| 摘要 |
<p>PURPOSE:To take a measurement securely by passing measurement light and reference light through gas to be measured without reference to conditions of the temperature, pressure, etc., of the gas to be measured. CONSTITUTION:Light beams from a light source 2 are made parallel and become pulse light beams by passing through a light chopper 5 and the pulse light beams reach a beam splitter 6; and part of it are reflected by the surface of the splitter 6 and enter a photodetector 9. The light beams are converted into an electric signal L1, which is the start intensity signal of the reference light. Light beams transmitted through the splitter 6, on the other hand, are emitted out of a window 17 and absorbed when passing through the gas 18 to be measured, and the light beams are reflected by a retroreflector 19 to reach the reverse surface of the splitter 6 and then reach a beam splitter 10. Part of it are incident on a photodetector 13 and converted into an electric signal L2 which is the end intensity signal of the reference light. Further, light beams passed through the splitter 10 are incident on a photodetector 16 and converted into an electric signal L3 and a lock-in amplifier extracts only a component corresponding to a synchronizing signal of frequency from the chopper 5 to become the end intensity signal of the measurement light. Thus, secure measuring operation is performed.</p> |
