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

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

[Technical Field]

[0001] This disclosure relates to a method for X-ray fluorescence analysis, an analysis program, and an X-ray fluorescence analyzer. [Background technology]

[0002] X-ray fluorescence analysis is an analytical method that analyzes the constituent elements of a sample by irradiating it with X-rays and measuring the fluorescent X-rays emitted from the sample. One of the analytical methods 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 elemental content of a sample by comparing the theoretical intensity, calculated using various physical constants, with the measured intensity obtained by measuring the sample. The method for calculating theoretical intensity is well-established and disclosed in Patent Document 1 and Non-Patent Document 1, among others.

[0004] Patent Document 1 discloses a method for obtaining a quantitative value of a target element by the FP method, taking into account correction for the shape of the sample, in light of the fact that the measurement intensity of fluorescent X-rays is insufficient depending on the shape of the sample. In the method disclosed in Patent Document 1, the amount of adhesion is obtained by utilizing the fact that the ratio of fluorescent X-ray intensity to scattered X-ray intensity remains constant for a certain amount of adhesion, even if the shape of the thin film sample or the fixing position of the sample changes.

[0005] Non-Patent Document 1 discloses a method for quantifying CH2O, the main component of a resin thin film coated on an iron matrix, using the fission product (FP) method. CH2O, the main component of the resin thin film, is difficult to measure using fluorescent X-rays. Therefore, in Non-Patent Document 1, the quantitative value of CH2O is estimated using RhKα Compton scattering. Furthermore, Non-Patent Document 1 describes taking the measurement intensity ratio of RhKα Compton scattering and FeKα for shape correction. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2003-107020 [Non-patent literature]

[0007] [Non-Patent Document 1] "Advances in X-ray Analysis," Agne Technical Center, 40 (2009), pp. 233-241. [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0009] However, the method disclosed in Non-Patent Document 1 corrects the shape using fluorescent X-rays derived from the main component of the base material, and assumes that the fluorescent X-rays derived from the main component of the base material can penetrate the thin film. Therefore, it could not be applied to samples using base materials with low fluorescent X-ray transmittance, such as aluminum.

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

[0011] When a bulk resin sample with sufficient thickness is used as a standard sample, X-rays that penetrate deep into the sample and are scattered cannot be detected. Because some scattered X-rays cannot be detected when bulk resin is used as a standard sample, the proportional relationship between the measured intensity of scattered rays and the theoretical intensity no longer holds. Therefore, bulk resin could not be used as a standard sample in the method disclosed in Non-Patent Document 1.

[0012] This disclosure is made to solve the aforementioned problem and provides a method for analyzing a target sample in which a thin film containing resin is formed on a base material using the FP method, with the primary objective being to broaden the scope of application of said analysis. [Means for solving the problem]

[0013] The X-ray fluorescence analysis method described herein 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 the measured intensity of rhodium-derived Compton scattered rays from the spectrum of a target sample created based on secondary X-rays obtained by irradiating a target sample, which is a thin film containing resin formed on a base material, with primary X-rays; extracting the measured intensity of rhodium-derived Rayleigh scattered rays from the spectrum of the target sample; determining the 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 each measured intensity extracted from the spectrum of the target sample; and determining the thickness of the thin film and the content of each element constituting the target sample by the fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of Compton scattered rays is determined based on a first calculation formula with 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 is determined based on a second calculation formula, where the thickness of the thin film and the content of each element constituting the sample are variables. The steps of determining the thickness and content of the thin film include substituting estimated values ​​into the variables in the first and second calculation formulas to obtain the estimated scattering intensity ratio, which is the ratio of the theoretical scattering intensity of Rayleigh scattered rays to the theoretical scattering intensity of Compton scattered rays, and updating the estimated values ​​so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0014] The analysis program of this disclosure 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 perform the following steps: extract the measured intensity of Compton scattered rays originating from rhodium from the spectrum of a target sample created based on secondary X-rays obtained by irradiating a target sample, a target sample in which a thin film containing resin is formed on a base material, with primary X-rays; extract the measured intensity of Rayleigh scattered rays originating from rhodium from the spectrum of the target sample; determine the 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 each measured intensity extracted from the spectrum of the target sample; and determine the thickness of the thin film and the content of each element constituting the target sample by the fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of Compton scattered rays is determined based on a first calculation formula with 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 is determined based on a second calculation formula, where the thickness of the thin film and the content of each element constituting the sample are variables. The steps of determining the thickness and content of the thin film include substituting estimated values ​​into the variables in the first and second calculation formulas to obtain the estimated scattering intensity ratio, which is the ratio of the theoretical scattering intensity of Rayleigh scattered rays to the theoretical scattering intensity of Compton scattered rays, and updating the estimated values ​​so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0015] The X-ray fluorescence analyzer of this disclosure includes a sample stage on which a sample is placed, an X-ray tube configured to irradiate the sample stage with primary X-rays from an X-ray source having a rhodium target, a detector for detecting secondary X-rays from a sample placed on the sample stage, and a control device for analyzing the secondary X-rays detected by the detector. The sample is a target sample in which a thin film containing resin is formed on a base material. The theoretical intensity of the rhodium-derived Compton scattered rays contained in the secondary X-rays from the target sample is determined based on a first calculation formula with the thickness of the thin film and the content of each element constituting the target sample as variables. The theoretical intensity of the rhodium-derived Rayleigh scattered rays contained in the secondary X-rays from the target sample is determined based on a second calculation formula with 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 secondary X-rays, extracts the measured intensity of Compton scattered rays and Rayleigh scattered rays from the created X-ray spectrum, and calculates the 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. 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 determined by the fundamental parameter method. The thickness of the thin film and the content of each element constituting the target sample are obtained by substituting estimated values ​​into the variables in the first and second calculation formulas to obtain the estimated scattering intensity ratio, which is 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. [Effects of the Invention]

