JPS59169047A - Ion beam mass spectrograph - Google Patents

Abstract

PURPOSE:To perform blanking of ion rays in a mass spectrograph, which is constituted by using two parallel nonmagnetic electrodes and two parallel nonmagnetic electrodes which are perpendicular to the former two electrodes, by changing the voltages of the electrodes so as to make it impossible for ion rays to pass through the hole of a throttle plate according to necessity. CONSTITUTION:Nonmagnetic electrodes 3 and 4 are placed parallel to the traveling direction (optical axis) of ion rays discharged from an ion source. Nonmagnetic electrodes 5 and 6 are placed perpendicular to the electrodes 3 and 4. A throttle plate 8 having a hole 7 on the optical axis of the ion rays, is placed perpendicular to the optical axis in the back of the electrodes 3, 4, 5 and 6. The electrodes 5 and 6 are permanent magnets. By directing a magnetic field (B) toward -x direction, lighter ion rays 1 are more greatly curved than heavy ion rays 2. By applying voltages V and -V to the electrodes 3 and 4 respectively, the ion rays 2 are deflected toward -y direction by means of an electric field (E) and only ion rays 1 passing through the hole 7 can be taken out. In addition, by applying voltage W to either the electrodes 5 or electrodes 6 and earthing the other electrodes, the ion rays 1 and 2 are respectively polarized in directions 1' and 2' and no ions pass through the hole 7 thereby enabling blanking to be performed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a micro ion beam application device, and particularly to a device that requires turning on and off the ion beam onto a sample surface and selecting only a desired ion beam. A mass spectrometer suitable for devices that require irradiation of a sample.

[Prior art]

Mass spectrometers used in micro ion beam application devices have been used only to deposit desired ion beams. Therefore, when it is necessary to turn on and off the ion beam onto the sample surface, it is necessary to insert a separate plunker, and a space is required for this purpose. As a result, there was a drawback that the characteristics of the optical system deteriorated (insufficient mass analysis sensitivity and blanking sensitivity, etc.).

[Purpose of the invention]

An object of the present invention is to provide a mass spectrometer equipped with an ion beam blanking function, thereby saving space for inserting a plunker and providing a high-performance ion optical system.

[Summary of the invention]

A mass spectrometer surrounded by a micro ion beam consists of two parallel non-magnetic electrodes and two parallel magnetic electrodes (mainly permanent magnets) orthogonal to these.

In the present invention, these electrodes are used together as electrodes for a plunker.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

Ion beams emitted from the ion source (for simplicity of explanation, assume that there are two types of ion beams 1.2, and the mass m1 of ion beam 1 is lighter than the mass m2 of ion beam 2. For example, 1 is B
+ ion beam, 2 is like Ni0 ion beam. ), and a non-magnetic electrode 3.4 and a magnetic electrode 5.6 are arranged parallel to the traveling direction (optical axis) as shown in FIG. and vertically.

Now, assuming that the electrode 5.6 is a permanent magnet and the magnetic field B is directed in the -X direction, both ion beams 1 and 2 are deflected in the +y force direction, but since ml<m2, the ion beam 1
can be bent more than ion beam 2. Here, electrode 3.
When voltages V and -V are applied to 4, an electric field E is generated in the -y force direction, and there is a relationship of e: charge (■) = acceleration voltage, the ion beam 1 travels straight as shown in the figure.

On the other hand, the ion beam 2 will be deflected in the -y force direction.

That is, if only the ion beam 1 passing through the hole 7 can be taken out, then K is obtained. This operating principle is well known and is called Wienfilter.

At this time, the electrodes 5.6 are used while being grounded, but in the present invention, a voltage W can be applied to at least one of them. In this embodiment, the electrode 6 is grounded and W is applied to the electrode 5, but it goes without saying that the reverse may be used. At this time, the ion beams 1 and 2 are deflected as 1/ and 2/, and since no ions pass through the hole 7, all of the ion beams are cut. When W=0, that is, in the grounded state, only the desired ion species can be extracted. The same thing can be done even if -W is applied to the electrode 6. It goes without saying that the electrodes 3.4 may also be used. For example, if ■=0, since only B acts, the ion beam is bent by 1°2 in the +y force direction and does not go straight and does not pass through the hole 7, so the ion beam can be cut. In this case, the electrodes 5, 6 are unnecessary, and the same operation can be performed even if, for example, a magnetic field B is created by passing a current through the coil from outside the vacuum. Also, the electrode 3.4°5.
It goes without saying that 6 is not limited to parallel flat plates. For example, it may be circular. Furthermore, in the present invention, it goes without saying that the configuration shown in FIG. 2 may be used. That is, in the case where the permanent magnet of the electrode 5.6 has no conductivity, a separate non-magnetic electrode 10.11 is arranged to
The ion beam may be cut by applying a voltage W to the ion beam.

The present invention includes any configuration in which the ion beam is cut or not cut by applying a voltage to at least one of the electrodes forming the Wien filter or the electrodes separately provided inside the Wien filter. That is, the size and configuration are not limited to those shown in FIGS. 1-2.

〔Effect of the invention〕

According to the present invention, since the mass spectrometer and the plunker can be integrated, space can be saved when configuring the optical system, and optical characteristics can be improved. Furthermore, since sufficient space can be used, the sensitivity of mass spectrometry and the sensitivity of the planker can also be increased.

[Brief explanation of the drawing]

FIG. 1 is a drawing showing the configuration of the present invention and its operating principle. FIG. 2 shows another configuration of the present invention, in which
This shows a cross section of the shaft.

Claims (1)

[Claims] 1. Place two non-magnetic electrodes parallel to the direction of travel of the ion beam (optical axis) and sandwich the ion beam, and place two magnetic electrodes at positions rotated 90 degrees from these electrodes. Furthermore, a diaphragm plate having a hole on the optical axis of the ion beam is placed after the electrode, and the electric field generated by the two non-magnetic electrodes and the magnetic field generated by the two magnetic electrodes are In a Wien mass spectrometer in which only desired ion species are allowed to pass through the aperture hole, the electrode voltage of at least one of the electrodes may be changed to allow all ion beams to pass through the aperture hole as necessary. An ion beam mass spectrometer characterized in that it cannot pass through the hole in the aperture plate.