title: Trace moisture detection using continuous-wave cavity ring-down spectroscopy.
abstract: We have developed an instrument to measure trace concentrations of small hydride species in gases using continuous-wave cavity ring-down spectroscopy with near-infrared diode laser excitation. An rms baseline equivalent absorbance of 9.2 x 10(-11) cm(-1)/square root(n) is found, where n is the number of ring-down transients. When the 1396.376-nm absorption line of water is used, this corresponds to a noise equivalent moisture concentration in nitrogen gas of 68 pptv/square root(n). Water vapor concentration is detected over a range extending from 3 to 1000 ppbv and found to depend linearly on the concentration as determined by a calibrated commercial moisture sensor.
authors: Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
authors: John B
authors: JB
authors: Dudek
authors: Peter B
authors: PB
authors: Tarsa
authors: Armando
authors: A
authors: Velasquez
authors: Mark
authors: M
authors: Wladyslawski
authors: Paul
authors: P
authors: Rabinowitz
authors: Kevin K
authors: KK
authors: Lehmann