Vacuum feedthrough device for mass spectrometer, processing method and mass spectrometer

Abstract

The invention provides a vacuum feed-through device for a mass spectrometer, a processing method and the mass spectrometer. The vacuum feed-through device comprises a metal electrode, a ceramic plate and a PCB, the ceramic plate is connected to the surface of the PCB; wherein the ceramic plate and the PCB are correspondingly provided with DIP bonding pads; and the metal electrode penetrates through the DIP bonding pad of the ceramic plate and the DIP bonding pad of the PCB and is welded and fixed on the DIP bonding pad. The vacuum feedthrough designed by the invention has the characteristics of low cost, quick processing, flexible design, difficulty in deflation in a vacuum environment and the like. Vacuum feed-through products or schemes for replacing ceramic and glass materials have important significance on instrument research and development and manufacturing cost control and speed improvement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum leak detection, in particular to a simple high-vacuum low-pollution vacuum feedthrough device for mass spectrometers, a processing method and a mass spectrometer. BACKGROUND

[0002] Mass spectrometry is commonly used in the chemical analysis industry, which mainly determines the molecular mass and corresponding ion charge ratio to analyze sample components. The vacuum system is the main component of the mass spectrometer, and the ion source, mass analyzer and detector are all in the vacuum system. For example, the filament that emits electrons in the ion source (such as EI source, CI source) will burn out in the presence of a lot of oxygen, so the filament must work in a high vacuum state. In addition, high vacuum is also conducive to the volatilization of the sample, reducing the interference of the background. During the mass spectrometry process, wherever the sample molecules and ions pass through and exist, it should be pumped to high vacuum. If the internal cavity is not in a vacuum environment, the ions will collide during flight, resulting in changes in the ion flight path or fragmentation, and the mass spectrometer cannot analyze and detect the ions, so the sealing performance of the vacuum cavity plays a key role in the performance of the mass spectrometer.

[0003] The mass spectrometry vacuum cavity needs to introduce and output detection and control signals through the vacuum feedthrough while being sealed. There are several common types of vacuum feedthroughs: 1. Glass-to-metal vacuum feedthrough seals, the crystalline amorphous properties of glass promote low-loss signal transmission, so its performance is good. 2. Ceramic-to-metal vacuum feedthrough seals are a substitute for glass. They have excellent sealing performance in high-stress environments that require robust sealing. 3. Microcrystalline glass metal vacuum feedthrough seals are the best choice for vacuum feedthroughs because they combine the advantages of compression sealing, low signal loss, and excellent performance in high-stress environments. 4. Epoxy resin vacuum feedthrough seals are very economical, but have many limitations, including outgassing issues, and are usually limited to a working temperature of 100 degrees Celsius. 5. Glue or rubber vacuum feedthrough seals are also economical, but have the same limitations as epoxy, and are even more extreme.

[0004] The ion generation and passage system in the mass spectrometry vacuum cavity must be in a high vacuum state, and the ion source vacuum degree should reach 10 -2 ~ 10 -6Pa. The sealing requirements of ion traps are high, and considering the convenience of mass spectrometry evacuation and maintenance, oxygen resin vacuum feedthrough seals and glue or rubber vacuum feedthrough seals are not suitable for use on ion traps. Glass-to-metal vacuum feedthrough seals, ceramic-to-metal vacuum feedthrough seals and microcrystalline glass metal vacuum feedthrough seals have low permeability, which means they can prevent gas permeation. At the same time, their high hardness also makes them have good wear resistance and are more durable for use in vacuum equipment. In addition, ceramic materials also have excellent corrosion resistance and can be used in vacuum environments with special gas requirements. These three vacuum feeds are seals that are often used in vacuum systems, and their sealing performance in a vacuum environment is very good, so their application prospects in vacuum equipment are very broad. But the vacuum feedthroughs made of ceramic and glass materials have high manufacturing costs, and ceramic and glass materials are brittle materials that are easily damaged during use. SUMMARY

[0005] In view of the defects in the prior art, the purpose of the present application is to provide a vacuum feedthrough device for mass spectrometers and a processing method.

