Fotoakustická spektroskopia

Úvod Meranie CO2Fotoakustická spektroskopia

 

Meranie pomocou fotoakustickej spektroskopie

 

Fotoakustický efekt popísal už v roku 1880 Alexander Graham Bell . V súčasnosti je to výkonná metóda na štúdium koncentrácie plynov.

 

Fotoakustická spektroskopia

 

Description

   Exemplary assembly of a photoacoustic spectroscopefor gas analysis with an acoustic cell.

Resonance ocours at a wavelength of double the resonator length. Instead of a chopper wheel, variation of the absorption could also be achieved with a tunable laser, modulating its frequency across absorption wavelength. Additional λ/4 tube elements could be added for example in the gas inlet to prevent unwanted flow noises. Electronic control elements, especially a lock-in amplifier, are not shown.

  1. Light source (e. g. Laser)
  2. Chopper wheel
  3. semipermeable mirrors form an optical resonance system
  4. cell windows (tilted for polarisation)
  5. gas flow inlet and outlets
  6. buffer gas volumes
  7. acoustic sensor (e. g. microphone or transducer)
  8. resonator