JPS5814039A - Electronic beam microanalyzer unit - Google Patents

Abstract

PURPOSE:To reliably detect a desired spectral X-rays and to enable to perform a high-precise analysis, by a method wherein each of a primary and a secondary component of spectral X-rays is detected, and an analysis of a sample is conducted based on the ratio of the size of the components to that of the other. CONSTITUTION:The analyzing surface 2a of a sample on a table 1 is scanned by electronic beam 6 from a generating unit 3, and fluoroescence X-rays, irradiated from a sample 2, are separated into spectral components by solar slits 9 and 11. Detectors 22 and 23 are located in series along an advancing direction of spectral X-rays 21 obtained through the slit 11, and a primary and a secondary component of X-rays 21 are individually and simultaneously detected. Detecting outputs D1 and D2 are inputted to crest light discriminating circuits 31 and 32, respectively, and detecting results N1 and N2 are found as N1/N2 by a computing circuit 33. According to the computing results, processing of desired data, such as mapping, on the analysis surfaces 2a takes place.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to snow making using an electron beam macro analyzer, and more specifically, to an electron beam macro analyzer device that can analyze a sample with high measurement accuracy.

For example, to map the elements contained in steel plates, etc.
Conventionally, an X-ray detector has been equipped with a spectroscopic crystal that separates fluorescent X-rays obtained by scanning a sample with an electron beam, and an X-ray detector that detects the X-rays separated by the spectroscopic crystal. A macro analyzer device consisting of:

As shown in FIG. 1, this type of conventional macro analyzer device includes a hole-shaped electron beam generator 3 that scans an analysis surface 2a of a sample 2 placed on a table 1 with an electron beam. There is. A three-piece electron beam generator is configured to focus electrons output from an electron gun 4 using an electron lens 5, and cause the focused electron beam 6 to perform vertical and horizontal scanning according to a current flowing through a deflection coil 7. There is.

When the analysis surface 2a is scanned by the electron beam 6, the fluorescent X-rays 8 emitted from the analysis surface 2a enter the spectroscopic crystal 10 via the solar slit 9, are reflected there, and pass through another solar slit 11. It enters the X-ray detector 12 via the rays and is converted into an electrical pulse signal. The pulse train signal FT from the X-ray detector 12 is input to the pulse height analyzer 14 via the amplifier 13 and subjected to pulse height discrimination, and the pulse height discrimination data D from the pulse height analyzer 14 is sent to the arithmetic circuit 15 and processed. , thereby obtaining analytical data regarding the distribution of the element of interest in the sample.

By the way, an electron beam macro with such a configuration.

In the analyzer device, when the electron beam 6 is swung, the Xm detector 12 The problem is that it is impossible to avoid variations in the amplitude of the electrical signal obtained from the In order to eliminate this problem, generally the ratio of the primary component to the secondary component after the spectroscopy of the fluorescent X-ray of interest output from the X-ray detector 12 is not affected by the above-mentioned imperfection of the solar slit. Taking advantage of this property, fluorescence xm is analyzed using a method called the ratio method. Since the efficiency is low, the detected value of the secondary component is significantly smaller than the detected value of the primary component, and the statistical accuracy of the ratio of the two is significantly lowered, resulting in a problem of lower measurement accuracy. Ta.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electron beam macro analyzer device which eliminates the above-mentioned drawbacks of the prior art and is capable of analyzing samples with high precision.

A feature of the present invention for achieving the above object is that in an electron beam macro analyzer device, fluorescent X-rays emitted from a sample are separated by a spectroscopic crystal and then converted into electrical signals by an X-ray detector. A first detector that detects the primary component of the spectroscopic X-ray and a second detector that detects the secondary component are arranged in series along the incident direction of the spectroscopic X-ray, and the spectroscopic X-ray from the spectroscopic crystal is The primary component and the secondary component of the line are detected separately and simultaneously by a first detector and a second detector, respectively, and the sample is analyzed based on the ratio of the sizes of the detected primary and secondary components. This is what I did.

Using a gas flow type Ar proportional counter as the first detector,
On the other hand, an enclosed type Xs proportional counter can be used as the second detector, and the spectral X-rays pass through the gas flow type Ar proportional counter by penetrating a pair of mylar windows in the gas flow type Ar proportional counter. By inputting the information into the enclosed Xs proportional counter tube, information regarding the primary component and the secondary component of the spectral X-ray can be extracted from each proportional counter tube.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 2 shows an embodiment of an electron beam macro analyzer device according to the present invention. This electron beam macro analyzer device 20 scans the analysis surface 2a of the sample 2 placed on the table 1 with the electron beam 6 from the electron beam generator 3. The point that the fluorescent light Xms is separated by the solar filter 9.11 and the spectroscopic crystal plate 10 is the same as the conventional apparatus shown in FIG.

Therefore, in FIG. 2, the parts corresponding to those in FIG. 1 are given the same reference numerals and their explanations will be omitted.

The electron beam macro analyzer device 20 separately and simultaneously detects the primary component and the secondary component of the spectroscopic X-ray 21 obtained through the solar slit 11. Detector 22 and spectroscopic X-ray 21
The second xm detector 23 detects the secondary component of the spectroscopic
They are arranged in series along the traveling direction of the line 21.

