Apparatus and method for generating plasma over a large pressure range and system and method for optical gas analysis / detection by means of such apparatus

Abstract

The invention relates to a device for generating plasma in a large pressure range. The device comprises a first plasma source (1) in a first discharge chamber (2) for generating a first plasma in a low pressure range, a second plasma source (3) in a second discharge chamber (4) for generating a second plasma in a high pressure range, a first coupling element (5) for coupling the device to a system in order to lead a gas out of the system, and a second coupling element (6) for coupling the device to an optical sensor (12). Here, the first discharge chamber (2) comprises a first optical connection to the second coupling element (6) with at least one optical lens (7, 8) and the second discharge chamber (4) comprises a second optical connection to the second coupling element (6) with at least one optical lens (8). The invention furthermore relates to a system for carrying out an optical gas analysis or gas detection and to a corresponding method for generating plasma and for operating the system.

Description

[0001] Related Applications On the same day as this application, a Swiss patent application entitled "Vakuumdurchführung, Elektrodenanordnung und Vorrichtung zur Erzeugung einerstillen Plasmaentladung" was filed by the same applicant as this patent application. The contents of the mentioned application are hereby incorporated in this patent application based on that reference. Technical Field

[0002] This invention relates to an apparatus and method for generating plasma. Furthermore, the invention relates to a system for optical gas analysis and / or gas detection using such an apparatus, such as a measuring device for determining gas composition or for detecting specific gases, and to a method for operating the system.

[0003] This invention belongs to the technical field of plasma generation, ionization, and the excitation of molecules and ions to generate plasma light, as well as the measurement and evaluation of information regarding the gas composition of the generated plasma. Background Technology

[0004] Optical emission spectroscopy (OES) is frequently used for quantitative and qualitative analysis of gas samples. This method is based on the fact that excited atoms emit electromagnetic radiation that characterizes chemical elements, thus providing information about the composition of the sample. For example, atoms are excited by converting the sample into a plasma state. Known instruments for performing optical emission spectroscopy utilize specific plasma sources, where plasma generation operates stably and sustainably over a defined pressure range. However, many applications involve very wide pressure ranges where gas composition plays a crucial role and therefore needs to be measured and monitored. This necessitates a large number of instruments for generating plasma, leading to high costs in electronics, software, space, energy, and overall cost. Consequently, systems that analyze gases over a wide pressure range require multiple measuring devices, such as spectrometers, and multiple flange ports.

[0005] Therefore, there is a need to develop instruments that enable, for example, a range from 10 -8 Plasma and its emitted light can be stably generated within a wide pressure range from 1500 Torr (high vacuum) to 1500 Torr (> normal pressure) or within said wide pressure range, with minimal space requirements and the lowest possible consumption of electronics, software, energy and cost. Summary of the Invention

[0006] The object of the present invention is to provide an apparatus for generating plasma over a wide pressure range (or over a wide pressure range), which can be connected to a facility (or system) in a space-saving manner, from which gases should be analyzed and / or detected, and which is less intensive and more cost-effective than known apparatus for generating plasma.

[0007] Furthermore, the objective of this invention is to describe a system for performing optical gas analysis or gas detection, the system comprising such advantageous means for generating plasma.

[0008] Furthermore, the objective of this invention is to provide a corresponding method for generating plasma over a large pressure range (or over a large pressure range).

[0009] Furthermore, the objective of this invention is to provide a corresponding method for performing optical gas analysis or gas detection.

[0010] According to the present invention, an apparatus for generating plasma over a wide pressure range, the apparatus comprising: - A first plasma source, wherein the first plasma source is arranged in a first discharge chamber and is configured to generate a first plasma in a low-pressure range, wherein the low-pressure range extends, in particular, to a high vacuum, i.e., for example, up to 10. -8 Entrust; - A second plasma source, wherein the second plasma source is arranged in a second discharge chamber and is configured to generate a second plasma in a high-pressure range, wherein the high-pressure range extends, in particular, above normal pressure, i.e., for example, to 1500 Torr. - A first coupling element, particularly having a flange, is used to couple the device to a system (particularly a gas source), wherein the coupling element is implemented to draw gas out of the system; - A second coupling element for coupling the device to an optical sensor, such as a photodiode or spectrometer, for performing optical gas analysis or gas detection (or pressure measurement). The first discharge chamber includes a first optical connection to a second coupling element having at least one optical lens, and the second discharge chamber includes a second optical connection to a second coupling element having at least one optical lens (wherein the optical lens may be a common optical lens of the first and second optical connections).

