CN209963019U - High-efficiency ion source for magnetic mass spectrometer - Google Patents
High-efficiency ion source for magnetic mass spectrometer Download PDFInfo
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- CN209963019U CN209963019U CN201920792041.7U CN201920792041U CN209963019U CN 209963019 U CN209963019 U CN 209963019U CN 201920792041 U CN201920792041 U CN 201920792041U CN 209963019 U CN209963019 U CN 209963019U
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Abstract
The utility model relates to the field of ion sources, and provides a high-efficiency ion source for a magnetic mass spectrometer, which comprises a filament, an ionization box, a repulsion electrode and a deflection plate component; the repulsion electrode is arranged at the front end inside the ionization box, and the repulsion electrode and the ionization box form a cylindrical space together; the filament emits electrons through the cylindrical space to the collector; magnets are arranged outside the ionization box and the collector; the deflection plate assembly comprises a first horizontal deflection lens, a focusing lens, a first vertical deflection lens, a second horizontal deflection lens and a second vertical deflection lens; a slit is provided between the first vertical deflection lens and the second horizontal deflection lens. The utility model realizes two ionization modes of electron bombardment ionization and chemical ionization; differential vacuum is formed inside and outside the ionization box, so that the service life of the filament is prolonged; the ionization chamber and the repulsion electrode form a cylindrical ionization space, and the ion extraction efficiency is high; the repulsion pole and the ionization box have potential difference to form a potential lens, so that the ion space divergence is reduced, and the mass resolution of the instrument is improved.
Description
Technical Field
The utility model relates to an ion source technical field, in particular to a high-efficient ion source for magnetic mass spectrometer.
Background
In recent years, with the development of high-precision machining and electronic techniques, mass spectrometry has been rapidly developed in the fields of chemical engineering and environmental analysis.
Compared with mass spectrometers adopting single photon ultraviolet ionization ion sources and inductively coupled plasma ion sources, the mass spectrometer adopting the electron bombardment ion source has the characteristics of simple structure, abundant types of ionizable samples and high ionization efficiency, and can keep high-efficiency ionization efficiency while realizing the miniaturization of the instrument ion source. The ion extraction device realizes efficient ion extraction, can realize high-precision analysis of an instrument on a sample, and has very important significance for detection of trace substances.
For an ion source used for a magnetic mass spectrometer, a rectangular or cylindrical ionization box is adopted in a traditional electron bombardment ion source, and the space divergence is large after sample ionization, so that the ion extraction efficiency is low after repulsion focusing. The problems to be solved are to realize the high-efficiency ionization of the sample, the selective ionization of the sample and the higher extraction efficiency of the ion beam current.
SUMMERY OF THE UTILITY MODEL
One of the purposes of the utility model is to overcome the defects of the prior art, and to provide a high-efficiency ion source for a magnetic mass spectrometer, which adopts electron bombardment ionization and chemical ionization, and has high ionization efficiency, and forms a potential lens in an ionization box, and the ion extraction efficiency is high.
The utility model adopts the following technical scheme:
a high-efficiency ion source for a magnetic mass spectrometer comprises a filament, an ionization box, a repulsion electrode and a deflection plate component;
the repulsion pole is arranged at the front end in the ionization box, the ionization box and the repulsion pole are respectively provided with a semi-cylindrical shape, and 2 semi-cylindrical shapes jointly form a cylindrical space; the filament for emitting electrons is arranged in the axial direction of the cylindrical space, the filament is arranged outside the ionization box, the collector and the filament are oppositely arranged, and the electrons emitted by the filament penetrate through the cylindrical space in the ionization box through the central small hole to reach the collector; magnets for forming a magnetic field are arranged on the outer sides of the filament and the collector;
the deflection plate assembly comprises a first horizontal deflection lens, a focusing lens, a first vertical deflection lens, a second horizontal deflection lens and a second vertical deflection lens which are arranged in sequence; a slit for ion flow to pass through is arranged between the first vertical deflection lens and the second horizontal deflection lens;
the ionization chamber and the deflector plate assembly are combined into a single unit by a connecting mechanism (the connecting mechanism may be any of the prior art, such as a frame, etc.).
