| 摘要 |
PURPOSE: To carry out accurate gas analysis including determination of oxygen concentration for monitoring exhausting gas emission by generating sound waves having an amplitude corresponding to the oxygen concentration in a mixture body and frequency of modulated frequency by absorbing infrared laser radiation in an optoacoustic cell. CONSTITUTION: An optoacoustic cell 1 is operated by introducing object infrared radiation to be modulated as to have frequency which the gas to be measured absorbs into an optoacoustic cell 1 through an infrared ray transmissive window 3. When the infrared radiation is transmitted through a gas containing a gas which absorbs the infrared radiation with the absorbable frequency in the optoacoustic cell 1, a part of the infrared radiation is absorbed in the gas and the temperature is elevated. Consequently, the pressure is increased and sound waves with modulated frequency of the incidence and radiation are generated in the optoacoustic cell 1 by the incidence and radiation and these sound wave are gathered in a microphone 2. The inside of the optoacoustic cell 1 is acoustically insulated from a gas inlet pipe 8 and output pipe 9 by a gas inlet valve 10 and outlet valve 11. |