[0006] According to the vacuum feedthrough device provided by the present application, the vacuum feedthrough device comprises a metal electrode, a ceramic PCB plate (hereinafter referred to as a ceramic plate) and an FR4 PCB plate (hereinafter referred to as a PCB plate).

[0007] The ceramic plate is connected to the surface of the PCB plate.

[0008] Corresponding DIP pads are provided on the ceramic plate and the PCB plate.

[0009] The metal electrode passes through the DIP pads of the ceramic plate and the PCB plate and is welded and fixed on the DIP pads.

[0010] Further, it further comprises a rubber sealing ring.

[0011] The rubber sealing ring is sleeved on the outer periphery of the ceramic plate.

[0012] Further, it further comprises a first sealing ring.

[0013] The first sealing ring is connected to the surface of the PCB plate.

[0014] The inner diameter of the first sealing ring is larger than the outer diameter of the ceramic plate, and the first sealing ring surrounds the outside of the ceramic plate.

[0015] Further, the inner diameter of the first sealing ring is 0.5±0.05mm larger than the outer diameter of the ceramic plate.

[0016] Further, it further comprises a second sealing ring.

[0017] The second sealing ring is connected to the surface of the PCB board;

[0018] The inner ring size of the second sealing ring is greater than the outer ring size of the first sealing ring, and surrounds the outside of the first sealing ring.

[0019] Further, the first sealing ring and the second sealing ring are formed by etching the copper foil on the surface of the PCB board.

[0020] Further, the width of the first sealing ring and the second sealing ring is one third of the diameter of the rubber sealing ring.

[0021] Further, the ceramic plate is provided with a fixing hole for fixing on the vacuum cavity of the mass spectrometer.

[0022] According to the processing method of the vacuum feedthrough device for the mass spectrometer provided by the application, comprising:

[0023] Step 1: uniformly apply tin paste to the corresponding area of the bottom layer of the ceramic plate and the top layer of the PCB board;

[0024] Step 2: align the ceramic plate and the PCB board by using a plug gauge after pasting, taking the corresponding DIP pads on the ceramic plate and the PCB board as the reference;

[0025] Step 3: place the pasted ceramic plate and the PCB board on a heating platform, and heat to weld the ceramic plate and the PCB board;

[0026] Step 4: insert the metal electrode into the DIP pad of the ceramic plate and the PCB board, and weld it on the DIP pad.

[0027] According to the mass spectrometer provided by the application, the vacuum feedthrough device for the mass spectrometer is included.

[0028] Compared with the prior art, the application has the following beneficial effects:

[0029] The vacuum feedthrough device designed by the application has the characteristics of low cost, rapid processing, flexible design, and is not easy to outgas in a vacuum environment. The ceramic and glass material vacuum feedthrough or scheme has important significance for instrument research and development cost control and speed improvement. BRIEF DESCRIPTION OF DRAWINGS

[0030] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0031] Figure 1 It is a perspective view of the vacuum feedthrough device;

[0032] Figure 2 It is a plan view of the ceramic plate;

[0033] Figure 3 is the plan view of the PCB board;

[0034] Figure 4 is the working spectrum diagram of the medical PAT mass spectrometer to which the vacuum feedthrough of the present application is applied. DETAILED DESCRIPTION

[0035] The present application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present application. These are within the scope of protection of the present application.

[0036] Example 1

[0037] As shown in Figure 1 , a vacuum feedthrough device for mass spectrometer includes: a metal electrode 1, a ceramic plate 2 (ceramic plate PCB board, hereinafter referred to as ceramic plate) fixing hole 3, PCB board 4, DIP pad 5, first sealing ring 6 and second sealing ring 7.

[0038] The ceramic plate 2 is connected to the surface of the PCB board 4, and the ceramic plate 2 and the PCB board 4 are provided with corresponding DIP pads 5, and the metal electrode 1 passes through the DIP pads 5 of the ceramic plate 2 and the PCB board 4 and is welded and fixed on the DIP pads 5.