[0011] Therefore, the device according to the invention is characterized in that it is capable of generating at least two different forms of discharge, i.e., having two or more plasma sources integrated (together) in the (single) device. Furthermore, the device has only one (connection) flange by which it can be connected to a system with a gas to be analyzed, and the device also has only one coupling to a (single) optical sensor (such as a spectrometer) to, for example, from 10 -8 Optical gas analysis is performed across the entire pressure range up to 1500 Torr. The two discharge chambers of the (two) plasma sources can be arranged in parallel or series (sequentially), and the gas to be analyzed or detected can be delivered to each discharge chamber in parallel or guided from one discharge chamber to the next. Combinations of discharge chambers with parallel / side-by-side and series / sequential arrangements of plasma sources are also conceivable, the discharge chambers being fluidly connected to each other or hermetically decoupled.

[0012] Light emitted by the respective plasma is guided from the respective discharge chamber to a second coupling element (in front of the optical sensor) via an optical connection. Each optical connection here has an optical lens, and for example, two optical connections may also have a common optical lens. In addition to one or more optical lenses, the optical connection may, for example, include a suitable light guide (element), such as an optical fiber, tube, or rod.

[0013] In one implementation variant of the device, the low-pressure range and the high-pressure range together extend over a pressure range of at least 10 dekadens, particularly over 12 dekadens (e.g., in Torr).

[0014] In another implementation variant of the device, the low-pressure range and the high-pressure range overlap, particularly over a ten-fold range, for example, from 0.35 Torr to 3.5 Torr.

[0015] In another embodiment of the device, the first and second plasma sources are different plasma sources, for example, from the following groups, including glow discharge (cold cathode source), silent discharge (dielectric barrier discharge, DBD), high-frequency plasma source (RF plasma source), microwave plasma source (-> normal / atmospheric pressure plasma), and inductively coupled plasma (ICP source).

[0016] In another implementation variant of the device, the first discharge chamber is fluidly coupled to the second discharge chamber (especially when the same or nearly the same pressure exists in both discharge chambers).

[0017] In another implementation variation of the device, the first discharge chamber is decoupled from the second discharge chamber in an airtight manner.

[0018] In another embodiment of the device, gas can be delivered from the first coupling element to the first discharge chamber and from the first discharge chamber to the second discharge chamber.

[0019] In another embodiment of the device, gas can be separately delivered from the first coupling element to the first discharge chamber and the second discharge chamber.

[0020] In another embodiment of the device, an optical lens is arranged between the first discharge chamber and the second discharge chamber, and the optical lens is part of the first optical connection.

[0021] In another embodiment of the device, the second coupling element includes an optical lens that is part of the first and / or second optical connection.

[0022] In another implementation variation of the device, the second optical connection is part of the first optical connection, i.e., the two optical connections partially or segmentally overlap.

[0023] In another implementation variation, the device further includes a pressure sensor. The pressure sensor may be, for example, one of the following: -According to Pirani's thermal conductivity vacuum gauge (for approximately 10...) -3 (Measurement range from 1 to 1 tor). - According to Penning's ionization vacuum gauge with a cold cathode (for applications from approximately 10...) -7 Up to l0 -3 (Measurement range of Tor). - According to Bayard-Alpert's ionization vacuum meter with a thermionic cathode (for applications from approximately 10...) -12 Up to l0 -3 (Measurement range of Tor). - Capacitance diaphragm (vacuum) gauge, CDG; for use from approximately 10 -5 Up to l0 3 (Measurement range of Tor).

[0024] To cover, for example, from l0 -8With a wide pressure range of up to 1500 Torr, the device can also be equipped with multiple pressure sensors.

[0025] In another implementation variant, the device further includes a control device configured to control the first and / or second plasma source based on a pressure (or multiple pressures) determined by means of a pressure sensor (or multiple pressure sensors), specifically to turn the first and / or second plasma source on or off.

[0026] In another embodiment of the device, the first and second discharge chambers are implemented as cylindrical and arranged coaxially in series (on a common cylindrical axis), wherein a first coupling element is arranged in the first discharge chamber and a second coupling element is arranged in the second discharge chamber, wherein the first plasma source is in particular a glow discharge source (cold cathode source), and wherein the second plasma source is in particular a silent discharge source (for dielectric barrier discharge).

[0027] In another embodiment of the device, the anode of the first plasma source is encapsulated in glass in a feedthrough through an optical lens in a vacuum-sealed manner, and in particular, is also encapsulated in glass in a feedthrough through an optical lens arranged between the first discharge chamber and the second discharge chamber, and the two feedthroughs are arranged centrally in the two optical lenses, and the anode (on the common cylindrical axis of the two discharge chambers) extends coaxially through the second discharge chamber into the first discharge chamber.

