JPS62287136A - Qualitative analysis of element - Google Patents

Abstract

PURPOSE:To easily obtain an exact analysis value by scanning a prescribed wavelength range with the characteristic X-ray wavelength of an objective element as a center at a prescribed speed and determining the difference between the integrated value of the detection signal of the characteristic X-ray and the measured value of the background near the characteristic X-ray as the analysis value. CONSTITUTION:A sample S is excited by an excitation ray E to release the X-ray. A spectroscope driving device 3 is controlled by a CPU4 so that the range of the specified wavelength width with the wavelength of the characteristic X-ray of the objective element as a center is subjected to the wavelength scanning at the prescribed speed by an X-ray spectroscope 1. The detection signal of the characteristic X-ray is integrated by an X-ray signal counter 2 and the integrated value NP thereof is stored. The integrated value NB of the X-ray for the same time near the characteristic X-ray is measured and stored. NB is subtracted from NP and the difference therebetween is divided by the integration time. The quotient thereof is multiplied by a peak coefft. to calculate the analysis value which is then displayed on a display device 5.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention A. Industrial Application Field The present invention is directed to the analysis of elements using a wavelength scanning X-ray spectrometer such as an X-ray microanalyzer (EPMA) or a fluorescent X-ray device. Concerning how to perform automated qualitative analysis.

When performing automatic qualitative analysis of elements using a wavelength-scanning X-ray spectrometer such as an X-ray microanalyzer (EPMA) or a fluorescent X-ray device, the characteristic X-ray wavelength of each element and the background ( BG) l A constant wavelength is specified, these specified wavelength points are sequentially scanned with a scanning X-ray spectrometer, and the background (BG)
> The presence of each element can be determined by measuring the intensity and characteristic X-ray peak intensity, comparing the detected peak signal with the background signal, and determining whether there is a significant difference. It is based on the method of determining That is, according to this method, a peak measurement wavelength point and a BG measurement wavelength point are set for each element, the wavelength points are stored in the computer, and the spectrometer is sequentially driven to the wavelength points during measurement. are being measured. However, if the measurement wavelength point is set in this way and measurements are made, the error between the spectrometers will be +11
．． Wavelength reproducibility in one spectrometer (2) Shift in the generated spectrum caused by the combination of elements in the sample (3)
) etc., a deviation may occur between the set wavelength point and the wavelength point of the measured element, making it impossible to obtain correct qualitative analysis results. Conventionally, as a method to solve such problems, for (1), the measurement wavelength value of the target element is registered using a standard sample for each spectrometer, and for (21), a spectrometer with good reproducibility is used. For (3), it takes a lot of time to make adjustments before measurement, such as setting the wavelength point of the target element according to the specificity of the elemental combination state in the sample, and it is difficult to use automatic analysis. In other words, an X-ray spectrometer with good reproducibility has problems such as low analysis efficiency and accuracy, and high-precision X-ray spectrometers that are expensive.

C. Problems to be Solved by the Invention The present invention solves problems in setting the wavelength point in automatic qualitative analysis as described above, including the error between spectrometers, the reproducibility of one spectrometer, and the elemental composition of the sample. Even in situations where there is a discrepancy between the target element wavelength point and the set wavelength point due to wavelength shifts depending on the conditions, automatic qualitative analysis can be performed without the hassle of preparatory IY and without the need for particularly expensive spectroscopic equipment. The purpose is to enable accurate analysis results to be obtained through analysis.

29 Means for Solving Problems In the qualitative analysis method of elements performed using a wavelength scanning X-ray spectrometer, the element to be measured (target element) as shown in Figure 1.
The characteristic X-ray wavelength ^ generated from X-rays are measured at one wavelength point in the ground wavelength range, and the measured value is calculated as shown above. 2: Convert to a value equivalent to the integration time between ranges. The difference between the measured value and the calculated ffA value obtained in the above two measurements was corrected as necessary according to the shape of the peak waveform, and the corrected value was used as the analysis value.

(1) The wavelength position of the characteristic X-ray of the target element may deviate between the set value and the actual value due to the reasons mentioned above. For this reason, it is possible to obtain analysis values that do not actually exist for elements that actually exist.Wavelength scanning of a spectrometer 3 Characteristics of the target element 171 with a certain width centered on the wavelength point of the X-ray
A gap? Wavelength scanning is performed at a constant speed, and integral measurements are taken during the scanning.

As shown in Figure 1, even if the wavelength of the characteristic X-ray emitted from the target element in the sample deviates from the wavelength position λ on the spectrometer, the peak exists somewhere within the scanning width. Even if the position shifts, the integral of the X-ray intensity remains constant, and this integral value is the sum of the integral of the characteristic X-ray peak and the integral of the background in the scanning range. Therefore, a calibration measurement is performed to determine the background value at one wavelength point λ' in the background region, which is slightly away from the wavelength of the characteristic X-ray of the target element, and the background measurement value corresponding to the same time as the above integration time is measured or Obtain by calculation. Qualitative analysis of the target element can be performed by calculating the difference between the two measured values obtained in the above-mentioned main measurement and calibration measurement. According to this method, even if the spectral position of the X-ray is slightly shifted, elements will not be overlooked or underestimated, and the reliability of analysis will be improved.

