JP2713120B2 - X-ray fluorescence analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluorescence spectrometer, and more particularly, to a technique for separating adjacent spectral lines.

[0002]

2. Description of the Related Art Generally, a fluorescent X-ray analyzer converts a fluorescent X-ray generated by irradiating a sample surface with primary X-rays into a spectrum having a wavelength component corresponding to each element by using a plurality of spectral crystals. Spectroscopically, the spectroscopic X-rays are detected by an X-ray detector, and the obtained spectral waveform is subjected to a smoothing process for removing a statistical error, a background removal for removing a background intensity included in measured data, A peak search process for detecting a peak in the measurement data and calculating a peak position, a peak intensity, and a background intensity is performed.

[0003] Further, for the detected peaks, the names of the elements and the names of the spectral lines are usually identified by using a wavelength table stored in advance in descending order of the peak intensities. Is also identified. At this time, the line intensity ratio table of each element stored in advance is used to estimate and subtract the intensity of the spectral line occupying the peak, and if there is a residue, it is assumed that the spectral lines of other elements overlap. Then, the identification process is again performed on the residual peaks, and the identification process is repeated for all the peaks, thereby obtaining the element name, the spectrum line name, and the intensity value for each peak. In addition, the quantitative calculation of each element can be executed using the detected element and the intensity value of the main spectral line of the element.

[0004]

However, in such a conventional example, in a process of identifying a spectral line, when a spectral line of two or more elements overlaps with a certain peak and is identified, that is, a different peak is detected. When the spectral lines of an element are in close proximity, the observed spectral lines affect each other's intensity and increase from the actual intensity, while the intensity of each element's spectral line is calculated. The line intensity ratio of the line intensity ratio table used when performing
The intensity value of the spectral line obtained as a result of the identification processing will include an error.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to make it possible to automatically separate adjacent spectral lines, to determine spectral line intensity more accurately, and to improve analysis accuracy. Aim.

[0006]

In order to achieve the above-mentioned object, the present invention is configured as follows.

That is, the present invention relates to an X-ray fluorescence spectrometer for detecting a peak from a measured spectrum waveform to identify a spectral line of an element, wherein a plurality of spectral lines of different elements overlap with the same peak. When identified, a separating means for separating the spectral lines by a function fitting calculation is provided, and the separating means has a wavelength interval calculated from the theoretical wavelength positions of the two spectral lines identified by overlapping, a predetermined value. When the value is larger than the value, the function fitting calculation is performed by fixing the wavelength interval without fixing the wavelength position of both spectral lines.

[0008]

According to the above arrangement, when a plurality of spectral lines of different elements are identified with respect to the same peak, the spectral lines are separated by function fitting calculation to obtain an intensity value of the spectral line closer to the true value. be able to.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an X-ray fluorescence analyzer according to one embodiment of the present invention. In FIG.
2 is a sample, 3 is a primary solar slit, 4 is a spectroscope, 5 is a secondary solar slit, 6 is an X-ray detector, 7 is a data analyzing and processing means, and a separating means for separating near spectral lines as described later. Computer having the function of
Reference numeral 8 denotes a display unit such as a CRT for displaying analysis results.

In such an X-ray fluorescence spectrometer, primary X-rays from the X-ray tube 1 are irradiated on the sample 2, and correspondingly, fluorescent X-rays generated from the sample 2 are transmitted through the primary solar slit 3 to the spectroscope 4. And split the X-rays into a secondary solar slit 5
Is detected by the X-ray detector 6 via the.

In the computer 7 to which the output of the X-ray detector 6 is given, the data is analyzed in accordance with the procedure shown in the flowchart of FIG.

That is, a smoothing process is performed on the measured spectrum waveform to remove a statistical error (step n1), a background intensity included in the measured data is removed (step n2), and the measured data is further processed. A peak search is performed to detect peaks in the data and calculate peak positions, peak intensities, and background intensities (step n3). For the detected peaks, a wavelength table and a line intensity ratio table stored in advance are used. To identify element names and spectral line names (step n
4) Output the result of the element identification processing to the display unit 8. The above processes are the same as in the conventional example. In this example,
The following processing is performed in order to separate adjacent spectral lines, determine their intensities more accurately, and improve analysis accuracy.

