JPS58659B2 - Ion source for mass spectrometer and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an ion source for a mass spectrometer and a method for manufacturing the same.

Conventionally used ion sources for mass spectrometers have been configured into a single unit by interposing spacers for electrically insulating various electrode plates and connecting them with insulated columns.

FIG. 1 and FIG. 2 are views showing an example of this, with FIG. 1 being a front view thereof, and FIG. 2 being a sectional view taken along line AA' in FIG. 1.

In FIG. 1, a sample gas is ionized by electron bombardment in an ionization chamber 1 and extracted by an extraction electrode 2 to produce an ion beam 12.

This ion beam is accelerated and focused by an accelerating electrode 3 and a ground electrode 4, exits from an exit slit 5, and advances inside an analysis tube of a mass spectrometer.

As shown in Figure 2, each of the electrodes and output slits is made of a semicircular non-ferrous steel plate (non-magnetic material) with two mounting holes, and a cutting edge is provided on the opposing sides. was.

1. It is not necessary to apply a voltage to the exit slit 5, but a predetermined voltage is applied to the other electrode plates.

In particular, different voltages can be applied to the left and right electrode plates of the extraction electrode 2, and by adjusting these voltages, the emission direction of the ion beat 12 can be finely adjusted.

Although there are other types of ion sources in which the exit slit 5 is installed separately, the structure and function of the ion source as a whole is the same.

To assemble the above ion source, first insert a threaded metal support 6 into the holes of the ionization chamber 1, the various electrodes 2, 3.4, and the exit slit 5, and then insert the elongated insulator tube 9 into the support.
Insert.

Next, a spacer 8 made of an insulating material having a required height and fitting into the insulator tube 9 is placed between each plate.

An insulating tube T of an appropriate height is placed outside the ionization chamber 1 and the emission slit 5, and is tightened with a nut 11 via a washer 10.

At this time, the centers of the gaps between the blade edges are aligned and the blades are adjusted and assembled so that there is no difference in the level difference between the blade edges.

This ion source is attached to the analysis section of the mass spectrometer using a support column 6.

FIG. 3 is a diagram illustrating the ion optical system for mass spectrometry δ1-.

When the ion beam 12 generated from the ion source travels through an analysis tube (not shown), its trajectory is bent by a magnetic field 13, and it is extracted from a collector slit 16 at the other end of the analysis tube and detected.

The reason why the analytical performance (sensitivity, resolution, M/e range) in a mass spectrometer is achieved as designed is that the relative position of the magnetic field and slit is set according to the theoretical value, and the incident ion beam is when the ion enters the direction of the normal ion orbit 14.

If the ion source is improperly assembled or its installation is improperly adjusted, and the emitted ions pass through the deviated ion trajectory 15, the desired analytical performance cannot be obtained.

In the ion source of the conventional mass spectrometer described above, unless each electrode plate etc. is made to have accurate thickness and parallelism, the slit blade edges will be misaligned and the ion beam will be deflected.

Further, even if the thicknesses of the electrodes and the like are made equal, the dimensions and parallelism of the spacer sandwiched between them must be the same.

In particular, since this spacer is a small annular one with an outer diameter of 10 mm or less, it is necessary to select and assemble spacers with equal parallelism and height on both end surfaces, and this work requires a great deal of effort and experience. It takes.

If the errors between the electrode plate and the spacer accumulate and the difference in level at the slit edge becomes large, it is no longer possible to correct the ion beam exit direction even if you install the entire ion source or adjust the voltage applied to the left and right electrode plates of the extraction electrode. This is because it becomes impossible to do so.

As described above, conventional ion sources require a great deal of expense in machining component parts and assembling and adjusting them.

Also, since the ion source becomes contaminated with sample decomposition products during experiments, it is necessary to remove the ion source and clean it.
．． There must be.

When completely cleaning the ion source, the ion source must be disassembled and reassembled, but it is difficult to reproduce the initial assembly accuracy.

The first aspect of the present invention is to provide an ion source for mass spectrometers that eliminates the drawbacks of the conventional ion sources mentioned above, uses inexpensive parts with little processing, is easy to assemble and adjust, and has high accuracy, and its manufacturing method. It is on offer.

The key point of the present invention is to make various types of compatible electrode plates with accurate shapes from thin stainless steel, to pass an assembly jig through a common hole provided in the electrode plates, etc., and to provide a predetermined space between each electrode plate. A retaining block is inserted to maintain the spacing between the electrode plates, and in this state each electrode plate is fused and fixed using a metal wire and glass as a support.

Directly fixing the electrode plate and glass cannot be directly fused because their expansion coefficients are significantly different. Therefore, it is necessary to weld a metal wire that can be fused to the glass to the electrode and then fuse the metal wire to the glass bar. The ion source is constructed by attaching the ion source, and the jigs and blocks used are then removed.

