97 results about "Absorption cell" patented technology

The invention discloses a frequency discrimination curve calibration system, method and device. A frequency locking technology is adopted, the output laser frequency of the seed laser is stably locked on an absorption peak of the atom / molecule absorption cell, and the problem of frequency drift of the seed laser is effectively solved. Meanwhile, two acousto-optic modulators are used for implementing accurate out-of-cavity passive frequency modulation on the seed laser, and the laser frequency is moved to a preset zero-speed frequency point of an optical frequency discriminator and a linear working area edge frequency point from an atom / molecule absorption peak position. In the calibration process, the telescope vertically points to the zenith, and atmospheric echoes with zero Doppler frequency shift are provided as reference. At the moment, the optical frequency discriminator measures and records the transmittance of a preset zero-speed frequency point in the center of the linear working area and the transmittance of an edge frequency point, and a new frequency discrimination curve can be derived based on the linear hypothesis of the frequency discrimination curve.

The invention relates to the technical field of laser light source measurement, and discloses a wide-range narrow-linewidth laser wavelength and linewidth measurement system, which can be flexibly matched with the center frequency of laser to be measured through the arrangement of a tunable laser, breaks through the strict limitation of the existing beat frequency method on the center frequency, effectively expands the measurement range, and improves the measurement accuracy. By combining the synergistic effect of the absorption cell and the locking loop, the system stability is improved, the measurement precision of narrow linewidth laser is guaranteed, the integration time can be flexibly adapted without tedious adjustment of a delay optical path or change of parameters of acquisition equipment through the cooperation of the optical modulator and the delay optical fiber, the problem of inconsistent measurement resolution under different integration time is avoided, and the measurement accuracy is improved. And the accuracy of short-time measurement is obviously improved. The system integrates wavelength and line width measurement functions, can measure line width, center wavelength and long-time frequency stability of to-be-measured laser, is reasonable in structural design, retains the advantage of high precision of a beat frequency method, overcomes the defects that an existing method is narrow in measurement range and inconvenient to adjust integral time, and improves the measurement accuracy of the to-be-measured laser. And the measurement requirements of wide-range and narrow-linewidth laser are met.

The invention relates to the technical field of gas sensing, and discloses a photoinduced thermoelastic spectrum gas concentration detection device and method based on an annular absorption cell, and the device comprises a light source system which is used for generating and outputting a wavelength-modulatable laser beam; the laser absorption system comprises an integrated annular absorption cell, an optical fiber collimator and an optical convergence lens, a laser window is arranged on the side wall of the integrated annular absorption cell, and after being input into the optical fiber collimator, a laser beam enters the integrated annular absorption cell through the laser window; after being reflected for multiple times, the light is emitted from the laser window and then enters the optical converging lens; the signal detection system is used for detecting the intensity of the emergent light focused by the optical converging lens and converting the intensity into an electric signal; and the data processing system is used for demodulating the electric signal generated by the signal detection system and inverting the concentration of the gas to be detected. The method corresponds to the device. According to the invention, the detection stability and the detection sensitivity are improved.

Laser absorption spectroscopy using multipass absorption based on multi-plane light conversion is a very sensitive chemical sensing technique to determine the molecular composition and concentration of a sample, especially a gas sample. To achieve a long optical path length while keeping the detector small, many trace gas sensors rely on multipass absorption cells in which the beam is reflected multiple times. The novel approach of the present invention consists in using multi-plane light conversion (MPLC) phase plates as reflectors in such multipass absorption cells.

The invention relates to a multi-component gas flux analysis system and a time delay determination method. The method comprises the following steps: controlling a first light source and a second light source to respectively emit first laser with a first wavelength and second laser with a second wavelength; the first laser is reflected between a first reflecting mirror and a second reflecting mirror of the open absorption cell for multiple times to obtain first emergent light, and the second laser is reflected between the first reflecting mirror and the second reflecting mirror for multiple times to obtain second emergent light; target gas passes between the first reflecting mirror and the second reflecting mirror, and the target gas comprises first gas and second gas which are different from each other; converting the first emergent light into a first electric signal; converting the second emergent light into a second electric signal; a first time delay is obtained based on the first electrical signal, a second time delay is obtained at least based on the second electrical signal, and the second time delay is corrected based on the first time delay. By adopting the method, the time calibration error in the vorticity flux calculation process can be reduced.

