A set of acceleration electrodes for acceleration of charged particles in vacuum ion optical system for time-of-flight mass spectrometer

Abstract

An accelerating electrode assembly for accelerating charged particles in a vacuum ion optics system for a time-of-flight mass spectrometer, wherein each accelerating electrode includes a conical portion and at least one elongated leg extending from the conical portion, the elongated leg and any other elongated leg being configured as an electrical connection and mechanical support between the conical portion and a desired potential source.

Description

[Technical Field]

[0001] The present invention relates to a compact time-of-flight mass spectrometer for use in a mass spectrometer for determining the chemical composition of a liquid or gas. [Previous Technology]

[0002] In many areas of industrial applications, there is a need for compact devices to measure the chemical composition of substances in liquid or gaseous form, which can be integrated into production equipment or infrastructure. For example, coating processes used to manufacture semiconductors, optics, and displays require precise process control, which can be achieved by measuring the composition of the gas delivered to the substrate in a vacuum deposition process at high rates (e.g., fractions of a second).

[0003] A mass spectrometer is a high-performance instrument commonly used in laboratories to determine the chemical composition of gases or liquids. A mass spectrometer is an instrument that separates ion beams based on the quotient of substance / charge[1]. A mass spectrometer works by directly measuring positive or negative ions of atoms or molecules of a substance generated inside the instrument's ion source. These ions are then delivered to a mass spectrometer, which obtains a mass spectrum, in which each atomic or molecular species can be identified by the characteristic spectrum of each atomic or molecular species represented on a calibration ruler of mass-to-charge ratio intensity.

[0004] Mass spectrometers can be used to monitor the chemical composition of substances at regular time intervals, and therefore can be used as sensors for process control. Mass spectrometers can exist as instruments that require operator intervention in a laboratory setting, or as autonomous devices that can automatically analyze substances at defined time intervals and provide the results of that analysis to a computer system via a network. Examples of such devices include orifice-entry mass spectrometers (which use small pinholes to transfer gas samples in a vacuum) and membrane-entry mass spectrometers (which use membranes that are semi-permeable to the gas or liquid samples being analyzed).

[0005] There are different methods for separating ions by their mass-to-charge ratio. One method is to use a quadrupole mass filter, which only allows ions with a specific mass-to-charge ratio to pass through and strike the detector. By scanning a certain range of substances, a quadrupole mass spectrometer can generate a mass spectrum. These instruments can be very sensitive, but are relatively slow because mass spectrometry scans need to be performed, which allows them to generate spectra, for example, every 10 seconds or more. Furthermore, to achieve high sensitivity in measurements of samples containing substances present in extremely small or trace amounts (which requires the ability to measure both high and low signals), quadrupole mass spectrometers require gain switching, which is extremely challenging to implement in electronics while ensuring that the instrument's measurements remain quantitative. In addition, their fabrication is challenging because the quadrupole rods require precise mechanical alignment at the micrometer level to achieve the desired performance.

[0006] Another method of separating ions by their mass-to-charge ratio is to accelerate a group of ions from a sample with essentially the same kinetic energy into an ion optics system that guides them toward a detector. Since all ions start with essentially the same kinetic energy but have different masses, the time it takes for them to reach the detector will depend on their mass-to-charge ratio. Therefore, by measuring the time it takes for ions to reach the detector using very fast electronics, a mass spectrum can be obtained; hence, such a device is called a time-of-flight mass spectrometer or mass spectrometer. These instruments are extremely sensitive and fast because they typically operate at a repetition rate of kHz, meaning they acquire thousands of spectra per second and then aggregate them internally in the instrument's electronics to produce a spectrum, for example, every 0.1 or 1 s, which is about ten or even a hundred times faster than a typical quadrupole mass spectrometer. Furthermore, the entire spectrum in a time-of-flight mass spectrometer is acquired using the same gain setting of the detector, allowing for rapid, quantitative, and sensitive measurements. However, these instruments require high-performance electronics, especially when the instrument is compact and the flight time of ions in the analyzer is short (on the order of a few microseconds). Moreover, their performance is highly sensitive to the design details of the ion optics in the analyzer. As a result, time-of-flight mass spectrometers are typically large and expensive instruments, found only in high-end laboratories rather than on-line industrial manufacturing equipment for process control. Therefore, compact size is important to allow for their inline integration into industrial manufacturing equipment. On the other hand, quadrupole mass spectrometers, despite their disadvantages, can be built very small and are therefore commonly used as process control instruments in industry.

