Mass spectrometer and method for forming vacuum system thereof

Abstract

To provide a mass spectrometer and a vacuum system formation method thereof.SOLUTION: A mass spectrometer includes an airtight chamber communicating with external environment only via a vacuum interface, and the chamber includes a first chamber and a second chamber, the second chamber is provided with an adsorption pump, and the first chamber and the second chamber communicate with each other through a flow restriction structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This application relates to analytical instruments, and in particular to mass spectrometers and methods of forming vacuum systems therefor. [Background technology]

[0002] Traditional mass spectrometers are often used in specially established analytical centers, and their footprint, volume, and weight are all large. The application of quadrupole rod technology has reduced the size and weight of mass spectrometers, but with the birth of ion trap technology, the design and manufacture of lighter mass spectrometers, and even handheld mass spectrometers, has become one of the main directions of mass spectrometry technology development.

[0003] One of the constraints on the weight reduction of mass spectrometers is the vacuum system. Since the requirements for vacuum conditions for each component of a mass spectrometer are different, it is usually necessary to construct a multi-stage vacuum system. In addition, mass analyzers and detectors generally have high requirements for the degree of vacuum, so a pre-exhaust pump with a large footprint and a diffusion pump that operates continuously must be installed at the same time. Even if a vacuum pump with a relatively small volume such as a molecular pump is used, it is difficult to meet the demand for miniaturization of a desktop mass spectrometer. In addition, there is a high demand for a lightweight vacuum system in portable mass spectrometers.

[0004] Adsorption pumps are collection pumps that operate based on the adsorption principle, and create a vacuum environment by means of chemical adsorption, cryogenic adsorption, adsorption after ionization, etc., and include getter pumps, ion pumps, cryopumps, etc. The volume and weight of the pumps can meet the requirements of portable mass spectrometers, but the adsorption amount of the adsorption pump is limited, and it cannot continue to adsorb gas after adsorption saturation. Therefore, it is not usually used alone as a main pump, but as an auxiliary pump, and a separate preliminary exhaust pump must be installed when it is used. In addition, the introduction of a preliminary exhaust pump leads to an increase in the volume and weight of the vacuum system. Furthermore, the operating pressure and activation pressure of the adsorption pump are incompatible with the operating pressure of the components of the miniaturized mass spectrometer (e.g., ion traps, which often operate in a higher pressure environment than the adsorption pump), and this also becomes an obstacle to the application of the adsorption pump alone as the main pump in the miniaturized mass spectrometer.

[0005] Patent Document 1 discloses a technical solution using a cryopump as the main pump of a portable mass spectrometer, and the instruction manual briefly describes a technical solution for operating a portable mass spectrometer using a getter pump instead of a cryopump. However, in this patent, the cryopump directly evacuates the chamber in which the ion trap is located, and no solution is described for matching the difference between the operating pressure of the adsorption pump and the operating pressure of the ion trap.

[0006] Patent Document 2 discloses a technical solution using an adsorption pump as the main pump of a portable mass spectrometer, in which a getter pump is also used to directly evacuate the chamber in which the mass spectrometer is located. However, for the ion trap, there is a risk that the service life of the getter pump will be shortened or that the operational performance of the ion trap will be affected due to the incompatibility of the working pressures of the two. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US8829425B1 [Patent Document 2] US5426300A Summary of the Invention

[0008] In view of the above-mentioned problems, i.e., to provide a vacuum system applicable to desktop and even portable type mass spectrometers, to satisfy the requirements for low power consumption, miniaturization and vacuum degree of such mass spectrometers, and to more accurately match the vacuum conditions required for each component of the mass spectrometer, a first aspect of the present invention provides a mass spectrometer comprising an airtight chamber communicating with the external environment only through a vacuum interface, the chamber including a first chamber and a second chamber, the second chamber being provided with an adsorption pump, and the first chamber and the second chamber communicating with each other through a flow restriction structure.

[0009] Adsorption pumps are characterized by low energy consumption and small size, but they need to be activated and require a relatively low working pressure range, and the vacuum pressure range that they can evacuate may not be compatible with the working pressure range of some components of the mass spectrometer, for example, components that operate at low vacuum. According to the mass spectrometer according to the first aspect of the present invention, by attaching the adsorption pump to the second chamber and providing a flow rate limiting structure between the first chamber and the second chamber, the working pressure of the first chamber can be adjusted by setting or adjusting the size of the opening of the flow rate limiting structure or the magnitude of the flow rate of the vacuum interface (e.g., injection port) so that the pressure of the first chamber is within the pressure range suitable for the components therein.

