CN214584916U

CN214584916U - Aerosol single-particle imprisoning device and spectral detection system

Info

Publication number: CN214584916U
Application number: CN202120807956.8U
Authority: CN
Inventors: 俞文杰; 刘玉柱; 孙仲谋; 杨明磊; 万恩来; 张兴龙; 于玮; 葛一凡
Original assignee: Nanjing University of Information Science and Technology
Current assignee: Nanjing University of Information Science and Technology
Priority date: 2021-04-20
Filing date: 2021-04-20
Publication date: 2021-11-02
Anticipated expiration: 2031-04-20

Abstract

The utility model discloses an aerosol single-particle imprisoning device, which comprises a vacuum chamber, a conduit, an electron gun, a horizontal charged plate electrode, a charged cylinder and a vertical charged plate electrode, wherein the conduit, the electron gun, the horizontal charged plate electrode, the charged cylinder and the vertical charged plate electrode are positioned in the vacuum chamber; the two electrified cylinders are coaxially arranged; the two horizontal charged electrode plates are arranged in the two charged cylinders in parallel up and down; the two vertical charged electrode plates are respectively arranged in the two charged cylinders and are vertical to the horizontal charged electrode plates, and the vertical charged electrode plate at one end close to the guide pipe is provided with small holes for aerosol particles to pass through; the electron gun is arranged between the guide pipe and the horizontal electrode plate. The utility model discloses utilize aerosol particle imprisoning device, can effectively imprison the fixed position in real empty room with single aerosol particle to accurately shine by LIBS laser, survey its composition. The device is combined with an LIBS detection device to form a set of complete system, so that the experiment of the LIBS technology for detecting solid aerosol particles in the atmosphere can be smoothly carried out. The utility model also provides a spectrum detection system.

Description

Aerosol single-particle imprisoning device and spectral detection system

Technical Field

The utility model relates to an electron emission technology, concretely relates to compound electric field imprisons electrified particle technique and laser-induced breakdown spectroscopy detection technique.

Background

In the past, with the development of industry and the advancement of science and technology, the problem of air pollution is becoming more serious. Aerosols are gaseous dispersions of solid or liquid particles suspended in a gaseous medium and are relatively serious pollutants in the atmosphere. Therefore, rapid component detection of aerosols is of great importance.

Laser-induced breakdown spectroscopy (LIBS) is a highly sensitive detection technique. It uses lens to focus high energy laser pulse and irradiates sample to generate high temperature plasma instantly. The chemical composition of the sample to be detected can be known by collecting the spectra of these plasmas by a spectrometer, and the technique is often used for detecting aerosol. In an actual LIBS detection experiment, solid aerosol particles are separated by a single particle and detected in a vacuum chamber, however, because the solid aerosol freely moves in the vacuum chamber, the uncertainty of the position of the solid aerosol makes it difficult to focus a laser focus on a sample, and the difficulty of the LIBS detection experiment is greatly increased. Therefore, it is of no experimental significance to the LIBS how to trap (i.e., stably balance, positionally fix) single particle aerosol particles at a given location in the vacuum chamber.

Disclosure of Invention

The utility model aims at solving the defect that exists among the prior art, provide the trapping device that can effectively fix single granule aerosol position to can shine through the LIBS laser accuracy, confirm to detect the granule composition.

In order to achieve the purpose, the utility model provides an aerosol single-particle imprisoning device, which comprises a vacuum chamber, a guide pipe, an electron gun, a horizontal charged electrode plate, a charged cylinder and a vertical charged electrode plate, wherein the guide pipe, the electron gun, the horizontal charged electrode plate, the charged cylinder and the vertical charged electrode plate are positioned in the vacuum chamber; the two electrified cylinders are coaxially arranged; the two horizontal charged electrode plates are arranged in the two charged cylinders in parallel up and down; the two vertical charged electrode plates are respectively arranged in the two charged cylinders and are vertical to the horizontal charged electrode plates, and the vertical charged electrode plate at one end close to the guide pipe is provided with small holes for aerosol particles to pass through; the electron gun is arranged between the guide pipe and the horizontal electrode plate.

The utility model discloses an electron gun lets out and penetrates behind aerosol particle electrification, produces the electric field of offsetting granule gravity through the horizontal electrified polar plate, makes its movement track keep the level, makes the aerosol that has the initial velocity slow down via the electric field that slows down that vertical electrified polar plate produced to the aerosol particle after utilizing the balanced electric field power that electrified drum produced to return to zero the speed is in stable balanced state at appointed imprison position, thereby effectively imprisons aerosol particle.