[0016] According to this disclosure, the scope of application can be expanded when analyzing a target sample in which a thin film containing resin is formed on a base material using the FP method. [Brief explanation of the drawing]

[0017] [Figure 1] This diagram schematically shows the overall configuration of a fluorescence X-ray analyzer. [Figure 2] This is a functional block diagram of the detector and control device. [Figure 3]This figure shows an example of an X-ray spectrum stored in the spectral memory unit. [Figure 4] This is a flowchart showing the analysis method. [Figure 5] The flowchart shows a method for determining the sensitivity coefficient ratio. [Modes for carrying out the invention]

[0018] [Overall configuration of X-ray fluorescence analyzer] Figure 1 is a schematic diagram showing the overall configuration of a fluorescent X-ray analyzer. The fluorescent X-ray analyzer 10 shown in Figure 1 comprises 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 the measurement chamber 5 are enclosed by the housing 3 to be airtight, and the interior can be kept under vacuum as needed.

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

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

[0022] The measurement room 5 is equipped with a shutter 9, a primary X-ray filter 11, and a collimator 13. The shutter 9, primary X-ray filter 11, and collimator 13 are configured to slide in a direction perpendicular to the plane of the paper in Figure 1 by a drive mechanism 12.

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

[0024] The primary X-ray filter 11 is formed from a metal foil selected according to its purpose, and attenuates the background component of the primary X-rays emitted from the X-ray tube 7, thereby improving the signal-to-noise ratio of the required characteristic X-rays. In an actual apparatus, multiple primary X-ray filters 11 made of different types of metals are used, and the primary X-ray filter 11 selected according to its 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, which determines the size of the primary X-ray beam irradiating the sample S. The collimator 13 is made of an X-ray absorbing material such as brass. In the actual apparatus, multiple collimators 13 with different aperture diameters are arranged side by side in a direction perpendicular to the plane of the paper in Figure 1, and the collimator 13 selected according to the purpose is inserted onto the primary X-ray beamline by the drive mechanism 12.

[0026] An imaging unit 20 is installed at the bottom of the measurement chamber 5 to observe the measurement position of the sample S before or during measurement. Specifically, the imaging unit 20 is positioned opposite 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 imaging unit 20 on the output unit 16 and adjusts the measurement position of the sample S while viewing this image. Furthermore, when managing the X-ray fluorescence measurement results, the image data of the measurement position is used as an identifier and 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 the calculation processing unit. For example, a personal computer can be used as the control device 14. The X-ray tube 7, detector 8, operation unit 15, and output unit 16 are connected to the control device 14.

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

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

[0031] The output unit 16 includes a display device, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence). The display device displays an image according to the 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 from the control device 14 along with identification information (product name, part number, measurement location, etc.) for identifying the sample S.

[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 ROM (Read Only Memory), RAM (Random Access Memory), and SSD (Solid State Drive). An HDD (Hard Disk Drive) may be included instead of the SSD.

[0033] The ROM stores various programs, including the analysis program 143 executed by the CPU 141, and various parameters. The RAM temporarily stores data used during the execution of various programs by 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 from 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 later.

[0035] The analysis program 143 can also be provided as a program product by recording it on a computer-readable recording medium that is not temporary, such as a flexible disk, CD-ROM (Compact Disk Read Only Memory), secondary storage device, main memory, or memory card. Alternatively, the analysis program 143 can be provided by recording it on a recording medium such as a hard disk built into the computer. Furthermore, the analysis program 143 can also be provided via download over a network.

[0036] [Control device function configuration] Figure 2 is a functional block diagram of the detector and control device. The CPU 141 executes various programs to perform the operation of each functional block of the control device 14 in Figure 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 in the figures, the control device 14 also includes a control unit for controlling each of the devices constituting the X-ray fluorescence analyzer 10.

[0038] The X-ray tube 7 has a filament that emits thermionic electrons and a target T that converts the thermionic electrons into predetermined primary X-rays and emits them. 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 primary X-rays emitted from the X-ray tube 7 irradiate the sample S, secondary X-rays excited by the primary X-rays are emitted from the sample S and incident on an X-ray detector 81, such as a silicon drift detector, where they are 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. As a result, the output signal of the X-ray detector 81 becomes a stepped current pulse signal. This current pulse signal is input to the preamplifier 82 and then to a proportional amplifier 83 which includes a waveform shaping circuit, and is shaped into pulses of an appropriate shape with a pulse height corresponding to the height of each step, and then output.