The invention relates to the technical field of gas sensing and optical detection, in particular to an annular multi-pass absorption cell and a detection method thereof.The annular multi-pass absorption cell comprises a reflecting mirror, the reflecting mirror is a cylinder with the two ends open, and a reflecting film is arranged on the inner wall of the reflecting mirror to form a continuous annular optical reflecting surface; the end cover assemblies are arranged at the openings in the two ends of the reflecting mirror, and a closed gas cavity is defined by the end cover assemblies and the reflecting mirror; an incident light hole and an emergent light hole are formed in the cylinder wall of the reflecting mirror and are respectively used for guiding a detection light beam to enter and exit from the gas chamber. The cylindrical reflector with two open ends is adopted, and an annular optical reflecting surface is formed on the inner wall of the cylindrical reflector, so that complex optical paths of discrete components in a traditional absorption cell are integrated in a single structure, the innovative design remarkably improves the system integration level, effectively compresses the size, can realize a longer absorption optical path in a limited space, and improves the absorption efficiency. The sensitivity of gas detection is greatly improved.

The invention belongs to the technical field of optical absorption cell parameter design, and particularly relates to an optical absorption cell design method and system based on PSO particle swarm optimization, and the method comprises the steps: S1, building a PSO model, defining each particle as an optical path, setting the number of particles and the maximum number of iterations, discretizing an absorption cell optical mirror surface into a movable grid, and defining the moving direction of the particles; s2, initializing the position and speed of a particle swarm based on the curvature radius, spacing and incident angle parameters of a reflector of the absorption cell; s3, performing optical simulation on each particle, and calculating a fitness value reflecting the optical length, the absorption cell volume and the light spot coverage based on a simulation result; updating an individual historical optimal path and a global historical optimal path; s3 is repeated after the speed and the position are updated and the state of each particle is adjusted; and S4, outputting the optical length, the volume and the lens number of the absorption cell corresponding to the final global optimal path. According to the method, efficient search can be carried out in the parameter space, and a globally optimal or approximately optimal solution is found.

The invention relates to the technical field of oil type gas monitoring, in particular to an oil type gas laser monitoring and early warning device and method, and the device comprises a processor control panel, a laser driver, a laser device group, a light path change-over switch, a diffusion type light absorption cell and a tuning fork detector; emergent laser with different gas spectrum absorption wavelengths is generated; switching each path of laser beam to a diffusion type absorption cell; respectively demodulating based on the acquired acquisition signals to obtain second harmonic signal voltages of optical signals of methane, ethane and hydrogen sulfide gas; inputting the second harmonic signal voltage of the optical signal absorbed by the to-be-detected gas into the residual neural network, identifying the methane and ethane gas overlapping spectrum, and outputting the methane and ethane gas concentration in the to-be-detected gas; and generating a multi-parameter early warning signal according to the methane and ethane gas concentrations and the hydrogen sulfide concentration. The light absorption detection can be accurately carried out on methane, ethane and hydrogen sulfide in the oil type gas, and the methane and ethane gas overlapping spectrum can be effectively identified.

The utility model provides a long-optical-path multi-reflection type oxygen concentration detection device which is used for solving the technical problems that an existing oxygen concentration detection device is low in identifiability and not high in sensitivity. The device comprises a laser transmit-receive optical system, a controller and a drive control unit, the controller is connected with the drive control unit, the drive control unit is connected with a laser of the laser transmit-receive optical system, a photoelectric detector of the laser transmit-receive optical system is connected with the controller, the laser transmit-receive optical system further comprises a gas absorption cell, and the gas absorption cell is connected with the controller. A long-optical-path multiple-reflection optical system is arranged in the gas absorption cell, the laser is arranged in front of a light input port of the long-optical-path multiple-reflection optical system, and the photoelectric detector is arranged on a light path of a light output port of the long-optical-path multiple-reflection optical system. The device has high resolution, and interference with other molecules can be avoided; the structure is simple and easy to realize; not only is the operation easy, but also the cost is effectively saved; the measurement process is very easy to realize and the practicability is very strong.

