A vacuum ultraviolet lamp structure and preparation method thereof, and photoionization sensor

Abstract

The present invention relates to the field of photoionization gas detection technology, and in particular to a vacuum ultraviolet lamp structure and a preparation method thereof, and a photoionization sensor. A vacuum ultraviolet window is provided at an opening at one end of a glass shell of the vacuum ultraviolet lamp, and a closed chamber is formed inside the glass shell of the vacuum ultraviolet lamp, and the chamber is filled with a working gas; a first contact piece, a second contact piece, and a collecting electrode structure are fixedly provided on the surface of the vacuum ultraviolet window, and the collecting electrode structure includes at least two groups of mutually insulated electrode structures, and the first contact piece and the second contact piece are electrically connected to the two groups of electrode structures respectively. The beneficial effect of the present invention is that the present invention combines the ionization chamber, the collecting electrode structure, and the glass shell of the vacuum ultraviolet lamp into a whole, realizes the in-situ ionization and collection of chemical gases, greatly simplifies the photoionization and ion collection structure of the photoionization sensor, and reduces the number and complexity of the parts structure of the ionization chamber.

Description

Technical Field

[0001] The invention relates to the technical field of photoionization gas detection, and in particular to a vacuum ultraviolet lamp structure and a preparation method thereof, and a photoionization sensor. Background Art

[0002] Photoionization detector (PID) is a sensor used to detect a variety of chemical gases. Its core principle is that the detected gas absorbs photons higher than the ionization energy of the gas molecules in the ionization zone inside the PID sensor, and is ionized into positive ions and electrons. The positive ions and electrons migrate to the collecting electrode under the action of the external electric field to form a weak ion current, which can be further amplified and output as a voltage signal. Within a certain concentration range, the gas concentration is positively correlated with the ion current, so the gas can be detected by the amplified voltage value.

[0003] This gas detection method has the advantages of quasi-real-time response, non-destructive testing, and a wide range of detectable gases. It became a common gas chromatography post-stage detector in the 1980s and 1990s. In recent years, RAE Corporation of the United States has applied this principle to independent detection equipment for online or on-site inspections and personnel safety protection, achieving relatively ideal detection results. Furthermore, the Baseline series of micro sensors of Ion Science and Ametek Mocon have further reduced the size and weight, and developed the micro PID sensor into a plug-in sensor compatible with a variety of devices.

[0004] A typical PID device includes a power input module, a vacuum ultraviolet lamp, an excitation circuit, an ion collection electrode, and a signal amplification module. The main process is divided into the ultraviolet light generation process and the ion collection detection process. The ionization energy of common organic gas molecules is generally concentrated between 8-11eV, so it is necessary to select vacuum ultraviolet light with a photon energy exceeding 10eV to ionize the detected gas. The emission spectrum of Kr atoms has two bright lines at 10.0eV and 10.6eV (corresponding to 123.6nm and 118.0nm, respectively). This energy cannot ionize water, oxygen, nitrogen, carbon dioxide and other molecules in the air, but it can effectively ionize most organic matter and some inorganic matter, so it is suitable as a UV light source. In addition, by inducing the plasma transition of the packaged Kr gas with high-frequency alternating current, ultraviolet light output can be achieved without the need for additional pins, so this method is suitable for miniaturization of equipment.

[0005] Although micro PID sensors are widely used at present, due to their small internal space and complex structure, the penetration distance of vacuum ultraviolet light in the air is only a few millimeters, and the diameter is only a few millimeters. The molecules to be measured need to be fully ionized within this space, migrate under the action of the electric field, and be collected by the ion collecting electrode. At the same time, the ion current is only at the picoampere level. Therefore, the ion collecting electrode itself is required to have extremely low leakage current to improve the reliability of the response to low-concentration gases.

