JPS5973761A - Energy dispersion type x-ray analytical apparatus - Google Patents

Abstract

PURPOSE:To perform calibration with good accuracy within a short time while enhancing the accuracy of the qualitative and quantitative analysis of an element, by providing a selection mechanism for selectively performing permeation, shielding and attenuation actions with respect to X-rays from an X-ray source for calibration. CONSTITUTION:An aluminum material having a known attenuation factor with respect to X-rays is inlaid with a window 14A while anything is not inlaid with a window 14B. To the outside of the mechanism 14, an X-ray source 15 for calibration, for example, a cylindrical member 16 having Fe is arranged. X-rays from the X-ray source 15 for calibration are detected through the window 14B by an X-ray detector 10 and the detected value is compared with a theoretical value to know the calibration value DELTAE of energy. The actually detected X-ray intensity is set as 1B and the window 14A is subsequently positioned to measure intensity IA. The attenuation factor of X-rays due to the window 14A is preliminarily calculated while the calibration value of intensity is calculated from a formula DELTAI=IB.F-IA and the calibration of a measuring system can be accurately and easily performed by using the control knob of constitutional machinery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to an energy-dispersive '4 X-ray analyzer provided with a calibration mechanism.

In recent years, the energy and intensity of the X-rays have been measured by irradiating the surface of a sample with an electron beam, detecting the characteristic X-rays emitted from the sample using an energy-dispersive semiconductor detector, and determining the compositional elements of the sample. Energy dispersive type X that performs qualitative and quantitative analysis of
line equipment has been developed.

Figure 1 shows an outline of the configuration of this energy dispersive X-ray device. In the figure, 1 is an extremely narrow beam of electron beam emitted from an electron source (not shown in the figure). The surface of 2 is irradiated. When the surface of the sample 2 is irradiated with this electron beam flux 1, characteristic X-rays 3 are emitted from that part due to electron transition in the specimen 2 due to the incident electrons. 4 is an X-ray detector made of a silicon semiconductor, and the electric signal from the X-ray detector 4 is amplified by an amplifier 5. 6 is a multi-channel pulse height analyzer;
The high spectrometer 6 is for discriminating the wave height of the output pulse signal from the X-ray detector 4 amplified by the amplifier 5, 7 is an arithmetic controller, and E3 is a display device. In particular, the energy dispersive X-ray analyzer configured as described above
Line detector4. Amplifier 5. If the measurement system M consisting of wave height analysis unit 6 etc. is not adjusted accurately, it will directly affect the accuracy of elemental analysis.For example, if the measurement system M is not adjusted sufficiently,
If a measurement error occurs, it is not possible to accurately perform qualitative analysis to determine the type of element or quantitative analysis to determine the weight concentration of the element. Therefore, when using these analyzers, it is frequently necessary to configure the measurement system M to minimize measurement errors. Incidentally, the calibration of these measuring systems M takes a relatively long time to determine the calibration values, perform the work required for the calibration, and reach a stable state.

Furthermore, the need for these calibrations occurs not only when various component parts are replaced, but also when measurement errors are discovered during analysis. Therefore, if these calibrations can be easily performed in a short time and with high precision, the precision of qualitative and quantitative analysis of elements can be improved, and the analysis time can be shortened.

The present invention has been made in view of the above points. A calibration X-ray source is placed near the calibration X-ray source, and an optical path between the X-ray detector and the calibration X-ray source transmits, shields, and attenuates the X-rays from the calibration X-ray source. It is characterized by the provision of a selection mechanism for selectively performing the action.

The present invention will be explained in detail below using the drawings. FIG. 2 is a cross-sectional view, not showing the vicinity of the X-ray detector, in the seventh embodiment of the present invention, and FIG. FIG. In the figure, 10 is a semiconductor X-ray detector, and the x1! The il detector 10 is located at 9° 12 in a cold 12g tube 11 which is cooled by liquid nitrogen (not shown). The inner cylinder 12 is a protective inner cylinder, and an X-ray entrance window 13 is formed at one end of the inner cylinder 12 . A beryllium film is used in the X-ray entrance window 131J to reduce the attenuation of low-energy X-rays, and also serves to vacuum-seal the inside of the inner tube 12. 14 is a cylindrical mechanism fitted to the outer periphery of one end of the inner cylinder 12. The mechanism 14 has two windows, 14A, 14B, -C;
, Cylindrical parts other than B are XI! The C1 window 14B is made of, for example, lead, which has a high shielding effect against There is nothing fitted into the chamber that allows it to pass through without any attenuation. The mechanism 14
On the outside of the calibration X-ray source 151, for example, t-e/! −
A cylindrical member 16 is arranged on the inner surface of the cylindrical member 16.
is made of a material that has a high shielding effect against X-rays.

