Fluorescent x-ray analysis method, analysis program, and fluorescent x-ray analysis device

Abstract

In the present invention, the respective measured intensities of Compton and Rayleigh scattering lines (MC, MR) are extracted from the spectrum of a target sample in which a resin-containing thin film is formed on a base material (S21, S22) and a measured scattering intensity ratio (MC / R), which is the ratio of the measured intensity of the Rayleigh scattering line to the measured intensity of the Compton scattering line is obtained (S3). The thickness of the thin film and the contained amounts of respective elements constituting the target sample are determined by the fundamental parameter method on the basis of the measured scattering intensity ratio of the target sample (S5-S11).

Description

X-ray fluorescence analysis method, analysis program, and X-ray fluorescence analysis device

[0001] The present disclosure relates to an X-ray fluorescence analysis method, an analysis program, and an X-ray fluorescence analysis apparatus.

[0002] X-ray fluorescence analysis is an analytical method in which a sample is irradiated with X-rays and the fluorescent X-rays emitted from the sample are measured to analyze the constituent elements of the sample. One known analytical method using X-ray fluorescence analysis is the fundamental parameter method (hereinafter referred to as the "FP method").

[0003] The FP method is a technique for determining the content of elements in a sample by comparing theoretical intensities calculated using various physical constants with actual intensities obtained by measuring the sample. Methods for calculating theoretical intensities have been established and are disclosed in Patent Document 1, Non-Patent Document 1, etc.

[0004] Patent Document 1 discloses a method for obtaining quantitative values ​​of target elements by the FP method, taking into consideration correction for the shape of the sample, in view of the fact that the measurement intensity of fluorescent X-rays is insufficient due to the shape of the sample, etc. The method disclosed in Patent Document 1 obtains the deposition amount by utilizing the fact that the ratio of fluorescent X-ray intensity to scattered X-ray intensity remains constant for a certain deposition amount, even if the shape of the thin film sample or the fixing position of the sample changes.

[0005] In Non-Patent Document 1, CH, which is the main component of the resin thin film coated on the iron base material, ２ A method for quantifying O by the FP method has been disclosed. ２ O is a component that is difficult to measure with fluorescent X-rays. ２ The quantitative value of O is estimated using RhKα Compton scattering. Non-Patent Document 1 also describes that the measurement intensity ratio between RhKα Compton scattering and FeKα is calculated for shape correction.

[0006] Japanese Patent Application Laid-Open No. 2003-107020

[0007] "Advances in X-ray Analysis", Agne Technology Center, 40 (2009), pp. 233-241

[0008] A method for quantitatively analyzing the main components of a thin resin film coated on a base material using scattered radiation is known, as disclosed in Non-Patent Document 1. This method can reduce the influence of sample shape on the quantitative value compared to a method that treats the main components of the thin resin film as a balance.

[0009] However, the method disclosed in Non-Patent Document 1 performs shape correction using fluorescent X-rays originating from the main component of the base material, and is premised on the fact that fluorescent X-rays originating from the main component of the base material can penetrate a thin film. Therefore, it cannot be applied to samples using a base material with low fluorescent X-ray transmittance, such as aluminum.

[0010] Furthermore, the method disclosed in Non-Patent Document 1 determines the quantitative value of the main component in a resin thin film by utilizing the fact that the measured intensity of scattered radiation is proportional to the theoretical intensity. In an X-ray fluorescence analyzer, a sample is placed so as to cover an opening formed in a sample stage, and X-rays are irradiated through the opening from the sample mounting surface side. The X-ray fluorescence analyzer detects X-rays that pass through the opening among the X-rays returning from the sample, but cannot detect X-rays that penetrate deep into the sample and are scattered because they hit the sample stage and cannot pass through the opening.

[0011] When a bulk resin, which is a resin sample with a sufficient thickness, is used as a standard sample, X-rays that penetrate deep into the sample and are scattered cannot be detected. When a bulk resin is used as a standard sample, some scattered X-rays cannot be detected, and the proportional relationship between the measured intensity of scattered rays and the theoretical intensity does not hold. For this reason, bulk resin cannot be used as a standard sample in the method disclosed in Non-Patent Document 1.

[0012] The present disclosure has been made to solve such problems, and is a method for analyzing a target sample in which a thin film containing a resin is formed on a base material using the FP method, with one objective of expanding the scope of application of this analysis.

[0013] The disclosed X-ray fluorescence analysis method analyzes secondary X-rays obtained by irradiating a sample with primary X-rays from an X-ray source having a rhodium target. The X-ray fluorescence analysis method includes the steps of: extracting measured intensities of Compton scattered rays originating from rhodium from a spectrum of the target sample created based on secondary X-rays obtained by irradiating primary X-rays onto a target sample having a resin-containing thin film formed on a base material; extracting measured intensities of Rayleigh scattered rays originating from rhodium from the spectrum of the target sample; calculating a measured scattering intensity ratio, which is the ratio of the measured intensity of the Rayleigh scattered rays to the measured intensity of the Compton scattered rays, based on the measured intensities extracted from the spectrum of the target sample; and calculating the thickness of the thin film and the content of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of the Compton scattered rays is calculated based on a first arithmetic formula using the thickness of the thin film and the content of each element constituting the target sample as variables. The theoretical intensity of Rayleigh scattered radiation is calculated based on a second arithmetic expression having variables that are the thickness of the thin film and the contents of each element constituting the target sample. The step of calculating the thickness and contents of the thin film includes the steps of: substituting estimated values ​​for the variables included in the first arithmetic expression and the second arithmetic expression to calculate an estimated scattering intensity ratio calculated from the theoretical scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered radiation to the theoretical intensity of Compton scattered radiation; and updating the estimated value so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0014] The analytical program disclosed herein is for analyzing secondary X-rays obtained by irradiating a sample with primary X-rays from an X-ray source having a rhodium target. The analytical program causes a computer to execute the following steps: extracting measured intensities of Compton scattered rays originating from rhodium from a spectrum of the target sample created based on secondary X-rays obtained by irradiating a target sample having a resin-containing thin film formed on a base material with primary X-rays; extracting measured intensities of Rayleigh scattered rays originating from rhodium from the spectrum of the target sample; calculating a measured scattering intensity ratio, which is the ratio of the measured intensity of the Rayleigh scattered rays to the measured intensity of the Compton scattered rays, based on the measured intensities extracted from the spectrum of the target sample; and calculating the thickness of the thin film and the content of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of the Compton scattered rays is calculated based on a first arithmetic formula using the thickness of the thin film and the content of each element constituting the target sample as variables. The theoretical intensity of Rayleigh scattered radiation is calculated based on a second arithmetic expression having variables that are the thickness of the thin film and the contents of each element constituting the target sample. The step of calculating the thickness and contents of the thin film includes the steps of: substituting estimated values ​​for the variables included in the first arithmetic expression and the second arithmetic expression to calculate an estimated scattering intensity ratio calculated from the theoretical scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered radiation to the theoretical intensity of Compton scattered radiation; and updating the estimated value so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0015] The X-ray fluorescence analyzer disclosed herein includes a sample stage on which a sample is placed, an X-ray tube configured to irradiate primary X-rays from an X-ray source having a rhodium target toward the sample stage, a detector to detect secondary X-rays from the sample placed on the sample stage, and a control device to analyze the secondary X-rays detected by the detector. The sample is a target sample having a base material on which a thin film containing a resin is formed. The theoretical intensity of Compton scattered rays originating from rhodium contained in the secondary X-rays from the target sample is calculated based on a first arithmetic expression using the thickness of the thin film and the content of each element constituting the target sample as variables. The theoretical intensity of Rayleigh scattered rays originating from rhodium contained in the secondary X-rays from the target sample is calculated based on a second arithmetic expression using the thickness of the thin film and the content of each element constituting the target sample as variables. The control device creates an X-ray spectrum of the target sample based on the secondary X-rays, extracts the measured intensities of Compton scattered rays and Rayleigh scattered rays from the created X-ray spectrum, calculates a measured scattering intensity ratio, which is the ratio of the measured intensity of Rayleigh scattered rays to the measured intensity of Compton scattered rays, based on the extracted measured intensities, and calculates the thin film thickness and the contents of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample. The thin film thickness and the contents of each element constituting the target sample are calculated by substituting estimated values ​​for variables included in the first and second calculation formulas to calculate an estimated scattering intensity ratio obtained from the theoretical scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered rays to the theoretical intensity of Compton scattered rays, and updating the estimated values ​​so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0016] According to the present disclosure, it is possible to widen the range of applications when analyzing a target sample in which a thin film containing a resin is formed on a base material by the FP method.

