4:00 PM - 6:00 PM
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[21p-P15-10] Development of Cavity Ring-Down Spectroscopy
for Carbon Isotope Analysis of Biomedical Samples (2)
Keywords:laser spectroscopy,radiocarbon,trace analysis
To provide a more compact and cost-effective alternative to Accelerator Mass spectrometry (AMS) for the detection of the radioisotope 14C, we are developing a Cavity Ring-Down Spectrometer for detection of CO2 Drug development, where a high throughput of (14C spiked) medical samples is needed for systematic studies, but sensitivity requirements (1ppb) are relaxed compared to environmental samples (<1ppt) is an ideal target application for such a system.
An overview and status of both our current systems for CRDS of CO2 will be given. Both systems deature a two-mirror high reflectivity Farby-Perot cavity to ensure a very long effective interaction length. The ring-down cavities support the possibility for thermoelectric cooling to suppress interference by absorption of other close-lying molecular transitions. The main difference of the two systems lies in the laser source - whereas the first system features standard telecommunication class DFB diode laser systems at 1.6 um, our new prototype system incorporates a quantum-cascade laser operating at 4.5 um. Due to the higher absorption strength of CO2 in this mid IR region a much higher sensitivity is expected. Furthermore the cavity-design has been reworked for improved mechanical stability.The new prototype has been assembled just very recently, so that only limited performance data is available yet. While not attaining the ultimate in sensitivity the existing 1.6 um system will be further used to explore various schemes in order to minimize statistical and systematic uncertainties such as the option to lock the laser system to a frequency stabilized fiber-comb source.
An overview and status of both our current systems for CRDS of CO2 will be given. Both systems deature a two-mirror high reflectivity Farby-Perot cavity to ensure a very long effective interaction length. The ring-down cavities support the possibility for thermoelectric cooling to suppress interference by absorption of other close-lying molecular transitions. The main difference of the two systems lies in the laser source - whereas the first system features standard telecommunication class DFB diode laser systems at 1.6 um, our new prototype system incorporates a quantum-cascade laser operating at 4.5 um. Due to the higher absorption strength of CO2 in this mid IR region a much higher sensitivity is expected. Furthermore the cavity-design has been reworked for improved mechanical stability.The new prototype has been assembled just very recently, so that only limited performance data is available yet. While not attaining the ultimate in sensitivity the existing 1.6 um system will be further used to explore various schemes in order to minimize statistical and systematic uncertainties such as the option to lock the laser system to a frequency stabilized fiber-comb source.