Calibration device for two-photon laser-induced fluorescence system

Abstract

The invention discloses a calibration device for a two-photon laser-induced fluorescence system, particularly relates to the technical field of laser calibration, and is technically characterized in that the device comprises an air pressure control device which is used for being connected with a vacuum calibration cavity to convey calibration gas into the vacuum calibration cavity and controlling the air pressure in the vacuum calibration cavity; the vacuum calibration cavity is used for placing calibration gas and receiving the laser light path, so that the calibration gas in the vacuum calibration cavity is excited to generate a fluorescent light path; the ionization device is used for ionizing hydrogen in the vacuum calibration cavity to obtain hydrogen atoms; and the detection device is used for receiving a fluorescent light path generated in the vacuum calibration cavity so as to complete calibration gas detection. A pair of discharge polar plates is installed in a vacuum calibration chamber and connected with an external high-voltage direct-current power supply through a high-voltage insulated wire, so that glow discharge is generated between the two discharge polar plates to ionize hydrogen molecules, and the ionized hydrogen molecules can form hydrogen atoms after being compounded to meet experimental calibration conditions.

Description

Technical Field

[0001] The invention relates to the technical field of laser calibration, and in particular to a calibration device for a two-photon laser induced fluorescence system. Background Art

[0002] Two-photon laser-induced fluorescence (TPL) diagnostics offer significant advantages in measuring neutral particle density due to its high precision and sensitivity. This technique provides detailed information about the distribution of neutral particles in plasmas, which is crucial for understanding and controlling plasma behavior. However, the precise application of TPL faces a major challenge: the calibration process. Traditional calibration methods rely on a suite of expensive, complex, and bulky equipment. These instruments are not only costly but also pose significant challenges in aligning the optical path and transporting the calibration system.

[0003] Regarding hydrogen, at normal temperature and pressure, hydrogen exists in the form of hydrogen molecules. However, when our goal is to measure hydrogen atoms, the devices usually used for calibration are different from the actual working conditions, and it is difficult to generate sufficient hydrogen atoms for calibration.

[0004] Especially in specialized environments, such as when installing within a tokamak, direct calibration within the tokamak is nearly impossible due to space limitations and unique operating conditions. Tokamaks are large-scale devices used for nuclear fusion research, and their complex internal environments often do not provide the conditions for direct calibration of two-photon laser-induced fluorescence systems. This requires researchers and engineers to complete calibration externally before installing the system within the tokamak, which undoubtedly increases the complexity and difficulty of the operation.

[0005] Therefore, the present invention aims to provide a calibration device for a two-photon laser induced fluorescence system to solve the above-mentioned related problems. Summary of the Invention

[0006] The technical problem to be solved by the present application is that the existing calibration device is different from the actual working condition, and it is difficult to produce enough hydrogen atoms for calibration.

[0007] The present application is realized by the following technical solutions: A calibration device for a two-photon laser-induced fluorescence system, the device comprising: A gas pressure control device for connecting to the vacuum calibration cavity to deliver calibration gas into the vacuum calibration cavity and controlling the gas pressure in the vacuum calibration cavity; A vacuum calibration cavity for placing calibration gas and receiving a laser light path to excite the calibration gas inside to generate a fluorescence light path; An ionization device for ionizing hydrogen gas in the vacuum calibration cavity to obtain hydrogen atoms; A detection device for receiving the fluorescence light path generated in the vacuum calibration cavity to complete calibration gas detection.

[0008] Further, the gas pressure control module includes a gas storage tank, a flow control valve, and a vacuum valve; the output port of the gas storage tank is connected to one end of the flow control valve, the other end of the flow control valve is connected to the vacuum calibration cavity; one end of the vacuum valve is connected to the vacuum calibration cavity, and the other end of the vacuum valve is connected to a molecular pump.

[0009] Further, the ionization device includes a plurality of insulating support columns and a plurality of discharge electrode plates, the plurality of insulating support columns are respectively vertically arranged on the two opposite inner side walls of the vacuum calibration cavity, and the plurality of discharge electrode plates are respectively arranged on one end of the insulating support column away from the inner side wall of the vacuum calibration cavity.

[0010] Further, the detection device uses a photomultiplier tube.

[0011] Further, one side of the vacuum calibration cavity is provided with an observation window.

[0012] Further, the vacuum calibration cavity is also provided with a vacuum gauge.

[0013] Further, the air pressure control device controls the air pressure in the vacuum calibration cavity to be in the range of 1*10 -4 -10 Pa.

[0014] Further, the plurality of discharge electrodes are arranged in parallel to each other, and the plurality of discharge electrodes are arranged opposite to each other in pairs.

[0015] Further, the calibration gas is hydrogen or krypton.

[0016] Further, the gas storage tank is also provided with a pressure reducing valve.

