Mass spectrometer and method of forming a vacuum system therefor

Abstract

The application provides a mass spectrometer and a forming method of a vacuum system of the mass spectrometer, the mass spectrometer has a gas-tight chamber which is only communicated with an external environment through a vacuum interface, the chamber comprises a first chamber and a second chamber, an adsorption pump is arranged in the second chamber, and the first chamber is communicated with the second chamber through a flow limiting structure. The technical scheme of the application can be applied to a desktop mass spectrometer or even a portable mass spectrometer, and the requirements of the mass spectrometer for low energy consumption, miniaturization and vacuum degree are considered.

Description

Technical Field

[0001] This invention relates to the field of analytical instruments, specifically to a method for forming a mass spectrometer and its vacuum system. Background Technology

[0002] Traditional mass spectrometers are typically used in dedicated testing centers, resulting in large footprints, volumes, and weights. The application of quadrupole technology has reduced the size and weight of mass spectrometers, and with the advent of ion trap technology, designing and manufacturing even lighter mass spectrometers, and even handheld mass spectrometers, has become one of the main directions of current mass spectrometry technology research and development.

[0003] Another factor limiting the lightweight design of mass spectrometers lies in their vacuum systems. Different components of a mass spectrometer have varying vacuum requirements, typically necessitating a multi-stage vacuum system. Furthermore, mass analyzers and detectors usually require high vacuum levels, necessitating both a bulky pre-pump and a continuously operating diffusion pump. Even with relatively small vacuum pumps like molecular pumps, achieving the miniaturization requirements of benchtop mass spectrometers remains challenging. Additionally, portable mass spectrometers place significant demands on the lightweight design of their vacuum systems.

[0004] An adsorption pump is a trapping pump that operates based on the principle of adsorption. It utilizes methods such as chemisorption, cryogenic adsorption, and post-ionization adsorption to create a vacuum environment. Types include getter pumps, ion pumps, and cryogenic pumps. Their size and weight meet the requirements of portable mass spectrometers. However, adsorption pumps have a limited adsorption capacity; once saturated, they cannot continue to adsorb gas. Therefore, they are usually used as auxiliary pumps rather than as the main pump. In practice, a pre-pump pump is required, which increases the size and weight of the vacuum system. Furthermore, the operating and activation pressures of the adsorption pump do not match the operating pressures of components in miniaturized mass spectrometers (such as ion traps, which typically operate at higher pressures than adsorption pumps), hindering the use of adsorption pumps as the main pump in miniaturized mass spectrometers.

[0005] US8829425B1 discloses a technical solution for using a cryogenic pump as the main pump of a portable mass spectrometer. Although the specification briefly introduces a solution for using a getter pump to replace the cryogenic pump to operate the portable mass spectrometer, the cryogenic pump in this patent directly evacuates the chamber where the ion trap is located, and does not provide a solution for matching the difference between the working pressure of the adsorption pump and the working pressure of the ion trap.

[0006] US Patent 5426300A discloses a technical solution using an adsorption pump as the main pump of a portable mass spectrometer. This solution also uses a suction pump to directly evacuate the chamber containing the mass analyzer. However, for ion traps, this mismatch in operating pressure can reduce the lifespan of the suction pump or affect the performance of the ion trap. Summary of the Invention

[0007] To address the above issues, namely how to provide a vacuum system suitable for benchtop or even portable mass spectrometers, taking into account the requirements of such mass spectrometers for low power consumption, miniaturization, and vacuum level, and more accurately matching the vacuum conditions required by the various components of the mass spectrometer, the first aspect of the present invention provides a mass spectrometer having an airtight chamber that is connected to the external environment only through a vacuum interface. The chamber includes a first chamber and a second chamber, the second chamber being equipped with an adsorption pump, and the first chamber and the second chamber being connected through a flow-limiting structure.

