Abstract:
The design and frabication of a Helmholtz type gas phase photoacoustic cell are described. The cell which incorporates a miniature microphone (Knowles B.T.1759) along with a matching pre-amplifier is very sensitive and can detect very weak signals. The system can be effectively used for the study of overtone spectroscopy of molecules in gas phase and it is suitable for both intracavity and extracavity modes of operation. The working of the cell is illustrated by recording overtone photoacoustic spectrum of Toluene in the extracavity mode using a Ring dye Laser. Variation of the amplitude and phase of photoacoustic signal with modulating frequency are also studied along with the dependence of photoacoustic signal with laser power