[0010] Meanwhile, since the first and second chambers are airtight against the external environment, if the chambers are evacuated to below the activation pressure of the adsorption pump before shipment to activate the adsorption pump, the adsorption pump after activation can meet the load requirement of evacuation of the airtight chambers. Therefore, there is no need to provide a turbo pump or any other type of large-volume pre-evacuation pump in the vacuum system, which is advantageous for making the vacuum system smaller and lighter.

[0011] In a preferred technical solution of the present invention, an ion trap is provided in the first chamber, and the pressure range of the first chamber is 10 -2 Pa or more.

[0012] The vacuum system of the mass spectrometer according to the first aspect of the present invention can realize an operating pressure range suitable for the ion trap, and the ion trap can be operated in an appropriate pressure environment. The ion trap can also efficiently handle, store, and analyze ions. Furthermore, its dimensions can meet the component size requirements of a miniaturized mass spectrometer.

[0013] In a preferred technical solution of the invention, an ion optical device, a detector, a mass analyzer and / or an ion source are provided in the first chamber.

[0014] According to the mass spectrometer of the first aspect of the present invention, by integrating the ion optical device, the detector, the mass analyzer and / or the ion source in the first chamber, i.e. by using the first chamber as a chamber that is a main containing means and using the second chamber as a buffer chamber for the air flow that is used for evacuation by introducing a flow restricting structure, it is possible to reduce the footprint of the second chamber and stabilize the air pressure in the first chamber.

[0015] In a preferred technical solution of the present invention, the air pressure in the second chamber is kept below the activation air pressure of the adsorption pump.

[0016] According to this technical solution, the air pressure in the second chamber is kept below the activation air pressure of the adsorption pump, thereby providing and maintaining the air pressure environment required for activation of the adsorption pump, allowing the adsorption pump to adsorb gas molecules in the second chamber, and the low air pressure environment can delay the process of the adsorption pump reaching adsorption saturation, which is advantageous for extending the service life of the adsorption pump.

[0017] In a preferred technical solution of the present invention, the adsorption pump is a getter pump using an alloy as a getter material, and the pressure range of the second chamber is 10 -2 Pa or less.

[0018] According to this technical proposal, the getter pump made of alloy material has the advantages of high pumping speed, large getter amount, light weight, and no power supply required for room temperature exhaust after activation. It can be used repeatedly and is suitable for miniaturization of mass spectrometers. -2 Pa is a pressure environment suitable for the operation of a getter pump that uses an alloy as a getter material.

[0019] In a preferred technical solution of the present invention, the mass spectrometer further includes a vacuum pump interface communicating with the second chamber, and the second chamber communicates with an external vacuum pump via the vacuum pump interface, thereby pre-evacuating the air pressure of the second chamber to within the activation air pressure range of the adsorption pump.

[0020] According to this technical solution, the second chamber is pre-evacuated by an external vacuum pump, which is advantageous in that the air pressure in the second chamber can be quickly increased to the required air pressure environment. After activation is completed, the external vacuum pump can be shut off and the built-in power supply can ensure the electrical energy required to operate the adsorption pump, which reduces the volume of the mass spectrometer, the power consumption and weight of the mass spectrometer, and facilitates portability.

[0021] In a preferred technical solution of the present invention, the adsorption pump is the main pump of the mass spectrometer.

[0022] According to this technical proposal, by using an adsorption pump as the main pump, it is possible to avoid introducing another large-volume pump, such as a turbo pump, as the main pump, thereby reducing the volume of the mass spectrometer and its weight. In addition, after the adsorption pump is activated, an external power supply becomes almost unnecessary, reducing the power consumption of the mass spectrometer.

[0023] A preferred technical solution of the present invention further comprises an injection device for introducing a gas sample into the first chamber.

[0024] In a preferred technical solution of the present invention, the injection device is a gas chromatograph, a capillary injection device or a membrane inlet device.

[0025] In a preferred technical solution of the present invention, the injection device further comprises a thermal desorption module, which is suitable for converting a solid or liquid sample into a gaseous sample for analysis.

[0026] In a preferred technical solution of the present invention, the mass spectrometer is a compact mass spectrometer.

