Lightweight Balloon-Borne Atmospheric Carbon Dioxide Sensor

The measurement of atmospheric carbon dioxide on expendable balloonsondes , a critical component of the DOE¿s greenhouse gas measurement strategy, is a challenge to optical detection methods. For this application, high sensitivity, precision, and selectivity are required in a rugged, compact lightweight package. In this project, an emerging lightweight photoacoustic spectrometer, initially developed for use with laser diodes, instead will be coupled with an inexpensive infrared light emitting diode (LED) to provide exceptional sensitivity and selectivity to the measurement of atmospheric carbon dioxide. The technique will provide the required precision in a package that meets the demanding physical and cost requirements of expendable balloonsonde flights. In Phase I, a bench top, LED-photoacoustic spectrometer, operating in the mid-infrared region, will be designed and built. The sensor specificity and sensitivity for carbon dioxide will be determined. The ability of the sensor to return the required precision throughout a typical balloon flight will be investigated. The low power draw and light weight of the spectrometer not only will be compatible with ballonsondes but also will provide sub-parts-per-million measurement precision of atmospheric carbon dioxide. Commercial Applications And Other Benefits as described by the Applicant: In addition to the application of carbon dioxide measurement via balloonsondes, the technology should have application to the detection of various trace species. Related instruments at a compelling price could be developed for applications in biomedical breath diagnostics, process gas analysis, occupational safety, and homeland security.