JP2002357571A - Wavelength dispersion type fluorescent x-ray analysis apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus that is capable of fully accurate analysis by effectively removing the influence of background such as high-order rays and electric noise in a wavelength dispersion type fluorescent X-ray analysis apparatus. SOLUTION: The distribution of intensity in secondary X rays 7 to the wave- height is outputted by a multiple wave-height analyzer 9, and background is removed by a waveform processing operation means 10 based on the distribution, thus calculating the intensity of fluorescent X rays to be analyzed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a so-called wavelength-dispersive X-ray fluorescence analyzer.

[0002]

2. Description of the Related Art Conventionally, in a wavelength-dispersive X-ray fluorescence spectrometer, a sample is irradiated with primary X-rays, X-rays generated from the sample are separated by a spectroscopic element, and the separated X-rays are separated. A pulse is generated by detecting with a detector. The voltage of this pulse, that is, the pulse height depends on the energy of the fluorescent X-rays, and the number of pulses per unit time depends on the intensity of the fluorescent X-rays. Therefore, as shown in FIG. 1, pulses having a predetermined pulse height range (called a window, here, 100 to 300) among the pulses are selected by a pulse height analyzer, and the counting rate (the number of pulses per unit time) is determined. It is determined by a counting means such as a scaler. That is, the shaded portion in FIG. 1 is the intensity of the fluorescent X-ray to be analyzed having a peak at a wave height of 200.

[0003]

However, the detector includes:
In addition to the fluorescent X-rays to be analyzed, a higher-order line, for example, a secondary line having a peak at a wave height of 400 can also be incident. Therefore, as described above, the wave height analyzer measures a wave height of 100 to 100 irrespective of the waveform in the window. When the sample of 300 is taken in, the intensity of the secondary X-ray near the wave height 300 is also included in the intensity of the fluorescent X-ray to be analyzed. Further, noise caused by the electric circuit is not removed. Therefore, analysis with sufficiently high precision cannot be performed.
This is a problem when the intensity of the fluorescent X-ray to be analyzed is weak.

On the other hand, as shown in FIG. 2, using a wave height analyzer having a window of two channels, a wave height of 300
By measuring the intensity of the secondary line at ~ 500 (including the electrical noise component in the portion with white spots), multiplying it by an appropriate coefficient, and subtracting from the intensity at 100-300 wave heights (shaded area) to correct Although there is an apparatus for measuring the intensity of the fluorescent X-rays to be analyzed, it cannot follow changes in the waveforms of the fluorescent X-rays and higher-order lines to be analyzed, and cannot remove electric noise. The accuracy cannot be analyzed,
In particular, this is a problem when the intensity of the fluorescent X-ray to be analyzed is weak.

The use of a multi-wave height analyzer (multi-channel analyzer) makes it easy to obtain the waveform of a fluorescent X-ray or a higher-order line to be analyzed, that is, a so-called wave height distribution curve. In the case of an X-ray analyzer equipped with a multi-height analyzer, only a rough waveform can be obtained to the extent that a peak can be read, so that it is easy to adjust the deviation of the waveform in the wave height direction due to the characteristic fluctuation of the detector. There are similar problems as described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In a wavelength-dispersive X-ray fluorescence spectrometer, the effects of background such as higher-order lines and electric noise are effectively removed, and a sufficient amount of light is obtained. It is an object of the present invention to provide an apparatus capable of performing highly accurate analysis.

[0007]

In order to achieve the above object, a wavelength-dispersive X-ray fluorescence spectrometer according to the present invention comprises: an X-ray source for irradiating a sample with primary X-rays; 2
A spectroscopic element that disperses secondary X-rays, and secondary X-rays disperse by the dispersive element are incident thereon, and pulses having a pulse height corresponding to the energy of the secondary X-rays are output in a number corresponding to the intensity of the secondary X-rays. And a detector for generating. A multi-peak analyzer that separates the pulses generated by the detector into a large number of peak ranges and outputs a distribution of the intensity of the secondary X-ray with respect to the peak, and a secondary X-ray output by the multi-peak analyzer The background is removed based on the intensity distribution of
Waveform processing calculating means for calculating the intensity of the line.