The invention provides a gas pressure control device for a direct absorption spectrum, which belongs to the technical field of direct absorption spectrums.The device comprises an absorption cell, and the gas inlet end and the gas outlet end of the absorption cell are respectively provided with a pressure sensor and an MFC which are connected with a control monitoring unit; the pressure sensors and the MFCs at the air inlet end and the air outlet end monitor the pressure intensity and the flow of the air inlet end and the air outlet end in real time and transmit the pressure intensity and the flow to the control monitoring unit, the control monitoring unit comprises an outer ring PID controller and an inner ring PID controller, and the pressure intensity of the air inlet end, the pressure intensity of the air outlet end and the set target pressure intensity are input into the outer ring PID controller to obtain outer ring output values; the outer ring output value is input into an inner ring PID controller to obtain an inner ring output value, the gas inlet end MFC adjusts the flow of the gas inlet end according to the inner ring output value, and the gas outlet end MFC adjusts the flow of the gas outlet end according to the inner ring output value. And double-closed-loop PID control regulation is adopted, so that the accuracy and stability of pressure control in the gas absorption cell are improved.

The invention discloses a TDLAS (Tunable Diode Laser Absorption Spectroscopy)-based gas concentration and temperature dual-parameter detection method and device, and the detection method comprises the following steps: 1, obtaining an optical signal passing through an absorption cell filled with gas to be detected, and converting the obtained optical signal into a digital signal to be detected; step 2, obtaining a fundamental frequency harmonic phase signal according to the digital signal to be measured and the two fundamental frequency reference signals; obtaining a second harmonic signal according to the digital signal to be measured and the two paths of frequency doubling reference signals; and 3, establishing an equation set of the fundamental frequency harmonic phase signal, the second harmonic signal and the gas concentration and temperature, and solving the equation set to obtain the gas concentration and temperature. According to the invention, the gas concentration and temperature signals are obtained through a simple method, the method can be used for replacing a lock-in amplifier, and the cost of a detection device and the system complexity can be effectively reduced.

1. Name of the product in this design: Gas Absorption Cell (Long Optical Path Multiple Reflections). 2. Purpose of this design: for gas detection and gas measurement. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: 3D view 1.

The present invention discloses a subwavelength ventilated asymmetric sound absorber, which is composed of one or more absorption cells. The absorption cell includes a metamaterial resonator and a backing impedance boundary. The backing impedance boundary includes a rear panel, a top panel, a bottom panel, a long plate and a short plate, which together form an L-shaped structure; a flow port is provided on the upper portion of the rear panel to facilitate airflow; the bottom of the metamaterial resonator is placed on the short plate of the backing impedance boundary, and a channel is left between it and the bottom plate of the backing impedance boundary; the back of the metamaterial resonator is fixedly connected to the side of the long plate of the backing impedance boundary, and a channel is left between it and the rear panel of the backing impedance boundary. The deep subwavelength absorber of the present invention can almost perfectly absorb the sound energy incident from the loss end and almost perfectly reflect the sound energy incident from the opposite end, has a good suppressive effect on broadband noise, and can achieve ventilation and heat dissipation functions while controlling noise.

