Trace-level isotope concentration-ratio measurement 12 CO 2 - 13 CO 2 laser system

Abstract

For high sensitivity measurements of isotope concentration-ratios of trace-level gas mixtures, 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 modulation absorption-cell with synchronous detection scheme was examined theoretically. 13 CO 2 in atmospheric air was readily detected and minimum detectable concentration by the present system was estimated to be 70 ppb.