Radio frequency enhanced and convergent ion source

Abstract

The application discloses a radio frequency enhanced and convergent ion source for mass spectrometry, comprising a VUV light source, an ion source cavity, an auxiliary gas sampling tube, a push-pull electrode, a lamp electrode, a sample sampling tube, an enhanced reaction zone, an ion convergent zone and an ion extraction electrode. The reagent ion generation method determines the reagent ion species and purity, the molecular ion reaction efficiency and the ion transmission efficiency in the source determine the detection sensitivity of the chemical ionization source. In order to further improve the detection performance of the chemical ionization mass spectrometry, the application designs a radio frequency enhanced and convergent ion source, the reagent ions are generated by the vertical irradiation of the VUV light source, the selection of the reagent ions is facilitated and the influence of photoelectrons can be eliminated; in addition, the radio frequency enhanced reaction zone and the radio frequency ion convergent zone are introduced to improve the molecular ion reaction efficiency and the ion transmission efficiency. The application can effectively improve the detection sensitivity and the universality of the chemical ionization mass spectrometry, and has wide application prospects in the fields of atmospheric environment monitoring, industrial processes, medical diagnosis and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mass spectrometry, and particularly relates to a radio frequency enhanced and convergent ion source for a mass spectrometer. BACKGROUND

[0002] The ionization source is one of the cores of the mass spectrometer, is used for converting neutral samples into ions that can be detected by the mass analyzer, is the first link of mass spectrometry, and is related to the detection sensitivity, analyzable compound types, stability and analysis accuracy of the entire mass spectrometer system. In recent years, the soft ionization mass spectrometry technology has gradually become one of the main technologies for online monitoring and rapid analysis of VOCs in complex samples due to its advantages of simple spectrum, few overlapping peaks and the like. Photoionization is a commonly used soft ionization technology for mass spectrometry, and a commonly used light source thereof is a vacuum ultraviolet light source. The ionization process is that sample molecules lose electrons to generate ionization after absorbing photons to reach or exceed their ionization energy. Under normal circumstances, the energy of the absorbed photons is greater than the ionization energy threshold and less than the dissociation energy threshold, so the product fragments are few, and the molecular ion yield is high. Subsequently, researchers combined the photoionization source with the chemical ionization source to develop photo-induced chemical ionization method, improved the detection range of the photoionization source, and improved the universality of the photoionization source to a certain extent. However, since the chemical ionization works at tens to hundreds of pascals, the collision between the molecular ions is violent, on the one hand, the collision needs to be used to increase the ion molecular reaction efficiency, and on the other hand, a convergent electric field needs to be introduced to improve the ion transmission efficiency.

[0003] Through the search of patents and papers, the searched patents related to the radio frequency enhancement and convergent ion source of mass spectrometer are as follows: 1. On February 1, 2013, the Institute of Chemical Physics of the Chinese Academy of Sciences applied for and disclosed a single-photon-chemical ionization source with enhanced radio frequency electric field. The patent uses photoelectrons obtained by photoelectric effect to ionize reagent gas to obtain a chemical ionization source. The chemical ionization initiated by photoelectrons is enhanced by introducing a radio frequency electric field in the ionization zone, the detection sensitivity is improved, and soft ionization of sample molecules with ionization energy higher than that of ultraviolet photons can be realized, thereby widening the range of analyzable samples. 2. On November 21, 2016, the Institute of Chemical Physics of the Chinese Academy of Sciences applied for and disclosed a radio frequency focusing enhanced vacuum ultraviolet light mass spectrometry ionization source. A radio frequency segmented quadrupole ion source is introduced to improve the ion collision frequency and enhance the convergent performance. 3. On November 20, 2018, the Institute of Chemical Physics of the Chinese Academy of Sciences applied for and disclosed a radio frequency enhanced reaction photo-induced chemical ionization source. An angle radio frequency triode is introduced to improve the ion collision frequency and enhance the convergent performance. 4. On December 4, 2019, the Institute of Chemical Physics of the Chinese Academy of Sciences applied for and disclosed a source-in-membrane sampling radio frequency enhanced chemical ionization source. The technology combines source-in-membrane sampling with a radio frequency field to improve the sensitivity of the instrument. However, these technologies have the problem that the collision reaction radio frequency field and the ion transmission radio frequency field cannot be adjusted separately, and since the light source is placed on the axial direction, the photoelectron effect is easy to cause fragmentation of low-energy compounds. Therefore, it is necessary to redesign the structure of the radio frequency enhanced ion source, reduce the influence of the photoelectron effect, and increase the tunability of the ion molecule reaction zone and the ion efficient transmission zone. SUMMARY

[0004] The present application provides a radio frequency enhancement and convergent ion source for mass spectrometry to further improve the ionization efficiency of the photo-induced chemical ionization source.

