Cantilever beam and photoacoustic cell double-resonance enhanced-type photoacoustic spectrum detection system and method

Abstract

The invention discloses a cantilever beam and photoacoustic cell double-resonance enhanced-type photoacoustic spectrum detection system and a method, and belongs to the technical field of trace gas detection. According to the cantilever beam and photoacoustic cell double-resonance enhanced-type photoacoustic spectrum detection system and the method, sound wave generated by excitation of gas molecules with a light source is subjected to coherence stack in an acoustic resonance tube of a resonant photoacoustic cell, so that photoacoubtic signal amplitude is increased effectively; at the same time, fine adjustment on the photoacoustic cell resonant frequency is realized through precise design and temperature control of a cantilever beam structure, so that accurate matching of the cantilever beam resonant frequency with the photoacoustic cell resonant frequency is realized, and the photoacoubtic signals are enhanced further via one step resonant of the cantilever beam; the double-resonanceenhanced-type photoacoustic spectrum method is combined with a phase-locked amplifier to realize super sensitive gas detection. The double-resonance enhancing effect of the cantilever beam and the photoacoustic cell is capable of realizing obvious amplification of photoacoubtic signals, the system working frequency is controlled at kHz order of magnitude, 1 / f noise is reduced greatly, and a technological scheme with competitiveness is provided for super low concentration gas detection.

Description

technical field [0001] The invention belongs to the technical field of trace gas detection, and relates to a dual-resonance enhanced photoacoustic spectrum detection system and method of a cantilever beam and a photoacoustic cell. Background technique [0002] Photoacoustic gas sensors have been widely used in the fields of dissolved gas analysis in transformer oil, environmental pollution gas monitoring, and flammable and explosive gas monitoring in coal mines due to their significant advantages such as high sensitivity and small sampling volume. [0003] In traditional photoacoustic spectroscopy detection, gas molecules absorb light energy and undergo non-radiative transitions to generate sound waves, which are usually converted into electrical signals by an electret microphone. According to the principle of photoacoustic spectroscopy, the sensitivity of photoacoustic measurements is proportional to the sensitivity of the acoustic wave detector. Compared with condenser mi...

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Problems solved by technology

[0004] The purpose of the present invention is to propose a cantilever beam and photoacoustic cell dual-resonance enhanced photoacoustic spectrum detection system and method, aiming to solve the problems of limited photoacoustic signal enhancement effect and large 1 / f noise in the traditional CEPAS measurement method To further improve the gas detection sensitivity of the CEPAS system, and expand a larger space for the application of photoacoustic spectroscopy in trace gas detection

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