[0007] The present invention aims to overcome the aforementioned inconveniences. Therefore, it enables the use of fast time-of-flight mass spectrometers in industrial fields where only quadrupole mass spectrometers were previously used, thereby opening up new possibilities for faster and more sensitive process and product material control in various industrial applications. [Summary of the Invention]

[0008] In a first aspect, the present invention provides a time-of-flight mass spectrometer, the time-of-flight mass spectrometer comprising: a time-of-flight mass spectrometer analyzer; an ion source configured to generate a diverging ion beam; an extraction region configured to orthogonally extract ions from a compensated ion beam into the time-of-flight mass spectrometer analyzer; and a transfer optics disposed between the ion source and the extraction region to compensate for the divergence of the diverging ion beam to generate a compensated ion beam that is substantially parallel or focused near the extraction region.

[0009] In a preferred embodiment, the extraction region includes a push electrode and a pull electrode, which are configured to bend the ion trajectory from the compensation beam by approximately 90 degrees, and an acceleration electrode enables the ions to be accelerated in the direction of the drift region of the time-of-flight mass spectrometer.

[0010] In another preferred embodiment, the transfer optics includes a plurality of electrodes arranged to perform beam guidance to compensate for any of a list including mechanical defects and centrifugal diverging ion beams, to change the direction of the diverging ion beam based on the setting of the voltage applied to the electrodes, and to remove ions from the diverging ion beam that are on diverging trajectories in relation to the focusing capability of the transfer optics.

[0011] In another preferred embodiment, the plurality of electrodes includes: a first plurality of electrodes and a second plurality of electrodes arranged around a diverging ion beam and capable of beam guiding; a third plurality of electrodes and a fourth plurality of electrodes positioned on opposite sides of the ion beam and arranged around approximately half of the diverging ion beam, and capable of changing the direction of the diverging ion beam based on a setting of voltage applied thereto; and a fifth plurality of electrodes configured as interceptors and capable of cutting off ions from the diverging ion beam that are on diverging trajectories in relation to the focusing capability of the optical device.

[0012] In a second aspect, the present invention provides an accelerating electrode assembly for accelerating charged particles in a vacuum ion optical system, wherein each accelerating electrode includes a conical portion and at least one elongated leg extending from the conical portion, the elongated leg and any other elongated leg being configured as an electrical connection and mechanical support between the conical portion and a desired potential source.

[0013] In another preferred embodiment, the electrode assembly further includes an insulating tube configured to sequentially house accelerating electrodes, wherein successive accelerating electrodes have legs of increased length compared to the preceding accelerating electrode in the sequence, and the increased length of the legs is configured to position conical portions at a defined distance between each other to obtain a desired electric field between successive accelerating electrodes, thereby providing a concentric accelerating electrode assembly.

[0014] In another preferred embodiment, the legs of the accelerating electrode are mounted on the same support, which serves as a reference plane.

[0015] In another preferred embodiment, the support on which the electrode assembly is mounted is a printed circuit board.

[0016] In a third aspect, the present invention provides an electrode assembly configured as an accelerating electrode for accelerating ions in an ion optical system or as an electrode for a transmission optical device, each electrode being mechanically fixed and electrically connected to a printed circuit board, wherein the printed circuit board also supports a noise screening program implemented in the vicinity of the mechanically fixed electrode.

[0017] In another preferred embodiment, each electrode is mounted on a printed circuit board by using legs of different lengths than the legs of the other electrodes.

[0018] In another preferred embodiment, at least one subgroup of electrodes is equipped with its own noise screening program.

[0019] In another preferred embodiment, the electrodes are mounted to form a series of aligned electrodes, and each electrode is mounted at an angle relative to the preceding electrode in the sequence.

