WO2021063003A1

WO2021063003A1 - Gas spectrum analyzer

Info

Publication number: WO2021063003A1
Application number: PCT/CN2020/091143
Authority: WO
Inventors: 刘鹏; 张真; 谭崇刚; 钱月康
Original assignee: 南京云创大数据科技股份有限公司
Priority date: 2019-09-30
Filing date: 2020-05-20
Publication date: 2021-04-08
Also published as: CN110632013A

Abstract

A gas spectrum analyzer, comprising an ultraviolet light source (1), a lens group (2), an ultraviolet multiple reflection cell (3), an automatic calibration cell (4), an ultraviolet optical fiber (5), an optical fiber spectrometer (6) and a transmission control unit (7). The ultraviolet light source (1), the lens group (2), the ultraviolet multiple reflection cell (3) and the automatic calibration cell (4) constitute a unique ultraviolet spectrum detection structure; the ultraviolet light source (1) sequentially undergoes beam expansion, multiple reflection, calibration, transmission and optical fiber spectrum analysis by the lens group (2), the ultraviolet multiple reflection cell (3), the automatic calibration cell (4), the ultraviolet optical fiber (5) and the optical fiber spectrometer (6) so as to obtain a gas spectrum analysis result; and the transmission control unit (7) communicates with the optical fiber spectrometer to collect, analyze, process and upload gas data. The use of the small ultraviolet multiple reflection cell (3) greatly expands the measurement optical path, achieves the miniaturization of a device while ensuring the high precision of a measurement result, and simultaneously achieves linear measurement within the optical path range so that the measurement result is more representative and more reliable. Employing a multi-component DOAS filtering algorithm solves the problems of an ultraviolet waveband environment and multi-component cross-interference, and improves monitoring precision and accuracy.

Description

A gas spectrum analyzer

Technical field

The invention belongs to the technical field of spectrum analysis and gas monitoring, and specifically relates to a gas spectrum analyzer.

Background technique

With the rapid development of industry and transportation, especially the large-scale use of coal and petroleum, a large number of harmful substances are produced, such as smoke, sulfur dioxide, nitrogen oxides, carbon monoxide, and hydrocarbons. These harmful substances are continuously discharged into the atmosphere. When their content exceeds the limit allowed by the environment and lasts for a certain period of time, they will change the normal composition of the atmosphere, especially the air, and destroy the natural physical, chemical and ecological balance system. Thereby endangering people's life, work and health, damaging natural resources, property, utensils, etc., this situation is called air pollution or air pollution. Atmospheric environment is a necessary condition for human survival and development. Protecting and improving the quality of the atmospheric environment is of great significance for promoting the development of human society and economy and safeguarding human health. The protection and supervision of the atmospheric environment depends on the atmospheric environment. monitor.

Commonly used on-site monitoring methods for pollution sources can be divided into optical methods and non-optical methods. Optical methods include ultraviolet, infrared photometry and spectroscopy. Non-optical methods mainly include electrochemical methods, chromatography, and mass spectrometry. For on-site chemical industry park instruments, the electrochemical gas sensor is small in size and can be applied to portable on-site measurement, but its disadvantage is that it needs to be equipped with a corresponding gas sensor for each gas. It can only perform point measurement at the current location and has a short life. It is easy to be "poisoned" and cause measurement failure; chromatography has high-efficiency separation of multi-component compounds, and mass spectrometry has superior structure identification and sensitive and accurate quantification capabilities, but its time resolution is low, cost is high, and the operation is complicated, so it is not suitable Real-time measurement in portable on-site. Most of the domestically developed chemical parks use electrochemical methods for on-site monitoring. Compared with traditional electrochemical and gas chromatography methods, optical methods have the advantages of fast, simple and accurate. Among them, ultraviolet spectroscopy can also measure multiple gas components at the same time. , The advantages of small size of the detector are the current development trend. However, the existing optical monitoring instruments are large in size or low in accuracy, and are not suitable for the needs of chemical parks that require supervisory monitoring. There is no miniaturized high-precision online gas monitoring product based on ultraviolet absorption spectroscopy technology.

Differential absorption spectroscopy (DOAS) mainly uses the characteristic absorption of absorbing molecules in the ultraviolet to visible range to study the trace gas composition of the atmosphere. Differential absorption spectroscopy technology uses the narrow-band absorption characteristics of gas molecules in the air to identify gas components and derives the gas concentration based on the narrow-band absorption intensity. Therefore, the differential absorption spectroscopy method has some advantages that traditional detection methods cannot match.

