Dual Laser Quantum Cascade Laser Trace Gas Monitor
Sensitive, rapid, highly specific and continuous measurements of multiple atmospheric trace gases in ambient air.
Applications
- Extremely sensitive detection of a wide variety of atmospheric trace gases, such as: methane, nitrous oxide, nitric oxide, nitrogen dioxide,
carbon monoxide, carbon dioxide, formaldehyde, formic acid, ethylene,
acetylene, carbonyl sulfide, acrolein, ammonia and others. - Combustion monitoring and characterization.
- Isotopic monitoring of CH4 and N2O for source/sink characterization.
- Eddy Covariance measurements.
- Fast response plume studies.
- Air quality monitoring.
- Mobile measurements from ship, truck, and Aircraft platforms.
Advantages
- Absolute trace gas concentrations without calibration gases.
- Fast time response.
- Free from interferences by other atmospheric gases or water vapor.
- Turnkey and unattended operation.
- Cryogen free.
- Ready to be deployed in field measurements and on moving platforms.
- Two lasers allow simultaneous measurement of more species.
- Optical pathlength of either 76 meters or 210 meters.
Summary of detected gases
Extremely high precision and accuracy is obtainable with CW-RT QCLs.
Table 1 Atmospheric trace gases which can be monitored with CW QC lasers. For each species the optimal wavelength (cm-1), the nominal detection precision (ppt in1 sec) and the detection limit (2 sigma in 100 sec) are givenbased upon a sampling cell with pathlength of 210 m.
| Trace gas | Wavenumber [cm-1] | Precision (1 s) [ppt] | LOD (100 s) [ppt] |
| 12CH4 | 1271 | 400 | -- |
| 13CH4 | 1294 | 25 | 10 |
| CO | 2190 | 20 | 10 |
| N2O | 1271 | 80 | -- |
| N2O | 2250 | 30 | -- |
| NH3 | 967 | 12 | 6 |
| NO2 | 1600 | 20 | 10 |
| HONO | 1279 | 150 | 80 |
| HCHO | 1765 | 50 | 20 |
| HCOOH | 1766 | 80 | 40 |
| NO | 1900 | 80 | 40 |
| OCS | 2056 | 6 | 3 |
Data outputs Local storage, internet, RS232, analog output
Sata rate 1 to 10 Hz (depends on specific instrument and vacuum pump)
Instrument operationAutonomous and/or remote control
Options Replacement lasers to access additional molecules
On site training
Mechanical specifications for dual QCL
Dimensions530 mm x 660 mm x 710 mm (W x D x H)
Weight72 kg
Electrical Power500 W, 120/240 V, 50/60 Hz (with Varian IDP-3 vacuum pump)
Multipass cell
Choice of 76 meter standard cell (V=0.5 liters) or 210 meter “Super Cell” (V=2liters)
References
Nelson, D.D. et al., Optics Let. 31, 2012-2014, 2006.
McManus, J.B. et al., Applied Physics B, DOI: 10.1007/s00340-006-2407-7 (2006).
McManus, J.B., M.S. Zahniser, D.D. Nelson, L.R. Williams, and C.E. Kolb, Infrared laser spectrometer with balanced
absorption for measurements of isotopic ratios of carbon gases, Spectrochim. Acta A, 58, 2465-2479, (2002).
McManus, J.B., D.D. Nelson, J.H. Shorter, R. Jiménez, S. Herndon, S. Saleska, and M.S. Zahniser, A high precision pulsed QCL spectrometer for measurements of stable isotopes of carbon dioxide, J. Modern Optics, 52, 2309-2321 (2005).
Saleska, SR; J. Shorter, S. Herndon, R. Jimenéz, B. McManus, D. Nelson, M. Zahniser, What are the instrumentation requirements for measuring the isotopic composition of net ecosystem exchange of CO2 using eddy covariance methods? Isotopes in Environmental and Health Studies, 42 (1), 117 (2006).
Nelson, D.D., J. B. McManus, S. C. Herndon, M. S. Zahniser, B. Tuzson and L. Emmenegger, New Method for Isotopic Ratio Measurements of Atmospheric Carbon Dioxide Using a 4.3 μm Pulsed Quantum Cascade Laser, Appl. Phys. B 90, 301–309 (2008).
Tuzson, B , J. Mohn, M. J. Zeeman, R. A. Werner, W. Eugster, M. S. Zahniser, D. D. Nelson, J. B. McManus, L. Emmenegger, High precision and continuous field measurements of δ13C and δ18O in carbon dioxide with a cryogen-free QCLAS, Appl. Phys. B 92, 451-458 (2008).
For more information or support for our quantum cascade lasers:
qcl-info@aerodyne.com
