Fluorescence X-ray analysis device

Abstract

In the fluorescence X-ray analysis apparatus of the present invention, the quantitative mechanism, under automatic setting, restricts the overlap correction coefficient to a negative value. When the standard sample does not contain any components that can excite the analytical line, the absorption excitation correction coefficients of all correction components are restricted to positive values. The theoretical intensity of the fluorescence X-rays that should be generated by multiple samples with assumed compositions is calculated. Based on the theoretical intensity, the theoretical matrix correction coefficient is calculated. The values ​​of each theoretical matrix correction coefficient are set as the upper limit of the absorption excitation correction coefficient for positive values ​​and the lower limit of the absorption excitation correction coefficient for negative values, in order to perform multiple regression calculations.

Description

[0001] Related Application

[0002] This application claims priority from Japanese Patent Application No. 2023-027360 filed on February 24, 2023, the entire contents of which are incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to a fluorescent X-ray analysis device in which primary X-rays are irradiated to a sample, and the content of a component in the sample is calculated by a quantitative mechanism of a calibration curve method for performing absorption excitation correction and overlap correction or a fundamental parameter method including overlap correction, based on a measured intensity of generated fluorescent X-rays. BACKGROUND

[0004] Conventionally, fluorescent X-ray analysis devices that perform quantitative analysis are roughly classified into a type based on a calibration curve method and a type based on a fundamental parameter method (also referred to as an FP method). In the quantitative analysis based on the calibration curve method, in order to analyze an unknown sample, a set of standard samples whose component contents (also referred to as concentration ratios) are known are used, and a calibration curve is calculated by the correlation between the component contents and the measured intensity of the fluorescent X-rays (measurement line) of the measurement element corresponding to the component. In addition, the component refers to an element or a compound. Furthermore, when the component is an element, the element itself is the measurement element corresponding to the component; when the component is a compound, the element that represents the compound is the measurement element corresponding to the component (for example, see paragraph 0002 of Patent Literature 1).

[0005] In the quantitative analysis based on the calibration curve method, in addition to background correction related to the background, absorption excitation correction (also referred to as matrix correction) related to absorption excitation caused by coexisting elements, and overlap correction related to the overlap of interference lines are performed (for example, regarding absorption excitation correction, see paragraph 0003 of Patent Literature 1). Thereby, absorption excitation correction coefficients, overlap correction coefficients are calculated by multiple regression calculation based on the measured intensity of the standard sample and the known component content together with the calibration curve constant at the time of making the calibration curve expressed by, for example, the following formula (1), so that the accuracy of the calibration curve is good (for example, regarding the accuracy, see paragraphs 0006 to 0014 of Patent Literature 1).

[0006] W i = (AI i 3 + BI i 2 + CI i + D) (1 + ∑ j M ij I j ) + ∑ j O ij Ij …(1) W i : content

[0007] I: measured intensity

[0008] A, B, C, D: calibration curve constants

[0009] i: analysis component

[0010] j: absorption excitation correction component or overlap correction component

[0011] M ij : absorption excitation correction coefficient of j component to i component

[0012] O ij : overlap correction coefficient of j component to i component

[0013] On the other hand, in the quantitative analysis based on the FP method, the theoretical intensity of the fluorescent X-rays generated from each component in the sample is calculated based on the assumed content of each component, and the assumed content of each component is gradually approximated and corrected in a manner so as to coincide with the converted measured intensity after the conversion of the measured intensity determined by the detection mechanism into the theoretical intensity scale, and thus the content of the components in the sample is calculated. Here, in order to perform the analysis of an unknown sample, a set of standard samples whose component contents are known is required, and the device sensitivity curve is obtained based on the correlation between the theoretical intensity calculated based on the known content and the measured intensity (for example, see paragraph 0003 and FIG. 4 of Patent Literature 2, and paragraph 0009 of Patent Literature 1).