[0005] To achieve this purpose, the present application adopts the following technical solutions:

[0006] A radio frequency enhancement and convergent ion source, comprising a VUV light source, an ion source cavity, an auxiliary gas sampling tube, a repelling electrode, a lamp head electrode, a sample sampling tube, an enhanced reaction zone, an ion convergent zone and an ion extraction electrode, characterized in that:

[0007] The right direction is the X direction, and the upward direction is the Y direction.

[0008] The ion source cavity is a hollow closed chamber, and the ion source cavity is sequentially provided with a repulsion electrode, a lamp head electrode, an enhanced reaction zone, an ion convergence zone and an ion extraction electrode from left to right along the X direction; the repulsion electrode, the lamp head electrode and the ion extraction electrode are all flat plate structures with through holes in the middle, and they are all placed in parallel, coaxially and at intervals; the middle through hole of the ion extraction electrode is in communication with the outside of the ion source cavity; the VUV light source is arranged on the upper side of the ion source cavity, the light outlet of the VUV light source is located in the ion source cavity, and the side wall surface of the VUV light source is in sealed connection with the upper side wall surface of the ion source cavity; a cylindrical through hole is arranged on the upper side of the lamp head electrode, and the vacuum ultraviolet light emitted by the VUV light source enters the inside of the lamp head electrode through the cylindrical through hole on the upper side of the lamp head electrode;

[0009] A hollow circular tube-shaped auxiliary gas sampling pipe penetrates the left end wall surface of the ion source cavity into the inside of the ion source cavity from the left side outside of the ion source cavity, the auxiliary gas sampling pipe is coaxial with the middle through hole of the repulsion electrode, and the right side outlet of the auxiliary gas sampling pipe extends into the middle through hole of the repulsion electrode, and the outer side wall surface of the auxiliary gas sampling pipe is sealed with the left end wall surface of the ion source cavity;

[0010] A hollow circular tube-shaped sample sampling pipe penetrates the lower end wall surface of the ion source cavity into the inside of the ion source cavity from the lower side outside of the ion source cavity, the upper side outlet of the sample sampling pipe extends into the space between the lamp head electrode and the enhanced reaction zone, and the outer side wall surface of the sample sampling pipe is sealed with the lower end wall surface of the ion source cavity;

[0011] An enhanced reaction zone is arranged in the ion source cavity, and the enhanced reaction zone is arranged between the lamp head electrode and the ion convergence zone; the enhanced reaction zone is composed of 4 or more even number of transmission electrodes (the number of electrode pieces is even); each transmission electrode is a flat plate structure with a through hole in the middle, and the 4 or more transmission electrodes are placed in parallel, coaxially and at intervals; the transmission electrodes are connected with equal resistance resistors with a resistance value of R, and each transmission electrode is respectively connected with one end of an equal capacitance capacitor with a capacitance value of C; along the X direction, the other ends of the capacitors connected with the odd transmission electrodes are connected in series to form a radio frequency port one, and the other ends of the capacitors connected with the even transmission electrodes are connected in series to form a radio frequency port two, and the radio frequency voltage Vrf with the same amplitude and a phase difference of 180° is applied to the radio frequency port one and the radio frequency port two respectively;

[0012] An ion converging region is provided within the ion source cavity, positioned between the enhanced reaction region and the ion extraction electrode. The ion converging region consists of three or more converging electrodes. Each converging electrode comprises four identical sector-shaped plate electrodes, which are formed by cutting a circular plate electrode or annular electrode with a central through-hole into four equal parts at a 90-degree central angle from the center. The four sector-shaped plate electrodes in each converging electrode are distributed sequentially and spaced along the circumference according to their original positions before cutting, all lying on the same plane and forming a central symmetry. The geometric centers of each converging electrode are coaxial, placed at equal intervals in parallel, and the inner diameter of the four sector-shaped plate electrodes in each converging electrode gradually decreases along the X-direction.