[0006] At present, the more commonly used design method is to process tiny electrode sheets as collecting electrodes, which are fixed with non-conductive structural parts before collection. A voltage difference is built in the horizontal or vertical direction of the ultraviolet light emission in space to ionize gas molecules and directly collect charged particles under the action of the electric field. This design requires the use of multiple tiny structures as electrodes, and each electrode needs to be connected to an external pin, which makes the structure manufacturing and assembly more complicated. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a vacuum ultraviolet lamp structure and a preparation method, and a photoionization sensor, which greatly simplifies the vacuum ultraviolet lamp structure and meets the design requirements of the ionization cavity and the collecting electrode of the micro photoionization sensor.

[0008] The technical solution of the present invention for solving the above technical problems is as follows: a vacuum ultraviolet lamp structure, comprising a vacuum ultraviolet lamp glass shell, an opening is provided on one end of the vacuum ultraviolet lamp glass shell, a vacuum ultraviolet window for sealing the opening is provided at the opening, the vacuum ultraviolet window is sealedly connected to the vacuum ultraviolet lamp glass shell so that a closed chamber is formed inside the vacuum ultraviolet lamp glass shell, and the chamber is filled with working gas; a first contact piece, a second contact piece and a collecting electrode structure are fixedly provided on the surface of the vacuum ultraviolet window, and the collecting electrode structure comprises at least two groups of mutually insulated electrode structures, the first contact piece and the second contact piece are insulated from each other, and the first contact piece and the second contact piece are electrically connected to the two groups of electrode structures respectively.

[0009] The beneficial effects of the present invention are as follows: the present invention directly arranges the ionization chamber and the collecting electrode structure on the vacuum ultraviolet window, combines the ionization chamber, the collecting electrode structure, and the glass shell of the vacuum ultraviolet lamp into a whole, realizes the in-situ ionization and collection of chemical gases, greatly simplifies the photoionization and ion collection structure of the photoionization sensor, greatly simplifies the design and assembly of the ionization chamber and the collecting electrode structure, and effectively reduces the number and complexity of the parts structure of the ionization chamber.

[0010] Based on the above technical solution, the present invention can also be improved as follows.

[0011] Furthermore, the collecting electrode structure includes a first electrode structure and a second electrode structure, the first electrode structure and the second electrode structure are arranged between the first contact piece and the second contact piece, the first electrode structure and the first contact piece are electrically connected, and the second electrode structure and the second contact piece are electrically connected.

[0012] Further, the first electrode structure includes a plurality of first electrode strips arranged in parallel to each other, and the second electrode structure includes a plurality of second electrode strips arranged in parallel to each other, one end of the plurality of first electrode strips is electrically connected to the first contact member, one end of the plurality of second electrode strips is electrically connected to the second contact member, the plurality of first electrode strips and the plurality of second electrode strips are arranged in parallel and interdigitated manner, and adjacent first electrode strips and second electrode strips are arranged at intervals.

[0013] The beneficial effect of adopting the above further scheme is: by setting multiple first electrode strips and multiple second electrode strips, the more the number of first electrode strips and second electrode strips and the longer the length, the longer the charge collection area and thus the higher the sensitivity. Therefore, the sensitivity can be adjusted by changing the number and length of the first electrode strips and the second electrode strips.

[0014] Furthermore, the first electrode structure includes an arc-shaped first electrode arc, and the second electrode structure includes an arc-shaped second electrode arc and an electrode ring, the electrode ring, the first electrode arc and the second electrode arc are concentrically arranged from inside to outside, the first electrode arc is electrically connected to the first contact piece, and the electrode ring and the second electrode arc are electrically connected to the second contact piece.

[0015] The beneficial effect of adopting the above further scheme is: the longer the length of the first electrode arc and the second electrode arc, the longer the circumference of the electrode ring, the longer the charge collection area, and thus the higher the sensitivity. Therefore, the sensitivity can be adjusted by changing the length of the first electrode arc and the second electrode arc and the circumference of the electrode ring.

[0016] Furthermore, the vacuum ultraviolet window is made of MgF2 or CaF2 or LiF.

[0017] Furthermore, the collecting electrode structure, the first contact member and the second contact member are metal thin film structures fixed on the vacuum ultraviolet window by chemical plating or thermal evaporation.