[0041] The analog-to-digital converter (ADC) 106 samples this pulsed analog signal at a predetermined sampling period and digitizes it. The multi-channel analyzer (MCA) 107 discriminates each pulse according to its energy level based on the pulse height of the digitized pulse signal, counts each pulse, and creates a pulse height distribution diagram, i.e., an X-ray spectrum, which is stored in the spectral storage unit 111.

[0042] Figure 3 shows an example of an X-ray spectrum stored in the spectral storage unit 111. As shown in Figure 3, the secondary X-rays include fluorescent X-rays specific to each element contained in the sample S (FeKα, ZnKα, etc. in the figure), as well as Rayleigh scattered rays (RhKαR in the figure) and Compton scattered rays (RhKαC in the figure) reflected from 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 analyzes the X-ray spectrum obtained from the sample S using the FP method. The specific analysis method will be described below.

[0045] [Analysis method] The method for analyzing the X-ray spectrum using the data processing unit 200 will now be described. In this embodiment, the X-ray fluorescence analyzer 10 analyzes, as an example, a sample S in which a thin film F is formed on a base material B, as shown in Figure 2.

[0046] When attempting to quantify elements in a thin film, the fluorescence X-ray intensity obtained from the thin film will be lower than that obtained from a sufficiently thick bulk material. Therefore, when quantifying elements in a thin film using fluorescence X-ray analysis, the film thickness must be taken into consideration.

[0047] In this embodiment, the data processing unit 200 determines the composition of the sample S and the film thickness t of the thin film F as analysis results using the FP method.

[0048] Figure 4 is a flowchart of the analysis method. Each process (step) shown in Figure 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 irradiates the sample S with primary X-rays from the X-ray tube 7 and detects the secondary X-rays from the sample S with the detector 8, thereby acquiring an X-ray spectrum. 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, for example, the spectral lines to be extracted based on the analysis conditions input from the operation unit 15. From the operation unit 15, the substances constituting the base material B and the substances constituting the thin film F are input as analysis conditions. Note that the "substances" include at least one of compounds and elements.

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

[0053] , , , fi / R , , C , , C / R , R ,

[0055] , , , fi / R , ,

[0054] , R ,

[0056] , C / R , , , fi , , which is the intensity of Compton scattered rays.

[0052] In step S22, the control device 14 determines the measured intensity M R which is the intensity of Rayleigh scattered rays.

[0053] In step S23, the control device 14 extracts the measured intensity M fi which is the intensity of fluorescent X-rays derived from element i, for each inorganic element constituting the sample S.

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

[0055]

Equation

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

[0057]

number

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

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

[0060]

number

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

[0062] As shown in equation (3), the theoretical intensity T of Compton scattered rays C This is the content W of each element that makes up sample S. i1, W i2, ...and the theoretical intensity T is expressed by a theoretical formula with the film thickness t of the thin film F as variables. Equation (3) includes various parameters, and the control device 14 substitutes 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 being corrected in steps S9 and S10, into equation (3) to obtain the theoretical intensity TC The following is calculated. The initial value may be directly input from the operation unit 15, or it may be determined by the control device 14 based on the elements that make up the sample S. If the control device 14 determines the value based on the elements that make up the sample S, and it consists of five elements, for example, the control device 14 sets the initial value of each element to 20%. The estimated value after correction in steps S9 and S10 will be described later and will hereafter be simply referred to as the "corrected estimated value".

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

[0064]

number

[0065] Theoretical intensity T of Rayleigh scattered rays R As shown in equation (4), the theoretical intensity T of Compton scattered rays is C Similarly, it can be expressed as a theoretical formula with the content of each element constituting the sample S and the thickness t of the thin film F as variables. The control device 14 substitutes the 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 equation (4) to obtain the theoretical intensity T of Rayleigh scattered rays. R Calculate.

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

[0067]

number

[0068] T fi This is the theoretical intensity of the fluorescent X-rays originating from element i. As shown in equation (5), the theoretical intensity T of the fluorescent X-rays originating from element i fiThis is expressed by a theoretical formula in which the film thickness t and the content of element i are variables. The control device 14 substitutes the 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) to obtain the theoretical intensity T of the fluorescent X-rays originating from element i. fi Calculate.

[0069] Furthermore, since the mechanisms of Compton scattering, Rayleigh scattering, and fluorescence X-ray generation from each element are different, equations (3) to (5) are distinct from each other. Also, the theoretical formulas for equations (3) to (5) are based on the respective spectral line generation mechanisms and are publicly known. Therefore, a detailed explanation of equations (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]

number

[0072] k C / R This is the sensitivity coefficient ratio, where k is the sensitivity coefficient for Compton scattering. C The sensitivity coefficient k of Rayleigh scattered rays for this purpose. R This is the ratio of the sensitivity coefficient ratio k. C / R This is obtained by measuring a standard sample with a known composition ratio and is stored in the parameter storage unit 112. Sensitivity coefficient ratio k C / R The specific calculation method will be explained later, referring to Figure 5.

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

[0074]

number

[0075] k fi / R This is the sensitivity coefficient ratio of fluorescent X-rays derived from element i, where k is the sensitivity coefficient of fluorescent X-rays derived from element i. fi The sensitivity coefficient k of Rayleigh scattered rays for this purpose. R This is the ratio of the sensitivity coefficient ratio k. fi / R This is obtained by measuring a standard sample containing element i and with known content of each element, and is stored in the parameter storage unit 112. Sensitivity coefficient ratio k fi / R The specific calculation method will be explained later, referring to Figure 5.

