JPH08201319A - Fluorescent x-ray analyzing method - Google Patents

Abstract

PURPOSE: To provide a fluorescent X-ray analyzing method capable of calculating the accurate contents of contained elements in an analysis object sample even if the measured spectral lines differ for individual elements when the device sensitivity is obtained with a standard sample and when the intensity of the fluorescent X-rays generated from the analysis object sample is measured. CONSTITUTION: The device sensitivity is calculated and stored for individual spectral lines other than the reference spectral line for individual elements on the fluorescent X-rays 6 generated from main constituting elements of a standard sample 3. When the fluorescent X-rays 6 measured with the intensity on an analysis object sample 13 are other than the reference spectral line, each device sensitivity is used.

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 each element contained in a sample to be analyzed without using a calibration curve for a standard sample of known composition.

[0002]

2. Description of the Related Art Conventionally, as this kind of analysis method, the theoretical intensity of fluorescent X-ray of each contained element calculated assuming the composition of the sample and each content generated by irradiating the sample with primary X-rays Using the measured intensities of the fluorescent X-rays of the elements, the content ratios of the respective elements constituting the assumed composition are sequentially and approximately corrected and calculated so that the two intensities coincide, and the content ratios of the respective contained elements in the sample are calculated. There is a so-called fundamental parameter method, which is a fluorescent X-ray analysis method for obtaining the composition of a sample by calculating Here, the actually measured intensity of the fluorescent X-ray of each contained element generated from the sample is not the measured intensity itself but actually
For example, it is calculated as follows.

First, in a fluorescent X-ray analyzer to be used in advance, the intensity I _m of the fluorescent X-ray generated by irradiating the standard X-ray with a standard sample having a known composition is measured. On the other hand, to calculate the theoretical intensity I _t in content in the known composition. Then, for each element, a I _t / I _m that the theoretical intensity I _t was divided by the measured intensity I _m, is stored as an apparatus sensitivity I _t / I _m. Then, the fluorescence X generated by irradiating the sample to be analyzed whose composition is unknown with the primary X-ray
Measuring the intensity i _m lines, each element that caused the fluorescent X-ray, to calculate the product i _t of the system sensitivity as measured intensity i _m as the following equation. _{i t = i m × (I} t / I m) = i m × I t / I m The product i _t, the intensity i _t that speak terms of theoretical intensity scale intensity i _m of the fluorescent X-ray generated from the sample , and the other words are used as the measured intensity i _t.

[0004]

However, the fluorescent X-ray generated from one element is not one kind, that is, one wavelength,
From the relationship with the transition of electrons involved in the generation of fluorescent X-ray, Kα
₁ , Kα ₂ , Kβ ₁ , Kβ ₂ , Kβ ₃ , Lα ₁ , L
α ₂ , Lβ ₁ , Lβ ₂ , Lβ _3, ..., Lγ ₁ , Lγ ₂ , L
Fluorescence X of different wavelengths named γ ₃ … etc.
A line, or each spectral line, is generated. Where Kα
_{The 1-} line and the Kα ₂ line are double lines and are generally difficult to separate, so they are collectively referred to as the Kα line. Therefore, when the device sensitivity is obtained using a standard sample, the device sensitivity I _tA / I for the Kα line with reference to the Kα line for a certain element.
Although seeking _mA, the sample to be analyzed, because of overlap interference spectral lines Kα line, a situation such as that to measure the intensity i _mB for Kbeta ₁ line occurs instead.

[0005] The measured intensity i _tB in this case, as described above, i _tB = i _mB × but given by I _tB / I _mB, measured intensity I _mB is measured at Kbeta ₁ line Among the standard sample In the past, this was not
It was replaced with I _mA × (I _tB / I _tA ) using the measured intensity I _mA at the α ₁ ray and the theoretical intensity ratio I _tB / I _tA . As a result, the measured intensity i _tB is i _tB = i _mB × I _tA / I _mA = i _mB
× (I _tA / I _mA ), and the device sensitivity I _tA / I _mA at the reference Kα ₁ line is used as it is for the measured intensity i _mB at the Kβ ₁ line of the sample to be analyzed. Was there. The substitution is based on the assumption that the theoretical intensity ratio I _tB / I _tA and the measured intensity ratio I _mB / I _mA are equal, but the two do not actually match for the following reasons.

