- Dimensions: 65 cm x 43 cm x 27 cm (core instrument)
- Weight: 25 kg (core instrument)
- Electric Power: 400 W, 120/240 V, 50/60 Hz (core instrument)
- Atmospheric monitoring of isotopic gradients from aircraft and other mobile platforms
- Eddy covariance iso-flux measurements
- Isotopic composition measurements
|Laser Frequency||2310 cm-1||2310cm-1|
RMS noise in ratio
for 1 second data1
|0.1 ‰||0.1 ‰|
|0.03 ‰||0.03 ‰|
Accuracy relative to calibration
|0.1 ‰||0.1 ‰|
|Sampling frequency3||1 Hz to 20 Hz||...|
|Flow cell 1/e time response3||0.05 seconds||...|
1. The RMS noise definition is defined by the 1 sigma standard deviation of a data stream with a 1 Hz sampling frequency for the ratio of the minor isotope to the major isotope. The values given are for simultaneous detection of all three isoptopologues with [CO2] = 380 ppm.
2. The absolute isotopic ratios are based on the periodic addition of calibration gases using automated solenoid valve (included).
3. The sampling frequency of 1 to 20 Hz is the electronic processing speed. The gas exchange time constant (1/e) in the 0.3 liter volume sampling cell is tau=0.05 seconds with a 420 liter-per-minute vacuum pump (optional).
New Method for Isotopic Ratio Measurements of Atmospheric Carbon Dioxide Using a 4.3 micron Pulsed Quantum Cascade Laser, D.D. Nelson, J. B. McManus, S. C. Herndon, M. S. Zahniser, B. Tuzson, L. Emmenegger, Applied Physics B., 90, 301-309, 2008.
Infrared laser spectrometer with balanced absorption for measurements of isotopic ratios of carbon gases, J. B. McManus, M. S. Zahniser, D. D. Nelson, L. R. Williams, C. E. Kolb, Spectrochim. Acta A, 58, 2465-2479, 2002.
A high precision pulsed QCL spectrometer for measurements of stable isotopes of carbon dioxide, J.B. McManus, D. D. Nelson, J. H. Shorter, R. Jiménez, S. Herndon, S. Saleska, M. S. Zahniser, J. Modern Optics, 52, 2309-2321, 2005.
What are the instrumentation requirements for measuring the isotopic composition of net ecosystem exchange of CO2 using eddy covariance methods?, S. R. Saleska, J. Shorter, S. Herndon, R. Jimenéz, B. McManus, D. Nelson, M. S. Zahniser, Isotopes Environ. Health Studies, 42, 115-133, 2006.
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