Furthermore, the symmetrical axes of the two horizontal charged electrode plates are superposed with the central axis of the charged cylinder and the emergent track of the aerosol single particles in the guide pipe; the small hole on the vertical charged electrode plate is positioned on the central axis of the charged cylinder. Effectively ensuring the horizontal movement track of the aerosol particles.

Further, the aerosol single-particle trapping device further comprises a controller; the controller is arranged outside the vacuum chamber and is respectively and electrically connected with the guide pipe, the electron gun, the horizontal charged electrode plate, the charged cylinder and the vertical charged electrode plate. The controller is used for effectively adjusting the gravity counteracting electric field force and the deceleration electric field force.

Further, the aerosol single-particle trapping device also comprises a speed sensor; the speed sensor is arranged at the outlet of the guide pipe and is connected with the controller. Through the detection to the aerosol initial velocity, conveniently carry out system adjustment to speed reduction electric field force to reach appointed imprisoning position.

The utility model also provides a spectral detection system comprising the aerosol single-particle trapping device, which also comprises a laser-induced breakdown spectrometer; the laser induced breakdown spectrometer is arranged outside a vacuum chamber of the aerosol single-particle trapping device, and emergent laser is focused between the two electrified cylinders.

Further, the laser induced breakdown spectrometer comprises a laser, an electronic laser focusing device, a spectrum detecting head, an ICCD detector and a spectrometer; laser emitted by the laser passes through the electronic laser focusing device and then enters the vacuum chamber, aerosol particles emit a spectrum after being irradiated by a laser focus, and the aerosol particles are transmitted into the ICCD detector and the spectrometer through the optical fiber after being detected by the spectrum detector head.

Furthermore, a glass window for laser incidence is arranged on the chamber wall of the vacuum chamber and between the two electrified cylinders.

Further, the laser induced breakdown spectrometer further comprises a particle position detector; the particle position detector is arranged in a vacuum chamber of the aerosol single-particle trapping device and is connected with the spectrometer in a control mode.

Compared with the prior art, the utility model has the following advantages:

the utility model discloses utilize aerosol particle imprisoning device, can effectively imprison the fixed position in real empty room with single aerosol particle to accurately shine by LIBS laser, survey its composition. The device is combined with an LIBS detection device to form a set of complete system, so that the experiment of the LIBS technology for detecting solid aerosol particles in the atmosphere can be smoothly carried out.

1. The utility model relates to a one set of novel laser-induced breakdown spectroscopy detection system who is equipped with single granule aerosol imprisons device can realize imprisoning under vacuum environment to single aerosol granule, can let the aerosol granule stable balance who does not receive the contact force appoint the position in real empty room, provides one set of perfect system for LIBS technical detection single granule aerosol.

2. Due to the particularity of the designed trapping electric field, particles which are slightly disturbed at the balance position can be rebalanced, so that the requirement on the accuracy of the speed reducing device is not high, aerosol particles only need to be approximately zero at the balance position, the speed reducing electric field is removed, and the particles can be stably balanced.

Drawings

Fig. 1 is a schematic structural diagram of the spectrum detection system of the present invention;

FIG. 2 is a schematic view of the aerosol particle confinement device of FIG. 1;

FIG. 3 is a model of the force-stabilized balance principle of aerosol in the trapping electric field generated by the electrified cylinder of FIG. 2;

FIG. 4 is a schematic diagram of the electric field generated by the aerosol particle confinement device of FIG. 2;

fig. 5 is a flow chart of a method for detecting aerosol by using the device of the present invention.

In the figure, 1-guide tube, 2-speed sensor, 3, 4-electron gun, 5, 6-horizontal charged electrode plate, 7, 8-charged cylinder, 9, 10-vertical charged electrode plate, 11-laser, 12-aerosol particle, 13-controller, 14-controller external connecting wire, 15-vacuum chamber, 16-laser, 17-plane mirror, 18-glass window, 19-electronic laser focusing device, 20-particle position detector, 21-spectrum detecting head, 22-optical fiber, 23-ICCD detector, 24-spectrometer and 25-control signal transmission line.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

The utility model discloses a LIBS technique carries out aerosol particle detection. The LIBS experiment detects the separated single particle aerosol particles, which are only subjected to gravity in a vacuum chamber because the aerosol particles do not exhibit electrical properties. Therefore, the electron gun is firstly used for emitting electrons to the single-particle aerosol, so that the single-particle aerosol is charged with negative charges, and the stress condition of the single-particle aerosol can be controlled by an electric field.