[0028] In another embodiment of the device, the second plasma source has a high-voltage electrode and a ground electrode, wherein the high-voltage electrode is embedded in a dielectric that forms at least a portion of the inner wall of the second discharge chamber, and the ground electrode is arranged concentrically with the high-voltage electrode within the second discharge chamber and along the inner wall at a distance of less than 1 mm from the high-voltage electrode, particularly between 0.05 mm and 0.5 mm, particularly on a hollow cylinder made of, for example, ceramic. A gap exists between the inner wall and the ground electrode, in which an AC voltage, for example, in the range of ±1 to ±10 kV and a frequency in the range of 1 to 10 kHz, is applied between the high-voltage electrode and the ground electrode, forming a discharge region containing plasma (i.e., the second plasma). For example, the voltage curve can change from -5 kV to +5 kV and back again over the period of the AC voltage, i.e., 10 kV can be applied. ppThe voltage (peek-to-peek) is calculated from peak to peak. The voltage curve can, for example, correspond to a sine curve. Rectangular voltages are also possible. It is advantageous to change the voltage from positive to negative relative to ground potential. In this way, a significantly more stable plasma is obtained compared, for example, by varying the voltage between zero (GND) and a positive voltage or between zero (GND) and a negative voltage. For example, both the high-voltage electrode and the ground electrode can be constructed as thin-walled hollow cylinders. These two electrodes can also be segmented, i.e., constructed from conductive strips sequentially on the cylindrical surface.

[0029] In another embodiment of the device, the high-voltage electrode can be connected to ground (e.g., switchable / controlled ground) to operate the first plasma source and can be connected to a high-voltage AC power supply (e.g., switchable / controlled ground) to operate the second plasma source, and / or the anode can be connected to a high-voltage DC power supply (e.g., 3.3 kV DC voltage) (e.g., switchable or controlled ground) to operate the first plasma source and can be connected to ground (e.g., switchable / controlled ground) to operate the second plasma source.

[0030] In another embodiment of the device, the coaxial arrangement of the anode (especially) within the first discharge chamber (where the discharge chamber serves as the cathode) and the radial arrangement of the high-voltage electrode and the ground electrode (at the inner wall of the second discharge chamber) result in a first plasma generated by the first plasma source forming a cylindrical axis at the first discharge chamber and a first light emitted by the first plasma propagating axially toward the second coupling element, and a second plasma generated by the second plasma source forming a cylindrical axis at the inner wall of the second discharge chamber and a second light emitted by the second plasma propagating toward the second coupling element, especially inclined to the cylindrical axis of the second discharge chamber, such that the first light and the second light are incident on the optical lens in the second coupling element from different directions.

[0031] In another implementation variation of the device, the anode is made of molybdenum.

[0032] In another embodiment of the device, the first discharge chamber is made of titanium.

[0033] In another implementation variation of the device, the high-voltage electrode is made of platinum.

[0034] In another embodiment of the device, the dielectric is made of sapphire (Al2O3).

[0035] In another implementation variation of the device, the grounding electrode is made of molybdenum.

[0036] In another embodiment of the device, the optical lens or the optical lenses are made of sapphire (Al2O3).

[0037] According to another aspect of the invention, a system for performing optical gas analysis or gas detection (or pressure measurement) includes: -A device for generating plasma according to any one of the above-described embodiments; - A gas source, wherein the device for generating plasma is coupled to the gas source using a first coupling element, in particular using a flange; - An optical sensor, such as a photodiode or spectrometer, is used for optical gas analysis or gas detection (or pressure measurement), wherein a device for generating plasma is coupled to the optical sensor using a second coupling element.

[0038] According to another aspect of the present invention, a method for generating plasma over a wide pressure range by means of a device for generating plasma according to any of the embodiments described above includes the following steps: - Gas is delivered from the system to a first discharge chamber having a first plasma source and / or a second discharge chamber having a second plasma source via a first coupling element; - A first plasma is generated in a first discharge chamber by the first plasma source in a low-pressure range, wherein the low-pressure range extends particularly to a high vacuum, i.e., for example, to 10. -8 Torr, and / or through the second plasma source in the second discharge chamber, a second plasma is generated in a high-pressure range, wherein the high-pressure range extends in particular above normal pressure, i.e., for example, to 1500 Torr; -Guide the light emitted by the first plasma from the first discharge chamber via a first optical connection having at least one optical lens and / or guide the light emitted by the second plasma from the second discharge chamber via a second optical connection having at least one optical lens to a second coupling element for coupling the device to an optical sensor, such as a photodiode or a spectrometer; - At least a portion of the light emitted by the first and / or second plasma is coupled out via the second coupling element.