[0013] The four sector-shaped plate electrodes on each converging electrode are arranged correspondingly along the X-axis, and the projections of the corresponding sector-shaped plate electrodes on the YZ plane (the plane perpendicular to the X-axis) coincide. The converging electrode forms four mutually spaced and centrally symmetrical projection areas on the YZ plane. Each sector-shaped plate electrode is connected to one end of a capacitor with a capacitance of C. The combination of a sector-shaped plate electrode and other sector-shaped plate electrodes whose projections on the YZ plane coincide is called an electrode row. There are a total of 4 electrode rows in the ion converging region. The other ends of the capacitors connected to the sector-shaped plate electrodes in each electrode row are connected in series and connected to the radio frequency power supply. Adjacent electrode rows are applied with radio frequency voltage Urf of the same amplitude but 180° phase difference, and opposite electrode rows are applied with the same radio frequency voltage. The sector-shaped plate electrodes in each electrode row are connected with resistors of equal resistance R.

[0014] Furthermore, the auxiliary gas injection tube and the sample injection tube are made of one or more of the following materials: metal or non-metal, such as stainless steel, aluminum alloy, copper, PEEK, PTFE, plexiglass, etc., with an inner diameter of 0.1 to 2 mm and a flow rate of 0.01 to 3 L / min.

[0015] Furthermore, the diameter of the through hole in the middle of the repulsion electrode, lamp holder electrode, and transport electrode in the enhanced reaction zone is 2–50 mm; the diameter of the small hole in the center of the inner circle formed by the inner edges of the four fan-shaped plate electrodes in the ion convergence zone decreases sequentially along the X direction within the range of 0.5–50 mm; and the diameter of the through hole in the middle of the ion extraction electrode is 0.2–5 mm.

[0016] Furthermore, along the X direction, the repulsion electrode, lamp head electrode, the first and last transport electrodes of the enhanced reaction zone, the first and last fan-shaped plate electrodes of the ion convergence zone, and the lead-out electrode are arranged in order of voltage from high to low (e.g., different voltages V1, V2, V3, etc. are applied sequentially) to form an electric field of ion reaction and ion transport with a magnitude of 1 to 100 V / cm. Each voltage can be tuned to achieve the best ion molecular reaction efficiency and transport efficiency.

[0017] Further, the reaction zone and the ion convergence zone are respectively applied with different radio frequency voltages Vrf and Urf, so as to facilitate the adjustment of the two zones; the frequency of Vrf is 0.5-5 MHz, and the amplitude is 10-1000 V; the frequency of Urf is 0.5-5 MHz, and the amplitude is 10-1000 V.

[0018] Further, the ion extraction electrode is connected with a mass analyzer, and the mass analyzer is a time-of-flight mass analyzer, a quadrupole mass analyzer or an ion trap mass analyzer.

[0019] Further, the VUV light source is a gas discharge lamp light source, a laser light source or a synchrotron radiation light source; and the internal gas pressure of the ion source cavity is 1-1000 Pa.

[0020] The application designs a radio frequency enhanced and converged ion source, which generates reagent ions by vertical irradiation of a VUV light source, so as to facilitate the selection of reagent ions and eliminate the influence of photoelectrons; in addition, a radio frequency enhanced reaction zone and a radio frequency ion convergence zone are introduced to improve the molecular ion reaction efficiency and the ion transmission efficiency, and the collision reaction radio frequency field and the ion transmission radio frequency field can be individually tuned by reasonable design. The application can effectively improve the detection sensitivity and universality of chemical ionization mass spectrometry, and has wide application prospects in the fields of atmospheric environment monitoring, industrial processes, medical diagnosis and the like. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings further illustrate the present application, but the content of the drawings is not construed as limiting the present application.

[0022] Figure 1 is a schematic diagram of the overall structure of a radio frequency enhanced and converged ion source according to one embodiment of the application; DETAILED DESCRIPTION

[0023] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] It is to be understood that the terms so far as the wordings not specifically set forth in the following description are taken in their generic sense and not in their super specific sense unless specifically so defined in the following description. It is also to be understood that the terminology used herein for the purpose of clarity only and is not to be limiting as the scope of the exemplary embodiments, as would be obvious to one ordinarily skilled in the art, with the aid of present disclosure, while reading the following detailed description, and the accompanying drawings.