[0014] In the quantitative analysis based on the FP method, absorption excitation correction is performed for all components in principle, and in addition, overlap correction is performed in the device sensitivity curve represented by the following formula (2) as needed depending on the components (for absorption excitation correction, see, for example, paragraphs 0069 to 0074 of Patent Literature 2). Thus, the overlap correction coefficient is calculated based on the measured intensity of the standard sample and the theoretical intensity of the known component content together with the device sensitivity constant by multiple regression calculation at the time of making the device sensitivity curve, so that the accuracy of the device sensitivity curve is good.

[0015] I Ti = aI i 3 + bI i 2 + cI i + d + ∑ j O ij I j …(2) I T : theoretical intensity

[0016] I: measured intensity

[0017] a, b, c, d: device sensitivity constant

[0018] i: analysis component

[0019] j: overlap correction component

[0020] o ij : overlap correction coefficient of j component to i component

[0021] [Related Art Documents]

[0022] [Patent Documents]

[0023] Patent Document 1: Japanese Patent Application Publication No. 2021-51053

[0024] Patent Document 2: International Publication No. 2018 / 168939

[0025] Patent Document 3: Japanese Patent Application Publication No. 2000-36765 SUMMARY

[0026] [Problems to be Solved by the Invention]

[0027] However, in order to make the accuracy of the calibration curve or the device sensitivity curve good, if the correction coefficient is calculated by multiple regression calculation without particularly setting a limit, for example, in a case where sample handling is not proper in a standard sample, an overlap correction coefficient (positive overlap correction coefficient) that is physically impossible, in which the overlap intensity of the interference line becomes negative, can be calculated. Using such a calibration curve or device sensitivity curve, it is clear that correct analysis cannot be performed.

[0028] The present application is made in view of the above-described related art problems, and aims to provide a fluorescent X-ray analysis device in which the content of a component in a sample is calculated by a quantitative mechanism of a calibration curve method for performing absorption excitation correction and overlap correction or a fundamental parameter method including overlap correction, whereby when a correction coefficient is calculated by multiple regression calculation, a physically impossible correction coefficient can be prevented from being calculated.

[0029] [Means for Solving the Problems]

[0030] To achieve the above object, the first aspect of the present application is a fluorescent X-ray analysis device in which, first, primary X-rays are irradiated to a sample, and the content of a component in the sample is calculated by a quantitative mechanism using a calibration curve method for performing absorption excitation correction and overlap correction, based on the measured intensity of the generated fluorescent X-rays. Further, in the case of manual setting when calculating calibration curve constants, absorption excitation correction coefficients, and overlap correction coefficients by multiple regression calculation based on the measured intensity of a standard sample and the content of a known component, it is possible to select whether to limit the overlap correction coefficients to negative values, and to select whether to limit the absorption excitation correction coefficients of all correction components to positive values, to perform the multiple regression calculation.

[0031] On the other hand, in the case of automatic setting, the quantitative mechanism limits the overlap correction coefficients to negative values, limits the absorption excitation correction coefficients of all correction components to positive values when the standard sample does not contain a component capable of exciting an analysis line, and calculates the theoretical intensity of the fluorescent X-rays that should be generated from a plurality of samples composed of hypothetical components, based on the theoretical intensity, calculates theoretical matrix correction coefficients by calculation, sets a prescribed multiple of each of the theoretical matrix correction coefficients to a value, sets the upper limit value of the absorption excitation correction coefficient for a positive value, and sets the lower limit value of the absorption excitation correction coefficient for a negative value, to perform the multiple regression calculation.

[0032] According to the fluorescent X-ray analysis device of the first aspect, the quantitative mechanism calculates the correction coefficients by multiple regression calculation with appropriate setting of limits, whereby it is possible to prevent the calculation of physically impossible correction coefficients.

[0033] The second aspect of the present application is a fluorescent X-ray analysis device in which, first, primary X-rays are irradiated to a sample, and the content of a component in the sample is calculated by a quantitative mechanism using a basic parameter method including overlap correction, based on the measured intensity of the generated fluorescent X-rays. Further, in the case of manual setting when calculating device sensitivity constants and overlap correction coefficients by multiple regression calculation based on the measured intensity of a standard sample and the content of a known component, it is possible to select whether to limit the overlap correction coefficients to negative values, to perform the multiple regression calculation, and in the case of automatic setting, the overlap correction coefficients are limited to negative values, to perform the multiple regression calculation.

