0056] Note that the above description does not prevent one measurement profile from being set as both the reference profile and the test profile. For example, if all measurement profiles are set as both the reference profile and the test profile, the average profile of all measurement profiles becomes the reference profile. Then, correction based on the reference profile is performed on all measurement profiles. In this method, the user does not need to explicitly specify the reference profile and the test profile.

[0057] In the estimation setting area, the estimation method can be selected from the least squares method and the peak top method using radio buttons. Also, the range of diffraction angles to which the estimation method is applied can be specified. Pressing the estimation start button 620 moves to the algorithm for estimating the correction amount.

[0058] 7 is a diagram showing an example of a UI used when setting multiple reference profiles. Multiple profiles can be selected as the reference profile, and when multiple profiles are selected, for example, a profile obtained by combining the selected profiles can be set as the reference profile. In that case, an average profile of the selected profiles can be used as the reference profile.

[0059] [Application to qualitative and quantitative analysis] The measurement profile of X-ray powder diffraction can be corrected to perform qualitative and quantitative analysis. It is preferable to generate a corrected profile by correcting the test profile based on the correction amount calculated by the present invention as the subject of the qualitative analysis. This makes it possible to perform qualitative analysis based on the corrected profile and accurately identify the substance. In addition, the corrected profile can be used to perform quantitative analysis by Rietveld analysis or the like.

[0060] (Component decomposition) When a measurement profile is formed by overlapping profiles of multiple substances and backgrounds, it is preferable to perform component decomposition on the measurement profile. Component decomposition is the process of decomposing the measurement profile of X-ray powder diffraction into a weighted sum of multiple profiles (including the background profile). This decomposed profile is called a basis profile. Since each profile and its weight are non-negative, non-negative matrix factorization is suitable for expressing the measurement profile of X-ray powder diffraction as a weighted sum of multiple profiles. In addition, qualitative and quantitative analysis can be performed using the basis profiles.

[0061] FIG. 8(a) is a conceptual diagram showing non-negative matrix factorization. The left side of FIG. 8(a) shows a matrix in which n measurement profiles of X-ray powder diffraction having m measurement points are arranged. The right side of FIG. 8(a) shows the result of non-negative matrix factorization of this. However, the wavy equal in FIG. 8 includes not only strict agreement but also cases where the degree of discrepancy indicating the degree of closeness between the left side and the right side is equal to or less than a predetermined value. It is preferable to use known information as a constraint and perform non-negative matrix factorization of the measurement profile of X-ray powder diffraction so that the constraint is satisfied.

[0062] Fig. 8(b) is a conceptual diagram showing the state of non-negative matrix factorization when known information is included. When known information is included in the right-hand side of Fig. 8(a), the known information can be extracted and expressed as, for example, the second term on the right-hand side of Fig. 8(b). The known information is set to one or more of the matrix W with n rows and r columns, the matrix W' with n rows and s columns, and the matrix B' with s rows and m columns on the right side of Fig. 8(b). Under these constraints, W', W, and the matrix B with r rows and m columns can be optimized.

[0063] In such component decomposition, it is important that the peak position of the measurement profile is accurate. In the present invention, it is preferable to generate a target for component decomposition by correcting the test profile based on the calculated correction amount. This enables accurate component decomposition.

[0064] (Effect of peak position shift) 9(a) and (b) are diagrams showing profiles decomposed into components when there is and is not a shift in peak position, respectively. When a profile with a shift in the angular position of the peak is decomposed, a peak that should belong to one profile will belong to multiple profiles, as shown in Fig. 9(a). On the other hand, when a profile with no shift in the angular position of the peak is decomposed, the peaks of each material will belong to the profile they should belong to, as shown in Fig. 9(b).

[0065] (Machine Learning) In the qualitative analysis using machine learning, the entire profile is used as input data, and the contained crystal phase is used as output data to train a neural network. Then, the measured profile is input to the neural network, and the contained crystal phase is inferred. The height correction of the present invention can be used both during learning and inference.

[0066] During learning, a high-quality profile is required as training data. When simulation data is used as training data, a profile without height deviation can be created, and the height correction of the present invention is not used. On the other hand, when measurement data is used as training data, it is preferable to correct the height deviation of the measurement data before using it as training data.

[0067] In addition, the measurement profile is used as input data during inference, so it is preferable to correct the height deviation of the measurement profile before inputting the measurement profile to the neural network.

[0068] Although the above describes qualitative analysis using machine learning, machine learning can also be used for quantitative analysis and calculation of lattice constants. In qualitative analysis, the output data is the crystalline phase contained in the sample, while in quantitative analysis, the output data is the quantitative value of the crystalline phase contained, and in calculation of the lattice constant, the output data is the lattice constant. In either case, the handling of the profile, which is the input data, is the same as in qualitative analysis.

[0069] [Simulation 1] Based on the above correction method, the profiles without and with correction were compared with the peak positions in the database. First, a measurement profile was created when X-ray diffraction was measured on a powder sample containing a mixture of anatase, calcite, and rutile. Then, a measurement profile was created when the height of the sample surface was shifted by 100 μm from the reference position.

[0070] The prepared measurement profile was displayed on a graph together with the peak positions of the database without correction. On the other hand, the prepared measurement profile was corrected by the above correction method, and the corrected profile was displayed on a graph together with the peak positions of the database. Figures 10(a) and (b) show the uncorrected and corrected profiles and the peak positions of the database, respectively.