[0039] In one embodiment of the method, the second plasma source is a silent power source having a high-voltage electrode and a ground electrode, wherein an AC voltage having, for example, a voltage in the range of ±1 to ±10 kV and a frequency in the range of 1 to 10 kHz is applied between the high-voltage electrode and the ground electrode to generate the second plasma.

[0040] In another implementation variation of the method, the first and / or second plasma sources are manipulated according to the pressure determined by means of a pressure sensor, in particular turning the first and / or second plasma sources on or off.

[0041] In another embodiment of the method, in a pressure range where the low-pressure range and the high-pressure range overlap, for example in a pressure range of 0.35 Torr to 3.5 Torr, the first and second plasma sources simultaneously generate the first and second plasmas.

[0042] According to another aspect of the invention, a method for performing optical gas analysis or gas detection (or pressure measurement) includes performing the steps of any of the embodiments described above for generating plasma, and further includes the following steps: - The coupled output light is transmitted to an optical sensor, such as a photodiode or spectrometer; - Determine the gas or gas composition or detect a specific gas or gas composition (or determine the gas pressure) based on the coupled output light, especially the intensity and / or spectral distribution of the coupled output light.

[0043] If, within a pressure range where the low and high pressure ranges overlap—for example, between 0.35 Torr and 3.5 Torr—first and second plasma sources simultaneously generate first and second plasmas, this results in increased sensitivity in optical gas analysis or gas detection due to the higher (e.g., double) intensity of the light from the two plasmas. This is helpful, for example, for trace gas detection. Such simultaneous plasma generation by first and second plasma sources can also be helpful in identifying or determining partial components (partial pressure / concentration) of trace gases, since the fractionation of the gas by the two plasmas is different. Furthermore, it is possible to correct the optical analysis results of the second (or first) plasma using the results of optical analysis of the first (or second) plasma, or to use one to calibrate the other.

[0044] It should be noted that combinations of the above-described implementation variations are possible, and such combinations lead to more specific implementation variations of the present invention. Attached Figure Description

[0045] The non-limiting embodiments of the present invention are described in more detail below with reference to the figures. Wherein: Figure 1 A schematic diagram illustrating an embodiment of a device according to the present invention for generating plasma over a wide pressure range; Figure 2 A longitudinal sectional view is shown of an embodiment of a device according to the invention for generating plasma over a wide pressure range, with dimensional descriptions. Figure 3 The diagram shows the passage of the drawn plasma region according to... Figure 2 Alternative illustrations of the longitudinal sectional view of the embodiment. Figure 4This illustrates one variant of the device; and Figure 5 Another variation of the device is shown.

[0046] In the figure, the same reference numerals represent the same elements. Detailed Implementation

[0047] Figure 1 An embodiment of an apparatus for generating plasma over a wide pressure range according to the present invention is illustrated schematically. The apparatus includes a first plasma source 1, such as a glow discharge power source (GD, cold cathode source), arranged in a first discharge chamber 2, and a second plasma source 3, such as a silent discharge power source (DBD source), arranged in a second discharge chamber 4, wherein the two discharge chambers 2 and 4 are arranged sequentially (in series) adjacent to each other. Furthermore, the apparatus includes a first coupling element 5, for example having a flange, for coupling the apparatus to a system (not shown) containing gas. Gas is introduced from the system into the first discharge chamber 2 via the coupling element 5. Gas can flow from the first discharge chamber 2 into the second discharge chamber 4. For this purpose, for example, a plurality of (e.g., 6 to 12) vents, each having a diameter of at least 1 mm, are located between the two discharge chambers 2 and 4. The apparatus further includes a second coupling element 6 for coupling the apparatus to an optical sensor, such as a photodiode or spectrometer, for optical gas analysis or gas detection (or even for pressure measurement).

[0048] The first plasma source 1 is suitable for, for example, from 10 -8 Plasma is generated in a low-pressure range of approximately 3.5 Torr, and a second plasma source 2 is suitable for generating plasma in a high-pressure range, for example, from approximately 0.35 Torr to 1500 Torr. Therefore, depending on the gas pressure, the first (in low pressure -> high vacuum) or the second (in atmospheric pressure) plasma source 1, 3 will ignite the gas and thereby generate the first or second plasma 14, 15, which emit different light depending on the type or composition of the gas. In the pressure overlap region of the two plasma sources 1, 3, for example from 0.35 Torr to 3.5 Torr, the two plasma sources 1, 3 can also be activated simultaneously, thereby simultaneously generating the first and second plasmas 14, 15. This parallel operation of the two plasma sources 1, 3 is possible, especially due to the low power of the two discharges.