[0017] Compared with the prior art, the present application has the following advantages and beneficial effects: In the present application, by arranging the ionization device in the vacuum calibration cavity, the problem of generating hydrogen atoms required for calibration under normal temperature and pressure is solved; by using the calibration device of the present application, different environments and conditions can be adapted, and fast and accurate calibration capability is possessed to ensure that the two-photon laser-induced fluorescence diagnostic system can provide reliable measurement results at any location; the flexibility and practicality of the system are greatly improved, so that it can play a role in a wider application scenario, including but not limited to nuclear fusion research, industrial process control and other fields requiring accurate measurement of neutral particle density; through such a small and portable calibration device, researchers and engineers can more efficiently calibrate the system and reduce measurement errors caused by changes in location, thereby improving the overall experimental and research efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings: Figure 1 A module connection diagram of a calibration device for a two-photon laser-induced fluorescence system in the present embodiment; Figure 2 A structure diagram of an air pressure control device in the present embodiment; Figure 3 A structure diagram of an ionization device in the present embodiment; Figure 4 An installation diagram of a vacuum gauge in the present embodiment; Figure 5 An installation diagram of a pressure reducing valve in the present embodiment; Figure 6 A structure top view diagram of a calibration device for a two-photon laser-induced fluorescence system in the present embodiment.

[0019] Markings in the drawings and corresponding component names: 1, air pressure control device; 101, gas storage tank; 102, flow control valve; 103, vacuum valve; 2, vacuum calibration cavity; 3, ionization device; 301, insulating support column; 302, discharge electrode plate; 4, detection device; 5, observation window; 6, vacuum gauge; 7, pressure reducing valve. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with examples and drawings, the schematic embodiment of the present application and its description are only used to explain the present application, and do not limit the present application.

[0021] Example 1 Reference Figure 1 , Figure 1 A module connection diagram of a calibration device for a two-photon laser-induced fluorescence system is shown, wherein the device comprises: an air pressure control device 1, which is connected to a vacuum calibration cavity 2 to transport calibration gas into the vacuum calibration cavity 2, and controls the air pressure in the vacuum calibration cavity 2; it should be noted that in this embodiment, the air pressure control device 1 can be detachably connected to the vacuum calibration cavity 2, and the connection method adopts threaded connection, and in other embodiments, other connection methods can also be used, such as flange, sleeve, clamp, internal self-tightening and clamping connection, etc., which will not be described in detail here.

[0022] At the same time, in this embodiment, the calibration gas is hydrogen or krypton, which is determined according to actual needs, and is not limited here.

[0023] The vacuum calibration cavity 2 is used to place the calibration gas and receive the laser light path so that the calibration gas inside is excited to generate a fluorescence light path; it should be noted that in this embodiment, the vacuum calibration cavity 2 adopts a cubic structure, and in other embodiments, other structure designs can also be used, such as cylindrical and spherical structure designs, which will not be described in detail here; at the same time, it should be noted that in this embodiment, two openings connected to the air pressure control device 1 are excavated on both sides of the vacuum calibration cavity 2, which is a conventional technical means in the art, and will not be described in detail here; at the same time, an observation window 5 is provided on one side of the vacuum calibration cavity 2 for the entry or exit of the laser light path and the fluorescence light path, which adopts ultraviolet quartz plane glass, and in other embodiments, other materials can also be used, which will not be described in detail here.

[0024] An ionization device 3 is arranged in the vacuum calibration cavity 2 for ionizing the hydrogen gas in the vacuum calibration cavity 2 to obtain hydrogen atoms. It should be noted that in the embodiment, the ionization device 3 is detachably arranged in the vacuum calibration cavity 2 by screwing, and in other embodiments, other connection modes such as buckling or bolting can also be used, which is not limited here. Meanwhile, the ionization device 3 is connected to an external power supply device by wires, which is a conventional technical means in the art and is not described here.

[0025] A detection device 4 is arranged on one side of the vacuum calibration cavity 2 for receiving the fluorescent light path generated in the vacuum calibration cavity 2 to complete the calibration gas detection. It should be noted that in the embodiment, the detection device 4 is a photomultiplier, and in other embodiments, other detection devices 4 can also be used, which is not described here. Meanwhile, the detection device 4 is arranged at a certain angle with the outer wall of the vacuum calibration cavity 2, and in other embodiments, it can also be arranged according to the actual situation, which is not described here.

[0026] Embodiment 2 In the embodiment, a calibration device for a two-photon laser-induced fluorescence system is also provided, which comprises a gas pressure control device 1 connected to a vacuum calibration cavity 2 for delivering calibration gas into the vacuum calibration cavity 2 and controlling the gas pressure in the vacuum calibration cavity 2. It should be noted that in the embodiment, the gas pressure control device 1 can be detachably connected to the vacuum calibration cavity 2 by screwing, and in other embodiments, other connection modes such as flanges, sleeves, clamps, inner self-tightening, and clamping can also be used, which is not described here.

[0027] Meanwhile, in the embodiment, the calibration gas is hydrogen or krypton, which is determined according to the actual needs, which is not limited here.