[0008] Adsorption pumps are characterized by low energy consumption and miniaturization, but they require activation and a relatively low operating pressure range. The vacuum pressure range they can pump may not match the operating pressure range of some components of the mass spectrometer, such as those that need to operate under low vacuum. According to the mass spectrometer provided by the first aspect of the invention, the adsorption pump is installed in the second chamber, and a flow-limiting structure is provided between the first and second chambers. This allows the operating pressure of the first chamber to be adjusted by configuring or adjusting the opening size of the flow-limiting structure or the flow rate of the vacuum interface (e.g., the sample inlet), ensuring that the pressure of the first chamber is within a pressure range suitable for the operation of its internal components.

[0009] On the other hand, since the first and second chambers are airtight relative to the external environment, as long as the chambers are evacuated to below the activation pressure of the adsorption pump and the adsorption pump is activated before leaving the factory, the activated adsorption pump can meet the load requirements for evacuating the airtight chambers without the need to configure a turbo pump or any other type of large-volume pre-evacuation pump for the vacuum system, which is conducive to the miniaturization and weight reduction of the vacuum system.

[0010] In an optional embodiment of the present invention, an ion trap is provided in the first chamber, and the gas pressure range of the first chamber is P1≥10. -2 Pa.

[0011] The vacuum system of the mass spectrometer provided by the first aspect of the present invention can provide a matching working pressure range for the ion trap, enabling the ion trap to operate in a preferred pressure environment. Moreover, the ion trap can efficiently perform tasks such as ion manipulation, storage, and mass analysis, while its size can meet the size requirements of components in miniaturized mass spectrometers.

[0012] In an optional technical solution of the present invention, an ion optical device, a detector, a mass analyzer and / or an ion source are further provided in the first chamber.

[0013] According to the first aspect of the present invention, the mass spectrometer is provided by concentrating the ion optical device, detector, mass analyzer and / or ion source in the first chamber, that is, the first chamber serves as the main housing of the equipment, while the second chamber, supplemented by a flow-limiting structure, is used to provide a buffer for the gas flow of the vacuum pump. The second chamber can occupy a smaller space while ensuring the gas pressure stability of the first chamber.

[0014] In an optional embodiment of the present invention, the gas pressure in the second chamber is maintained below the activation gas pressure of the adsorption pump.

[0015] According to this technical solution, the gas pressure in the second chamber is kept below the activation gas pressure of the adsorption pump, which can provide and maintain the gas pressure environment required for the activation of the adsorption pump, so that the adsorption pump can adsorb gas molecules in the second chamber. Moreover, the lower gas pressure environment can delay the process of the adsorption pump reaching adsorption saturation, which is beneficial to extending the service life of the adsorption pump.

[0016] In an optional embodiment of the present invention, the adsorption pump is an adsorption pump using an alloy as the adsorption material, and the air pressure range of the second chamber is P2≤10. -2 Pa.

[0017] According to this technical solution, the alloy-material-based gas pump has the advantages of high pumping speed, large gas intake volume, light weight, room temperature gas pumping after activation without the need for power, and can be reused, making it suitable for the miniaturization of mass spectrometers. The gas pressure range of the second chamber is P2≤10. -2 Pa is the air pressure environment suitable for the operation of suction pumps that use alloys as suction materials.

[0018] In an optional technical solution of the present invention, the mass spectrometer further includes a vacuum pump interface connected to the second chamber. The second chamber is connected to an external vacuum pump via the vacuum pump interface, thereby pre-pumping the gas pressure of the second chamber to the activation gas pressure range of the adsorption pump.

[0019] According to this technical solution, the second chamber is pre-evacuated by an external vacuum pump, which helps the gas pressure in the second chamber to quickly reach the required gas pressure environment. After activation, the external vacuum pump can be disconnected, and the power required for the adsorption pump to operate can be maintained by the built-in power supply. This reduces the size of the mass spectrometer, lowers the power consumption and weight of the mass spectrometer, and makes it easier to achieve portability.

