JPS5933222B2 - gasbunsexouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for performing gas analysis by irradiating a gaseous sample with an electron beam and detecting the resulting X-rays specific to the sample.

Conventionally, gaseous samples have not been analyzed using scanning electron microscopes, etc., but in order to irradiate the sample to be observed and measured with an electron beam, the sample must be placed in a vacuum. It is from.

If a gaseous sample is analyzed using a configuration that uses a concentrated electron beam, such as a scanning electron microscope,
Observation and measurement are carried out by sealing a gaseous sample in a thin-film capsule or by irradiating an electron beam through a thin-film pipe, cutting off ventilation between the sample and the electron beam irradiation section in vacuum. Another method is considered, but in this method, the electron beam is irradiated through the thin film material, so the background of the thin film material affects the measurement results, making it difficult to obtain satisfactory results.
The present invention aims to provide an apparatus that can directly irradiate a gaseous sample with an electron beam without impairing the degree of vacuum in the electron beam irradiation section and measure the X-rays generated thereby.

The gist of the present invention is to provide a nozzle for injecting a sample into an electron beam generation system maintained in a vacuum, and a sample suction tube that opens opposite the nozzle, and to connect the injection nozzle and the suction tube. The purpose is to detect X-rays generated by irradiating the sample jet airflow in the gap with an electron beam from the electron beam generation system.

Next, this will be explained with reference to embodiment figures.

Reference numeral 1 denotes a vacuum chamber wall of an electron beam generation system, and an electron gun, an accelerator, etc. (not shown) are located above an electromagnetic objective lens 2, and a sharply focused electron beam 3 is obtained from these.

The electron beam generation system is connected to an exhaust system 4 to maintain a vacuum. The injection nozzle 6 of the sample introduction tube 5 and the suction port 8 of the sample suction tube T are opened opposite to each other at the focal point of the electron beam 3.
The diameter of the suction port 8 of the suction tube is larger than the opening diameter of the nozzle 6, and both openings are arranged concentrically, so that almost all of the sample sprayed from the nozzle is sucked into the suction port 8 and the exhaust system 9, it has almost no effect on the degree of vacuum within the electron beam generation system. The electron beam 3 is directly irradiated to a location where the sample forms a jet stream 10 between the jet nozzle 6 and the suction port 8 . As a result, X-rays 11 generated from the sample gas are detected and measured by the X-ray detection system 12 to perform gas analysis. In the gas analysis method, which detects the X-rays etc. generated by applying an electron beam to a gaseous sample, it is necessary to maintain a certain degree of vacuum in order to allow the electrons to fly, and the sample gas is also diluted, so the X-rays etc. generated It is also weak, and the sensitivity and accuracy of analysis are low.

In the present invention, since the nozzle and the suction port face each other in a vacuum, even if the sample gas sent to the nozzle is at a high pressure of 1 atmosphere or more, the flow rate of the ejected air flow is high and it diffuses into the vacuum space. Previously, it was sucked into the exhaust pump from the suction port, and a column of high-density gas was created locally in the vacuum, and we irradiated it with a focused electron beam.
This greatly increases the strength of wires, etc. The apparatus of the present invention can be manufactured exclusively for gas analysis, but a scanning electron microscope can also be used.

In this case, it is not necessary to concentrate the electron beam in a small area as when using it as a normal electron microscope, and it is sufficient to focus the electron beam to about 1 md, so by removing the lens aperture, the electron beam current is increased to about 10 -4 A. That is, the present invention expands the capabilities of the electron probe microanalyzer and at the same time provides a new method for gas analysis. Since X-rays excited by electron beams are used, the efficiency of analyzing metal elements in gas is high, and it is also advantageous for continuously analyzing temporal changes in specific elements. Note that since it is larger than a scanning electron microscope, an energy-dispersive X-ray detection system is more advantageous than a wavelength-dispersive X-ray detection system.

[Brief explanation of drawings]

The figure is an explanatory cross-sectional view of the main part of the present invention. 1... Electron beam generation system, 2... Electromagnetic objective lens, 3... Electron beam) 4... Exhaust system, 5... Sample introduction tube, 6... Injection nozzle, 7... Sample suction tube, 8... Suction port, 9... Exhaust system, 10...・・Jet air flow,
11...X-ray, 12...X-ray detection system.

Claims (1)

[Claims] 1 A nozzle that injects a high-pressure sample across the electron convergence point of an electron beam convergence electron optical system surrounded by a vacuum container, and a sample suction tube that opens in close opposition to the nozzle and is connected to an exhaust device are provided. 1. A gas analysis apparatus, characterized in that the electron beam is focused and irradiated onto a high-density jet airflow of a sample in a gap between an injection nozzle and a sample suction tube, and X-rays generated are detected.