JPH0752163B2 - Simplified quantitative analysis method using wavelength dispersive X-ray spectrometer - Google Patents

Description

The present invention relates to a simple quantitative analysis method using a wavelength dispersive X-ray spectrometer.

[Conventional technology]

Generally, when a sample is irradiated with an electron beam in a vacuum, X-rays are generated, and when the horizontal axis indicates the wavelength and the vertical axis indicates the X-ray intensity,
As shown in the figure, continuous X-rays and characteristic X-rays having a sharp peak at a specific wavelength are generated. This characteristic X-ray is peculiar to the elements that compose the sample, and the type of the element is known depending on the generation position. By comparing the peak intensity value with the peak intensity of the standard sample, the element content, that is, the concentration, can be determined. Required and quantitative analysis is performed. In this case, the standard sample and the unknown sample are different in the manner of generation of X-rays, the manner of absorption of the generated X-rays in the sample, and the like, which is corrected.

Explaining such a conventional quantitative analysis method, first, measurement conditions such as an accelerating voltage of an electron beam to be irradiated and an electron probe current are determined.

The intensity I _STD of the characteristic X-ray is obtained from a standard sample of known concentration.

The characteristic X-ray intensity I _UNK of the unknown sample is obtained under the same measurement conditions.

_{Calculate the} relative intensity K = I _UNK / I _STD .

Further, the following correction calculation is performed to obtain the concentration.

Concentration = relative intensity K × correction coefficient When performing ,, for the standard sample and the unknown sample for each element, as shown in FIG. 3, the peak value of the characteristic X-ray and the background intensity are usually obtained at two locations. ,
The intensity I, measured as _{I = P- (B 1 + B} 2) / 2.

[Problems to be solved by the invention]

However, in such a conventional quantitative analysis, a standard sample must always be measured at the same time as the measurement of an unknown sample, and therefore, an electronic probe microanalyzer (EP
MA) and X-ray fluorescence analyzers and other analyzers equipped with wavelength dispersive spectroscopes have a problem of requiring a great deal of analysis time.

The present invention is intended to solve the above problems, and provides a simple quantitative analysis method using a wavelength dispersive X-ray spectrometer capable of significantly shortening the quantification time without measuring a standard sample at the time of quantitative analysis. The purpose is to do.

[Means for solving problems]

Therefore, the simple quantitative analysis method by the wavelength dispersive X-ray spectroscope of the present invention uses the X-ray intensity I of the reference sample made of a stable substance.
Measuring _REF , measuring characteristic X-ray intensity I _STD of a standard sample containing the element to be measured at a known concentration,
Characteristic X-ray intensity I _{STD of} the standard sample measured at each stage
And calculating the ratio data of the X-ray intensity I _REF of the reference sample for each element, the step of measuring the X-ray intensity _I'REF of the reference sample during the quantitative analysis, the X-ray intensity of the measured reference sample I ′ _REF is multiplied by the ratio data of I _STD and I _REF to calculate the characteristic X-ray intensity of the standard sample, and the element is calculated from the calculated X-ray intensity of the standard sample and the measured X-ray intensity of the unknown sample. And a step of obtaining an X-ray relative intensity for each.

[Action]

The simple quantitative analysis method using the wavelength dispersive X-ray spectroscope of the present invention measures the ratio of the characteristic X-ray intensity of the standard sample to the X-ray intensity of the reference sample for each element in advance, and determines the ratio of the reference sample during quantitative analysis. By measuring the X-ray intensity to match the measurement conditions of the unknown sample and correcting the characteristic X-ray intensity of the standard sample that has been measured in advance, the measurement of the standard sample can be omitted, and the measurement time can be greatly shortened.

〔Example〕

 Embodiments will be described below with reference to the drawings.

FIG. 1 is a diagram showing a measurement process of a simple quantitative analysis method using a wavelength dispersive X-ray spectrometer according to the present invention.

First, as shown in FIG. 1A, the characteristic X-ray intensities of various standard samples are measured in advance. That is, first, measurement conditions such as accelerating voltage and probe current are determined (step), and then the intensity of the characteristic X-ray is measured with an X-ray intensity reference sample and set as I _REF (step).

The X-ray intensity reference sample is a sample made of a stable element that is not directly related to the elements of the standard sample or the unknown sample, such as iron (Fe) or cobalt (Co). Then, the characteristic X-ray intensity I _STD of the standard sample is measured for each element (step), and the ratio STD = I _STD / I _REF of this I _STD and I _REF is obtained for all the elements necessary for quantification, and obtained. Record the recorded data.

Then, the X-ray intensity of the unknown sample is measured and corrected by the process shown in FIG.

First, set the measurement conditions for an unknown sample (step), and X
The characteristic X-ray intensity _I'REF is measured with a line intensity reference sample (step). Next, the characteristic X-ray intensity I _UNK is measured for each element of the unknown sample (step). Next, the previously recorded STD is multiplied by the characteristic X-ray intensity I ′ _REF of the reference sample measured in steps, and the characteristic X-ray relative intensity of each element of the required standard sample is obtained by omitting the measurement of the standard sample, From this, the characteristic X-ray relative intensity K of each element is (Step). The concentration of each element is obtained by performing a correction calculation such as ZAF on the obtained relative intensity.

By using a reference sample with good reproducibility, changes in the entire measurement system such as changes in probe current and changes in detector sensitivity can be corrected by I _REF, and only probe current is measured. The analysis accuracy can be improved as compared with the case where the correction is performed.

Further, when using a plurality of spectroscopes, it is necessary to determine a reference for each spectroscope.

〔The invention's effect〕

As described above, according to the present invention, since it is not necessary to measure a standard sample during quantitative analysis, the quantitative analysis time in a wavelength dispersive spectrometer such as EPMA or a fluorescence analyzer can be significantly shortened,
The operation of moving the sample stage and the sample exchange can be significantly reduced. Moreover, since the change in the probe current is also corrected by measuring the reference sample, quantitative analysis can be performed without measuring the probe current.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a measurement process of a simple quantitative analysis method by a wavelength dispersive X-ray spectrometer according to the present invention, and FIG. 2 is a diagram showing X-ray intensity characteristics when a sample is irradiated with an electron beam, FIG. 3 is a diagram for explaining the method of calculating the peak value of the characteristic X-ray.

Claims (1)

[Claims] 1. An X-ray intensity I of a reference sample made of a stable substance.
Measuring the _REF, the step of measuring a characteristic X-ray intensity I _STD of the standard sample to be measured element is contained at a known concentration, the characteristic X-ray intensity I _STD of the standard sample measured in each stage
Of calculating the ratio data between the X-ray intensity I _REF of the reference sample and each element, recording, X-ray intensity I ′ _REF of the reference sample during quantitative analysis, X-ray intensity of the measured reference sample I ′ _REF is the _ISTD and I
Multiplying the ratio data with _REF to calculate the characteristic X-ray intensity of the standard sample, obtaining the relative X-ray intensity of each element from the calculated X-ray intensity of the standard sample and the measured X-ray intensity of the unknown sample A simple quantitative analysis method using a wavelength-dispersive X-ray spectrometer consisting of and.