[0076] In step S8, the control device 14 determines the estimated scattering intensity ratio E C / R The measured scattering intensity ratio M C / R It converges to, and the estimated X-ray fluorescence intensity ratio E fi / R The measured X-ray fluorescence intensity ratio M fi / R It determines whether or not it has converged to the estimated scattering intensity ratio E. For example, the control device 14 determines whether or not it has converged to the estimated scattering intensity ratio E. C / R and the measured scattering intensity ratio M C / R The difference between the two is smaller than a predetermined first threshold, and the estimated X-ray fluorescence intensity ratio E fi / R and the measured fluorescence X-ray intensity ratio M fi / R Convergence is determined when the difference between the first and second thresholds is smaller than a predetermined second threshold. The first and second thresholds may be predetermined and, for example, determined based on the required precision.

[0077] The method for determining convergence is not limited to the method described above. 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.

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

[0079] In step S9, the control device 14 determines the content W of each element. i1, W i2...The estimated intensity ratio is modified so that it converges to the measured intensity ratio.

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

[0081] In steps S5 to S7, the control device 14 adjusts the content W of each element that was corrected in steps S9 and S10. i1, W i2 ...and substitute the film thickness t into equations (3) to (5) above to obtain the theoretical strength T C ,T R ,T fi To find the estimated scattering intensity ratio E C / R , and estimated X-ray fluorescence intensity ratio E fi / R We seek.

[0082] The control device 14 repeats steps S9, S10, and steps S5 to S7 until convergence occurs.

[0083] If convergence is determined (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 when convergence occurs. C / R , and estimated X-ray fluorescence intensity ratio E fi / R The content of each element W i1 ,W i2 ...and the film thickness t is 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 were identified by input from the operation unit 15, but they may also be identified by qualitative analysis of the obtained spectrum.

[0085] [Method for determining the sensitivity coefficient ratio] Figure 5 is a flowchart showing the method for determining the sensitivity coefficient ratio. C / RThis is determined from the X-ray spectrum of a standard sample with known elemental content. The sensitivity coefficient ratio k fi / R This is determined from the X-ray spectrum of a standard sample containing the inorganic elements present in the sample to be analyzed, and whose content of each element is known. Each process (step) shown in Figure 5 is performed by the control device 14, and is realized by the CPU 141 executing various programs, including the analysis program 143. Below, as an example, the sensitivity coefficient ratio k is used. C / R And, the sensitivity coefficient ratio k of lead fPb / R The sensitivity coefficient ratio k of iron fFe / R The goal is to find the following:

[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 The sensitivity coefficient ratio k of lead was determined from the X-ray spectrum of the first standard sample. fPb / R The sensitivity coefficient ratio k of iron fFe / R This shall be 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 content. The second standard sample is a bulk metal containing lead and iron, with known content of each element. Note that the bulk resin and bulk metal each only need to have a thickness such that film thickness does not need to be considered in the FP method.

[0087] First, the control device 14 performs steps S110 to step S By performing step 150, the sensitivity coefficient ratio k is obtained from the X-ray spectrum of the first standard sample. C / R To determine this, 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 measures the actual intensity M, which is the intensity of Compton scattered radiation.C The control device 14 extracts the measured intensity M of Compton scattered rays from the X-ray spectrum of the first standard sample. C Extract it.

[0090] In step S122, the control device 14 measures the measured intensity M, which is the intensity of Rayleigh scattered rays. R The control device 14 extracts the measured intensity M of Rayleigh scattered rays from the X-ray spectrum of the first standard sample. R Extract it.

[0091] In step S130, the control device 14 uses the measured intensity M extracted in steps S121 and S122. C and measured intensity M R Therefore, based on the above equation (1), the measured scattering intensity ratio M C / R We seek.

[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 Compton scattered rays for the first standard sample based on equation (3) described above. C The theoretical strength T is calculated by assuming that the film thickness t is infinite or a sufficiently large value. C The following is calculated. If 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 Rayleigh scattered rays for the first standard sample based on equation (4) described above. R The following is calculated. The film thickness t is set to infinity or a 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 adds the measured scattering intensity ratio M calculated in steps S130 and S140 to the following equation (8). C / R Theoretical intensity T of Compton scattered rays C , and the theoretical intensity T of Rayleigh scattered rays R By substituting this, the sensitivity coefficient ratio k C / R Calculate.

[0096]

number

[0097] Next, the control device 14 performs steps S160 to S200 to obtain the sensitivity coefficient ratio of lead from the X-ray spectrum of the second standard sample k fPb / R The sensitivity coefficient ratio k of iron fFe / R The following is determined. 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 measures the actual intensity M, which is the intensity of fluorescent X-rays originating from each inorganic element. fi Each of these is extracted. More specifically, the control device 14 extracts the measured intensity M of lead-derived fluorescent X-rays from the X-ray spectrum of the second standard sample. fPb The measured intensity of X-ray fluorescence derived from iron M fFe Extract and.

