METHOD AND APPARATUS FOR THE TRANSMISSION OF AN ACOUSTIC SIGNAL IN A PHOTOACOUSTIC CELL

摘要

In a method for the transmission of an acoustic signal to a microphone in a photoacoustic cell being part of an apparatus for photoacoustic analysis of substances or gases and in which the zone (40) containing a medium to be analysed represents a damaging environment to the microphone (10), the latter is connected to an excitation zone (30) through a waveguide (20) into which a protecting gas which is chemically neutral to the medium sample has been introduced between the microphone (10) and the medium to prevent the medium from reaching the microphone, the protecting gas being furthermore of a type which allows the waveguide (20) to transmit the acoustic signal generated in the medium through the protecting gas to the microphone without any significant weakening of the signal.