JPS6032308B2 - mass spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mass spectrometer apparatus, and particularly to an analysis tube suitable for use in a high-resolution bear mass spectrometer.

In conventional mass spectrometers, the longitudinal direction of the ion beam (
Ion optical systems that do not have convergence in the NS direction of the magnetic field have been frequently used.

However, in recent years, there has been a demand for devices with high resolution and high sensitivity (transmittance from the ion source to the ion collector).
As a countermeasure to this problem, an ion optical system (hereinafter referred to as a three-dimensional convergence type) that also has convergence in the vertical direction has been proposed. In such a device, the desired performance can be achieved if the longitudinal centers of the ion source, field electrode, magnetic field, ion collector, etc. are placed correctly in the same plane, but in reality, This is difficult to achieve due to errors during processing and assembly of each part. Therefore, means are taken to find and set the optimal point by adjusting each necessary part (for example, the ion source, the magnetic field position, the collector slit, etc.). Figure 1 is a plan view of the main parts of such a conventional mass spectrometer, including the S housing, the lightning field 2, and the analysis tube 4.
, the C housing 5 is assembled into an integral Okayama body and fixed to an apparatus pedestal (not shown).

The magnetic field 3 is generated within the air gap (not shown) of the magnetic field 3 and the gap between the analysis tube 4 installed therein (usually about 1 side).
The adjustment is performed by moving the . At this time, the position adjustment of the magnetic field 3 is the most important matter.
Since it is fixed, there are the following drawbacks and inconveniences.

■ In a three-dimensional focusing ion optical system, it is desirable to place the vertical centers of each part on the same plane as described above, but it is particularly difficult to align the center of the magnet cavity with the center of the analysis tube, and as a result, the ion beam Collision with the upper and lower inner walls of the analysis tube, reflection, and scattering occur, resulting in decomposition and a decrease in sensitivity.

■ Naturally, the magnet gap is larger than the outer rectangle of the analytical tube, and if you increase the difference, you can expand the magnet adjustment range, but if you increase the magnet gap, the magnetic field
If the outer rectangle (of course the inner rectangle) of the analysis tube is made smaller, the passage of the ion beam will deteriorate.

An object of the present invention is to provide a mass spectrometer with good ion beam passage by providing flexible connection means at both ends of an analysis tube that penetrates the magnetic field so that the magnetic field and the analysis tube can be moved simultaneously and integrally. It is on offer.

The present invention focuses on the fact that the cause of poor ion beam passage in a mass spectrometer with a stereoscopic focusing ion optical system is the analysis tube, which is the narrowest and longest tunnel in the path. It is designed to have a flexible connection with the fixed part of the magnet, and to be movable simultaneously and integrally with the magnet.

An embodiment of the present invention is shown in FIG.

The S housing 1, the lightning field 2, and the C housing 5 are fixed to an apparatus stand (not shown) in the same manner as in the secondary example, but the analysis tube 4 is connected to the electric fields 2, C through flexible parts 6 at both ends thereof. It is connected to the housing 5. The analysis tube 4 has a thickness (outer rectangle) that matches the air gap of the magnetic field 3, as shown in FIG. According to the movement of the analysis tube 4, the analysis tube 4 can also be moved by the same amount. That is, in contrast to the ideal state in which the center points (or center lines) of the exit slit 7, the exposed field electrode 8, the magnetic field 3, and the entrance slit 9 are located in the same plane in FIG. 4, the manufacturing, assembly, etc. It becomes easier to adjust the magnetic field 3 as a means of correcting unavoidable errors occurring in the process. In the above adjustment, the center plane of the magnetic field 3 and the center line of the analysis tube 4 are aligned so that the ion beam can efficiently pass through the analysis tube 4, which is the narrowest place in the longitudinal direction of the passage of the ion beam 10. Although it is desirable that this be the case, this can be easily achieved in the present invention. As a result, the present invention has the following effects. ■ The center plane of the magnetic field and the center line of the analysis tube are aligned and do not shift even after adjusting the magnetic field.
Collision, reflection, and scattering of the ion beam against the upper and lower inner walls of the analysis tube are reduced, improving sensitivity (ion passing amount) and resolution.

■ Since there is no need for a gap between the magnetic field air gap and the analysis tube, the air gap can be made narrower to increase the magnetic field strength, or the thickness of the analysis tube (and therefore the inner box size) can be increased to allow ions to pass through. to increase the amount;
It can also be used for both.

The relationship between the air gap of the magnetic field 3 and the thickness of the analysis tube 4 can be achieved by fitting each other with appropriate tolerances, or alternatively, the same effect can be obtained by fixing the analysis tube 4 to the magnetic field 3 with no tolerance.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the main parts of a conventional mass spectrometer, FIG. 2 is a plan view of an embodiment of the present invention, and FIG. 3 is a sectional view of the main parts.
FIG. 4 is a schematic diagram for explaining bag adjustment in a mass spectrometer. 1...S housing, 2...Open field, 3...Magnetic field, 4...Analysis tube, 5...C housing, 6
......A beautiful means. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A mass spectrometer in which the magnetic field position can be adjusted,
A mass spectrometer characterized in that the analysis tube section and the magnetic field are configured to move integrally by providing flexible connection means at both ends of the analysis tube section that penetrates the magnetic field. 2. The mass spectrometer according to item 1, wherein the outer rectangle of the analysis tube portion and the air gap of the magnetic field are equal.