| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect easily a very small quantity of oxygen concentration, by setting the ratio of a discharge power to a gas flow rate as a prescribed ratio, and by setting the residence time of nitrogen gas including a very small quantity of oxygen gas as a prescribed time, and be decomposing the gas by discharge plasma, and by measuring the initial oxygen concentration from a produced N2O concentration. SOLUTION: The ratio of a discharge power W to a gas flow rate Q is set as W/Q>100J/N litter, and the residence time tr of nitrogen gas including a very small quantity of oxygen gas is set as tr>2×102(Wp)-0.5 W; making power density (W/cm3), p; gas pressure (atm)}. A very small fixed quantity of gas to be measured is introduced into a discharge reaction part 1 from a main pipe 4 through a gas pump 3a and a mass flow controller 3b. The introduced nitrogen gas including a very small quantity of oxygen gas is converted into N2O having absorptivity relative to infrared light in the discharge reaction part 1, and is subjected to discharge processing, and introduced into a measurement system 2. The concentration of N2O is measured by the system 2 for measuring infrared absorption spectrum, and thereby the oxygen concentration in the gas to be measured is detected.</p> |
