DEVICE AND METHOD OF TRACE GAS ANALYSIS USING CAVITY RING-DOWN SPECTROSCOPY

摘要

An apparatus and method for analyzing an impurity on a gas is provided. The apparatus includes a first cell (208) containing a first gas with the impurity and a second cell (210) containing a second gas absent the impurity. A first light beam (201a) is coupled into the first cell (208) and a second light beam (201b) is coupled into the second cell (210). A first detector (214) is coupled to an output of the first cell (208) and generates a first signal based on a decay rate of the first light beam within the first cell (208). A second detector (216) is coupled to an output of the second cell (210) and generates a second signal based on a second decay rate of the second light beam within the second cell (210). The concentration of the impurity is determined based on a difference between the first decay rate and the second decay rate.