Summary of the invention

The technical problem to be solved by the present invention is to provide a gas spectrum analyzer in view of the above-mentioned shortcomings of the prior art, which solves the problem of incompatibility between the volume and accuracy of the existing optical detector, and realizes the small size, high precision and convenient installation. , Simple on-site real-time measurement.

In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

A gas spectrum analyzer, including an ultraviolet light source, a lens group, a small ultraviolet multiple reflection pool, an automatic calibration pool, an ultraviolet optical fiber, an optical fiber spectrometer, and a transmission control unit;

The ultraviolet light source, lens group, small ultraviolet reflection cell and automatic calibration cell constitute a unique ultraviolet spectrum detection structure;

The ultraviolet light source passes through a lens group, a small ultraviolet multiple reflection cell, an automatic calibration cell, an ultraviolet optical fiber, and an optical fiber spectrometer in sequence;

The ultraviolet light source sequentially passes through the lens group, the small ultraviolet multiple reflection pool, the automatic calibration pool, the beam expansion, multiple reflection, calibration, transmission and fiber spectrum analysis of the ultraviolet fiber and the fiber spectrometer to obtain the gas spectrum analysis result;

The transmission control unit communicates with the optical fiber spectrometer to realize gas data collection, analysis, processing and uploading.

In order to optimize the above technical solutions, the specific measures taken also include:

The above-mentioned ultraviolet light source is a deuterium lamp, the spectral range covers the ultraviolet spectrum of 180-400nm, the diameter of the light-emitting surface is Φ1mm, and the deuterium lamp has a multi-wing aluminum alloy housing.

The above-mentioned lens group is a collimating lens group, which adopts the structure type of Galileo telescope inverted. The front lens group is a short focal length positive lens, and the rear lens group adopts a positive lens group formed by a combination of positive and negative lenses. The lenses are all made of quartz (JGS1 ) Glass, and are coated with 180-400nm UV antireflection coating.

The above-mentioned ultraviolet multiple reflection pool is conjugated by concave spherical mirrors A, B and C with the same radius of curvature. Mirror A is the main mirror, mirrors B and C are secondary mirrors, and mirrors B and C are placed side by side. ；

The substrates of the mirrors A, B and C are made of K9 glass, plated with reinforced aluminum film, and the reflectivity of the ultraviolet 190～310nm band is greater than 90%;

The ultraviolet multiple reflection cell adopts the Whtie type, and the gas absorption optical path in the White cell is calculated by the formula:

L _a =n×L=2(N+1)×L

Among them, N is the number of light spots on the main mirror, and L is the cavity length of the White cell;

The cavity of the White cell is 600mm long, reflects 20 times back and forth, and the entire gas absorption optical path is 12m.

The above-mentioned automatic calibration cell adopts an aspheric single lens as the objective lens, and the specific parameters of the aspheric lens are: clear aperture Ф24mm, center thickness 5.75mm, focal length 50mm, eccentricity e ² =-0.59, material is JGS1, Coated with 180～400nm UV antireflection coating.

The ultraviolet absorption rate of the above-mentioned ultraviolet optical fiber is less than 10%.

The above-mentioned optical fiber spectrometer adopts a symmetrical Czerny-Turner optical structure, and uses two concave mirrors to replace the single mirror used in the Fastie-Ebert device;

The optical fiber spectrometer has a wavelength range of 185-340nm, uses a 2048-unit linear array ultraviolet-sensitive silicon CCD and a 1800-line blazed grating, a slit width of 50 microns, and a wavelength resolution better than 0.5nm.

The above-mentioned transmission control unit adopts DSP series single-chip microcomputer as the control core, adopts RS232/RS485 standard communication interface, and has a wireless communication module.

The aforementioned gas spectrum analyzer uses a multi-component DOAS filtering algorithm, which is a combination of binomial coefficient filtering, polynomial fitting filtering, and Savitzky-Golay filtering.

