Featuring low electrical power and high sensitivity, the LI-COR 7700 CH4 analyzer is designed for extended deployment in remote locations.
LI-COR Biosciences® has developed the LI-7700 open-path CH4 analyzer for measuring methane fluxes over ecosystems. The open-path approach eliminates the need for pumps and tubing, simplifying both deployment of the instrument and interpretation of the results.
The measurement approach is based on Southwest Sciences' award-winning wavelength-modulation spectroscopy (WMS) technology. The current injected into the laser is modulated at about 1 MHz, causing the wavelength to be modulated as well. A multi-pass Herriott cell provides the optical path of about 30 m in a compact, 1/2 m long instrument. The light transmitted through the multipass cell is detected, demodulated, and digitally processed to determine the methane concentration with parts per billion sensitivity. More details are available at the LI-COR web site, www.licor.com.
Development of Southwest Sciences' flux monitoring technology was funded in part by DOE and NOAA through their SBIR programs.