A glow cathode plasma source having a light-transmitting gap

Abstract

The application discloses a glow cathode plasma source with a light transmission gap, belongs to the field of plasma discharge, and aims at solving the problem that the existing glow discharge equipment cannot realize optical monitoring. The glow cathode plasma source comprises a holding electrode, a quartz glass and a front end of an electron extraction electrode which is rotated and cut to have a hole for transporting plasma; the upper end of a cathode side wall surface is provided with a C-shaped gap, the upper end of a holding electrode side wall surface is provided with a first L-shaped gap, and the upper end of an electron extraction electrode side wall surface is provided with a second L-shaped gap; a working gas enters a chamber surrounded by the cathode through a gas inlet pipe; the cathode is provided with an external connecting post for applying a negative potential, the holding electrode is provided with an external connecting post for applying a positive high-voltage potential, and the working gas is broken down to generate plasma in a vacuum environment; and an optical monitor monitors the generated plasma through the C-shaped gap, the first L-shaped gap, the second L-shaped gap and the quartz glass. The application is used for a glow discharge plasma source.

Description

TECHNICAL FIELD

[0001] The present application relates to a glow cathode plasma source with a light transmission gap, belonging to the field of plasma discharge. BACKGROUND

[0002] The glow discharge plasma source has a very high application value in space propulsion, environmental management, material surface treatment, laser preparation and other aspects. The core reasons why the glow cathode plasma source can be used for the above applications are:

[0003] (1) The cathode surface of the glow discharge source emits a large number of electrons, which are used for neutralization of the plume in electric propulsion;

[0004] (2) The electrons collide with the raw gas to generate plasma, which contains active particles. The active particles and the pollutants react to convert them into harmless substances;

[0005] (3) The active particles and electrons interact with the treated objects, react, and achieve the purpose of etching;

[0006] (4) The glow discharge plasma generates high-energy excited state particles, and the collision transfer process of the excited state particles can be controlled to customize the exciter of a specific wavelength.

[0007] Therefore, the glow cathode plasma source has a wide range of applications in various industrial fields.

[0008] The existing plasma monitoring methods mainly include probe monitoring, mass spectrometry monitoring, laser monitoring and optical monitoring. Among them: the probe monitoring method is limited by its physical mechanism and cannot monitor the active particle composition generated by the plasma. The optical monitoring method can monitor the active particle composition, and combined with the relevant physical model, it can more quantitatively analyze the active particle concentration, which is undoubtedly the best choice for analyzing the physical mechanism of the glow discharge.

[0009] At present, the glow discharge device is generally a long cylindrical quartz glass tube, which can realize spatially resolved optical monitoring, but due to its size and material limitations, its engineering application value is limited. The glow discharge device generally used in engineering applications is generally a metal-coated structure, and the internal plasma light-emitting area of the discharge chamber cannot be monitored, and the discharge physical mechanism cannot be studied, and the glow cathode for engineering application cannot be optimized and designed. SUMMARY

[0010] The purpose of the present application is to solve the problem that the glow discharge device cannot be optically monitored, and a glow cathode plasma source with a light transmission gap is provided.

[0011] The glow cathode plasma source with a light transmission gap provided by the present application comprises a gas inlet pipe, a cathode, a trigger electrode, a quartz glass and an electron extraction electrode.

[0012] The cathode, the holding electrode, the quartz glass and the electron extraction electrode are in a cylindrical structure, and the cathode, the holding electrode, the quartz glass and the electron extraction electrode are in a concentric structure, and the cathode, the holding electrode and the electron extraction electrode are fixedly connected through ceramic bolts;

[0013] The rear wall surface of the cathode is provided with an opening, the opening is connected with the gas inlet pipe through a gas inlet flange, the front end of the cathode is sealingly connected with the rear end of the holding electrode, and the front end of the holding electrode is sealingly connected with the electron extraction electrode through the quartz glass;

[0014] The front end of the holding electrode, the quartz glass and the electron extraction electrode is provided with a hole for transporting plasma;

[0015] The upper end of the side wall surface of the cathode is provided with a "C"-shaped gap, the upper end of the side wall surface of the holding electrode is provided with a first "L"-shaped gap, and the upper end of the side wall surface of the electron extraction electrode is provided with a second "L"-shaped gap;