[0100] In step S172, the control device 14 measures the measured intensity M, which is the intensity of Rayleigh scattered rays. R The control device 14 extracts the measured intensity M of Rayleigh scattered rays from the X-ray spectrum of the second standard sample. R Extract it.

[0101] In step S180, the control device 14 determines the measured fluorescence X-ray intensity M from the element i extracted in steps S171 and S172 fi and the measured Rayleigh scattering line intensity M R to obtain the measured fluorescence X-ray intensity ratio M fi / R based on the above formula (2). More specifically, the control device 14 determines the measured fluorescence X-ray intensity ratio M of lead fPb / R and the measured fluorescence X-ray intensity ratio M of iron fFe / R .

[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 fluorescence X-ray from each inorganic element fi based on the above formula (5). More specifically, in the present embodiment, the control device 14 determines the theoretical intensity T of the fluorescence X-ray from lead fPb and the theoretical intensity T of the fluorescence X-ray from iron fFe for the second standard sample. The film thickness t is set to infinity or an appropriate sufficiently large value as in step S141. When the standard sample is a thin film, the control device 14 substitutes the film thickness of the thin film into formula (5).

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

[0105] In step S200, the control device 14 substitutes the measured fluorescence X-ray intensity ratio M fi / R calculated in steps S180 and S190, the theoretical intensity T of the fluorescence X-ray fi , and the theoretical intensity T of the Rayleigh scattering line RBy substituting this, the sensitivity coefficient ratio k of fluorescent X-rays can be obtained. fi / R This calculates the sensitivity coefficient ratio k of lead. More specifically, the sensitivity coefficient ratio k of lead. fPb / R This is the measured X-ray fluorescence intensity ratio of lead M fPb / R The theoretical strength of lead T fPb , and the theoretical intensity T of Rayleigh scattered rays R The sensitivity coefficient ratio k of iron can be obtained by substituting it into equation (9). fFe / R This is the measured X-ray fluorescence intensity ratio of iron M fFe / R The theoretical strength of iron T fFe , and the theoretical intensity T of Rayleigh scattered rays R This can be found by substituting into equation (9).

[0106]

number

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

[0108] In Figure 5, 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 determined the sensitivity coefficient ratio k from the X-ray spectrum of the second standard sample, which is a bulk metal. C / R The sensitivity coefficient ratio may be determined using a standard sample consisting of components similar to the target sample being measured, but it may also be determined using a standard sample consisting of components different from the target sample.

[0109] [Examples and Comparative Examples] The accuracy of the analytical values ​​obtained by the analytical method according to this embodiment was investigated. Sample S is a paperclip coated with resin. The base material is iron (Fe), and the resin is polyethylene (C2H4). Table 1 shows the analytical results and analytical conditions for quantitative analysis of lead (Pb) in the resin coating of sample S, performed according to the analytical method according to this embodiment and the calibration curve method.

[0110] [Table 1]

[0111] In the example, quantitative analysis of lead in the resin coating of sample S was performed according to the analytical method of this embodiment. In the example, the X-ray spectrum obtained by placing sample S on sample stage 2 without destroying it was analyzed according to the analytical method shown in Figure 4. The sensitivity coefficient ratios were determined using bulk polyethylene, iron, and lead as standard samples by the method shown in Figure 5.

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

[0113] Here, the calibration curve method in Comparative Examples 1 and 2 is a quantitative analysis technique that draws a calibration curve based on the correlation between the intensity of lead-derived fluorescent X-rays in the X-ray spectrum obtained by measuring standard samples with known lead content and the lead content. In addition, in the calibration curve method in Comparative Examples 1 and 2, a known method is used to correct for the effect of sample shape by creating a calibration curve based on the intensity ratio of the measured intensity of lead fluorescent X-rays and the continuous scattered X-rays near the lead fluorescent X-rays.

[0114] In Comparative Example 1, the lead analysis value was lower compared to analysis using other methods because the analysis was performed without separating the base material and the thin film. This is because, although shape correction was performed in Comparative Example 1, the calibration curve method cannot measure the thickness of the thin film, and therefore the results were 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. Therefore, the film thickness was corrected as part of the shape. As a result, the analytical value was higher in Comparative Example 2 compared to Comparative Example 1.

[0116] Thus, with the calibration curve method, by separating the base material and the thin film and measuring only the thin film, highly accurate analytical results can be obtained.

[0117] The analytical results in the example were similar to those in Comparative Example 2. That is, by using the analytical method according to this embodiment, the target component in the resin thin film can be identified without destroying the sample S. accuracy It can measure accurately.

[0118] [Effects of using scattering intensity ratios] As shown in Table 1, the analytical method according to this embodiment allows for the measurement of the target component in a resin thin film without destroying the sample S. Therefore, the analytical method according to this embodiment can also be applied to samples that cannot be destroyed, such as those that will be shipped as products or incorporated into products after measurement.

[0119] Furthermore, in the analytical method according to this embodiment, the ratio of the intensity of Rayleigh scattered rays to the intensity of Compton scattered rays is used. By normalizing the intensity of Compton scattered rays by the intensity of Rayleigh scattered rays, the influence of the shape of the sample S on the quantitative value can be corrected.