The invention discloses a low-cost portable NDIR (Non-Dispersive Infra-Red) exhaled gas acetone detection device and an application method thereof, a constant current driving module is used for guaranteeing the stability of a base line, an infrared light source module is used for providing a stable intermediate infrared radiation source, an infrared light source is used for covering an acetone characteristic absorption wave band, and a gas absorption pool module is used for improving the detection sensitivity; the dual-channel infrared detection module is used for accurately capturing a light intensity attenuation signal of an acetone characteristic absorption wave band and realizing differential detection and anti-interference compensation, and the signal acquisition and amplification module is used for extracting an effective component related to the acetone concentration from a weak signal output by a pyroelectric detector; the upper computer processing module is used for performing differential operation and concentration inversion and calculating the concentration value of acetone in exhaled air; by fusing an MEMS infrared light source, a multiple reflection light path and a two-channel differential detection technology, high-sensitivity detection is realized, and a popular portable solution is provided for early screening of diabetes mellitus metabolic disorder and lung cancer.

This invention relates to a gas absorption cell for spectral parameter measurement, its installation method, and measurement method, belonging to the field of spectral parameter measurement technology. The gas absorption cell includes a gas absorption chamber and light transmission chambers symmetrically arranged on both sides of the absorption chamber. The light transmission chamber includes a containment chamber and a vacuum chamber, with the vacuum chamber located close to the gas absorption chamber. The gas absorption chamber and the vacuum chamber are separated by a third or fourth window, and the vacuum chamber and the containment chamber are separated by a spacer. The containment chamber houses the transmitting or receiving unit of the absorption spectrometer. The gas absorption chamber is filled with the target gas for spectral parameter measurement. The invention employs a five-segment structure consisting of the gas absorption chamber and the containment and vacuum chambers distributed on both sides of it, eliminating the need for a light guide device, resulting in a simple structure and convenient operation.

The utility model relates to the technical field of gas detection equipment, and provides a long-optical-path gas absorption cell which comprises a shell and a pipe body which form a closed gas cell with an annular section, a spliced reflector and a plane reflector which are respectively arranged on the inner sides of the two top ends of the gas cell, a light through hole is formed in the plane mirror, and a light inlet hole matched with the light through hole is formed in the shell; through the arrangement of the splicing reflecting mirror and the plane reflecting mirror, after the detection light enters the gas cell through the light through hole from the light inlet hole, the detection light is repeatedly reflected between the splicing reflecting mirror and the plane reflecting mirror, and finally the detection light is emitted out from the light inlet hole and the light through hole. The splicing reflecting mirror and the plane reflecting mirror are arranged, so that the laser can be repeatedly reflected between the splicing reflecting mirror and the plane reflecting mirror after being input; the laser optical path is prolonged, and the detection precision is improved. The gas cell is arranged between the pipe body and the shell, so that the volume of the gas cell is greatly reduced, the quantity demanded of gas filling the absorption cell is effectively reduced, and the sampling time is shortened.

The application relates to the technical field of gas spectrum detection, and discloses a CO2 gas concentration dual-wavelength detection system and method based on TDLAS-WMS, which comprises a main control upper computer, a signal generation and modulation module, a dual-channel laser module, an optical path module, a gas absorption cell, a photoelectric detection module and a signal acquisition and lock-in amplification module. The method comprises the following steps: initializing and loading parameters; generating a driving signal of superimposed scanning and modulation to drive a laser; extracting a second harmonic signal after the laser passes through the gas to be detected; realizing high signal-to-noise ratio concentration signal acquisition, automatically judging whether the current waveband is saturated or under-response, switching to another waveband, and realizing self-adaptive dynamic detection. Through dual-wavelength cooperation and self-adaptive switching, the technical problems of narrow dynamic range, easy saturation at high concentration, insufficient sensitivity at low concentration, and large error of a single-wavelength TDLAS system are solved, and wide-range, high-precision and continuous self-adaptive detection from low concentration to high concentration are realized.

This invention discloses an in-situ calibration system for an underwater dissolved gas sensor with an integrated self-calibration module. A 2004nm butterfly laser module emits laser light, and a Herriott absorption cell module allows the laser to be reflected multiple times by the detector gas, resulting in selective absorption of the laser at a characteristic wavelength to form an absorption spectrum. A synchronization control module handles power supply, communication, environmental parameter control, and calibration timing control, enabling synchronized switching between the system's measurement and calibration modes. A data processing module inverts the spectral data collected by the system to obtain dissolved gas concentration data. A self-calibration gas supply unit introduces standard gas into the Herriott absorption cell module when the calibration program starts. This invention integrates the self-calibration function with the sensor detection unit, effectively simplifying the operation and maintenance process of underwater gas monitoring, improving the long-term stability of the sensor, and making it suitable for in-situ dissolved gas monitoring in various underwater environments such as oceans, lakes, and reservoirs.