Implementation Method

[0020] This invention relates to ion optics for time-of-flight mass spectrometers, which improve the manufacturability and performance of time-of-flight mass spectrometers, particularly when there is a focus on compact instruments. Furthermore, it discloses a method for connecting an ion source originally designed for quadrupole mass spectrometers to a time-of-flight mass spectrometer, making it very easy to replace slow quadrupole mass spectrometers used in industrial process control with new, fast time-of-flight mass spectrometers with minimal changes to the existing interface between these measuring instruments and the industrial manufacturing equipment they interface with. All these features allow the use of fast time-of-flight mass spectrometers in industrial applications where only quadrupole mass spectrometers were previously used, thereby opening up new possibilities for faster and more sensitive process and product material control in various areas of industrial applications.

[0021] In one aspect, the present invention relates to an apparatus configured to connect an ion source originally conceived for a quadrupole mass analyzer to a time-of-flight mass spectrometer, which allows for the replacement of a low-performance quadrupole mass filter with a high-performance time-of-flight mass spectrometer with only minimal modifications to the existing instrument, thereby providing great ease of upgrading existing instruments with a faster and more sensitive analyzer.

[0022] Quadrupole mass analyzer technology requires a continuously operating ion source that injects generated ions into the quadrupole analyzer at an angle of several degrees. Hereinafter, we will refer to such a device as a "quadrupole ion source." However, such a divergent ion beam does not allow existing quadrupole ion sources to be docked with time-of-flight mass spectrometers because the resolution is affected when the ions have a velocity component in the direction of ion extraction due to their divergence. Time-of-flight mass spectrometers require nearly parallel ion beams to achieve high-resolution mass spectrometry because the initial time spread of ions in the ion source is crucial for the subsequent separation of passing substances.

[0023] A known technique for docking a continuous ion source (e.g., an electrospray ionization source) with a time-of-flight mass spectrometer is so-called orthogonal extraction, in which ions are introduced into the extraction region of the ion source of the time-of-flight mass spectrometer perpendicular to the extraction direction. Orthogonal extraction allows for the processing of high ion or gas densities from continuous ion sources (e.g., electrospray ionization sources) while preventing the analyzer from operating at excessively high pressures, which poses performance and safety concerns due to the increased risk of discharge between high-pressure components found in time-of-flight mass spectrometers. Operating the analyzer at excessively high pressures reduces the mean free path of ions flying through the analyzer, thereby reducing the sensitivity of the instrument. Another reason for using orthogonal extraction is to measure ions that are too fast to achieve high-quality mass spectrometry with a straight ion source, such as ions in the atmosphere of planetary objects or comets [2][3], because it is not possible to hold such fast ions in a straight ion source and reduce their time spread to achieve good initial conditions for performing high-resolution mass spectrometry analysis.

[0024] This invention discloses a novel orthogonal extraction method that allows the initial diverging ions of a quadrupole ion source to be directed into the extraction region of a time-of-flight analyzer by forming ions into a substantially parallel compensating ion beam, while simultaneously obtaining all the aforementioned advantages of orthogonal extraction ion sources. The invention comprises a combination of: a quadrupole ion source that generates a diverging ion beam; a region in an ion optics device for orthogonally extracting ions into a time-of-flight mass spectrometer; and a transfer optics device placed between the ion source and the extraction region that compensates for the divergence of the ion beam to generate a beam that is nearly parallel or focused near the extraction region.

[0025] The transfer optics are an electrode assembly used to guide the diverging ion beam to the extraction region of the time-of-flight mass spectrometer and form a nearly parallel compensating beam. The electrodes of the transfer optics also act as electrostatic lenses by geometrically focusing ions toward the extraction region.