[0028] The vacuum calibration cavity 2 is used for placing the calibration gas and receiving the laser light path to excite the calibration gas inside to generate a fluorescent light path. It should be noted that in the embodiment, the vacuum calibration cavity 2 adopts a cubic structure, and in other embodiments, other structure designs such as cylindrical and spherical structures can also be used, which is not described here. Meanwhile, it should be noted that in the embodiment, two openings connected to the gas pressure control device 1 are dug on both sides of the vacuum calibration cavity 2, which is a conventional technical means in the art and is not described here. Meanwhile, an observation window 5 is arranged on one side of the vacuum calibration cavity 2 for the laser light path and the fluorescent light path to enter or exit, which adopts ultraviolet quartz flat glass, and in other embodiments, other materials can also be used, which is not described here. An ionization device 3 is arranged in the vacuum calibration cavity 2 for ionizing the hydrogen gas in the vacuum calibration cavity 2 to obtain hydrogen atoms. It should be noted that in the embodiment, the ionization device 3 is detachably arranged in the vacuum calibration cavity 2 by screwing, and in other embodiments, other connection modes such as buckling or bolting can also be used, which is not limited here. At the same time, the ionization device 3 is connected with an external power supply device by wires, and the connection mode is a conventional technical means in the art, which is not described here.

[0029] A detection device 4 is arranged in the vacuum calibration cavity 2 for receiving the fluorescent light path generated in the vacuum calibration cavity 2 to complete the calibration gas detection. It should be noted that in the embodiment, the detection device 4 is a photomultiplier, and in other embodiments, other detection devices 4 can also be used, which is not described here. At the same time, the detection device 4 is arranged on one side of the vacuum calibration cavity 2 and is arranged at a certain angle with the outer wall of the vacuum calibration cavity 2, and in other embodiments, it can be arranged according to the actual situation, which is not described here.

[0030] In the embodiment, the ionization device 3 is arranged in the vacuum calibration cavity 2 for ionizing the hydrogen gas in the vacuum calibration cavity 2 to obtain hydrogen atoms. It should be noted that in the embodiment, the ionization device 3 is detachably arranged in the vacuum calibration cavity 2 by screwing, and in other embodiments, other connection modes such as buckling or bolting can also be used, which is not limited here. At the same time, the ionization device 3 is connected with an external power supply device by wires, and the connection mode is a conventional technical means in the art, which is not described here. Figure 2 Figure 2 The structure of the gas pressure control device 1 is shown in the schematic view, wherein the gas pressure control device 1 comprises a gas tank 101, a flow control valve 102 and a vacuum valve 103. The output port of the gas tank 101 is connected with one end of the flow control valve 102, and the other end of the flow control valve 102 is connected with the vacuum calibration cavity 2. One end of the vacuum valve 103 is connected with the vacuum calibration cavity 2, and the other end of the vacuum valve 103 is connected with a molecular pump.

[0031] It should be noted that in the embodiment, the volume of the gas tank 101 is 5L, and in other embodiments, other volumes of the gas tank 101 can also be used, which is not limited here. At the same time, in the embodiment, the gas tank 101 is connected with one opening of the vacuum calibration cavity 2 through the flow control valve 102. The vacuum valve 103 is connected at the other opening of the vacuum calibration cavity 2, and when it is needed to make the vacuum calibration cavity 2 in a vacuum state, the vacuum valve 103 will be connected with the molecular pump. At the same time, in the embodiment, the gas pressure control device 1 controls the gas pressure range in the vacuum calibration cavity 2 to be 1x10 -4 -10Pa, and by connecting the vacuum valve 103 with the molecular pump, the gas pressure in the vacuum calibration cavity 2 is lowered to 1x10 -4 Pa; by controlling the gas tank 101 and the flow control valve 102, the gas pressure in the vacuum calibration cavity 2 is adjusted between 1x10 -4 -10Pa according to the needs.

[0032] Embodiment 3 ​In the embodiment, a calibration device for a two-photon laser-induced fluorescence system is also provided, wherein the device comprises: a gas pressure control device 1, which is connected to a vacuum calibration cavity 2 to deliver calibration gas into the vacuum calibration cavity 2 and control the gas pressure in the vacuum calibration cavity 2. It should be noted that, in the embodiment, the gas pressure control device 1 can be detachably connected to the vacuum calibration cavity 2 by screw connection, and in other embodiments, other connection modes such as flange, sleeve, clamp, internal self-tightening, and clamping connection can also be used, which will not be described in detail here.

[0033] Meanwhile, in the embodiment, the calibration gas is hydrogen or krypton, which is determined according to actual needs, and will not be limited here.

[0034] The vacuum calibration cavity 2 is used to place the calibration gas and receive the laser light path so that the calibration gas inside is excited to generate a fluorescence light path. It should be noted that, in the embodiment, the vacuum calibration cavity 2 adopts a cubic structure, and in other embodiments, other structure designs such as cylindrical and spherical structures can also be used, which will not be described in detail here. Meanwhile, it should be noted that, in the embodiment, two openings connected to the gas pressure control device 1 are excavated on both sides of the vacuum calibration cavity 2, which is a conventional technical means in the field, and will not be described in detail here. Meanwhile, an observation window 5 is provided on one side of the vacuum calibration cavity 2 for the laser light path and the fluorescence light path to enter or exit, which adopts ultraviolet quartz flat glass, and in other embodiments, other materials can also be used, which will not be described in detail here.

