JP6467684B2 - X-ray fluorescence analyzer - Google Patents

Description

  The present invention relates to an X-ray fluorescence analyzer for determining the composition of a sample whose measurement surface is covered with a film.

  Conventionally, in a fluorescent X-ray analysis, for a liquid sample or a powder sample that is scattered in a vacuum as it is, the measurement surface is covered with a film, and the sample is irradiated with primary X-rays through the film, The intensity of the generated fluorescent X-ray is measured through a film. Since X-rays are attenuated (absorbed) when passing through the film, some correction is necessary for accurate analysis. For example, as a conventional technique, there is a fluorescent X-ray analysis method as described below. (See Patent Document 1).

  In this fluorescent X-ray analysis method, first, for a plurality of standard samples whose main constituent elements are known and different from each other, in a first measurement condition in which the sample surface (measurement surface) is exposed in a vacuum, in an inert gas atmosphere In the second measurement condition in which the sample surface is exposed and in the third measurement condition in which the sample surface is covered with a protective film (film) in a vacuum, the main X The intensity of fluorescent X-rays generated from the constituent elements is measured. Then, for each fluorescent X-ray, the attenuation rate of the fluorescent X-ray intensity under the second and third measurement conditions with respect to the fluorescent X-ray intensity under the first measurement condition is calculated, and those attenuation rates are stored. Keep it.

  Next, the intensity of fluorescent X-rays generated by irradiating primary X-rays with respect to an analysis target sample with unknown constituent element content, ie, an unknown sample, is measured, and the intensity is unknown for each fluorescent X-ray. Correction is performed by the attenuation rate according to the measurement condition of the sample. For example, when an unknown sample whose measurement surface is covered with a film is measured in a vacuum, the attenuation rate of the intensity of the fluorescent X-rays in the third measurement condition relative to the intensity of the fluorescent X-rays in the first measurement condition Correct by.

JP-A-8-105849

  However, the attenuation rate of X-rays by the film varies depending on the composition and thickness of the film and the wavelength of the X-ray, and not only fluorescent X-rays but also primary X-rays are attenuated when passing through the film. In order to accurately analyze the unknown sample with the measurement surface covered by the above-described conventional technique, a film having the same composition and thickness as used for measurement of the unknown sample and a primary X-ray having the same wavelength distribution are used in advance. It is necessary to measure the standard sample and calculate and store the attenuation rate for each fluorescent X-ray. Since there are a wide variety of films and primary X-rays may be switched and used depending on an unknown sample, calculating and storing all of the assumed attenuation factors is time consuming and impractical.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a fluorescent X-ray analyzer that can easily and accurately determine the composition of a sample whose measurement surface is covered with a film.

  In order to achieve the above object, an X-ray fluorescence analyzer of the present invention first comprises an X-ray source that irradiates a sample with primary X-rays, and a detection means that measures the intensity of the fluorescent X-rays generated from the sample. , Storing the measured intensity measured by the detection means for the sample, and calculating the theoretical intensity of fluorescent X-rays generated from the sample excited by the primary X-ray based on the assumed composition for the sample; Calculate the composition of the sample by successively correcting the assumed composition for the sample so that the theoretical intensity matches the measured measured intensity stored for the sample converted to the theoretical intensity scale. And a monitor sample whose composition is calculated and stored in the calculation means, and an input means for inputting the composition of the film when the measurement surface of the sample is covered with the film. To have.

  And the said calculation means memorize | stores the measurement intensity | strength measured with the said detection means about the said monitor sample with which the measurement surface was covered with the said film, the composition memorize | stored about the said monitor sample, the composition input about the said film, and the said film Based on the thickness assumed for the film, the theoretical intensity of fluorescent X-rays generated by the monitor sample and attenuated by the film excited by primary X-rays attenuated by the film is calculated. The thickness assumed for the film is successively approximated and corrected so that the measured intensity stored for the monitor sample covered with the measurement surface matches the converted measured intensity converted to a theoretical intensity scale, and the film Is calculated and stored.

  The calculation means further stores the measurement intensity measured by the detection means for an unknown sample whose composition is covered with the film and whose measurement surface is unknown, the composition assumed for the unknown sample, and the composition input for the film And calculating the theoretical intensity of fluorescent X-rays that are excited by the primary X-rays attenuated by the film and generated from the unknown sample and attenuated by the film, based on the memorized thickness for the film, The composition assumed for the unknown sample is successively approximated and corrected so that the measured intensity stored for the unknown sample whose measurement surface is covered with the film matches the converted measurement intensity converted to the theoretical intensity scale. The composition of the unknown sample is calculated.