[0017] It is a diagram showing an outline of the overall configuration of an X-ray fluorescence analyzer. It is a functional block diagram of a detector and a control device. It is a diagram showing an example of an X-ray spectrum stored in a spectrum storage unit. It is a flowchart showing an analysis method. It is a flowchart showing a method of calculating a sensitivity coefficient ratio.

[0018] [Overall Configuration of X-ray Fluorescence Spectrometer] Fig. 1 is a diagram showing the overall configuration of an X-ray fluorescence spectrometer. The X-ray fluorescence spectrometer 10 shown in Fig. 1 includes a sample chamber 1, a measurement chamber 5, a control device 14, an operation unit 15, and an output unit 16.

[0019] The X-ray fluorescence analyzer 10 is an energy dispersive X-ray fluorescence spectrometer (EDX) that measures the concentration of elements contained in a sample S. The spaces inside the sample chamber 1 and measurement chamber 5 are enclosed airtightly by a housing 3, and the inside can be kept vacuum as needed.

[0020] The sample chamber 1 is provided with a sample stage 2 at its bottom. A circular opening 4 is formed in the sample stage 2. The sample S is placed on the sample stage 2 so that the measurement position on the surface of the sample S is exposed from the opening 4 at the bottom of the housing 3.

[0021] The measurement chamber 5 is provided with an X-ray tube 7 and a detector 8 on its wall surface 6. The X-ray tube 7 irradiates primary X-rays toward the sample S. The primary X-rays emitted from the X-ray tube 7 are irradiated onto a measurement position on the sample S through the opening 4. Secondary X-rays obtained by irradiating the sample S with the primary X-rays are incident on the detector 8, and the energy and intensity of the secondary X-rays are measured.

[0022] A shutter 9, a primary X-ray filter 11, and a collimator 13 are installed in the measurement chamber 5. The shutter 9, the primary X-ray filter 11, and the collimator 13 are configured to be slidable by a drive mechanism 12 in a direction perpendicular to the plane of the paper in FIG.

[0023] The shutter 9 is made of an X-ray absorbing material such as lead, and can be inserted into the optical path of the primary X-rays to block the primary X-rays when necessary.

[0024] The primary X-ray filter 11 is made of a metal foil selected according to the purpose, and attenuates background components of the primary X-rays emitted from the X-ray tube 7 to improve the S / N ratio of required characteristic X-rays. In an actual device, a plurality of primary X-ray filters 11 made of different types of metal are used, and the primary X-ray filter 11 selected according to the purpose is inserted into the optical path of the primary X-rays by a drive mechanism 12.

[0025] The collimator 13 is an aperture with a circular opening in the center, and determines the size of the primary X-ray beam that irradiates the sample S. The collimator 13 is made of an X-ray absorbing material such as brass. In an actual device, multiple collimators 13 with different opening diameters are arranged side by side in a direction perpendicular to the plane of the paper in FIG. 1 , and the collimator 13 selected according to the purpose is inserted into the primary X-ray beam line by the driving mechanism 12.

[0026] In order to observe the measurement position of the sample S before or during measurement, an imaging unit 20 is installed at the bottom of the measurement chamber 5. That is, the imaging unit 20 is disposed opposite to the surface of the sample S, and is configured to image the measurement position of the sample S through an opening 4 formed in the sample stage 2.

[0027] Before measurement, the user performing the X-ray fluorescence analysis displays the image acquired by the image capturing unit 20 on the output unit 16 and adjusts the measurement position of the sample S while viewing this image. When managing the X-ray fluorescence measurement results, the image data of the measurement position is used as an identifier, and is stored and managed in association with the measurement results.

[0028] The control device 14 is mainly composed of a CPU (Central Processing Unit) 141, which is an arithmetic processing unit. A personal computer, for example, can be used as the control device 14. The X-ray tube 7, the detector 8, the operation unit 15, and the output unit 16 are connected to the control device 14.

[0029] The control device 14 controls the measurement by the X-ray fluorescence analyzer 10 based on measurement conditions input through an operation unit 15 including a keyboard, mouse, etc. Specifically, the control device 14 controls the tube voltage, tube current, irradiation time, etc. of the X-ray tube 7. The operation unit 15 may be a touch panel that is integrated with the display screen of the display device.

[0030] The control device 14 acquires data of the secondary X-rays detected by the detector 8. The control device 14 analyzes the sample S based on the spectrum of the secondary X-rays detected by the detector 8.

[0031] The output unit 16 includes a display device configured, for example, by an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence). The display device displays an image according to data transmitted from the control device 14. The display device can display various images generated by the control device 14. The display device can also display the analysis results by the control device 14 together with identification information for identifying the sample S (product name, product number, measurement position, etc.).

[0032] The control device 14 includes a CPU 141 and a memory 142 that stores various programs and data, including an analysis program 143. The memory 142 includes a read-only memory (ROM), a random access memory (RAM), and a solid-state drive (SSD). The memory 142 may include a hard disk drive (HDD) instead of the SSD.

[0033] The ROM stores various programs, including the analysis program 143, and various parameters executed by the CPU 141. The RAM temporarily stores data used during execution of the various programs in the CPU 141 and functions as a temporary data memory used as a work area. The SSD is a non-volatile storage device that stores the measurement results obtained by the X-ray fluorescence analyzer 10.

[0034] The analysis program 143 is a program for analyzing the sample S based on the spectrum of secondary X-rays detected by the detector 8. The CPU 141 reads and executes the analysis program 143 to realize each process (step) related to the analysis method described below.

[0035] The analysis program 143 can be provided as a program product by being recorded on a non-transitory computer-readable recording medium such as a flexible disk, a CD-ROM (Compact Disk Read Only Memory), a secondary storage device, a main storage device, or a memory card attached to a computer. Alternatively, the analysis program 143 can be provided by being recorded on a recording medium such as a hard disk built into a computer. The analysis program 143 can also be provided by being downloaded via a network.

[0036] [Functional Configuration of Control Device] Fig. 2 is a functional block diagram of the detector and control device. The CPU 141 executes various programs to perform the operations of the functional blocks of the control device 14 in Fig. 2.

