JPS58196446A - Analysis employing x-rays microanalyzer - Google Patents

Abstract

PURPOSE:To find the existing quantity of elements without the necessity of experienced skill simply by calculating and indicating a concentration value of elements contained in a sample from the ratio between a measured value of intensity of X-rays generated from the sample and the intensity value in the same wavelength derived from a function. CONSTITUTION:When rays 2 irradiates at the specified position on a sample 5, X-rays are generated from the sample 5. But as drive mechanisms 12a, 12b and 12c are controlled under the control of a computer 11, spectral crystals 8a, 8b and 8c scan at a low speed only near the spectrain peak wavelength of a number of elements having individual spectrum peaks within the range of wavelengths which they handle while at a high speed in other wavelengths to measure the intensity of X-rays on a net bases excluding background components in spectrum peak wavelengths of many elements and a detection signal is fed to the computer 11. When the intensity signal of X-rays measured in the spectrum peak wavelength of a certain element is fed thereto, the computer 11 calculates the ratio with the intensity value in the spectrum peak wavelength of an element of 100% concentration derived from a function representing the sensitivity in the detection system used for measurement. This ratio indicates the existing concentration of elements.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for analyzing the presence of elements contained in a sample using an X-ray microanalyzer.

X equipped with multiple spectroscopic crystals that share the spectral range with each other
Using a line microanalyzer, the low-speed sweep angle range of the spectroscopic crystal is set in advance according to the spectral positions of a large number of elements, and the spectrometer is swept under computer control while skipping at high speed except for the preset positions. A method has been used in which the wavelength of X-rays generated when a sample is irradiated with an electron beam is swept at high speed to analyze the elements contained in the sample at the point irradiated with the electron beam. In such conventional methods, X-rays are detected at the spectral peak position of each element by being led to an X-ray detector via a spectroscopic crystal.
The line intensity and the background intensity near this peak position were printed out as they were.

Therefore, in such conventional methods, although extremely fast measurements can be made, the spectroscopic crystal and
A summary of the sensitivity characteristics of each detection system consisting of a line detector, which indicates how much of the element is contained when the detection intensity obtained at the wavelength corresponding to each element. Unless one is a knowledgeable and skilled operator, it is not possible to grasp the approximate concentration of each element from the displayed data.

The present invention was made to solve such conventional problems, and uses an xi microanalyzer that has a plurality of X-ray detection systems each consisting of a spectroscopic crystal and an X-ray detector so that they share the spectral wavelength range. The low-speed sweep angle range of each spectroscopic crystal is set in advance to match the spectral peaks of a large number of elements, and the spectroscopic crystal is swept under computer control while skipping angles other than the set angle range at high speed. □ In a method of analyzing elements contained in a sample from X-rays generated by irradiation, each of the X-ray detection systems irradiates a standard sample with a known concentration with an element that has a spectral peak within its assigned wavelength range. Then, the intensity at the spectral peak of the X-rays generated at that time is measured for each X-ray detection system, and the measured results are used to determine the intensity at each wavelength within the wavelength range shared by each of the X-ray detection systems. A function representing the standard detection intensity is determined and stored, and the concentration value of each element contained in the sample is determined from the ratio of the measured value of the X-ray intensity generated by the sample and the intensity value at the same wavelength derived from the function. This feature is characterized in that it is calculated and displayed.

An embodiment of the present invention will be described in detail below based on the drawings.

Assume that a sample is analyzed using an X-ray microanalyzer equipped with, for example, three detection systems that share the spectral range, as shown in FIG.

That is, in FIG. 1, reference numeral 1 denotes an electron gun, and an electron beam 2 from this electron gun is focused by a focusing lens 4 onto a sample 5 as a thin electron beam. 6X and 6Y are deflection coils for controlling the irradiation position of the electron beam on the sample surface;
A deflection signal is supplied to each of these deflection coils via amplifiers 7X and 7Y, and the electron beam 2 is irradiated to a position designated by this deflection signal. 8a, 8b, and 8c are spectroscopic crystals provided to share the spectral range with each other in order to separate the X-rays generated from the sample, and the X-rays guided through each of these spectroscopic crystals are sent to the detector 9a.

+jb, detected by 9c. These detectors 9a,
The output signals from 9b and 9c are sent to amplifiers 10a and 10b, respectively.
, 10c to the computer 11. This computer 11 has these amplifiers 10a, 10b, 10
In addition to processing the output signal from c, the spectroscopic crystal 8a,
A drive mechanism 12a for moving each of 8b and 8c for wavelength sweeping.

A control signal for controlling 12b and 12C is generated.

13 is a printer or display device for displaying the concentration of elements present in the sample calculated by the computer 11; In addition, in the above-mentioned configuration, the AD converter and D
A converter is omitted.

Now, for each of the three detection systems that share the spectral range, consisting of the spectroscopic crystal 8a and the detector 9a, the spectroscopic crystal 8b and the detector 9b, and the spectroscopic crystal 8C and the detector 9C, in the spectral wavelength range for which it is responsible. The approximate sensitivity is known empirically. Therefore, for each of these detection systems, a large number of 10
When X-rays from an element at a concentration of 0% are detected at each peak wavelength, a curve such as that shown in FIG. 2, which represents how much signal intensity is detected, is used as coefficients a, b.