[0027] In a preferred technical solution of the present invention, the flow restricting structure is a flow restricting hole, a flow restricting valve or a flow restricting tube.

[0028] In a preferred technical solution of the present invention, the adsorption pump is one or a combination of a getter pump, an ion pump, and a cryopump.

[0029] In a preferred technical solution of the present invention, the adsorption pump includes a first adsorption pump and a second adsorption pump, the first adsorption pump is a getter pump using an alloy as a getter material, and the second adsorption pump is an ion pump, the getter pump serves as a main pump of the mass spectrometer, and the ion pump is connected to the first chamber or the second chamber.

[0030] According to this technical proposal, the ion pump contributes to the removal of inert gases that are difficult to adsorb by the getter pump, thereby expanding the analytical range to which the mass spectrometer can be applied and improving the load capacity of the vacuum system.

[0031] In a preferred technical solution of the present invention, the adsorption pump includes an ion pump, and the mass analysis device has a magnetic sector mass analyzer that shares a magnetic body with the ion pump. The magnetic sector mass analyzer and the ion pump share a magnetic body, which can effectively simplify the device and reduce the volume of the device. In this preferred technical solution, no other type of adsorption pump is included, and the adsorption pump can be a separate ion pump, so as to effectively simplify the device while meeting the analytical requirements.

[0032] The present invention relates to a method for forming a vacuum system of a mass spectrometer, the vacuum system including a first chamber and a second chamber that are in communication with each other through a flow restriction structure, an ion trap is provided in the first chamber, and an adsorption pump is provided in the second chamber, the forming method including the steps of: evacuating the second chamber using an external vacuum pump until the pressure in the second chamber is reduced to within an activation pressure range of the adsorption pump; activating the adsorption pump; activating an adsorption pump to reduce the pressure in the first chamber to within the operating pressure range of the ion trap; The present invention further provides a method for forming a vacuum system of a mass spectrometer, the method including the steps of closing the first chamber and the second chamber, shutting off an external vacuum pump, and maintaining the vacuum level in the first chamber and the second chamber by using an adsorption pump as a main pump of the vacuum system. [Brief description of the drawings]

[0033] [Figure 1] 1 is a schematic structural diagram of a mass spectrometer according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a schematic structural diagram of a mass spectrometer according to a second embodiment of the present invention. [Diagram 3]FIG. 11 is a schematic structural diagram of a mass spectrometer according to a third embodiment of the present invention. [Figure 4] FIG. 11 is a schematic structural diagram of a mass spectrometer according to a fourth embodiment of the present invention. [Diagram 5] 13 is a flowchart of a method for forming a vacuum system of a mass spectrometer in a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The technical solutions in the embodiments of the present invention will be described below in a clear and complete manner in accordance with the drawings, but it is clear that the described embodiments are only a part of the embodiments of the present invention, and are not all of the embodiments. Based on the embodiments of the present invention, all other embodiments that a person skilled in the art can obtain without creative labor all belong to the protection scope of the present invention.

[0035] term In the present invention, the term "adsorption pump" refers to a collection pump that operates based on the adsorption principle and creates a vacuum environment by means of chemical adsorption, cryogenic adsorption, adsorption after ionization, etc., and includes getter pumps, ion pumps, cryopumps, etc. In the present invention, a "getter pump" is a chemical adsorption pump made of a getter material with a large surface area. The most commonly used getter is a non-evaporable getter (NEG) sintered with an alloy material such as a zirconium vanadium iron alloy. After activation (heating in a vacuum), it can absorb various active gases such as hydrogen gas, oxygen gas, water, carbon monoxide gas, carbon dioxide gas, and nitrogen gas through three processes: surface adsorption, surface dissociation, and bulk diffusion. In the present invention, a "compact mass spectrometer" is a mass spectrometer whose size, volume, weight, and power consumption are much smaller than those of conventional laboratory mass spectrometers, and which, in terms of volume, belongs to the small desktop or portable type and weighs less than 20 kg. In the present invention, the "activation pressure" is a pressure within a sufficiently low pressure range to safely activate the adsorption pump, typically within a pressure range of ≦1 Pa.

[0036] First embodiment As shown in Fig. 1, this embodiment provides a compact mass spectrometer, which has an airtight chamber that communicates with the outside environment only through a vacuum interface, and the vacuum interface is not normally turned on, but is turned on only when sample injection is required or other special circumstances. When the vacuum interface is turned off, the chamber of the mass spectrometer is basically completely sealed, so that the vacuum degree in the mass spectrometer is basically maintained unless the vacuum interface is turned on.