[0049] Light emitted by the first plasma 14 in the first discharge chamber 2 is guided through an optical lens 7 located between the two discharge chambers 2 and 4. The light is then guided through the second discharge chamber 4 and through a second optical lens 8 located in the second coupling element 6 to reach an optical sensor 12, by means of which optical gas analysis or gas detection (or pressure measurement) can be performed. The optical sensor 12 is sensitive in the wavelength range that can be transmitted through the two optical lenses 7 and 8. The optical sensor 12 can be a simple radiation sensor, such as a photodiode, but can also be a more complex optical sensor, such as a spectrometer.

[0050] The anode 9 of the first plasma source 1 is guided from the second coupling element 6 through the second optical lens 8 in the second coupling element 6, through the second discharge chamber 4, and through the first optical lens 7 located between the two discharge chambers 2 and 4 into the first discharge chamber 2. The anode 9 is encapsulated in glass, in particular, in a vacuum-sealed manner, within a feedthrough of the optical lens 8 in the second coupling element 6. The anode 9 can also be encapsulated in glass within a feedthrough of the optical lens 7 between the two discharge chambers 2 and 4. The feedthrough through the optical lens 7 can also be vacuum-sealed, which is not mandatory. The two feedthroughs are arranged, in particular, centrally within the two optical lenses 7 and 8, such that the anode 9 extends coaxially through the second discharge chamber 4 into the first discharge chamber 2. The cathode of the first plasma source 1 is located at the edge of the first discharge chamber 2, spaced apart from the anode 9. The inner wall of the first discharge chamber 2 can here form the cathode. The cathode is, for example, made of titanium. To generate a glow discharge of gas, a high DC voltage (HV DC), for example 3.3 kV, is applied between the anode 9 and the cathode. This high voltage accelerates electrons from the cathode material toward the anode 9. By applying an external magnetic field using a (permanent) magnet 13, electrons are directed along circular or helical paths. This increases the probability of collisions with atoms / molecules in the gas. These collisions result in the excitation or ionization of atoms / molecules. Ions migrate toward the cathode, thus generating an ion stream. Photons are generated, on the one hand, through the relaxation of excited atoms, molecules, and ions, and on the other hand, through the recombination of these ions. The emitted photons radiate throughout the space and, in particular, strike the first optical lens 7 between the two discharge chambers 2 and 4. Here, the arriving photons are refracted and guided to the second optical lens 8 in the second coupling element 6. The optical lenses 7 and 8 may be made of one or more materials, such as sapphire, and have an aspherical shape to counteract spherical aberration or chromatic aberration.

[0051] The optical wavelength range includes electromagnetic radiation with wavelengths from 100 nm to 1 mm, particularly the range of visible light, ultraviolet radiation, and infrared radiation.

[0052] Details regarding the second plasma source 3, i.e., the apparatus for generating silent plasma discharge, can be found in a Swiss patent application filed on the same day as this patent application by the same applicant, entitled "Vakuumdurchführung, Elektrodenanordnung und Vorrichtung zur Erzeugung einer stillenPlasmaentladung". The second plasma source 3 has a high-voltage electrode 10 and a ground electrode 11, wherein the high-voltage electrode 10 is embedded in a dielectric that forms at least a portion of the inner wall of the second discharge chamber 4. The ground electrode 11 is arranged concentrically with the high-voltage electrode 10 on the inner wall of the second discharge chamber 4, particularly on a hollow cylinder, for example, made of ceramic. The ground electrode 11 is located at a distance of less than 1 mm from the high-voltage electrode 10, wherein a gap exists between the inner wall and the ground electrode 11, in which a discharge region with (second) plasma 15 is formed when a high alternating current (HV AC) voltage is applied between the high-voltage electrode 10 and the ground electrode 11. The inventors have realized that, with this expansion of the gap, a dielectric barrier discharge (also known as dielectric barrier discharge, DBE) with high AC voltage in the range of ±1 to ±10 kV and frequency in the range of 1 to 10 kHz can be stably generated over a wide pressure range of about 0.35 Torr to 1500 Torr.

[0053] exist Figure 2 The diagram, along with the dimensional description, shows a longitudinal sectional view of an embodiment of a device according to the invention for generating plasma over a wide pressure range. In this variant embodiment, the first discharge chamber 2 and the second discharge chamber 4 are implemented as cylindrical and arranged coaxially in sequence (one might say, "connected in series"). Figure 1 As shown, the first coupling element 5 is arranged on the right side of the first discharge chamber 2, and the second coupling element 6 is arranged on the left side of the second discharge chamber 4. In this example, the total length of the device is only about 60 mm, and the total diameter is only about 25 mm. As this demonstrates, the present invention can achieve a very compact structure, which is therefore very space-saving.

