Photoacoustic spectroscopy for detection of trace C2H2 using ellipsoidal photoacoustic cell

A novel photoacoustic spectroscopy gas sensor based on a micro-resonator has been developed. The photoacoustic cell was designed and fabricated using 3-D printing and the photoacoustic cell volume was compressed significantly. This design greatly reduces the time of manufacturing the micro-resonator and the weight was lighter compared to traditional cells. Furthermore, the acoustic pressure distribution in the 3-D printed photoacoustic cell was analyzed by COMSOL Multiphysics software, which indicated that the strongest acoustic pressure occurred in the middle of the resonant cavity. The performance of the sensor was evaluated by detection of CH4 at normal atmospheric pressure used a near infrared distributed feedback laser emitted at 1653 nm. The characteristic of the photoacoustic signal under different pressures was also investigated. An Allan variance shows that the 3-D printed photoacoustic spectroscopy sensor has the detection limit of 1.44 ppmv (3σ) for CH4 detection at about 200 s integration time.

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CO2-laser photoacoustic spectroscopy applied to low-level toxic-vapor monitoring

Canadian Journal of Physics ◽

10.1139/p86-194 ◽

1986 ◽

Vol 64 (9) ◽

pp. 1124-1131 ◽

Cited By ~ 9

Author(s):

G. L. Loper ◽

J. A. Gelbwachs ◽

S. M. Beck

Keyword(s):

Co2 Laser ◽

Photoacoustic Spectroscopy ◽

Ambient Air ◽

Detection Capability ◽

Photoacoustic Cell ◽

Low Concentration ◽

Low Level ◽

Laser Photoacoustic Spectroscopy ◽

Industrial Compounds

A CO2-laser photoacoustic detector is being developed that can detect the hazardous hydrazine-based rocket fuels and selected toxic industrial compounds at concentrations below 100 ppb in the ambient air. This paper reviews our work to develop this detector based on the principles of photoacoustic spectroscopy and classical acoustics. The low parts-per-billion level detection capability of the method to the hydrazines is demonstrated with both acoustically nonresonant and resonant photoacoustic cell designs. A flowing, resonant photoacoustic cell whose interior is coated with tetrafluoroethylene Teflon has been shown to be preferred for detecting highly adsorptive or reactive compounds. Photoacoustic spectroscopy has been demonstrated to be useful in measuring adsorption or reaction losses of low-concentration gases on surfaces.

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Comparison of the CRLC Models Describing the Helmholtz Type Cells for the Nondestructive Photoacoustic Spectroscopy

Metrology and Measurement Systems ◽

10.2478/mms-2014-0046 ◽

2014 ◽

Vol 21 (3) ◽

pp. 545-552 ◽

Cited By ~ 7

Author(s):

Łukasz Bartłomiej Chrobak ◽

Mirosław Andrzej Maliński

Keyword(s):

Experimental Data ◽

Photoacoustic Spectroscopy ◽

Frequency Data ◽

Photoacoustic Cell ◽

Photoacoustic Method

Abstract The photoacoustic cell is the heart of the nondestructive photoacoustic method. This article presents a new simple lumped-components CRLC model of the Helmholtz type photoacoustic cell. This model has been compared with the well known literature models describing the Helmholtz type cells for photoacoustic spectroscopy. Experimental amplitude and phase frequency data obtained for the two photoacoustic cells have been presented and interpreted in a series of models. Results of the fitting of theoretical curves, obtained in these models, to the experimental data have been shown and discussed.

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