[0020] In an optional technical solution of the present invention, the adsorption pump is the main pump of the mass spectrometer.

[0021] According to this technical solution, an adsorption pump is used as the main pump, avoiding the introduction of other larger types of pumps, such as turbo pumps, as the main pump. This reduces the size and weight of the mass spectrometer. Furthermore, the adsorption pump hardly requires an external power supply after activation, thus reducing the power consumption of the mass spectrometer.

[0022] In an optional technical solution of the present invention, a sample introduction device for introducing a gas sample into the first chamber is also included.

[0023] In the optional technical solutions of the present invention, the sample injection device is a gas chromatograph, a capillary sample injection device, or a membrane sample injection device.

[0024] In an optional embodiment of the present invention, the sample introduction device further includes a thermal desorption component. The thermal desorption component is adapted to convert solid or liquid samples into gaseous samples for analysis.

[0025] In the optional technical solutions of the present invention, the mass spectrometer is a compact mass spectrometer.

[0026] In the optional technical solutions of the present invention, the flow limiting structure is a flow limiting orifice, a flow limiting valve, or a flow limiting tube.

[0027] In the optional technical solutions of the present invention, the adsorption pump is one or a combination of multiple of the following: a suction pump, an ion pump, and a cryogenic pump.

[0028] In the optional technical solution of the present invention, the adsorption pump includes a first adsorption pump and a second adsorption pump. The first adsorption pump is an adsorption pump that uses an alloy as the adsorption material, and the second adsorption pump is an ion pump. The adsorption pump is the main pump of the mass spectrometer, and the ion pump is connected to the first chamber or the second chamber.

[0029] According to this technical solution, the ion pump can help remove inert gases that are difficult for the suction pump to adsorb, thereby increasing the types of tests that the mass spectrometer can perform and enhancing the load capacity of the vacuum system.

[0030] In an optional embodiment of the present invention, the adsorption pump includes an ion pump, and the mass spectrometer has a sector magnetic deflection mass analyzer, wherein the sector magnetic deflection mass analyzer and the ion pump share a common magnet. This shared magnet arrangement effectively simplifies the apparatus and reduces its size. In this optional embodiment, the adsorption pump can be a separate ion pump, without including other types of adsorption pumps, to effectively simplify the apparatus while meeting testing requirements.

[0031] The present invention also provides a method for forming a vacuum system of a mass spectrometer. The vacuum system includes a first chamber and a second chamber connected by a flow-limiting structure. An ion trap is disposed in the first chamber, and an adsorption pump is disposed in the second chamber. The method for forming the vacuum system includes the following steps:

[0032] Use an external vacuum pump to evacuate the second chamber until the gas pressure in the second chamber drops to the activation pressure range of the adsorption pump.

[0033] Activate the adsorption pump;

[0034] Start the adsorption pump to reduce the gas pressure in the first chamber to within the working gas pressure range of the ion trap;

[0035] Seal the first and second chambers and disconnect the external vacuum pump. Use an adsorption pump as the main pump of the vacuum system to maintain the vacuum level in the first and second chambers. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the mass spectrometer in the first embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of the mass spectrometer in the second embodiment of the present invention.

[0038] Figure 3 This is a schematic diagram of the mass spectrometer in the third embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram of the mass spectrometer in the fourth embodiment of the present invention.

[0040] Figure 5 This is a flowchart of the method for forming the vacuum system of the mass spectrometer in the fourth embodiment of the present invention.

[0041] Figure label:

[0042] First chamber 1; Second chamber 2; Adsorption pump 3; Flow limiting structure 4; Ion trap 5; Capillary sample introduction device 61; Membrane sample introduction device 62; Vacuum pump interface 7. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] the term

[0045] In this article, the term "adsorption pump" refers to a collection pump that works based on the principle of adsorption. It uses methods such as chemical adsorption, cryogenic adsorption, and post-ionization adsorption to create a vacuum environment, including getter pumps, ion pumps, and cryogenic pumps.

