Patent ID: 8654334
Filing Date: 2014-02-18
Classification: G01N

Abstract:
1. A method of measuring a concentration of a specified gas species within a gaseous sample, comprising: inputting a gaseous sample into an optical cavity; directing pulses of incoherent light of a specified wavelength band off-axis into the optical cavity, the wavelength band of the incoherent light coinciding with an absorption band of a gas species to be measured; detecting an intensity of light output from the optical cavity and measuring a decay time of that intensity, the decay time corresponding to a concentration of the gas species in the gaseous sample; and periodically scrubbing the gaseous sample to remove any of the specified gas species from the sample and inputting the scrubbed sample into the optical cavity, a decay time of the intensity of light output from the cavity with the scrubbed gas forming a calibration reference for determining the concentration of the gas species in the gaseous sample.