First, although the measured intensity differs depending on the wavelength characteristics of the spectroscopic system such as the dispersive crystal in the analyzer,
The theoretical intensity does not consider the wavelength characteristic of this spectroscopic system. Secondly, since it is difficult to completely separate and measure Kα ₁ and Kα ₂ rays, theoretical intensity treats them as Kα rays having a weighted average wavelength and total intensity, but in actual measurement, The degree of separation between the Kα ₁ ray and the Kα ₂ ray varies depending on the resolution of the apparatus. Thirdly, the physical constant of the generation efficiency of each fluorescent X-ray used for the theoretical intensity calculation contains an error.

For these reasons, the theoretical intensity ratio I _tB / I _tA
The measured intensity ratio I _mB / I _mA does not actually match. That is, in the conventional technique, when measuring the intensity of a reference spectral line generated from a standard sample to determine the apparatus sensitivity and when measuring the intensity of a spectral line generated from a sample to be analyzed, each element If the spectrum lines measured for the above are different, the actual measured intensity of the sample to be analyzed cannot be obtained, and therefore the accurate content rate of each contained element cannot be calculated.

The present invention has been made in view of the above-mentioned conventional problems. When the intensity of a reference spectral line generated from a standard sample is measured to determine the sensitivity of the apparatus, the spectral line generated from the sample to be analyzed is obtained. It is possible to provide a fluorescent X-ray analysis method capable of calculating an accurate content rate of each contained element in a sample to be analyzed even when the spectrum line measured for each element is different from that when the intensity of is measured. To aim.

[0009]

In order to achieve the above object, in the method of claim 1, the content ratio 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. In the fluorescent X-ray analysis method described above, first, a plurality of standard samples having different main constituent elements and having different contents are irradiated with primary X-rays, and the fluorescent X-rays generated from the main constituent elements are The intensity of each spectral line is measured, and the device sensitivity is calculated based on the measured intensity and the theoretical intensity. Then, for each element, among the calculated device sensitivities, the device sensitivities for the reference spectral lines are stored as reference device sensitivities, and the respective device sensitivities for the spectral lines other than the reference spectral lines are stored. Remember.

Next, the intensity of the fluorescent X-ray generated by irradiating the sample to be analyzed whose constituent element content is unknown with the primary X-ray is measured, and the intensity of the fluorescent X-ray is measured for each element. When the fluorescent X-ray whose intensity is measured is the reference spectral line, the reference device sensitivity is used, and when the fluorescent X-ray whose intensity is measured is a spectral line other than the reference spectral line, Using the sensitivity of each of the above,
The content rate of the element in the sample to be analyzed is calculated.

[0011]

According to the present invention, with respect to each spectrum line generated from the main constituent elements of the standard sample, the device sensitivity is calculated and stored for each spectrum line other than the reference spectrum line. Well,
When the fluorescent X-ray of which the intensity is measured in the sample to be analyzed is other than the standard spectral line, since the respective device sensitivities are used, the accurate content ratio of each contained element in the sample to be analyzed is always determined. It can be calculated.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, in the fluorescent X-ray analyzer to be used, a plurality of standard samples 3 having different main constituent elements and known contents are sequentially attached to the sample stage 8 in FIG.
The primary X-rays 2 generated from the radiation source 1 are irradiated, the generated secondary X-rays 4 are made incident on the spectroscope 5, and the spectral X-rays of the fluorescent X-rays 6 generated from the main constituent elements that are spectrally separated. Each time, the intensity I _mA , I _mB ... _Is measured by the detector 7. On the other hand, the theoretical strengths I _tA , I _tB ...
And the theoretical intensity I of each spectral line 6 is calculated.
By dividing _tA , I _tB ... By the respective measurement intensities I _mA , I _mB ..., The respective device sensitivities I _tA / I _mA , I _tB / I
Calculate _mB ... The standard sample 3 used here is often a pure substance.