[0046] In this article, the term "getter pump" refers to a chemical adsorption pump composed of getters with a large surface area. The most commonly used are non-evaporable getters (NEG) sintered from alloy materials such as zirconium vanadium iron alloy. After activation (heating in a vacuum), it can absorb various reactive gases, such as hydrogen, oxygen, water, carbon monoxide, carbon dioxide, and nitrogen, through three processes: surface adsorption, surface dissociation, and bulk diffusion.

[0047] In this article, the term "compact mass spectrometer" refers to a mass spectrometer whose size, volume, weight, and power consumption are significantly smaller than those of a conventional laboratory mass spectrometer. It is small, benchtop, or portable in size; and weighs less than 20 kg.

[0048] [First Implementation Method]

[0049] Please see Figure 1 As shown, this embodiment provides a compact mass spectrometer with an airtight chamber that is connected to the external environment only through a vacuum interface. The vacuum interface is usually not opened and is only opened when sample injection is required or in other special circumstances. When the vacuum interface is not opened, the chamber of the mass spectrometer is basically completely sealed. Therefore, as long as the vacuum interface is not opened, the vacuum level inside the mass spectrometer can be basically maintained.

[0050] The airtight chamber includes a first chamber 1 and a second chamber 2. An adsorption pump 3 is housed in the second chamber 2. The first chamber 1 and the second chamber 2 are connected by a flow-limiting structure 4. The adsorption pump 3 is a pump that operates based on the principle of adsorption. It utilizes methods such as chemical adsorption, low-temperature adsorption, and post-ionization adsorption to create a vacuum environment. Because the adsorption capacity is limited, it cannot continue to adsorb gas after reaching adsorption equilibrium. Therefore, it is not suitable for operation under high pressure conditions, otherwise, its service life will be significantly reduced. Furthermore, the adsorption pump 3 generally needs to be activated before its first operation. Activation of the adsorption pump 3 requires lowering the pressure in the second chamber 2 (usually within the range of ≤1 Pa) to below the activation pressure, and activation is performed through heating, electricity, or other methods. After activation, the adsorption pump 3 can operate stably. In addition, to ensure the adsorption pump 3 can continue to operate stably, the pressure in the second chamber 2 should also be able to be stably maintained at the operating pressure of the adsorption pump 3, which is typically less than 10 Pa. - 2 Pa. In this embodiment, the adsorption pump 3 can be one or a combination of multiple types of suction pumps, ion pumps, and cryogenic pumps.

[0051] Regarding the first chamber 1, it is typically used to house functional components of a mass spectrometer, such as ion generation, introduction, control, storage, or analysis components, including ion sources, ion optical devices, mass analyzers, and detectors. As one or more of these components, it usually needs to operate in a suitable atmospheric pressure environment. Optionally, the atmospheric pressure range of the first chamber 1 can be set to P1 ≥ 10. -2 Pa allows the ion trap 5 and other functional components to operate in a preferred atmospheric pressure environment, efficiently completing tasks such as ion manipulation, storage, and mass analysis. In this embodiment, the ion trap 5 is preferably used to perform the above tasks. The size of the ion trap 5 is smaller than that of other ion optical devices and mass analyzers, which can well meet the size requirements of miniaturized mass spectrometers.

[0052] It should be noted that the ion source, ion optical device, mass analyzer, and detector can all be housed in the first chamber 1, or partially housed in the first chamber 1, with the remaining portion housed in the second chamber 2, other chambers, or the external environment. Such variations do not exceed the scope of this invention and are all within the protection scope of this invention. Preferably, the detector, mass analyzer, and / or ion source are centrally located in the first chamber 1. By centrally locating the detector, mass analyzer, and / or ion source in the first chamber 1, the first chamber 1 serves as the primary chamber for housing the equipment, while the second chamber 2, supplemented by a flow-limiting structure 4, provides a buffer for the vacuum gas flow. The second chamber 2 can occupy a smaller space while ensuring stable gas pressure in the first chamber 1.