[0026] Any number of electrodes can be used to achieve the described effect of compensating for beam divergence to a degree sufficient to produce a nearly parallel ion beam that allows the quadrupole ion source to be coupled to the extraction region of the time-of-flight mass spectrometer and to obtain sufficient performance or material resolution. In the preferred embodiment shown in FIG1, the electrode assembly constituting the transfer optics comprises five electrodes labeled 1 to 5. FIG1 depicts a cross-section of the orthogonal ion implantation portion of the ion source of the time-of-flight mass spectrometer. On the right side of FIG1, a quadrupole ion source 100, known from the prior art, is depicted, which provides an ion beam 104. In the center of FIG1, a transfer optics 101, whose electrodes are numbered 1 to 5, can be seen docking the quadrupole ion source 100 to the time-of-flight analyzer (not shown in FIG1). The same digits 1 to 5 appear several times, and the same digits indicate electrodes connected to the same power source. The left side of Figure 1 shows the extraction region, where the ion trajectory is bent approximately 90 degrees by means of a backplate or push electrode 106 and pull electrode 107, and then the ions are accelerated by acceleration electrode 102 along the direction 103 of the field-free drift region of the time-of-flight mass spectrometer. In the middle of Figure 1, the first two electrodes, labeled 1 and 2, surround the ion beam 104 and act as beam guides to compensate for possible geometric deformation of the beam due to mechanical defects or the generation of non-central ions. The third and fourth electrodes, labeled 3 and 4 in Figure 1, surround approximately half of the ion beam 104 and are positioned on opposite sides relative to the ion beam 104, allowing them to be used to change the direction of the ion beam 104 based on their voltage settings. The fifth electrode, labeled 5 in Figure 1, acts as a skimmer by cutting off ions on highly divergent trajectories for the focusing capability of the transmission optics 101. At this point, the ion beam 104 enters the extraction region of the mass spectrometer through aperture 105, which is located at the ground potential of the extraction region. Depending on the actual configuration of the instrument, the actual value of the voltage applied to each of these electrodes may vary. Depending on the polarity of the ions generated by the quadrupole ion source 100, it can be positive or negative, but the voltage applied to these electrodes is typically set in a manner that produces an ion beam 104 having a value on the order of several electron volts (eV). In a preferred embodiment, the potential applied to these electrodes is approximately in the range of -120V to +120V. These electrodes can have any shape that has been proven to produce a beam with the desired characteristics through ion optical simulation (when this can be done using SIMION software) or experimentally. Possible shapes of the electrodes include circular, elliptical, square, and rectangular shapes, or portions thereof.

[0027] When exchanging a quadrupole mass analyzer for a time-of-flight mass spectrometer, the quadrupole ion source that generates a diverging beam is typically not used. Instead, the quadrupole ion source is redesigned to place the region where the neutral gas is ionized (the ionization region) within a confined space between or within the electrodes of the orthogonal section, to immediately accelerate the generated ions and form them into a parallel ion beam. In contrast, despite the disadvantages of quadrupole ion sources that generate diverging ion beams, this invention allows the existing quadrupole ion source to be retained and operated with the time-of-flight analyzer. Surprisingly, the resulting instrument is remarkably stable and high-performance, despite using a component originally optimized for a completely different instrument, namely the quadrupole ion source. Because the ion source is an inherent part of the sample introduction system in existing instruments or products, redesigning this part represents a significant amount of work and risk. In contrast, with this invention, all existing components of the quadrupole ion source and gas introduction system remain unchanged, allowing the instrument to be operated in a familiar manner without altering the interface with the sample introduction system, while providing additional performance that time-of-flight mass spectrometers can offer compared to quadrupole mass analyzers.

[0028] In another aspect, the present invention relates to a device configured to accelerate ions, which is easy to assemble and minimizes capacitive coupling between electrodes, thereby reducing noise (crosstalk) of the high-frequency components of the signal used or intercepted by the device. In a preferred embodiment, the invention allows for reduction of noise caused by the high-voltage pulse generator used to extract ions from the ion source of a time-of-flight mass spectrometer.

[0029] In a time-of-flight mass spectrometer, an electrical pulse is applied to electrodes in an ion source to extract ions from the source by pushing or pulling, or pushing and pulling, and accelerate them to their time-of-flight path for mass spectrometry analysis. When electrodes are used to pull ions, the electrodes can be, for example, a grid, so it must be ensured that ions can pass through it as they are accelerated. Alternatively, electrodes used to pull ions can have different shapes, including holes, but this has some disadvantages in terms of the uniformity of the electric field they produce. The electrical pulse can be a negative or positive pulse, depending on the polarity of the ions produced by the ion source, and typically has a height of several hundred volts and rise and fall times on the order of several nanoseconds. In a particular instrument configuration, more than one electrical pulse can be applied; for example, two electrical pulses can be applied to push and pull ions approximately simultaneously.