  The fluorescent X-ray analyzer of the present invention includes a calculation means for calculating the composition of a sample by a fundamental parameter method (hereinafter also referred to as FP method). The calculation means is first used for measuring an unknown sample. Using the measured intensity of a monitor sample whose composition is covered with the measurement surface of the film, not only the attenuation of the fluorescent X-ray film but also the attenuation of the primary X-ray film is incorporated into the theoretical intensity calculation. The film thickness is calculated and stored by the FP method. At this time, the work to be performed by the measurer is only the input of the composition of the film and the measurement of the monitor sample whose measurement surface is covered with the film. The calculation means uses the measured intensity of the unknown sample whose measurement surface is covered with the film, and based on the composition input and the stored thickness for the film, not only the attenuation of the fluorescent X-rays but also the primary. The composition of the unknown sample is calculated by the FP method in which attenuation by X-ray film is also incorporated in the theoretical intensity calculation.

  In other words, even if the composition of the film used for the measurement of the unknown sample changes or the primary X-ray used for the measurement of the unknown sample is switched, the work to be performed in advance by the measurer is the input of the film composition. It is only a measurement of a monitor sample whose measurement surface is covered with a film, and, as in the prior art, using a film having the same composition and thickness as used for measurement of an unknown sample and a primary X-ray having the same wavelength distribution. Measure the standard sample both when the measurement surface is exposed and when it is covered with film, and calculate and store the attenuation factor for each fluorescent X-ray. .

  Moreover, in the fluorescent X-ray analyzer of the present invention, not only the attenuation of the fluorescent X-ray by the film but also the primary is calculated both when the thickness of the film is calculated in advance and when the composition of the unknown sample is calculated based on the thickness. The attenuation by X-ray film is also based on the FP method incorporated in the theoretical intensity calculation. Therefore, according to the fluorescent X-ray analyzer of the present invention, it is possible to easily and accurately determine the composition of an unknown sample whose measurement surface is covered with a film.

  In the X-ray fluorescence analyzer of the present invention, it is preferable that the calculation means has the following configuration. That is, in calculating the thickness of the film, the calculating means first calculates fluorescence X generated from each component in the monitor sample excited by the primary X-ray based on the composition stored for the monitor sample. Calculating the theoretical intensity of the measurement line, which is a line, as the theoretical intensity without film for each measurement line, and based on the composition stored for the monitor sample, the composition input for the film and the assumed thickness for the film, The theoretical intensity of each measurement line excited by the primary X-ray attenuated by the film and generated from the monitor sample and attenuated by the film is calculated as the theoretical intensity with film of each measurement line.

  The calculating means calculates the attenuation rate by the film in each measurement line based on the theoretical strength without film and the theoretical strength with film of each measurement line, and calculates the theoretical strength with film of each measurement line. Based on this, the standard deviation and the variation coefficient in each measurement line are calculated, and the measurement line having the smallest product of the attenuation factor and the variation coefficient is selected as the optimum measurement line.

  Further, the calculation means stores the measurement intensity of the optimum measurement line measured by the detection means for the monitor sample whose measurement surface is covered with the film, and is input for the composition and the film stored for the monitor sample. And the monitor sample excited by the primary X-ray attenuated by the film based on the thickness assumed for the film having the initial value of the composition and the thickness assumed when the theoretical strength with the film was calculated. The theoretical intensity of the optimum measurement line that is generated from and attenuated by the film is calculated, and the theoretical intensity and the measured intensity of the optimum measurement line stored for the monitor sample whose measurement surface is covered with the film are calculated as a theoretical intensity scale. The thickness assumed for the film is corrected to be approximated so that the converted measured intensity converted to Te stores to calculate the thickness of the film.

  In this case, the calculation means incorporates not only the attenuation of the fluorescent X-ray film but also the attenuation of the primary X-ray film into the theoretical intensity calculation for the monitor sample. Calculates the theoretical strength, and based on them, selects the optimum measurement line for measuring a monitor sample whose measurement surface is covered with a film, so that the film thickness can be calculated more accurately and based on it. In addition, the composition of the unknown sample can be calculated, and the labor of the measurer does not increase.