[0053] In this embodiment, an adsorption pump 3 is used to evacuate the first chamber 1 and the second chamber 2. Under the action of the flow-limiting structure 4, the first chamber 1 and the second chamber 2 can provide different gas pressure environments, forming a two-stage differential pumping system. Specifically, the adsorption pump 3 is installed in the second chamber 2, and the flow-limiting structure 4 is set between the first chamber 1 and the second chamber 2. The adsorption pump 3 can be used as the main pump to maintain the vacuum conditions of the mass spectrometer. The working gas pressure of the first chamber 1 can be adjusted by configuring or adjusting the opening size of the flow-limiting structure 4 or the flow rate of the sample injection device (equivalent to the vacuum interface in this embodiment), so that the gas pressure of the first chamber 1 is within the gas pressure range suitable for the operation of its internal components.

[0054] On the other hand, since the first chamber 1 and the second chamber 2 are airtight relative to the external environment, as long as the chambers are pumped to below the activation pressure of the adsorption pump 3 before leaving the factory and the adsorption pump 3 is activated, the activated adsorption pump 3 can meet the load requirements for vacuuming the airtight chambers, without the need to configure a turbo pump or any other type of large-volume pre-pump for the vacuum system, which is conducive to the miniaturization and weight reduction of the vacuum system.

[0055] In this embodiment of the invention, the flow-limiting structure 4 includes, but is not limited to, one or more of the following: a flow-limiting orifice, a flow-limiting valve, or a flow-limiting tube. The orifice diameter, tube diameter, etc., of the flow-limiting structure 4 can be comprehensively determined based on factors such as the gas pressure requirements of the first chamber 1, the throughput of the sample introduction device, and the pumping speed of the adsorption pump 3. The presence of the flow-limiting structure 4 can not only regulate the gas pressure of the first chamber 1, but also stabilize the gas pressure environment within the first chamber 1 by limiting the airflow during vacuuming, thereby enabling the functional components within the first chamber 1 to operate in a stable gas pressure environment.

[0056] In summary, because the mass spectrometer in this embodiment uses adsorption pump 3 as the main pump, and the adsorption pump 3 performs vacuuming based on the adsorption principle after activation, its energy consumption is almost negligible. Moreover, the adsorption pump 3 is small in size, making it particularly suitable for use as a vacuum system in portable mass spectrometers that do not require an external power supply, thus making portable or even handheld mass spectrometers possible. Furthermore, both the first chamber 1 and the second chamber 2 are airtight chambers, which can maintain the gas pressure conditions within the chambers for a long time. The long-term maintained vacuum environment can prevent the adsorption pump 3 from reaching adsorption saturation too quickly, which is beneficial to extending the service life of the adsorption pump 3.

[0057] In other embodiments of the present invention, the adsorption pump 3 can be an ion pump, and the mass spectrometer's mass analyzer can be a sector magnetic deflection mass analyzer, with the sector magnetic deflection mass analyzer and the ion pump sharing a common magnet. Sharing a magnet between the sector magnetic deflection mass analyzer and the ion pump effectively simplifies the apparatus and reduces its size. In this embodiment, the adsorption pump is a separate ion pump, meaning the mass spectrometer does not include other types of adsorption pumps, thus effectively simplifying the apparatus while meeting testing requirements.

[0058] The ion source can be, for example, electrospray, corona discharge, dielectric barrier discharge, glow discharge, electron bombardment, photoionization, etc.

[0059] Mass analyzers can be, for example, ion traps, quadrupoles, time-of-flight devices, sector magnetic deflectors, ion cyclotron resonances, etc.

[0060] Detectors can be, for example, electron multipliers, Faraday tubes, photomultiplier tubes, microchannel plates, etc.

