Rapid-swept CW cavity ring-down laser spectroscopy for carbon isotope analysis

Abstract

With the aim of developing a portable system for an in field isotope analysis, we investigate an isotope analysis based on rapid-swept CW cavity ring-down laser spectroscopy, in which the concentration of a chemical species is derived from its photo absorbance. Such a system can identify the isotopomer and still be constructed as a quite compact system. We have made some basic experimental measurements of the overtone absorption lines of carbon dioxide (12C16O2, 13C16O 2) by rapid-swept cavity ring-down spectroscopy with a CW infrared diode laser at 6,200 cm-1 (1.6 μm). The isotopic ratio has been obtained as (1.07±0.13)×10-2, in good agreement with the natural abundance within experimental uncertainty. The detection sensitivity in absorbance has been estimated to be 3 × 10-8 cm-1. © Atomic Energy Society of Japan.