This calculation is performed for each standard sample 3, that is, for each element, and for each element, the reference spectrum of the calculated device sensitivities I _tA / I _mA , I _tB / I _mB . Line, for example, the device sensitivity I _tA / I _mA at the Kα line is stored as the reference device sensitivity I _tA / I _mA , and the device sensitivity I _tB / I _mB for each spectral line other than the reference spectral line is also stored. Remember. here,
As the reference spectrum line, it is sufficient to adopt, for example, those measured with strong intensity for each element, for example, Kα ray for one element and Kβ ₁ ray for another element. May be different.

Next, similarly, the primary X is added to the sample 13 to be analyzed.
The line 2 is irradiated and the intensity of the generated fluorescent X-ray 6 is measured. Then, for each element, when the fluorescent X-ray 6 whose intensity is measured is a reference spectrum line, for example, Kα ray, the standard device sensitivity I _tA / I _mA is used, and the fluorescent X-ray 6 whose intensity is measured is used. Is a reference spectrum line, that is, a spectrum line other than the Kα line, the product sensitivity I _tB / I _mB is used to calculate the product of the measured intensity and the measured intensity. Then, the fluorescence X of each contained element calculated on the assumption of the measured intensity and the composition of the sample 13 to be analyzed.
Using the theoretical strength of the line, the content rates of the respective elements constituting the assumed composition are sequentially and approximately corrected and calculated so that the two strengths match, and the content rates of the respective contained elements of the analysis target sample 13 are calculated. By doing so, the composition of the sample is obtained.

As described above, according to the present embodiment, with respect to each spectrum line 6 generated from the main constituent elements of the standard sample 3, for each element, a spectrum line other than the reference spectrum line is also used. When the fluorescent X-ray 6 whose intensity is measured in the analysis target sample 13 is one other than the spectral line serving as the reference, the sensitivity of each device is used, and therefore the sensitivity is always analyzed. An accurate measured intensity of the target sample 13 is obtained, and therefore, an accurate content rate of each contained element in the analysis target sample 13 can be calculated.

In the present embodiment, for each element, the device sensitivity itself of each spectral line other than the reference spectral line is calculated and stored.
Calculate the ratio with the device sensitivity at the reference spectral line and store the device sensitivity ratio, and when calculating the measured intensity, recalculate each device sensitivity from the device sensitivity ratio and the reference device sensitivity. You may use. Also, these device sensitivities and device sensitivity ratios depend on the characteristics of the fluorescent X-ray analysis device used to obtain them, so if one device is used to obtain the other device of the same type. Can also be used. Further, even in the same apparatus, it can be used even if the analysis conditions such as the tube voltage of the X-ray tube change.

[Brief description of drawings]

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

[Explanation of symbols]

2 ... Primary X-ray, 3 ... Standard sample, 6 ... Fluorescent X-ray, 13 ... Analysis target sample.

Claims (1)

[Claims] 1. In a fluorescent X-ray analysis method for calculating the content of elements in a sample based on the intensity of fluorescent X-rays generated from the sample irradiated with X-rays, the main constituent elements are different and the content is known. Are irradiated with primary X-rays to measure the intensity of each fluorescent X-ray generated from the main constituent element for each spectral line, and based on the measured intensity and the theoretical intensity. The device sensitivity is calculated, and for each element, the device sensitivity for the reference spectral line of the calculated device sensitivity is stored as a reference device sensitivity, and each of the spectral lines other than the reference spectral line is stored. The sensitivity of the device is memorized, and the primary X is added to the sample to be analyzed whose constituent element content is unknown.
The intensity of the fluorescent X-ray generated by irradiating the X-ray is measured, and when the fluorescent X-ray whose intensity is measured is the reference spectral line for each element that generated the fluorescent X-ray, the reference device When the fluorescent X-ray whose intensity is measured using sensitivity is a spectrum line other than the above-mentioned reference spectrum line, the content rate of the element in the sample to be analyzed is calculated using the sensitivity of each of the above devices. X-ray fluorescence analysis method.