[0037] The detector 8 includes an X-ray detector 81, a preamplifier 82, and a proportional amplifier 83. The control device 14 includes an A / D converter (ADC) 106, a multi-channel analyzer (MCA) 107, a spectrum storage unit 111, a parameter storage unit 112, and a data processing unit 200. Although not shown, the control device 14 also includes a control unit for controlling each device that constitutes the X-ray fluorescence analysis apparatus 10.

[0038] The X-ray tube 7 has a filament that emits thermoelectrons and a target T that converts the thermoelectrons into predetermined primary X-rays and emits the primary X-rays. The target T is rhodium (Rh). Therefore, the X-ray tube 7 is configured to irradiate the sample stage 2 with primary X-rays from an X-ray source having a rhodium target.

[0039] When the primary X-rays emitted from the X-ray tube 7 are irradiated onto the sample S, secondary X-rays excited by the primary X-rays are emitted from the sample S, and are incident on an X-ray detector 81 such as a silicon drift detector and detected as a current signal.

[0040] The detected current is integrated inside the X-ray detector 81, and the integrated value is reset after a certain period of time has elapsed. As a result, the output signal from the X-ray detector 81 becomes a stepped current pulse signal. This current pulse signal is input to a preamplifier 82 and further to a proportional amplifier 83 including a waveform shaping circuit, where it is shaped into a pulse of an appropriate shape having a wave height corresponding to the height of each step and is then output.

[0041] An A / D converter (ADC) 106 samples and digitizes this pulse waveform analog signal at a predetermined sampling period. A multi-channel analyzer (MCA) 107 discriminates each pulse by energy according to the peak value of the digitized pulse signal, and counts each pulse to create a pulse height distribution diagram, i.e., an X-ray spectrum, which is stored in a spectrum storage unit 111.

[0042] 3 is a diagram showing an example of an X-ray spectrum stored in the spectrum storage unit 111. As shown in Fig. 3, the secondary X-rays include fluorescent X-rays specific to each element contained in the sample S (FeKα, ZnKα, etc. in the diagram), as well as Rayleigh scattered rays (RhKαR in the diagram) and Compton scattered rays (RhKαC in the diagram) that have bounced off the sample S.

[0043] The data processing unit 200 analyzes the X-ray spectrum stored in the spectrum storage unit 111 based on the analysis conditions input from the operation unit 15 and various parameters such as physical constants (fundamental parameters) stored in the parameter storage unit 112, and outputs the analysis results to the output unit 16.

[0044] In this embodiment, the data processing unit 200 uses the FP method to analyze the X-ray spectrum obtained from the sample S. A specific analysis method will be described below.

[0045] [Analysis Method] The following describes a method for analyzing an X-ray spectrum by the data processing unit 200. As an example, the X-ray fluorescence analyzer 10 according to this embodiment analyzes a sample S in which a thin film F is formed on a base material B, as shown in FIG.

[0046] When quantifying elements in a thin film, the fluorescent X-ray intensity obtained from the thin film is lower than that obtained from a sufficiently thick bulk material. Therefore, when quantifying elements in a thin film by fluorescent X-ray analysis, it is necessary to take the film thickness into consideration.

[0047] The data processing unit 200 according to this embodiment obtains the composition of the sample S and the thickness t of the thin film F as the analysis results by the FP method.

[0048] 4 is a flowchart showing the analysis method. Each process (step) shown in FIG. 4 is executed by the control device 14, and is realized by the CPU 141 executing various programs including the analysis program 143.

[0049] In step S1, the control device 14 acquires an X-ray spectrum by irradiating the sample S with primary X-rays from the X-ray tube 7 and detecting secondary X-rays from the sample S with the detector 8. The acquired X-ray spectrum is stored in the spectrum storage unit 111.

[0050] In step S2, the control device 14 extracts the intensity of each spectral line appearing in the acquired X-ray spectrum. The control device 14 determines the spectral lines to be extracted based on, for example, analysis conditions input from the operation unit 15. The analysis conditions input from the operation unit 15 include the substance constituting the base material B and the substance constituting the thin film F. Note that "substance" includes at least one of a compound and an element.

[0051] In step S2, the processes of steps S21 to S23 are executed. In step S21, the control device 14 calculates the measured intensity M Ｃ Extract.

[0052] In step S22, the control device 14 calculates the measured intensity MＲ Extract.

[0053] In step S23, the control device 14 calculates the measured intensity M ｆｉ is extracted for each inorganic element that constitutes the sample S.

[0054] In step S3, the control device 14 calculates the actual scattering intensity ratio M from the measured intensities extracted in step S2. Ｃ／Ｒ The actual scattering intensity ratio M Ｃ／Ｒ is the measured intensity of the Compton scattering ray M Ｃ The measured intensity M of the Rayleigh scattering ray Ｒ and is calculated based on formula (1).

[0055]

[0056] In step S4, the control device 14 calculates the measured fluorescent X-ray intensity ratio M of the fluorescent X-rays derived from the element i from the measured intensities extracted in step S2. ｆｉ／Ｒ is calculated for each inorganic element constituting the sample S. The measured fluorescent X-ray intensity ratio M ｆｉ／Ｒ is the measured intensity M of the fluorescent X-rays from element i ｆｉ The measured intensity M of the Rayleigh scattering ray Ｒ and is calculated based on formula (2).

[0057]

[0058] In step S5, the control device 14 calculates the theoretical intensity of each spectral line, and executes the processes of steps S51 to S53.

[0059] In step S51, the control device 14 calculates the theoretical intensity T of the Compton scattered radiation based on the following equation (3): Ｃ Calculate.

[0060]

[0061] W is the content of the element. The subscripts i1, i2, ... indicate the type of element and represent all elements constituting the sample S. t is the film thickness of the thin film F. The elements constituting the sample S are identified from the substances constituting the base material B and the substances constituting the thin film F, which are input as analysis conditions from the operation unit 15. The content W is a variable equivalent to the "content," as the content can be determined by multiplying the content by the weight of the sample S.

[0062] As shown in equation (3), the theoretical intensity T of the Compton scattered radiation Ｃ is the content W of each element constituting the sample S ｉ１， W ｉ２， ... and the thickness t of the thin film F as variables. Equation (3) includes various parameters, and the control device 14 calculates the theoretical intensity T by substituting the various parameters stored in the parameter storage unit 112 and the initial values ​​of the variables input from the operation unit 15 as analysis conditions or the estimated values ​​after correction in steps S9 and S10 into equation (3). Ｃ The initial values ​​may be input directly from the operation unit 15, or may be determined by the control device 14 based on the elements constituting the sample S. When the control device 14 determines the initial values ​​based on the elements constituting the sample S, for example, in the case where the sample S is composed of five elements, the control device 14 sets the initial value of each element to 20%. The estimated values ​​corrected in steps S9 and S10 will be described later, and hereinafter will also be simply referred to as "corrected estimated values."

[0063] In step S52, the control device 14 calculates the theoretical intensity T of the Rayleigh scattered radiation based on the following equation (4): Ｒ Calculate.

[0064]

[0065] Theoretical intensity of Rayleigh scattering T Ｒ is the theoretical intensity T of the Compton scattered ray as shown in equation (4). ＣSimilarly, it is expressed by a theoretical formula with variables being the content of each element constituting the sample S and the thickness t of the thin film F. The control device 14 substitutes various parameters stored in the parameter storage unit 112 and the initial values ​​or corrected estimated values ​​of the variables input from the operation unit 15 as analysis conditions into formula (4), thereby calculating the theoretical intensity T Ｒ Calculate.

