JPH06130004A - Fluorescent x-ray qualitative analysis method using spectrum processing - Google Patents

Abstract

PURPOSE:To provide a fluorescent X-ray qualitative analysis method using spectrum processing which can positively measure a plurality of elements from a measurement sample including the elements generating fluorescent X-rays with adjacent energy. CONSTITUTION:When X-rays 12 generated from an X-ray generation device 11 are applied to a measurement sample 13, fluorescent X-rays 14 generated from the measurement sample 13 are detected by a detector 15, and the signal is read as spectrum data through a signal processing means 17 for performing qualitative analysis of elements included in the measurement sample 13, spectrum data are obtained by the fluorescent X-rays 14 generated from the measurement sample 13. Then, the title method consists of a process for determining a plurality of peak generation positions 10 from the data, a process for previously selecting elements with each peak generation position 10 and at the same time for previously selecting elements with peak generation positions 8 and 9 which can exist near an area including the peak generation position for each peak generation position 10, and a process for performing spectrum processing of the selected elements.

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 qualitative analysis method using spectral processing.
TECHNICAL FIELD The present invention relates to a fluorescent X-ray qualitative analysis method capable of accurately performing qualitative analysis on a sample containing a plurality of elements such as (molybdenum) -Lα and S (sulfur) -Kα that generate fluorescent X-rays of close energies. It is a thing.

[0002]

2. Description of the Related Art Generally, in a fluorescent X-ray analyzer, as shown in FIG. 7, a measurement sample (hereinafter referred to as a sample) 2 to be measured by an X-ray generator 1 is irradiated with X-rays and emitted from the sample 2. The detected fluorescent X-rays 3 are detected by the detector 4, and the data collection device 41 obtains the spectrum data as shown in FIG.

At this time, since the energy value of the fluorescent X-rays 3 generated is determined for each element contained in the sample 2, this spectrum data has a peak at the energy position corresponding to the element contained in the sample 2. Have. The element contained in the sample 2 can be identified from the position of this peak.

In this conventional qualitative analysis method, if there is a peak in the energy position of the fluorescent X-ray obtained from a certain element in the spectral data obtained by the measurement, it is judged that the element is contained, and the peak is absent. I was trying to judge that the element was not contained.

[0005]

However, in the sample 2,
When a plurality of elements that generate fluorescent X-rays having energy close to each other are included, such as Mo-Lα and S-Kα,
For example, in FIG. 1, spectra 5 and 6 of the element showing the peak profile of fluorescent X-ray A and the peak profile of fluorescent X-ray B having the peaks 8 and 9 at the energy positions corresponding to these elements will be measured. However, in the conventional qualitative analysis method, in FIG. 1, the peak generation positions of the spectra 5 and 6 having the peaks 8 and 9 are not detected at the peak positions 8 and 9 due to the resolution of the detector 4, and the measured spectrum 7 is detected. Is detected as peak position 10. Therefore, even if the element showing the peak profile of the fluorescent X-ray A and the element showing the peak profile of the fluorescent X-ray B exist in the sample 2, the spectra 5 and 6 are not measured in the obtained spectrum data. However, since no peaks are measured at the peak positions 8 and 9, an erroneous qualitative analysis result that these elements are not contained may be obtained, and it is difficult to perform the qualitative analysis accurately. In order to avoid this, if the allowable range of the degree of coincidence of the peak positions is widened, at this time, even if only the spectrum 5 exists, the peak positions 8 and 9 are close to each other, so that it may be determined that the spectrum 6 also exists. is there.

The present invention has been made in view of the above problems, and an object of the invention is to perform a spectral treatment capable of reliably measuring these elements from a sample containing a plurality of elements which respectively generate fluorescent X-rays having energy close to each other. It is to provide a fluorescent X-ray qualitative analysis method used.