[0120] As a comparative example, if normalization is performed using fluorescent X-rays derived from the base material, this method cannot be used if the transmittance of the fluorescent X-rays is low to the thin film, as the fluorescent X-rays cannot be detected. In particular, if the main component of the base material B of sample S is a light element with an atomic number of 21 (scandium) or lower, the fluorescent X-rays of that element have low energy and are difficult to penetrate the thin film, making them difficult to detect with the fluorescent X-ray 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, since normalization is performed by the intensity of Rayleigh scattered rays, it is possible to analyze sample S on which a resin thin film has been formed, regardless of the base material of sample S, thereby expanding the scope of application of analysis using the FP method. In other words, according to the method of this embodiment, it is possible to analyze samples containing a base material mainly composed of light elements with an atomic number of 21 or lower.

[0121] Furthermore, in this embodiment, by using the ratio of the intensity of Rayleigh scattered rays to the intensity of Compton scattered rays, bulk resin, which is a block of resin, can be used as a standard sample. The reason for this will be explained below.

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

[0123] Therefore, when bulk resin is used as a standard sample, the intensity of scattered radiation I2 from primary X-rays that penetrate deep into sample S cannot be detected. As a result, the proportional relationship between the measured intensity of scattered radiation and the theoretical intensity is disrupted, and the sensitivity coefficient cannot be determined.

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

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

[0126] In the above embodiment, the analysis was performed using Compton and Rayleigh scattered rays originating from RhKα. However, if sufficient intensity can be obtained, the same FP method analysis can be performed using Compton and Rayleigh scattered rays originating from RhKβ.

[0127] Furthermore, in the above embodiment, the control device 14 controls the theoretical intensity T of Compton scattered rays.C And the theoretical intensity T of Rayleigh scattered rays R After calculating each of them, the estimated scattering intensity ratio E C / R The theoretical intensity T of Compton scattered rays was calculated. C And the theoretical intensity T of Rayleigh scattered rays R Without calculating each of them separately, the estimated scattering intensity ratio E C / R You may calculate this.

[0128] [Pattern] Those skilled in the art will understand that the embodiments described above are specific examples of the following embodiments.

[0129] (Section 1) One embodiment of the X-ray fluorescence analysis method is an X-ray fluorescence analysis method that 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 the measured intensity of Compton scattered rays originating from rhodium from the spectrum of a target sample created based on secondary X-rays obtained by irradiating a target sample, which is a thin film containing resin formed on a base material, with primary X-rays; extracting the measured intensity of Rayleigh scattered rays originating from rhodium from the spectrum of the target sample; determining the 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 each measured intensity extracted from the spectrum of the target sample; and determining the thickness of the thin film and the content of each element constituting the target sample by the fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of Compton scattered rays is determined based on a first calculation formula with 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 is determined based on a second calculation formula, where the thickness of the thin film and the content of each element constituting the sample are variables. The steps of determining the thickness and content of the thin film include substituting estimated values ​​into the variables in the first and second calculation formulas to obtain the estimated scattering intensity ratio, which is the ratio of the theoretical scattering intensity of Rayleigh scattered rays to the theoretical scattering intensity of Compton scattered rays, and updating the estimated values ​​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 Section 1, the application range of analysis by the FP method can be expanded by using the scattering intensity ratio. More specifically, even for samples in which a resin thin film is formed on a matrix material mainly composed of elements that are difficult to measure by X-ray fluorescence, analysis by the FP method can be performed without destroying the sample. Furthermore, because primary X-rays penetrate deep into the resin component, scattered radiation that has penetrated deep and bounced back may not be detectable. Even in this case, the influence of undetectable scattered radiation can be canceled out by using the scattering intensity ratio, so bulk resin can be used as a standard sample. Therefore, even when it is difficult to prepare a standard sample of a thin film, analysis by the FP method can be performed.

[0131] (Section 2) In the X-ray fluorescence analysis method described in Section 1, the thin film contains at least one inorganic component. The theoretical intensity of X-ray fluorescence derived from the inorganic component is determined based on a third calculation formula with 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 X-ray fluorescence derived from the inorganic component from the spectrum of the target sample and extracting the measured X-ray fluorescence intensity, which is the measured intensity of X-ray fluorescence derived from the inorganic component; and determining the measured X-ray fluorescence intensity ratio, which is the ratio of the measured intensity of Rayleigh scattered rays to the measured intensity of X-ray fluorescence derived from the inorganic component, based on each measured intensity extracted from the spectrum of the target sample. The step of determining the thickness and content of the thin film further includes the step of substituting estimated values ​​into the variables included in the second and third calculation formulas to determine the estimated X-ray fluorescence intensity ratio from the theoretical X-ray fluorescence intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered rays to the theoretical intensity of X-ray fluorescence derived from the inorganic component. 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 X-ray fluorescence intensity ratio converges to the measured X-ray fluorescence intensity ratio.

[0132] According to the X-ray fluorescence analysis method described in paragraph 2, the content of inorganic components in the thin film resin can be determined.

[0133] (Section 3) In the X-ray fluorescence analysis method described in Section 1 or 2, Rayleigh scattered rays are Rayleigh scattered rays originating from RhKα. Compton scattered rays are derived from RhKα. Compton scattered rays That is the case.

[0134] According to the X-ray fluorescence analysis method described in Section 3, the accuracy of the analysis can be improved by using scattered radiation originating from RhKα, which has a higher intensity than RhKβ.