[0018] The beneficial effect of adopting the above further scheme is: a metal film structure is plated on the vacuum ultraviolet window by chemical electroplating or thermal evaporation, which is not only convenient for manufacturing but also can ensure the stability of the fixed collecting electrode structure.

[0019] The present invention also provides the following technical solution to solve the above technical problem: the method for preparing the above vacuum ultraviolet lamp structure comprises the following steps:

[0020] Step 1: forming a first contact member, a second contact member and a collecting electrode structure on one side surface of the vacuum ultraviolet window by chemical plating or thermal evaporation;

[0021] Step 2, bonding the vacuum ultraviolet window after step 1 to one end of a glass tube used as a glass shell of a vacuum ultraviolet lamp, so that the two are sealed and fixed;

[0022] Step three, connect the other end of the glass tube to the vacuum pump, extract the air in the inner cavity of the glass tube and pump in the working gas, then use a high-temperature flame to soften the end of the glass tube away from the vacuum ultraviolet window and seal it to make a vacuum ultraviolet lamp structure with an ion collecting electrode.

[0023] The beneficial effect of the above technical solution is that this method constructs the electrode directly on the vacuum ultraviolet window, which can greatly simplify the design, structure, assembly and other processes of the ionization chamber and the ion collection electrode, and help to further optimize the weight, volume, ease of use and durability of the equipment.

[0024] Furthermore, the method of making the first contact piece, the second contact piece and the collecting electrode structure on the side surface of the vacuum ultraviolet window by chemical electroplating or thermal evaporation in step one includes: forming a metal film by chemical electroplating or thermal evaporation; and then making the metal film into the first contact piece, the second contact piece and the collecting electrode structure by an etching process.

[0025] The beneficial effect of adopting the above further scheme is: a metal film structure is plated on the vacuum ultraviolet window by chemical electroplating or thermal evaporation, which is not only convenient for manufacturing but also can ensure the stability of the fixed collecting electrode structure.

[0026] Furthermore, the method of making a first contact, a second contact and a collecting electrode structure on one side surface of the vacuum ultraviolet window by thermal evaporation in step one includes: directly using a mask in the shape of the first contact, the second contact and the collecting electrode structure to cover one side surface of the vacuum ultraviolet window; and then evaporating a gold plating solution onto the vacuum ultraviolet window.

[0027] The beneficial effect of adopting the above further solution is that the first contact piece, the second contact piece and the collecting electrode structure are manufactured by the method of evaporation after mask covering, and the corresponding structures of the required shapes can be directly manufactured without the need for additional etching.

[0028] The present invention also provides the following technical solutions to solve the above-mentioned technical problems: a photoionization sensor, comprising the above-mentioned vacuum ultraviolet lamp structure and a bias circuit, an amplifying circuit, an excitation circuit, a voltage output circuit and a power module, wherein the output end of the bias circuit is electrically connected to the first contact piece, the output end of the amplifying circuit is electrically connected to the second contact piece, the output end of the voltage output circuit is electrically connected to the input end of the amplifying circuit, the output end of the excitation circuit is electrically connected to the excitation coil arranged on the outside of the glass shell of the vacuum ultraviolet lamp, and the output end of the power module is electrically connected to the input end of the amplifying circuit and the input end of the excitation circuit respectively.

[0029] The beneficial effect of adopting the above scheme is that the present invention combines the ionization chamber, the collecting electrode structure, and the vacuum ultraviolet lamp glass shell into a whole, which greatly simplifies the structure of the photoionization sensor, is easy to manufacture, and can optimize the weight, volume, ease of use and durability of the photoionization sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of the vacuum ultraviolet lamp structure of the present invention;

[0031] Figure 2 A schematic diagram of a collecting electrode structure provided in a vacuum ultraviolet window in a first embodiment of the present invention;

[0032] Figure 3 A schematic diagram of a collecting electrode structure provided in a vacuum ultraviolet window in a second embodiment of the present invention;

[0033] Figure 4 It is a schematic diagram of the structure of the photoionization sensor in the present invention;