[0030] The performance of a time-of-flight mass spectrometer (TOF-MS) depends critically on the steepness and sharpness of the electrical pulse edges. Ideally, the electrical pulse is a perfect square wave. In reality, one or more electrical pulses applied to the ion source of a mass spectrometer typically have a nearly rectangular shape. Since pulses with a near-rectangular shape contain signal components across almost the entire spectrum, the high-frequency portion of the high-voltage pulse can propagate throughout the mass spectrometer, causing noise. The presence of capacitive loads in the ion optics of a TOF-MS analyzer facilitates the propagation of this noise, as capacitors tend to conduct high-frequency signals. This propagation of noise is particularly critical for compact instruments because capacitance is given by the formula C = epsilon * A / d, where epsilon is the dielectric constant of the dielectric between two surfaces, A is the area of ​​the two surfaces, and d is the distance between them. In large instruments, there are large electrodes, but the distance between the electrodes is also large. However, since capacitance is linearly proportional to area but non-linearly proportional to distance, it can be expected that capacitive coupling between adjacent electrodes is more critical for compact instruments, which is one of the reasons why such small devices are difficult to find on the market. Therefore, it is desirable to minimize all capacitive loads in the material analyzer in order to minimize noise and improve the quality of mass spectrometry, especially when focusing on compact ion sources.

[0031] Ion optical systems of time-of-flight mass spectrometers or material analyzers typically comprise a stack of individual electrodes used to create an electric field that accelerates ions introduced into the ion optical system. The electrodes may be metallic electrodes or may be made of other non-conductive materials with a conductive coating. In particular, the accelerating electrodes of the ion source of the ion optical system are typically constructed in this manner. Each of these electrodes is typically shaped as a nearly conical portion 200 with an outer circular crown 201 (see Figure 2) because it is easy to manufacture and assemble in the ion source. Such a design is disclosed, for example, in Figure 15 of [4], and such a design is shown on the left side of Figure 2. Figure 2 depicts two types of electrodes in the accelerating region of a time-of-flight mass spectrometer. On the left side of Figure 2 is a typical design used in such an instrument according to the prior art. On the right side of Figure 2 is a structure according to the invention. In the prior art, these electrodes are formed and stacked on top of each other. Manufacturing and assembly methods include, but are not limited to: mounting the electrodes on a threaded rod and separating them using insulating parts, or directly soldering the electrodes together with a ceramic insulator in between [5][6]. What all these mechanical designs have in common is that each pair of adjacent electrodes forms an approximately parallel surface, similar to a capacitor. This is particularly critical because the accelerating electrode is very close to one or more electrodes of the ion source to which the pulse is applied to extract ions in the time-of-flight path, for example, as shown in Figure 1. Therefore, these parallel surfaces make the instrument more susceptible to picking up the high-frequency components of the noise generated by the one or more pulses applied to the extraction region, and by minimizing the amount of parallel surfaces, as illustrated on the right side of Figure 2, the performance, such as sensitivity, of the time-of-flight mass spectrometer can be significantly improved while maintaining compatibility with manufacturing constraints and meeting the requirements for generating an appropriate electric field to accelerate ions.

[0032] This invention discloses a mechanical design that reduces the inherent capacitance between electrodes while being very easy to assemble. Specifically, the invention allows for the removal of the outer circular crown, such as the outer circular crown 201, typically found in accelerating electrodes used in ion sources of time-of-flight mass spectrometers, thereby reducing the amount of parallel surface and the capacitive load generated by the assembly, while unexpectedly providing a convenient method for assembling such electrodes, particularly for small ion sources or compact instruments. The outer circular crown has no functional role in providing a good electric field, but is found solely in the electrode for ease of fabrication and assembly. According to the invention, such an outer circular crown can be removed and replaced by using an electrode having a nearly conical portion shape 202, as shown on the right side of FIG2, which has at least a thin leg 20 attached. It is understood that each electrode may have one or more legs 203, but two legs are preferred, as shown in the example shown on the right side of FIG2. In FIG2A, an example of an electrode with a single thin leg 203 is shown. Two or more thin legs 203 can be used to increase mechanical stability. Returning to Figure 2, the thin legs 203 serve as mechanical supports for the conical portion 202 and as electrical connections for applying the desired potential to the electrodes. The top circular surface 204 of the conical portion 203 can be open or closed with one or more meshes. A constant or varying potential can be applied to the electrodes. In the case where the electrodes act as extraction electrodes, a high-voltage pulse, as described above, can be applied to them.

