PAS Sensor for Vertical Profiling of CO2 in the Atmosphere

79333S Atmospheric researchers need better sensors for the vertical profiling of carbon dioxide (CO2) in the atmosphere. Today, these researchers rely on non-dispersive infrared detectors, which can achieve only limited sensitivity. This project will develop an alternative technique, photoacoustic spectroscopy (PAS), which is better suited for this application. Rather than detecting low-energy photons with detectors susceptible to thermal noise, it detects a pressure signal with a high-sensitivity microphone that is relatively insensitive to thermal perturbations. Phase I will demonstrate a prototype PAS system that can detect 0.25 ppm fluctuations in the CO2 content of air. Commercial Applications and other Benefits as described by the awardee: In addition to the application for terrestrial CO2 sensing, a low¿cost, high-precision (around 1 ppm) CO2 sensor should benefit the food processing, pharmaceutical, and beverage industries., Today, the cost of high-precision sensors limits their use. As sales volumes increase, economies of scale would enable price reductions that would allow this technology to address applications such as capnography (the study of human breath waveforms for medical diagnostics).