Optimization of data retrieval process for spectroscopic CO2 isotopologue ratio measurements. (5th April 2017)

• Record Type: Journal Article
• Authors: Hovorka, J; Čermák, P; Veis, P
• Is Part Of: Laser physics. Volume 27:Number 5(2017:May)
• Publication Date: 2017-04-05
• Subjects: CO2 isotopologues -- laser spectroscopy -- cavity ring down; Lasers -- Periodicals; 621.36605
• DOI: 10.1088/1555-6611/aa64b8
• Languages: English
• ISSNs: 1054-660X

Abstract

Abstract: In this work, a numerical model was developed for critical evaluation of the 13 CO2 / 12 CO2 ratio retrievals ( Δ δ value) from laser absorption spectra. The goal of the analysis was to determine the dependency of the absolute error of δ on different experimental parameters, in order to find the optimal conditions for isotopic ratio retrievals without using calibrated reference samples. In our study, the target precision for Δ δ was set at a level of ⩽ 1 %. The analysis was performed in the spectral range of the ν 1 + ν 3 CO2 band at 1.6 μ m, with the theoretical data originating from the HITRAN database. The proposed fitting algorithm allowed efficient compensation of the interference from weak transitions which are not well recognizable in a single spectrum. This effect was found to make a dominant contribution to the Δ δ value. Next, the optimal conditions for such an experiment regarding the pressure, spectral range and spectrum noise were found and discussed from the perspective of widely tunable laser applications.