JP2645226B2 - X-ray fluorescence analysis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent X-ray analysis method for calculating the content of elements in a sample to be analyzed without using a calibration curve for a standard sample having a known composition.

[0002]

2. Description of the Related Art Conventionally, as an analysis method of this kind, the theoretical intensity of fluorescent X-rays of each element of a sample calculated based on the assumption of the content of the element in the sample and the generation of the X-ray from the sample have been described. Using the measured X-ray fluorescence intensity of each element to be used, the assumed content of the element is corrected by successive approximation so that the two intensities match each other, and the fluorescence X for calculating the content of the element in the sample is calculated. There is a line analysis method, a so-called fundamental parameter method. Here, the measured intensity of the fluorescent X-ray of each element generated from the sample by irradiating the X-ray is actually obtained, for example, as follows.

[0003] In the first method, first, in a fluorescent X-ray analyzer to be used in advance, a plurality of standard samples (generally a pure substance or an oxide) whose main constituent elements are different from each other and whose contents are known are determined. a primary X-ray to measure the intensity I _m of the fluorescent X-ray generated by irradiating. On the other hand, it calculates the theoretical intensity I _tp in theoretical strength I _t and containing 100% of the known content and calculate the ratio I _tp / I _t. Then, by multiplying the ratio I _tp / I _t in the measured intensity I _m, wherein each main constituent elements, a fluorescent X-ray content of the element in the standard sample is a standard in the case of a 100% intensity _{I m × I tp / I t} ( hereinafter,
This intensity is referred to as a standard intensity). Then, the intensity I of fluorescent X-rays generated by irradiating primary X-rays to a sample to be analyzed whose content of constituent elements is unknown is
Is measured, and an intensity ratio i ₁ between the measured intensity I and the standard intensity is calculated for each spectrum of the generated fluorescent X-rays according to the following equation. i ₁ = I / (I _m × I _tp / I _t ) = I × I _t / I _m × I _tp This intensity ratio i ₁ is the so-called relative intensity i ₁ of the fluorescent X-rays generated from the sample. used as the measured intensity i _1.

In the second method, first, in a fluorescent X-ray analyzer to be used in advance, a plurality of standard samples (generally a pure substance or an oxide) whose main constituent elements are different from each other and whose contents are known are determined. a primary X-ray to measure the intensity I _m of the fluorescent X-ray generated by irradiating. On the other hand, to calculate the theoretical intensity I _t of the known content. And
By dividing the measured intensity I _m at its theoretical strength I _t, the per main constituent elements, keep calculating the sensitivity I _m / I _t of the measured intensity to the theoretical strength. Then, the intensity I of fluorescent X-rays generated by irradiating primary X-rays to a sample to be analyzed whose content of constituent elements is unknown is measured, and the measured intensity is measured for each spectrum of the generated fluorescent X-rays. the ratio i ₂ of the sensitivity and I is calculated by the following equation. i ₂ = I / (I _m / I _t ) = I × I _t / I _m This ratio i ₂ is the intensity i _{2 obtained} by converting the intensity I of the fluorescent X-rays generated from the sample into a theoretical intensity scale. That it is used as the actual measured intensity i _2.

Here, for the measurement for calculating the standard intensity or sensitivity, the standard intensity or sensitivity obtained by performing the measurement once once for about 30 elements in the fluorescent X-ray analyzer to be used is stored. Often, it is not necessary to carry out each measurement of the sample to be analyzed. If the sample to be analyzed contains an element for which standard intensity or sensitivity has not been determined, linear interpolation or the like is performed on the element from the standard intensity or sensitivity of the element before and after in the atomic number to determine the standard for that element. It is a substitute for intensity or sensitivity. This method is generally called semi-quantitative analysis.

[0006]

However, the sample to be analyzed may contain an element which is not close in atomic number to the element for which the standard intensity or the sensitivity has been determined. According to the method, an accurate measured intensity is not always obtained, and thus an accurate analysis cannot be performed. In order to obtain an accurate measured intensity, individual fluorescent X
In a line analyzer, measurement for calculating standard intensity or sensitivity has to be performed for many elements that may be included in a sample to be analyzed, which requires a great deal of time and effort.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is an X-ray fluorescence analyzer used in an X-ray fluorescence analysis method for calculating the content of elements based on the intensity of X-ray fluorescence from a sample. It is an object of the present invention to provide an analysis method that can easily and accurately calculate the content of an element even for an analysis target sample containing an element for which standard intensity or sensitivity is not determined.

