# US 12,014,900 B2 · Optical system for monitoring plasma reactions and reactors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,014,900 B2 - Document ID: US12014900B2 - Status: Granted - Kind: B2 - Application number: 18/045,813 - Filed: 2022-10-11 - Published: 2023-04-13 - Granted: 2024-06-18 - Earliest claimed: 2019-03-25 - Assignees: ReCarbon, Inc. - Applicants: ReCarbon, Inc. - Inventors: Curtis Peter Tom; Fei Xie; Wei Li; Stefan Andrew McClelland - Web page: https://patentgrep.com/patent/US12014900B2 ## CPC - B01J 19/088: {giving rise to electric discharges (for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00)} - H01J 37/32229: {Waveguides} - B01J 19/12: employing electromagnetic waves - C23C 16/511: using microwave discharges - G01J 1/0425: {using optical fibers} - G01J 1/0492: {using at least two different filters} - G01J 1/4228: {arrangements with two or more detectors, e.g. for sensitivity compensation} - G01J 1/429: {applied to measurement of ultraviolet light (using counting tubes G01T)} - G01J 5/0018: {Flames, plasma or welding} - H01J 37/32449: {Gas control, e.g. control of the gas flow} - H01J 37/32522: {Temperature} - H01J 37/32623: {Mechanical discharge control means} - H01J 37/32844: {Treating effluent gases} - H01J 37/32972: {Spectral analysis} - H05H 1/46: using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence) - F01N 2240/28: a plasma reactor - H01J 37/32192: {Microwave generated discharge (H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence)} - H01J 37/32513: {Sealing means, e.g. sealing between different parts of the vessel} - H01J 2237/1502: Mechanical adjustments - H05H 1/4622: {using waveguides} - Y02C 20/30: of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6] - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - H05H: PLASMA TECHNIQUE (apparatus or processes specially adapted for producing X-rays H05G2/00); PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG] ## Abstract The present invention provides a plasma generating system that includes: a waveguide; a plasma cavity coupled to the waveguide and configured to generate a plasma therewithin by use of microwave energy; a hollow cylinder protruding from a wall of the waveguide and having a bottom cap that has an aperture; a detection unit for receiving the light emitted by the plasma through the aperture and configured to measure intensities of the light in an ultraviolet (UV) range and an infrared (IR) range; and a controller for controlling the detection unit. ## Claims ### Claim 1 A plasma generating system, comprising: a plasma cavity for generating a plasma therewithin by use of microwave energy; a flow inlet being configured to introduce a gas into the plasma cavity, the gas to enter the plasma cavity in a direction that is not along a central axis of the plasma cavity, the flow inlet being at a first end of the plasma cavity and configured to generate a vortex flow within the plasma cavity using the gas, the flow inlet having a first opening, a second opening, and a gas passageway disposed therethrough from the first opening to the second opening, the gas passageway being curved to enhance a vorticity of the flow; a detection unit for measuring intensities of light emitted by the plasma cavity; and a controller for controlling the detection unit. ### Claim 2 (depends on 1) The plasma generating system as recited in claim 1, further comprising: a waveguide coupled to the plasma cavity; and a hollow cylinder protruding from a wall of the waveguide and having a bottom cap that includes an aperture, wherein the detection unit is arranged to receive the light through the aperture. ### Claim 3 (depends on 2) The plasma generating system as recited in claim 2, wherein the aperture is dimensioned to prevent leakage of the microwave energy therethrough while still allowing enough light through for detection. ### Claim 4 (depends on 1) The plasma generating system as recited in claim 1, wherein the detection unit includes: a sensor for converting light into an electrical signal; and a board having an electrical circuit, the sensor being mounted on the board, wherein the electrical circuit conditions the electrical signal and sends the electrical signal to the controller. ### Claim 5 (depends on 4) The plasma generating system as recited in claim 4, further comprising: a switchable bandpass filter disposed in front of the sensor and having one or more bandpass filters that each pass light in a wavelength range. ### Claim 6 (depends on 1) The plasma generating system as recited in claim 1, further comprising: a lens for collecting the light onto the detection unit. ### Claim 7 (depends on 1) The plasma generating system as recited in claim 1, wherein the detection unit includes: a first sensor for measuring intensity of the light in an ultraviolet (UV) range; and a second sensor for measuring intensity of the light in an infrared (IR) range. ### Claim 8 (depends on 7) The plasma generating system as recited in claim 7, further comprising: a first bandpass filter disposed in front of the first sensor and configured to pass the light in the UV range; and a second bandpass filter disposed in front of the second sensor and configured to pass the light in the IR range. ### Claim 9 (depends on 1) The plasma generating system as recited in claim 1, further comprising: a waveguide coupled to the plasma cavity; and an optical fiber installed in the waveguide and having one end for receiving the light and an other end coupled to the detection unit. ### Claim 10 (depends on 1) The plasma generating system as recited in claim 1, further comprising: a waveguide for transmitting the microwave energy therethrough; an inner wall disposed within the waveguide to define the plasma cavity; an adaptor mounted on the waveguide and configured to introduce a gas into the plasma cavity and generate a vortex flow within the plasma cavity using the gas, the adaptor having a through hole through which a gas processed by the plasma exits the plasma cavity; and an optical fiber installed in the adaptor and having one end for receiving the light and an other end coupled to the detection unit. ### Claim 11 (depends on 1) The plasma generating system as recited in claim 1, further comprising: a waveguide for transmitting the microwave energy therethrough; the flow inlet being a forward flow inlet mounted on the waveguide and configured to introduce the gas into the plasma cavity and to generate a vortex flow within the plasma cavity using the gas; and an optical fiber installed in the forward flow inlet and having one end for receiving the light and an other end coupled to the detection unit. ### Claim 12 (depends on 1) The plasma generating system as recited in claim 1, the gas passageway having a geometry to impart a spiral motion to the flow as the flow enters the plasma cavity via the gas passageway. ### Claim 13 (depends on 1) The plasma generating system as recited in claim 1, further comprising a plasma stabilizer protruding into the plasma cavity and configured to contribute to the vortex flow within the plasma cavity. ### Claim 14 (depends on 1) The plasma generating system as recited in claim 1, the gas passageway being configured for tangential gas injection with respect to a direction of flow at a gas outlet. ### Claim 15 (depends on 1) The plasma generating system as recited in claim 1, the gas passageway being shaped or positioned to introduce the gas into the plasma cavity in a direction other than along a central axis of the plasma cavity. ### Claim 16 (depends on 1) The plasma generating system as recited in claim 1, wherein the detection unit includes: a sensor to generate an electrical signal based on sensed light; and an electrical circuit to condition the electrical signal generated by the sensor and to send the conditioned electrical signal to the controller. ### Claim 17 (depends on 1) The plasma generating system as recited in claim 1, wherein the controller is configured to determine at least one of: a possible input gas issue or damage to the plasma cavity based on a combination of both an ultraviolet (UV) range and an infrared (IR) range emissions of varying amplitudes; a possible deposition on a surface of the plasma cavity based on the measured intensity of light emitted by the plasma in the IR range; or a diminution of IR intensity and a presence of UV that is indicative of plasma stability.