| 摘要 |
A photoacoustical gas detector comprises at least one light source transmitting "chopped" light through a room in which a certain gas shall be detected/measured, and further a measurement cell having a window through which the light is passed. The measurement cell contains the same gas (measurement gas) as the one to be detected/measured, and a sound sensor for picking up sound generated in the gas in the cell. In order to compensate for drift due to deposits on windows or due to light source variations, one additional gas is provided inside the cell. This additional gas has an absorption spectrum that is characteristically different from the absorption spectrum of the measurement gas. |
