High Sensitivity Isotopic Gas Concentration-Ratio Measurement using Isotopic Gas Laser Oscillation

为了高灵敏度地测量痕量混合气体的同位素浓度比，特别是二氧化碳同位素浓度比，我们研制了一<12>套<13>含内腔吸收池的CO_2-CO_2复合激光系统。从理论上分析了腔内吸收池的灵敏度提高幅度，其值约为100。为了估计本系统的最终灵敏度，我们尝试了对<13><12>大气和人工呼吸中的^ CO_2和^ CO_2的检测。<13>用具有腔内吸收池的CO_2激光器对大气和人工大气中的CO_2进行了检测<13>，估计本系统的最低检测浓度为20 ppb。

For high sensitivity measurement of isotopic concentration-ratio of trace-level gas mixture, particularly including carbon dioxide isotopes, we tested a ^<12>CO_2-^<13>CO_2 composite laser system containing intracavity absorption cells. Sensitivity enhancement obtainable by the intracavity absorption cell configuration was examined theoretically and found to be around 100.To estimate the ultimate sensitivity of the present system, we tried to detect ^<13>CO_2 and ^<12>CO_2 in atmospheric air and artificial breath.^<13>CO_2 inclouded in atmospheric air and in the artificial were detected by a ^<13>CO_2 laser having the intracavity absorption cell, minimum detectable concentration by the present system was estimated to be 20ppb.