[0007]

In order to achieve the above-mentioned object, the present invention is directed to irradiating a measurement sample with X-rays emitted from an X-ray generator, and emitting fluorescent X-rays emitted from the measurement sample. When performing a qualitative analysis of the elements contained in the measurement sample by detecting with a detector and reading the signal as spectrum data through a signal processing means,
Each peak generation position is determined by a step of obtaining spectral data from fluorescent X-rays emitted from the measurement sample and determining a plurality of peak generation positions from the data, and the plurality of peak generation positions obtained from the data. From the step of pre-selecting the element to have, the step of pre-selecting an element having a peak occurrence position that can exist in the vicinity including this peak occurrence position for each peak occurrence position, and the step of performing spectrum processing of these selected elements X-ray qualitative analysis method using the following spectrum processing.

In the present invention, each step itself uses a known method, but by combining these steps, fluorescent X-rays having close energies are respectively generated as in spectra 5 and 6 in FIG. In the case of a measurement sample containing a plurality of elements, conventionally, in the spectral data obtained by the measurement, if there is a peak at the energy position of the fluorescent X-ray obtained from a certain element, it is determined that the element is included, and the peak is detected. If the peaks overlap, it is difficult to determine the element only by the peak position, and it is not the spectra 5 and 6 that can be obtained in the data but the resolution of the detector 4 if it is not. If it is spectrum 7, it is detected as one peak of spectrum 7, and the element is judged from the peak generation position 10. Elemental spectra 5,6 to data does not have a peak position 8, 9 can be reliably avoided so as to obtain a qualitative analysis erroneous results that are not included in the measurement sample. Even when the allowable range of the degree of coincidence of the peak positions is widened, if the measurement sample contains only the element of spectrum 5, an erroneous qualitative analysis result indicating that the element of spectrum 6 is included is obtained. It is possible to reliably avoid such a situation.

That is, according to the present invention, first, spectral data is obtained from fluorescent X-rays emitted from the measurement sample, and a plurality of peak generation positions are determined from the data.
For example, in FIG. 1, the peak generation position 10 is obtained.
Then, in the present invention, by the plurality of peak occurrence positions,
An element having each peak generation position is selected in advance, and an element having a peak generation position that can exist in the vicinity including this peak generation position is also selected in advance for each peak generation position. That is, assuming that the peak occurrence position included in the peak exists near the peak occurrence position 10 obtained in the above process, the elements 28 and 29 having the peak occurrence positions 8 and 9 are selected in advance (FIG. 3). reference).

Next, in the present invention, spectral processing of these selective elements is performed. This spectrum processing is for calculating the peak intensity of each selected element by separating the peaks of the selected elements. The spectral processing of this selective element
As an example, a case of using the least squares method using the following equation (1) will be described.

In FIG. 1, reference numeral 7 is a measurement spectrum,
Reference numerals 5 and 6 are the peak profile of the fluorescent X-ray A and the peak profile of the fluorescent X-ray B, respectively. Here, i ... spectral data number x _i ... X-ray energy y _i ... count rate (counts ^{_{/ sec) (S i) 2}} ... sample variance f _A (x _i) ... peak function f _B (x X-ray fluorescence A _i ) ... Peak function of fluorescent X-ray B a, b ... Coefficients to be obtained. In this embodiment, the coefficients a and b that minimize χ ² in the above equation (1) are obtained. The measurement intensity of the fluorescent X-ray A is And the measurement intensity of the fluorescent X-ray B is Is.

Further, as another example of the spectrum processing of the selective element, a case of using the overlap factor method will be described below. In FIG. 2, first, in step 101, the initial intensity N _A ⁰ of the peak profile of the fluorescent X-ray A is obtained. ROI strength of N _A ⁰ = E _{1 to} E ₂ Here, ROI is the Region of Inter.
It is an abbreviation of est and means a range for obtaining strength.
Then, similarly, the initial intensity N _B ⁰ of the peak profile of the fluorescent X-ray B is obtained. ROI intensity of N _B ⁰ = E _{3 to} E ₄

