2010 R&D 100 Winner
A potent greenhouse gas, atmospheric methane has become an important target of study. Ecosystem methane flux readings are used by scientists to build climate change models, which are then used to inform policymakers. As a result, a portable methane analyzer that can be used in nearly any environment would be useful.
The LI-7700 Open Path Methane Analyzer from LI-COR Biosciences, Lincoln, Neb., and Southwest Sciences Inc., Santa Fe, N.M., is designed to perform methane density measurements in situ with high resolution using the principle of wavelength modulation spectroscopy (WMS). The 5.2 kg, 10 W device provides frequency response up to 40 Hz and derives its low power usage and light weight from a single-mode tunable near-infrared laser source, operating near ambient temperature.
The LI-7700 measures trace atmospheric methane by projecting a laser beam between two mirrors in an open cavity. This cavity features physical path of 0.5 m from a multi-pass Herriot cell and 30 m optical path. A relatively short optical path of 30 m is made possible by WMS, and allows the instrument to operate with high integrity over a wide range of signal strengths. It achieves a resolution of 5 ppb at 10 Hz.
Technology
Methane analyzer
Developers
LI-COR Biosciences
Southwest Sciences Inc.
Development Team
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| First row, l-r: Douglas Allyn, Bob Eckles, David Franzen, Liukang Xu, George Burba, Tyler Anderson. Second row, l-r: Dave Krenk, Thad Miller, Jerry Ficke, Jess Roe, Jeni VanArsdall, Sharon Bruce, Anatoly Komissarov. Third row, l-r: Bill Mller, Kevin Ediger, Brad Riensche, Dayle McDermitt, Dan Anderson, Michael Sawyer, Jason Hupp.
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LI-7700 Open Path Methane Analyzer Development Team from LI-COR Biosciences
Douglas Allyn
Dan Anderson
Tyler Anderson
George Burba
Bob Eckles
Kevin Ediger
Dave Franzen
Anatoly Komissarov
Dayle McDermitt
Bill Miller
Brad Riensche
Mike Sawyer
Liukang Xu