  In the fluorescent X-ray analyzer of the present invention, the calculation means further calculates the thickness of the film and the calculated thickness of the film and the thickness assumed when the theoretical strength with the film is calculated. It is preferable to repeat the calculation from the theoretical strength with film to the calculation of the thickness of the film, assuming that the calculated thickness of the film is the thickness assumed for the film until the difference falls within a predetermined range. In this case, the calculation means reselects the optimum measurement line until the difference between the calculated film thickness and the thickness assumed when the theoretical strength with film is calculated falls within a predetermined range. Since the thickness is repeatedly calculated, the thickness of the film can be calculated more accurately, the composition of the unknown sample can be calculated more accurately based on the thickness, and the labor of the measurer does not increase.

It is the schematic which shows the fluorescent X-ray-analysis apparatus of the 1st-3rd embodiment of this invention. It is a flowchart of operation | movement of the fluorescent X ray analysis apparatus of 1st Embodiment. It is a flowchart of operation | movement of the fluorescent X-ray-analysis apparatus of 2nd Embodiment. It is a flowchart of operation | movement of the fluorescent X-ray-analysis apparatus of 3rd Embodiment.

  The X-ray fluorescence analyzer according to the first embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this apparatus first has an X-ray source 1 such as an X-ray tube that irradiates samples 3 and 13 with primary X-rays 2, and the intensity of fluorescent X-rays 4 generated from the samples 3 and 13. Detection means 9 that measures the composition, calculation means 10A such as a computer that calculates the composition of samples 3 and 13, monitor sample 3 in which the composition is calculated and stored in calculation means 10A, and the measurement surfaces of samples 3 and 13 are films 12 is provided with an input means 11 such as a keyboard and a touch panel for inputting the composition of the film 12 when covered with the film 12.

  The calculation means 10A stores the measured intensities measured by the detection means 9 for the samples 3 and 13, and is generated from the samples 3 and 13 by being excited by the primary X-ray 2 based on the assumed composition for the samples 3 and 13. The theoretical intensity of the fluorescent X-ray 4 is calculated, and the composition assumed for the samples 3 and 13 is set so that the theoretical intensity matches the measured intensity stored for the samples 3 and 13 converted to the theoretical intensity scale. The composition of the samples 3 and 13 is calculated by successive approximation correction calculation, that is, by the FP method.

  Here, the samples 3 and 13 include the monitor sample 3 whose composition is calculated and stored in the calculation means 10A and the unknown sample 13 whose composition is unknown. The unknown sample 13 is an analysis target and is, for example, a liquid sample or a powder sample that scatters in a vacuum as it is, and the measurement surface 13a is covered with the film 12 when measured. The film 12 to be used is made of, for example, polyester, polypropylene, polyimide, etc., and has a thickness of about 2.5 to 12 μm. Although the composition is input from the input means 11, the thickness varies depending on the production lot, and the value indicated by the manufacturer is not sufficiently accurate, and the input from the input means 11 is arbitrary. The monitor sample 3 is a solid sample included in the X-ray fluorescence analyzer for calculating the thickness of the film 12.

  Samples 3 and 13 are accommodated in the container 14 and placed on the sample stage 8. In FIG. 1, a state in which the measurement surfaces 3 a and 13 a of the samples 3 and 13 accommodated in the container 14 are covered with the film 12 is shown in a vertical cross section, but for the monitor sample 3, the measurement surface 3 a is the film 12. Even if it is exposed without being covered with, it can be measured. The detection means 9 is composed of a spectroscopic element 5 that separates the fluorescent X-rays 4 generated from the samples 3 and 13 and a detector 7 that measures the intensity of each of the spectroscopic fluorescent X-rays 6. In addition, it is good also as a detection means not using the spectroscopic element 5, but a detector with high energy resolution.

  Specifically, the calculation means 10A included in the X-ray fluorescence analyzer of the first embodiment operates as shown in the flowchart of FIG. First, in step S1, the measurement intensity measured by the detection means 9 is stored for the monitor sample 3 whose measurement surface 3a is covered with the film 12 used for measurement of the unknown sample 13.

  Next, in step S2, the monitor sample 3 is excited by the primary X-ray 2 attenuated by the film 12 based on the composition stored for the monitor sample 3, the composition inputted for the film 12, and the assumed thickness for the film 12. Is calculated from the theoretical intensity of the fluorescent X-ray 4 that is attenuated by the film 12 and the measured intensity stored in step S1 for the monitor sample 3 whose measurement surface 3a is covered with the film 12 is calculated on the theoretical intensity scale. The assumed thickness of the film 12 is successively approximated and corrected so as to match the converted measured intensity, and the thickness of the film 12 is calculated and stored.