[0008]

According to a first aspect of the present invention, there is provided a method for calculating the content of an element in a sample based on the intensity of fluorescent X-rays generated from the sample irradiated with the X-rays. In the fluorescent X-ray analysis method described above, first, in a standard fluorescent X-ray analyzer, the fluorescence generated by irradiating primary X-rays on a plurality of standard samples whose main constituent elements are different and whose contents are known is The intensity of X-rays is measured, and based on the measured intensity, the intensity of the fluorescent X-ray as a standard when the content of the element in the standard sample is 100% is calculated for each of the main constituent elements. ,
The standard intensity measured by these reference devices is stored.

In another X-ray fluorescence spectrometer of the same type as the above-mentioned X-ray fluorescence spectrometer serving as a reference, a plurality of standard samples whose main constituent elements are different and whose contents are known are referred to as a reference X-ray fluorescence. Using a smaller number of standard samples than the standard samples used in the X-ray analyzer, measure the intensity of fluorescent X-rays generated by irradiating primary X-rays, and based on the measured intensity, for each of the main constituent elements, When the content of the element in the standard sample is assumed to be 100%, the intensity of the fluorescent X-ray as a standard is calculated, and the standard intensity measured by the other device is stored. Then, in the other X-ray fluorescence spectrometer, the X-ray fluorescence generated by irradiating the sample to be analyzed whose content ratio of the constituent elements is unknown with primary X-rays is obtained.
Measure the intensity of the line, when the fluorescent X-rays are generated from the element whose standard intensity is not measured by the other device, using the standard intensity measured by the reference device and interpolated by the stored standard intensity, Calculate the element content in the sample to be analyzed.

[0010] In order to achieve the above object, the method according to claim 2, wherein the content of the element in the sample is calculated based on the intensity of the fluorescent X-ray generated from the sample irradiated with the X-ray. First, in a standard fluorescent X-ray analyzer, the intensity of fluorescent X-rays generated by irradiating primary X-rays on a plurality of standard samples whose main constituent elements are different and whose contents are known is measured. Then, the sensitivity of the measured intensity to the theoretical intensity is calculated for each of the main constituent elements based on the measured intensity, and the sensitivities measured by the reference devices are stored.

In another X-ray fluorescence spectrometer of the same type as the above-mentioned X-ray fluorescence spectrometer serving as the reference, a plurality of standard X-ray spectroscopy having different main constituent elements and a known content of the same is used. Using a smaller number of standard samples than the standard samples used in the X-ray analyzer, measure the intensity of fluorescent X-rays generated by irradiating primary X-rays, and based on the measured intensity, for each of the main constituent elements, The sensitivity of the measured intensity to the theoretical intensity is calculated, and the sensitivities measured by the other devices are stored. Then, in the other X-ray fluorescence analyzer, the intensity of the X-ray fluorescence generated by irradiating primary X-rays to a sample to be analyzed whose content of constituent elements is unknown is measured. When fluorescent X-rays are generated from an element whose sensitivity has not been measured, the content of the element in the sample to be analyzed is calculated using the sensitivity measured by the reference device and interpolated by the stored sensitivity.

[0012]

According to the present invention, the standard fluorescent X
In a X-ray analyzer, standard intensities or sensitivities are determined for a number of elements that may be contained in a sample to be analyzed. When fluorescent X-rays of an element whose sensitivity is not measured are generated, the content of the element in the sample to be analyzed is determined using the standard intensity or sensitivity interpolated by the standard intensity or sensitivity measured and stored by the reference device. Since the calculation is performed, the content of the element can be easily and accurately calculated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, first, in a fluorescent X-ray analyzer serving as a first reference, a plurality of standard samples 3 whose main constituent elements are known and different from each other are attached to a sample table 8, and the X-ray source 1 shown in FIG. Is irradiated with the primary X-rays 2 generated from the above, the generated secondary X-rays 4 are made incident on the spectroscope 5, and the intensity of the fluorescent X-rays 6 generated from the main constituent elements which have been split is detected by the detector 7. Measure with On the other hand, the theoretical strength at the known content and the theoretical strength at a content of 100% are calculated,
Find the ratio. Then, by multiplying the measured intensity by the ratio, for each of the main constituent elements, a standard fluorescent X-ray intensity is calculated when the content of the element in the standard sample is 100%. These are stored as standard intensities measured by the reference device. In the reference device, standard strengths are obtained for about 70 elements from boron having an atomic number of 5, which is likely to be contained in the sample 13 to be analyzed.