Electrons emitted by the filament enter the ionization box to be ionized with the sample and the auxiliary gas, and ion current is accelerated by the repulsion electrode and shaped by the deflection plate component to form ion beam current for subsequent magnetic mass spectrum separation and analysis.
Applying emission current and acceleration voltage to the filament, wherein the filament emits electrons, and the electrons enter the ionization box through the central small hole and collide with the sample gas in the ionization box for ionization; the ions and the auxiliary gas are chemically ionized to form an ion flow; after the ion flow is accelerated by the repulsion electrode, the ion flow sequentially passes through the first horizontal deflection lens, the focusing lens and the first vertical deflection lens to form a flat strip-shaped ion beam current; and the flat strip-shaped ion beam passes through the slit and is shaped by the second horizontal deflection lens and the second vertical deflection lens to obtain the final ion beam.
Further, the high-efficiency ion source is arranged in the vacuum cavity.
Furthermore, a small central hole between the filament and the ionization box is a differential vacuum hole, so that the vacuum degree of the filament installation position is ensured.
Furthermore, a potential difference is formed between the ionization box and the repulsion electrode, a potential lens is formed in the cylindrical space, the space divergence effect of the ion flow in the ionization area is reduced, and the ion flow is efficiently led out.
Further, the vacuum degree in the vacuum cavity is superior to that in the ionization box.
Further, the first horizontal deflection lens, the focusing lens and the first vertical deflection lens are all electrically insulated from each other by an insulating material.
Further, the second horizontal deflection lens and the second vertical deflection lens are electrically isolated from each other by an insulating material.
The utility model also provides a magnetic mass spectrometer has foretell high-efficient ion source.
The utility model has the advantages that:
1. two ionization modes of electron bombardment ionization and chemical ionization are realized;
2. the ionization chamber and the cylindrical ionization space mode with repulsion are adopted, so that the ionization efficiency is high;
3. in the cylindrical ionization region, a potential lens with a lens shape is formed in the cylindrical ionization region due to the potential difference between the repulsion electrode and the ionization box, so that the ion extraction efficiency is high, and the sensitivity of an instrument is favorably improved;
4. novel structure, simple and reasonable, and wide application prospect.
Drawings
Fig. 1 is a schematic structural diagram of a high-efficiency ion source for a magnetic mass spectrometer according to an embodiment of the present invention.
Fig. 2 is a schematic perspective view of an embodiment of the present invention.
FIG. 3 is a schematic diagram of the cylindrical ionization region inside the ionization chamber.
Fig. 4 is an ion extraction focusing diagram of a high-efficiency ion source for a magnetic mass spectrometer according to an embodiment of the present invention.
FIG. 5 is a schematic diagram showing potential lines of a focusing lens between a repeller and an ionization chamber.
Wherein: 1-an ionization cassette; 2-repulsion polarity; 3-a first horizontal deflection lens; 4-a focusing lens; 5-a first vertical deflection lens; 6-a second horizontal deflection lens; 7-a second vertical deflection lens; 8-a collector; 9-filament.
Detailed Description
Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that technical features or combinations of technical features described in the following embodiments should not be considered as being isolated, and they may be combined with each other to achieve better technical effects.