  Here, as the initial value of the thickness assumed for the film 12, when the thickness indicated by the manufacturer is input from the input means 11, it may be used, or when such input is not performed. The calculation unit 10A may select and use a plurality of candidate values that are input in advance, or may use one fixed value that is input in advance. Further, regarding the measurement line of which wavelength among the measurement lines that are the fluorescent X-rays 4 generated from each component in the monitor sample 3, the calculation of the apparatus according to the first embodiment is performed with respect to which measurement line the work of steps S1 and S2 is performed. It is assumed that the means 10A is predetermined.

  Next, in step S3, the measurement intensity measured by the detection means 9 is stored for the unknown sample 13 whose composition whose surface 13a is covered with the film 12 is unknown.

  Next, in step S4, excitation is performed by the primary X-ray 2 attenuated by the film 12, based on the assumed composition for the unknown sample 13, the composition input for the film 12, and the thickness stored in step S2 for the film 12. The theoretical intensity of the fluorescent X-ray 4 generated from the unknown sample 13 and attenuated by the film 12 is calculated, and the theoretical intensity and the measured intensity stored in step S3 for the unknown sample 13 whose measurement surface 13a is covered with the film 12 are theoretically calculated. The composition of the unknown sample 13 is calculated by successively correcting the assumed composition of the unknown sample 13 so that the converted measured intensity converted into the intensity scale matches.

  As described above, the X-ray fluorescence spectrometer of the first embodiment includes the calculation unit 10A that calculates the composition of the samples 3 and 13 by the FP method. With respect to the film 12 used for measurement, not only the attenuation of the fluorescent X-rays 4 by the film 12 but also the primary X-rays using the measurement intensity of the monitor sample 3 whose composition whose surface 12a is covered with the film 12 is known. The thickness of the film 12 is calculated and stored by the FP method in which the attenuation of the second film 12 is also incorporated in the theoretical strength calculation (steps S1 and S2). At this time, the work to be performed by the measurer is only the input of the composition of the film 12 and the measurement of the monitor sample 3 whose measurement surface 3 a is covered with the film 12.

  Then, the calculation means 10A uses the measured intensity of the unknown sample 13 whose measurement surface 13a is covered with the film 12, and based on the composition inputted for the film 12 and the stored thickness, the film 12 of the fluorescent X-ray 4 The composition of the unknown sample 13 is calculated by the FP method in which not only the attenuation due to but also the attenuation due to the film 12 of the primary X-ray 2 is incorporated in the theoretical intensity calculation (steps S3 and S4).

  That is, even if the composition of the film 12 used for the measurement of the unknown sample 13 is changed or the primary X-ray 2 used for the measurement of the unknown sample 13 is switched to change its wavelength distribution, the measurer performs in advance. The operations to be performed are only the input of the composition of the film 12 and the measurement of the monitor sample 3 whose measurement surface 3a is covered with the film 12, and the same composition and thickness as used for the measurement of the unknown sample as in the prior art. Using the X-ray film and primary X-rays with the same wavelength distribution, measure the standard sample both when the measurement surface is exposed and when covered with the film, and calculate the attenuation factor for each fluorescent X-ray. There is no need for memorizing it.

  Moreover, in the X-ray fluorescence analyzer of the first embodiment, when the thickness of the film 12 is calculated in advance and when the composition of the unknown sample 13 is calculated based on the thickness, the film 12 of the fluorescent X-ray 4 is used. Not only the attenuation but also the attenuation of the primary X-ray 2 by the film 12 is based on the FP method incorporated in the theoretical intensity calculation. Therefore, according to the X-ray fluorescence analyzer of the first embodiment, the composition of the unknown sample 13 whose measurement surface 13a is covered with the film 12 can be easily and accurately obtained.

  Next, a fluorescent X-ray analyzer according to the second embodiment of the present invention will be described. Since the operation of the calculation means 10B provided in the apparatus of the second embodiment is only partially different from the operation of the calculation means 10A provided in the apparatus of the first embodiment, the different parts will be described using the flowchart of FIG. To do. That is, when calculating the thickness of the film 12, the calculation means 10B provided in the apparatus of the second embodiment first uses the primary X-ray 2 based on the composition stored for the monitor sample 3 in step S0-1. The theoretical intensity of the measurement line 4 which is the fluorescent X-ray 4 generated from each component in the monitor sample 3 is calculated as the theoretical intensity without film of each measurement line 4.

