13:30 〜 13:45
▲ [6p-A414-2] Suppression of etalon effects in Cavity Ring-Down Spectroscopy for 14C Isotope Analysis of Biomedical samples
キーワード：spectroscopy, CRDS, trace analysis
High sensitivity techniques such as Accelerator Mass spectrometry are commonly used for detection of the radioisotope 14C. In the environment, its abundance is typically at the ppt level, however in medical samples, where it is used as tracer isotope to study the metabolism of subjects or other biological processes, the abundance can be significantly higher.
For this purpose we have developed a compact cavity ring-down spectrometer (CRDS) system operating in the mid-infrared wavelength region based on a quantum cascade laser system.
Drifts of the baseline and oscillations due to weak feedback from optical surfaces severely limit the sensitivity of the technique. Stabilizing environmental conditions, minimizing the number of optical elements in the laser path or tilting them with respect to the optical axis reduces these effects, but does not eliminate them reliably. Two alternatives were tested – saturated absorption cavity ring-down (SCAR) as well as modulating the path-length between the cavity and external surfaces by varying the temperature of the system.
For this purpose we have developed a compact cavity ring-down spectrometer (CRDS) system operating in the mid-infrared wavelength region based on a quantum cascade laser system.
Drifts of the baseline and oscillations due to weak feedback from optical surfaces severely limit the sensitivity of the technique. Stabilizing environmental conditions, minimizing the number of optical elements in the laser path or tilting them with respect to the optical axis reduces these effects, but does not eliminate them reliably. Two alternatives were tested – saturated absorption cavity ring-down (SCAR) as well as modulating the path-length between the cavity and external surfaces by varying the temperature of the system.