METHOD AND DEVICE FOR MEASURING CONCENTRATION OF GASES Russian patent published in 2008 - IPC G01N21/27 

FIELD: measuring technique.

SUBSTANCE: method comprises generating information beam from the sample and reference beam when radiation is generated at a frequency of absorption line of the spectrum of the agent to be investigated and combining the information and reference beams to generate a resulting signal that is used for determining the presence and/or concentration of the agent to be investigated in the sample. The information beam from the sample and the reference beam are preliminary generated at a frequency out of the line of absorption of the agent to be investigated. The beams are combined to produce a zero signal by means of leveling the amplitudes of the information and reference beams. The leveling is performed when they are in antiphase, and intensity of the resulting signal at a frequency of the absorption line of the spectrum of the agent to be investigated is measured when the information and reference beams are in antiphase and is equal to the intensity of information beam absorbed by the agent. The device comprises source of electromagnetic radiation, unit for generating reference and information beams, and interferometer provided with reference arm and information arm and cell filled with the agent to be analyzed. The output of the interferometer is connected with the unit for generating resulting signal connected with the device for recording of the resulting signal and unit for control of parameters of the reference beam connected to the reference arm. The unit for control of the parameters of the reference beam has a unit for control of the amplitude that is made of a wedge of variable density and/or sloping mirror and unit for control of phase of the beam that is made of a mirror mounted on the substrate made of piezoelectric material.

EFFECT: enhanced precision.

5 cl, 1 dwg