[0054] Figure 3 Shown by according to Figure 2 Alternative illustrations of the longitudinal sectional view of the embodiment. Figure 3 The image also shows plasmas 14 and 15 in two discharge chambers 2 and 4, and schematically illustrates two optical connections L1 and L2. The areas in which plasmas 14 and 15 appear are bordered by dashed lines.

[0055] Figure 4 A longitudinal sectional view is shown through one embodiment, which is largely consistent with... Figure 1 The embodiment shown is consistent with that described above. Additionally, this variant includes at least one additional electrode 16, which is radially guided outside the high-voltage electrode 10 of the second plasma source and guided outward from the vacuum side insulated from the high-voltage electrode. This additional electrode is guided, for example, between a molten glass ring and a cylinder made of insulating material. Here, the cylinder made of insulating material may, for example, protrude beyond the molten glass ring on both sides to form a coherent support surface for the electrode. Multiple such additional electrodes are possible, wherein the electrodes can, for example, be constructed as strips having a longitudinal direction parallel to the longitudinal axis of the device. Multiple such additional electrodes may be distributed along an azimuth direction and arranged insulated from each other, such that most of these additional electrodes will be invisible or not visible in the longitudinal cross-sectional view. One or more such electrodes enable the connection of other sensors on the vacuum side or also enable alternative methods of connecting the anode and cathode of the first and second plasma sources as discussed so far.

[0056] Figure 5 Showing with Figure 4 Compared to the previous implementation, this one further includes an alternative wiring 17 to the anode of the first plasma source. The feedthrough from the outside to the plasma side is as follows: Figure 4 Implemented as discussed for the other electrodes 16, and in the case shown about the longitudinal axis of the device, 180 degrees opposite to the other electrodes 16 visible in the longitudinal section. Through drilling, alternative wiring 17 is guided into the first discharge chamber 2, contacting the center anode pin. Thus, it is possible to omit the step of... Figure 4 In a variant, an electrical connection is guided at the center via a second discharge chamber 4, and a feedthrough is established via a first optical lens 7 and a second optical lens 8. This has the effect that a larger component of the electromagnetic radiation from the first or second plasma reaches the outside. For example, the electrodes can be shielded with an insulating layer along their entire length. This has the advantage that undesirable open-circuit potentials that could affect charged particles are generally avoided in electronic / ion optics. For this purpose, for example, the glass ring located above the electrodes can be further axially expanded, or the individual printed conductors can be implemented using thin glass layers overlapping the respective printed conductors.

[0057] The advantage of this invention is that multiple plasma sources are integrated together in a single device, which further has only a single wiring for introducing the gas to be analyzed and only a single wiring for coupling the device to an optical sensor. Using the device according to the invention, plasma sources can be obtained from high vacuum (10... -8Stable plasma is generated over a pressure range exceeding approximately 12 decibels (in Torr) above normal pressure (> atmospheric pressure, e.g., 1500 Torr). According to the invention, it is further specified that the optimal plasma source is selected and controlled according to the pressure range by pressure measurements within the device.

[0058] List of reference numerals 1. First Plasma Source 2 First Discharge Chamber 3 Second Plasma Source 4 Second Discharge Chamber 5 First coupling element 6 Second coupling element 7. First optical lens (between the two discharge chambers) 8. Second optical lens (in the second coupling element) 9. Anode of the first plasma source 10 High-voltage electrode of the second plasma source 11 Grounding electrode of the second plasma source 12. Optical sensors (e.g., photodiodes or spectrometers) 13 (Permanent) Magnets 14 First Plasma 15 Second Plasma 16 Other electrodes 17 Alternative wiring for the anode of the first plasma source L1 First Optical Connection L2 Second Optical Connection.

Claims

1. An apparatus for generating plasma over a wide pressure range, the apparatus comprising: - A first plasma source (1), wherein the first plasma source (1) is arranged in a first discharge chamber (2) and is implemented to generate a first plasma (14) in a low-pressure range, wherein the low-pressure range extends to a high vacuum; - A second plasma source (3), wherein the second plasma source (3) is arranged in a second discharge chamber (4) and is implemented to generate a second plasma (15) in a high-pressure range, wherein the high-pressure range extends above normal pressure; - A first coupling element (5) for coupling the device to the system, wherein the coupling element (5) is implemented for drawing gas out of the system; - A second coupling element (6) is used to couple the device to an optical sensor for optical gas analysis or gas detection. The first discharge chamber (2) includes a first optical connection (L1) to the second coupling element (6) having at least one optical lens (7, 8) and the second discharge chamber (4) includes a second optical connection (L2) to the second coupling element (6) having at least one optical lens (8).