The present invention has the following beneficial effects:

1. The present invention uses ultraviolet light as the light source, which is not easily absorbed by water molecules, and can directly analyze moist gas;

2. Compared with the traditional DOAS system, the present invention is characterized by the use of multiple reflection pool technology instead of the open optical path. According to the principle of the Lambet-Beer law to determine the gas concentration, the detection sensitivity can be improved by increasing the detection optical path, and the multiple reflection pool is used. The light beam can be reflected multiple times in a small volume, and the absorption path of the gas can be significantly increased, thereby achieving the following advantages:

Small volume: the volume of the equipment is less than 0.2 cubic meters;

High precision: the detection limit can reach below 100ppb, and the detection limit of some gases such as SO2, NH3 can reach below 5ppb;

Quick response: the response time is less than 45s;

Simultaneous multi-gas monitoring: It can monitor the concentration of _{NH 3} , NO ₂ _{, SO 2} , CS ₂ , benzene, toluene, formaldehyde, butadiene and other gases at the same time.

3. The present invention is different from the point measurement of the traditional electrochemical sensor, and uses a small ultraviolet multiple reflection cell to realize the linear measurement within the optical path range, so that the measurement result is more representative and reliable.

4. The present invention adopts a multi-component DOAS filter algorithm to solve the problems of ultraviolet band environment and multi-component cross-interference, and improve the accuracy and accuracy of monitoring.

Description of the drawings

Figure 1 is a schematic diagram of modular links of a gas spectrum analyzer of the present invention;

Figure 2 is a spectrogram of a deuterium lamp;

Figure 3 is a diagram of the optical path system of the lens group;

Figure 4 is a diagram of the optical path system of the multiple reflection pool;

Figure 5 is a graph of the spectral reflectance of the reflecting pool;

Fig. 6 is a schematic diagram of the optical path of an aspherical focusing lens;

Figure 7 is a diagram showing the light spots of an aspherical focusing lens;

Figure 8 is a graph of broadband and narrowband in the absorption spectrum;

The reference signs are: ultraviolet light source 1, lens group 2, ultraviolet multiple reflection cell 3, automatic calibration cell 4, ultraviolet optical fiber 5, optical fiber spectrometer 6 and transmission control unit 7.

Detailed ways

The embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings.

The gas spectrum analyzer of the present invention is based on Beer-Lambert's law, adopts a unique ultraviolet spectrum detection structure, uses differential absorption spectroscopy technology, a combination of a small ultraviolet multiple reflection pool and a fiber optic spectrometer to realize the detection of a variety of polluted gases Real-time online monitoring. Through the small ultraviolet multiple reflection pool technology, the optical path is greater than 10 meters, the reflectance is improved, the stray light is reduced, the monitoring accuracy is improved, the volume is reduced, and the sensitivity and portability requirements of unorganized emission field detection are achieved.

Through the Multi-Filter technology combining binomial coefficient filtering, polynomial fitting filtering and Savitzky-Golay filtering and other digital filtering methods, according to the gas absorption characteristics, the multi-component DOAS filtering algorithm is adopted to solve the ultraviolet band environment and multi-component Cross-interference issues improve the accuracy and accuracy of monitoring.

As shown in Figure 1, a gas spectrum analyzer of the present invention includes an ultraviolet light source 1, a lens group 2, an ultraviolet multiple reflection cell 3, an automatic calibration cell 4, an ultraviolet optical fiber 5, an optical fiber spectrometer 6 and a transmission control unit 7;

Wherein, the ultraviolet light source 1, the lens group 2, the ultraviolet reflection cell 3, and the automatic calibration cell 4 constitute a unique ultraviolet spectrum detection structure;

The ultraviolet light source 1 passes through the lens group 2, the ultraviolet multiple reflection cell 3, the automatic calibration cell 4, the ultraviolet optical fiber 5, and the optical fiber spectrometer 6 in sequence;

The ultraviolet light source 1 passes through the lens group 2, the ultraviolet multiple reflection cell 3, the automatic calibration cell 4, the beam expansion, multiple reflection, calibration, transmission and optical fiber spectrum analysis of the ultraviolet optical fiber 5 and the optical fiber spectrometer 6, to obtain a gas spectrum analysis result;

The transmission control unit 7 communicates with the optical fiber spectrometer 6 to realize gas data collection, analysis, processing and uploading.

As shown in FIG. 2, in the embodiment, the ultraviolet light source 1 is a deuterium lamp with a spectral range covering the ultraviolet spectrum of 180-400 nm, and the diameter of the light-emitting surface is about Φ1 mm. The deuterium lamp has a multi-wing aluminum alloy housing.

The surface temperature of the deuterium lamp is very high when the system is working. In order to ensure the reliability and stability of the deuterium lamp and prolong the working life of the deuterium lamp, a multi-wing aluminum alloy shell is designed, the deuterium lamp is built in, and diffusion coordination is adopted. The method of heat transfer, and then use forced air cooling to meet the temperature requirements.