[0034] Figure 5 A circuit diagram of an excitation circuit in a photoionization sensor of the present invention;

[0035] Figure 6 is a circuit diagram of an amplifier circuit in a photoionization sensor in the present invention;

[0036] Figure 7 A comparison diagram of concentration-response curves of first electrode strips of two different lengths used in the present invention;

[0037] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0038] 1. Vacuum ultraviolet lamp glass shell; 2. Vacuum ultraviolet window; 3. Chamber; 4. First contact piece; 5. Second contact piece; 6. Collecting electrode structure; 61. First electrode strip; 62. First electrode arc; 71. Second electrode strip; 72. Second electrode arc; 73. Electrode ring; 8. Bias circuit; 9. Amplification circuit; 10. Excitation circuit; 11. Voltage output circuit; 12. Power supply module; 13. Excitation coil. DETAILED DESCRIPTION

[0039] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0040] like Figure 1 As shown, an embodiment of a vacuum ultraviolet lamp structure in the present invention includes a vacuum ultraviolet lamp glass shell 1, an opening is provided on one end of the vacuum ultraviolet lamp glass shell 1, and a vacuum ultraviolet window 2 for sealing the opening is provided at the opening, and the vacuum ultraviolet window 2 is made of MgF2 or CaF2 or LiF, and the vacuum ultraviolet window 2 is sealedly connected to the vacuum ultraviolet lamp glass shell 1 so that a closed chamber 3 is formed inside the vacuum ultraviolet lamp glass shell 1, and the chamber 3 is filled with a working gas, and the working gas can be selected from Kr, Ar, etc., and the chamber 3 is filled with a working gas. The pressure is 10-5000Pa; the vacuum ultraviolet window 2 is fixed at the opening of the vacuum ultraviolet lamp glass shell 1 by a low-temperature molten glass material; a first contact piece 4, a second contact piece 5 and a collecting electrode structure 6 are fixed on the surface of the vacuum ultraviolet window 2, and the collecting electrode structure 6 includes at least two groups of mutually insulated electrode structures, the first contact piece 4 and the second contact piece 5 are insulated from each other, the first contact piece 4 and the second contact piece 5 are electrically connected to the two groups of electrode structures respectively, and the outside of the vacuum ultraviolet window 2 and the collecting electrode structure 6 is an open ionization zone.

[0041] like Figure 2As shown, in a first embodiment of a vacuum ultraviolet lamp structure of the present invention, the collecting electrode structure 6 includes a first electrode structure and a second electrode structure, the first electrode structure and the second electrode structure are arranged between the first contact member 4 and the second contact member 5, the first electrode structure is electrically connected to the first contact member 4, and the second electrode structure is electrically connected to the second contact member 5. Specifically, the first electrode structure includes a plurality of first electrode strips 61 arranged in parallel with each other, and the second electrode structure includes a plurality of second electrode strips 71 arranged in parallel with each other, one end of the plurality of first electrode strips 61 is electrically connected to the first contact member 4, and one end of the plurality of second electrode strips 71 is electrically connected to the second contact member 5, the plurality of first electrode strips 61 and the plurality of second electrode strips 71 are arranged in parallel and interdigitated, and the adjacent first electrode strips 61 and the second electrode strips 71 are arranged at intervals. By arranging a plurality of first electrode strips 61 and a plurality of second electrode strips 71, the more the number of first electrode strips 61 and the second electrode strips 71, the longer the length, the longer the charge collection area, and thus the higher the sensitivity. Therefore, the sensitivity can be adjusted by changing the number and length of the first electrode strips 61 and the second electrode strips 71.