[0135] (Article 4) In the fluorescent X-ray analysis method described in any one of Articles 1 to 3, the base material shall be mainly composed of light elements with atomic numbers of 21 or less.

[0136] According to the X-ray fluorescence analysis method described in Section 4, the FP method can be applied even to samples in which a resin thin film is formed on a matrix material whose main component is an element that is difficult to measure using X-ray fluorescence.

[0137] (Article 5) In the X-ray fluorescence analysis method described in any one of Articles 1 to 4, the estimated scattering intensity ratio is obtained 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 with known content of each element as a standard sample; extracting the measured intensity of Compton scattered rays from the spectrum of a standard sample obtained by irradiating the standard sample with primary X-rays; extracting the measured intensity 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 obtained by substituting the content of each element constituting the standard sample and the thickness of the standard sample based on the first and second calculation formulas, and the measured scattering intensity ratio of the standard sample.

[0138] According to the X-ray fluorescence analysis method described in Section 5, analysis by the FP method can be performed even when it is difficult to prepare standard samples of thin films.

[0139] (Section 6) An analysis program according to one embodiment 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 perform the following steps: extract the measured intensity of Compton scattered rays originating from rhodium from the spectrum of a target sample created based on secondary X-rays obtained by irradiating a target sample, a target sample in which a thin film containing resin is formed on a base material, with primary X-rays; extract the measured intensity of Rayleigh scattered rays originating from rhodium from the spectrum of the target sample; determine the 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 each measured intensity extracted from the spectrum of the target sample; and determine the thickness of the thin film and the content of each element constituting the target sample by the fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of Compton scattered rays is determined based on a first calculation formula with 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 is determined based on a second calculation formula, where the thickness of the thin film and the content of each element constituting the sample are variables. The steps of determining the thickness and content of the thin film include substituting estimated values ​​into the variables in the first and second calculation formulas to obtain the estimated scattering intensity ratio, which is the ratio of the theoretical scattering intensity of Rayleigh scattered rays to the theoretical scattering intensity of Compton scattered rays, and updating the estimated values ​​so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

[0140] (Section 7) A fluorescent X-ray analyzer according to one embodiment includes a sample stage on which a sample is placed, an X-ray tube configured to irradiate the sample stage with primary X-rays from an X-ray source having a rhodium target, a detector for detecting secondary X-rays from a sample placed on the sample stage, and a control device for analyzing the secondary X-rays detected by the detector. The sample is a target sample in which a thin film containing resin is formed on a base material. The theoretical intensity of the rhodium-derived Compton scattered rays contained in the secondary X-rays from the target sample is determined based on a first calculation formula in which the thickness of the thin film and the content of each element constituting the target sample are variables. The theoretical intensity of the rhodium-derived Rayleigh scattered rays contained in the secondary X-rays from the target sample is determined based on a second calculation formula in which the thickness of the thin film and the content of each element constituting the target sample are variables. The control device creates an X-ray spectrum of the target sample based on secondary X-rays, extracts the measured intensity of Compton scattered rays and Rayleigh scattered rays from the created X-ray spectrum, and calculates the 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. 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 determined by the fundamental parameter method. The thickness of the thin film and the content of each element constituting the target sample are obtained by substituting estimated values ​​into the variables in the first and second calculation formulas to obtain the estimated scattering intensity ratio, which is 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 Section 6 and the X-ray fluorescence analyzer described in Section 7, the application range of analysis by the FP method can be expanded by using the scattering intensity ratio. More specifically, even for samples in which a resin thin film is formed on a matrix material mainly composed of elements that are difficult to measure by X-ray fluorescence, analysis by the FP method can be performed without destroying the sample. Furthermore, because primary X-rays penetrate deep into the resin component, there are cases where scattered radiation that has penetrated deep and bounced back cannot be detected. Even in this case, by using the scattering intensity ratio, the influence of undetectable scattered radiation can be canceled out, so bulk resin can be used as a standard sample. Therefore, even when it is difficult to prepare a standard sample of a thin film, analysis by the FP method can be performed.

[0142] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of symbols]