As shown in fig. 1-3, a high efficiency ion source for a magnetic mass spectrometer according to an embodiment of the present invention includes a filament 9, an ionization chamber 1, a repeller 2, and a deflection plate assembly;
the repulsion electrode 2 is arranged at the front end inside the ionization box 1, the ionization box 1 and the repulsion electrode 2 are both provided with semi-cylindrical shapes, and the semi-cylindrical shapes of the ionization box 1 and the semi-cylindrical shapes of the repulsion electrode 2 form a cylindrical space (a black weighted area in figure 3); the filament 9 for emitting electrons is arranged in the axial direction of the cylindrical space, the filament 9 and the collector 8 are both arranged outside the ionization box 1, the filament 9 and the collector 8 are arranged oppositely and are both positioned on the axis of the cylindrical space, and the electrons emitted by the filament 9 pass through the cylindrical space inside the ionization box 1 through a central small hole to reach the collector 8; magnets for forming a magnetic field are arranged on the outer sides of the filament 9 and the collector 8;
the deflection plate assembly comprises a first horizontal deflection lens 3, a focusing lens 4, a first vertical deflection lens 5, a second horizontal deflection lens 6 and a second vertical deflection lens 7 which are arranged in sequence; a slit for ion flow to pass through is arranged between the first vertical deflection lens 5 and the second horizontal deflection lens 6;
electrons emitted by the filament 9 enter the ionization box 1 to be ionized with the sample and the auxiliary gas, ion current is accelerated by the repulsion electrode 2, the acceleration direction of the ion current is vertical to the axial direction of the cylindrical space, and the ion current is shaped by the deflection plate component to form ion beam current for subsequent magnetic mass spectrum separation and analysis, as shown in fig. 4.
The high-efficiency ion source is arranged in the vacuum cavity. The small central hole between the filament 9 and the ionization box 1 is a differential vacuum hole, so that the vacuum degree of the installation position of the filament 9 is ensured, and the service life of the filament is prolonged.
Preferably, the filament 9, the central aperture and the magnet are coaxial, as shown in fig. 3.
Preferably, the ionization chamber 1 and the repulsion electrode 2 have a potential difference (as shown in fig. 5), a potential lens is formed in the cylindrical space, an ion repulsion electric field is formed, the advantage of low energy divergence is achieved, the spatial divergence effect of the ion flow in the ionization region is reduced, and the ion flow is efficiently extracted. Or, the ionization box 1 and the repulsion electrode 2 have the same electric potential, and the electric field extraction is formed between the ionization box 1 and the deflection plate, so that the high extraction efficiency is achieved.
Preferably, the degree of vacuum in the vacuum chamber is superior to the degree of vacuum in the ionization chamber 1.
Preferably, the first horizontal deflection lens 3, the focusing lens 4 and the first vertical deflection lens 5 are all electrically insulated from each other by an insulating material, for example; the second horizontal deflection lens 6 and the second vertical deflection lens 7 are electrically isolated from each other by an insulating material. The insulating material can be selected from various materials, such as PEEK insulating material.
The working process of the utility model is as follows:
the filament 9, which is arranged at the central aperture position outside the ionization chamber 1, emits electrons, which are focused and pass through the ionization chamber 1 under the action of a magnetic field to reach the collector 8. At the moment, the sample entering the ionization box 1 is ionized under the action of electrons with certain energy; the semi-cylindrical repulsion electrode 2 and the ionization box 1 form a cylindrical ionization region, and ions collide with auxiliary gas to form chemical ionization ions; the ion flow forms a flat band shape after being subjected to repulsion by the repulsion electrode 2, lens focusing and deflection lens action, and enters the mass spectrometer after being accelerated. The ion extraction focusing process of the present invention is shown in fig. 4.
As a specific example: the experiment adopts ES044AEI filament of Kimball Physics company, the current is 2.7 amperes, the voltage is 1.86 volts, and when the electron emission energy is 70 electron volts, the electron current measured by the collector reaches more than 50 nanoamperes. In the experimental process, the intensity of the current emitted by the filament fluctuates in a certain range along with the aging of the filament.
The strength of the selected magnet is influenced by the electron emission energy of the filament. In this embodiment, the intensity of the electron current of the collector 8 reaches a maximum at a magnet intensity of 200 gauss at an electron energy of 70 ev emitted from the filament 9. If the energy of the electrons emitted by the filament 9 changes, the strength of the magnet also needs to be adjusted accordingly.
