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Tuning fork enhanced interferometric photoacoustic spectroscopy: A new method for trace gas analysis

 
: Köhring, M.; Pohlkötter, A.; Willer, U.; Angelmahr, M.; Schade, W.

:

Applied Physics. B 102 (2011), No.1, pp.133-139
ISSN: 0340-3793
ISSN: 0721-7269
ISSN: 0946-2171
ISSN: 1432-0649
English
Journal Article
Fraunhofer HHI ()

Abstract
A photoacoustic trace gas sensor based on an optical read-out method of a quartz tuning fork is shown. Instead of conventional piezoelectric signal read-out, as applied in well-known quartz-enhanced photoacoustic spectroscopy (QEPAS), an interferometric read-out method for measurement of the tuning fork's oscillation is presented. To demonstrate the potential of the optical read-out of tuning forks in photoacoustics, a comparison between the performances of a sensor with interferometric read-out and conventional QEPAS with piezoelectric read-out is reported. The two sensors show similar characteristics. The detection limit (L) for the optical read-out is determined to be L opt=(2598±84) ppm (1) compared to L elec=(2579±78) ppm (1) for piezoelectric read-out. In both cases the detection limit is defined by the thermal noise of the tuning fork.

: http://publica.fraunhofer.de/documents/N-189934.html