[0034] According to the fluorescent X-ray analysis device of the second aspect, the quantitative mechanism also calculates the correction coefficients by multiple regression calculation with appropriate setting of limits, whereby it is possible to prevent the calculation of physically impossible correction coefficients.

[0035] The present application also encompasses any combination of at least two of the features disclosed in the claims and / or the description and / or the drawings. In particular, the present application encompasses any combination of more than two of the claims. BRIEF DESCRIPTION OF DRAWINGS

[0036] The application will be understood more clearly by reference to the following description of preferred embodiments shown in the attached drawings. However, the embodiments and drawings are for illustration and explanation only and should not be used to limit the scope of the application. The scope of the application is defined by the claims. In the drawings, like parts are designated by like reference numbers throughout the several views.

[0037] Figure 1 is a schematic diagram of a fluorescent X-ray analysis device according to an embodiment of the present application. DETAILED DESCRIPTION

[0038] Hereinafter, a fluorescent X-ray analysis device according to an embodiment of the present application will be described. As shown in Figure 1 the drawing, the fluorescent X-ray analysis device according to the present embodiment is a scanning-type fluorescent X-ray analysis device that measures the intensity of secondary X-rays 5 generated by irradiating a sample 1, 14 (both unknown samples 1 and standard samples 14) with primary X-rays 3, and includes a sample stage 2 for placing the sample 1, 14; an X-ray source 4 such as an X-ray tube for irradiating the sample 1, 14 with the primary X-rays 3; a spectrometric element 6 for spectrometrically analyzing the fluorescent X-rays or the like emitted from the sample 1, 14; and a detector 8 for receiving the secondary X-rays 7 spectrometrically analyzed by the spectrometric element 6 and detecting the intensity thereof. The output of the detector 8 is input to a control mechanism 11 such as a computer for controlling the entire device, via an amplifier, a wave height analyzer, a counting mechanism, or the like, not shown in the drawing.

[0039] The fluorescence X-ray analysis device of the embodiment is a wavelength dispersion type and a scanning type, and has a linkage mechanism 10 that links the spectrometric element 6 and the detector 8, i.e., a so-called goniometer, in order to change the wavelength of the secondary X-rays 7 incident on the detector 8. When the secondary X-rays 5 are incident on the spectrometric element 6 at an incident angle θ, an extension line 9 of the secondary X-rays 5 forms a spectrometric angle 2θ that is twice the incident angle θ with the spectrometric (diffracted) secondary X-rays 7, and the linkage mechanism 10 rotates the spectrometric element 6 about an axis O that passes through the center of the surface of the spectrometric element 6 and is perpendicular to the paper, and rotates the detector 8 about the axis O by twice the rotation angle of the spectrometric element 6, in order to change the wavelength of the spectrometric secondary X-rays 7 while the spectrometric secondary X-rays 7 are incident on the detector 8. The value of the spectrometric angle 2θ (2θ angle) is input to the control mechanism 11 from the linkage mechanism 10. In addition, in the present application, the fluorescence X-ray analysis device can be a wavelength dispersion type and a multi-element simultaneous analysis type, or can be an energy dispersion type.

[0040] In the fluorescence X-ray analysis device of the embodiment, as a program mounted on the control mechanism 11, there is a quantification mechanism 13 that calculates the content of each component in the sample 1, 14 based on the measured intensity of the fluorescence X-rays 5 by using a calibration curve method that performs absorption excitation correction and overlap correction. The quantification mechanism 13 calculates, for example, the calibration curve constants A, B, C, D, the absorption excitation correction coefficient M ij and the overlap correction coefficient O ij in the above formula (1) based on the measured intensity and the known content of the components of the standard sample 14 by multiple regression calculation, and in the case of manual setting, it is possible to select whether to limit the overlap correction coefficient O ij to a negative value, and it is possible to select whether to limit the absorption excitation correction coefficient M ij of all the correction components j to a positive value to perform multiple regression calculation.