Next, at step 102, the peak function f _A (x _i ) of the fluorescent X-ray A and the peak function f _B (of the fluorescent X-ray B are shown.
x _i ), the overlap factor H _AB , defined below, in the overlap region of the peak profile of the fluorescent X-ray A and the peak profile of the fluorescent X-ray B,
_Ask for H _BA . H _AB = Σf _A (x) << where the total is x = E _{3 to} E ₄
》 ÷ Σf _A (x) << where the total is x = E ₁ ~
E ₂ >> H _BA = Σf _B (x) << where the total is x = E _{1 to} E ₂
÷ Σf _B (x) << where the total is x = E ₃ ~
E is _{4 "However, f A (x), f} B (x) is a function which is known in advance by the device.

Next, referring to FIG. 3, in step 103,
The measured intensity related to the ROI intensity of the fluorescent X-ray A is calculated by the following formula. N _A = N _A ⁰ −H _BA * N _B ⁰ Similarly, the measured intensity of the ROI intensity of the fluorescent X-ray B is calculated by the following formula. Then ^{_{N B = N B 0 -H AB}} * N A 0, in step 104, determine the measured intensity of the fluorescent X-ray A by the following equation. N _A = N _A ⁰ −H _BA * N _B Similarly, the measurement intensity of the fluorescent X-ray B is calculated by the following formula. ^{_{N B = N B 0 -H AB}} * N A

Then, in step 105, based on these data, the measured intensity N _A of fluorescent X-ray _A and fluorescent X-ray B
The respective convergence states of the measured intensities N _B are analyzed. When it is determined that the measured intensities N _A and N _B both converge, the peak separation in step 106 ends. In this way, the measurement intensity N _A of the fluorescent X-ray _A and the measurement intensity N _B of the fluorescent X-ray B can be obtained by the above steps. If the values of the measurement intensities N _A and N _B are above a certain value, it is judged that the element that emits the fluorescent X-rays is contained in the measurement sample.

As a result, for example, as shown by the dotted lines 21 and 22 in FIG. 5, the element showing the peak profile of the fluorescent X-ray A and the element showing the peak profile of the fluorescent X-ray B were measured. Since no peaks are measured at the peak positions 8 and 9, erroneous qualitative analysis results that these elements are not contained are not obtained, and the qualitative analysis can be performed accurately. Further, when only the peak profile of the fluorescent X-ray A is measured, it is not possible to obtain an erroneous qualitative analysis result that the element showing the peak profile of the fluorescent X-ray B is contained in the measurement sample.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fluorescent X-ray qualitative analysis method using spectral processing according to the present invention will be briefly described below with reference to the drawings. Note that the present invention is not limited thereby. In FIG. 6, 11 is an X-ray generator, 13 is a sample to be measured, 15 is a detector, and 16 is A /
D converter, 17 is a multi-channel analyzer, and 18 is a computer.

X-rays 12 emitted from the X-ray generator 11
Is emitted to the sample 13 and emitted from the sample 13
The line 14 is detected by the detector 15, and the signal is read as spectrum data by the computer 18 through the A / D converter 16 and the multi-channel analyzer 17. The position of the peak generated for each element is stored in the computer 18 in advance.

Spectral data is obtained from the fluorescent X-rays emitted from the measurement sample 13 and a plurality of peak generation positions are determined from the data. For example, in FIG. 1, the peak generation position 10 is obtained. Then, an element having each peak occurrence position is selected in advance by a plurality of peak occurrence positions, and an element having a peak occurrence position that can exist in the vicinity including this peak occurrence position is also selected in advance for each peak occurrence position. .

That is, assuming that the peak generation position included in the peak exists near the peak generation position 10 obtained in the above-mentioned process, the elements 28 and 29 having the peak generation positions 8 and 9 are selected in advance. (See Figure 4).

Next, spectral processing of these selective elements is performed. The spectral processing of the selected element is performed by using the least square method or the overlap factor method. The method of spectrum processing is not limited to these two generally used methods, and other preferable spectrum processing methods can be appropriately used.