[0035] The ionization device 3 is used to ionize the hydrogen in the vacuum calibration cavity 2 to obtain hydrogen atoms. It should be noted that, in the embodiment, the ionization device 3 is detachably installed in the vacuum calibration cavity 2 by screw connection, and in other embodiments, other connection modes such as buckle connection or bolt connection can also be used, which will not be limited here. Meanwhile, the ionization device 3 is connected to an external power supply device by wires, which is a conventional technical means in the field, and will not be described in detail here.

[0036] The detection device 4 is used to receive the fluorescence light path generated in the vacuum calibration cavity 2 to complete the detection of the calibration gas. It should be noted that, in the embodiment, the detection device 4 adopts a photomultiplier tube, and in other embodiments, other detection devices 4 can also be used, which will not be described in detail here. Meanwhile, the detection device 4 is placed on one side of the vacuum calibration cavity 2 and is arranged at a certain angle with the outer wall of the vacuum calibration cavity 2, and in other embodiments, it can be arranged according to actual conditions, which will not be described in detail here.

[0037] In the embodiment, the calibration device for the two-photon laser-induced fluorescence system comprises the above-mentioned components. Figure 3 , Figure 3A structural diagram of the ionization device 3 is shown, wherein the ionization device 3 comprises a plurality of insulating support columns 301 and a plurality of discharge electrode plates 302, the plurality of insulating support columns 301 are respectively vertically arranged at two opposite inner side walls of the vacuum calibration cavity 2, and the plurality of discharge electrode plates 302 are respectively arranged at one end of the insulating support columns 301 away from the inner side walls of the vacuum calibration cavity 2.

[0038] It should be noted that in the present embodiment, the insulating support columns 301 are made of plastic material, and in other embodiments, materials such as rubber can also be used, which will not be described in detail here; at the same time, one end of the insulating support column 301 is vertically arranged at one side of the discharge electrode plate 302; the number of discharge electrode plates 302 and insulating support columns is determined according to the actual situation, which will not be limited here.

[0039] Embodiment 4 In the present embodiment, a calibration device for a two-photon laser-induced fluorescence system is also provided, wherein the device comprises: a gas pressure control device 1 for connecting with the vacuum calibration cavity 2 to transport calibration gas into the vacuum calibration cavity 2, and controlling the gas pressure in the vacuum calibration cavity 2; it should be noted that in the present embodiment, the gas pressure control device 1 can be detachably connected with the vacuum calibration cavity 2, and the connection mode adopts threaded connection, and in other embodiments, other connection modes can also be used, such as flange, sleeve, clamp, internal self-tightening and clamping connection, which will not be described in detail here.

[0040] At the same time, in the present embodiment, the calibration gas is hydrogen or krypton, which is determined according to the actual demand, which will not be limited here.

[0041] The vacuum calibration cavity 2 is used to place the calibration gas and receive the laser light path so that the calibration gas inside is excited to generate fluorescence light path; it should be noted that in the present embodiment, the vacuum calibration cavity 2 adopts a cubic structure, and in other embodiments, other structure designs can also be used, such as cylindrical and spherical structure designs, which will not be described in detail here; at the same time, it should be noted that in the present embodiment, two openings are excavated on both sides of the vacuum calibration cavity 2 for connecting with the gas pressure control device 1, which is a conventional technical means in the art, which will not be described in detail here; at the same time, an observation window 5 is provided on one side of the vacuum calibration cavity 2 for the laser light path and the fluorescence light path to enter or exit, which adopts ultraviolet quartz plane glass, and in other embodiments, other materials can also be used, which will not be described in detail here.

[0042] An ionization device 3 is arranged in the vacuum calibration cavity 2 for ionizing the hydrogen gas in the vacuum calibration cavity 2 to obtain hydrogen atoms. It should be noted that in the embodiment, the ionization device 3 is detachably arranged in the vacuum calibration cavity 2 by screwing, and in other embodiments, other connection modes such as buckling or bolting can also be used, which is not limited here. Meanwhile, the ionization device 3 is connected with an external power supply device by wires, which is a conventional technical means in the art and is not described here.

[0043] A detection device 4 is arranged on one side of the vacuum calibration cavity 2 and is arranged at a certain angle with the outer wall of the vacuum calibration cavity 2 for receiving the fluorescent light path generated in the vacuum calibration cavity 2 to complete the calibration gas detection. It should be noted that in the embodiment, the detection device 4 is a photomultiplier, and in other embodiments, other detection devices 4 can also be used, which is not limited here.

[0044] As shown in FIG. 1, the vacuum calibration cavity 2 is provided with a vacuum gauge 6 at the top. Figure 4 It should be noted that in the embodiment, the accurate air pressure reading in the vacuum calibration cavity 2 can be obtained by reading the vacuum gauge 6, and in other embodiments, other devices for obtaining air pressure readings can also be used, which is not limited here.

[0045] Embodiment 5

[0046] In the embodiment, a calibration device for a two-photon laser-induced fluorescence system is also provided, wherein the device comprises: an air pressure control device 1 connected with the vacuum calibration cavity 2 for conveying calibration gas into the vacuum calibration cavity 2 and controlling the air pressure in the vacuum calibration cavity 2. It should be noted that in the embodiment, the air pressure control device 1 is detachably connected with the vacuum calibration cavity 2 by screwing, and in other embodiments, other connection modes such as flanges, sleeves, clamps, inner self-tightening, and opposite clamping can also be used, which is not limited here. Meanwhile, in the embodiment, the calibration gas is hydrogen or krypton, which is determined according to actual needs, which is not limited here.