According to the apparatus of the present invention, the distribution of the intensity of the secondary X-ray with respect to the wave height is output by the multiplex wave height analyzer, and based on the distribution, the waveform processing / calculation means performs the processing of the higher-order line, electric noise, etc. Since the background is removed to calculate the intensity of the fluorescent X-rays to be analyzed, the effect of the background can be effectively removed and sufficiently high-precision analysis can be performed. In order to sufficiently exhibit such an effect, it is preferable that the number of wave height ranges for separation in the multiplex wave height analyzer is 512 or more.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus according to an embodiment of the present invention will be described below. As shown in FIG. 3, an X-ray source 4 such as an X-ray tube for irradiating a sample 1 placed on a sample table 2 with primary X-rays 3 and a fluorescent X-ray generated from the sample 1 are provided.
A spectroscopic element 6 that disperses the secondary X-ray 5 such as a ray, and a secondary X-ray 7 that is split by the spectroscopic element 6 are incident thereon, and a pulse having a wave height corresponding to the energy of the secondary X-ray 7 is generated. A detector 8 for generating a number corresponding to the intensity of the X-ray 7. Then, the pulse generated by the detector 8 is classified into a large number of consecutive equally-spaced wave height ranges, and a multiplex height analyzer 9 for outputting a distribution of the intensity of the secondary X-rays 7 with respect to the wave height; The background is removed based on the distribution of the intensity of the secondary X-rays 7 output from the detector 9, and the fluorescent X-rays to be analyzed are removed.
A waveform processing / calculating means for calculating the intensity of the line.
The number of wave height ranges for separation in the multiplex wave height analyzer 9 is preferably 512 or more, and is actually 4096 or less. Here, a 512-channel multiplex height analyzer 9 is used.

In this apparatus, the multiple wave height analyzer 9 calculates the distribution of the intensity of the secondary X-ray with respect to the wave height as shown in FIG. 1 or FIG. Output. Then, based on the distribution, the waveform processing / calculating means 10 calculates the intensity of the fluorescent X-ray to be analyzed by removing backgrounds such as higher-order lines and electric noise. For example, as shown in FIG. 4, by performing a function separation operation by the waveform processing operation unit 10, the influence of the secondary line and the electric noise is removed, and the integrated intensity (the area of the hatched portion) is obtained for the fluorescent X-ray to be analyzed. Is calculated. At this time, fitting is performed using a Gaussian function, a pseudovoid function, or the like as a peak function (waveform of a fluorescent X-ray or a higher-order line of an analysis target) and an exponential function as an electrical noise component. Instead of these functions, other more appropriate functions or waveforms previously obtained experimentally and stored may be used.

More simply, as shown in FIG. 5, a background including a higher-order line, electric noise, and the like is approximated by a straight line. You may. That is, the integrated intensity (the area of the hatched portion) surrounded by the waveform having the peak at the wave height 200 and the straight line connecting the left and right lower ends in the mountain-shaped waveform is
It may be calculated as the intensity of the fluorescent X-ray to be analyzed. At this time, instead of the straight line, a quadratic curve, an exponential function, a logarithmic function, or a waveform previously obtained experimentally and stored may be used. Note that as a pre-process of the above-described waveform processing, a smoothing process such as the Savitzky-Golay method may be performed. As described above, according to the apparatus of the present embodiment, sufficiently high-accuracy analysis can be performed by effectively removing the influence of the background.

[0012]

As described above in detail, according to the present invention, in a wavelength-dispersive X-ray fluorescence spectrometer, the distribution of the intensity of secondary X-rays with respect to the wave height is output by a multi-wave height analyzer. Based on the distribution, the waveform processing calculation means removes background such as high-order lines and electric noise to calculate the intensity of the fluorescent X-ray to be analyzed, so that the influence of the background is effectively removed, The analysis can be performed with sufficiently high accuracy, and the effect is particularly remarkable when the intensity of the fluorescent X-ray to be analyzed is weak.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of operation contents of a wave height analyzer and the like included in a conventional wavelength dispersive X-ray fluorescence analyzer.

FIG. 2 is a diagram showing another example of the operation content.

FIG. 3 is a schematic diagram showing a wavelength-dispersive X-ray fluorescence spectrometer according to one embodiment of the present invention.

FIG. 4 is a diagram showing an example of operation contents of a multiplex height analyzer and the like provided in the apparatus.

FIG. 5 is a diagram showing another example of the operation content.

[Explanation of symbols]

Reference Signs List 1 ... sample, 3 ... primary X-ray, 4 ... X-ray source, 5 ... secondary X-ray generated from sample, 6 ... spectroscopic element, 7 ... secondary X-ray separated by spectroscopic element, 8 ... detector , 9 ... Multiple height analyzer, 10
... waveform processing calculation means.

Claims (2)

[Claims] An X-ray source for irradiating a sample with primary X-rays, a spectroscopic element for separating secondary X-rays generated from the sample, and a secondary X-ray split by the spectroscopic element are incident on the sample. A detector that generates pulses having a wave height corresponding to the energy of the secondary X-rays in a number corresponding to the intensity of the secondary X-rays; A multi-height analyzer that outputs the distribution of the intensity of the secondary X-ray, and based on the distribution of the intensity of the secondary X-ray output by the multi-height analyzer, the background is removed, and the intensity of the fluorescent X-ray to be analyzed is obtained. Wavelength-dispersive X-ray fluorescence analyzer comprising: 2. The wavelength-dispersive X-ray fluorescence analyzer according to claim 1, wherein the number of wave height ranges for separation in the multiplex wave height analyzer is 512 or more.