SU1320723A1 - Microwave spectrometer - Google Patents

Abstract

The invention can be used for spectrometry of gases in the submillimeter wavelength range and provides an increase in the accuracy of measuring the frequencies of spectral lines. The microwave spectrometer contains a source of microwave radiation 1, consisting of a tunable generator (PG) 2 and a controlled power supply unit 3, a radiation divider 4, cells 5,6, respectively, with the test gas and a gas with known spectral characteristics, microphones 7,8, tunable Fabry-Perot cavity 9, microwave radiation detector 10, Michelson interferometer 11, coherent optical radiation source 12, photoreceiver 13, amplifiers 14-16, synchronous detectors 17-19, recorder 20, modulating oscillator 21 voltage and an element 22 for moving the movable mirror of the resonator 9. The frequency tunable oscillator radiation 2 is automatically tuned to its own frequency resonator 9. When moving .podvizhnogo mirror element 22 via osztdestvl a frequency scan over a range of radiation. When the frequency of the radiation coincides with the frequencies of the absorption lines of the gases in the cells 5,6, signals appear that are recorded by the recorder 20. 1 sludge. yu (L with yu ohch SLE

Description

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The invention relates to a technique for measuring on microwave and can be used for spectrometry of gases in the submillimeter wavelength range.

The aim of the invention is to improve the accuracy of measuring the frequencies of spectral lines.

The drawing shows a structural diagram of a microwave spectrometer

The microwave spectrometer contains a source of microwave radiation 1, which, for example, includes a tunable generator 2 and a controlled power supply unit 3, a radiation divider 4, the first 5 and the second 6 cells with the test gas and gas with the known spectral characteristics, first 7 and second 8 microphones, tunable resonator 9 Fabry-Perot, microwave radiation detector 10, Michelson interferometer 11, coherent optical radiation source 12 (He-Ne laser), photodetector 13, amplifiers 14-16, first 17, second 18 and third 19 synchronous detectors, recorder 20, modulating voltage generator 21, and element 22 for moving the movable mirror of the Fabry-Perot cavity 9.

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Microwave spectrometer works as follows.

The frequency modulated radiation of generator 2 of source 1 is split by a divider of radiation 4 into two beams, one of which is directed to the first 5 and second 6 cells, and the other to the Fabry-Perot cavity 9 tuned to the frequency of the radiation. When the radiation frequency deviates from the natural frequency of the resonator 9, a signal with a frequency equal to the modulation frequency arises at the detector 10, which after amplifier 14 and synchronous detector 17 goes to the controlled power supply unit 3 of source 1 and changes its output voltage so as to eliminate this is a deviation. Thus, the emission frequency of the tunable oscillator 2 is automatically tuned to the natural frequency of the Fabry-Perot resonator 9. When the moving mirror of the Fabry-Perot cavity 9 is smoothly moved, for example, element 22 is used to scan the radiation frequency over the range. When the frequency of radiation coincides with the frequencies of the absorption lines of gases in

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The first 5 and 6 second cells receive signals that are recorded by the first 7 and second 8 microphones and, after synchronous detection, the first and second synchronous detectors arrive at the first and second inputs of the recorder 20.

In this way, the spectra of both the test and known reference gases are recorded. Simultaneously with the recording of the spectra, the interferogram from Michelson's 11 interferometer 11, which is connected to the Fabry-Perot cavity 9, is fed to the third input of the three-channel recorder so that the movable mirror of the resonator 9 is simultaneously a movable mirror of the interferometer 11. As a result, the interferogram periods are connected with the frequency of radiation tunable, generator 2 of source 1 and are marks of the exact frequency scale on the recording of the spectrum.

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Claims (1)

Invention Formula Microwave spectrometer containing placed along one axis 30 microwave source tunable in frequency, the first and second cells to accommodate the test gas and gas with known spectral characteristics, respectively, which are connected to microphones connected respectively to the signal inputs of the first and second Synchronous detectors, to which their inputs An output of a modulating voltage generator is not connected, the outputs of the first and second synchronous detectors are connected to the first and second inputs of the recorder, respectively, while the output is 4 5 pa of modulating voltage is connected to the first input of a microwave radiation source, characterized in that, in order to improve the accuracy of measuring the frequencies of the spectrum. 50 straight lines, a series-connected radiation divider, installed between the microwave source and the first cell, tunable Fabry 5 Perot resonator, microwave radiation detector and the third synchronous detector, the main input of which is connected to the output of the modulating voltage generator, and the output to the second input is313207234 microwave radiation source, and the movable mirror of which is also series-connected by a non-movable mirror of the resonator, the Perot coherent optical fabricator, and the photodetector connected to the Michelson interferometer to the third input of the recorder.