[0016] The lower section of the "C"-shaped gap, the lower section of the first "L"-shaped gap and the lower section of the second "L"-shaped gap are on the same section;

[0017] The working gas enters the chamber surrounded by the cathode through the gas inlet pipe;

[0018] The cathode is applied with a negative potential through an external terminal, the holding electrode is applied with a positive high-voltage potential through an external terminal, and the working gas is broken down to generate plasma in a vacuum environment;

[0019] The optical monitor monitors the generated plasma through the "C"-shaped gap, the first "L"-shaped gap, the second "L"-shaped gap and the quartz glass.

[0020] Preferably, the cathode and the gas inlet flange are rotationally fixedly connected through an annular ceramic gasket;

[0021] The cathode and the holding electrode are sealingly connected through a ceramic gasket, and the ceramic gasket is in a cylindrical boss structure;

[0022] The quartz glass is in a cylindrical structure, and is made of high-transmittance quartz glass which is transparent to ultraviolet rays.

[0023] Preferably, the length of the "C"-shaped gap is 5 mm, and the width is 2 mm.

[0024] Preferably, the length of the gap of the first "L"-shaped gap at the upper end of the side wall surface of the holding electrode is 4 mm, and the width is 2 mm, and the length of the gap of the first "L"-shaped gap at the front end of the holding electrode is 2 mm, and the width is 2 mm.

[0025] Preferably, the length of the slit on the side wall of the electron extraction electrode is 7mm, and the width is 2mm; the length of the slit on the front end of the electron extraction electrode is 8mm, and the width is 2mm.

[0026] Preferably, the diameter of the hole on the front end of the holding electrode for transporting plasma is 0.2mm; the diameter of the hole on the front end of the quartz glass for transporting plasma is 6mm; and the diameter of the hole on the front end of the electron extraction electrode for transporting plasma is 1mm.

[0027] Preferably, the electron extraction electrode is applied with a positive potential through an external terminal, and the positive potential applied on the electron extraction electrode is higher than the positive high-voltage potential applied on the holding electrode.

[0028] The present application provides another glow cathode plasma source with a light-transmitting gap, which comprises a cathode discharge cavity, an insulating support, an inner insulating ceramic, a holding electrode, an outer insulating ceramic, an electron extraction electrode and a ceramic shell.

[0029] The cathode discharge cavity, the holding electrode and the electron extraction electrode are coaxially fixed through the ceramic shell, the cathode discharge cavity and the holding electrode are fixed through the insulating support and the inner insulating ceramic, and the holding electrode and the electron extraction electrode are fixed through the outer insulating ceramic (25).

[0030] The front end of the holding electrode, the electron extraction electrode and the ceramic shell is cut to have a hole for transporting plasma.

[0031] The working gas enters the cathode discharge cavity through a gas inlet pipe.

[0032] The cathode discharge cavity is applied with a negative potential through an external terminal, the holding electrode is applied with a positive high-voltage potential through an external terminal, and the working gas is broken down to generate plasma in a vacuum environment.

[0033] An optical monitor monitors the generated plasma through the holes cut on the front end of the holding electrode and the electron extraction electrode.

[0034] Preferably, the diameter of the hole on the front end of the holding electrode for transporting plasma is 0.5mm; the diameter of the hole on the front end of the electron extraction electrode for transporting plasma is 2mm; and the diameter of the hole on the front end of the ceramic shell for transporting plasma is 10mm.

[0035] Preferably, the electron extraction electrode is applied with a positive potential through an external terminal, and the positive potential applied on the electron extraction electrode is higher than the positive high-voltage potential applied on the holding electrode.

[0036] The present application provides a glow cathode plasma source with a light-transmitting gap, which has the following advantages:

[0037] 1. Compared with the traditional thermal emission hollow cathode, the working medium has a wider range of use, is not limited by the emission body material, can use various gases for discharge, and has a wider application range.