[0037] The airtight chamber includes a first chamber 1 and a second chamber 2, and an adsorption pump 3 is provided in the second chamber 2. The first chamber 1 and the second chamber 2 are connected to each other by a flow rate restricting structure 4. The adsorption pump 3 belongs to a pump that operates based on the adsorption principle, and creates a vacuum environment by means of chemical adsorption, cryogenic adsorption, adsorption after ionization, etc., and has a limit to the amount of adsorption. Since the adsorption pump 3 cannot continue to adsorb gas after reaching an adsorption balance, its service life may be significantly shortened if it is applied to work under high pressure conditions. In addition, the adsorption pump 3 usually needs to be activated before the first work. To activate the adsorption pump 3, the second chamber 2 in which the adsorption pump 3 is located must be depressurized to an activation pressure (usually within a range of ≦1 Pa) or less, and the adsorption pump 3 must be activated by heating, energization, etc. The activated adsorption pump 3 can operate stably, but in order to continue stable operation of the adsorption pump 3, the air pressure in the second chamber 2 must be stably maintained at the operating pressure of the adsorption pump 3. The operating pressure of the adsorption pump 3 is usually 10 -2 The pressure is less than Pa. In this embodiment, the adsorption pump 3 may be one or a combination of a getter pump, an ion pump, and a cryopump.

[0038] The first chamber 1 is typically used to accommodate functional components of a mass spectrometer, such as an ion source, an ion optical device, a mass analyzer, a detector, etc., for ion generation, introduction, control, accumulation, analysis, etc. One or more of the ion source, ion optical device, mass analyzer, detector, etc., typically need to operate in an appropriate pressure environment. Optionally, the pressure range of the first chamber 1 is set to P1≧10. -2 By setting the atmospheric pressure at 0.2 Pa, functional components such as the ion trap 5 can be operated in a suitable atmospheric pressure environment to efficiently complete operations such as ion handling, storage, and mass analysis. In addition, since the size of the ion trap 5 is smaller than other ion optical devices and mass analyzers and satisfies the dimensional requirements of components for a miniaturized mass analyzer, it is preferable to use the ion trap 5 to perform the above operations in this embodiment.

[0039] The ion source, ion optical device, mass analyzer, and detector may all be provided in the first chamber 1, or some of them may be provided in the first chamber 1 and the other parts may be provided in the second chamber 2, another chamber, or the external environment. Such modifications do not go beyond the gist of the present invention and all fall within the scope of protection of the present invention. It is preferable that the detector, mass analyzer, and / or ion source are provided together in the first chamber 1. By providing the detector, mass analyzer, and / or ion source together in the first chamber, that is, by making the first chamber 1 a chamber that is a main storage means and making the second chamber 2 a buffer chamber for the air flow used for evacuation by introducing the flow rate limiting structure 4, the footprint of the second chamber 2 can be reduced and the air pressure of the first chamber 1 can be stabilized.

[0040] In this embodiment, the first chamber 1 and the second chamber 2 are evacuated by the adsorption pump 3, and the first chamber 1 and the second chamber 2 form different pressure environments by the action of the flow restriction structure 4, thereby realizing two-stage differential pumping. Specifically, by attaching the adsorption pump 3 to the second chamber 2 and providing the flow restriction structure 4 between the first chamber 1 and the second chamber 2, the adsorption pump 3 can be used as a main pump that maintains the vacuum conditions of the mass spectrometer, and the operating pressure of the first chamber 1 can be adjusted by adjusting the size of the opening of the flow restriction structure 4 and the magnitude of the flow rate of the injection device (corresponding to the vacuum interface in this embodiment) so that the pressure of the first chamber 1 falls within a pressure range suitable for the components therein.

[0041] Meanwhile, since the first chamber 1 and the second chamber 2 are airtight against the external environment, if the chambers are evacuated to below the activation pressure of the adsorption pump 3 before shipment to activate the adsorption pump 3, the adsorption pump 3 after activation can meet the load requirement of evacuation of the airtight chamber. Therefore, there is no need to arrange a turbo pump or any other type of large-volume pre-evacuation pump in the vacuum system, which is advantageous for making the vacuum system smaller and lighter.

