Photoacoustic spectroscopy gas detection system based on silicon cantilever beam and resonance tube matching with silicon cantilever beam

Abstract

The invention relates to a photoacoustic spectroscopy gas detection system based on a silicon cantilever beam and a resonance tube matching with the silicon cantilever beam. The system comprises an acoustic wave detection device composed of a silicon cantilever beam and a resonance tube matching with the silicon cantilever beam. The silicon cantilever beam comprises a homogeneous standard beam, a small fan beam, a large fan beam and a wedge beam. The middle of the resonance tube has a channel. The resonance tube is provided with a window communicated with the channel and a fixing table for arranging the silicon cantilever beam in the window position and also be provided with fastening double-screw bolts in two sides of the window, the fastening double-screw bolt is provided with a cantilever beam holding-down device fastened by nuts and used for pressing the silicon cantilever beam to the window of the resonance tube. The resonant frequency and vibration displacement are changed through replacement of cantilever beams having different structures according to actual demands so that photoacoustic signal detection sensitivity is improved. Through a Fabry-Perot cavity demodulation method, high detection precision and good sensitivity are realized.

Description

technical field [0001] The invention relates to the technical field of photoacoustic spectrum gas detection, in particular to a photoacoustic gas detection system based on a silicon cantilever beam and a matching resonant tube. Background technique [0002] The development of trace gas detection technology is of great significance to the monitoring of atmospheric environment, the long-distance detection of explosives and the detection of biological physiological state. Photoacoustic spectroscopy (PAS) has always been one of the most important development directions of trace gas detection technology due to its high sensitivity, large dynamic range, and detector response independent of incident wavelength. Spectroscopy technologies include conventional photoacoustic spectroscopy (CPAS for short) and quartz-enhanced photoacoustic spectroscopy (QEPAS for short), which can detect gases at ppb concentration levels. Acoustic Spectrum CPAS uses a microphone to detect photoacoustic ...

AI Technical Summary

Problems solved by technology

Photoacoustic spectroscopy (PAS) has always been one of the most important development directions of trace gas detection technology due to its high sensitivity, large dynamic range, and detector response independent of incident wavelength. Spectroscopy technologies include conventional photoacoustic spectroscopy (CPAS for short) and quartz-enhanced photoacoustic spectroscopy (QEPAS for short), which can detect gases at ppb concentration levels. Acoustic Spectrum CPAS uses a microphone to detect photoacoustic signals, which are easily affected by external noise. QEPAS uses a quartz tuning fork as an acoustic wave sensor to detect sound waves. The use of Fappaure cavity optical demodulation technology can make up for the weak electro-demodulation detection signal. , can be used for long-distance detection of flammable and explosive gases in harsh environments such as strong electromagnetic interference, high temperature, and high humidity. However, since the tuning fork used is a mass-produced low-cost standard tuning fork, its resonance frequency is 32.678kHZ, and its vibration displacement is On the order of tens of pm, in order to change the resonance frequency according to actual needs, increase the vibration displacement, and improve the detection sensitivity of photoacoustic signals, in order to overcome the defects and shortcomings of the existing technology, the patent of the present invention proposes a silicon cantilever and A photoacoustic spectroscopy gas detection system whose matching resonant tube is an acoustic wave detection device

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