The invention relates to the technical field of spectrum detection, in particular to a multi-optical-path gas absorption cell which comprises a gas chamber, a first cavity mirror and a second cavity mirror, the first cavity mirror and the second cavity mirror are arranged at the two ends of the gas chamber, and each of the first cavity mirror and the second cavity mirror at least comprises a circular integration region, an inner annular reflection region and an outer annular reflection region, and the circular integration region is sleeved with the inner annular reflection region and the outer annular reflection region; the optical axis of the circular integration area of the first cavity mirror coincides with the optical axis of the circular integration area of the second cavity mirror. An included angle exists between the optical axes of the inner annular reflecting region of the first cavity mirror and the inner annular reflecting region of the second cavity mirror; the optical axis of the outer annular reflecting area of the first cavity mirror coincides with the optical axis of the outer annular reflecting area of the second cavity mirror. According to the invention, a heterotype mirror capable of realizing multi-optical-path detection is designed by combining a multi-pass cell and an off-axis integral cavity technology to replace a traditional cavity mirror, so that the problem that different optical paths cannot be compatible in a single gas chamber structure is solved, and multi-component trace gas absorption detection with a self-defined range can be realized through a single gas chamber.

This invention relates to a wide dynamic range laser spectroscopy gas concentration detection device and method. The device includes: a long-path absorption cell comprising two opposing first and second concave mirrors, wherein during operation, a first laser beam undergoes multiple reflections between the two concave mirrors to form a first absorption optical path; an optical resonant cavity sharing a gas cavity with the long-path absorption cell, comprising a second entrance window and a second exit window disposed at the geometric center region of the first and second concave mirrors, wherein the geometric center region is the non-spot region of the first laser beam; and a pair of high-reflectivity mirrors respectively disposed on the second entrance window and the second exit window, wherein during operation, the second laser beam undergoes multiple reflections between the two high-reflectivity mirrors to form a second absorption optical path; the second absorption optical path is not less than 100 times the first absorption optical path. This invention combines the advantages of both the long-path absorption cell and the optical resonant cavity, achieving full-range gas concentration measurement from ultra-low concentrations (ppb) to percentage concentrations through a single gas chamber.

The utility model relates to a compact infrared optical gas absorption cell and an infrared gas sensor thereof, the absorption cell comprises a cavity upper cover, a cavity lower cover, an infrared light source and a detector, the cavity upper cover is provided with a positioning boss, the cavity lower cover is provided with a positioning groove, and the infrared light source and the detector are arranged on the cavity lower cover. The cavity upper cover and the cavity lower cover are respectively positioned and matched through the positioning boss and the positioning groove, and the cavity upper cover and the cavity lower cover are combined and mounted to form an optical cavity by adopting a glue sealing mode; the center of the infrared light source and the center of the detector are located on the same circumference, so that infrared light emitted by the infrared light source is converged into the detector after being reflected for multiple times in the optical cavity. The compact infrared optical gas absorption cell disclosed by the utility model has the advantages of simple structure, convenience in assembly, small and exquisite appearance and long light path.