The designed device can adjust the position of the light-emitting surface of the deuterium lamp and can be fixed. On the one hand, the heat dissipation efficiency of the deuterium lamp is improved. On the other hand, the heat sink also has the function of reducing stray light and protecting the light source system.

In the embodiment, the lens group 2 is a collimating lens group, which can also be called a beam expander. In order to avoid the divergence of the spot caused by the excessively large divergence angle of the deuterium lamp beam, and to increase the transmission distance of the beam, that is, to reduce the divergence angle of the beam and improve the collimation, a beam expander is designed to improve its divergence angle.

The Galileo telescope is inverted. The front lens is composed of a short focal length positive lens. The divergent beam of the deuterium lamp is initially collimated, and a certain object aperture angle is ensured to receive as much light energy as possible. The lens adopts a positive lens group formed by a combination of positive and negative lenses to correct spherical aberration. By controlling the distance between the three lenses and the thickness of each lens, the beam of the deuterium lamp can be better collimated, and its divergence angle is controlled at about 1°, as shown in Figure 3.

The lenses are all made of quartz (JGS1) glass, and are coated with a 180-400nm ultraviolet antireflection coating, so as to better improve the transmittance of the ultraviolet light beam.

As shown in FIG. 4, in the embodiment, the ultraviolet multiple reflection pool 3 is conjugated by concave spherical mirrors A, B and C with the same radius of curvature. The mirror A is the primary mirror, and the mirrors B and C are the secondary mirrors. Mirrors, mirrors B and C are placed side by side;

The loss of light intensity in the white cell is mainly caused by gas absorption and the low reflectivity of the lens, which puts high demands on the UV coating technology. The substrate of the concave reflector is made of K9 glass, and the polishing is as high as possible to improve the coating efficiency. Because the coating wavelength band is too wide, the method of coating enhanced aluminum film is used to increase the reflectivity, and the reflectivity of the ultraviolet 190-310nm band is about 90%, as shown in Figure 5.

L _a =n×L=2(N+1)×L

Since the toxic gas content in the atmosphere is in the ppb～ppm order, in order to reduce the lower detection limit of the instrument so that it can meet the requirements for trace gas detection, according to the principle of Lambet-Beer law to determine the gas concentration, the detection optical path can be increased. Improve the detection sensitivity, the use of multiple reflection cells can make the beam multiple reflections in a small volume, so that the gas absorption path length can be significantly increased. Taking into account the portability of the system and the requirements of the gas to be measured, the cavity length of the White cell is 600mm, reflected 20 times back and forth, and the entire gas absorption optical path is 12m, and N=9 can be obtained from the formula. .

In the embodiment, the auto-calibration cell 4 adopts an aspheric single lens as the objective lens, which is a simple objective lens to form a focusing system of the coupled fiber, which solves the problem that due to the large divergence angle of the outgoing beam itself, the off-axis aberration is too large. A small spot is formed, which leads to the problem of energy loss.

The specific parameters of the aspheric lens are: a clear aperture of Ф24mm, a center thickness of 5.75mm, a focal length of 50mm, an eccentricity e ² =-0.59, a material of JGS1, and a 180-400nm UV antireflection coating, as shown in FIG. 6. The light spot sequence diagram of the aspheric surface before and after correction in the receiving field of view is shown in Figure 7.

In the embodiment, the ultraviolet optical fiber 6 adopts a customized high-performance ultraviolet optical fiber, which has a small dispersion coefficient, an ultraviolet absorption rate lower than 10%, and a high mechanical strength.

In the embodiment, the optical fiber spectrometer 6 considers that increasing the groove density of the diffraction grating can improve the optical resolution, but at the expense of the spectral range and signal strength; reducing the slit width or fiber diameter can improve the optical resolution. Resolution, this will cause a decrease in signal strength. By studying the absorption characteristics of the polluted gas in the ultraviolet band, the symmetrical Czerny-Turner optical structure design can not only avoid the stray light generated by additional absorption and scattering, but also reduce the volume of the spectrometer. The fiber optic spectrometer 6 has a wavelength range of 185-340nm, using 2048-unit linear array ultraviolet-sensitive silicon CCD, a slit width of 50 microns, and a wavelength resolution better than 0.5nm.