FIG. 3 shows in detail the serial arrangement of the first and second Xm detectors 22,23. The first X-ray detector 22 is a gas flow type Ar proportional counter tube, and a pair of windows 25 and 26 each made of mylar and having a thickness of about 1711 rl are formed in the peripheral wall of its cylindrical casing 24. The pair of windows 25.26 are formed in the peripheral wall of the casing 24 so as to face each other across the central axis.
6 is arranged perpendicular to the traveling direction of the spectral X-rays 21. Therefore, the spectral X-rays 21 can once enter the first X-ray detector 22 through the window 25 and then escape to the outside of the first X-ray detector 22 through the window 26. A second X-ray detector 23 is located behind the first X-ray detector 22.
A beryllium window 28 is disposed in series with the first X-ray detector 22 along the traveling direction of the spectral X-rays 21, and is formed in the peripheral wall of the cylindrical casing 27 of the second X-ray detector 23.
It is provided so as to face the window 26 of the first X-ray detector 22 . Therefore, as described above, the first xm detector 22
The spectral X-rays 21 that have passed through can enter the second X-ray detector 23 via this beryllium window 28 .

The characteristics of the gas flow type Ar proportional counter tube and the enclosed type Xθ proportional counter tube are as shown in Figure 4. The former has high efficiency against low-energy X-rays, and the latter has high efficiency against high-energy X-rays. Is high.

Therefore, for example, if we consider the case of analyzing elements such as manganese in steel sheets, the distribution of X-ray intensity will be as shown in Figure 5. 1st xff) detector 22 which is a tube
On the other hand, each component can be detected with high efficiency by detecting the relatively high-energy secondary components with the second) l detector 23, which is an enclosed X8 proportional meter tube.

Therefore, the output from each X-ray detector 22, 23 is:
D is as shown in FIG. 6, 0, (b). Here, we have explained the case where the element to be analyzed is Mn, but the same applies to other elements as well.
Since the wavelengths of the primary and secondary components of the line are twice as different, it is sufficient to select an effective Xm detector for each component depending on the element of interest.

Returning to Figure 82, in this way each Xm detector 22.2
8. The signal output from 3. After being amplified by the correspondingly provided amplifiers 29 and 30, the wave height discrimination circuit 31.
32, where the intensity of α (n=1) and the intensity of Mn-Ka (n=2) are respectively detected for Mn-. This detection result N1. N, is input to the arithmetic circuit 33, where, in the same way as in the conventional case, both human forces Nl *
The ratio of Nl+ is calculated, and necessary data processing such as mapping of the analysis surface 2a can be performed according to the calculation result.

According to this configuration, each order of the component of the spectral X-ray can be detected with a dedicated X-ray detector and can be detected with high efficiency, so that the value of N+/Nt can be set to an appropriate value. Therefore, it is possible to effectively prevent the value of N from becoming extremely small as in the conventional case. As a result, statistical errors in the values of N and /'tk are reduced, elemental analysis of the sample can be performed with high measurement accuracy, and highly reliable data can be provided.

In the above example, the target X-rays can be detected with high efficiency over a wide range of wavelengths by combining a gas flow type Ar proportional counter tube and an enclosed type Xθ proportional counter tube. The invention is not limited to this combination;
For example, the first and second X-ray detectors may each be a 1m box, and an appropriate combination can be determined depending on the purpose of analysis.

According to the present invention, as described above, desired spectral X-rays can be reliably detected and a sample can be analyzed with high precision, resulting in excellent f''LfC effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional electron beam macro analyzer device, FIG. 2 is a schematic diagram of an electron beam macro analyzer device according to the present invention, and FIG. 3 is a schematic diagram of a conventional electron beam macro analyzer device.
Fig. 4 is a graph showing the characteristics of the Xm detector shown in Fig. 2, Fig. 5 is a graph showing the spectroscopic spectrum of fluorescent X-rays from manganese, (a
) *Figure 6(b) is a graph showing the outputs of the X-ray detectors in Figure 2. 1...Table 2...Sample 6...Electron beam 8...Fluorescent X-ray 1ω...Spectroscopic crystal plate 10-20...'F14 Baby wide beam macro analyzer device 21 Spectral Xm 22 ...First X-ray detector 23 ... Second X-ray detector 31.52 ... Wave height discrimination circuit 33 ... Arithmetic circuit Above 11-

Claims (1)

[Claims] A first detector that detects the primary component of Xa that has been spectrally separated in an electron beam macro analyzer device in which fluorescent X-rays emitted from a sample are spectrally separated by a spectroscopic crystal and then converted into electrical signals by an Xa detector. and a second detector for detecting the secondary component are arranged in series along the incident direction of the spectrum xm, and the primary component and the secondary component of xxg, which are separated by the spectroscopic crystal, are detected by the first detector and the secondary component, respectively. An electron beam macro analyzer equipment characterized by detecting the components separately and simultaneously with a second detector and analyzing the sample based on the ratio of the sizes of the detected primary and secondary components. .