[0042] like Figure 3 As shown, in a second embodiment of a vacuum ultraviolet lamp structure of the present invention, the collecting electrode structure 6 includes a first electrode structure and a second electrode structure, the first electrode structure and the second electrode structure are arranged between the first contact member 4 and the second contact member 5, the first electrode structure is electrically connected to the first contact member 4, and the second electrode structure is electrically connected to the second contact member 5. Specifically, the first electrode structure includes an arc-shaped first electrode arc 62, the second electrode structure includes an arc-shaped second electrode arc 72 and an electrode ring 73, the electrode ring 73, the first electrode arc 62 and the second electrode arc 72 are concentrically arranged from inside to outside, the first electrode arc 62 is electrically connected to the first contact member 4, the electrode ring 73 and the second electrode arc 72 are electrically connected to the second contact member 5, the longer the length of the first electrode arc 62 and the second electrode arc 72, the longer the circumference of the electrode ring 73, the longer the charge collection area is, and thus the sensitivity is higher. Therefore, the sensitivity can be adjusted by changing the length of the first electrode arc 62 and the second electrode arc 72 and the circumference of the electrode ring 73.

[0043] A method for preparing a vacuum ultraviolet lamp structure in the present invention comprises the following steps:

[0044] Step 1: a first contact member 4, a second contact member 5 and a collecting electrode structure 6 are formed on one side surface of the vacuum ultraviolet window 2 by chemical plating or thermal evaporation;

[0045] Step 2, bonding the vacuum ultraviolet window 2 after step 1 to one end of the glass tube used as the glass shell 1 of the vacuum ultraviolet lamp, so that the two are sealed and fixed;

[0046] Step three, connect the other end of the glass tube to the vacuum pump, extract the air in the inner cavity of the glass tube and pump in the working gas, then use a high-temperature flame to soften the end of the glass tube away from the vacuum ultraviolet window 2 and seal it to make a vacuum ultraviolet lamp structure with an ion collecting electrode.

[0047] In one embodiment of the above method of the present invention, the method of manufacturing the first contact member 4, the second contact member 5 and the collecting electrode structure 6 on one side surface of the vacuum ultraviolet window 2 by chemical plating or thermal evaporation in step 1 includes: forming a metal film by chemical plating or thermal evaporation; and then manufacturing the metal film into the first contact member 4, the second contact member 5 and the collecting electrode structure 6 by etching. Plating a metal film structure on the vacuum ultraviolet window 2 by chemical plating or thermal evaporation is not only convenient for manufacturing, but also can ensure the stability of the fixing of the collecting electrode structure 6.

[0048] In another embodiment of the above method of the present invention, the method of manufacturing the first contact 4, the second contact 5 and the collecting electrode structure 6 on one side surface of the vacuum ultraviolet window 2 by thermal evaporation in the step 1 includes: directly using a mask in the shape of the first contact 4, the second contact 5 and the collecting electrode structure 6 to cover one side surface of the vacuum ultraviolet window 2; and then evaporating a gold plating solution onto the vacuum ultraviolet window 2. The first contact 4, the second contact 5 and the collecting electrode structure 6 are manufactured by the method of evaporation after mask covering, and the corresponding structures of the required shapes can be directly manufactured without the need for additional etching.

[0049] The method in this embodiment constructs the electrode directly on the vacuum ultraviolet window 2, which can greatly simplify the design, structure, assembly and other processes of the ionization chamber and the ion collection electrode, and help to further optimize the weight, volume, ease of use and durability of the equipment.

[0050] like Figure 4As shown, a photoionization sensor in the present invention includes the above-mentioned vacuum ultraviolet lamp structure and bias circuit 8, amplifier circuit 9, excitation circuit 10, voltage output circuit 11 and power module 12, the output end of the bias circuit 8 is electrically connected to the first contact member 4, the output end of the amplifier circuit 9 is electrically connected to the second contact member 5, the output end of the voltage output circuit 11 is electrically connected to the input end of the amplifier circuit 9, the output end of the excitation circuit 10 is electrically connected to the excitation coil 13 arranged outside the vacuum ultraviolet lamp glass shell 1, and the output end of the power module 12 is electrically connected to the input end of the amplifier circuit 9 and the input end of the excitation circuit 10 respectively. Combining the ionization cavity, the collecting electrode structure 6 and the vacuum ultraviolet lamp glass shell 1 into a whole greatly simplifies the structure of the photoionization sensor, is easy to manufacture, and can optimize the weight, volume, ease of use and durability of the photoionization sensor.

