JPS5931008B2 - mass spectrometry - Google Patents

Description

[Detailed description of the invention] Technical field of invention The present invention relates to improvements in mass spectrometry.

BACKGROUND OF THE INVENTION Conventionally, mass spectrometers have often been used to ionize a sample gas in a vacuum and perform mass spectrometry on the ions to quantify gas components in the sample.

In this case, ionization is generally performed by emitting thermoelectrons from an ion source and colliding the thermoelectrons with gas molecules.
A conventional mass spectrometer ion source device that performs such ionization is shown in FIG.

In the figure, 1 is filament, 2 is trap, 3, 3' is 1
A pair of permanent magnets, which are placed in a vacuum container. Filament 1 and trap 2 constitute an ion source.
Permanent magnets 3 are provided above and below the ion source, and the polarities of the opposing parts are different.

The sample gas is ionized by colliding with thermionic electrons flowing between the filament 1 and the trap 2, but in this case, the permanent magnet 3
, 3' rotates the thermoelectrons in a spiral shape to increase the efficiency of collision with the gas and promote ionization.

However, light gases such as H2 gas are blown away by the rotation of thermionic electrons, conversely reducing sensitivity and making analysis impossible.

Therefore, when analyzing H2 gas, the permanent magnets 3 and 3' are removed to stop the rotation of thermionic electrons and ionize them, but in this case, it takes time and effort to attach and detach the permanent magnets. There is a problem that the vacuum inside the vacuum container is destroyed each time. OBJECTS OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and it is an object of the present invention to provide a mass spectrometry method that can efficiently and easily analyze various gases while maintaining a vacuum state.

Embodiments of the Invention Embodiments of the invention will now be described with reference to FIGS. 2-4.

In FIG. 2, 11 is a filament, 12 is a trap, and 13 and 13' are a pair of electromagnets.

The electromagnets 13 and 13' are provided above and below the ion source to face each other, and are magnetized so that the polarities of the opposing parts are different. The electromagnets 13|13' are each sealed within a cover 14, 14' of an insulating material such as glass or ceramic. When analyzing gases that are not light, use electromagnet 13.
, 13' are set to 0N, and analysis is performed by giving rotation to the thermionic electrons. When analyzing light gas such as H2 gas, the electromagnet 13
, 13' are set to 0FF for analysis.

Therefore, not only can the conventional effort of attaching and detaching the permanent magnet be saved, but also the problem of breaking the vacuum inside the vacuum container when attaching and detaching the permanent magnet can be solved. In addition, electromagnets 13, 13
' are sealed within the covers 14, 14', so gas generated when the electromagnets 13, 13' are activated will not interfere with the analysis. Next, an example in which H2 gas was actually analyzed by turning the electromagnet ON and OFF will be explained with reference to FIG.

FIG. 3 shows the magnetic field 0FF (electromagnet 13,
This is a mass spectrum of H2 measured at 13'0FF). In the figure, the vertical axis represents the ion amount (peak height), and the horizontal axis represents m/e (mass/number of charges). Furthermore, XlOO, XlO, and Xl represent the sensitivity of the recorder.
Figure 4 shows the spectrum of the mass of H2 when the magnetic field is 0N as a comparative example.
Beak is decreasing. In this way, by setting the electromagnet to 0FF, the peak increases to about 1.8 times that of the 0N state, and the sensitivity improves.

In addition, in the state of magnetic field 0N in Fig. 4, H which is heavier than H2
Due to the increased ionization efficiency of H3, the mass spectrum of H3 (m/e=3), which was not detected in FIG. 3, was measured.

Note that the measurements shown in FIGS. 3 and 4 were performed at a gas pressure of 60 μMHy.

Effects of the Invention According to the present invention, hydrogen analysis in a gas sealed in a reed switch or quantitative analysis of hydrogen gas in a gas used when sealing an IC package in a reducing atmosphere can be easily and accurately performed.

As described above, according to the present invention, there is no need to remove the permanent magnet when analyzing light gases as in the past, and various gases can be analyzed efficiently and easily by simply setting the electromagnet to 0N or 0FF. Moreover, since the electromagnet is sealed with a cover made of insulating material, the gas generated when the electromagnet is activated will not interfere with the analysis.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional mass spectrometer ion source device;
The figure is a front view showing an embodiment of a mass spectrometer ion source device to which the present invention is applied, and Figures 3 and 4 are graphs showing measurement examples by the method of the present invention.
2 is a trub, 13 and 13' are electromagnets, and 14 and 14' are covers.

Claims (1)

[Claims] 1 In mass spectrometry, in which thermionic electrons emitted from an ion source collide with a sample gas to ionize the sample gas, and the ions are subjected to mass spectrometry to quantify the gas components in the sample gas, A pair of electromagnets are sealed in an insulating cover and are excited so that the polarities of opposing parts are different. When analyzing hydrogen gas, the electromagnets are turned off, and when analyzing other gases, the electromagnets are turned off. A mass spectrometry method characterized in that analysis is performed with the electromagnet turned on.