JP2001133419A - X-ray elemental analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray elemental analyzer by which even a nonspecialist can get a knowledge about the reliability of a measured value and by which an analytical measurement of required accuracy can be performed automatically. SOLUTION: A prescribed region of concern is set on a measuring spectrum obtained by a preliminary measurement before the start of a formal measurement. A statistical error about the measuring spectrum of the set region of concern is calculated. An estimated accuracy with reference to the measuring time which is set in advance on the basis of the calculated statistical error is calculated and displayed. When the accuracy is different from an expected accuracy by an operator, the operator corrects the estimated accuracy to an expected accuracy value, and the measuring time which is calculated on the basis of the statistial error is set. Thereby, a measurement of required accuracy can be performed automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to an X-ray elemental analyzer in which an analytical measurement of an expected accuracy set and inputted is automatically performed.

TECHNICAL FIELD OF THE INVENTION

[0002]

2. Description of the Related Art Generally, when a sample is analyzed and measured using an X-ray elemental analyzer such as a fluorescent X-ray analyzer, the generation of X-rays from the sample surface is random, and is caused by noise generated in a counting system. Due to fluctuations and the like, statistical fluctuations exist in the X-ray spectrum.

[0003] Statistical error of X-ray measurement values (relative standard error)
Is 1 / n when one count value is n ^1/2It is said that
You. In other words, the relative error decreases as the count value n increases
It indicates that you want to. To increase the count value n, measure for a long time.
Or repeat the measurement and combine the results
Either of the methods is adopted.

Conventionally, operators of X-ray elemental analyzers have
Usually, the intensity of the X-ray excitation source is adjusted by looking at the count rate meter or dead time provided in the apparatus (automatically set devices are increasing). This measurement is performed by estimating the statistical fluctuation value of the required element and setting the required measurement time. In addition, there is an apparatus in which an error range calculated from the statistical fluctuation indicating the reliability of the data is set in the quantitative result.

[0005]

In recent years, X-ray analyzers have been used in the field of quality control and the like, and accordingly, high-level knowledge of analysis has been required without requiring high-level knowledge of analysis. It is required that an accuracy measurement result be obtained. As a mistake that a novice in analysis tends to make, the measurement result may be erroneously determined due to the lack of the aforementioned concept of fluctuation due to statistical fluctuation.
In particular, the fact that there is no concept of significant figures in the launch measurement results and there are many devices that launch the calculated results as they are is one cause of confusion. Further, even if the error range is recorded in the launch measurement result, if the error range is different from the expected value, there is a problem that the measurement must be performed again.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional X-ray elemental analyzer, and it is possible to obtain knowledge on the reliability of measured values without requiring a specialist in analysis. Another object of the present invention is to provide an X-ray elemental analyzer capable of automatically performing analytical measurement with required accuracy.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an X-ray elemental analyzer for detecting X-rays emitted from a sample irradiated with a primary beam and performing analytical measurement of the sample surface. In, means for setting a predetermined region of interest for a measurement spectrum obtained by a short preliminary measurement before starting the main measurement, and means for calculating a statistical error related to the measurement spectrum of the set region of interest, Means for calculating and displaying the expected accuracy with respect to the measurement time that is set based on the calculated statistical error, and calculating and setting the measurement time required to obtain the expected accuracy that is set based on the expected accuracy. And means for performing the following.

As described above, since the apparatus is provided with a means for calculating and displaying the expected accuracy with respect to the measurement time set in advance, it is possible to obtain knowledge on the reliability of the measured value even if it is not an analysis expert. In addition, since there is provided a means for calculating and setting a measurement time required to obtain the expected accuracy previously set based on the expected accuracy, it is possible to easily perform the analytical measurement of the required accuracy.

[0009]

Next, an embodiment will be described. FIG. 1 is a schematic block diagram showing an embodiment of an X-ray elemental analyzer according to the present invention, in which the present invention is applied to a fluorescent X-ray analyzer. In FIG. 1, 1 is an X-ray source composed of an X-ray tube, 2 is a primary X-ray emitted from the X-ray source 1 and irradiated on a sample 3, 4 is a fluorescent X-ray generated from the sample 3, and 5 is a fluorescent X-ray. An X-ray detector (EDS detector) for detecting X-rays; 6 an X-ray counter including a system processor;
Reference numeral 7 denotes a personal computer having an input operation unit 7-1 and a display unit 7-2. The X-ray counter 6 amplifies the electric signal proportional to the energy of the fluorescent X-ray photons detected by the detector 5 in order to obtain a spectrum whose energy is on the horizontal axis, improves the S / N by a filter, and adjusts the AD. Performs conversion and the like. The input operation unit 7-1 can input and set a region of interest (ROI) on a measurement spectrum, expected accuracy, measurement time, and the like. In addition to the qualitative and quantitative analysis functions of the conventional elemental analyzer, It has a function of calculating a statistical error with respect to a measurement spectrum in a specific region, a function of calculating an expected accuracy with respect to an input and set measurement time, a function of calculating a measurement time with respect to an input and set expected accuracy, and the like.