The utility model discloses an air purification device which comprises a main body with a hollow inner cavity, an air inlet and an air outlet which are formed in the two ends of the main body respectively, and an air inlet assembly, a fumigation assembly, an absorption assembly, a photocatalysis assembly and an air outlet assembly which are sequentially arranged in the main body in the air inlet direction. The fumigation assembly comprises a liquid storage bin used for storing a chlorine dioxide aqueous solution and an ultrasonic nebulizer arranged in the liquid storage bin and located below the liquid level. The absorption assembly comprises an absorption tank for storing water, an air inlet pipe with one end inserted into the absorption tank and an air outlet pipe with one end inserted into the absorption tank, and the other end of the air inlet pipe extends out of the absorption tank and is positioned above the liquid level in the liquid storage bin; the photocatalytic component comprises a photocatalytic treatment bin, an ultraviolet light source arranged in the photocatalytic treatment bin and a titanium dioxide nano coating; the other end of the gas outlet pipe extends out of the absorption cell and is positioned in the photocatalytic treatment bin. The air purification device disclosed by the utility model has a better overall purification effect on indoor air.

Present invention relates to a needle-free glucose measurement system which enable measurement of blood glucose level using concentration value of N2O molecule available in breath air, which comprises an electronic assembly (1.1) which stabilizes the temperature and flow of wavelength-adjustable laser light source (1.2) and controls wavelength, a laser-based sensor (1) which determines concentration values of N2O molecule by measuring the adsorption amount of detector (1.5) wherein beams coming from laser light source (1.2) are adsorbed by N2O molecules in the breath air in the adsorption cell (1.4), and a processor (2) which determine glucose values in the blood using the concentration data coming from laser-based sensor (1).

The invention relates to an etching end point detection method and system based on filtering scanning, and the method comprises the steps: irradiating infrared light emitted by a light source to an absorption cell, so as to output detection light after absorbing target gas; controlling the filter to perform wavelength scanning on the detection light, and identifying at least one characteristic wavelength point with an absorption peak; setting the fixed working frequency of the filter to allow the filter to pass through the detection light of the characteristic wavelength point; scanning the detection light of the characteristic wavelength point to obtain a first light intensity vector containing interference; calibrating a sidelobe response function matrix S of the filter; calculating the first light intensity vector according to the sidelobe response function matrix S to obtain a second light intensity vector for eliminating interference; and calculating the characteristic concentration c of the target gas according to the second light intensity vector, and judging an etching end point. According to the invention, the accuracy degree of etching end point judgment can be improved.

The invention relates to the technical field of noise light processing, in particular to a Herriott multi-pass cell-based noise optical isolator, which is used for filtering noise light contained in light rays of a light source and comprises a Herriott multi-pass cell, an absorption cell and a filtering medium, the Herriott multi-pass cell comprises a first concave mirror and a second concave mirror, a light inlet hole and a light outlet hole are formed in the edge positions of the first concave mirror and the second concave mirror respectively, the absorption cell is located between the first concave mirror and the second concave mirror, a filtering medium is contained in the absorption cell, and light of a light source enters the Herriott multi-pass cell through the light inlet hole; the light source light is repeatedly reflected between the first concave mirror and the second concave mirror and then leaves the Herriott multi-pass cell through the light outlet hole, and the light source light passes through the filter medium in the absorption cell during each reflection so as to filter noise light in the light source light. According to the invention, the optical path length of the light of the light source in the absorption cell is multiplied, the saturable absorption of small-signal noise light is realized, and the noise light isolation degree is effectively improved.

The utility model relates to the technical field of water quality monitoring, in particular to a water quality on-line long-optical-path measuring module, which comprises a signal transceiving unit main body, an absorption cell and a reflector mounting seat which are arranged on the same axis, two light through holes are arranged inside the signal transceiving unit main body, and the two light through holes are respectively a receiving end and a transmitting end. The transmitting end is in a T shape, the receiving end is in a left-narrow and right-wide shape, a spectroscope is installed at the junction of an upper light through hole, a reference receiving module opposite to the spectroscope is installed in a vertical end, an optical transmitting module is installed at a port of a transverse end, and a detection receiving module and a collimating lens are installed in a narrow opening in a lower light through hole. A total reflection prism is mounted on the inner side of the reflector mounting seat, and a heating wire is wound on the outer side of the absorption cell. The water quality on-line long-optical-path measurement module is provided with the reference receiver, the influence of light source energy fluctuation on a test result does not need to be considered, the system has no optical fiber attenuation, and the signal is stronger.