[0026] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless otherwise specifically stated. It is also to be understood that the drawings are not necessarily drawn to scale of the various parts shown in the drawings. Techniques, methods, and apparatus known to those of ordinary skill are not discussed in detail because such techniques, methods, and apparatus are considered to be part of the base art. In all examples shown and discussed herein, any specific value should be interpreted as merely an example, and not as a limitation. Other examples of the exemplary embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the several views, and that such numbers and letters are not to be construed as limiting as to the scope of the disclosure.

[0027] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by orientation words such as "front, back, upper, lower, left, right", "horizontal, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without the opposite indication, these orientation words do not indicate and imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application. The orientation words "inner, outer" refer to the inner and outer relative to the contour of the parts themselves.

[0028] The radio frequency enhanced and convergent ion source of the embodiment comprises a VUV light source 5, an ion source cavity 3, an auxiliary gas inlet tube 2, a repelling electrode 4, a lamp head electrode 6, a sample inlet tube 8, an enhanced reaction zone 10, an ion convergent zone 11, and an ion extraction electrode 16, and is characterized in that:

[0029] The right direction is the X direction, and the upward direction is the Y direction.

[0030] The ion source cavity 3 is a hollow sealed chamber, and the ion source cavity 3 is sequentially provided with a repulsion electrode 4, a lamp head electrode 6, an enhanced reaction zone 10, an ion convergence zone 11 and an ion extraction electrode 16 from left to right along the X direction; the repulsion electrode 4, the lamp head electrode 6 and the ion extraction electrode 16 are all flat structures with through holes in the middle, and they are all placed in parallel, coaxially and at intervals; the middle through hole of the ion extraction electrode 16 is in communication with the outside of the ion source cavity 3; the VUV light source 5 is arranged on the upper side of the ion source cavity 3, the light outlet of the VUV light source 5 is located in the ion source cavity 3, and the side wall surface of the VUV light source 5 is in sealed connection with the upper side wall surface of the ion source cavity 3; the lamp head electrode 6 is provided with a cylindrical through hole on the upper side, and the vacuum ultraviolet light 7 emitted by the VUV light source 5 enters the inside of the lamp head electrode 6 through the cylindrical through hole on the upper side of the lamp head electrode 6;

[0031] A hollow circular tube-shaped auxiliary gas sampling pipe 2 penetrates the left end wall surface of the ion source cavity 3 from the outside of the left side of the ion source cavity 3 into the inside of the ion source cavity 3, the auxiliary gas sampling pipe 2 is coaxial with the middle through hole of the repulsion electrode 4, and the right side outlet of the auxiliary gas sampling pipe 2 extends into the inside of the middle through hole of the repulsion electrode 4, and the outer side wall surface of the auxiliary gas sampling pipe 2 is sealed with the left end wall surface of the ion source cavity 3;

[0032] A hollow circular tube-shaped sample sampling pipe 8 penetrates the lower end wall surface of the ion source cavity 3 from the outside of the lower side of the ion source cavity 3 into the inside of the ion source cavity 3, the upper side outlet of the sample sampling pipe 8 extends into the space between the lamp head electrode 6 and the enhanced reaction zone 10, and the outer side wall surface of the sample sampling pipe 8 is sealed with the lower end wall surface of the ion source cavity 3;

[0033] The enhanced reaction zone 10 is arranged between the lamp head electrode 6 and the ion convergence zone 11 in the ion source cavity 3; the enhanced reaction zone 10 is composed of 4 or more even number of transmission electrodes 12 (the number of poles is even); each transmission electrode 12 is a flat structure with a through hole in the middle, and the 4 or more transmission electrodes 12 are placed in parallel, coaxially and at intervals; the transmission electrodes 12 are connected by equal resistance resistors with a resistance of R, and each transmission electrode 12 is respectively connected to one end of an equal capacitance capacitor with a capacitance of C; along the X direction, the other ends of the capacitors connected by the odd transmission electrodes 12 are connected in series to form a radio frequency port one, and the other ends of the capacitors connected by the even transmission electrodes 12 are connected in series to form a radio frequency port two, and the radio frequency port one and the radio frequency port two are respectively applied with radio frequency voltages Vrf with the same amplitude and a phase difference of 180°;