Next, the operation of the X-ray elemental analyzer configured as described above will be described with reference to the flowchart shown in FIG. When an operator starts an analytical measurement using the present apparatus, the operator has a desired expected value for the quantitative analysis accuracy of the target elemental spectrum. Is determined, and the measurement is automatically performed for the measurement time corresponding to the expected accuracy set in advance, and the analysis is performed.

That is, when the measurement mode to be used is selected, first, a preliminary measurement is performed for a short period of time, for example, about 10 seconds, which is previously set from the input operation unit 7-1, and the measured energy spectrum is displayed on the display unit 7-. 2 (step S1). The operator inputs and sets a predetermined region of interest on the energy spectrum from the input operation unit 7-1 by specifying an element according to the periodic table and specifying a spectrum peak using the cursor, and inputs and sets an expected value of the analysis accuracy or a measurement time ( Step S2). Next, an error (1 / n ^1/2 ) due to statistical fluctuation is calculated from the set measured spectrum intensity (count integrated value n) of the region of interest (step S).
3). Then, based on the calculated statistical error, the prediction accuracy with respect to the previously set measurement time is calculated and displayed on the display unit 7-2, and the operator is provided with the judgment information on the measurement time.

When the operator inputs an expected accuracy value with respect to the expected accuracy, a measurement time required for obtaining the input and set expected accuracy is calculated and set based on the calculated expected accuracy (step S4). . In addition, the calculated measurement time is displayed and the operator is asked for confirmation. If the operator does not approve the calculated measurement time and inputs another measurement time, the expected accuracy of the separately input measurement time is considered. Is calculated and displayed. When the set value of the measurement time calculated in the apparatus is approved by the operator, the set measurement time is measured (Step S).
5) A qualitative analysis and a quantitative analysis are performed in a normal procedure (steps S6 and S7). This makes it possible to automatically perform analysis and measurement of a predetermined area with desired expected accuracy.

Table 1 shows an example of calculating the expected spectrum intensity and accuracy (error%) when a predicted measurement time of 600 seconds is input after a preliminary measurement of 10 seconds.

[0014]

[Table 1] Element spectral intensity expected accuracy 14Si 670 3.9 15P 25 20.0 16S 730 3.7 23V 14512 0.8 24Cr 118873 0.3 25Mn 19506 0.7 26Fe 2575039 0.1 28Ni 3089 1.8 29Cu 8 35.4 42Mo 5858 1.3 74W 59220 0.4

From Table 1, for example, for Si, 6
3.9% error expected from statistical fluctuations with a measurement time of 00 seconds
It can be seen that the analytical measurement is performed with an accuracy of 1. On the other hand, when the measurement is performed with an accuracy of 1%, it is understood that the measurement time is required about 9000 seconds.

[0016]

As described above with reference to the embodiments, according to the present invention, there is provided means for calculating and displaying the expected accuracy with respect to the measurement time set in advance, so that an analysis expert Since it is possible to obtain knowledge about the reliability of the measured value without the need, and there is provided a means for calculating and setting the measurement time required to obtain the expected accuracy that is input and set in advance based on the expected accuracy. In addition, it is possible to easily and automatically perform an analysis measurement of required accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an embodiment of an X-ray elemental analyzer according to the present invention.

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

[Explanation of symbols]

 Reference Signs List 1 X-ray source 2 Primary X-ray 3 Sample 4 Fluorescent X-ray 5 X-ray detector 6 X-ray counter 7 Personal computer 7-1 Input operation unit 7-2 Display unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G001 AA01 BA04 CA01 EA03 FA25 GA01 GA03 JA11 JA20 NA07 NA08 NA10 NA11 NA13 NA15 NA17

Claims (1)

[Claims] 1. An X-ray elemental analyzer for detecting and analyzing the surface of a sample by detecting X-rays emitted from the sample irradiated with a primary beam, which is obtained by a short preliminary measurement before starting the main measurement. Means for setting a predetermined region of interest with respect to the measured spectrum obtained, means for calculating a statistical error relating to the measured spectrum of the set region of interest, and estimation of a measurement time input based on the calculated statistical error. X-ray elemental analysis comprising: means for calculating and displaying the accuracy; and means for calculating and setting the measurement time required to obtain the expected accuracy set and input based on the expected accuracy. apparatus.