Embodiment FIG. 2 shows an embodiment of the present invention. In Figure 2, S
is a sample, and E is an excitation ray that excites the sample S to emit X-rays. 1 performs wavelength scanning 3 using a scanning X-ray spectrometer. 2 is an X-ray signal counting device that detects spectroscopic X-rays and counts the detected signals to 31. 3 is an X-ray spectrometer driving device that controls wavelength scanning of the spectrometer 1; 4 is a CPU, and spectrometer drive device 3
control and control of the measurement data, scan a pre-specified wavelength range centered around the characteristic X-ray wavelength of the target element at a constant speed, and calculate the scanning time T time. During this period, the X41 detection signal is integrated by the X-ray signal counter 2 and stored as the integral value NP.Secondly, the X41 detection signal is integrated and stored as the integral value NP. Set Spectral 2S 1 to
The X-ray of that wavelength is detected and integrated, the integrated value is converted to a T time integrated value, and the converted value N8 is stored. Subtract the 11i calculation value N8 from the above integral value Np, and calculate the difference over the integration time T.
Calculate the analysis value by dividing by and multiplying the quotient by the peak coefficient. 5 is a display device that displays the analysis results.

In the above configuration, the schedule of X-ray spectrometry and the method of processing the detected measurement data stored in the CPU 4 are the main parts of the present invention, which will be explained using the flowchart of FIG.

Set the sample ms to the measurement point (a). The scanning X-ray spectrometer 1 is caused to scan at a constant speed a range of a constant wavelength width centered on the wavelength of the characteristic X-ray of the target element. The X-ray signal counting device 2 detects the X-rays separated by the spectrometer 1, counts (integrates) the amount of the scanning time T (c), and stores gL-divided data NP in the CPU 4. Set spectroscopy 3 to a wavelength point slightly distant from the wavelength of the characteristic X-ray of the target element (e).

The X-ray signal counting device 2 detects the X-rays separated by the spectroscope 1 and counts the amount (fa minutes) for a certain period of time t.

The counted value is multiplied by T7/c to convert it into a value corresponding to the integration time T (g). Store the converted value NB (H).

The analysis value I2 is calculated using the following arithmetic expression (1).

Analysis value Ip = aX (Np Na) /T-11
10, and a is 1 based on the peak half-width or peak waveform.
Constructed constant. For example, the reciprocal of the peak half-exploration expected for that element.

The analysis value Ip is compared with the background intensity to determine the presence or absence of the element, and the result is displayed on the display device 5 (N). Check whether detection of characteristic X-rays of all target elements has been completed (ru). If the detection of characteristic X-rays for all target elements has not been completed, the dynamic fj returns to (b) and repeats the above operation for the next element. The measurement ends when the detection of characteristic X-rays of all target elements is completed. The presence or absence of the element is identified based on the analytical value (2) obtained in this manner.

In this example, the wavelength of the characteristic X-ray of the target element is set,
The spectrometer 1 is designed to scan a range of a certain wavelength width centered on that wavelength;
The same effect can be obtained by scanning at a constant speed and integrating only over a prespecified range corresponding to the element to be measured.

Additionally, there are two ways to scan the scanning range at a constant speed: one is to drive the spectrometer continuously, and the other is to scan while skimming at regular time and wavelength intervals, but both methods have the same effect. i) et al.

Also, the value obtained by subtracting the ta calculation value Na from the integral value Np and dividing it by the integral time T is used as the peak count value, but if the integral time is kept constant, the same effect can be obtained by using the difference as is. .

G. Effects According to the present invention, qualitative analysis is possible even if the wavelength of the characteristic X-ray of the target element cannot be set accurately, which reduces costs, enables accurate analysis, and further improves analysis efficiency. Improved reliability

[Brief explanation of the drawing]

FIG. 1 is a peak signal diagram explaining the method of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a flowchart of the CPU. λ・ Wavelength position of characteristic X-ray 2 Δλ・ Difference between set wavelength position and actual wavelength position,
λ°...Background wavelength position 2a...Half width value of the scanning range. Ba background value, IP...peak value Fig. 1 Fig. 2

Claims (1)

[Claims] A wavelength scanning X-ray spectrometer scans at a constant speed a predetermined wavelength range centered on the characteristic X-ray wavelength of the element to be measured (target element), integrates the spectroscopic X-ray detection signal, and Measure X-rays at a wavelength position slightly distant from the characteristic X-ray wavelength of the element, convert the measured value to a value equivalent to the integration time between the above scanning ranges, and calculate the measured value obtained in the above two measurements. A qualitative analysis method for elements characterized by using the difference between the converted value and the converted value as the analytical value.