[0039] The metal electrode 1 is one of the indispensable elements in the mass spectrometry system, responsible for sensing ion movement and converting it into an electrical signal. In order to improve the signal sensitivity and anti-interference ability, high-quality, good-conducting materials are used in the design, and the size and shape are ensured to accurately match the electric field requirements. The surface of the metal electrode 1 is gold-plated, directly connected to the ion trap in the vacuum chamber of the mass spectrometer, used to sense ion movement and convert it into an electrical signal.

[0040] As shown in Figure 2 , the ceramic plate 2 is processed with alumina, which is selected as one of the core components due to its high thermal stability and low expansion coefficient. The stability of this material in harsh environments makes it an ideal choice for the interior of the vacuum chamber. By designing the required number of DIP pads 5 on its surface and ensuring that the hole diameter is 0.1 mm larger than the diameter of the metal electrode 1, it can effectively prevent air leakage and ensure the sealing of the subsequent welding process. The ceramic plate 2 can also be other aluminum substrates, such as PTFE (polytetrafluoroethylene) plate and other chemically stable materials.

[0041] As shown in Figure 3As shown, the PCB board 4 is processed using FR4 copper-clad board material with a standard thickness of 3 mm, and the surface copper thickness is at least 3.5OZ or above. The PCB board 4 surface is not solder-resistant to reduce the risk of contamination. This design ensures that the vacuum feedthrough has a certain toughness, ensuring that the assembly is not easily broken under high pressure. It should be noted that in the PCB industry, 1Oz means that the thickness of the copper with a weight of 1Oz is evenly spread over an area of 1 square foot (FT 2 ). It is expressed in terms of weight per unit area to represent the average thickness of the copper foil. In formula, 1Oz = 28.35g / FT 2 . Specifically, the thickness of 1OZ copper foil is about 35um or 1.35mil.

[0042] The fixing hole 3 is provided on the ceramic plate 2 and is used to be fixed on the vacuum cavity (ion trap wall) of the mass spectrometer. Through accurate positioning and fixing, the stability of the overall structure and signal transmission is ensured.

[0043] The first sealing ring 6 and the second sealing ring 7 are connected to the surface of the PCB board 4 and are formed by etching the copper foil on the surface of the PCB board 4, and the thickness of the copper foil is 3.5OZ or above. The inner diameter of the first sealing ring 6 is 0.5±0.05mm larger than the outer diameter of the ceramic plate 2, and surrounds the outside of the ceramic plate 2. The inner diameter of the second sealing ring 7 is 0.5±0.05mm larger than the outer diameter of the first sealing ring 6, and surrounds the outside of the first sealing ring 6. The outer periphery of the ceramic plate 2 is sleeved with a rubber sealing ring, and the circumference of the rubber sealing ring is slightly smaller than the outer periphery of the ceramic plate 2. The "knife edge" effect formed by the edge of the copper foil can provide a tighter contact sealing effect when the rubber sealing ring is deformed under pressure. The width of the first sealing ring 6 and the second sealing ring 7 is one-third of the diameter of the rubber sealing ring. This structure cooperates with the rubber sealing ring to ensure a stable airtight barrier under high pressure difference, effectively reducing the influence of external pollution on system performance.

[0044] Embodiment 2

[0045] A processing method of a vacuum feedthrough device, comprising:

[0046] Step 1: Use a steel mesh to evenly apply tin paste to the corresponding areas of the bottom layer of the ceramic plate 2 and the top layer of the PCB board 4, and the thickness of the coating is not greater than 0.5mm.

[0047] Step 2: Align the ceramic plate 2 and the PCB board 4 using a plug gauge based on the corresponding DIP pads 5 on the ceramic plate 2 and the PCB board 4, and the bottom layer of the ceramic plate 2 is attached to the top layer of the PCB board 4.

[0048] Step 3: Place the ceramic plate 2 and the PCB plate 4 on the heating welding table, and make the bottom layer of the PCB plate 4 adhere to the heating welding table. Set the temperature of the heating welding table to 280 degrees Celsius and keep it for 3 minutes. After the solder paste is melted, turn off the heating welding table and apply appropriate pressure to the ceramic plate 2 to ensure uniform welding of the ceramic plate 2 and the PCB plate 4, ensuring the sealing performance during operation.