[0041] In the case of manual setting, for example, the display 15, such as a liquid crystal display, connected to the control mechanism 11 displays the content of "Allow positive overlap correction" together with a check box, and if the operator checks the check box using an input mechanism, such as a mouse, not shown, it indicates that the selection is to not limit the overlap correction coefficient O ij to a negative value, but in the default state in which the check box is not checked, it indicates that the selection is to limit the overlap correction coefficient O ij to a negative value.

[0042] In addition, the display 15 displays the content of "Allow absorption correction only" together with a check box, and if the operator checks the check box using the input mechanism, it indicates that the selection is to limit the absorption excitation correction coefficient M ijis limited to a positive value, but, in the default state where the check box is not checked, indicates that selection of no such limitation and permission of excitation correction. Also, the quantification mechanism 13 performs multiple regression calculation according to the limitation corresponding to these selections. By checking the check box, it is possible to select not to set the overlap correction coefficient O ij is limited to a negative value, and it is possible to select to set the absorption / excitation correction coefficient M ij is limited to a positive value because, in the existing users of the fluorescent X-ray analysis device, there are cases where such analysis is also required.

[0043] On the other hand, the quantification mechanism 13, in the case of automatic setting, sets the overlap correction coefficient O ij is limited to a negative value, and in the case where the standard sample 14 does not contain a component capable of exciting the analysis line, sets the absorption / excitation correction coefficient M ij is limited to a positive value, and calculates theoretical intensities of fluorescent X-rays that should be generated from a plurality of samples having assumed compositions, obtains theoretical matrix correction coefficients by calculation based on the theoretical intensities, and sets a value of a prescribed multiple, for example, 10 times, of each of the theoretical matrix correction coefficients to an upper limit value of the absorption / excitation correction coefficient M ij for a positive value, and a lower limit value of the absorption / excitation correction coefficient M ij for a negative value, to perform multiple regression calculation.

[0044] For example, on the display 15, the content of "automatically set upper and lower limit values of variables" is displayed together with the check box, and if the operator checks the check box by using the input mechanism, it becomes automatic setting, and the quantification mechanism 13 sets the overlap correction coefficient O ij to a negative value.

[0045] As for the absorption / excitation correction coefficient M ij , the quantification mechanism 13 first refers to a library file stored in advance in which absorption / excitation of elements with respect to each other is associated, and sets all of the correction components j to a positive value if the standard sample 14 does not contain a component capable of exciting the analysis line. Also, as in the known semi-empirical parameter method, theoretical intensities of fluorescent X-rays that should be generated from a plurality of samples having assumed compositions are calculated, and theoretical matrix correction coefficients are obtained by calculation based on the theoretical intensities. Furthermore, a value of a prescribed multiple, for example, 10 times, of each of the theoretical matrix correction coefficients is set to an upper limit value of the absorption / excitation correction coefficient M ij for a positive value, and a lower limit value of the absorption / excitation correction coefficient M ij for a negative value, to perform multiple regression calculation.

[0046] The fluorescent X-ray analysis device according to the present embodiment, the quantification mechanism 13 appropriately sets the limitation, and obtains the overlap correction coefficient O ij and the absorption / excitation correction coefficient M ijThus, it is possible to prevent the calculation of physically impossible correction coefficients, such as an overlap correction coefficient in which the overlap intensity of an interference line is negative (a positive overlap correction coefficient), or an absorption excitation correction coefficient that generates an analysis line that should not be excited.

[0047] The quantification mechanism 13 of the fluorescence X-ray analysis device of the present embodiment can calculate the contents of the components in the sample 1, 14 using a basic parameter method including overlap correction. In this case, the quantification mechanism 13 calculates the device sensitivity constants a, b, c, d in the above equation (2), for example, and the overlap correction coefficient o ij In the case of manual setting, whether or not to limit the overlap correction coefficient o ij to a negative value is selected.