[0061] In this embodiment, the first chamber 1 is connected to the external environment only through a capillary sample introduction device 61. This device has a valve that can be opened / closed for sample introduction. When the mass spectrometer does not require sample introduction, the valve can be closed to maintain a vacuum environment inside the mass spectrometer and prevent air from entering and reducing the lifespan of the adsorption pump 3. When analytical testing is required, the valve can be opened, and the capillary sample introduction device 61 can be used for sample introduction. In some embodiments, the sample introduction device may also include a thermal desorption component for converting solid or liquid samples into gaseous samples for analysis.

[0062] [Second Implementation Method]

[0063] Figure 2 This is a schematic diagram showing the structure of the mass spectrometer in the second embodiment of the present invention.

[0064] In this embodiment, the main structure of the mass spectrometer includes a first chamber 1, a second chamber 2, an adsorption pump 3, a flow-limiting structure 4, and an ion trap 5. Except that in this embodiment, the adsorption pump 3 is further composed of both a getter pump and an ion pump, all other components and reference numerals are the same as in the first embodiment. Figure 1 The same applies as shown, so I will not repeat it here.

[0065] like Figure 2 As shown, in this embodiment, the adsorption pump 3 installed in the second chamber 2 includes a first adsorption pump 31 and a second adsorption pump 32. The first adsorption pump 31 is an adsorption pump that uses an alloy as the adsorption material, and the second adsorption pump 32 is an ion pump. The adsorption pump is the main pump of the mass spectrometer. The ion pump can be connected to the first chamber 1 or the second chamber 2. In this embodiment, the ion pump is connected to the second chamber 2.

[0066] The getter pump, also known as a getter pump, utilizes chemical adsorption entirely, producing no vapor deposition or electromagnetic pollution. It is typically used in large systems as an auxiliary pump to increase pumping speed and improve vacuum levels. This involves pre-evacuating the vacuum using a turbopump or molecular pump, followed by further evacuation to enhance the vacuum. In this embodiment, the adsorption pump 3, combining the getter pump and ion pump, serves as the main pump of the mass spectrometer. By configuring the entire chamber as an airtight chamber, the airtightness required for the getter pump's operation is maintained. This eliminates the need for a turbopump, molecular pump, or any other large, energy-intensive pre-evacuation pump in the vacuum system, promoting miniaturization and weight reduction of the vacuum system. Preferably, in this embodiment, the getter pump is an alloy-based getter pump. Such pumps offer advantages such as high pumping speed (air > 10 L / s), large getter volume, light weight (down to 16 g), vibration-free operation, room-temperature evacuation after activation without power supply, and reusability, making them suitable for building a miniaturized mass spectrometer vacuum system.

[0067] Ion pumps can help remove inert gases that are difficult for aspiration pumps to adsorb, and they also have a certain pumping speed for air. The combination of the two can effectively adsorb or remove different components of gases in the sample gas or air. In particular, aspiration pumps have a pumping speed several times faster and an adsorption capacity of thousands of times for hydrogen, making them well-suited for tests that use hydrogen as a carrier gas, such as gas chromatography, or tests where the sample gas contains a high concentration of hydrogen.

[0068] [Third Implementation Method]

[0069] Figure 3This is a schematic diagram showing the structure of the mass spectrometer in the third embodiment of the present invention.

[0070] In this embodiment, the main structure of the mass spectrometer includes a first chamber 1, a second chamber 2, an adsorption pump 3, a flow-limiting structure 4, and an ion trap 5. Except that the sample introduction device is a membrane sample introduction device 62 in this embodiment, all other components and reference numerals are the same as in the second embodiment. Figure 2 The same applies as shown, so it will not be repeated here. Using the membrane injection device 62 can effectively balance the maintenance of vacuum in the first chamber 1 and the second chamber 2 with the convenience of sample injection.