[0034] The ion source cavity 3 is provided with an ion converging zone 11, which is arranged between the enhanced reaction zone 10 and the ion extraction electrode 16; the ion converging zone 11 is composed of three or more converging electrodes 13; each converging electrode 13 is composed of four identical fan-shaped plate electrodes 15, which are cut into four equal parts from the center at an angle of 90 degrees by a circular plate electrode or a circular ring electrode with a hole in the middle; the four fan-shaped plate electrodes 15 in each converging electrode 13 are distributed in sequence along the circumferential direction according to their positions before cutting, and are located on the same plane in a central symmetry; the geometric centers of the converging electrodes 13 are coaxial and are arranged in parallel at equal intervals, and the inner circle diameter of the four fan-shaped plate electrodes 15 of each converging electrode 13 gradually decreases along the X direction;

[0035] The four fan-shaped plate electrodes 15 on each converging electrode 13 are arranged in correspondence along the X axis direction, and the projections of the corresponding fan-shaped plate electrodes on the YZ plane (a plane perpendicular to the X axis) are partially coincident, and the converging electrode 13 forms four mutually spaced and centrally symmetric projection zones on the YZ plane, and each fan-shaped plate electrode 15 is connected to one end of a constant-value capacitor with a capacitance of C; the combination of the fan-shaped plate electrode 15 and the other fan-shaped plate electrode 15 whose projection on the YZ plane coincides with it is called an electrode column, and the ion converging zone 11 has four electrode columns, and the other end of the capacitor connected to the fan-shaped plate electrode 15 in each electrode column is connected in series and connected to the radio frequency power supply; adjacent electrode columns apply radio frequency voltages Urf with the same amplitude and a phase difference of 180°, and opposite electrode columns apply the same radio frequency voltage; the fan-shaped plate electrodes 15 in each electrode column are connected to resistors with a resistance of R.

[0036] Further, the auxiliary gas inlet tube 2 and the sample inlet tube 8 are one or more of metal or non-metal materials, such as one or more of stainless steel, aluminum alloy, or copper, PEEK, Teflon, organic glass, etc., with an inner diameter of 0.1-2 mm and a flow rate of 0.01-3 L / min.

[0037] Preferably, the auxiliary gas inlet tube 2 and the sample inlet tube 8 are passivated stainless steel with an inner diameter of 0.25 mm and a flow rate of 0.05 L / min.

[0038] Further, the diameter of the central hole of the repelling electrode 4, the lamp head electrode 6, and the transmission electrode 12 of the enhanced reaction zone 10 is 2-50 mm; the diameter of the central hole of the inner circle formed by the inner edges of the four fan-shaped plate electrodes 15 of the ion converging zone 11 gradually decreases in the X direction within the size range of 0.5-50 mm; and the diameter of the central hole of the ion extraction electrode 16 is 0.2-5 mm.

[0039] Preferably, the diameter of the central hole of the repelling electrode 4, the lamp head electrode 6 and the reaction electrode 12 of the enhanced reaction zone 10 is 10 mm; the diameter of the central hole of the inner circle of the four sector plate electrodes 15 of the ion converging zone 11 is in the range of 0.5-10 mm and decreases in the X direction; the diameter of the central hole of the ion extraction electrode 16 is 1 mm.

[0040] Further, in the X direction, the repelling electrode 4, the lamp head electrode 6, the enhanced reaction zone 10, the transmission electrodes 12, the sector plate electrodes 15 of the ion converging zone 11 and the extraction electrode 16 are loaded with different voltages in the order of high to low (e.g. V1, V2, V3, …), forming an ion reaction and transmission electric field with a size of 1-100 V / cm, and each voltage can be tuned to achieve the best ion molecular reaction efficiency and transmission efficiency.

[0041] Preferably, in the X direction, the repelling electrode 4, the lamp head electrode 6, the enhanced reaction zone 10, the transmission electrodes 12, the sector plate electrodes 15 of the ion converging zone 11 and the extraction electrode 16 are loaded with different voltages in the order of high to low (e.g. 40 V, 36 V, 32 V, 30 V, 26 V, 18 V, 10 V).

[0042] Further, the enhanced reaction zone 10 and the ion converging zone 11 are respectively applied with different radio frequency voltages Vrf and Urf, which are convenient for the two regions to be adjusted respectively; the frequency of Vrf is 0.5-5 MHz and the amplitude is 10-1000 V; the frequency of Urf is 0.5-5 MHz and the amplitude is 10-1000 V.

[0043] Preferably, the enhanced reaction zone 10 and the ion converging zone 11 are respectively applied with different radio frequency voltages Vrf and Urf, which are convenient for the two regions to be adjusted respectively. The frequency of Vrf is 2 MHz and the amplitude is 200 V; the frequency of Urf is 2 MHz and the amplitude is 400 V.