2. The device of claim 1, wherein the low-pressure range extends up to 10 -8 Torr, and the high-pressure range extends to 1500 Torr.

3. The device according to claim 1, wherein the first coupling element (5) has a flange.

4. The device according to claim 1, wherein the optical sensor is a photodiode or a spectrometer.

5. The device of claim 1, wherein the low-pressure range and the high-pressure range together extend over a pressure range of at least 10 times the range of 10.

6. The device of claim 1, wherein the low-pressure range and the high-pressure range together extend over a pressure range of 12 ten-fold ranges.

7. The device according to any one of claims 1 to 6, wherein the low-pressure range and the high-pressure range overlap.

8. The device according to any one of claims 1 to 6, wherein the low-pressure range and the high-pressure range overlap on a pressure range of ten times the range.

9. The device according to any one of claims 1 to 6, wherein the low-pressure range and the high-pressure range overlap in a pressure range from 0.35 Torr to 3.5 Torr.

10. The apparatus according to any one of claims 1 to 6, wherein the first and second plasma sources (1, 3) are different plasma sources.

11. The apparatus of claim 10, wherein the first and second plasma sources (1, 3) are respectively from the group consisting of a glow discharge power source, a silent discharge power source, a high-frequency plasma source, a microwave plasma source, and an inductively coupled plasma source.

12. The device according to any one of claims 1 to 6, wherein the first discharge chamber (2) is fluidly coupled to the second discharge chamber (4).

13. The device according to any one of claims 1 to 6, wherein gas can be delivered from the first coupling element (5) to the first discharge chamber (2) and from the first discharge chamber (2) to the second discharge chamber (4).

14. The device according to any one of claims 1 to 6, wherein an optical lens (7) is arranged between the first discharge chamber (2) and the second discharge chamber (4), the optical lens being part of the first optical connection (L1).

15. The device according to any one of claims 1 to 6, wherein the second coupling element (6) comprises an optical lens (8) which is part of the first and / or second optical connection (L1, L2).

16. The device according to any one of claims 1 to 6, wherein the second optical connection (L2) is a part of the first optical connection (L1).

17. The device according to any one of claims 1 to 6, wherein the device further comprises a pressure sensor.

18. The apparatus of claim 17, wherein the apparatus further comprises a control device configured to control the first and / or second plasma sources (1, 3) based on a pressure determined by means of the pressure sensor.

19. The apparatus of claim 17, wherein the apparatus further comprises a control device configured to switch on and / or off the first and / or second plasma sources (1, 3) based on a pressure determined by means of the pressure sensor.

20. The device according to any one of claims 1 to 6, wherein the first discharge chamber (2) and the second discharge chamber (4) are implemented as cylindrical and arranged coaxially in sequence, wherein the first coupling element (5) is arranged at the first discharge chamber (2) and the second coupling element (6) is arranged at the second discharge chamber (4).

21. The apparatus of claim 20, wherein the first plasma source (1) is a glow discharge power source, and wherein the second plasma source (3) is a silent discharge power source.

22. The device according to claim 20, wherein the anode (9) of the first plasma source (1) is encapsulated in a vacuum-sealed manner in a feedthrough of an optical lens (8) passing through the second coupling element (6), and is also encapsulated in a feedthrough of an optical lens (7) arranged between the first discharge chamber (2) and the second discharge chamber (4), and the two feedthroughs are centrally arranged in the two optical lenses (7, 8), and the anode (9) extends coaxially through the second discharge chamber (4) into the first discharge chamber (2).

23. The device according to claim 20, wherein the second plasma source (3) has a high-voltage electrode (10) and a ground electrode (11), wherein the high-voltage electrode (10) is embedded in a dielectric that forms at least a portion of the inner wall of the second discharge chamber (4), and the ground electrode (11) is arranged concentrically with the high-voltage electrode (10) within the second discharge chamber (4) and along the inner wall at a distance of less than 1 mm from the high-voltage electrode (10), wherein there is a gap between the inner wall and the ground electrode (11) in which an alternating voltage is applied between the high-voltage electrode (10) and the ground electrode (11), forming a discharge zone with plasma.

24. The device according to claim 23, wherein the grounding electrode (11) is concentric with the high-voltage electrode (10) in the second discharge chamber (4) and arranged along the inner wall at a distance between 0.05 mm and 0.5 mm from the high-voltage electrode (10).

