Data correction method

Abstract

To provide a method for correcting X-ray diffraction data that suppresses peak broadening and asymmetry.SOLUTION: A data correction method comprises steps of: constructing, from a two-dimensional detection image acquired by an X-ray analytical apparatus, an ideal two-dimensional image from which the influence of divergence is excluded; and correcting the two-dimensional detection image acquired by the X-ray analytical apparatus on the basis of intensity information of the ideal two-dimensional image. Thus, the two-dimensional detection image acquired by the X-ray analytical apparatus can be corrected on the basis of the intensity information of the ideal two-dimensional image.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for correcting data. [Background technology]

[0002] Patent Document 1 discloses an X-ray device that can suppress the influence of the umbrella effect and obtain highly reliable X-ray measurement results by rotating a monochromator and an X-ray inspection device in a direction perpendicular to the 2θ rotation direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-035409 Summary of the Invention [Problem to be solved by the invention]

[0004] In X-ray diffraction (XRD), increasing the slit width increases the X-ray intensity and enables measurements to be completed in a shorter time. However, this increases the peak broadening and asymmetry, resulting in a decrease in measurement resolution.

[0005] The present disclosure provides a method for correcting X-ray diffraction data that suppresses peak broadening and asymmetry even when the slit width is widened in X-ray diffraction. [Means for solving the problem]

[0006] The data correction method according to the present disclosure comprises the steps of constructing an ideal two-dimensional image from a two-dimensional detection image acquired by an X-ray analysis device, excluding the effects of divergence, and correcting the two-dimensional detection image acquired by the X-ray analysis device based on intensity information of the ideal two-dimensional image. This allows the two-dimensional detected image acquired by the X-ray analysis device to be corrected based on intensity information of an ideal two-dimensional image. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a method for correcting X-ray diffraction data that suppresses peak broadening and asymmetry. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a procedure for correcting an X-ray diffraction image according to the present disclosure. [Figure 2] 10A to 10C are diagrams showing detailed content of a detailed procedure for correcting a two-dimensional image according to the present disclosure. [Figure 3] FIG. 2 is a diagram illustrating the detailed principle of data correction according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 Hereinafter, an X-ray diffraction correction method according to this embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing an example of the procedure of the method for correcting X-ray diffraction data. In the following, the correction method will be described as being executed by a correction device 1. Typically, a computer can be used as the correction device 1.

[0010] As shown in FIG. 1, the correction device 1 constructs an ideal two-dimensional image that eliminates the influence of divergence based on a two-dimensional detection image acquired by an X-ray analysis device (step S11), and corrects the two-dimensional detection image acquired by the X-ray analysis device based on intensity information of the constructed ideal two-dimensional image (step S12).

[0011] 1, before step S11, the correction device 1 cuts out a thin section near the central axis of the two-dimensional detection image acquired by the X-ray diffraction device, integrates this region in the distance (=θ) direction, and calculates information to be used in step S11 (step S10). As a result, the correction device 1 creates one-dimensional integrated data. In this case, in step S11, an ideal two-dimensional image that excludes the influence of divergence is constructed based on the one-dimensional integrated data (one-dimensional image) constructed in step S10 by cutting out a thin section near the central axis of the two-dimensional detection image and integrating this region in the θ direction.

[0012] Each step will be explained in detail below. Figure 2(a) is a diagram showing how a two-dimensional image is obtained using an X-ray diffraction device, and Figures 2(b) to 2(d) are supplementary diagrams that provide detailed information about the procedure for correcting a blurred two-dimensional image obtained using the configuration shown in Figure 2(a).

[0013] Figure 2(a) shows an example of a configuration for irradiating a sample with X-rays and acquiring a 2D detected image. The 2D detected image can be acquired by passing X-rays irradiated from an X-ray irradiation unit (not shown) through a slit plate with a vertical slit of a specified width, and then projecting the X-rays that have passed through the sample to be measured onto a detector. In an X-ray diffraction instrument, increasing the width of the slit in the slit plate increases the X-ray intensity. However, this results in a lateral shift in the positions where Debye rings appear from the left and right sides of the slit, resulting in a horizontally blurred 2D detected image. In other words, the overlapping of Debye rings causes peak broadening and asymmetry (umbrella effect) in the 2D detected image.

[0014] First, the detailed procedure of step S10 will be described with reference to FIGS. 1, 2(a), 2(b) and 2(c).

[0015] As shown in FIG. 2(b), the correction device 1 cuts out a thin area near the central axis from the two-dimensional detection image, which is an area less affected by blur, and creates one-dimensional integrated data by integrating this area in the θ direction (the horizontal direction in the two-dimensional detection image in FIG. 2(b)) based on the distance from the X-ray irradiation point (step S10-1). Here, the width of blur in the horizontal direction of the two-dimensional detection image is assumed to be u [px]. In addition, in the one-dimensional integrated data, the horizontal axis represents the distance from the X-ray irradiation point, and the vertical axis represents the intensity. For example, the point a in the two-dimensional detection image corresponds to the peak point indicated by a in the integrated data. The same applies to b and c.