[0042] In the embodiment of the present invention, the flow rate limiting structure 4 may be, but is not limited to, a flow rate limiting hole, a flow rate limiting valve, or a flow rate limiting tube. The hole diameter, tube diameter, etc. of the flow rate limiting structure 4 are comprehensively determined based on factors such as the air pressure requirement of the first chamber 1, the magnitude of the flux of the injection device, and the exhaust speed of the adsorption pump 3. The installation of the flow rate limiting structure 4 can adjust the magnitude of the air pressure in the first chamber 1, and can stabilize the air pressure environment in the first chamber 1 by restricting the airflow during evacuation, and thus the functional components in the first chamber 1 can be operated in a stable air pressure environment.

[0043] As described above, the mass spectrometer in this embodiment uses the adsorption pump 3 as the main pump, and performs vacuum drawing based on the adsorption principle after the adsorption pump 3 is activated, and its energy consumption is considered to be almost negligible, and the size of the adsorption pump 3 is small, making it particularly suitable as a vacuum system for a portable mass analyzer that does not require an external power source, contributing to the realization of a portable mass spectrometer and, ultimately, a handheld mass spectrometer. Furthermore, the first chamber 1 and the second chamber 2 are both airtight chambers and the pressure conditions within the chambers can be maintained for a long period of time, which prevents the adsorption pump 3 from reaching adsorption saturation prematurely due to the vacuum environment, and is advantageous in extending the service life of the adsorption pump 3.

[0044] In another embodiment of the present invention, the adsorption pump 3 may be an ion pump, and the mass analyzer of the mass spectrometer may be a magnetic sector mass analyzer that shares a magnetic body with the ion pump. The magnetic sector mass analyzer and the ion pump share a magnetic body, which can effectively simplify the device and reduce the volume of the device. In this embodiment, the adsorption pump is a separate ion pump, that is, the mass spectrometer does not include other types of adsorption pumps, so as to effectively simplify the device while meeting the analytical requirements.

[0045] The ion source may be, for example, an electrospray, corona discharge, dielectric barrier discharge, glow discharge, electron impact, photoionization, or other ion source.

[0046] The mass analyzer may be, for example, an ion trap, quadrupole rod, time-of-flight, magnetic sector, ion gyro resonance, etc. mass analyzer.

[0047] The detector may be, for example, an electron multiplier, a Faraday cup, a photomultiplier tube, a microchannel plate, or the like.

[0048] In this embodiment, the first chamber 1 communicates with the outside environment only through the capillary injection device 61, which has a valve that can turn injection on and off. When injection is not required, the valve can be turned off to maintain a vacuum environment inside the mass spectrometer. This prevents air from entering and reducing the service life of the adsorption pump 3. When analysis is required, the valve can be opened and injection can be performed using the capillary injection device 61. In some embodiments, the injection device may have a thermal desorption module that converts a solid or liquid sample into a gaseous sample for analysis.

[0049] Second embodiment FIG. 2 is a schematic structural diagram of a mass spectrometer according to a second embodiment of the present invention.

[0050] In this embodiment, the main components of the mass spectrometer include a first chamber 1, a second chamber 2, an adsorption pump 3, a flow rate limiting structure 4, and an ion trap 5. In this embodiment, the adsorption pump 3 is further composed of two types of adsorption pumps 3, a getter pump and an ion pump, and the other members and symbols are all the same as those shown in Fig. 1 of the first embodiment, and therefore their explanation will be omitted here.

[0051] As shown in FIG. 2 , in this embodiment, the adsorption pump 3 provided in the second chamber 2 includes a first adsorption pump 31 and a second adsorption pump 32. The first adsorption pump 31 is a getter pump that uses an alloy as a getter material, and the second adsorption pump 32 is an ion pump. The getter pump serves as 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.

[0052] Since the getter pump or the getter agent pump generally adopts chemical adsorption, no deposition or electromagnetic contamination occurs, and it is often used as an auxiliary pump in a large system to increase the pumping speed and increase the degree of vacuum. That is, after preliminary evacuation with a turbo pump or a molecular pump, it is common to further evacuate using a getter pump to increase the degree of vacuum. On the other hand, in this embodiment, the adsorption pump 3, which is a combination of a getter pump and an ion pump, is used as the main pump of the mass spectrometer, and the entire chamber is made an airtight chamber to maintain the airtight conditions required for the operation of the getter pump itself, so that there is no need to separately install a turbo pump, a molecular pump, or other pre-evacuation pumps that are large in volume and consume a lot of energy in the vacuum system, which is advantageous for reducing the size and weight of the vacuum system. Preferably, in this embodiment, the getter pump is a getter pump that uses an alloy as a getter material. Such a getter pump has the advantages of a high pumping speed (air > 10 L / s), a large getter amount, light weight (lightweight up to 16 g), no vibration, and no need for a power source for room temperature extraction after activation. It can also be used repeatedly, and is suitable for constructing a vacuum system of a miniaturized mass spectrometer.