By doing the above, a compatible, high-precision ion source can be manufactured at low cost, and when the ion source becomes contaminated, it can be replaced as a disposable source to improve experimental efficiency.

Hereinafter, the configuration and manufacturing method of the ion source of the present invention will be explained with reference to the drawings.

FIG. 4 is a front view showing the structure of an ion source according to a first embodiment of the present invention, and FIG. 5 is a sectional view taken along line BB'.

Ionization chamber 2 with a mechanism for generating ions within the protrusion
There is an extraction electrode 22 below 1, which is separated into two pieces to form a slit.

Next, the acceleration electrode 23 and the ground electrode 24 are each a single plate having a hole 29 in the center, and the output slit plate 2
5 is a single plate having a narrow slit hole 30 in the center.

The ionization chamber, various electrode plates, and exit slit plate described above are all made of nonmagnetic stainless steel plates, such as SUS 304.
It is made of a thin plate with a thickness of about 0.2 mm.

Metal wires 27 are welded to each of the above electrode plates, etc.
This metal wire 2T is fused to four glass columns 26 to form one ion source.

The following silk combination is used for the glass type of the glass support 26 and the material of the metal wire 27 due to the relationship between their coefficients of expansion.

For example, there are Fuernico glass and Fuernico alloy wire, hard glass and molybdenum wire, tungsten glass and tungsten wire, etc.

However, this is not limited to the above-mentioned tying; any metal wire or metal plate that can be welded to stainless steel plates and fused to various types of glass can be used to connect and fix electrode plates, etc. and glass columns. be.

Furthermore, - the above-mentioned metal wire is not made of one type of material, but for example, a nickel wire and a Fernico alloy wire are used, which are connected in the middle, and a combination of an electrode plate, a nickel wire, a Fernico alloy wire, and a Fernico glass is used. There is no problem.

A common jig insertion hole 28 is drilled in each of the above-mentioned electrode plates, etc., and an ion beam holder 29 is provided in each electrode plate 23 and 24 except for the ionization chamber 21 and extraction electrode 22, and an ion beam holder 29 is provided in the output slit plate 25. A slit 30 is opened.

In order to make these holes and have the same external dimensions, they must be punched out using a special mold, or they can be precisely made to the same dimensions by printing a predetermined shape and then chemically etching that shape. Since it can be pressurized, products with q-conversion properties can be manufactured.

Since the mold needle of each electrode plate weighs about 1 to 2 g, the metal wire 27 supporting it can be sufficiently supported and fixed with a rigid thin wire having a wire diameter of about 0.51 nm.

In addition, the extraction electrodes 22 are installed separately for safety purposes, applying different voltages to the left and right pole plates, but since each column plate weighs less than 1 g, it can be stabilized sufficiently by fixing them with two metal wires 27. It has been confirmed through experiments that it can be supported.

FIG. 6 is a front view showing a method of assembling and manufacturing the ion source of the present invention using a jig, and FIG. 1 is a plan view thereof.

First, four metal shafts 33 with threads cut at both ends are erected on a metal stand 31.

The outer diameter of this shaft is slightly smaller than the diameter of the hole 28 provided with the ionization chamber, various electrode plates, ionization chambers, etc. of the ion source shown in FIG. 5, and is made so that it can be fitted without wobbling.

Next, the output slit 25 is pushed onto the table 31 through the shaft 33, and one pair of left and right blocks 36 manufactured to have a thickness equal to the distance between the output slit plate and the ground electrode are placed thereon as shown in FIG.

The ground electrode 24 is passed through the shaft of the block 3.
6-Put it on L.

In this way, the block having the same thickness as the various electrode spacings, the various electrode plates, and the ionization chamber are placed, and finally, the holding plate 32 is placed and tightened with the nut 34 through the washer 35.

Since a metal wire 27 is welded to each electrode plate, the glass support 26 is brought close to the metal wire and heated with a small flame to fuse the metal wire and the glass.

At this time, the glass struts 26 may be formed by sequentially connecting each metal wire with softened glass instead of using a glass rod.

Once one ion source is configured as described above, remove the nut 34, washer 35, and presser plate 32, pull out each block 36 laterally, and pull up the ion source holding the glass support 26. The ion source shown in FIGS. 4 and 5 is obtained.

In order to attach the ion source to the analysis tube of a mass spectrometer, for example, a support fitting is attached to the exit slit 25 and the support fitting is fixed inside the analysis tube.

As described above, the ion source of this embodiment includes an ionization chamber, various electrode plates,
Each part of the output sulin l[i] is made with high precision to uniform dimensions, and its assembly method uses jigs, tools, etc., so it can be manufactured with high precision.