[0038] 2. The optical monitoring device can detect the radiation photons through the light transmission gap or the light transmission hole, convert them into an electric signal, send them to an upper computer, and then quantitatively analyze the active ion composition by combining a related physical model, so that the glow cathode can be optimized and designed. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a structural schematic diagram of a glow cathode plasma source with a light transmission gap according to the first embodiment of the present application;

[0040] Figure 2 is a three-dimensional view of Figure 1 ;

[0041] Figure 3 is a structural schematic diagram of a glow cathode plasma source with a light transmission gap according to the second embodiment of the present application;

[0042] Figure 4 is a three-dimensional view of Figure 3 . DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0044] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0045] The present application will be further described below in combination with the drawings and specific embodiments, but is not limited by the present application.

[0046] Embodiment 1:

[0047] The present embodiment will be described below in combination with Figure 1 and Figure 2 . The present embodiment describes a glow cathode plasma source with a light transmission gap, which comprises a gas inlet pipe 1, a cathode 5, a holding electrode 7, a quartz glass 8, and an electron extraction electrode 9.

[0048] The cathode 5, contact electrode 7, quartz glass 8 and electron lead electrode 9 are all cylindrical structures, and the cathode 5, contact electrode 7, quartz glass 8 and electron lead electrode 9 are concentric structures. The cathode 5, contact electrode 7 and electron lead electrode 9 are fixed together by ceramic bolts 3.

[0049] The rear wall of the cathode 5 has an opening, which is connected to the air inlet pipe 1 through the air inlet flange 2. The front end of the cathode 5 is sealed to the rear end of the contact electrode 7, and the front end of the contact electrode 7 is sealed to the electronic lead electrode 9 through the quartz glass 8.

[0050] The front ends of the contact electrode 7, the quartz glass 8, and the electron lead electrode 9 are rotary-cut with holes for transporting plasma;

[0051] The upper end of the side wall of the cathode 5 has a "C" shaped slit 11, the upper end of the side wall of the contact electrode 7 has a first "L" shaped slit 12, and the upper end of the side wall of the electron lead electrode 9 has a second "L" shaped slit 13.

[0052] The lower cross-section of the "C"-shaped gap 11, the lower cross-section of the first "L"-shaped gap 12, and the lower cross-section of the second "L"-shaped gap 13 are on the same cross-section;

[0053] The working gas enters the chamber surrounded by the cathode 5 through the inlet pipe 1;

[0054] The cathode 5 is given a negative potential through an external terminal, and the contact electrode 7 is given a positive high voltage potential through an external terminal. The working gas is broken down in a vacuum environment to generate plasma.

[0055] The optical monitor monitors the generated plasma through the "C"-shaped slit 11, the first "L"-shaped slit 12, the second "L"-shaped slit 13 and the quartz glass 8.

[0056] Furthermore, the cathode 5 and the inlet flange 2 are rotatably fixed together by an annular ceramic gasket 4;

[0057] The cathode 5 and the contact electrode 7 are sealed together by a ceramic gasket 6, which is a cylindrical boss structure.

[0058] The quartz glass 8 has a cylindrical structure and is made of high-transmittance quartz glass that can transmit ultraviolet light.

[0059] In this embodiment, the annular ceramic gasket 4 is used to seal and insulate the cathode 5 and the inlet flange 2.

[0060] In this embodiment, the ceramic gasket 6 serves as a sealant and insulator.

[0061] Furthermore, the length of the "C"-shaped slit 11 is 5mm and the width is 2mm.

[0062] Further, the length of the slit of the first "L" shaped slit 12 at the upper end of the side wall of the holding electrode 7 is 4 mm, and the width is 2 mm. The length of the slit of the first "L" shaped slit 12 at the front end of the holding electrode 7 is 2 mm, and the width is 2 mm.

[0063] Further, the length of the slit of the second "L" shaped slit 13 at the upper end of the side wall of the electron emitting electrode 9 is 7 mm, and the width is 2 mm. The length of the slit of the second "L" shaped slit 13 at the front end of the electron emitting electrode 9 is 8 mm, and the width is 2 mm.

[0064] Further, the diameter of the hole for transporting plasma at the front end of the holding electrode 7 is 0.2 mm. The diameter of the hole for transporting plasma at the front end of the quartz glass 8 is 6 mm. The diameter of the hole for transporting plasma at the front end of the electron emitting electrode 9 is 1 mm.