[0053] The ion pump contributes to the removal of inert gases that are difficult to adsorb by the getter pump, and has a certain pumping speed even for air. The combination of the two makes it possible to effectively adsorb or remove gases of different components in the sample gas or air, and the getter pump in particular has several times the pumping speed and several thousand times the adsorption capacity for hydrogen gas, making it well suited for gas chromatography using hydrogen gas as the carrier gas, or tests in which the sample gas contains a high concentration of hydrogen.

[0054] Third embodiment FIG. 3 is a schematic structural diagram of a mass spectrometer according to a third embodiment of the present invention.

[0055] In this embodiment, the main components of the mass spectrometer include a first chamber 1, a second chamber 2, an adsorption pump 3, a flow rate limiting structure 4, and an ion trap 5. In this embodiment, except that the injection device is a membrane inlet device 62 (membrane interface), the other members and symbols are all the same as those shown in Fig. 2 of the second embodiment, and their explanations are omitted here. The membrane inlet device 62 can effectively balance the maintenance of the vacuum degree in the first chamber 1 and the second chamber 2 and the convenience of injection.

[0056] Fourth embodiment FIG. 4 is a schematic structural diagram of a mass spectrometer according to the fourth embodiment of the present invention.

[0057] In this embodiment, the main components of the mass spectrometer include a first chamber 1, a second chamber 2, an adsorption pump 3, a flow rate limiting structure 4, and an ion trap 5. In this embodiment, the vacuum interface that connects the chambers of the mass spectrometer to the external environment further includes a vacuum pump interface 7, except that the other members and symbols are all the same as those shown in FIG. 1 of the first embodiment, and therefore their description will be omitted here.

[0058] In this embodiment, the mass spectrometer further includes a vacuum pump interface 7 communicating with the second chamber 2, and the second chamber 2 may be connected to an external vacuum pump (not shown) via the vacuum pump interface 7, thereby allowing the air pressure of the second chamber 2 to be pre-evacuated to within the activation air pressure range of the adsorption pump 3.

[0059] In this way, pre-evacuating the second chamber 2 with an external vacuum pump is advantageous in that the air pressure inside the second chamber 2 can be quickly raised to the air pressure environment required for activating the adsorption pump 3. Furthermore, after activation is complete, the external vacuum pump can be shut off and the electrical energy required to operate the adsorption pump 3 can be guaranteed using only the built-in power supply, so that normal operation of the vacuum system of the mass spectrometer can always be maintained.

[0060] Referring to Fig. 5, this embodiment provides a method for forming a vacuum system of a mass spectrometer, the vacuum system including a first chamber 1 and a second chamber 2 that communicate with each other through a flow restriction structure 4, an ion trap 5 is provided in the first chamber 1, and an adsorption pump 3 is provided in the second chamber 2, the forming method includes: Step S1: evacuating the second chamber 2 using an external vacuum pump until the pressure in the second chamber 2 is reduced to within the activation pressure range of the adsorption pump 3; a step S2 of activating the adsorption pump 3; Step S3: activating the adsorption pump 3 to reduce the pressure in the first chamber 1 to within the working pressure range of the ion trap 5; The method includes a step S4 of closing the first chamber 1 and the second chamber 2, shutting off the external vacuum pump, and maintaining the vacuum level in the first chamber 1 and the second chamber 2 by using the suction pump 3 as the main pump of the vacuum system.

[0061] As described above, the vacuum system can complete preliminary vacuum drawing and activation of the adsorption pump 3 before the first use, for example before shipping from the factory, simply by connecting the vacuum pump to the vacuum pump interface 7, and the subsequent vacuum level is maintained by the adsorption pump 3. After shipping from the factory, the chamber can also be opened through the vacuum pump interface 7 for repairs, improving the convenience of manufacturing and maintenance of the mass spectrometer.