In addition, the production cost is low if it is produced to a certain degree.

When this ion source is actually used in a mass spectrometer, there is an open space between the various electrodes, so compared to conventional ion sources, there is no obstruction to the gas passages, resulting in better exhaust efficiency. It also has the advantage of

FIG. 8 is a front view of an ion source which is another embodiment of the present invention;
FIG. 9 is a sectional view taken along line CC' in FIG.

The ion source of this embodiment includes an ionization chamber 21, various electrodes 22.
23, 24 and the exit slit 25 are the same parts as shown in FIG. 4 above, and the ionization chamber to the acceleration electrode is integrated using a jig or the like in the same manner as in the above embodiment.

The components from the accelerating electrode to the exit slit are assembled using the conventional method of insulating slabs, cylindrical plates 8, insulator tubes 9, and columns 6.

The outer diameter of the glass tube 9 is made such that it fits into the holes 28 of the acceleration electrode plate, the earth electrode plate, and the output slit plate without any gaps.

The advantages of the ion source of this embodiment are that the part closest to the ionization chamber that is most likely to be contaminated can be easily replaced, and the ion source is inexpensive with consideration given to cleaning and reuse or disposable replacement of this part.

In the above two embodiments, three or more electrode plates are integrated using a glass support, but for example, only the ionization chamber 21 and the extraction electrode 22 may be integrated, and this part may be easily replaced.

As described above, the present invention manufactures a high-precision, inexpensive ion source for mass spectrometry that can be assembled and adjusted using support members without requiring any skill using an assembly jig by semi-mass-producing interchangeable parts that are uniformly processed. It has a remarkable effect.

Furthermore, by providing the above-mentioned inexpensive ion source, there is also the effect of replacing contaminated parts and improving the experimental efficiency of the mass spectrometer1.

[Brief explanation of the drawing]

Figure 1 is a front view of the ion source of a conventional mass spectrometer. Figure 2 is a sectional view taken along line A-A in Figure 1. Figure 3 is an explanatory diagram of the ion optical system of the mass spectrometer. Figure 4 is an illustration of the ion optical system of the mass spectrometer. 5 is a sectional view taken along line BB' in FIG. 4; FIG. 6 is a front view showing how to assemble the ion source in FIG. 4;
6 is a plan view of FIG. 6, FIG. 8 is a front view of an ion source according to another embodiment of the present invention, and FIG. 9 is a sectional view taken along line c-c' of FIG. 8. Explanation of symbols 1.1, 21...Ionization chamber, 2゜22...Extraction electrode, 3,23...Acceleration electrode, 4゜24... Earth electrode, 5.25・
...Output slit, 6...Post, 7...
...Insulation tube, 8...Spacer, 9...
...Insulator tube, 35.10 ...Washer, 34
゜11...nut, 12...ion beam, 13...magnetic field, 14...regular ion orbit, 15...deviated Ion orbit, 16
...Collector slit, 26...Glass support, 2γ...Metal wire, 28...
Hole, 30...slit, 31...stand,
32... Pressing plate, 33... Shaft, 36.
... Hiring block.

Claims (1)

[Scope of Claims] 1. An ionization chamber that bombards a sample gas with electrons to ionize it, an extraction electrode that takes out the ion beam generated within the ionization chamber, an acceleration electrode and a ground electrode that accelerate and focus the ion beam, and the An ion source for a mass spectrometer comprising an ionization chamber and a support member that electrically insulates and supports the various electrodes, a glass support provided with the support member on the outside of the various electrodes, and a glass support that connects the glass support to the electrode. An ion source for mass spectrometry, comprising: an intermediate member connecting the ion source; 2. An ion source for a mass spectrometer according to claim 1, characterized in that at least two types of small and medium-sized electrode plates for the various electrodes described above are integrated with the glass support and the h-section intermediate member. . 3. In claim 1, the ionization chamber and the various electrode plates are made of stainless steel, and - between the glass support and the stainless steel plate, the glass can be fused and the stainless steel plate can be welded. A mass spectrometry ion source characterized by being integrated through a metal wire. 4. An ionization chamber that bombards the sample gas with electrons to ionize it, an extraction electrode that takes out the ion beam generated within the ionization chamber, an acceleration electrode and a ground electrode that accelerate and focus the ion beam, and electrically connects the various electrodes mentioned above. In a method of manufacturing an ion source for a mass spectrometer, the ion source is equipped with a support member for insulating support, and the various electrodes are maintained at predetermined positions and intervals using a jig and a hire block;
A method of manufacturing an ion source for a mass spectrometer, comprising the steps of constructing an ion source by fusion-bonding glass to an intermediate member pre-welded to the outside of each electrode, and then removing the jig and block.