[0066] In step S53, the control device 14 calculates the theoretical intensity T of the fluorescent X-rays originating from the element i based on the following formula (5): ｆｉ is calculated for each inorganic element constituting the sample S.

[0067]

[0068] T ｆｉ is the theoretical intensity of the fluorescent X-rays originating from element i. As shown in formula (5), the theoretical intensity T ｆｉ is expressed by a theoretical formula with the film thickness t and the content of element i as variables. The control device 14 calculates the theoretical intensity T of the fluorescent X-rays originating from element i by substituting various parameters stored in the parameter storage unit 112 and the initial values ​​or corrected estimated values ​​of the variables input from the operation unit 15 as analysis conditions into formula (5). ｆｉ Calculate.

[0069] Note that, since the mechanisms of generation of Compton scattered rays, Rayleigh scattered rays, and fluorescent X-rays derived from each element are different from one another, formulas (3) to (5) are different from one another. Furthermore, the theoretical formulas of formulas (3) to (5) are each determined based on the mechanism of generation of spectral lines and are publicly known. Therefore, detailed explanation of formulas (3) to (5) will be omitted.

[0070] In step S6, the control device 14 calculates the estimated scattering intensity ratio E based on the following equation (6): Ｃ／Ｒ Calculate.

[0071]

[0072] k Ｃ／Ｒ is the sensitivity coefficient ratio, and the sensitivity coefficient k of the Compton scattering ray Ｃ The sensitivity coefficient k of Rayleigh scattering to ＲThe sensitivity coefficient ratio k Ｃ／Ｒ is obtained by measuring a standard sample whose composition ratio is known, and is stored in the parameter storage unit 112. Ｃ／Ｒ A specific calculation method will be described later with reference to FIG.

[0073] In step S7, the control device 14 calculates an estimated fluorescent X-ray intensity ratio E for the element i based on the following equation (7): ｆｉ／Ｒ is calculated for each inorganic element constituting the sample S.

[0074]

[0075] k ｆｉ／Ｒ is the sensitivity coefficient ratio of the fluorescent X-rays originating from element i, and the sensitivity coefficient k of the fluorescent X-rays originating from element i ｆｉ The sensitivity coefficient k of Rayleigh scattering to Ｒ The sensitivity coefficient ratio k ｆｉ／Ｒ is obtained by measuring a standard sample containing element i and having a known content of each element, and is stored in the parameter storage unit 112. ｆｉ／Ｒ A specific calculation method will be described later with reference to FIG.

[0076] In step S8, the control device 14 calculates the estimated scattering intensity ratio E Ｃ／Ｒ is the measured scattering intensity ratio M Ｃ／Ｒ and the estimated fluorescent X-ray intensity ratio E ｆｉ／Ｒ is the measured fluorescent X-ray intensity ratio M ｆｉ／Ｒ For example, the control device 14 determines whether the estimated scattering intensity ratio E Ｃ／Ｒ and the measured scattering intensity ratio M Ｃ／Ｒ The difference between the estimated fluorescent X-ray intensity ratio E ｆｉ／Ｒ and the measured fluorescent X-ray intensity ratio M ｆｉ／Ｒ When the difference between the first threshold value and the second threshold value is smaller than a predetermined second threshold value, it is determined that convergence has occurred. The first threshold value and the second threshold value may be determined in advance, and may be determined based on, for example, a required accuracy.

[0077] The method for determining convergence is not limited to the above-described method. For example, the control device 14 may determine that convergence has occurred when the difference between the estimated value before correction and the estimated value after correction is smaller than a predetermined third threshold value.

[0078] If it is determined that convergence has not occurred (NO in step S8), the control device 14 executes the processes of steps S9 and S10, and then executes the processes of step S5 and subsequent steps again.

[0079] In step S9, the control device 14 calculates the content W of each element. ｉ１， W ｉ２ ... is corrected in a direction that causes the estimated intensity ratio to converge to the actually measured intensity ratio.

[0080] In step S10, the corrected content W ｉ１， W ｉ２ The film thickness t is corrected so that the total value approaches 100%.

[0081] In steps S5 to S7, the control device 14 calculates the content W of each element corrected in steps S9 and S10. ｉ１， W ｉ２ ... and the film thickness t are substituted into the above formulas (3) to (5) to obtain the theoretical strength T Ｃ , T Ｒ , T ｆｉ is calculated and the estimated scattering intensity ratio E Ｃ／Ｒ , and the estimated fluorescent X-ray intensity ratio E ｆｉ／Ｒ Ask for.

[0082] The control device 14 repeats the processes of steps S9, S10, and S5 to S7 until convergence is achieved.

[0083] If it is determined that convergence has occurred (YES in step S8), in step S11, the control device 14 outputs the analysis result to the output unit 16. More specifically, the estimated scattering intensity ratio E Ｃ／Ｒ , and the estimated fluorescent X-ray intensity ratio E ｆｉ／Ｒ The content of each element W ｉ１ , W ｉ２ . . . and the film thickness t are output as the content of each element constituting the sample S and the film thickness t of the thin film F.

[0084] In the above embodiment, the elements constituting the sample S are identified by inputting them from the operation unit 15, but they may also be identified by qualitatively analyzing the obtained spectrum.

[0085] [Method for calculating the sensitivity coefficient ratio] Fig. 5 is a flowchart showing a method for calculating the sensitivity coefficient ratio. Ｃ／Ｒ The sensitivity coefficient ratio k can be calculated from the X-ray spectrum of a standard sample with a known element content. ｆｉ／Ｒ is determined from the X-ray spectrum of a standard sample containing inorganic elements contained in the sample to be analyzed and having a known content of each element. Each process (step) shown in FIG. 5 is executed by the control device 14, and is realized by the CPU 141 executing various programs including the analysis program 143. In the following, as an example, the sensitivity coefficient ratio k Ｃ／Ｒ and the lead sensitivity coefficient ratio k ｆＰｂ／Ｒ and the iron sensitivity coefficient ratio k ｆＦｅ／Ｒ The following is required.

[0086] Each sensitivity coefficient ratio can be determined from the X-ray spectrum of a standard sample. A standard sample is a substance whose constituent elements are known and whose content of each constituent element is known. In the following example, the sensitivity coefficient ratio k Ｃ／Ｒ is determined from the X-ray spectrum of the first standard sample, and the sensitivity coefficient ratio k ｆＰｂ／Ｒ and the iron sensitivity coefficient ratio k ｆＦｅ／Ｒ is determined from the X-ray spectrum of the second standard sample. The first standard sample is a bulk resin, which is a mass of resin with known elemental contents. The second standard sample is a bulk metal containing lead and iron, with known elemental contents. Note that the bulk resin and bulk metal each need only have a thickness that does not require consideration of film thickness in the FP method.

[0087] First, the control device 14 executes steps S110 to S150 to obtain the sensitivity coefficient ratio k Ｃ／Ｒ In step S110, the control device 14 acquires the X-ray spectrum of the first standard sample.

[0088] In step S120, the control device 14 extracts the measured intensity of each spectral line. In step S120, the processes of steps S121 and S122 are executed.

[0089] In step S121, the control device 14 calculates the measured intensity M Ｃ More specifically, the control device 14 extracts the measured intensity M of the Compton scattered radiation from the X-ray spectrum of the first standard sample. Ｃ Extract.

