Transversely Excited Multipass Photoacoustic Cell Using Electromechanical Film as Microphone

Sensors

Jaakko Saarela¹  Johan Sand¹  Tapio Sorvajärvi¹  Albert Manninen¹ 

[1] Optics Laboratory, Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland; E-Mails:

关键词: multipass;    photoacoustic;    spectroscopy;    longitudinal resonance;    transversal excitation;    transducer;    electromechanical film microphone;    EMFIT film;   

DOI  :  10.3390/s100605294

来源: mdpi

【 摘 要 】

A novel multipass photoacoustic cell with five stacked electromechanical films as a microphone has been constructed, tested and characterized. The photoacoustic cell is an open rectangular structure with two steel plates facing each other. The longitudinal acoustic resonances are excited transversely in an optical multipass configuration. A detection limit of 22 ppb (10⁻⁹) was achieved for flowing NO₂ in N₂ at normal pressure by using the maximum of 70 laser beams between the resonator plates. The corresponding minimum detectable absorption and the normalized noise-equivalent absorption coefficients were 2.2 × 10⁻⁷ cm⁻¹ and 3.2 × 10⁻⁹ cm⁻¹WHz^−1/2, respectively.

【 授权许可】

CC BY   
© 2010 by the authors; licensee MDPI, Basel, Switzerland.