JPS6097606A - Magnet device in mass spectrometer and similar apparatus - Google Patents

Abstract

PURPOSE:To widen the width of an ion beam pass in an analysis portion and improve sensitivity and resolving power by sealing the space of a pole piece with non-magnetic material, using the pole piece in place of an analysis pipe and removing the analysis pipe. CONSTITUTION:The space of pole pieces 2 which are arranged facing to each other is fixed hermetically at the both ends of a vacuum container 6 of non-magnetic material and the vacuum container 6 is connected to an electric field housing 4 and a collector housing 5 with a flexible part 7 at the inlet and the outlet of an ion beam. The ion beam passes through the electric field housing 4, the flexible part 7, the space of the pole pieces 2, the flexible part 7 and the collector housing 5. Consequently, the space of the pole pieces itself can be used for the width of ion beam path. By this method, the width of ion beam path can be widened, e.g., from the existing 6-10mm. and the permeability of the ion beam is enhanced resulting in the improvement in the sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnet device for a mass spectrometer, and particularly to a magnet device for use in a high-sensitivity, high-resolution mass spectrometer.

[Background of the invention]

Conventionally, in mass spectrometers, ion optical systems that do not have the ability to focus the ion beam in the longitudinal direction (the NS direction of the magnet) have been frequently used. In recent years, devices with high resolution and high sensitivity, so-called devices with high transmittance from the ion source to the collector, have been developed, and as a countermeasure to this problem, ion optical systems having convergence also in the vertical direction are being considered.

However, since there is a limit to converging the ion beam in the vertical direction, collisions with the upper and lower inner walls of the analysis tube, reflection, scattering, etc. occur in the analysis tube, which is a narrow and long tunnel in the vertical direction, resulting in a decrease in sensitivity. This resulted in a decrease in resolution. Therefore, increasing the vertical width of this analysis tube will naturally improve sensitivity and resolution, but since the magnet gap will naturally also become wider, the magnetic field strength will become weaker, which narrows the range of ion mass numbers that can be measured. The disadvantage is that the Therefore, when emphasis is placed on sensitivity and resolution, methods have been adopted, such as increasing the vertical width of the analysis tube to narrow the measurement mass range, or sacrificing sensitivity and resolution by decreasing the vertical width of the tube.

[Purpose of the invention]

An object of the present invention is to provide a mass spectrometer in which the width of the analysis section can be increased by removing the analysis tube and the ion beam can pass through the mass spectrometer.

[Summary of the invention]

In the present invention, in a mass spectrometer, the cause of poor passage of the ion beam is detected in the path (ion source → electric field → analysis unit →
Detection section) Focusing on the fact that the tunnel in the analysis section is the narrowest and longest tunnel in the vertical direction, we focused on the problem and solved this problem by sealing the gap in the pole piece with a non-magnetic material and using the pole piece as the analysis tube. There is a particular thing.

[Embodiments of the invention]

FIG. 1 shows a conventional analysis section using an analysis tube.

The analysis tube 3 is attached to the gap between the pole pieces 2 (N and S poles), and the pole pieces 2 are attached to the yoke 1.

Also, both ends of the analysis tube 3 are connected to the electric field/%Using 4 and the collector I.
- Attached to Uzing 5.

Ions emitted from the ion source become an ion beam and pass through the electric field section 4 -> analysis tube 3 -> collector nousing 5 and reach the ion detector. As is clear from the figure, the narrowest part in the vertical direction is the analysis tube 3, and even if the gap between the pole pieces 2 is set to 10 m, for example, the thickness of the analysis tube 3 is 1 country, 1 analysis tube 3 and the pole piece. If we consider the gap of 2 to be 1 gap, the width that the ion beam can pass through is only 6 parrots.

-1 In FIG. 2 of an embodiment of the present invention, the gap portions of pole pieces 2 arranged opposite to each other are vacuum-tightly fixed from both ends of a vacuum container 6 made of a non-magnetic material. is connected to the electric field housing 4 and the collector/S magnifier 5 via a flexible part 7 at its ion beam entrance/exit. The ion beam passes through the electric field/S-shaped jig 4 → the flexible part 7 → the gap of the pole piece 2 → the flexible part 7 → the C housing 5. Therefore, the gap in the pole piece itself can be used as the passage width of the ion beam.

Here, pole piece 2, vacuum container 6. The details of how to attach the flexible component 6 will be explained with reference to FIG. The pole piece 2 is processed into a convex shape, and the convex portions are connected to the vacuum vessel 6 from above and below, respectively.
inserted into. The gap in the pole piece 2 is determined by the vertical width of the vacuum container 6 and the length of the curved portion of the pole piece 2. In the present invention, it is set to 10+m+, for example. The contact surface between the vacuum container 6 and the pole piece 2 is sealed by, for example, an O-ring. Flexible parts 7 are attached to both ends of the vacuum container 6 via O-rings or the like. The above-described pole piece 2, vacuum container 6, and flexible component 7 are combined and integrated by a fixing plate 8 made of a non-magnetic material, and then fitted onto the yoke 1.

According to this method, the passage width of the ion beam can be expanded from, for example, the conventional 611II+ to 10 m, and the sensitivity can be improved because the passage of the ion beam is improved. Furthermore, reflection and scattering of ions are reduced, resulting in an improvement in resolution. Furthermore, if the gap in the pole piece 2 is made equivalent to the effective passage width of the ion beam when using a conventional analysis tube, it becomes possible to increase the magnetic field strength and make it possible to measure up to a higher mass number.

〔Effect of the invention〕

According to the present invention, it is possible to widen the ion beam passage width of the six portions without widening the gap in the pole piece, and it is possible to improve sensitivity and resolution.

[Brief explanation of the drawing]

Figure 1 shows a conventional analysis section using an analysis tube, Figure 2
The figure shows the analysis section of the present invention with the analysis tube removed, and FIG. 3 shows a detailed view of the integrated pole piece. DESCRIPTION OF SYMBOLS 1... Yoke, 2... Pole piece, 3... Analysis tube, 4... Electric field housing, 5... Collector housing, 6... Vacuum container, 7... Flexible parts, 8 ...
Fixed plate.

Claims (1)

[Claims] 1. In a magnet device in which a magnetic path is formed by a pole piece and a yoke of a mass spectrometer, the pole piece has a magnetic field generation gap plane and a vacuum seal plane formed in a step-like manner, and the pole piece is 1. A magnet device for a mass spectrometer and similar devices, characterized in that the magnet device is fixedly integrated in a vacuum-tight manner so as to face each other from the upper and lower ends of a magnetic vacuum container, and is fitted into a predetermined position of the yoke to complete a magnetic path. 2. In claim 1, the non-magnetic container has a structure and dimensions to form a necessary magnetic field generation gap when the pole piece is fixed, and a beam exit tube connection port and its connection means are provided on the side surface of the non-magnetic container. Magnet device O for mass spectrometers and similar devices characterized by having