[0090] In step S122, the control device 14 calculates the measured intensity M Ｒ More specifically, the control device 14 extracts the measured intensity M of the Rayleigh scattered rays from the X-ray spectrum of the first standard sample. Ｒ Extract.

[0091] In step S130, the control device 14 calculates the measured intensity M extracted in steps S121 and S122. Ｃ and the measured intensity M Ｒ From the above, the measured scattering intensity ratio M Ｃ／Ｒ Ask for.

[0092] In step S140, the control device 14 calculates the theoretical intensity of each spectral line. In step S140, the processes of steps S141 and S142 are executed.

[0093] In step S141, the control device 14 calculates the theoretical intensity T of the Compton scattered radiation for the first standard sample based on the above-mentioned formula (3). Ｃ The theoretical strength T Ｃ When the standard sample is a thin film, the control device 14 substitutes the film thickness of the thin film into equation (3).

[0094] In step S142, the control device 14 calculates the theoretical intensity T of the Rayleigh scattered radiation for the first standard sample based on the above-mentioned formula (4). ＲThe film thickness t is set to infinity or an appropriate sufficiently large value, as in step S141. If the standard sample is a thin film, the control device 14 substitutes the film thickness of the thin film into equation (4).

[0095] In step S150, the control device 14 applies the measured scattering intensity ratio M calculated in steps S130 and S140 to the following equation (8): Ｃ／Ｒ , the theoretical intensity of the Compton scattering ray T Ｃ , and the theoretical intensity of the Rayleigh scattered radiation T Ｒ By substituting, the sensitivity coefficient ratio k Ｃ／Ｒ Calculate.

[0096]

[0097] Next, the control device 14 executes steps S160 to S200 to obtain the sensitivity coefficient ratio k ｆＰｂ／Ｒ and the iron sensitivity coefficient ratio k ｆＦｅ／Ｒ In step S160, the control device 14 acquires the X-ray spectrum of the second standard sample.

[0098] In step S170, the control device 14 extracts the measured intensity of each spectral line. In step S170, the processes of steps S171 and S172 are executed.

[0099] In step S171, the control device 14 calculates the measured intensity M ｆｉ More specifically, the control device 14 extracts the measured intensity M of fluorescent X-rays derived from lead from the X-ray spectrum of the second standard sample. ｆＰｂ and the measured intensity of fluorescent X-rays from iron, M ｆＦｅ Extract the following.

[0100] In step S172, the control device 14 calculates the measured intensity M Ｒ More specifically, the control device 14 extracts the measured intensity M of the Rayleigh scattered rays from the X-ray spectrum of the second standard sample. Ｒ Extract.

[0101] In step S180, the control device 14 calculates the measured intensity M of the fluorescent X-rays derived from the element i extracted in steps S171 and S172. ｆｉ and the measured intensity of Rayleigh scattered radiation M Ｒ From the above, the measured fluorescent X-ray intensity ratio M ｆｉ／Ｒ More specifically, the control device 14 calculates the measured fluorescent X-ray intensity ratio M ｆＰｂ／Ｒ and the measured fluorescent X-ray intensity ratio of iron M ｆＦｅ／Ｒ and asks for.

[0102] In step S190, the control device 14 calculates the theoretical intensity of each spectral line. In step S190, the processes of steps S191 and S192 are executed.

[0103] In step S191, the control device 14 calculates the theoretical intensity T of the fluorescent X-rays derived from each inorganic element based on the above-mentioned formula (5). ｆｉ More specifically, in this embodiment, the control device 14 calculates the theoretical intensity T of fluorescent X-rays derived from lead for the second standard sample. ｆＰｂ and the theoretical intensity T of the fluorescent X-rays from iron ｆＦｅ The film thickness t is set to infinity or an appropriate sufficiently large value, as in step S141. If the standard sample is a thin film, the control device 14 substitutes the film thickness of the thin film into equation (5).

[0104] In step S192, the theoretical intensity T of the Rayleigh scattered radiation for the second standard sample is calculated based on the above-mentioned formula (4). Ｒ The film thickness t is set to infinity or an appropriate sufficiently large value, as in step S141. If the standard sample is a thin film, the control device 14 substitutes the film thickness of the thin film into equation (4).

[0105] In step S200, the control device 14 applies the measured fluorescent X-ray intensity ratio M calculated in steps S180 and S190 to the following equation (9): ｆｉ／Ｒ , the theoretical intensity of fluorescent X-rays T ｆｉ , and the theoretical intensity of the Rayleigh scattered radiation T Ｒ By substituting the above, the fluorescent X-ray sensitivity coefficient ratio k ｆｉ／ＲMore specifically, the sensitivity coefficient ratio k ｆＰｂ／Ｒ is the measured fluorescent X-ray intensity ratio of lead, M ｆＰｂ／Ｒ , theoretical strength of lead T ｆＰｂ , and the theoretical intensity of the Rayleigh scattered radiation T Ｒ The iron sensitivity coefficient ratio k can be calculated by substituting the above into equation (9). ｆＦｅ／Ｒ is the measured fluorescent X-ray intensity ratio of iron, M ｆＦｅ／Ｒ , the theoretical strength of iron T ｆＦｅ , and the theoretical intensity of the Rayleigh scattered radiation T Ｒ can be obtained by substituting into equation (9).

[0106]

[0107] In step S210, the control device 14 stores the sensitivity coefficient ratios calculated in steps S150 and S200 in the parameter storage unit 112, and then ends the process.

[0108] In FIG. 5, a bulk resin is used as the first standard sample, and the control device 14 calculates the sensitivity coefficient ratio k from the X-ray spectrum of the first standard sample. Ｃ／Ｒ The control device 14 calculated the sensitivity coefficient ratio k from the X-ray spectrum of the second standard sample, which is a bulk metal. Ｃ／Ｒ It is preferable to determine the sensitivity coefficient ratio using a standard sample whose components are similar to those of the target sample to be measured, but it may also be determined using a standard sample whose components are different from those of the target sample.

[0109] [Examples and Comparative Examples] The accuracy of the analytical values ​​obtained by the analytical method according to the present embodiment was examined. Sample S was a paper clip coated with a resin. The base material was iron (Fe) and the resin was polyethylene (C). ２ H ４ Quantitative analysis of lead (Pb) in the resin coating of sample S was performed according to the analysis method of this embodiment and the calibration curve method. The analysis results and the respective analysis conditions are shown in Table 1.

[0110]

[0111] In the examples, quantitative analysis of lead in the resin coating of sample S was carried out according to the analytical method of this embodiment. In the examples, sample S was placed on sample stage 2 without being destroyed, and the obtained X-ray spectrum was analyzed according to the analytical method shown in Fig. 4. Note that each sensitivity coefficient ratio was determined by the method shown in Fig. 5 using bulk polyethylene, iron, and lead as standard samples.

[0112] In Comparative Example 1, the sample S was placed on the sample stage 2 without being destroyed, and the obtained X-ray spectrum was analyzed according to the calibration curve method. In Comparative Example 2, the sample S was destroyed, the resin coating was removed from the base material, and only the resin coating was placed on the sample stage 2, and the obtained X-ray spectrum was analyzed according to the calibration curve method.