[0048] In the case of manual setting, for example, the content "Allow positive overlap correction" is displayed on the display 15 together with a check box, and if the operator checks the check box using an input mechanism such as a mouse that is not shown, it indicates that the overlap correction coefficient o ij is selected to be limited to a negative value; but in the default state in which the check box is not checked, it indicates that the overlap correction coefficient o ij is selected to be limited to a negative value.

[0049] On the other hand, in the case of automatic setting, the quantification mechanism 13 limits the overlap correction coefficient to a negative value and performs multiple regression calculation. For example, the content "Automatically set variable upper and lower limit values" is displayed on the display 15 together with a check box, and if the operator checks the check box using an input mechanism, it becomes automatic setting, and the quantification mechanism 13 limits the overlap correction coefficient o ij to a negative value and performs multiple regression calculation.

[0050] According to the fluorescence X-ray analysis device of the present embodiment in which the quantification mechanism 13 uses a basic parameter method including overlap correction, the quantification mechanism 13 appropriately sets the limit to calculate the overlap correction coefficient o ij Thus, it is possible to prevent the calculation of physically impossible correction coefficients, such as an overlap correction coefficient in which the overlap intensity of an interference line is negative (a positive overlap correction coefficient), or an absorption excitation correction coefficient that generates an analysis line that should not be excited.

[0051] As described above, a preferred embodiment has been described with reference to the accompanying drawings, but various changes and modifications can be easily conceived by those skilled in the art from the present specification. Therefore, such changes and modifications should be interpreted as still falling within the scope of the present invention defined by the claims.

[0052] [Explanation of symbols]

[0053] 1, 14: sample

[0054] 3: primary x-ray

[0055] 5: fluorescent x-ray

[0056] 13: quantifying mechanism

[0057] 15: display

Claims

1. A fluorescent X-ray analysis device in which primary X-rays are irradiated to a sample, and the content of a component in the sample is calculated by a quantitative mechanism of a calibration curve method for performing absorption excitation correction and overlap correction, based on the measured intensity of the generated fluorescent X-rays, wherein the quantitative mechanism performs the following operations: when a calibration curve constant, an absorption excitation correction coefficient, and an overlap correction coefficient are calculated by multiple regression calculation based on the measured intensity of a standard sample and the content of a known component, in the case of manual setting, whether or not the overlap correction coefficient is limited to a negative value, and whether or not the absorption excitation correction coefficient of all correction components is limited to a positive value, are selectable, and multiple regression calculation is performed, in the case of automatic setting, the overlap correction coefficient is limited to a negative value, the absorption excitation correction coefficient of all correction components is limited to a positive value when the standard sample does not contain a component capable of exciting an analysis line, and the theoretical intensity of the fluorescent X-rays that should be generated from a plurality of samples composed of assumed components is calculated, based on the theoretical intensity, a theoretical matrix correction coefficient is calculated by calculation, a value of a prescribed multiple of each theoretical matrix correction coefficient is calculated, a positive value is set as an upper limit value of the absorption excitation correction coefficient, and a negative value is set as a lower limit value of the absorption excitation correction coefficient, and multiple regression calculation is performed.

2. A fluorescent X-ray analysis device in which primary X-rays are irradiated to a sample, and the content of a component in the sample is calculated by a quantitative mechanism of a fundamental parameter method including overlap correction, based on the measured intensity of the generated fluorescent X-rays, wherein the quantitative mechanism performs the following operations: when a device sensitivity constant and an overlap correction coefficient are calculated by multiple regression calculation based on the measured intensity of a standard sample and the content of a known component, in the case of manual setting, whether or not the overlap correction coefficient is limited to a negative value is selectable, and multiple regression calculation is performed, in the case of automatic setting, the overlap correction coefficient is limited to a negative value, and multiple regression calculation is performed. ​ ​ ​ ​ ​ ​ ​ ​

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