[0071] [Fourth Implementation Method]

[0072] Figure 4 This is a schematic diagram showing the structure of the mass spectrometer in the fourth embodiment of the present invention.

[0073] In this embodiment, the main structure of the mass spectrometer includes a first chamber 1, a second chamber 2, an adsorption pump 3, a flow-limiting structure 4, and an ion trap 5. Except for the vacuum interface connecting the chambers of the mass spectrometer to the external environment, which also includes a vacuum pump interface 7, all other components and reference numerals are the same as in the first embodiment. Figure 1 The same applies as shown, so I will not repeat it here.

[0074] In this embodiment, the mass spectrometer also includes a vacuum pump interface 7 connected to the second chamber 2. The second chamber 2 can be connected to an external vacuum pump (not shown in the figure) via the vacuum pump interface 7 to pre-pump the gas pressure of the second chamber 2 to the activation gas pressure range of the adsorption pump 3.

[0075] By using the above method, the second chamber 2 is pre-evacuated by an external vacuum pump, which helps the gas pressure in the second chamber 2 to quickly reach the gas pressure environment required to activate the adsorption pump 3. After activation, the external vacuum pump can be disconnected, and the adsorption pump 3 can be maintained by the built-in power supply, thus ensuring the normal operation of the vacuum system of the mass spectrometer.

[0076] refer to Figure 5 This embodiment also provides a method for forming a vacuum system of a mass spectrometer. The vacuum system includes a first chamber 1 and a second chamber 2 connected by a flow-limiting structure 4. An ion trap 5 is disposed in the first chamber 1, and an adsorption pump 3 is disposed in the second chamber 2. The method for forming the vacuum system includes the following steps:

[0077] S1: Use an external vacuum pump to evacuate the second chamber 2 until the gas pressure in the second chamber 2 drops to the activation pressure range of the adsorption pump 3.

[0078] S2: Activate adsorption pump 3;

[0079] S3: Start the adsorption pump 3 to reduce the gas pressure in the first chamber 1 to the working gas pressure range of the ion trap 5;

[0080] S4: Seal the first chamber 1 and the second chamber 2, disconnect the external vacuum pump, and use the adsorption pump 3 as the main pump of the vacuum system to maintain the vacuum level of the first chamber 1 and the second chamber 2.

[0081] In this way, the vacuum system can be pre-vacuumed and the adsorption pump 3 activated simply by connecting the vacuum pump to the vacuum pump interface 7 before initial use, such as at the factory. The vacuum level can then be maintained by the adsorption pump 3. After leaving the factory, the chamber can be opened using the vacuum pump interface 7 for repair or maintenance, improving the convenience of mass spectrometer production and maintenance.

[0082] It should be noted that although the vacuum system of the mass spectrometer in the above embodiment only includes two stages, the first chamber 1 and the second chamber 2, the above embodiment is only illustrative. In other embodiments of the present invention, a vacuum system with three or more stages can also be used. That is, an additional chamber can be set between the first chamber 1 and the second chamber 2. The placement of devices such as the ion source, ion trap 5, plasma generation device, ion optical device, detector or mass analyzer can be determined as needed.

[0083] In the above embodiments of the present invention, the adsorption pump 3 can be used as the main pump. The adsorption pump 3 has the advantages of high pumping speed (pumping speed for air >10 l / s, and the weight of the gas-absorbing material is only 16 g), large gas absorption capacity, light weight, room temperature gas extraction after activation without the need for power supply, and can be reused repeatedly. Using the adsorption pump 3 as the main pump reduces the size of the mass spectrometer, lowers the power consumption and weight of the mass spectrometer, and makes it easier to achieve portability.