[0033] Then, by properly positioning the conical portion 202 of the electrode at an appropriate distance, multiple such electrodes (where the length of the legs 203 increases from one electrode to the other) can be slid into the insulating tube to provide a set of concentric accelerating electrodes, wherein "appropriate" means that the position of such conical portion 202 is determined according to the position of the desired electric field, for example, by simulation of the ion optics of the system. Precise positioning of the conical portion 202 of the electrode can be achieved by using electrode groups with different leg sizes, such that the length of the legs 203 determines the position of the conical portion 202 of the electrode when all electrodes are mounted on the same support serving as a reference plane. This is shown in the example of Figure 2B, where two electrodes with different leg sizes are mounted on the support 300. This concept not only allows for a reduction in the amount of parallel surfaces compared to the conventional practice of having a completely flat surface according to the prior art, but it also unexpectedly leads to a much simpler and faster assembly of this element of the ion optics system, thereby allowing for mass production at very low cost. More specifically, instead of stacking many electrodes and insulators on top of each other, some of which are very small in the case of compact instruments, it is now sufficient to slide the electrode components into the insulating tubes, thus making it very easy to obtain precisely aligned stacked electrode systems.

[0034] In another aspect, the present invention relates to an apparatus for filtering noise that may remain in an ion optics system despite all efforts to reduce noise, such as that described in the previous aspect. Noise can be reduced by applying a noise screening program implemented on a printed circuit board, most effectively, which needs to be as close as possible to the noise source, i.e., as close as possible to the electrodes inside the vacuum chamber of the enclosed time-of-flight mass spectrometer. However, connecting the printed circuit board to the small electrodes of the compact time-of-flight analyzer is a further complication, increasing the complexity of manufacturing and assembly, and thus increasing the cost of the system. Furthermore, it increases the volume of the material analyzer, and thus the volume of the vacuum chamber enclosing the material analyzer, thereby increasing the size and weight of the instrument.

[0035] This invention discloses an integrated design for an accelerating electrode described in the preceding aspects, which uses a printed circuit board as a support 300 (see FIG. 3), as a structural element of the end 301 of the thin leg 203 for attaching the electrode, and as an electrical support for implementing a noise screening program 302. FIG. 3 illustrates this design for a single electrode. FIG. 3 depicts a method of mounting an electrode on a printed circuit board according to the invention, including implementing a noise screening program 302 on the same surface as the mechanical support serving as the electrode.

[0036] By using electrodes with legs of different lengths and by mounting each subsequent electrode at an angle relative to the previous electrode, any number of electrodes can be mounted on the same printed circuit board. Figure 3A shows another example embodiment similar to Figure 2B, comprising two electrodes, wherein each electrode is connected to a corresponding noise screening program 302.

[0037] The present invention, according to the various aspects discussed above, can be used not only for mounting accelerating electrodes but also for mounting extraction electrodes of an ion source, where the extraction electrode of the ion source will be the first stack of electrodes. In a preferred embodiment, all five electrodes of the ion source (one of which is the extraction electrode) are mounted in this manner. Each or selected of these electrodes can be equipped with its own screening program, as implementing a noise screening program in the extraction electrode, except for the extraction electrode to which a pulse is applied, is not very suitable. This allows the noise screening program to be implemented as close as possible to the electrodes of the ion source in a compact time-of-flight mass spectrometer, thereby maximizing the effectiveness of the noise screening program. References

[0038] [1] UPAC. Compendium of Chemical Terminology, 2nd edition. (“Gold Book”). Edited by AD McNaught and A. Wilkinson. Blackwell Scientific, Oxford (1997). XML online corrected version: http: / / goldbook.iupac.org (2006-), created by M. Nic, J. Jirat and B. Kosata; updated by A. Jenkins. ISBN 0-9678550-9-8. https: / / doi.org / 10.1351 / goldbook.

[0039] [2] Balsiger, H., Altwegg, K., Bochsler, P., et al. Rosina – Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, Space Science Review, 128: 745-801, 2007. doi: https: / / doi.org / 10.1007 / s11214-006-8335-3.

[0040] [3] S. Scherer. Design of a high-performance Reflector Time-of-Flight mass spectrometer for space applications. Doctoral dissertation, University of Bern, Switzerland, 1999.

