title: Applications of cavity ring-down spectroscopy to high precision isotope ratio measurement of 13C/12C in carbon dioxide.
abstract: Recent measurements of carbon isotopes in carbon dioxide using near-infrared, diode-laser-based cavity ring-down spectroscopy (CRDS) are presented. The CRDS system achieved good precision, often better than 0.2 per thousand, for 4% CO2 concentrations, and also achieved 0.15-0.25 per thousand precision in a 78 min measurement time with cryotrap-based pre-concentration of ambient CO2 concentrations (360 ppmv). These results were obtained with a CRDS system possessing a data rate of 40 ring-downs per second and a loss measurement of 4.0 x 10(-11) cm(-1) Hz(-1/2). Subsequently, the measurement time has been reduced to under 10 min. This standard of performance would enable a variety of high concentration (3-10%) isotopic measurements, such as medical human breath analysis or animal breath experiments. The extension of this ring-down to the 2 microm region would enable isotopic analysis at ambient concentrations, which, combined with the small size, robust design, and potential for frequent measurements at a remote site, make CRDS technology attractive for remote atmospheric measurement applications.
authors.affiliation: Picarro Inc., Sunnyvale, CA 94085, USA.
authors.forename: Ed H
authors.initials: EH
authors.lastname: Wahl
authors.forename: Bernard
authors.initials: B
authors.lastname: Fidric
authors.forename: Chris W
authors.initials: CW
authors.lastname: Rella
authors.forename: Sergei
authors.initials: S
authors.lastname: Koulikov
authors.forename: Boris
authors.initials: B
authors.lastname: Kharlamov
authors.forename: Sze
authors.initials: S
authors.lastname: Tan
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Kachanov
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Richman
authors.forename: Eric R
authors.initials: ER
authors.lastname: Crosson
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Paldus
authors.forename: Shashi
authors.initials: S
authors.lastname: Kalaskar
authors.forename: David R
authors.initials: DR
authors.lastname: Bowling
mesh_terms: D000388:Air / Q000032:analysis*; D002245:Carbon Dioxide / Q000737:chemistry*; D002247:Carbon Isotopes / Q000737:chemistry*; D006801:Humans; D015203:Reproducibility of Results; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation / Q000379:methods
chemical_list: D002247:Carbon Isotopes; D002245:Carbon Dioxide