Method for measuring gas absorption spectrum line width and line-type coefficient based on wavelength modulation

A technology of gas absorption and wavelength modulation, applied in color/spectral characteristic measurement, spectrometry/spectrophotometry/monochromator, measuring device, etc., can solve line fitting error and high harmonic signal attenuation Fast, low signal-to-noise ratio, etc., to achieve the effect of convenient reading, eliminating laser intensity, and high signal-to-noise ratio

Active Publication Date: 2013-09-25
北京新叶科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for weak absorption conditions, high-order harmonic signals attenuate quickly and the signal-to-noise ratio is low, resulting in large errors in line shape fitting, so this method is more suitable for strong absorption environments

Method used

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  • Method for measuring gas absorption spectrum line width and line-type coefficient based on wavelength modulation
  • Method for measuring gas absorption spectrum line width and line-type coefficient based on wavelength modulation
  • Method for measuring gas absorption spectrum line width and line-type coefficient based on wavelength modulation

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Embodiment

[0060] 1) The embodiment adopts CO 2 As an example, measuring CO 2 The linewidth and shape coefficient of the absorption line. CO Control with Flow Meter 2 The gas concentration X=13.71%, the pressure P=41mbar and the temperature T=297.7K of the gas medium 9 are measured by the pressure sensor 5 and the temperature sensor 6, and the laser absorption path L=120cm is set, and the absorption rate of the gas is 4.65 %;

[0061] 2) Select CO from the spectral database 2 The center frequency υ of the absorption spectrum 0 , line strength S(T), self-widening coefficient γ self and the air widening factor γ air Table 1 below:

[0062] Table 1CO 2 Molecule 6982.0678cm -1 Spectral constant of the spectral line (298K)

[0063]

[0064] 3) Take the tunable semiconductor laser 3 as the light source, and use the laser controller 2 to control the output frequency of the tunable semiconductor laser 3 to be stable at the central frequency υ 0 =6982.0678cm -1 place;

[0065] 4) ...

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Abstract

The invention discloses a method for measuring the gas absorption spectrum line width and the line-type coefficient based on wavelength modulation. According to the method for measuring the gas absorption spectrum line width and the line-type coefficient based on the wavelength modulation, the specific value between a two-time harmonic and a four-time harmonic in the wavelength modulation spectrum technology are adopted to measure the line width and the line-type coefficient of the spectral line absorbed by the gas. During measurement, the line width and the line-type of the gas absorption spectrum line to be measured are calculated by means of analysis of the specific value between the two-time harmonic and the four-time harmonic. The method for measuring the absorption gas spectrum line width and the line-type coefficient based on the wavelength modulation has the advantages of being easy to operate, high in measuring precision, and capable of eliminating influence of factors such as background signals, laser intensity fluctuation and the photoelectricity amplification coefficient, solving the problem that an existing WMS technology can not accurately measure the line-type parameters absorbed by the gas and broadening the application range of the WMS technology and the like. Due to the fact that the specific value between the two-time harmonic and the four-time harmonic are adopted to calculate the gas absorption line-type parameters, the method for measuring the gas absorption spectrum line width and the line-type coefficient based on the wavelength modulation can be called the R24 method.

Description

technical field [0001] The invention relates to a method for measuring the line width and line coefficient of gas absorption spectrum based on wavelength modulation. The method first proposes and realizes the on-line measurement of line width and line coefficient of gas absorption spectrum by wavelength modulation method. Background technique [0002] Tunable diode laser absorption spectroscopy (TDLAS) technology uses a narrow-band laser to scan the absorption line of the gas, and obtains the temperature and concentration of the gas to be measured by analyzing the laser intensity absorbed by the gas. Compared with the traditional sampling gas detection technology, TDLAS technology has the advantages of non-contact online measurement, strong selectivity, high sensitivity, and fast online response speed. It can measure the average level of gas concentration in a certain area, and has become the current gas concentration Important development direction and technical mainstream ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01J3/433G01N21/39
Inventor 彭志敏丁艳军蓝丽娟
Owner 北京新叶科技有限公司
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