As described above, when the peaks of the spectra are overlapped when the sample is measured, it was difficult to determine which element belongs to the peak generation position alone. List it as a candidate,
By performing spectrum processing (peak separation) using the least squares method or the overlap factor method, the peaks of the respective elements can be detected even in the case of spectra having overlapping peaks. As a result, qualitative accuracy can be improved.

[0023]

As described above, according to the fluorescent X-ray qualitative analysis method using the spectral processing of the present invention, when the peaks of the spectra are overlapped when the measurement sample is measured, only the peak generation position indicates which element It was difficult to judge whether or not this is because in the present invention, the elements contained in the peak are listed as candidates in advance, and spectral processing (peak separation) is performed using a known analysis means,
Even in the case of spectra with overlapping peaks, the peaks of the respective elements can be detected, and as a result, there is an effect that the accuracy of qualitative improvement can be improved. In addition, even if the allowable range of the degree of coincidence of the peak positions is widened, if the measurement sample contains only elements of a specific spectrum, an erroneous qualitative analysis that elements of other spectra are included There is an advantage that it is possible to surely avoid a situation in which a result is obtained.

[Brief description of drawings]

FIG. 1 Fluorescence X using spectral processing according to the present invention
It is a figure which shows the spectrum processing which could be detected by one Example of the line qualitative analysis method.

FIG. 2 is a flowchart showing the first half of the overlap factor method in the above embodiment.

FIG. 3 is a flowchart showing the latter half of the overlap factor method in the above embodiment.

FIG. 4 is a diagram showing selection of peak positions by rough qualification obtained in one step in the above-mentioned example.

FIG. 5 is a diagram showing peak separation by spectrum processing obtained in one step in the above-mentioned Example.

FIG. 6 is a structural explanatory view showing an analyzer used in a fluorescent X-ray qualitative analysis method.

FIG. 7 is a configuration explanatory view showing an analyzer similarly used in the fluorescent X-ray qualitative analysis method.

FIG. 8 is a diagram showing peak generation positions of a measurement sample.

[Explanation of symbols] 5 ... Spectrum of element showing peak profile of fluorescent X-ray A, 6 ... Spectrum of element showing peak profile of fluorescent X-ray B, 8 ... Peak of element showing peak profile of fluorescent X-ray A, 9 ... Peak of element showing peak profile of fluorescent X-ray B, 11 ... X-ray generator, 12 ...
X-ray, 13 ... Measurement sample, 14 ... Fluorescent X-ray, 15 detector,
16 ... A / D converter, 17 ... Multi-channel analyzer, 18 ... Computer.

Claims (4)

[Claims] 1. A measurement sample is irradiated with X-rays emitted from an X-ray generator, fluorescent X-rays emitted from the measurement sample are detected by a detector, and the signal is read as spectrum data through a signal processing means. Therefore, when performing a qualitative analysis of the elements contained in the measurement sample, the spectrum data is obtained from the fluorescent X-rays emitted from the measurement sample,
Based on the step of determining a plurality of peak generation positions from the data and the plurality of peak generation positions obtained from the data, an element having each peak generation position is selected in advance, and the peak generation position is determined for each peak generation position. A fluorescent X-ray qualitative analysis method using spectrum processing, which includes a step of previously selecting an element having a peak generation position that can exist in the vicinity including a position and a step of performing a spectrum processing of these selected elements. 2. The fluorescent X-ray qualitative analysis method using the spectral processing according to claim 1, wherein the measurement sample contains a plurality of elements that respectively generate fluorescent X-rays having energy close to each other. 3. The fluorescent X-ray qualitative analysis method using spectral processing according to claim 1, wherein the spectral processing of the selected element is performed by using a least square method or an overlap factor method. 4. The fluorescent X-ray qualitative analysis method using the spectral processing according to claim 1, wherein the spectral processing is performed for all the elements for which the qualitative analysis is performed.