JPH0131661B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inverted dual focus mass spectrometer equipped with a collision dissociation device.

In an inverted double-flux mass spectrometer that performs mass analysis of ions using a magnetic field and then energy analysis using an electric field, a mass spectrum image is formed at an intermediate position between the magnetic and electric fields, so ions are detected between the magnetic and electric fields. By positioning the instrument, it can be used as a single-focusing mass spectrometer, and by positioning a collision chamber at that position, it is also possible to cause collisional dissociation of ions, and the resulting ions are introduced into an electric field for energy analysis. By performing
Information identifying the species ion can be obtained.

As described above, the inverted dual focus mass spectrometer is capable of switching between the three usages, but there has never been a device that can easily switch between these three usages in one operation. The present invention provides a mechanism that allows easy switching between these three usage methods.

The present invention arranges an integrally coupled configuration of an ion detector and a collision chamber so as to be able to slide in a direction perpendicular to the ion beam at an intermediate position between a magnetic field for mass analysis and an electric field for energy analysis. The present invention provides an inverted dual focus mass spectrometer in which sliding can be operated from outside the wall of the vacuum chamber. The present invention will be explained below with reference to Examples.

FIG. 1 shows an entire embodiment of the present invention. I is the ion source, M is the magnetic pole of the electromagnet that forms the magnetic field for mass analysis, E is the electrode that forms the electric field for energy analysis, S1 is the intermediate slit placed between the magnetic field M and the electric field E, and S2 is the two This is the exit slit of a heavy convergence mass spectrometer. A mass spectrum image is formed by the magnetic field M on the intermediate slit S1. D is an ion detector for double focus, ^D1 is an ion detector for single focus mass spectrometry mode, and C is a collision chamber.
The ion detector ^D1 and the collision chamber C are integrally connected and can slide in a direction perpendicular to the ion beam as shown by the arrow in the figure. Collision chamber C
When both the ion detector D1 and the ion detector ^D1 are removed from the path of the ion beam, the device is used as a dual focus mass spectrometer. When the ion detector ^D1 is advanced into the ion beam path, the device is used as a single focusing mass spectrometer. When the collision chamber C is located in the ion beam path, an analysis mode using collisional dissociation of ions is established.

FIG. 2 shows the details of the integrated structure of the ion detector _D1 and the collision chamber C. The ion collision chamber C is a box having an opening n at the front and back through which the ion beam passes, and a collision gas such as He is supplied from the outside. This gas is supplied through a gas supply pipe T from outside the vacuum vessel wall W of the mass spectrometer. Since the collision chamber C is moved in the direction of the arrow, the gas supply pipe T is spirally wound to accommodate this movement. In this embodiment, the ion detector ^D1 is an electron multiplier whose outer tube penetrates the vacuum chamber wall W, and an O-ring P is interposed between the tube and the vacuum chamber wall W to maintain airtightness. It is movable in the direction of the arrow, and serves as a guide for the movement of the integral combination of the collision chamber C and the ion detector ^D1 in the direction of the arrow.

When performing collision dissociation, the collision chamber C is opened at the front and rear openings h.
is positioned so that it is aligned with the intermediate slit S1. Ions of a specific mass that are dispersed by mass in the magnetic field M and pass through the slit S1 enter the collision chamber C and collide with gas molecules supplied from outside, causing collisional dissociation. The energy will be analyzed. Note that the gas supply pipe to the collision chamber C may be passed through the outer cylinder of the ion detector ^D1 , as shown in FIG. 3, and a flexible portion may be provided outside the vacuum. Alternatively, the integral structure of the collision chamber and the ion detector may be airtightly and movably attached to the wall W of the vacuum chamber using a bellows, and may be slid along a separately provided guide.

As described above, in the device of the present invention, the ion detector for singly focused ion detection and the collision chamber are integrally connected, and this integrally connected structure is slid from the outside of the vacuum chamber wall. Switching between the three types of measurement: multiple convergence, single convergence, and collisional dissociation is performed in one operation, and since the collision chamber and ion detector are integrated and slide, the collision chamber on the wall of the vacuum chamber, The ion detector storage space can be designed compactly.

[Brief explanation of drawings]

FIG. 1 is a plan view of an apparatus according to an embodiment of the present invention, and FIG.
The figure is an enlarged plan sectional view of the main part of the same embodiment, and FIG. 3 is a plan sectional view of another embodiment of the main part. I...Ion source, M...Magnetic field for mass spectrometry, S1
...Intermediate slit, E...Electric field for energy analysis, S2...Exit slit, D...Double focusing ion detector, ^D1 ...Single focusing ion detector, C
...Collision chamber, T...Collision gas supply pipe, W...Vacuum chamber wall.

Claims (1)

[Claims] 1. An ion source, a magnetic field for mass spectrometry, and an electric field for energy analysis are arranged in this order, and an ion detection device for single focused ions can be moved in and out of the ion beam path at an intermediate position between the magnetic field for mass spectrometry and the electric field for energy analysis. A structure is provided that integrates the vacuum chamber and a collision chamber for collision dissociation, and this structure is slidable from outside the vacuum chamber wall, making it possible to switch between three measurement modes: single convergence, double convergence, and collision dissociation. A dual convergence mass spectrometer.