As shown in FIG. 1, the spectrum detection system of the present invention comprises an aerosol particle trapping device and a laser-induced breakdown spectrometer. The laser induced breakdown spectrometer emits laser by a laser 16, and the laser is reflected by a plane mirror 17 and then emitted into the aerosol particle trapping device. The aerosol particle confinement device is integrally provided with a vacuum chamber 15, and a glass window 18 is formed in the chamber wall of the vacuum chamber 15, so that laser light enters and is focused at the confinement position of the aerosol particle 12 through an electronic laser focuser 19. The particle position detector 20 can be fixedly arranged in the vacuum chamber 15 through a support, can detect the position of aerosol particles, provides particle position information for the electronic laser focalizer 19, and adjusts the electric field of the aerosol particle trapping device. After the aerosol particles 12 are irradiated by the laser focus, the spectrum emitted by the aerosol particles is detected by the spectrum detecting head 21 and transmitted to the ICCD detector 23 and the spectrometer 24 through the optical fiber 22, and then converted into digital signals for further analysis.

The aerosol particle trapping device has a specific structure as shown in FIG. 2, the whole device is placed in a vacuum chamber 15, and a single aerosol particle is separated and then ejected from a conduit 1 with an initial velocity v₀. After the aerosol particles are emitted, the data such as the velocity and the emitting time of the particles are obtained by the velocity sensor 2 and transmitted to the controller 13, so that the moving velocity and the time information of the aerosol particles are provided for the subsequent work of the electron gun and the work of the imprisoned electric field. After the aerosol particles are ejected, the electron guns 3 and 4 are arranged on the motion trail of the aerosol particles to emit a large number of electrons, and after the electrons are ejected to the aerosol particles, the aerosol particles are charged with a large number of negative charges. After the particles are charged, the particles continuously move forwards along the original track and enter between the horizontal charged horizontal polar plates 5 and 6 which are parallel up and down, the electric field force generated by the polar plates is vertically upward and offset with the gravity of aerosol particles, and therefore the particles can linearly move along the original track at a constant speed. The aerosol particle confinement device is designed with a confinement electric field, which comprises

charged cylinders

7, 8 and vertical charged electrode plates 9, 10. The charged cylinder is a double-cylinder type electric field generating device, two cylinder surfaces are arranged along the axis, the surfaces of the two cylinder surfaces are uniformly charged with negative charges, and the generated balanced electric field force enables aerosol particles to be imprisoned on the central axis of the two cylinder surfaces and between the two charged cylindersThe gap facilitates the laser 11 injection. Two vertical electrode plates 9 and 10 are vertically and parallelly arranged, and a tiny small hole is formed in the center of the left electrode plate 9, so that aerosol particles can pass through the tiny small hole. The aerosol particles are decelerated by the electric field generated by the two vertical charged electrode plates, and the particle velocity is reduced to zero at the fixed trapping position.

As shown in fig. 4, two horizontal electrode plates in the aerosol particle trapping device generate a vertically downward electric field, so that the aerosol particles are subjected to an upward electric field force, thereby offsetting the influence of gravity; the vertical strip electrode plate generates a horizontal right electric field, so that aerosol particles are subjected to a horizontal left electric field force, and are decelerated.

As shown in fig. 3, at a position on the central axis between the two charged cylinders, the aerosol particles are subjected to a balanced electric force, which is formed by the mutual cancellation of electric forces of equal magnitude in two directions along the axis and electric forces of equal magnitude in several directions perpendicular to the axis. Therefore, when the aerosol particles are at the equilibrium position, the aerosol particles are in a stable equilibrium state by the electric field force directed to the equilibrium position in each direction, and even if the aerosol particles are slightly disturbed, the aerosol particles are returned to the equilibrium position by the recovery electric field force opposite to the deviation direction. Under such conditions, the aerosol particles are stably confined to a fixed position, and then LIBS laser can be used for irradiation, so that LIBS aerosol component detection and other related experiments can be carried out. As shown in FIG. 5, the present invention provides a whole flow chart of the detection method for aerosol, which can further perform LIBS detection experiment after the aerosol particle trapping device traps the aerosol particles at a fixed position.