The innovation of the utility model mainly lies in (but is not limited to):
1. the ion source with the cylindrical ionization region is designed, and the potential lens is formed inside the ion source, so that the spatial divergence effect of ion flow in the ionization region is reduced, the ion flow can be efficiently extracted, and the sensitivity of an instrument is favorably improved;
2. according to the designed ion source with the cylindrical ionization region, a sample and auxiliary gas collide with each other to form chemical ionization, so that the ionization form of the ion source is enriched, and selective ionization of the sample is facilitated;
3. a differential vacuum is formed between the filament and the ionization box through the small central hole, so that the vacuum degree of the filament installation position is ensured, and the service life of the filament is prolonged.
While several embodiments of the present invention have been presented herein, it will be appreciated by those skilled in the art that changes can be made to the embodiments herein without departing from the spirit of the invention. The above-described embodiments are merely exemplary and should not be taken as limiting the scope of the invention.
Claims (8)
1. A high-efficiency ion source for a magnetic mass spectrometer is characterized by comprising a filament, an ionization box, a repulsion electrode, a deflection plate component and a connecting mechanism;
the repulsion pole is arranged at the front end in the ionization box, the ionization box and the repulsion pole are respectively provided with a semi-cylindrical shape, and 2 semi-cylindrical shapes jointly form a cylindrical space; the filament for emitting electrons is arranged in the axial direction of the cylindrical space and is arranged outside the ionization box; the collector is arranged opposite to the filament, and electrons emitted by the filament pass through the cylindrical space in the ionization box through the central small hole to reach the collector; magnets for forming a magnetic field are arranged on the outer sides of the filament and the collector;
the deflection plate assembly comprises a first horizontal deflection lens, a focusing lens, a first vertical deflection lens, a second horizontal deflection lens and a second vertical deflection lens which are arranged in sequence; a slit for ion flow to pass through is arranged between the first vertical deflection lens and the second horizontal deflection lens;
the ionization chamber and the deflection plate assembly are combined into a single body by a connecting mechanism.
2. The high efficiency ion source for a magnetic mass spectrometer of claim 1, wherein the high efficiency ion source is disposed within a vacuum chamber.
3. A high efficiency ion source for a magnetic mass spectrometer as claimed in claim 1, wherein said central aperture is a differential vacuum aperture.
4. The high efficiency ion source for a magnetic mass spectrometer of claim 1, wherein the ionization chamber and the repeller have a potential difference therebetween forming a potential lens within the cylindrical space.
5. The high efficiency ion source for a magnetic mass spectrometer of claim 2, wherein the vacuum within the vacuum chamber is greater than the vacuum within the ionization chamber.
6. The high efficiency ion source for a magnetic mass spectrometer of any of claims 1-5, wherein the first horizontal deflection lens, the focusing lens, and the first vertical deflection lens are all electrically isolated from each other by an insulating material.
7. The high efficiency ion source for a magnetic mass spectrometer of any of claims 1-5, wherein the second horizontal deflection lens and the second vertical deflection lens are electrically isolated from each other by an insulating material.
8. A magnetic mass spectrometer having a high efficiency ion source as claimed in any of claims 1 to 7.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920792041.7U CN209963019U (en) | 2019-05-29 | 2019-05-29 | High-efficiency ion source for magnetic mass spectrometer |
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| CN201920792041.7U CN209963019U (en) | 2019-05-29 | 2019-05-29 | High-efficiency ion source for magnetic mass spectrometer |
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| CN209963019U true CN209963019U (en) | 2020-01-17 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115295396A (en) * | 2022-07-22 | 2022-11-04 | 天津国科医工科技发展有限公司 | Electron bombardment ionization source |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115295396A (en) * | 2022-07-22 | 2022-11-04 | 天津国科医工科技发展有限公司 | Electron bombardment ionization source |
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