[0113] The calibration curve method in Comparative Examples 1 and 2 is a quantitative analysis technique in which a calibration curve is drawn based on the correlation between the intensity of fluorescent X-rays derived from lead in the X-ray spectrum obtained by measuring a standard sample with a known lead content and the lead content. Note that the calibration curve methods in Comparative Examples 1 and 2 employ a known method in which a calibration curve is created based on the ratio of the measured fluorescent X-ray intensity of lead to the intensity of continuous scattered X-rays near the fluorescent X-rays of lead, thereby correcting for the influence of sample shape.

[0114] In Comparative Example 1, the analysis was performed without separating the base material and the thin film, and therefore the analytical value of lead was lower than in the cases of analysis by other methods. This is because, although shape correction was performed in Comparative Example 1, the calibration curve method cannot measure the film thickness of the thin film, and therefore the analysis value was affected by the film thickness.

[0115] In Comparative Example 2, the base material and the thin film were separated and only the thin film was measured, so the film thickness was also corrected as part of the shape. As a result, the analytical value in Comparative Example 2 was higher than that in Comparative Example 1.

[0116] In this way, in the case of the calibration curve method, highly accurate analytical results can be obtained by separating the base material from the thin film and measuring only the thin film.

[0117] The analytical results in the example were close to those in the comparative example 2. That is, by using the analytical method according to the present embodiment, the target component in the resin thin film can be measured accurately without destroying the sample S.

[0118] [Effects of Using Scattering Intensity Ratio] As shown in Table 1, by using the analysis method according to this embodiment, it is possible to measure the target component in the resin thin film without destroying the sample S. Therefore, the analysis method according to this embodiment can be applied to samples that cannot be destroyed, such as those that are shipped as products after measurement or are incorporated into products.

[0119] In addition, the analysis method according to this embodiment uses the ratio of the intensity of Rayleigh scattered radiation to the intensity of Compton scattered radiation, and normalization is performed by dividing the intensity of Compton scattered radiation by the intensity of Rayleigh scattered radiation, thereby correcting the effect of the shape of the sample S on the quantitative value.

[0120] As a comparative example, when normalization is performed using fluorescent X-rays originating from the base material, if the transmittance of the fluorescent X-rays is low relative to the thin film, the fluorescent X-rays cannot be detected and therefore cannot be used. In particular, if the base material B of sample S is primarily composed of a light element with an atomic number of 21 or less (scandium), the fluorescent X-rays of that element have low energy and are difficult to transmit through the thin film, making them difficult to detect with the X-ray fluorescence analyzer 10. In contrast, Rayleigh scattered rays can be detected regardless of the type of base material. Therefore, according to the method of this embodiment, normalization is performed using the intensity of Rayleigh scattered rays, making it possible to analyze samples S with resin thin films formed thereon, regardless of the base material of sample S, thereby broadening the scope of application of the FP method. In other words, according to the method of this embodiment, it is possible to analyze samples containing base materials primarily composed of light elements with atomic numbers of 21 or less.

[0121] Furthermore, in this embodiment, by using the ratio of the intensity of Rayleigh scattered radiation to the intensity of Compton scattered radiation, it is possible to use bulk resin, which is a mass of resin, as a standard sample. The reason for this will be explained below.

[0122] It is known that the measured intensity of scattered rays is proportional to the theoretical intensity. The penetration depth of primary X-rays is deeper in resin materials than in metal materials. As shown in Figure 1, scattered rays I1 of primary X-rays that are incident near the surface of sample S pass from sample S through opening 4 and enter detector 8. On the other hand, scattered rays I2 of primary X-rays that are incident deep into sample S hit sample stage 2 and do not reach detector 8.

[0123] Therefore, when bulk resin is used as a standard sample, the intensity of the scattered rays I2 of the primary X-rays that have penetrated deep into the sample S cannot be detected, and the proportional relationship between the measured intensity and the theoretical intensity of the scattered rays is lost, making it impossible to determine the sensitivity coefficient.

[0124] Here, since both Compton scattered radiation and Rayleigh scattered radiation are scattered radiation, some scattered radiation cannot be detected for either type of scattered radiation. By using the scattering intensity ratio, the influence of the undetectable scattered radiation can be canceled out, so the sensitivity coefficient ratio can be calculated even when bulk resin is used as the standard sample. As a result, bulk resin can be used as the standard sample.

[0125] As described above, by using the analysis method according to this embodiment, the range of application of analysis by the FP method can be expanded.

[0126] In the above embodiment, the analysis was performed using Compton scattered radiation and Rayleigh scattered radiation derived from RhKα, but if sufficient intensity is obtained, analysis by the FP method can also be performed using Compton scattered radiation and Rayleigh scattered radiation derived from RhKβ.

[0127] In the above embodiment, the control device 14 calculates the theoretical intensity T Ｃ and the theoretical intensity T of the Rayleigh scattering ray Ｒ and then calculate the estimated scattering intensity ratio E Ｃ／Ｒ The control device 14 calculated the theoretical intensity T Ｃ and the theoretical intensity T of the Rayleigh scattering ray Ｒ and , respectively, the estimated scattering intensity ratio E Ｃ／Ｒ may be calculated.

[0128] Aspects It will be understood by those skilled in the art that the above-described embodiments are specific examples of the following aspects.

[0129] (Item 1) One aspect of the X-ray fluorescence analysis method is a method for analyzing secondary X-rays obtained by irradiating a sample with primary X-rays from an X-ray source having a rhodium target. The X-ray fluorescence analysis method includes the steps of: extracting measured intensities of Compton scattered rays originating from rhodium from a spectrum of the target sample created based on secondary X-rays obtained by irradiating primary X-rays onto a target sample having a resin-containing thin film formed on a base material; extracting measured intensities of Rayleigh scattered rays originating from rhodium from the spectrum of the target sample; calculating a measured scattering intensity ratio, which is the ratio of the measured intensity of the Rayleigh scattered rays to the measured intensity of the Compton scattered rays, based on the measured intensities extracted from the spectrum of the target sample; and calculating the thickness of the thin film and the content of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of the Compton scattered rays is calculated based on a first arithmetic formula using the thickness of the thin film and the content of each element constituting the target sample as variables. The theoretical intensity of Rayleigh scattered radiation is calculated based on a second arithmetic expression having variables that are the thickness of the thin film and the contents of each element constituting the target sample. The step of calculating the thickness and contents of the thin film includes the steps of: substituting estimated values ​​for the variables included in the first arithmetic expression and the second arithmetic expression to calculate an estimated scattering intensity ratio calculated from the theoretical scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered radiation to the theoretical intensity of Compton scattered radiation; and updating the estimated value so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0130] According to the X-ray fluorescence analysis method described in paragraph 1, the use of the scattering intensity ratio can broaden the scope of application of the FP method. More specifically, the FP method can be used to analyze samples in which a resin thin film is formed on a base material whose main component is an element that is difficult to measure with fluorescent X-rays, without destroying the sample. Furthermore, because primary X-rays penetrate deep into the resin component, scattered X-rays that penetrate deep and bounce back may not be detected. Even in this case, the scattering intensity ratio can be used to cancel out the effects of undetectable scattered X-rays, allowing the bulk resin to be used as a standard sample. Therefore, analysis using the FP method can be performed even when it is difficult to prepare a thin-film standard sample.