In the embodiment, the transmission control unit 7 adopts DSP series single-chip microcomputer as the control core, adopts RS232/RS485 standard communication interface, has a wireless communication module, and can directly upload the collected data to the server platform.

The shell of the present invention uses aluminum alloy material, and the overall volume is less than 0.2 cubic meters.

In an embodiment, the gas spectrum analyzer uses a multi-component DOAS filtering algorithm, which is a combination of binomial coefficient filtering, polynomial fitting filtering, and Savitzky-Golay filtering.

The DOAS technology used in the gas spectrum analyzer, in the actual gas measurement, in addition to molecular absorption, there are also scattering phenomena. When the beam passes through the gas mass to be measured, it will encounter Rayleigh scattering, Mie scattering and Raman scattering. Among them, Rayleigh and Raman scattering are caused by gas molecules, while M scattering is caused by aerosol particles or smoke. Therefore, Lambert-Beer law cannot be directly used for actual atmospheric measurement.

In the example, the DOAS technology realizes qualitative and quantitative measurement by analyzing the "fingerprint" absorption of light radiation by different molecules. Therefore, other processes are considered disturbances and need to be removed. Both M scattering and Rayleigh scattering change slowly with the wavelength, and have a greater impact on the weakening of the light intensity; fluorescence (secondary luminescence λ'>λ) and Raman scattering (anti-Stokes and Stokes rays produced) The bars are respectively λ'=λ±λv) depends on the internal structure of the molecular energy level, and has little effect on the weakening of light intensity. Therefore, it can be described as:

In the formula, I ₀ (λ) is the emitted light intensity; I (λ) is the received light intensity after atmospheric absorption; σ _i (λ) is the absorption cross section of the i-th gas molecule; L is the optical path; c _i is The average concentration of the i-th gas molecule in the optical path. ε _R (λ) and ε _M represent the light intensity attenuation caused by Rayleigh scattering and M scattering, respectively.

The basic principle of DOAS technology is to solve this problem by dividing the absorption cross section into two parts.

σ _i (λ)=σ _i,b (λ)+σ′ _i (λ)

Wherein σ _{i, b} (λ) slowly varying with wavelength λ, σ _'i (λ) with wavelength [lambda] is a rapid change in shape portion. The broadband and narrowband parts of the absorption spectrum are shown in Figure 8.

After the section is divided into two parts, it can be expressed as:

I(λ)=I ₀ (λ)·exp[-L∑(σ′ _i (λ)c _i )]·exp[-L(∑(σ _i,b (λ)c _i )+ε _R (λ )+ε _M (λ)))·A(λ)

In the formula, the first exponential function describes the differential absorption of trace gases; the second term is the slow-varying absorption of trace gases in the atmosphere and the effects of Rayleigh and M scattering, and the attenuation factor A(λ) describes the optical transmission with wavelength Slow change. We define the variable I′ ₀ (λ) to represent the light intensity without differential absorption, that is, the slow-changing part:

I′ ₀ (λ)=I ₀ (λ)·exp[-L(∑(σ _i,b (λ)c _i )+ε _R (λ)+ε _M (λ))]·A(λ)

Then the equation becomes:

I(λ)=I′ ₀ (λ)×exp[-L∑(σ′ _i (λ)c _i )]

I (λ) of the absorbent structure contains only a narrow band; I _'0 is interpolated intensity to a certain kind of a sufficiently narrow absorption line. σ(λ) is usually measured in the laboratory (or obtained from the literature), and then numerically filtered to obtain the differential absorption cross-section σ'(λ). Obtain the differential optical density:

D′=log(I′ ₀ (λ)/I(λ))=L∑(σ′ _i (λ)c _i )

Knowing L and deriving D'and σ'(λ) from D and σ(λ), the concentration of a certain molecule can be calculated.

Since gas molecules have their own characteristic absorption cross sections, the concentration can be determined by studying the characteristic absorption of light radiation by gas.

In an embodiment, the gas spectrum analyzer has a monitoring range covering the near-ultraviolet spectrum with a wavelength of 185-340 nm, and supports simultaneous monitoring of the content of multiple gases.

The gas spectrum analyzer of the present invention adopts a small ultraviolet multiple reflection pool 4, which not only increases the optical path but also reduces the volume, so that the device has a compact structure, a small enclosure, and is convenient for installation and transportation.