[0084] In the above embodiments of the present invention, preferably, at least one of the adsorption pumps 3 used in the mass spectrometer is a getter pump with an alloy as the getter material, and the gas pressure range of the second chamber 2 is P2≤10. -2 The alloy-material intake pump has the advantages of high pumping speed, large intake volume, light weight, room temperature pumping after activation without the need for power, and can be repeatedly activated and used, making it suitable for the miniaturization of mass spectrometers. The pressure range of the second chamber 2 is P2≤10. -2 Pa is the appropriate air pressure environment for suction pumps that use alloys as suction materials, which helps extend the service life of the suction pump.

[0085] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mass spectrometer, characterized in that, The mass spectrometer has an airtight chamber that is connected to the external environment only through a vacuum interface. The chamber includes a first chamber and a second chamber. An adsorption pump is installed in the second chamber. The first chamber and the second chamber are connected by a flow-limiting structure. An ion trap is installed in the first chamber, and the gas pressure range of the first chamber is P1≥10. -2 Pa, the gas pressure in the second chamber is maintained below the activation gas pressure of the adsorption pump.

2. The mass spectrometer according to claim 1, characterized in that, The first chamber is also equipped with a detector, a mass analyzer and / or an ion source.

3. The mass spectrometer according to claim 1, characterized in that, The adsorption pump is an adsorption pump that uses an alloy as the adsorption material, and the air pressure range of the second chamber is P2≤10. -2 Pa.

4. The mass spectrometer according to claim 1, characterized in that, The vacuum interface includes a vacuum pump interface that communicates with the second chamber. The second chamber is connected to an external vacuum pump via the vacuum pump interface, thereby pre-pumping the gas pressure in the second chamber to the activation gas pressure range of the adsorption pump.

5. The mass spectrometer according to claim 1, characterized in that, The adsorption pump is the main pump of the mass spectrometer.

6. The mass spectrometer according to claim 1, characterized in that, It also includes a sample introduction device for introducing samples into the first chamber.

7. The mass spectrometer according to claim 6, characterized in that, The sample introduction device is a gas chromatograph, a capillary sample introduction device, or a membrane sample introduction device.

8. The mass spectrometer according to claim 7, characterized in that, The carrier gas for the gas chromatograph is hydrogen, helium, or nitrogen.

9. The mass spectrometer according to claim 7, characterized in that, The sample introduction device also includes a thermal desorption component.

10. The mass spectrometer according to claim 1, characterized in that, The mass spectrometer is a compact mass spectrometer.

11. The mass spectrometer according to claim 1, characterized in that, The flow-limiting structure is a flow-limiting orifice, a flow-limiting valve, or a flow-limiting tube.

12. The mass spectrometer according to claim 1, characterized in that, The adsorption pump is one or a combination of multiple types of suction pumps, ion pumps, and cryogenic pumps.

13. The mass spectrometer according to claim 12, characterized in that, The adsorption pump includes a first adsorption pump and a second adsorption pump. The first adsorption pump is an adsorption pump that uses an alloy as the adsorption material, and the second adsorption pump is an ion pump. The adsorption pump is the main pump of the mass spectrometer, and the ion pump is connected to the first chamber or the second chamber.

14. The mass spectrometer according to claim 12, characterized in that, The adsorption pump is an ion pump, and the mass spectrometer has a sector magnetic deflection mass analyzer. The sector magnetic deflection mass analyzer and the ion pump share a common magnet.

15. A method for forming a vacuum system of a mass spectrometer, the vacuum system comprising a first chamber and a second chamber connected by a flow-limiting structure, wherein an ion trap is disposed in the first chamber and an adsorption pump is disposed in the second chamber, the method comprising: Use an external vacuum pump to evacuate the second chamber until the gas pressure in the second chamber drops to the activation pressure range of the adsorption pump. Activate the adsorption pump; Start the adsorption pump to reduce the gas pressure in the first chamber to within the working gas pressure range of the ion trap; The first chamber and the second chamber are sealed, and the external vacuum pump is disconnected. The adsorption pump is used as the main pump of the vacuum system to maintain the vacuum level of the first chamber and the second chamber.

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