[0044] Further, the ion extraction electrode 16 is connected with a mass analyzer, and the mass analyzer is a time-of-flight mass analyzer, a quadrupole mass analyzer or an ion trap mass analyzer.

[0045] Further, the VUV light source 5 is a gas discharge lamp light source, a laser light source or a synchrotron radiation light source; the internal pressure of the ion source cavity 3 is 1-1000 Pa.

[0046] Preferably, the internal pressure of the ion source cavity 3 is 500 Pa.

[0047] In the specific work, the radio frequency enhanced and convergent ion source generates reagent ions by the VUV light source 5 vertically irradiating the reagent gas 1 into the ionization zone, the reagent ions generate radio frequency enhanced ionization in the radio frequency enhanced reaction zone 10 and the sample molecules 9, the molecular ion reaction efficiency is improved, then the radio frequency ion convergent zone 11 is used to improve the ion transmission efficiency, finally the generated ions 14 are introduced out of the ion source under the action of the electric field. The application can effectively improve the detection sensitivity and universality of chemical ionization mass spectrometry, and has wide application prospects in the fields of atmospheric environment monitoring, industrial process, medical diagnosis and the like.

[0048] The technical principles of the application are described above in combination with specific embodiments. These descriptions are only for explaining the principles of the application, and cannot be explained as limiting the protection scope of the application in any way. Based on the explanations herein, other specific embodiments of the application can be conceived by those skilled in the art without creative labor, and these equivalent variations or replacements are all included in the scope defined by the claims of the application.

[0049] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A radio frequency enhanced and converging ion source, comprising a VUV light source (5), an ion source cavity (3), an auxiliary gas injection tube (2), a repulsion electrode (4), a lamp head electrode (6), a sample injection tube (8), an enhanced reaction zone (10), an ion converging zone (11), and an ion extraction electrode (16), characterized in that: The X direction is to the right, and the Y direction is upward. The ion source cavity (3) is a hollow, sealed chamber. Inside the ion source cavity (3), from left to right along the X direction, are arranged a repulsion electrode (4), a lamp holder electrode (6), an enhanced reaction zone (10), an ion convergence zone (11), and an ion extraction electrode (16). The repulsion electrode (4), the lamp holder electrode (6), and the ion extraction electrode (16) are all flat plate structures with through holes in the center. They are parallel, with their central holes coaxial and spaced apart. The ion extraction electrode (16) has a central hole in the center... The through hole is connected to the outside of the ion source cavity (3); the VUV light source (5) is placed on the upper side of the ion source cavity (3), the light outlet of the VUV light source (5) is located inside the ion source cavity (3), and the side wall of the VUV light source (5) is sealed to the upper side wall of the ion source cavity (3); a cylindrical through hole is provided on the upper side of the lamp head electrode (6), and the vacuum ultraviolet light (7) emitted by the VUV light source (5) passes through the cylindrical through hole on the upper side of the lamp head electrode (6) and enters the interior of the lamp head electrode (6); A hollow cylindrical auxiliary gas injection tube (2) passes through the left end wall of the ion source cavity (3) outside the left side and enters the interior of the ion source cavity (3). The auxiliary gas injection tube (2) and the middle through hole of the repulsion electrode (4) are coaxial, and the right outlet of the auxiliary gas injection tube (2) extends into the middle through hole of the repulsion electrode (4). The outer wall of the auxiliary gas injection tube (2) is sealed with the left end wall of the ion source cavity (3). A hollow cylindrical sample injection tube (8) passes through the lower wall of the ion source cavity (3) and enters the interior of the ion source cavity (3) from the outside of the lower side. The upper outlet of the sample injection tube (8) extends between the lamp electrode (6) and the enhanced reaction zone (10). The outer wall of the sample injection tube (8) is sealed with the lower wall of the ion source cavity (3). An enhanced reaction zone (10) is provided in the ion source cavity (3). The enhanced reaction zone (10) is located between the lamp head electrode (6) and the ion convergence zone (11). The enhanced reaction zone (10) is composed of four or more even-numbered transmission electrodes (12). The number of electrodes is even. Each transmission electrode (12) is a flat plate structure with a through hole in the middle. The four or more transmission electrodes (12) are parallel, with the through holes in the middle coaxial and spaced apart. The transmission electrodes (12) are connected to resistors with resistance value R. Each transmission electrode (12) is connected to one end of a capacitor with capacitance value C. Along the X direction, the other ends of the capacitors connected to the odd-numbered transmission electrodes (12) are connected in series to form RF port one, and the other ends of the capacitors connected to the even-numbered transmission electrodes (12) are connected in series to form RF port two. RF voltages Vrf with the same amplitude and a phase difference of 180° are applied to RF port one and RF port two respectively. An ion converging region (11) is provided in the ion source cavity (3). The ion converging region (11) is located between the enhanced reaction region (10) and the ion extraction electrode (16). The ion converging region (11) is composed of three or more converging electrodes (13). Each converging electrode (13) is composed of four identical fan-shaped plate electrodes (15). The fan-shaped plate electrodes (15) are formed by cutting a circular plate electrode or a ring electrode with a through hole in the middle into four equal parts from the center of the circle at a central angle of 90 degrees. The four fan-shaped plate electrodes (15) in each converging electrode (13) are distributed sequentially along the circumferential direction according to their positions before cutting, and are all located on the same plane, forming a central symmetry. The geometric centers of each converging electrode (13) are coaxial, and they are placed at equal intervals in parallel. The inner diameter of the four fan-shaped plate electrodes (15) formed by each converging electrode (13) gradually decreases along the X direction. The four sector-shaped plate electrodes (15) on each converging electrode (13) are arranged in a corresponding manner along the X-axis direction, and the projections of the corresponding sector-shaped plate electrodes on the YZ plane (the plane perpendicular to the X-axis) overlap. The converging electrode (13) forms four mutually spaced and centrally symmetrical projection areas on the YZ plane. Each sector-shaped plate electrode (15) is connected to one end of a capacitor with a capacitance of C. The combination of a sector-shaped plate electrode (15) and other sector-shaped plate electrodes (15) whose projections on the YZ plane overlap is called an electrode row. There are a total of 4 electrode rows in the ion converging region (11). The other end of the capacitor connected to the sector-shaped plate electrode (15) in each electrode row is connected in series and connected to the radio frequency power supply. Adjacent electrode rows are applied with radio frequency voltage Urf of the same amplitude and phase difference of 180°, and opposite electrode rows are applied with the same radio frequency voltage. The sector-shaped plate electrodes (15) in each electrode row are connected with resistors of equal resistance R.