[0041] [4] Balsiger, H., Altwegg, K., Bochsler, P., et al. Rosina-Rostta orbital spectrometer for ion and neutral analysis, Space Science Review, 128: 745-801, 2007. doi: https: / / doi.org / 10.1007 / s11214-006-8335-3.

[0042] [5] Balsiger, H., Altwegg, K., Bochsler, P., et al. Rosina-Rostta orbital spectrometer for ion and neutral analysis, Space Science Review, 128: 745-801, 2007. doi: https: / / doi.org / 10.1007 / s11214-006-8335-3.

[0043] [6] Meyer, S., Tulej, M., Wurz, P., Mass spectrometry of planetary exospheres at high relative velocity: direct comparison of open- and closed-source measurements, Instrumental Methods in Geographic Sciences. Data Systems, 6, 1-8, 2017, doi: https: / / doi.org / 10.5194 / gi-6-1-2017. [Simplified Explanation of the Diagram]

[0045] The invention will be better understood through a detailed description of the preferred embodiments and with reference to the accompanying drawings, wherein:

[0046] FIG1 depicts a cross-section of the orthogonal ion implantation portion of the ion source of a time-of-flight mass spectrometer according to an exemplary embodiment of the present invention;

[0047] Figure 2 depicts two types of electrodes in the acceleration region of a time-of-flight mass spectrometer according to an exemplary embodiment of the present invention;

[0048] FIG2A shows an electrode with a single thin leg according to an exemplary embodiment of the present invention;

[0049] FIG2B shows a plurality of electrodes mounted on a support according to an exemplary embodiment of the present invention;

[0050] Figure 3 depicts a method of mounting electrodes on a printed circuit board according to the present invention; and

[0051] FIG3A shows a plurality of electrodes according to an exemplary embodiment of the present invention, each electrode being similar to the electrode of FIG3, but mounted in a manner similar to that of the electrode in FIG2B. The same reference numerals will be used throughout the drawings and description to indicate the same or similar objects.

Claims

1. An accelerating electrode assembly for accelerating charged particles in a vacuum ion optics system for a time-of-flight mass spectrometer, wherein, Each accelerating electrode includes a conical portion and at least one elongated leg extending from the conical portion. The elongated leg and any other elongated legs are configured as an electrical connection and mechanical support between the conical portion and a intended potential source. The accelerating electrode has elongated legs of different sizes, and the length of the elongated legs determines the position of the conical portion of the accelerating electrode mounted on the same support, which acts as a reference plane. Each accelerating electrode is mechanically fixed and electrically connected to a printed circuit board, which also supports a noise screening process in the vicinity of the mechanical fixation of the accelerating electrode.

2. The accelerating electrode assembly for accelerating charged particles in the vacuum ion optics system for a time-of-flight mass spectrometer as described in claim 1, further includes: An insulating tube is configured to sequentially house an accelerating electrode, wherein each successive accelerating electrode has an elongated leg that is longer than the preceding accelerating electrode in the sequence, and the increased length of the elongated leg is configured to position the conical portion at a predetermined distance between each other to obtain a desired electric field between the successive accelerating electrodes, thereby providing a concentric set of accelerating electrodes.

3. The accelerating electrode assembly for accelerating charged particles in a vacuum ion optics system for a time-of-flight mass spectrometer, as described in claim 1 or 2, wherein, The support on which the accelerating electrode assembly is mounted is a printed circuit board.

4. The accelerating electrode assembly for accelerating charged particles in the vacuum ion optics system for a time-of-flight mass spectrometer, as described in claim 1, wherein, Each accelerating electrode is mounted on the printed circuit board by using slender legs of different lengths than those of the other accelerating electrodes.

5. An accelerating electrode assembly for accelerating charged particles in a vacuum ion optics system for a time-of-flight mass spectrometer, as described in any of claims 1 and 4, wherein, At least one subgroup of the accelerating electrode is equipped with its own noise screening program.

6. An accelerating electrode assembly for accelerating charged particles in a vacuum ion optics system for a time-of-flight mass spectrometer, as described in any of claims 1 and 4, wherein, The accelerating electrodes are mounted to form a sequence of aligned electrodes, with each accelerating electrode mounted at an angle relative to the preceding electrode in the sequence.

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