[0051] like Figure 5 As shown, the excitation circuit 10 adopts the circuit architecture of Royer, also known as a push-pull self-excited oscillation circuit, which drives the excitation coil 13 through a switching transistor, and uses the feedback winding to control the switch tube to alternately conduct to achieve self-excited oscillation, so that an alternating current is generated on the primary side, and the required AC voltage is generated on the secondary side according to the transformer turns ratio. Figure 6 As shown, the amplifier circuit 9 uses a transimpedance amplifier to convert the charge collected on the ion collecting electrode into the output voltage of the operational amplifier. Figure 6 Point A is connected to the second contact 5, and the charges collected on the electrode generate a current of pA level, which flows through the gain resistor Rf of GΩ level, and generates a voltage at the output point B of the operational amplifier, which can represent the amount of charges ionized by the ultraviolet lamp.

[0052] The following tests were conducted on a photoionization sensor with two first electrode strips 61 of different lengths: (1) Long first electrode strip 61 group, the material of the vacuum ultraviolet window 2 was MgF2, the working gas was Kr, the window material diameter was 8 mm, the outer diameter of the vacuum ultraviolet lamp glass shell 1 was 6 mm, the inner diameter was 5 mm, the ultraviolet window was circular and concentric with the cylinder of the vacuum ultraviolet lamp glass shell 1. The metal film was Au, and a mask evaporation process was used. The metal layer width of the first contact member 4 and the second contact member 5 was 1 mm, and the width of the first electrode strip 61 and the second electrode strip 71 was 0.1 mm. Specifically, Figure 2 As shown, each electrode stripe is 1 / 3 of the radius apart, one end of the first electrode strip 61 contacts the first contact member 4, and the total length is about 2 / 3 of the length of the intersection of the straight line and the circle. Therefore, the lengths of the three electrode lines on the left are 4mm, 5.3mm, and 4mm, and the lengths of the two electrode lines on the right are 5mm and 5mm, and the second electrode line on the left passes through the center of the circle.

[0053] (2) A group of short first electrode strips 61 , based on the size of (1), the length of the first electrode strips 61 is reduced to 1 / 3 of the original length.

[0054] A vacuum ultraviolet lamp with a high frequency and high voltage of 1100V and 125kHz and a working gas of Kr gas was used to make it work normally and test its sensitivity. The detection gas is isobutylene (IBE), which has an ionization energy of 9.43eV and can be effectively ionized by the Kr ultraviolet light source. Its response curve is as follows Figure 7 As shown, the long first electrode strip 61 has a longer charge collection area and thus has a higher sensitivity, but is saturated at a higher concentration because the output capacity of the operational amplifier is limited by the input voltage. The short first electrode strip 61 has a lower sensitivity and reaches saturation at a concentration about twice the saturation concentration of the long electrode.

[0055] This embodiment proves that the structure of the present invention can indeed be used for a simple and efficient micro photoionization sensor, and based on the shape of the electrode constructed on the vacuum ultraviolet window 2, the sensitivity of the photoionization sensor can be flexibly adjusted, which has a high practical value.