[0065] Further, the positive potential is applied to the electron emitting electrode 9 through the external connecting post, and the positive potential applied to the electron emitting electrode 9 is higher than the positive high voltage potential applied to the holding electrode 7.

[0066] In the embodiment, the positive potential applied to the electron emitting electrode 9 is higher than the positive high voltage potential applied to the holding electrode 7, and the electrons can be emitted.

[0067] Example 2:

[0068] The embodiment will be described below Figure 3 and Figure 4 Another kind of glow cathode plasma source with light transmission slit is described in the embodiment, which comprises a cathode discharge cavity 21, an insulating support 22, an inner insulating ceramic 23, a holding electrode 7, an outer insulating ceramic 25, an electron emitting electrode 9, and a ceramic shell 24.

[0069] The cathode discharge cavity 21, the holding electrode 7, and the electron emitting electrode 9 are coaxially fixed through the ceramic shell 24. The holding electrode 7 and the electron emitting electrode 9 are fixed through the outer insulating ceramic 25.

[0070] The front end of the holding electrode 7, the electron emitting electrode 9, and the ceramic shell 24 is cut to have a hole for transporting plasma.

[0071] The working gas enters the cathode discharge cavity 21 through the gas inlet pipe.

[0072] The cathode discharge cavity 21 is applied with a negative potential through the external connecting post. The holding electrode 7 is applied with a positive high voltage potential through the external connecting post. The working gas is broken down to generate plasma in the vacuum environment.

[0073] The optical monitor monitors the plasma generated by the hole in the front end of the holding electrode 7 and the electron extraction electrode 9.

[0074] Further, the diameter of the hole in the front end of the holding electrode 7 for transporting the plasma is 0.5 mm; the diameter of the hole in the front end of the electron extraction electrode 9 for transporting the plasma is 2 mm; and the diameter of the hole in the front end of the ceramic shell 24 for transporting the plasma is 10 mm.

[0075] Still further, the electron extraction electrode 9 is applied with a positive potential through an external terminal, and the positive potential applied on the electron extraction electrode 9 is higher than the positive high-voltage potential applied on the holding electrode 7.

[0076] In the embodiment, the positive potential applied on the electron extraction electrode 9 is higher than the positive high-voltage potential applied on the holding electrode 7, so that the electrons can be extracted.

[0077] In the embodiment, the insulating support 22 is made of ceramic material. The insulating support 22, the inner insulating ceramic 23, the outer insulating ceramic 25 and the ceramic shell 24 are provided with three through holes with a diameter of 2 mm on the circular surface and at the same position for bolt fastening.

[0078] In the embodiment, the holding electrode 7 is made of stainless steel material, and the pin is provided with a through hole with a diameter of 2 mm for bolt fastening.

[0079] In the embodiment, the cathode discharge cavity 21, the holding electrode 7 and the electron extraction electrode 9 are fastened by the bolt holes on the insulating support 22, the inner insulating ceramic 23, the outer insulating ceramic 25 and the ceramic shell 24.

[0080] The present application provides a glow cathode plasma source with a light transmission gap. The working gas is injected into the ionization chamber (cathode 5 or cathode discharge cavity 21) through the gas inlet pipe, and the holding electrode 7 is applied with a positive voltage, and the ionization chamber (cathode 5 or cathode discharge cavity 21) is applied with a negative voltage. A part of the primary electrons in the chamber are ionized to generate plasma after obtaining the energy applied by the electric field of the holding electrode and the cathode, and the ions bombard the cathode under the acceleration of the electric field to continuously generate electrons, thereby maintaining the whole discharge process. In the process, the working gas is excited to a certain unstable excited state energy level under the action of the electrons, and the energy level radiates photons downward. The optical monitoring device can detect the radiated photons through the light transmission gap or the light transmission hole, convert the photons into an electric signal, and send the electric signal to the upper computer. Further, the active ion composition can be quantitatively analyzed by combining with a related physical model. For example, the optical monitoring method such as emission spectrum and laser-induced fluorescence spectrum can be used to quantitatively monitor the composition and concentration of the active particles in the glow discharge ionization chamber, and further analyze the action mechanism of the active particles and the target material.