[0049] Step 4: Insert the metal electrode 1 into the DIP pad 5 of the ceramic plate 2 and the PCB plate 4, and use the tin furnace to weld on the DIP pad 5. The temperature of the tin furnace is set to 300 degrees Celsius, and the solder joints on the DIP pad 5 should be uniform and full, without any loose or false soldering that may affect the sealing quality.

[0050] The vacuum feedthrough device described above is not limited to square mass spectrometers, but can also be flexibly adjusted to other geometric shapes such as circular, diamond, and ion trap structures according to the needs, to adapt to different application scenarios. By optimizing material selection and process flow, the vacuum feedthrough component can realize cross-field applications such as environmental monitoring, biological analysis, and industrial detection.

[0051] In actual operation, the application has been tested and verified to provide stable signal transmission under high vacuum, and effectively reduce the influence of external pollution. Through long-term operation data analysis, it is found that the performance of the system remains stable under different application scenarios, and the maintenance cost is low, and the service life is long. The vacuum feedthrough example is applied to a medical PAT mass spectrometer, and the instrument can work effectively. The working spectrum collected is shown in Figure 4 , and there is no abnormality after long-term use.

[0052] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0053] The specific embodiments of the present application have been described above. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A vacuum feedthrough for a mass spectrometer, characterized by, Comprising: a metal electrode (1), a ceramic plate (2) and a PCB plate (4); the ceramic plate (2) is connected to the surface of the PCB plate (4); wherein the ceramic plate (2) and the PCB plate (4) are correspondingly provided with DIP pads (5); the metal electrode (1) passes through the DIP pads (5) of the ceramic plate (2) and the PCB plate (4) and is welded on the DIP pads (5).

2. The vacuum feedthrough for mass spectrometers according to claim 1, characterized in that Further comprising: a rubber sealing ring; the rubber sealing ring is sleeved on the outer periphery of the ceramic plate (2).

3. The vacuum feedthrough for mass spectrometers according to claim 2, characterized in that Further comprising: a first sealing ring (6); the first sealing ring (6) is connected to the surface of the PCB plate (4); the inner diameter of the first sealing ring (6) is larger than the outer diameter of the ceramic plate (2) and surrounds the outside of the ceramic plate (2).

4. The mass spectrometer vacuum feedthrough of claim 3, wherein, The inner diameter of the first sealing ring (6) is larger than the outer diameter of the ceramic plate (2) by 0.5±0.05mm.

5. The vacuum feedthrough for mass spectrometers according to claim 3, characterized in that Further comprising: a second sealing ring (7); the second sealing ring (7) is connected to the surface of the PCB plate (4); the inner diameter of the second sealing ring (7) is larger than the outer diameter of the first sealing ring (6) and surrounds the outside of the first sealing ring (6).

6. The mass spectrometer vacuum feedthrough of claim 5, wherein, The first sealing ring (6) and the second sealing ring (7) are formed by etching copper foil on the surface of the PCB plate (4).

7. The mass spectrometer vacuum feedthrough of claim 5, wherein, The width of the first sealing ring (6) and the second sealing ring (7) is one third of the diameter of the rubber sealing ring.

8. The mass spectrometer vacuum feedthrough of claim 1, wherein, The ceramic plate (2) is provided with a fixing hole (3) for fixing on the vacuum chamber of the mass spectrometer.

9. A method of processing a vacuum feedthrough for a mass spectrometer, characterized by, Comprising: Step 1: evenly apply tin paste to the corresponding areas of the bottom layer of the ceramic plate (2) and the top layer of the PCB plate (4); Step 2: align the ceramic plate (2) and the PCB plate (4) using a plug gauge based on the corresponding DIP pads (5) on the ceramic plate (2) and the PCB plate (4); Step 3: place the aligned ceramic plate (2) and the PCB plate (4) on a heating platform and heat to weld the ceramic plate (2) and the PCB plate (4); Step 4: insert the metal electrode (1) into the DIP pads (5) of the ceramic plate (2) and the PCB plate (4) and weld it on the DIP pads (5).

10. A mass spectrometer, characterized by, The vacuum feedthrough device for mass spectrometer according to any one of claims 1-8.

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