  Next, in step S0-2, the monitor is excited by the primary X-ray 2 attenuated by the film 12 based on the composition stored for the monitor sample 3, the composition input for the film 12, and the assumed thickness for the film 12. The theoretical strength of each measurement line 4 generated from the sample 3 and attenuated by the film 12 is calculated as the theoretical strength of each measurement line 4 with film.

  Next, based on the theoretical strength without film calculated at step S0-1 and the theoretical strength with film calculated at step S0-2 for each measurement line 4 at step S0-3, attenuation by the film 12 at each measurement line 4 Calculate the rate. Here, “based on the theoretical strength without film and the theoretical strength with film” of each measurement line 4 means that each measurement line 4 uses the theoretical strength without film itself and the theoretical strength with film itself. For line 4, using the theoretical strength without film converted to the measured strength scale and the converted theoretical strength with film converted from the theoretical strength with film to the measured strength scale is also included.

  Next, in step S0-4, the standard deviation and variation coefficient in each measurement line 4 are calculated based on the theoretical strength with film calculated in step S0-2 for each measurement line 4. Here, “based on the theoretical strength with film of each measurement line 4” means using the converted theoretical strength with film obtained by converting the theoretical strength with film into a measurement strength scale for each measurement line 4.

  Next, in step S0-5, the measurement line 4 having the smallest product of the attenuation factor calculated in step S0-3 and the variation coefficient calculated in step S0-4 is selected as the optimum measurement line 4a.

  Next, in step S1A, the measurement intensity of the optimum measurement line 4a measured by the detection means 9 for the monitor sample 3 whose measurement surface 3a is covered with the film 12 is stored.

  Next, the film 12 having the initial value of the composition stored for the monitor sample 3 in step S2A, the composition input for the film 12, and the thickness assumed when the theoretical strength with film was calculated in step S0-2. The theoretical intensity of the optimum measurement line 4a generated from the monitor sample 3 and attenuated by the film 12 excited by the primary X-ray 2 attenuated by the film 12 is calculated based on the thickness assumed for The thickness assumed for the film 12 is set so that the measured intensity of the optimum measurement line 4a stored in step S1A for the monitor sample 3 whose measurement surface 3a is covered with 12 matches the converted measurement intensity converted to the theoretical intensity scale. The thickness of the film 12 is calculated and memorized by successively calculating the correction.

  In the fluorescent X-ray analyzer of the second embodiment, the calculation means 10B incorporates not only the attenuation of the fluorescent X-ray 4 by the film 12 but also the attenuation of the primary X-ray 2 by the film 12 in the theoretical intensity calculation for the monitor sample 3. Then, the theoretical strength without film and the theoretical strength with film of each measurement line 4 are calculated, and based on them, the optimum measurement line 4a for measuring the monitor sample 3 with the measurement surface 3a covered with the film 12 is selected. Therefore, the thickness of the film 12 can be calculated more accurately, the composition of the unknown sample 13 can be calculated more accurately based on it, and the labor of the measurer does not increase.

  Next, a fluorescent X-ray analyzer according to the third embodiment of the present invention will be described. Since the operation of the calculation means 10C provided in the apparatus of the third embodiment is only partially different from the operation of the calculation means 10B provided in the apparatus of the second embodiment, the different parts will be described using the flowchart of FIG. To do. That is, in the apparatus of the third embodiment, when the calculation unit 10C further calculates the thickness of the film 12, the thickness of the film 12 calculated in step S2B-1 as in step S2A and the step S0-2. In step S2B-3, the calculated thickness of the film 12 is set in step S0-2 until the difference from the thickness assumed when the theoretical strength with film is calculated falls within the predetermined range in the determination in step S2B-2. As the thickness assumed for the film 12 in step S0-2, the calculation from the theoretical strength with film to the calculation of the thickness of the film 12 in step S2B-1 is repeated.

  In step S2B-2, it is determined that the difference between the thickness of the film 12 calculated in step S2B-1 and the thickness assumed when the theoretical strength with film is calculated in step S0-2 is within a predetermined range. Then, in step S2B-4, the calculated thickness of the film 12 is stored.

  In the fluorescent X-ray analysis apparatus of the third embodiment, the difference between the thickness of the film 12 calculated by the calculation unit 10C calculated in step S2B-1 and the thickness assumed when the theoretical strength with film is calculated in step S0-2. Until the value falls within a predetermined range, the optimum measurement line 4a is selected again and the thickness of the film 12 is repeatedly calculated. Therefore, the thickness of the film 12 can be calculated more accurately, and based on this, the unknown can be determined more accurately. The composition of the sample 13 can be calculated, and the labor of the measurer does not increase.