[0071] In each figure, the peak position in the database is indicated by a bar. The peak position in the uncorrected profile is shifted from the bar position. However, the peak position in the corrected profile is consistent with the bar position. This result shows that if the height of the sample surface is shifted by 100 μm from the reference position, an incorrect card may be selected as a candidate during qualitative analysis.

[0072] [Simulation 2] When the measurement profiles of multiple powder samples containing the same type of crystal phase but different content rates are decomposed into components, a single-phase profile of the contained crystal phase is ideally obtained. In Simulation 2, the effect of the deviation in the height of the sample surface on the accuracy of component decomposition was simulated using the following procedure.

[0073] First, 21 profiles were created in which the three crystal phases of anatase, calcite, and rutile were mixed in various weight ratios. Next, profiles with shifted sample heights were prepared for the 21 profiles. The specific height shift amount was set so that the height shift of the i-th data was 100-10*iμm (i=0,1,...,20). Finally, component decomposition was performed for the 21 profiles with height shift and the 21 profiles without height shift, respectively, to examine whether a single-phase profile of anatase could be extracted.

[0074] Figures 11(a) and (b) are tables showing the composition of the mixture sample when there is a height shift in the profile position and when there is no height shift, respectively. base_profile_2_pm100um is a profile extracted from data with a height shift. base_profile_2 is a profile extracted from data with a height shift. The main phase in Base_profile_2 is Anatase, but the weight fraction with a height shift is 75.46%, whereas the weight fraction without a height shift is 88.2. In this way, the weight fraction with a height shift is significantly different from the weight fraction without a height shift. This is because peaks other than Anatase are assigned to Base_profile_2. In this way, when there is a shift in the height of the sample surface, the accuracy of component resolution decreases, so correcting the height of the sample surface is effective.

[0075] When the profile is decomposed into components without correcting the height of the sample surface, peaks from other crystal phases may be added to a specific base profile. In that case, when the base profile is used for qualitative analysis, the number of crystal phase candidates increases, and inaccurate values ​​are calculated for the weight fraction of each crystal phase. The simulation results show that when the base profile is used for quantification, the quantitative value becomes inaccurate for profiles that have peaks from different crystal phases. [Explanation of symbols]

[0076] 100 X-ray diffraction measurement system 200 X-ray Diffraction Instrument 210 X-ray Generator 220 Incident optical unit 230 Goniometer 240 Sample stage 250 Output optical unit 260 Detector 300 Control device 310 Control section 320 Device information storage unit 330 Measurement data storage unit 340 Display unit (control device side) 400 Correction Device 410 Measurement profile acquisition unit 420 Reference Profile Setting Section 425 Test profile setting section 430 Estimation method setting unit 435 Provisional Correction Section 440 Correction amount estimator 450 Display section (correction device side) 460 Correction Unit 510 Input Device 520 Display device 601 Profile Name 602 Previous correction amount 603 This correction amount 610 Checkbox 620 Estimation start button 910 Operation area

Claims

1. A correction device for correcting an X-ray powder diffraction profile, comprising: a reference profile setting unit that sets a reference profile; an estimation method setting unit that sets an estimation method for estimating a correction amount related to the sample height; a correction amount estimation unit that estimates the correction amount based on the estimation method; a correction unit that corrects the test profile based on the correction amount, A correction device, wherein the correction amount is a value that maximizes the degree of match between the corrected test profile and the reference profile.

2. a provisional correction unit that corrects the test profile with a provisional correction amount; 2. The correction device according to claim 1, wherein the correction amount estimation unit calculates the correction amount by repeatedly evaluating the degree of coincidence between the test profile corrected based on the provisional correction amount and the reference profile.

3. 3. The correction apparatus according to claim 1, wherein the reference profile setting unit sets the reference profile based on a profile designated by a user.

4. 3. The correction apparatus according to claim 1, wherein the reference profile setting unit sets the reference profile calculated based on a plurality of profiles.

5. 3. The correction device according to claim 1, wherein the estimation method setting unit sets the least squares method or the peak-top method as the estimation method.

6. 3. The correction device according to claim 1, wherein the estimation method setting unit sets a 2θ angle range in which the degree of coincidence is maximized based on a user specification.

7. 3. The correction device according to claim 1, further comprising a display unit that displays the provisional correction amount or a profile obtained by correcting the test profile based on the correction amount.

8. A correction device as described in claim 2, further comprising a display unit that displays a profile obtained by correcting the test profile based on the provisional correction amount.

9. 3. The correction device according to claim 1, wherein the angle 2θ of the profile to be measured is converted into the corrected angle 2θcorr by using the following formula (1) based on the goniometer radius R and the correction amount D related to the sample height: [Equation 1]

10. 3. The correction device according to claim 1, wherein the subject of qualitative analysis is generated by correcting the test profile based on the correction amount.

11. 3. The correction device according to claim 1, wherein the target of component decomposition is generated by correcting the test profile based on the correction amount.

12. A correction method for correcting an X-ray powder diffraction profile, comprising: establishing a reference profile; setting an estimation method for estimating a correction amount related to the sample height; estimating the correction amount based on the estimation method; correcting the test profile based on the correction amount; A correction method, wherein the correction amount is a value that maximizes the degree of match between the corrected test profile and the reference profile.

13. A correction program for correcting an X-ray powder diffraction profile, a process of setting a reference profile; A process of setting an estimation method for estimating a correction amount related to the sample height; a process of estimating the correction amount based on the estimation method; and correcting the test profile based on the correction amount. A correction program, wherein the correction amount is a value that maximizes the degree of match between the corrected test profile and the reference profile.

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