[0047]

[0048] ​The vacuum calibration cavity 2 is used for placing the calibration gas and receiving the laser light path so that the calibration gas inside is excited to generate the fluorescence light path; it should be noted that in the embodiment, the vacuum calibration cavity 2 adopts a cubic structure, and in other embodiments, other structure designs such as cylindrical and spherical structure designs can also be adopted, which will not be described in detail here; at the same time, it should be noted that in the embodiment, two openings connected with the gas pressure control device 1 are excavated on both sides of the vacuum calibration cavity 2, which is a conventional technical means in the field, and will not be described in detail here; at the same time, an observation window 5 is arranged on one side of the vacuum calibration cavity 2 for the laser light path and the fluorescence light path to enter or exit, which adopts ultraviolet quartz flat glass, and in other embodiments, other materials can also be used, which will not be described in detail here.

[0049] The ionization device 3 is used for ionizing the hydrogen gas in the vacuum calibration cavity 2 to obtain hydrogen atoms; it should be noted that in the embodiment, the ionization device 3 is detachably installed in the vacuum calibration cavity 2, and the connection mode adopts threaded connection, and in other embodiments, other connection modes such as buckle connection or bolt connection can also be adopted, which will not be limited here; at the same time, the ionization device 3 is connected with the external power supply device through the wire, and the connection mode is a conventional technical means in the field, which will not be described in detail here.

[0050] The detection device 4 is used for receiving the fluorescence light path generated in the vacuum calibration cavity 2 to complete the calibration gas detection; it should be noted that in the embodiment, the detection device 4 adopts a photomultiplier, and in other embodiments, other detection devices 4 can also be adopted, which will not be described in detail here; at the same time, the detection device 4 is placed on one side of the vacuum calibration cavity 2 and is arranged at a certain angle with the outer side wall of the vacuum calibration cavity 2, and in other embodiments, it can also be set according to the actual situation, which will not be described in detail here.

[0051] The gas pressure control device 1 includes a gas storage tank 101, a flow control valve 102 and a vacuum valve 103; the output port of the gas storage tank 101 is connected with one end of the flow control valve 102, the other end of the flow control valve 102 is connected with the vacuum calibration cavity 2; one end of the vacuum valve 103 is connected with the vacuum calibration cavity 2, and the other end of the vacuum valve 103 is connected with a molecular pump; at the same time, the gas storage tank 101 is also provided with a pressure reducing valve 7.

[0052] It should be noted that in the present embodiment, the volume of the gas tank 101 is 5L, and in other embodiments, other volumes of the gas tank 101 can also be used, which is not limited here; at the same time, in the present embodiment, the gas tank 101 is connected with one opening of the vacuum calibration cavity 2 through the flow control valve 102; the vacuum valve 103 is connected at the other opening of the vacuum calibration cavity 2, and when it is needed to make the vacuum calibration cavity 2 in a vacuum state, the vacuum valve 103 will be connected with the molecular pump.

[0053] At the same time, in the present embodiment, the gas pressure control device 1 controls the gas pressure range in the vacuum calibration cavity 2 to be 1x10 -4 -10Pa, and by connecting the vacuum valve 103 with the molecular pump, the gas pressure in the vacuum calibration cavity 2 is lowered to 1x10 -4 Pa; by controlling the gas tank 101 and the flow control valve 102, the gas pressure in the vacuum calibration cavity 2 is adjusted between 1x10 -4 -10Pa according to the needs.

[0054] At the same time, it should also be noted that, as shown in Figure 5 , Figure 5 shows the installation schematic diagram of the pressure reducing valve 7, and in the present embodiment, the pressure reducing valve 7 for reducing the pressure of the gas tank 101 is arranged on the gas tank 101.

[0055] Embodiment 6 In the present embodiment, a calibration device for a two-photon laser-induced fluorescence system is also provided, wherein the device comprises: a gas pressure control device 1, which is used to be connected with a vacuum calibration cavity 2 to deliver calibration gas into the vacuum calibration cavity 2, and to control the gas pressure in the vacuum calibration cavity 2; it should be noted that in the present embodiment, the gas pressure control device 1 can be detachably connected with the vacuum calibration cavity 2, and the connection mode adopts threaded connection, and in other embodiments, other connection modes can also be used, such as flange, sleeve, clamp, internal self-tightening and clamping connection, etc., which is not limited here.

[0056] At the same time, in the present embodiment, the calibration gas uses hydrogen or krypton, which is specifically determined according to the actual needs, which is not limited here.