That is, first, N indicating the number of the peak is set to 1 (step n5). For the peak N, it is determined whether or not spectral lines of a plurality of elements have been identified (step n6). If the spectral lines of the elements are identified, for example, as shown in FIG. 3, if the spectral lines A and B of two elements are identified for one peak, the spectral lines A and The theoretical wavelength positions λ _A and λ _B of _B are read from the wavelength table (step n
7).

Next, the wavelength interval D = | λ _A −λ _B | between the spectral lines of the two elements is calculated (step n8), and it is determined whether or not this wavelength interval D is smaller than a predetermined value η. When it is determined (step n9) that it is not small,
Moving to step n10, the following function fitting calculation is performed. The determination in step n9 is because the separation calculation cannot be executed if the wavelength interval D between the spectral lines is too small. In this embodiment, the predetermined value η is dispersed in the target wavelength range. It is determined experimentally from the standard half width of the spectral line.

At step n10, a fitting range is determined, and the routine goes to step n11. In this embodiment, as shown in FIG. In addition, in FIG. 4, L is a background straight line.

Next, in step n11, a function fitting calculation is performed to obtain a function of the spectral lines A and B of each element. In this function fitting calculation, the wavelength interval (angular interval) D is fixed without fixing the wavelength position (angle) of the spectral line of each element.
Instead of fixing the wavelength position in this way, the wavelength interval D
Is fixed because the wavelength position of the measured spectrum waveform may not coincide with the theoretical wavelength position due to an error in the spectral system.

In the function fitting calculation of this embodiment, fitting is performed using a VOIGT function represented by the following equation, which is a composite function of a Gaussian function and a Lorentz function, as a theoretical function.

[0019]

(Equation 1)

The parameters of this fitting are as follows: c is the center of the peak, H is the height of the peak, and G is the Gaussian rate (0 <
G <1), W is the half-width, θ is the angle, and the half-width is fixed at the standard half-width in the target wavelength range used in step n9. At this time, fitting calculation is performed on the assumption that the left half widths and the right half widths of two overlapping spectral lines are equal.

By performing the above fitting calculations, the peak positions and peak intensities of the spectral lines A and B of each element are obtained from the obtained fitting function (step n12), and the results of the element identification processing obtained in step n4 are obtained. It is re-registered (step n13), and it is determined whether or not the processing has been completed for all peaks (step n1).
4) If not completed, 1 is added to N (step n15), and the process returns to step n6. If completed, the result is output to the display unit 8 as the final element identification processing result and the processing is terminated.

[0022]

As described above, according to the present invention, when spectral lines of a plurality of different elements are identified with respect to the same peak, the spectral lines are automatically separated by function fitting calculation to obtain a more true value. Can be obtained, and the analysis accuracy is improved. Moreover, in the function fitting calculation, instead of fixing the wavelength position of the spectral line, the function fitting calculation is performed with the wavelength interval of the overlapping spectral line fixed, so that the wavelength position of the measured spectral line may have an error. This makes it possible to easily separate the spectral lines even when they do not match the theoretical wavelength positions.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a fluorescent X-ray analyzer according to one embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is a spectral waveform diagram showing overlapping spectral lines.

FIG. 4 is a spectrum waveform diagram showing a fitting range.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray tube 2 Sample 4 Spectrometer 6 X-ray detector 7 Computer

Claims (1)

(57) [Claims] 1. An X-ray fluorescence spectrometer for detecting a peak from a measured spectrum waveform to identify a spectral line of an element when a plurality of spectral lines of a different element are identified and overlapped with the same peak. A separating means for separating the spectral lines by a function fitting calculation, wherein the separating means has a wavelength interval calculated from the theoretical wavelength positions of the two spectral lines identified by overlap, which is larger than a predetermined value. An X-ray fluorescence spectrometer, wherein a function fitting calculation is performed while fixing the wavelength interval without fixing the wavelength positions of the two spectral lines.