[0081] While the application has been described with reference to particular embodiments thereof, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present application. It will be apparent to those skilled in the art that numerous modifications can be made within the scope of the present application as defined by the appended claims. It is intended that all such modification fall within the spirit and scope of the present application. It will be understood that the features described in connection with one embodiment can be used in connection with another embodiment.

Claims

1. A glow cathode plasma source having a light-transmitting gap, characterized in that, It comprises an air inlet pipe (1), a cathode (5), a holding electrode (7), a quartz glass (8) and an electron extraction electrode (9); The cathode (5), the holding electrode (7), the quartz glass (8) and the electron extraction electrode (9) are all in a cylindrical structure, and the cathode (5), the holding electrode (7), the quartz glass (8) and the electron extraction electrode (9) are in a concentric structure, and the cathode (5), the holding electrode (7) and the electron extraction electrode (9) are fixedly connected through ceramic bolts (3); The rear wall surface of the cathode (5) is provided with an opening, the opening is connected with the air inlet pipe (1) through an air inlet flange (2), the front end of the cathode (5) is sealingly connected with the rear end of the holding electrode (7), and the front end of the holding electrode (7) is sealingly connected with the electron extraction electrode (9) through the quartz glass (8); The front end of the holding electrode (7), the quartz glass (8) and the electron extraction electrode (9) is provided with a hole for transporting plasma; The upper end of the side wall surface of the cathode (5) is provided with a "C" shaped gap (11), the upper end of the side wall surface of the holding electrode (7) is provided with a first "L" shaped gap (12), and the upper end of the side wall surface of the electron extraction electrode (9) is provided with a second "L" shaped gap (13); The lower section of the "C" shaped gap (11), the lower section of the first "L" shaped gap (12) and the lower section of the second "L" shaped gap (13) are on the same section; The working gas enters the chamber surrounded by the cathode (5) through the air inlet pipe (1); The cathode (5) is applied with a negative potential through an external terminal, the holding electrode (7) is applied with a positive high voltage potential through an external terminal, and the working gas is broken down to generate plasma in a vacuum environment; The optical monitor monitors the generated plasma through the "C" shaped gap (11), the first "L" shaped gap (12), the second "L" shaped gap (13) and the quartz glass (8).

2. A glow cathode plasma source having a light-transmitting gap according to claim 1, characterized in that The cathode (5) and the air inlet flange (2) are rotatably fixed through an annular ceramic gasket (4); The cathode (5) and the holding electrode (7) are sealingly connected through a ceramic gasket (6), and the ceramic gasket (6) is in a cylindrical boss structure; The quartz glass (8) is in a cylindrical structure and is made of high-transmittance quartz glass which is transparent to ultraviolet rays.

3. A glow cathode plasma source having a light-transmitting gap according to claim 1 or 2, characterized in that The length of the "C" shaped gap (11) is 5 mm, and the width is 2 mm.

4. A glow cathode plasma source having a light-transmitting gap according to claim 1 or 2, characterized in that The length of the first "L" shaped gap (12) on the upper end of the side wall surface of the holding electrode (7) is 4 mm, and the width is 2 mm, and the length of the first "L" shaped gap (12) on the front end of the holding electrode (7) is 2 mm, and the width is 2 mm.

5. A glow cathode plasma source having a light-transmitting gap according to claim 1 or 2, characterized in that The length of the second "L" shaped gap (13) on the upper end of the side wall surface of the electron extraction electrode (9) is 7 mm, and the width is 2 mm, and the length of the second "L" shaped gap (13) on the front end of the electron extraction electrode (9) is 8 mm, and the width is 2 mm.

6. A glow cathode plasma source having a light-transmitting gap according to claim 1 or 2, characterized in that The diameter of the hole for transporting plasma on the front end of the holding electrode (7) is 0.2 mm, the diameter of the hole for transporting plasma on the front end of the quartz glass (8) is 6 mm, and the diameter of the hole for transporting plasma on the front end of the electron extraction electrode (9) is 1 mm.

7. A glow cathode plasma source having a light-transmissive gap as defined in claim 1, characterized in that The electron extraction electrode (9) is supplied with a positive potential via an external terminal, and the positive potential applied to the electron extraction electrode (9) is higher than the positive high voltage potential applied to the holding electrode (7).

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