[0057] A vacuum calibration cavity 2 is used to place the calibration gas and receive the laser light path so that the calibration gas inside is excited to generate the fluorescence light path; it should be noted that in the embodiment, the vacuum calibration cavity 2 adopts a cubic structure, and in other embodiments, other structure designs such as cylindrical and spherical structure designs can also be adopted, which will not be described in detail here; at the same time, it should be noted that in the embodiment, two openings connected with the gas pressure control device 1 are excavated on the two sides of the vacuum calibration cavity 2, which is a conventional technical means in the field, and will not be described in detail here; at the same time, an observation window 5 is arranged on one side of the vacuum calibration cavity 2 for the laser light path and the fluorescence light path to enter or exit, which adopts ultraviolet quartz plane glass, and in other embodiments, other materials can also be used, which will not be described in detail here.

[0058] An ionization device 3 is used to ionize the hydrogen gas in the vacuum calibration cavity 2 to obtain hydrogen atoms; it should be noted that in the embodiment, the ionization device 3 is detachably installed in the vacuum calibration cavity 2, and the connection mode adopts threaded connection, and in other embodiments, other connection modes such as buckle connection or bolt connection can also be adopted, which will not be limited here; at the same time, the ionization device 3 is connected with the external power supply device through wires, and the connection mode is a conventional technical means in the field, which will not be described in detail here.

[0059] A detection device 4 is used to receive the fluorescence light path generated in the vacuum calibration cavity 2 to complete the calibration gas detection; it should be noted that in the embodiment, the detection device 4 adopts a photomultiplier tube, and in other embodiments, other detection devices 4 can also be used, which will not be described in detail here; at the same time, the detection device 4 is placed on one side of the vacuum calibration cavity 2 and is arranged at a certain angle with the outer side wall of the vacuum calibration cavity 2, and in other embodiments, it can be arranged according to the actual situation, which will not be described in detail here.

[0060] The ionization device 3 includes a plurality of insulating support columns 301 and a plurality of discharge electrode plates 302, the plurality of insulating support columns 301 are respectively vertically arranged on the two opposite inner side walls of the vacuum calibration cavity 2, and the plurality of discharge electrode plates 302 are respectively arranged on one end of the insulating support column 301 away from the inner side wall of the vacuum calibration cavity 2.

[0061] It should be noted that in the embodiment, the insulating support column 301 adopts a plastic material, and in other embodiments, a rubber material or the like can also be used, which will not be described in detail here; at the same time, one end of the insulating support column 301 is vertically arranged on one side of the discharge electrode plate 302; the number of the discharge electrode plate 302 is two, and the number of the insulating support column 301 is four, and in other embodiments, other numbers can also be used, which will not be limited here.

[0062] The two discharge electrodes 302 are arranged parallel to each other and opposite to each other.

[0063] It should be noted that, in this embodiment, a pair of discharge plates 302 are installed inside the vacuum calibration chamber 2, and the discharge plates 302 are connected to an external high-voltage DC power supply through a high-voltage insulated wire, so that glow discharge can be generated between the two discharge plates 302 to ionize hydrogen molecules. The ionized hydrogen molecules will recombine to form hydrogen atoms to meet the experimental calibration conditions.

[0064] Example 7 In this embodiment, see Figure 6 , Figure 6 A structural schematic diagram of a calibration device for a two-photon laser induced fluorescence system is shown, wherein the device includes: an air pressure control device 1, which is used to connect with a vacuum calibration chamber 2 to deliver calibration gas into the vacuum calibration chamber 2 and control the air pressure in the vacuum calibration chamber 2; it should be noted that, in this embodiment, the air pressure control device 1 can be detachably connected to the vacuum calibration chamber 2, and the connection method is a threaded connection. In other embodiments, other connection methods can also be used, such as flanges, ferrules, clamps, internal self-tightening and clamping connections, which will not be described in detail here.

[0065] Meanwhile, in this embodiment, the calibration gas uses hydrogen or krypton, which is determined according to actual needs and is not subject to excessive restrictions here.

[0066] The vacuum calibration chamber 2 is used to place calibration gas and receive the laser light path so that the calibration gas inside it is excited to generate a fluorescent light path. It should be noted that in the present embodiment, the vacuum calibration chamber 2 adopts a cubic structure. In other embodiments, other structural designs may be adopted, such as cylindrical and spherical structural designs, which are not described in detail here. At the same time, it should be noted that in the present embodiment, two openings connected to the air pressure control device 1 are opened on both sides of the vacuum calibration chamber 2. This technical means is a conventional technical means in this field and is not described in detail here. At the same time, an observation window 5 is provided on one side of the vacuum calibration chamber 2 for the injection or emission of the laser light path and the fluorescent light path. The observation window 5 adopts ultraviolet quartz plane glass. In other embodiments, other materials may be used. It is not described in detail here. The ionization device 3 is used to ionize the hydrogen in the vacuum calibration chamber 2 to obtain hydrogen atoms. It should be noted that in this embodiment, the ionization device 3 can be detachably installed in the vacuum calibration chamber 2, and the connection method adopts a threaded connection. In other embodiments, other connection methods can also be adopted, such as a snap connection or a bolt connection, etc., and no excessive restrictions are made here. At the same time, the ionization device 3 is connected to the external power supply equipment through an electric wire. Its connection method is a conventional technical means in this field and will not be elaborated on here.

