A swept-wavelength external cavity quantum cascade laser is used to measure time-resolved 15NH3 and 14NH3 concentrations and isotope ratios in a turbulent plume source located at 10 m standoff distance. Measurements show excellent agreement with expected values of isotope ratios for samples with natural and enriched 15N abundance. Detection sensitivity of 150 ppb*m is demonstrated for a 50 ms measurement interval, improving to 10 ppb*m with 10 s averaging, with isotopic precision as good as 0.8%.
Revised: January 29, 2021 |
Published: September 1, 2018
Citation
Phillips M.C., B.E. Brumfield, and S.S. Harilal. 2018.Real-time standoff detection of nitrogen isotopes in ammonia plumes using a swept external cavity quantum cascade laser.Optics Letters 43, no. 17:4065.PNNL-SA-135139.doi:10.1364/OL.43.004065