The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments. All technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

A gas spectrum analyzer, which is characterized in that it includes an ultraviolet light source (1), a lens group (2), a small ultraviolet multiple reflection cell (3), an automatic calibration cell (4), an ultraviolet optical fiber (5), and an optical fiber spectrometer ( 6) and transmission control unit (7);

The ultraviolet light source (1), lens group (2), small ultraviolet multiple reflection cell (3) and automatic calibration cell (4) constitute an ultraviolet spectrum detection structure;

The ultraviolet light source (1) sequentially passes through the lens group (2), the small ultraviolet multiple reflection cell (3), the automatic calibration cell (4), the ultraviolet optical fiber (5) and the optical fiber spectrometer (6);

The ultraviolet light source (1) sequentially passes through the beam expansion and multiple reflections of the lens group (2), the small ultraviolet multiple reflection pool (3), the automatic calibration pool (4), the ultraviolet optical fiber (5) and the optical fiber spectrometer (6) , Calibration, transmission and optical fiber spectrum analysis to obtain gas spectrum analysis results;

The transmission control unit (7) communicates with the optical fiber spectrometer (6) to realize gas data collection, analysis, processing and uploading.
A gas spectrum analyzer according to claim 1, characterized in that:

The ultraviolet light source (1) is a deuterium lamp with a spectral range covering an ultraviolet spectrum of 180-400 nm, a diameter of a light-emitting surface of Φ1 mm, and the deuterium lamp has a multi-wing aluminum alloy housing.
A gas spectrum analyzer according to claim 1, characterized in that:

The lens group (2) is a collimating lens group with a beam expander to improve its divergence angle;

The said lens group (2) adopts the structure type of Galileo telescope inverted, and the front group lens is composed of a short focal length positive lens, which preliminarily collimates the divergent light beam of the deuterium lamp and ensures a certain aperture angle of the object. To receive as much light energy as possible, the rear lens group adopts a positive lens group formed by a combination of positive and negative lenses to correct spherical aberration; by controlling the distance between the three lenses and the thickness of each lens, the beam of the deuterium lamp can be better collimated Straight, its divergence angle is controlled at about 1°.

The lenses are all made of quartz glass, and are coated with a 180-400nm ultraviolet antireflection film.
A gas spectrum analyzer according to claim 1, characterized in that:

The ultraviolet multiple reflection pool (3) is conjugated by concave spherical mirrors A, B and C with the same radius of curvature. The mirror A is the main mirror, the mirrors B and C are the secondary mirrors, and the mirrors B and C are side by side. place;

The substrates of the mirrors A, B and C are made of K9 glass, plated with reinforced aluminum film, and the reflectivity of the ultraviolet 190～310nm band is greater than 90%;

The ultraviolet multiple reflection cell adopts the Whtie type, and the gas absorption optical path in the White cell is calculated by the formula:

L a =n×L=2(N+1)×L

Among them, N is the number of light spots on the main mirror, and L is the cavity length of the White cell;

The cavity of the White cell is 600mm long, reflects 20 times back and forth, and the entire gas absorption optical path is 12m.
A gas spectrum analyzer according to claim 1, characterized in that:

The automatic calibration cell (4) adopts an aspheric single lens as the objective lens. The specific parameters of the aspheric lens are: clear aperture Ф24mm, center thickness 5.75mm, focal length 50mm, eccentricity e 2 =-0.59, and the material is JGS1 , Coated with 180～400nm UV antireflection coating.
A gas spectrum analyzer according to claim 1, characterized in that:

The ultraviolet absorption rate of the ultraviolet optical fiber (6) is lower than 10%.
A gas spectrum analyzer according to claim 1, characterized in that:

The optical fiber spectrometer (6) adopts a symmetrical Czerny-Turner optical structure, and replaces a single reflector used in the Fastie-Ebert device with two concave reflectors;

The optical fiber spectrometer (6) has a wavelength range of 185-340 nm, uses 2048-unit linear ultraviolet-sensitive silicon CCD and 1800 line blazed grating, the slit width is 50 microns, and the wavelength resolution is better than 0.5 nm.
A gas spectrum analyzer according to claim 1, characterized in that:

The transmission control unit (7) adopts DSP series single-chip microcomputer as the control core, adopts RS232/RS485 standard communication interface, and has a wireless communication module.
A gas spectrum analyzer according to claim 1, characterized in that:

The gas spectrum analyzer adopts a multi-component DOAS filtering algorithm, which is a combination of binomial coefficient filtering, polynomial fitting filtering, and Savitzky-Golay filtering.