[0067] A detection device 4 is arranged to receive the fluorescent light path generated in the vacuum calibration cavity 2 to complete the calibration gas detection. It should be noted that in the embodiment, the detection device 4 is a photomultiplier tube, and in other embodiments, other detection devices 4 can also be used, which will not be described in detail here. At the same time, the detection device 4 is arranged on one side of the vacuum calibration cavity 2 and is arranged at a certain angle with the outer side wall of the vacuum calibration cavity 2. In other embodiments, it can also be arranged according to the actual situation, which will not be described in detail here.

[0068] The gas pressure control device 1 includes a gas storage tank 101, a flow control valve 102, and a vacuum valve 103. The output port of the gas storage tank 101 is connected to one end of the flow control valve 102, and the other end of the flow control valve 102 is connected to the vacuum calibration cavity 2. One end of the vacuum valve 103 is connected to the vacuum calibration cavity 2, and the other end of the vacuum valve 103 is connected to a molecular pump.

[0069] It should be noted that in the embodiment, the volume of the gas storage tank 101 is 5L, and in other embodiments, other volumes of the gas storage tank 101 can also be used, which will not be limited here. At the same time, in the embodiment, the gas storage tank 101 is connected to one opening of the vacuum calibration cavity 2 through the flow control valve 102. The vacuum valve 103 is connected to the other opening of the vacuum calibration cavity 2, and when it is necessary to make the vacuum calibration cavity 2 in a vacuum state, the vacuum valve 103 will be connected to the molecular pump. At the same time, in the embodiment, the gas pressure control device 1 controls the gas pressure range in the vacuum calibration cavity 2 to be 1x10 -4 -10Pa, and by connecting the vacuum valve 103 to the molecular pump, the gas pressure in the vacuum calibration cavity 2 is lowered to 1x10 -4 -10Pa. By controlling the gas storage tank 101 and the flow control valve 102, the gas pressure in the vacuum calibration cavity 2 can be adjusted between 1x10 -4 -10Pa according to the needs. It should be noted that in the embodiment, a pressure reducing valve 7 is arranged on the gas storage tank 101 for pressure reduction of the gas storage tank 101.

[0070] The ionization device 3 includes a plurality of insulating support columns 301 and a plurality of discharge electrode plates 302. The plurality of insulating support columns 301 are respectively arranged vertically on the two opposite inner side walls of the vacuum calibration cavity 2, and the plurality of discharge electrode plates 302 are respectively arranged on one end of the insulating support column 301 away from the inner side wall of the vacuum calibration cavity 2.

[0071] It should be noted that in the present embodiment, the insulating support column 301 is made of plastic material, and in other embodiments, it can also be made of rubber and other materials, which will not be described here; at the same time, one end of the insulating support column 301 is vertically arranged on one side of the discharge electrode plate 302; the number of discharge electrode plates 302 is two, and the number of insulating support columns 301 is four, and in other embodiments, other numbers can also be used, which will not be limited here.

[0072] The top of the vacuum calibration cavity 2 is also provided with a vacuum gauge 6.

[0073] It should be noted that in the present embodiment, the accurate air pressure reading in the vacuum calibration cavity 2 can be known by reading the vacuum gauge 6; in other embodiments, other devices for obtaining air pressure readings can also be used, which will not be limited here.

[0074] The two discharge electrode plates 302 are arranged in parallel and opposite to each other.

[0075] Specifically, the calibration device provided in the present embodiment occupies a space of less than 0.1m x 0.1m x 0.6m, and can be placed in a relatively narrow space; by installing a pair of discharge electrode plates 302 inside the vacuum calibration cavity 2, the discharge electrode plates 302 are connected to the external high-voltage direct-current power supply through high-voltage insulating wires, which can produce glow discharge ionization of hydrogen molecules between the two discharge electrode plates 302, and the ionized hydrogen molecules will form hydrogen atoms after recombination to meet the experimental calibration conditions.

[0076] Working principle: example one: the vacuum valve 103 is connected to the air pump and the molecular pump, and the air pressure in the vacuum calibration cavity 2 is reduced to 1x10 -4 Pa, then the vacuum valve 103 is closed, and the air pump and the molecular pump are removed. The whole device system is moved to the front of the two-photon laser-induced fluorescence system, and the position is adjusted so that the laser can be incident into the vacuum calibration cavity 2 through the observation window 5, and the induced fluorescence can be received by the detection device 4 after passing through the observation window 5, and the optical path is as shown in Figure 6 After the position adjustment of the calibration device is completed, the flow control valve 102 is opened, so that the vacuum calibration cavity 2 is filled with krypton gas, and the vacuum gauge 6 reads 1x10 -1Pa. Set the laser wavelength to 204.00 nm, start the laser to emit laser, use the detection device 4 to get the fluorescence intensity, record the laser wavelength and fluorescence intensity value. Repeat the above steps, so that the laser wavelength from 204.00 nm interval 0.01 nm to 205.00 nm, get the fluorescence intensity corresponding to different laser wavelength, draw the laser wavelength-fluorescence intensity graph, determine the higher fluorescence intensity range. In the higher fluorescence intensity range, adjust the laser wavelength every 0.001 nm, get more accurate laser wavelength-fluorescence intensity graph, use Gaussian function to curve fitting. Thus, the spectrum line calibration of krypton atom is completed.

