Differential mode excitation photoacoustic spectroscopy: a new photoacoustic detection scheme.
Rev Sci Instrum
; 78(6): 063104, 2007 Jun.
Article
em En
| MEDLINE
| ID: mdl-17614602
ABSTRACT
A robust and simple gas sensor based on a novel photoacoustic scheme named "differential mode excitation photoacoustic spectroscopy (DME-PAS)" is presented. This method takes advantage of the selective excitation of two different modes in a resonant photoacoustic cell. A blackbody light source is used for simplicity in combination with optical correlation to provide a good selectivity. The frequency response of the proposed resonant cell is modeled using the extended Helmholtz resonator theory. The DME-PAS device is tested using acetone vapor and a model developed to describe its response when the gas concentration is varied. The obtained limit of detection is 25 ppm m(-1) for acetone in room air. Using DME-PAS, the derived gas concentration is affected neither by intensity fluctuations of the light source nor by any microphone drifts.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fotometria
/
Análise Espectral
/
Acústica
/
Gases
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
/
Prognostic_studies
Idioma:
En
Revista:
Rev Sci Instrum
Ano de publicação:
2007
Tipo de documento:
Article