For example, _assuming that fluorescent X-rays 6 having an intensity S _0M are generated from a standard sample 3 having a known content in a reference device with respect to manganese, the standard intensity S _1M for manganese is the known intensity in manganese. Theoretical strength I _tM at content rate and theoretical strength I at 100% content rate
_By calculating _tpM, it is calculated by the following equation. Standard strength _{S 1M = S 0M × I tpM} / I tM each of these elements, as shown in FIG. 2, there is the relationship that forms a gentle curve to atomic number, the relative magnitude relation, the same The relationship is the same for the same type of X-ray fluorescence analyzer using the X-ray source 1, the spectroscope 5, and the detector 7 in FIG.

Next, in the second X-ray fluorescence analyzer of the same type as the reference device, the standard intensity is obtained and stored in the same manner as in the reference device. However, in the second apparatus, the standard intensity may be obtained for about 20 main elements among many elements that may be included in the sample 13 to be analyzed. Then, in the second device, the intensity of the fluorescent X-ray 6 generated by irradiating the primary X-ray 2 to the sample 13 whose content of the constituent elements is unknown is measured, and the standard value is set in the second device. When the fluorescent X-ray 6 is generated from an element whose intensity is not measured, the standard intensity measured by the reference device and interpolated by the stored standard intensity is used.

For example, standard strengths S _1T , S _1M , and S _1C of titanium, manganese, and copper are determined in the reference device, and standard strengths S _2T , S 1 of titanium and copper are determined in the second device. It is assumed that _2C is required, but the standard strength S _{2M of} manganese is not required. And the second
When the primary X-ray 2 is irradiated to the sample 13 to be analyzed whose content of constituent elements is unknown in the apparatus of the above, and the fluorescent X-ray 6 is generated from the manganese, the standard intensity S of the manganese in the second apparatus is _2M is required. Here, as described above, the relative magnitude relationship between the standard intensities is the same relationship in the case of the same type of fluorescent X-ray analyzer, and if the relationship is determined in detail by the reference device, the second device can be used. Is also applicable. Therefore, the atomic numbers of titanium, manganese, and copper are each 2
Since it is 2, 25, 29, the standard intensity S _2M of manganese in the second device is the standard intensity S _1T , S _1M , measured and stored in the reference device as shown in the following equation (1). It is obtained by linearly interpolating the atomic number using _S1C .

[0017]

(Equation 1)

Here, instead of the linear interpolation, another function such as a quadratic equation may be used. In addition, interpolation can be performed using the energy or wavelength of fluorescent X-rays instead of the atomic number as a numerical value representing the element. As described above, according to the first embodiment, in the reference device, the standard intensities of many elements that may be included in the sample 13 to be analyzed are determined in advance, and the standard X-ray fluorescence analyzer is used for analysis. When a fluorescent X-ray 6 of an element whose standard intensity is not measured by the target sample 13 is generated from the target sample 13, the standard intensity measured by the reference device and interpolated by the stored standard intensity is used. The content of elements in 13 can be easily and accurately calculated.

Next, a second embodiment will be described. Second
In the embodiment, the sensitivity is interpolated in the same manner as the standard intensity is interpolated in the first embodiment. For example, _assuming that fluorescent X-rays 6 of intensity S _0M are generated from a standard sample 3 of a known content in a reference device with respect to manganese, the sensitivity Q _1M for manganese is the theoretical value at the known content of manganese. By calculating the intensity _{ItM, it} is calculated by the following equation. Q _1M = S _0M / I _tM The sensitivity of each of these elements has a gentle curve with respect to the atomic number as shown in FIG. 3, and the relative magnitude relationship is the same as that of X in FIG. The same relationship exists between X-ray fluorescence analyzers of the same model using the radiation source 1, the spectroscope 5, and the detector 7.