The utility model discloses spectral detection system's application method as follows:

all instrument power is turned on and the vacuum pump is turned on first to create a vacuum environment in the vacuum chamber 15. And opening a switch of the aerosol particle trapping device, electrifying the horizontal electrified electrode plates 5 and 6, and uniformly electrifying the two electrified

cylinders

7 and 8 to form a trapping electric field. Aerosol particles are injected into the device through the conduit 1, the velocity sensor 2 detects their velocity and the time of emergence, and the controller 13 controls the electron guns 3, 4 to emit electrons as the particles pass by to charge the aerosol particles negatively. After aerosol particles enter the horizontal electrode plates 5 and 6, the aerosol particles are stressed in a balanced manner and move at a constant speed. After the particles enter the vertical charged electrode plates 9 and 10, the controller controls the vertical charged electrode plates to be charged for a short time, electric field force is generated to decelerate the particles, the speed is approximately zero when the particles reach a balance position, and the charging of the vertical charged electrode plates is removed at the moment. After the aerosol particles reach the equilibrium position, the aerosol particles are subjected to the trapping electric field generated by the two electrified cylinders, so that the aerosol particles are stably balanced and stay at the equilibrium position (the position on the axis at the center of the surfaces of the two cylinders). Thereafter, the LIBS system is operated to emit laser light to irradiate the sample, which is analyzed for composition by analyzing the spectral information emitted by the aerosol particles.

Claims

1. The aerosol single-particle trapping device is characterized by comprising a vacuum chamber, a guide pipe, an electron gun, a horizontal charged electrode plate, a charged cylinder and a vertical charged electrode plate, wherein the guide pipe, the electron gun, the horizontal charged electrode plate, the charged cylinder and the vertical charged electrode plate are positioned in the vacuum chamber; the two electrified cylinders are coaxially arranged; the two horizontal charged electrode plates are arranged in the two charged cylinders in parallel up and down; the two vertical charged electrode plates are vertical to the horizontal charged electrode plates and are respectively arranged in the two charged cylinders, and the vertical charged electrode plate at one end close to the guide pipe is provided with small holes for aerosol particles to pass through; the electron gun is arranged between the guide pipe and the horizontal strip electrode plate.

2. The aerosol single particle imprisoning device of claim 1, wherein the symmetry axes of said two horizontal charged electrode plates coincide with the central axis of the charged cylinder, the aerosol single particle exit trajectory exiting in the conduit; the small hole on the vertical charged electrode plate is positioned on the central axis of the charged cylinder.

3. The aerosol single particle confinement device of claim 2, wherein the aerosol single particle confinement device further comprises a controller; the controller is arranged outside the vacuum chamber and is respectively and electrically connected with the guide pipe, the electron gun, the horizontal charged electrode plate, the charged cylinder and the vertical charged electrode plate.

4. The aerosol single particle confinement device of claim 3, wherein the aerosol single particle confinement device further comprises a velocity sensor; the speed sensor is arranged at the outlet of the guide pipe and is connected with the controller.

5. A spectroscopic detection system comprising an aerosol single particle caging device as claimed in any one of claims 1 to 3 wherein said spectroscopic detection system further comprises a laser induced breakdown spectrometer; the laser induced breakdown spectrometer is arranged outside a vacuum chamber of the aerosol single-particle trapping device, and emergent laser is focused between the two electrified cylinders.

6. The spectroscopic detection system of claim 5 wherein the laser induced breakdown spectrometer comprises a laser, an electronic laser focuser, a spectroscopic detection head, an ICCD detector, a spectrometer; laser emitted by the laser passes through the electronic laser focusing device and then enters the vacuum chamber, aerosol particles emit a spectrum after being irradiated by a laser focus, and the aerosol particles are transmitted into the ICCD detector and the spectrometer through optical fibers after being detected by the spectrum detection head.

7. The spectroscopic detection system of claim 6 wherein a glass window is provided in the chamber wall of the vacuum chamber between the two charged cylinders for incidence of the laser light.

8. The spectroscopic detection system of claim 7 wherein the laser induced breakdown spectrometer further comprises a particle position detector; the particle position detector is arranged in a vacuum chamber of the aerosol single-particle trapping device and is connected with a spectrometer in a control mode.