[0056] In the description of the present invention, it is necessary to understand that the terms "center", "length", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "inside", "outside", "peripheral", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred system or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0057] In the description of the present invention, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0058] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A vacuum ultraviolet lamp structure, characterized in that: The invention comprises a vacuum ultraviolet lamp glass shell (1), wherein one end of the vacuum ultraviolet lamp glass shell (1) is provided with an opening, wherein the opening is provided with a vacuum ultraviolet window (2) for sealing the opening, wherein the vacuum ultraviolet window (2) is sealedly connected to the vacuum ultraviolet lamp glass shell (1) so that a closed chamber (3) is formed inside the vacuum ultraviolet lamp glass shell (1), wherein the chamber (3) is filled with a working gas; a first contact piece (4), a second contact piece (5) and a collecting electrode structure (6) are fixedly provided on the surface of the vacuum ultraviolet window (2), wherein the collecting electrode structure (6) comprises at least two groups of mutually insulated electrode structures, wherein the first contact piece (4) and the second contact piece (5) are mutually insulated, and the first contact piece (4) and the second contact piece (5) are respectively electrically connected to the two groups of electrode structures; The collecting electrode structure (6) comprises a first electrode structure and a second electrode structure, wherein the first electrode structure and the second electrode structure are arranged between the first contact piece (4) and the second contact piece (5), the first electrode structure and the first contact piece (4) are electrically connected, and the second electrode structure and the second contact piece (5) are electrically connected; the first electrode structure comprises an arc-shaped first electrode arc (62), the second electrode structure comprises an arc-shaped second electrode arc (72) and an electrode ring (73), the electrode ring (73), the first electrode arc (62) and the second electrode arc (72) are concentrically arranged from inside to outside, the first electrode arc (62) is electrically connected to the first contact piece (4), and the electrode ring (73) and the second electrode arc (72) are electrically connected to the second contact piece (5).

2. A vacuum ultraviolet lamp structure according to claim 1, characterized in that: The vacuum ultraviolet window (2) is made of MgF2 or CaF2 or LiF.

3. A vacuum ultraviolet lamp structure according to claim 1, characterized in that: The collecting electrode structure (6), the first contact piece (4) and the second contact piece (5) are metal thin film structures fixed on the vacuum ultraviolet window (2) by chemical plating or thermal evaporation.

4. A method for preparing a vacuum ultraviolet lamp structure according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: forming a first contact piece (4), a second contact piece (5) and a collecting electrode structure (6) on a surface of one side of the vacuum ultraviolet window (2) by chemical plating or thermal evaporation; Step 2, bonding the vacuum ultraviolet window (2) after step 1 to one end of a glass tube used as a glass shell (1) of a vacuum ultraviolet lamp, so that the two are sealed and fixed; Step three, connect the other end of the glass tube to a vacuum pump, extract the air in the inner cavity of the glass tube and pump in the working gas, then use a high temperature flame to soften the end of the glass tube away from the vacuum ultraviolet window (2) and seal it to produce a vacuum ultraviolet lamp structure with an ion collecting electrode.

5. The method for preparing a vacuum ultraviolet lamp structure according to claim 4, characterized in that: The method of manufacturing a first contact piece (4), a second contact piece (5) and a collecting electrode structure (6) on a side surface of the vacuum ultraviolet window (2) by chemical electroplating or thermal evaporation in step 1 comprises: forming a metal film by chemical electroplating or thermal evaporation; and then manufacturing the metal film into the first contact piece (4), the second contact piece (5) and the collecting electrode structure (6) by an etching process.

6. The method for preparing a vacuum ultraviolet lamp structure according to claim 4, characterized in that: The method for forming a first contact piece (4), a second contact piece (5) and a collecting electrode structure (6) on one side surface of the vacuum ultraviolet window (2) by thermal evaporation in step 1 comprises: directly using a mask in the shape of the first contact piece (4), the second contact piece (5) and the collecting electrode structure (6) to cover one side surface of the vacuum ultraviolet window (2); and then evaporating a gold plating solution onto the vacuum ultraviolet window (2).

7. A photoionization sensor, characterized in that: The vacuum ultraviolet lamp comprises a vacuum ultraviolet lamp structure as claimed in any one of claims 1 to 3, and a bias circuit (8), an amplifier circuit (9), an excitation circuit (10), a voltage output circuit (11) and a power module (12), wherein the output end of the bias circuit (8) is electrically connected to the first contact member (4), the output end of the amplifier circuit (9) is electrically connected to the second contact member (5), the output end of the voltage output circuit (11) is electrically connected to the input end of the amplifier circuit (9), the output end of the excitation circuit (10) is electrically connected to an excitation coil (13) arranged outside the glass shell (1) of the vacuum ultraviolet lamp, and the output end of the power module (12) is electrically connected to the input end of the amplifier circuit (9) and the input end of the excitation circuit (10), respectively.

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