, the member 16 is provided with a mechanism 9, for example a gear 16a, which can rotate concentrically outside the mechanism 14. By rotating the gear 17 that meshes with the gear 16a around the shaft 18, the cylinder 6++ +/116' is configured to rotate around its central axis. By rotating the window 14 on the optical path between the calibration X-ray source 15 and the
Either Δ or 14B can be located.

Hereinafter, in an apparatus configured as shown in (G), first, when calibrating the energy axis of the measurement system M, stop the generation of X-rays from the h℃ source and calibrate the A window 14B is arranged, and X-rays from the calibration X-ray source 15 are detected by the X-ray detector 1o via the window 14[3.

The electric signal from the X-ray detector 1'O is input to the pulse height analyzer 6 via the amplifier 5, and the energy (electricity (gF3
) to a voltage value. This result is calculated by the calculation controller 7 and displayed on a display device 8 made of, for example, a CRT. Here, the energy (voltage value) of the X-ray of the calibration X-ray source, e.g. The calibration value of the conine energy △[ can be found by 12th Calibration of the intensity I (J) First, place the window 1413 in the optical path, calibrate the X-ray source 15J, The actually measured X-ray intensity when incident on the detector 10 is assumed to be 18, and then the X-ray detector 1o and the calibration X I!
On the optical path between the il sources 15, there is a window 14. instead of the window 14B. A
Measure the intensity of the detected X-rays at the position UL.

Here, the attenuation rate FIJ due to the window 14 [3 that overlaps with the X-ray e is determined in advance, and the ideal detection strength 11ulF is determined by the following equation.

I B

ΔI=IF-IA=IB・F-IA Once the calibration value ΔF9 for 1 energy and the calibration value ΔI for intensity have been obtained in this way, these calibrations (IJ, ri measurement system M
The measurement system M can be calibrated accurately and easily by calibrating using the adjustment knobs of each of the 174 generators. In addition, when these calibrations are completed and the sample is to be analyzed, select a location other than window 14A and If so,
The calibration X-ray source 15 does not affect sample analysis.

It should be noted that the present invention is not limited to the apparatus of the above embodiments. For example, instead of rotating the calibration X-ray source in J3 around the X-ray detector in the embodiment described in -, The source may be fixed and the mechanism 14 may be moved away from the cylinder 12 and rotated about the central axis of the cylinder 12.

Further, the number of windows formed in the mechanism 14 may be increased so that a plurality of filter members having different X-ray attenuation rates can be used instead of a single filter member. Furthermore, although the calibration in this embodiment is performed using the adjustment knobs of each component of the measurement system M, it may also be performed on the memory of the performance controller 7.

As described above, the present invention makes it possible to accurately and quickly calibrate the measurement system consisting of C′ such as the X-ray detector, amplifier, and pulse height analyzer of an energy dispersive We provide distributed X-ray analysis equipment.

[Brief explanation of the drawing]

Fig. 1 is a (-11 schematic diagram of an I energy dispersion type -x' cross-sectional view. 1: Electrician; 1 bundle; 2: Sample; 3: Characteristic X-ray; 4: X-ray detector; 5: Amplifier; 6: Pulse height analyzer; 7: Arithmetic controller; 8 : display equipment, io: X-ray detector, 11: cooling conduit,
12: Inner cylinder, 13: X-ray entrance window, 14: Cylindrical mechanism, 1
5: Calibration X-ray source, 16: Outer cylinder, 17: Gear, 18: Rotation shaft.

Claims (1)

[Claims] In an X-ray analyzer that analyzes the wave height of an electrical signal obtained from an energy dispersive X-ray detector that detects X-rays from a sample, a calibration X-ray source is placed near the X-ray detector. , a selection mechanism is provided on the optical path between the X-ray detector and the calibration X-ray source for selectively transmitting, shielding, and attenuating the X-rays from the calibration X-ray source. An energy dispersive X-ray analyzer characterized by: