title: 13CO2/12CO2 isotopic ratio measurements using a difference frequency-based sensor operating at 4.35 micrometers.
abstract: A portable modular gas sensor for measuring the 13C/12C isotopic ratio in CO2 with a precision of 0.8%(+/-1 sigma) was developed for volcanic gas emission studies. This sensor employed a difference frequency generation (DFG)-based spectroscopic source operating at 4.35 micrometers (approximately 2300 cm-1) in combination with a dual-chamber gas absorption cell. Direct absorption spectroscopy using this specially designed cell permitted rapid comparisons of isotopic ratios of a gas sample and a reference standard for appropriately selected CO2 absorption lines. Special attention was given to minimizing undesirable precision degrading effects, in particular temperature and pressure fluctuations.
authors.affiliation: Rice Quantum Institute, Rice University, Houston, TX 77005, USA.
authors.forename: M
authors.initials: M
authors.lastname: Erdelyi
authors.forename: D
authors.initials: D
authors.lastname: Richter
authors.forename: F K
authors.initials: FK
authors.lastname: Tittel
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D002245:Carbon Dioxide / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005740:Gases / Q000032:analysis; D007834:Lasers; D013054:Spectrophotometry, Atomic; D018707:Volcanic Eruptions
chemical_list: D002247:Carbon Isotopes; D005740:Gases; D002245:Carbon Dioxide