[0077] Example two: vacuum valve 103 connects air pump and molecular pump, the pressure in the vacuum calibration cavity 2 is reduced to 1x10 -4 Pa, then close the vacuum valve 103, remove the air pump and molecular pump connection. The whole device system is moved to the front of the two-photon laser-induced fluorescence system, adjust the position of the calibration device, so that the laser can be incident into the vacuum calibration cavity 2 through the observation window 5, and the induced fluorescence can be received by the detection device 4 after passing through the observation window 5. After completing the position adjustment of the calibration device, open the flow control valve 102, so that the vacuum calibration cavity 2 chamber is filled with krypton gas, and the vacuum gauge 6 reads 1x10 -1 Pa. According to the above calibrated krypton atom spectrum line, adjust the laser wavelength to the laser wavelength corresponding to the highest fluorescence intensity. Start the laser, record the gas pressure and fluorescence intensity value, complete a test. Open the flow control valve 102, fill the vacuum calibration cavity 2 chamber with krypton gas, so that the vacuum gauge 6 reads 2x10 -1 Pa, 3x10 -1 Pa, 4x10 -1 Pa, 5x10 -1 Pa, repeat the above test steps, record the fluorescence intensity value corresponding to different gas pressure. Use the ideal gas state equation to get the corresponding neutral particle density value through the gas pressure, make the neutral particle density-fluorescence intensity value graph, and make linear fitting. Thus, the neutral particle gas density-fluorescence intensity system calibration is completed.

[0078] Example three: vacuum valve 103 connects air pump and molecular pump, the pressure in the vacuum calibration cavity 2 is reduced to 1x10 -4Pa, then the vacuum valve 103 is closed, the gas pump and the molecular pump are removed. The whole system is carried to the front of the two-photon laser-induced fluorescence system, the ionization device 3 is connected to the high-voltage power supply, the hydrogen molecules are ionized by the discharge electrode plate 302, and the hydrogen atoms are generated in the vacuum calibration cavity 2. Then the laser is incident into the vacuum calibration cavity 2 through the observation window 5, the induced fluorescence can be received by the detection device 4 after passing through the observation window 5, the different laser wavelengths are adjusted, the fluorescence intensity change is recorded, and the calibration hydrogen atom excitation spectrum line characteristics are obtained. The fluorescence intensity change is compared with the fluorescence intensity change of the krypton atom in example two, and the hydrogen atom density is obtained. Thus, the calibration result of the two-photon laser-induced fluorescence system is completed.

[0079] The above specific embodiments further illustrate the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A calibration device for a two-photon laser-induced fluorescence system, characterized in that: The device includes: An air pressure control device is used to connect to the vacuum calibration chamber to deliver calibration gas into the vacuum calibration chamber and control the air pressure in the vacuum calibration chamber; A vacuum calibration chamber, used for placing calibration gas and receiving the laser light path so that the calibration gas inside it is excited to generate a fluorescent light path; an ionization device, used to ionize the hydrogen gas in the vacuum calibration chamber to obtain hydrogen atoms; The detection device is used to receive the fluorescent light path generated in the vacuum calibration chamber to complete the calibration gas detection.

2. A calibration device for a two-photon laser induced fluorescence system according to claim 1, characterized in that: The air pressure control module includes an air storage tank, a flow control valve and a vacuum valve; the output port of the air storage tank is connected to one end of the flow control valve, and the other end of the flow control valve is connected to the vacuum calibration chamber; one end of the vacuum valve is connected to the vacuum calibration chamber, and the other end of the vacuum valve is connected to a molecular pump.

3. The calibration device for a two-photon laser-induced fluorescence system according to claim 1, characterized in that: The ionization device includes multiple insulating support columns and multiple discharge electrode plates. The multiple insulating support columns are respectively vertically arranged on two opposite inner walls of the vacuum calibration chamber, and the multiple discharge electrode plates are respectively arranged on one end of the insulating support columns away from the inner wall of the vacuum calibration chamber.

4. The calibration device for a two-photon laser-induced fluorescence system according to claim 1, characterized in that: The detection device adopts a photomultiplier tube.

5. The calibration device for a two-photon laser induced fluorescence system according to claim 1, characterized in that: An observation window is provided on one side of the vacuum calibration chamber.

6. The calibration device for a two-photon laser induced fluorescence system according to claim 1, characterized in that: The vacuum calibration chamber is also provided with a vacuum gauge.

7. The calibration device for a two-photon laser induced fluorescence system according to claim 1, characterized in that: The air pressure control device controls the air pressure in the vacuum calibration chamber to a range of 1×10 -4 -10Pa.

8. The calibration device for a two-photon laser-induced fluorescence system according to claim 1, characterized in that: The plurality of discharge electrode plates are arranged parallel to each other, and the plurality of discharge electrode plates are arranged opposite to each other in pairs.

9. The calibration device for a two-photon laser-induced fluorescence system according to claim 1, characterized in that: The calibration gas used is hydrogen or krypton.

10. The calibration device for a two-photon laser induced fluorescence system according to claim 1, characterized in that: The gas tank is also equipped with a pressure reducing valve.

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