DESCRIPTION OF SYMBOLS 1 X-ray source 2 Primary X-ray 3 Monitor sample 3a, 13a Measurement surface 4 Fluorescence X-ray (measurement line)
4a Optimal measurement line 9 Detection means 10A, 10B, 10C Calculation means 11 Input means 12 Film 13 Unknown sample

Claims (3)

An X-ray source for irradiating the sample with primary X-rays;
Detection means for measuring the intensity of fluorescent X-rays generated from the sample;
The measurement intensity measured by the detection means for the sample is stored, and the theoretical intensity of the fluorescent X-rays generated from the sample excited by the primary X-ray is calculated based on the assumed composition for the sample, Calculate the composition of the sample by successively correcting the assumed composition for the sample so that the theoretical intensity matches the measured measured intensity stored for the sample converted to the theoretical intensity scale. A calculation means;
A monitor sample whose composition is calculated and stored in the calculating means;
Input means for inputting the composition of the film when the measurement surface of the sample is covered with the film,
The calculating means is
Storing the measurement intensity measured by the detection means for the monitor sample whose measurement surface is covered with the film;
Based on the memorized composition for the monitor sample, the composition entered for the film and the assumed thickness for the film, it is excited by the primary X-rays attenuated by the film and generated from the monitor sample and attenuated by the film The theoretical intensity of the fluorescent X-ray is calculated, and the measured intensity stored for the monitor sample whose measurement surface is covered with the film is matched with the converted measured intensity converted to the theoretical intensity scale. Calculate and store the assumed thickness for the film in a sequential approximate correction to calculate the thickness of the film,
Stores the measured intensity measured by the detection means for an unknown sample whose composition is covered with the measurement surface,
Based on the assumed composition for the unknown sample, the composition entered for the film and the stored thickness for the film, it is excited by the primary X-rays attenuated by the film and generated from the unknown sample and attenuated by the film Calculating the theoretical intensity of the fluorescent X-ray, and so that the theoretical intensity and the measured intensity stored for the unknown sample whose measurement surface is covered with the film match the converted measurement intensity converted into a theoretical intensity scale, A fluorescent X-ray analyzer that calculates a composition of the unknown sample by sequentially correcting and calculating a hypothesized composition of the unknown sample. The X-ray fluorescence analyzer according to claim 1,
In calculating the thickness of the film by the calculating means,
Based on the composition stored for the monitor sample, the theoretical intensity of the measurement line, which is a fluorescent X-ray excited by the primary X-ray and generated from each component in the monitor sample, is calculated as the theoretical intensity without film of each measurement line. And
Based on the memorized composition for the monitor sample, the composition entered for the film and the assumed thickness for the film, it is excited by the primary X-rays attenuated by the film and generated from the monitor sample and attenuated by the film Calculate the theoretical strength of each measuring line as the theoretical strength with film of each measuring line,
Based on the theoretical strength without film and the theoretical strength with film of each measurement line, and calculating the attenuation rate by the film in each measurement line,
Based on the theoretical strength with film of each measurement line, calculate the standard deviation and coefficient of variation in each measurement line,
Select the measurement line with the smallest product of the attenuation factor and the coefficient of variation as the optimum measurement line,
Storing the measurement intensity of the optimum measurement line measured by the detection means for the monitor sample whose measurement surface is covered with the film;
The film based on the composition stored for the monitor sample, the composition input for the film, and the thickness assumed for the film with the initial thickness assumed when the theoretical strength with the film is calculated. Calculate the theoretical intensity of the optimum measurement line excited by the primary X-ray attenuated in the above and generated from the monitor sample and attenuated by the film, and the theoretical intensity and the monitor sample whose measurement surface is covered with the film Calculate the thickness of the film by successively correcting the assumed thickness of the film so that the stored measured intensity of the optimum measurement line matches the converted measured intensity converted to the theoretical intensity scale. X-ray fluorescence analyzer that stores and stores data. The fluorescent X-ray analyzer according to claim 2,
In calculating the thickness of the film by the calculating means,
The calculated thickness of the film is assumed as the thickness assumed for the film until the difference between the calculated thickness of the film and the thickness assumed when the theoretical strength with the film is calculated falls within a predetermined range. A fluorescent X-ray analyzer that repeatedly performs calculations from the theoretical intensity with film to the thickness of the film.

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