稳定同位素观测技术的最新进展.PDF

稳定同位素观测技术的最新进展 Franklin Li May 22nd and 23rd, Beijing Table of Contents Other Laser Trace-Gas Analyzers TGA history and introduction TGA200A’s Specifications TGA200A’s Benefits and Features Case Study Other Laser Trace-Gas Spectroscopy Technologies OA-ICOS, CRDS, WMS Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) - Los Gatos Cavity Ring Down Spectroscopy (CRDS) - Picarro Both manufactures developed a variety of trace-gas analyzers, for multi species w/ CO2, H2O, CH4, …, NH3, or Isotopes An example CRDS or ICOS setup - Multi kilometer optical path length Cavity Ring Down Build up - Beam injected into optical cavity l a n Ring down - Laser is pulsed off and g i signal decays (shaded in blue) S The ring down time is contingent on the concentration of the target species in the optical cavity and the mirror reflectivity. Time Laser on Laser off 1 Sweep? 1 Sweep? CRDS l a n Ring down Pulsed laser g i S Build up t n e May sweep r r u laser or jump C r