[0131] (Item 2) In the X-ray fluorescence analysis method described in Item 1, the thin film contains at least one inorganic component. The theoretical intensity of the fluorescent X-rays originating from the inorganic component is calculated based on a third arithmetic expression using the thickness of the thin film and the content of the inorganic component as variables. The X-ray fluorescence analysis method further includes the steps of detecting spectral lines due to the fluorescent X-rays originating from the inorganic component from the spectrum of the target sample and extracting measured fluorescent X-ray intensities, which are the measured intensities of the fluorescent X-rays originating from the inorganic component, and calculating a measured fluorescent X-ray intensity ratio, which is the ratio of the measured intensity of the fluorescent X-rays originating from the inorganic component to the measured intensity of the Rayleigh scattered rays, based on the measured intensities extracted from the spectrum of the target sample. The step of calculating the thickness and content of the thin film further includes the steps of substituting estimated values ​​for the variables included in the second and third arithmetic expressions to calculate an estimated fluorescent X-ray intensity ratio from the theoretical fluorescent X-ray intensity ratio, which is the ratio of the theoretical intensity of the fluorescent X-rays originating from the inorganic component to the theoretical intensity of the Rayleigh scattered rays. In the step of updating the estimated values, the estimated values ​​are updated so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio and the estimated fluorescent X-ray intensity ratio converges to the measured fluorescent X-ray intensity ratio.

[0132] According to the fluorescent X-ray analysis method described in the second paragraph, the content of inorganic components in the thin film resin can be determined.

[0133] (Item 3) In the fluorescent X-ray analysis method according to item 1 or 2, the Rayleigh scattered radiation is Rayleigh scattered radiation derived from RhKα. The Compton scattered radiation is Rayleigh scattered radiation derived from RhKα.

[0134] According to the X-ray fluorescence analysis method described in the third aspect, the analysis accuracy can be improved by using scattered radiation derived from RhKα, which has a higher intensity than RhKβ, for analysis.

[0135] (Item 4) In the fluorescent X-ray analysis method according to any one of items 1 to 3, the base material is mainly composed of a light element having an atomic number of 21 or less.

[0136] According to the X-ray fluorescence analysis method described in the fourth aspect, the FP method can be applied to a sample in which a resin thin film is formed on a base material whose main component is an element that is difficult to measure with fluorescent X-rays.

[0137] (Item 5) In the X-ray fluorescence analysis method according to any one of Items 1 to 4, the estimated scattering intensity ratio is determined by multiplying the theoretical scattering intensity ratio by the sensitivity coefficient ratio. The X-ray fluorescence analysis method further includes the steps of: using a bulk resin having a known content of each element as a standard sample, extracting measured intensities of Compton scattered rays from a spectrum of the standard sample obtained by irradiating the standard sample with primary X-rays; extracting measured intensities of Rayleigh scattered rays from the spectrum of the standard sample; determining the measured scattering intensity ratio of the standard sample based on the measured intensities extracted from the spectrum of the standard sample; and determining the sensitivity coefficient ratio from the theoretical scattering intensity ratio of the standard sample, which is determined by substituting the content of each element constituting the standard sample and the thickness of the standard sample, based on a first arithmetic formula and a second arithmetic formula.

[0138] According to the fluorescent X-ray analysis method described in item 5, even when it is difficult to prepare a standard thin film sample, analysis by the FP method can be performed.

[0139] (Item 6) An analysis program according to one aspect is an analysis program for analyzing secondary X-rays obtained by irradiating a sample with primary X-rays from an X-ray source having a rhodium target. The analysis program causes a computer to execute the following steps: extracting measured intensities of Compton scattered rays originating from rhodium from a spectrum of the target sample created based on secondary X-rays obtained by irradiating primary X-rays onto a target sample having a resin-containing thin film formed on a base material; extracting measured intensities of Rayleigh scattered rays originating from rhodium from the spectrum of the target sample; calculating a measured scattering intensity ratio, which is the ratio of the measured intensity of the Rayleigh scattered rays to the measured intensity of the Compton scattered rays, based on the measured intensities extracted from the spectrum of the target sample; and calculating the thickness of the thin film and the content of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of the Compton scattered rays is calculated based on a first arithmetic formula using the thickness of the thin film and the content of each element constituting the target sample as variables. The theoretical intensity of Rayleigh scattered radiation is calculated based on a second arithmetic expression having variables that are the thickness of the thin film and the contents of each element constituting the target sample. The step of calculating the thickness and contents of the thin film includes the steps of: substituting estimated values ​​for the variables included in the first arithmetic expression and the second arithmetic expression to calculate an estimated scattering intensity ratio calculated from the theoretical scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered radiation to the theoretical intensity of Compton scattered radiation; and updating the estimated value so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0140] (Item 7) An X-ray fluorescence analyzer according to one aspect includes a sample stage on which a sample is placed, an X-ray tube configured to irradiate primary X-rays from an X-ray source having a rhodium target toward the sample stage, a detector to detect secondary X-rays from the sample placed on the sample stage, and a control device to analyze the secondary X-rays detected by the detector. The sample is a target sample having a base material on which a thin film containing a resin is formed. The theoretical intensity of Compton scattered rays originating from rhodium contained in secondary X-rays from the target sample is calculated based on a first arithmetic expression using the thickness of the thin film and the content of each element constituting the target sample as variables. The theoretical intensity of Rayleigh scattered rays originating from rhodium contained in secondary X-rays from the target sample is calculated based on a second arithmetic expression using the thickness of the thin film and the content of each element constituting the target sample as variables. The control device creates an X-ray spectrum of the target sample based on the secondary X-rays, extracts the measured intensities of Compton scattered rays and Rayleigh scattered rays from the created X-ray spectrum, calculates a measured scattering intensity ratio, which is the ratio of the measured intensity of Rayleigh scattered rays to the measured intensity of Compton scattered rays, based on the extracted measured intensities, and calculates the thin film thickness and the contents of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample. The thin film thickness and the contents of each element constituting the target sample are calculated by substituting estimated values ​​for variables included in the first and second calculation formulas to calculate an estimated scattering intensity ratio obtained from the theoretical scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered rays to the theoretical intensity of Compton scattered rays, and updating the estimated values ​​so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0141] According to the analysis program described in paragraph 6 and the X-ray fluorescence analyzer described in paragraph 7, the scope of application of the FP method can be expanded by using the scattering intensity ratio. More specifically, the FP method can be used to analyze samples in which a resin thin film is formed on a base material whose main component is an element that is difficult to measure with fluorescent X-rays, without destroying the sample. Furthermore, because primary X-rays penetrate deep into the resin component, scattered X-rays that penetrate deep and bounce back may not be detected. Even in this case, the scattering intensity ratio can be used to cancel out the effects of undetectable scattered X-rays, allowing the bulk resin to be used as a standard sample. Therefore, analysis using the FP method can be performed even when it is difficult to prepare a thin-film standard sample.

[0142] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0143] REFERENCE SIGNS LIST 1 Sample chamber, 2 Sample stage, 3 Housing, 4 Opening, 5 Measurement chamber, 6 Wall, 7 X-ray tube, 8 Detector, 9 Shutter, 10 X-ray fluorescence analyzer, 11 X-ray filter, 12 Drive mechanism, 13 Collimator, 14 Control device, 15 Operation unit, 16 Output unit, 20 Imaging unit, 81 X-ray detector, 82 Preamplifier, 83 Proportional amplifier, 106 A / D converter, 107 Multichannel analyzer, 111 Spectrum storage unit, 112 Parameter storage unit, 142 Memory, 143 Analysis program, 200 Data processing unit.