2. The ion source according to claim 1, characterized in that: The auxiliary gas inlet tube (2) and the sample inlet tube (8) are made of one or more of metal or non-metal materials, with an inner diameter of 0.1~2 mm and a flow rate of 0.01~3 L / min.

3. The ion source according to claim 1, characterized in that: The diameter of the through hole in the middle of the repulsion electrode (4), the lamp head electrode (6), and the transport electrode (12) of the enhanced reaction zone (10) is 2~50 mm; the diameter of the small hole in the center of the inner circle formed by the inner edges of the four fan-shaped plate electrodes (15) of the ion convergence zone (11) decreases sequentially along the X direction in the range of 0.5~50 mm; the diameter of the through hole in the middle of the ion extraction electrode (16) is 0.2~5 mm.

4. The ion source according to claim 1, characterized in that: Along the X direction, the repulsion electrode (4), the lamp head electrode (6), the head and tail transport electrodes (12) of the enhanced reaction zone (10), the head and tail fan-shaped plate electrodes (15) of the ion convergence zone (11), and the lead-out electrode (16) form an ion reaction and ion transport electric field with a magnitude of 1~100 V / cm in order of voltage from high to low. Each voltage can be tuned to achieve the best ion molecular reaction efficiency and transport efficiency.

5. The ion source according to claim 1, characterized in that: Different radio frequency voltages Vrf and Urf are applied to the enhanced reaction region (10) and the ion aggregation region (11) respectively, so that the two regions can be adjusted separately; the frequency of Vrf is 0.5~5 MHz and the amplitude is 10~1000 V; the frequency of Urf is 0.5~5 MHz and the amplitude is 10~1000 V.

6. The ion source according to claim 1, characterized in that: The ion extraction electrode (16) is connected to a mass analyzer, which is a time-of-flight mass analyzer, a quadrupole mass analyzer, or an ion trap mass analyzer.

7. The ion source according to claim 1, characterized in that: The VUV light source (5) is a gas discharge lamp light source, a laser light source or a synchrotron radiation light source; the internal gas pressure of the ion source cavity (3) is 1~1000 Pa.

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