25. The device according to claim 23, wherein the grounding electrode (11) and the high-voltage electrode (10) are arranged concentrically on a hollow cylinder.

26. The device according to claim 25, wherein the hollow cylinder is a hollow cylinder made of ceramic.

27. The device of claim 23, wherein the AC voltage has a voltage in the range of ±1 to ±10 kV and a frequency in the range of 1 to 10 kHz.

28. The device according to claim 22, wherein the second plasma source (3) has a high-voltage electrode (10) and a ground electrode (11), wherein the high-voltage electrode (10) is embedded in a dielectric that forms at least a portion of the inner wall of the second discharge chamber (4), and the ground electrode (11) is arranged concentrically with the high-voltage electrode (10) within the second discharge chamber (4) and along the inner wall at a distance of less than 1 mm from the high-voltage electrode (10), wherein there is a gap between the inner wall and the ground electrode (11) in which an alternating voltage is applied between the high-voltage electrode (10) and the ground electrode (11), forming a discharge zone with plasma.

29. The device according to claim 28, wherein the high-voltage electrode (10) is connectable to ground (GND) for operating the first plasma source (1) and is connectable to a high-voltage AC power supply for operating the second plasma source (3), and / or wherein the anode (9) is connectable to a high-voltage DC power supply for operating the first plasma source (1) and is connectable to ground (GND) for operating the second plasma source (3).

30. A system for performing optical gas analysis or gas detection, the system comprising: - An apparatus for generating plasma according to any one of claims 1 to 29; - A gas source, wherein the device for generating plasma is coupled to the gas source using a first coupling element; - An optical sensor for optical gas analysis or gas detection, wherein a device for generating plasma is coupled to the optical sensor using a second coupling element.

31. The system of claim 30, wherein the device for generating plasma is coupled to the gas source via a flange.

32. The system of claim 30, wherein the optical sensor is a photodiode or a spectrometer.

33. A method for generating plasma over a wide pressure range using the apparatus according to any one of claims 1 to 29, the method comprising the steps of: - Gas is delivered from the system to a first discharge chamber (2) having a first plasma source (1) and / or a second discharge chamber (4) having a second plasma source (3) via a first coupling element (5); - A first plasma (14) is generated in a low-pressure range in a first discharge chamber (2) by the first plasma source (1), wherein the low-pressure range extends to high vacuum, and / or a second plasma (15) is generated in a high-pressure range in a second discharge chamber (4) by the second plasma source (3), wherein the high-pressure range extends above normal pressure; - The light emitted by the first plasma (14) is directed from the first discharge chamber (2) via a first optical connection (L1) having at least one optical lens (7, 8) and / or the light emitted by the second plasma (15) is directed from the second discharge chamber (4) via a second optical connection (L2) having at least one optical lens (8) to a second coupling element (6) for coupling the device to an optical sensor. - At least a portion of the light emitted by the first and / or second plasmas (14, 15) is coupled out via the second coupling element (6).

34. The method of claim 33, wherein the low-pressure range extends to 10 -8 Torr, and the high-pressure range extends to 1500 Torr.

35. The method of claim 33, wherein the optical sensor is a photodiode or a spectrometer.

36. The method of claim 33, wherein the first and / or second plasma sources (1, 3) are manipulated according to a pressure determined by means of a pressure sensor.

37. The method of claim 36, wherein the first and / or second plasma sources (1, 3) are switched on or off based on a pressure determined by means of a pressure sensor.

38. The method of claim 36, wherein in the pressure range where the low pressure range and the high pressure range overlap, the first and second plasma sources (1, 3) simultaneously generate the first and second plasmas (14, 15).

39. The method of claim 36, wherein the first and second plasma sources (1, 3) simultaneously generate first and second plasmas (14, 15) within a pressure range of 0.35 Torr to 3.5 Torr.

40. A method for performing optical gas analysis or gas detection, the method comprising performing the steps of any one of claims 33 to 39, and further comprising the following steps: - Transmit the coupled output light to the optical sensor; - Determine the composition of a gas or gas based on the coupled output light, or detect the composition of a gas or gas, or determine the pressure of a gas.

41. The method of claim 40, wherein the optical sensor is a photodiode or a spectrometer.

42. The method of claim 40, wherein determining the gas or gas composition or detecting the gas or gas composition or determining the gas pressure based on the coupled output light comprises: The intensity and / or spectral distribution of the coupled output light are used to determine the gas or its components, or to detect the gas or its components, or to determine the gas pressure.

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