Select C appropriately, express it in the form of a quadratic function as shown below, and store it in the computer's memory. however,
Z is the wavelength or atomic number.

az2 +bz+c Such a function is calculated for each detection system and for the characteristic
It is created and stored in advance for each of the lines to be detected, the L line, and the 9M line. Next, actually analyze the spectroscopic crystal 8
For the first detection system consisting of a and a detector 9a, at least one standard sample containing a known concentration (for example, 100%) of an element having a spectral peak within this spectral wavelength range is prepared, and this sample is actually subjected to electron injection. Ray 2 is irradiated, and the intensity 11 at the spectral peak wavelength of the X-ray generated at that time, for example, the wavelength indicated by λ1 in FIG. 2, is detected by a first detection system. This signal representing the strong II T 1 is supplied to the monitor 11, and the computer 11 compares this signal strength 11 with the strength 1+' derived from a pre-stored function, and adjusts the function so that the two match. Corrections will be made. This modification is accomplished, for example, by multiplying the function by a constant. Such a calibration of the function representing sensitivity is performed for each detection system when detecting the line, L line, and 1M line as characteristic X-rays. After such calibration of the sensitivity characteristics of each detection system is completed and the function representing the calibrated sensitivity characteristics is stored in the memory of the computer 11, actual measurement of the sample is performed. That is, a predetermined deflection signal is given to the deflection coils 6X and 6Y, and the electron beam 2 is irradiated to a predetermined position on the sample 5. As a result, X-rays are generated from the sample 5, but since the drive mechanisms 12a, 12b, and 12C are controlled by the computer 11, the spectroscopic crystals 8a, 8b, and 8c each have a spectral peak within their assigned wavelength range. Measure the net X-ray intensity excluding background components at the spectral peak wavelengths of many elements by scanning at low speed only in the vicinity of the spectral peak wavelength of the element, for example, and scanning at high speed while skipping other wavelengths. and supplies the detection signal to the computer 11. When the computer 11 is supplied with the X-ray intensity signal measured at the spectral peak wavelength of a certain element, the computer 11 calculates the 100% concentration of the element derived from a function representing the sensitivity of the detection system used for this measurement. The ratio between the intensity value and the intensity value at the spectral peak wavelength is calculated. This ratio indicates the ratio of the actually measured intensity to the intensity at 100% concentration, so this ratio represents the concentration of each element in the sample. For example, It will be displayed as shown in Figure 3.

As described above, according to the present invention, an outline of the concentration of each element contained in a sample can be displayed at high speed, so even an unskilled operator can easily know the abundance of each element.

In the above-described embodiment, in order to obtain a standard function representing the sensitivity of each detection system, functions representing rough characteristics are created and stored in advance, and at least one type of standard sample is prepared for each function of each detection system. were actually measured and the above functions were calibrated using the results. However, for each detection system function, the results of actual measurements on three or more standard samples were used to calibrate the above functions using the method of least squares, etc. The function may be derived and stored.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a device for carrying out the present invention, Fig. 2 is a diagram showing an example of a function representing the sensitivity characteristics of the detection system, and Fig. 3 is a diagram showing an example of a display on a printer. This is a diagram. 1; electron gun, 2; electron beam, 3; focusing lens, 4: b
1 objective lens, 5; sample, 6X, 6Y: deflection coil, 8a
, 8b, 80: spectroscopic crystal, 9a, 9b, 9c: detection 1
．． 11: Ko>Hyug, 12a, 12b. 12C: Drive mechanism, 13; Printer. Patent applicant JEOL Ltd. Representative Tadao Kase Figure 2 yt, f5gi'<6&, 1tLi (%) 3 RE O LU, O YB 15 AL O ER0

Claims (1)

[Claims] Using an X-ray microanalyzer, which has a plurality of X-ray detection systems consisting of a spectroscopic crystal and an X-ray detector so as to share the spectral wavelength range with each other, the low-speed sweep angle range of each of the spectroscopic crystals is adjusted according to the spectral peaks of a large number of elements. is set in advance, and the spectroscopic crystal is swept under computer control while skipping at a high speed except for the set angle range, and the elements contained in the sample are analyzed from the X-rays generated by electron beam irradiation. For each of the X-ray detection systems, a standard sample with a known concentration of an element having a spectral peak within its assigned wavelength range is irradiated with an electron beam, and the intensity of the generated X-ray at the spectral peak is detected by each X-ray detection system. Measurements are made for each system, and the measured results are used to determine and store a function representing the standard detection intensity at each wavelength within the wavelength range shared by each of the X-ray detection systems, and the X-ray intensity generated from the sample is calculated. An analysis method using an X-ray microanalyzer that calculates and displays the concentration value of each element contained in the sample from the ratio of the measured value of and the intensity value at the same wavelength derived from the function.