For example, in the reference device, the sensitivities Q _1T , Q _1M , and Q _{1C of} titanium, manganese, and copper are determined, and in the second device, the sensitivities Q _2T of titanium and copper are obtained. , Q _2C are required, but sensitivity Q _2M of manganese is not required. And the second
When the primary X-ray 2 is irradiated to the sample 13 to be analyzed whose content of constituent elements is unknown in the apparatus of the above, and the fluorescent X-ray 6 is generated from the manganese, the sensitivity Q _2M of the manganese in the second apparatus is Is required. Here, similarly to the first embodiment, the atomic numbers of titanium, manganese, and copper are 22, 22, respectively.
Since they are 25 and 29, the sensitivity Q _2M of manganese in the second device is determined by the sensitivities Q _1T , Q _1M and Q _1C measured and stored in the reference device as shown in the following equation (2). It is obtained by linearly interpolating the numbers.

[0021]

(Equation 2)

As described above, according to the second embodiment, the second
When the fluorescent X-ray 6 of an element whose sensitivity is not measured by the device 13 is generated from the sample 13 to be analyzed, the sensitivity interpolated by the sensitivity measured and stored by the reference device is used. The content of the element in the target sample 13 can be easily and accurately calculated.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between standard intensity and atomic number of each element in the present invention.

FIG. 3 is a diagram showing the relationship between sensitivity and atomic number of each element in the present invention.

[Explanation of symbols]

2 ... primary X-ray, 3 ... standard sample, 6 ... fluorescent X-ray, 13 ... sample to be analyzed.

Claims (2)

(57) [Claims] An X-ray fluorescence analysis method for calculating the content of an element in a sample based on the intensity of X-ray fluorescence generated from the sample irradiated with X-rays. For a plurality of standard samples whose constituent elements are different and whose content is known, the intensity of fluorescent X-rays generated by irradiating primary X-rays is measured, and based on the measured intensity, for each of the main constituent elements, By calculating the intensity of the fluorescent X-ray which is a standard when the content of the element in the standard sample is 100%,
The standard intensities measured by the reference devices are stored, and in another X-ray fluorescence analyzer of the same type as the reference X-ray fluorescence analyzer, a plurality of components whose main constituent elements are different and whose content is known are different. Regarding the standard sample, the fluorescent X-rays generated by irradiating the primary X-ray by using a smaller number of standard samples than the standard sample used in the standard fluorescent X-ray analyzer.
The intensity of the X-ray is measured, and based on the measured intensity, the intensity of the fluorescent X-ray as a standard when the content of the element in the standard sample is 100% is calculated for each of the main constituent elements, The standard intensities measured by these other devices are stored, and in the other X-ray fluorescence analyzer, primary X-rays are generated by irradiating a sample to be analyzed whose content of constituent elements is unknown. When the intensity of the fluorescent X-ray is measured and the fluorescent X-ray is generated from the element whose standard intensity is not measured by the other device,
A method of X-ray fluorescence analysis, wherein the content of an element in a sample to be analyzed is calculated using a standard intensity interpolated by a standard intensity measured and stored by the reference device. 2. An X-ray fluorescence analysis method for calculating the content of an element in a sample based on the intensity of X-ray fluorescence generated from the sample irradiated with X-rays. For a plurality of standard samples whose constituent elements are different and whose content is known, the intensity of fluorescent X-rays generated by irradiating primary X-rays is measured, and based on the measured intensity, for each of the main constituent elements, The sensitivity of the measured intensity with respect to the theoretical intensity is calculated, and the sensitivities measured by the reference devices are stored, and in another X-ray fluorescence analyzer of the same type as the reference X-ray fluorescence analyzer, the main constituent elements are For a plurality of standard samples whose contents are known differently, the number of standard samples used in a standard fluorescent X-ray analyzer is smaller than the number of standard samples, and the fluorescent light generated by primary X-ray irradiation is used. X
Measure the intensity of the line, based on the measured intensity, for each of the main constituent elements, calculate the sensitivity of the measured intensity to the theoretical intensity, and store the sensitivities measured by the other devices, In an X-ray fluorescence analyzer, the intensity of X-ray fluorescence generated by irradiating primary X-rays to a sample to be analyzed whose content of constituent elements is unknown is measured, and the sensitivity is measured by the other apparatus. X-ray fluorescence analysis characterized by calculating the content of an element in a sample to be analyzed using the sensitivity measured by the reference device and interpolated by the stored sensitivity, when X-rays are generated from a non-existing element. Method.