The application relates to the technical field of experimental instruments, in particular to an atomic absorption cover for experimental detection, which comprises an expansion cover and a wind guide pipe fixedly installed at the upper end of the expansion cover, the upper end of the wind guide pipe is provided with a gathering cover, the upper end of the gathering cover is fixedly provided with a wind guide fan, one side of the wind guide fan is provided with an exhaust pipe, and the inside of the wind guide pipe is fixedly provided with two air distribution plates; compared with the prior art, the atomic absorption cover can realize multi-mode selection during gas absorption by being provided with the expansion cover, an adjusting mechanism, a first air distribution plate, a second air distribution plate and the air distribution plates arranged in the inside of the wind guide pipe, can be arbitrarily switched for use in large-area air suction or channel air suction according to actual use requirements, and can solve the defects of a traditional fixed atomic absorption cover, can realize large-area air suction and prevent harmful gas from overflowing, and can realize strong air suction in a small-area range and improve air suction effect.

The invention discloses a TDLAS (Tunable Diode Laser Absorption Spectroscopy) gas concentration detection device and method based on digital phase demodulation, a DFB (Distributed Feedback) laser generates laser, the laser passes through an absorption cell filled with gas to be detected after passing through a collimator and is received by a photoelectric detector, and a data acquisition card converts an analog absorption signal into a digital signal to be detected; a data acquisition card is used for directly acquiring fundamental frequency sine and cosine reference signals which are generated by a signal generator and have the same frequency as a signal to be measured, the fundamental frequency sine and cosine reference signals are respectively multiplied by the signal to be measured and then subjected to low-pass filtering processing, and obtained mutually orthogonal signals are subjected to division operation and arc tangent operation processing to obtain fundamental frequency phase signals. And taking the vertical coordinate phases of the maximum value point and the minimum value point near the absorption peak as a phase difference, wherein the phase difference is used for measuring the gas concentration. The signal containing the concentration information is obtained through a simple method, the signal can be used for replacing a lock-in amplifier, and the cost of a detection device and the system complexity can be effectively reduced.

This invention relates to the field of spectral detection technology, specifically providing a multi-path gas absorption cell, comprising: a gas chamber, and a first cavity mirror and a second cavity mirror disposed at both ends of the gas chamber. Each of the first and second cavity mirrors includes at least: a circular integrating region, and an inner annular reflection region and an outer annular reflection region surrounding the circular integrating region; wherein the optical axes of the circular integrating regions of the first and second cavity mirrors coincide; the optical axes of the inner annular reflection regions of the first and second cavity mirrors are at an angle; and the optical axes of the outer annular reflection regions of the first and second cavity mirrors coincide. This invention, by combining multi-path cell and off-axis integrating cavity technology, designs a non-standard mirror that can realize multi-path detection, replacing traditional cavity mirrors and overcoming the problem of incompatibility between different optical paths in a single gas chamber structure. It enables the detection of trace gases with multiple components and custom ranges through a single gas chamber.

The present invention discloses a method and apparatus for synthesizing CF4 by activating SF6 using a two-stage dielectric barrier discharge (DBD) plasma. The present invention proposes a two-stage DBD plasma activation method for degrading SF6 and introducing CO2 gas to synthesize CF4. The first-stage DBD plasma reactor degrades SF6 molecules, breaking them down into fluorine atoms and other low-fluorine and sulfur small molecules. This step not only effectively degrades SF6 but also provides the necessary fluorine source for subsequent CF4 synthesis. The second-stage DBD plasma reactor uses CO2 as a carbon source to react with the low-fluorine and sulfur small molecules produced in the first reaction to generate CF4 gas. The CF4-containing mixed gas undergoes a first-stage condensation process to condense some of the fluorine-containing acidic waste gas into a liquid state. The remaining mixed gas then undergoes a second-stage condensation process to condense the CF4 gas into a liquid state and collect it, achieving efficient product separation and purification. Some acidic gases that do not participate in the reaction are treated in an alkaline absorption tank to reduce environmental harm.