[0143] 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. A fluorescence X-ray analysis 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 steps include: extracting the measured intensity of rhodium-derived Compton scattered rays from the spectrum of the target sample, which is created based on the secondary X-rays obtained by irradiating the target sample, on a base material in which a thin film containing resin is formed, with the primary X-rays; The steps include extracting the measured intensity of Rayleigh scattered rays originating from rhodium from the spectrum of the aforementioned sample, The steps include determining the 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, The method includes the step of determining the thickness of the thin film and the content of each element constituting the target sample by the fundamental parameter method based on the measured scattering intensity ratio of the target sample. The theoretical intensity of the Compton scattered rays is determined based on a first calculation formula in which the thickness of the thin film and the content of each element constituting the sample are variables. The theoretical intensity of the Rayleigh scattered rays is determined based on a second calculation formula in which the thickness of the thin film and the content of each element constituting the sample are variables. The step of determining the thickness of the thin film and the content is as follows: The steps include substituting estimated values ​​into the variables included in the first and second calculation formulas to obtain an estimated scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered rays to the theoretical intensity of Compton scattered rays, A method for analyzing X-ray fluorescence, comprising the step of 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, The theoretical intensity of the fluorescent X-rays derived from the inorganic component is determined based on a third calculation formula in which the thickness of the thin film and the content of the inorganic component are variables. The steps include detecting spectral lines from the target sample due to fluorescent X-rays originating from the inorganic component, and extracting the measured fluorescent X-ray intensity, which is the measured intensity of the fluorescent X-rays originating from the inorganic component, The method further includes the step of determining the measured fluorescent X-ray intensity ratio, which is the ratio of the measured intensity of Rayleigh scattered rays to the measured intensity of fluorescent X-rays derived from the inorganic component, based on the measured intensities extracted from the spectrum of the target sample, The step of determining the thickness of the thin film and the content is as follows: The process further includes the step of substituting the estimated values ​​into the variables included in the second and third calculation formulas to obtain the estimated fluorescent X-ray intensity ratio from the theoretical fluorescent X-ray intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered rays to the theoretical intensity of fluorescent X-rays originating from the inorganic component, In the step of updating the estimated value, The fluorescent X-ray analysis method according to claim 1, wherein the estimated values ​​are updated such 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 aforementioned Rayleigh scattered rays are Rayleigh scattered rays originating from RhKα, The fluorescent X-ray analysis method according to claim 1, wherein the Compton scattered radiation is Compton scattered radiation originating from RhKα.

4. The fluorescent X-ray analysis method according to claim 1, wherein the base material mainly consists of elements with atomic numbers 21 or lower.

5. The estimated scattering intensity ratio is obtained by multiplying the theoretical scattering intensity ratio by the sensitivity coefficient ratio. X-ray fluorescence analysis method: A bulk resin with known elemental content is used as a standard sample, and the measured intensity of the Compton scattered rays is extracted from the spectrum of the standard sample obtained by irradiating the standard sample with the primary X-rays. The steps include extracting the measured intensity of the Rayleigh scattered rays from the spectrum of the standard sample, The steps include determining the measured scattering intensity ratio of the standard sample based on each measured intensity extracted from the spectrum of the standard sample, The fluorescent X-ray analysis method according to claim 1, further comprising the step of determining the sensitivity coefficient ratio from the theoretical scattering intensity ratio of the standard sample, which is obtained by substituting the content of each element constituting the standard sample and the thickness of the standard sample based on the first calculation formula and the second calculation formula, and the 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, wherein the computer... The steps include: extracting the measured intensity of rhodium-derived Compton scattered rays from the spectrum of the target sample, which is created based on the secondary X-rays obtained by irradiating the target sample, on a base material in which a thin film containing resin is formed, with the primary X-rays; The steps include extracting the measured intensity of Rayleigh scattered rays originating from rhodium from the spectrum of the aforementioned sample, The steps include determining the 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, 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 determined by the fundamental parameter method. The theoretical intensity of the Compton scattered rays is determined based on a first calculation formula in which the thickness of the thin film and the content of each element constituting the sample are variables. The theoretical intensity of the Rayleigh scattered rays is determined based on a second calculation formula in which the thickness of the thin film and the content of each element constituting the sample are variables. The step of determining the thickness of the thin film and the content is as follows: The steps include substituting estimated values ​​into the variables included in the first and second calculation formulas to obtain an estimated scattering intensity ratio, which is the ratio of the theoretical intensity of Rayleigh scattered rays to the theoretical intensity of Compton scattered rays, An analysis program comprising the step of updating the estimated value so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

7. X-ray fluorescence analyzer, A sample stand on which the sample is placed, An X-ray tube configured to irradiate the sample stage with primary X-rays from an X-ray source having a rhodium target, A detector for detecting secondary X-rays from the sample placed on the sample stage, The system includes a control device that analyzes the secondary X-rays detected by the detector, The aforementioned sample is a target sample in which a thin film containing resin is formed on a base material. The theoretical intensity of the rhodium-derived Compton scattered radiation contained in the secondary X-rays from the target sample is determined based on a first calculation formula in which the thickness of the thin film and the content of each element constituting the target sample are variables. The theoretical intensity of Rayleigh scattered rays originating from rhodium, contained in the secondary X-rays from the target sample, is determined based on a second calculation formula in which the thickness of the thin film and the content of each element constituting the target sample are variables. The control device is Based on the secondary X-rays, an X-ray spectrum of the target sample is prepared. From the created X-ray spectrum, the measured intensity of the Compton scattered rays and the measured intensity of the Rayleigh scattered rays are extracted. Based on the extracted measured intensities, the measured scattering intensity ratio, which is the ratio of the measured intensity of Rayleigh scattered rays to the measured intensity of Compton scattered rays, is determined. 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 determined by the fundamental parameter method. The thickness of the thin film and the content of each element constituting the sample are as follows: By substituting estimated values ​​into the variables included in the first and second calculation formulas, the estimated scattering intensity ratio is obtained from the theoretical scattering intensity ratio, which is the ratio of the theoretical intensity of the Rayleigh scattered rays to the theoretical intensity of the Compton scattered rays. A fluorescence X-ray analyzer, which is obtained by updating the estimated value so that the estimated scattering intensity ratio converges to the measured scattering intensity ratio.

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