[0062] In the above embodiment, the vacuum system of the mass spectrometer includes a two-stage structure such as the first chamber 1 and the second chamber 2, but the above embodiment is merely illustrative, and a three-stage or more vacuum system may be adopted in other embodiments of the present invention. That is, an additional chamber may be provided between the first chamber 1 and the second chamber 2, and the respective positions of devices such as the ion source, the ion generating device such as the ion trap 5, the ion optical device, the detector, or the mass analyzer are determined as necessary.

[0063] In the above-described embodiment of the present invention, the adsorption pump 3 may be used as the main pump. The adsorption pump 3 has the advantages of a high pumping speed (pumping speed for air > 10 L / s, getter material weight is only 16 g), a large getter amount, light weight, no power supply required for room temperature extraction after activation, and can be used repeatedly. By using the adsorption pump 3 as the main pump, the volume of the mass spectrometer is reduced, and the power consumption and weight are also reduced accordingly, making it easier to achieve portability.

[0064] In the above embodiment of the present invention, at least one of the adsorption pumps 3 used in the mass spectrometer is a getter pump using an alloy as a getter material, and the pressure range of the second chamber 2 is P2≦10 -2 The getter pump, which is made of alloy material, has the advantages of a high suction speed, a large getter amount, light weight, and no power supply required for room temperature extraction after activation. It can be activated and used repeatedly, and is suitable for miniaturization of mass spectrometers. The pressure range of the second chamber is P2≦10 -2 Pa is a pressure environment suitable for the operation of a getter pump using the alloy as a getter material, and is advantageous for extending the service life of the getter pump.

[0065] The above is only the preferred embodiments of the present invention, rather than limiting the present invention, and any modifications, equivalent replacements and improvements made according to the spirit of the present invention shall fall within the protection scope of the present invention. [Explanation of symbols]

[0066] 1 First Chamber 2 Second Chamber 3. Suction pump 4 Flow restriction structure 5. Ion Trap 61 Capillary injection device 62 Membrane Inlet Device 7 Vacuum Pump Interface

Claims

1. A mass spectrometer comprising an airtight chamber, the airtight chamber including a first chamber and a second chamber, an ion trap provided in the first chamber, no adsorption pump provided, an adsorption pump provided in the second chamber, the first chamber and the second chamber communicating with each other through a flow restriction structure, a pressure range of the first chamber being 10 −2 Pa or more, and a detector, a mass analyzer and / or an ion source provided in the first chamber.

2. 2. The mass spectrometer of claim 1, wherein the pressure in the second chamber is equal to or lower than an activation pressure of the adsorption pump.

3. The adsorption pump is a getter pump using an alloy as a getter material, and the pressure range of the second chamber is 10 －２ 3. The mass spectrometer according to claim 2, wherein the pressure is 0.1 Pa or less.

4. 2. The mass spectrometer of claim 1, further comprising a vacuum pump interface communicating with an external vacuum pump that pre-evacuates the second chamber to within an activation pressure range of the adsorption pump.

5. 2. The mass spectrometer according to claim 1, wherein the adsorption pump is a main pump of the mass spectrometer.

6. 2. The mass spectrometer of claim 1, further comprising an injection device for introducing a sample into the first chamber.

7. 7. The mass spectrometer of claim 6, wherein the injector is a gas chromatograph, a capillary sampling device, or a membrane inlet device.

8. 8. The mass spectrometer according to claim 7, wherein the carrier gas of the gas chromatograph is hydrogen gas, helium gas or nitrogen gas.

9. The mass spectrometer of claim 7 , wherein the injection device further comprises a thermal desorption module.

10. 2. The mass spectrometer according to claim 1, wherein the mass spectrometer is a compact mass spectrometer.

11. 2. The mass spectrometer according to claim 1, wherein the flow rate restricting structure is a flow rate restricting hole, a flow rate restricting valve or a flow rate restricting tube.

12. 2. The mass spectrometer according to claim 1, wherein the adsorption pump is one or a combination of a getter pump, an ion pump, and a cryopump.

13. 13. The mass spectrometer according to claim 12, wherein the adsorption pump includes a first adsorption pump and a second adsorption pump, the first adsorption pump being a getter pump using an alloy as a getter material, the second adsorption pump being an ion pump, and the getter pump being a main pump of the mass spectrometer.

14. 13. The mass spectrometer of claim 12, wherein the adsorption pump is an ion pump and the mass spectrometer comprises a magnetic sector mass analyzer.

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