Tunable resonant photoacoustic cell

Abstract

The invention discloses a tunable resonant photoacoustic cell comprising a light source, a modulation device, a tunable photoacoustic cell body, a tuning device, a high-sensitivity acoustic sensor, alock-in amplifier and a computer, and the tunable Helmholtz photoacoustic cell body comprises a light window, an air inlet, an air outlet and a Helmholtz photoacoustic cell cavity. The Q value of thesystem is greatly increased through resonance frequency resonance of the tunable Helmholtz photoacoustic cell and the torsion beam acoustic sensor, and the signal-to-noise ratio and the detection sensitivity of the system are remarkably improved in combination with the background noise suppression capability of the torsion beam acoustic sensor. Compared with a traditional temperature control tuning method, the mechanical tuning mode can achieve rapid adjustment, the anti-interference capability is high, and matching with the resonant frequency of the acoustic sensor is easy to achieve.

Description

technical field [0001] The invention relates to the field of photoacoustic spectrum detection, in particular to a tunable resonant photoacoustic cell. Background technique [0002] In recent years, with the frequent occurrence of global natural disaster pollution sources and the aggravation of man-made pollution sources, the problem of air pollution has attracted widespread attention. Among them, the state of the pollution source is divided into two states: aerosol and gas. Compared with the pollution source in the aerosol state, the monitoring and processing technology of the concentration of the gas pollution source and component analysis poses greater challenges to scientific and technological personnel. Photoacoustic spectroscopy detection technology is used in air pollution important applications in the detection process. This detection technology not only has its own huge advantages in the detection of gas pollutant characteristics, but also has been fully reflected i...

AI Technical Summary

Problems solved by technology

The disadvantage of this temperature-controlled tuning method is that due to the large volume and mass of the photoacoustic cell, the speed of the temperature compensation method will be very slow, and it is difficult to achieve a uniform change, and the factors that affect the resonance frequency drift are often very large. Fast, such as gas pressure fluctuations, etc., so the effect of using this tuning method to achieve resonance is poor

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