Claims

1. 1. A method for X-ray fluorescence analysis comprising: irradiating a sample with primary X-rays from an X-ray source having a rhodium target; and analyzing secondary X-rays obtained by the irradiation, the method comprising the steps of: A step of extracting a measured intensity of Compton scattered radiation originating from rhodium from a spectrum of a target sample that is created based on the secondary X-rays obtained by irradiating the target sample with the primary X-rays, the target sample having a base material formed with a thin film containing a resin; Extracting the measured intensity of Rayleigh scattered radiation originating from rhodium from the spectrum of the target sample; determining a measured scattering intensity ratio, which is a ratio of the measured intensity of the Rayleigh scattered radiation to the measured intensity of the Compton scattered radiation, based on each measured intensity extracted from the spectrum of the target sample; determining a thickness of the thin film and a content of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample; the theoretical intensity of the Compton scattered radiation is calculated based on a first calculation formula having variables of the thickness of the thin film and the contents of each element constituting the target sample; the theoretical intensity of the Rayleigh scattered radiation is calculated based on a second calculation formula having variables of the thickness of the thin film and the contents of each element constituting the target sample; The step of determining the thickness and the content of the thin film includes: a step of substituting estimated values ​​for variables included in the first and second arithmetic expressions to obtain an estimated scattering intensity ratio obtained from a theoretical scattering intensity ratio which is a ratio of the theoretical intensity of the Rayleigh scattering radiation to the theoretical intensity of the Compton scattering radiation; updating the estimated value so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

2. The thin film comprises at least one inorganic component; a theoretical intensity of the fluorescent X-rays originating from the inorganic component is calculated based on a third calculation formula having a thickness of the thin film and a content of the inorganic component as variables; detecting spectral lines due to fluorescent X-rays originating from the inorganic components from the spectrum of the target sample, and extracting measured fluorescent X-ray intensity, which is the measured intensity of the fluorescent X-rays originating from the inorganic components; and calculating an actual fluorescent X-ray intensity ratio, which is a ratio of an actual intensity of the fluorescent X-rays originating from the inorganic components to an actual intensity of the Rayleigh scattered rays, based on each actual intensity extracted from the spectrum of the target sample, The step of determining the thickness and the content of the thin film includes: the step of substituting the estimated values ​​for variables included in the second and third arithmetic expressions to obtain an estimated fluorescent X-ray intensity ratio from a theoretical fluorescent X-ray intensity ratio, which is a ratio of a theoretical intensity of the fluorescent X-rays originating from the inorganic component to a theoretical intensity of the Rayleigh scattered rays, In the step of updating the estimate, 2. The X-ray fluorescence analysis method according to claim 1, wherein the estimated value is updated so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio and the estimated fluorescent X-ray intensity ratio converges to the measured fluorescent X-ray intensity ratio.

3. The Rayleigh scattering radiation is Rayleigh scattering radiation derived from RhKα, 2. The X-ray fluorescence analysis method according to claim 1, wherein the Compton scattered radiation is Compton scattered radiation derived from RhKα.

4. 2. The X-ray fluorescence analysis method according to claim 1, wherein the base material is mainly composed of elements having atomic numbers of 21 or less.

5. the estimated scattering intensity ratio is obtained by multiplying the theoretical scattering intensity ratio by a sensitivity coefficient ratio; The X-ray fluorescence analysis method is a step of using a bulk resin having a known content of each element as a standard sample, irradiating the standard sample with the primary X-rays, and extracting the measured intensity of the Compton scattered radiation from the spectrum of the standard sample; extracting the measured intensity of the Rayleigh scattered radiation from the spectrum of the standard sample; determining the measured scattering intensity ratio of the standard sample based on each measured intensity extracted from the spectrum of the standard sample; 2. The X-ray fluorescence analysis method according to claim 1, further comprising the step of calculating the sensitivity coefficient ratio from the theoretical scattering intensity ratio of the standard sample, which is calculated by substituting the contents of each element constituting the standard sample and a thickness of the standard sample based on the first calculation formula and the second calculation formula, and the actually measured scattering intensity ratio of the standard sample.

6. An analysis program for analyzing secondary X-rays obtained by irradiating a sample with primary X-rays from an X-ray source having a rhodium target, the program comprising: A step of extracting a measured intensity of Compton scattered radiation originating from rhodium from a spectrum of a target sample that is created based on the secondary X-rays obtained by irradiating the target sample with the primary X-rays, the target sample having a base material formed with a thin film containing a resin; Extracting the measured intensity of Rayleigh scattered radiation originating from rhodium from the spectrum of the target sample; determining a measured scattering intensity ratio, which is a ratio of the measured intensity of the Rayleigh scattered radiation to the measured intensity of the Compton scattered radiation, based on each measured intensity extracted from the spectrum of the target sample; determining a thickness of the thin film and a content of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample; the theoretical intensity of the Compton scattered radiation is calculated based on a first calculation formula having variables of the thickness of the thin film and the contents of each element constituting the target sample; the theoretical intensity of the Rayleigh scattered radiation is calculated based on a second calculation formula having variables of the thickness of the thin film and the contents of each element constituting the target sample; The step of determining the thickness and the content of the thin film includes: a step of substituting estimated values ​​for variables included in the first and second arithmetic expressions to obtain an estimated scattering intensity ratio obtained from a theoretical scattering intensity ratio which is a ratio of the theoretical intensity of the Rayleigh scattering radiation to the theoretical intensity of the Compton scattering radiation; updating the estimated scattering intensity ratio so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

7. An X-ray fluorescence analyzer, comprising: A sample stage on which a sample is placed; an X-ray tube configured to irradiate primary X-rays from an X-ray source having a rhodium target toward the sample stage; a detector for detecting secondary X-rays from the sample disposed on the sample stage; a control device for analyzing the secondary X-rays detected by the detector, The sample is a target sample having a base material on which a thin film containing a resin is formed, a theoretical intensity of Compton scattered radiation originating from rhodium contained in the secondary X-rays from the target sample is calculated based on a first calculation formula having variables of a thickness of the thin film and a content of each element constituting the target sample; a theoretical intensity of Rayleigh scattered radiation originating from rhodium contained in the secondary X-rays from the target sample is calculated based on a second calculation formula having variables of a thickness of the thin film and a content of each element constituting the target sample; The control device includes: creating an X-ray spectrum of the target sample based on the secondary X-rays; extracting the measured intensity of the Compton scattered radiation and the measured intensity of the Rayleigh scattered radiation from the created X-ray spectrum; calculating a measured scattering intensity ratio, which is a ratio of the measured intensity of the Rayleigh scattered radiation to the measured intensity of the Compton scattered radiation, based on each of the extracted measured intensities; determining a thickness of the thin film and a content of each element constituting the target sample by a fundamental parameter method based on the measured scattering intensity ratio of the target sample; The thickness of the thin film and the content of each element constituting the target sample are Substituting estimated values ​​for variables included in the first and second arithmetic expressions to obtain an estimated scattering intensity ratio obtained from a theoretical scattering intensity ratio which is a ratio of the theoretical intensity of the Rayleigh scattering radiation to the theoretical intensity of the Compton scattering radiation; The estimated scattering intensity ratio is determined by updating the estimated value so that the estimated scattering intensity ratio converges to the actually measured scattering intensity ratio.