Acousto=optical gas analyser - having black body source, chopper, absorption chamber with gas sample, filter and microphone signal detector

摘要

Optico-acoustic gas analyser uses a radiation source the radiation from which passes through a chopper. The final beam is then measured by an opto-acoustic detector in the form of a condenser microphone. The light source is a back body. The beam passes through a positive interference filter formed from several solid film layers. The detector chamber can be divided into two. The chopper can be a rotating correlation gas filter. It can have several cells at least one of which contains a gas which absorbs no energy from the radiation passing through it. The system is cheaper to produce and requires less space than previous systems using lasers.