[0016] As shown in Figure 2(a), the distance from the X-ray irradiation point to the pixel of interest can be calculated using Pythagoras' theorem. In other words, if the distance from the sample to the detector is L [m] and the distance between the center of the X-ray on the detector and the pixel of interest is x [m], then the distance from the X-ray irradiation point to the pixel of interest is:

number

[0017] The correction device 1 creates a function for calculating the intensity from the distance from the pixel of interest calculated in S10-1 based on the one-dimensional integral data (step S10-2). For example, in the case of Python, Scipy.interpolate can be used.

[0018] Here, in order for the correction device 1 to perform data correction, information outside the range of the original data is also required. Therefore, the correction device 1 creates an array enlarged by half the blur width (u [px]) (step S10-3). That is, as shown in FIG. 2(c), if the vertical length of the detected image is a [px] and the horizontal length is b [px], the correction device 1 creates an array with a vertical length of a [px], the same as that of the detected image, but with a horizontal length of b + u [px], which is enlarged in the left and right directions by u / 2 [px].

[0019] As in step S10-1, the correction device 1 calculates the distance between each pixel in the created array and the X-ray irradiation point using Pythagorean theorem.

[0020] Next, step S11 will be described. Fig. 2(d) shows the flow of the correction device 1 generating an ideal two-dimensional image (ideal two-dimensional image) from one-dimensional integral data.

[0021] More specifically, the correction device 1 converts the distance data included in each element of the array created in step S10-3 into intensity using the function created in step S10-2, allowing the correction device 1 to generate an ideal two-dimensional image without the umbrella effect based on the one-dimensional integral data.

[0022] Next, step S12 will be described. Fig. 2(e) shows the flow in which the correction device 1 reconstructs the intensity data of the original two-dimensional image based on the intensity data of the ideal two-dimensional image generated in step S11, thereby removing the influence of the umbrella effect.

[0023] Here, FIGS. 3(a) to 3(d) are diagrams showing the detailed principle of data correction when the correction device 1 performs data correction.

[0024] First, in Figures 3(a) to 3(d), each square represents one pixel, and the numerical value represents the intensity (number of X-ray counts) of each pixel. In other words, the numerical value increases by integrating the intensity of the blurred Debye rings. For example, if the base of the peak (e.g., intensity 1) and the peak top (e.g., intensity 10) are integrated due to the blur, the integrated intensity becomes 1 + 10 = 11.

[0025] Consider ideal data as shown in Figure 3(a). Here, assume that there is a deviation of 1px to the left and right due to the influence of the slit width of the slit provided in the slit plate in the X-ray diffraction device. Here, the correction device 1 can create measurement data that combines the ideal data, left deviation data, and right deviation data, as shown in Figure 3(b).

[0026] Here, we consider the origin of the intensity of each pixel. As shown in Figure 3(b), in an image combining ideal data and left and right blur data, for example, the pixel in the third row from the bottom and fourth column from the left (hereafter referred to as the pixel of interest), which is the area surrounded by double lines, has an integrated value of 2 for the three pieces of data, including the blur data, at the same position.

[0027] In this case, the blur data is the ideal data translated horizontally, so the "0", "1", and "1" of the right blur data, ideal data, and left blur data for the pixel of interest are equal to the "0", "1", and "1" of the area obtained by extending left and right from the pixel of interest, which is the third row from the bottom and fourth column from the left, in the ideal data shown in Figure 3(c).

[0028] In other words, in the ideal data shown in Figure 3(c), the third row from the bottom and third column from the left to the left of the pixel of interest is "0", the pixel of interest is "1", and the third row from the bottom and fifth column from the left to the right of the pixel of interest is "1", which is equal to the element of the pixel of interest in the combined measurement data shown in Figure 3(b).

[0029] Therefore, as shown in Figure 3(d), if the ideal data and blur width are known, the correction device 1 can remove the effects of blur by distributing the value of each pixel of the measured data according to the intensity ratio of the ideal data.

[0030] In other words, the correction device 1 can restore data from which the effects of blurring have been removed by performing the same process on all pixels. However, restoration is not possible for the left and right ends of the data because some of the information from the distribution source is missing.

[0031] In this way, X-ray diffraction data can be corrected to suppress peak broadening and asymmetry, and therefore, even if the slit width is widened to some extent to increase the X-ray intensity and shorten the measurement time, a decrease in measurement resolution can be suppressed.

[0032] The present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the spirit of the present invention. In other words, the above description has been omitted or simplified as appropriate for the sake of clarity, and a person skilled in the art can easily modify, add, or convert each element of the embodiment within the scope of the present invention.

Claims

1. constructing an ideal two-dimensional image from the two-dimensional detected image acquired by the X-ray analysis device, eliminating the influence of divergence; and correcting the two-dimensional detected image acquired by the X-ray analysis device based on intensity information of the ideal two-dimensional image. Data correction method.

2. The method further comprises a step of extracting a thin portion of the two-dimensional detection image acquired by the X-ray diffraction device near the central axis thereof, and integrating the extracted portion in the distance (= θ) direction to form one-dimensional integral data; the step of constructing the ideal two-dimensional image is performed using the one-dimensional integral data constructed from the two-dimensional detected image acquired by the X-ray analysis device. The data correction method according to claim 1 .

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