Aerodyne Research, Inc.
 Compact Quantum Cascade Laser Trace Gas Detector
 
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Gas analysis system for continuous accurate measurement of
concentrations and fluxes of atmospheric trace gases.

APPLICATIONS:

  • Infrared absorption measurement of trace gases such as: CH4, N2O, CH2O, CO2, NO, NO2, C2H6, NH3, O3, SO2, H2O2, and HNO3.
  • Atmospheric monitoring or research requiring an instrument flexible and rugged enough to operate unattended in field experiments.
  • Measurement of sources of radiatively important trace species (RITS); aerosol precursors; acid gas deposition rates; air pollution characterization.
  • Remote monitoring of gas phase pollutants near highways, landfills, and hazardous waste disposal sites.
  • Fence-line monitoring around industrial sites.
  • Airborne and/or van-mounted measurements for wide area surveys.
  • Breath analysis for diagnosis or monitoring of disease.

ADVANTAGES:

  • Totally non-cryogenic laser system.

  • Both the Quantum Cascade (QC) laser and  the infrared detector are thermoelectrically cooled.

  • Electronics and optics in a single, compact unit.

  • High Resolution Tunable Infrared Laser Differential Absorption Spectroscopy (TILDAS) provides accurate trace gas concentrations without calibration gases and is free from interferences from other atmospheric species.

  • Novel multipass absorption cell with astigmatic mirrors providing long path length (76 meters) in small volume (0.5 l).

  • Real-time data collection and analysis: sampling frequency of 1 to 20 Hz (electronic processing speed). The gas exchange time constant (1/e) in 0.5 liter volume sampling cell is τ = 0.07 sec with vacuum pump of 500 l/min.

  • QC lasers have excellent mode stability and reproducibility.

  • Continuous, unattended operation.

  • QC laser system is available with either pulsed or newly available continuous wave (cw) room temperature QC lasers. Cw-RT QC lasers have high power, are single mode and have extremely narrow linewidth (<0.0001 cm-1).

    •  

    Diagram of the optical module design of Cryogen-Free Compact QCL-TILDAS-76 Ambient Air Monitor.

    Technical Specifications

      CH4 N2O N2O NH3
    Laser Frequency 1271 cm-1 1271 cm-1 2240 cm-1 967 cm-1
    RMS noise with TE-cooled detector1 2 ppb 0.9 ppb 0.3 ppb 0.3 ppb (1 s)
    0.1 ppb (30 s)
    Relative accuracy <1% (linearity) … … …
    Absolute accuracy2 with calibration gas

    Without calibration

    		 <1% of ambient


    <10% of ambient

    		 … … …
    Sampling frequency3 1 Hz to 20 Hz ... … …
    Flow cell 1/e time response3 0.07 seconds … … …
    Measurement Range 0.5 to 20,000 ppb … … …
    Maintenance Interval 4 weeks      

    1. The RMS noise definition is defined by the 1 sigma standard deviation of a data stream with a 1 Hz sampling frequency.  Our RMS specification for CH4 is 2 ppb Hz-1/2.  By this definition, the RMS at 10 Hz would be 6 ppb.

    2. The absolute concentrations are based on the spectroscopic retrieval of the absorption area combined with the measured pressure, temperature and path length of the absorption cell and the laser spectral line width. The absolute accuracy without calibration is better than 10% of the ambient value. Accuracy may be improved to better than 1% by software-controlled automatic periodic additions of user-supplied calibration gas.

    3. The sampling frequency of 1 to 20 Hz is the electronic processing speed.  The gas exchange time constant (1/e) in the 0.5 liter volume sampling cell is tau=0.07 seconds with the vacuum pump of 500 liters/min (VARIAN TRISCROLL 600). 

    INSTRUMENT SIZE AND WEIGHT

    17"(W) x 24"(D) x 10.5"(H).
    Rack mountable Box
    Weight: 25 kg
    Electrical Power 300 Watts (excluding vacuum pump)

    EPA Environmental Technology Verification  

    An earlier version of the ARI QC-TILDAS instrument was verified in the EPA-ETV program for ambient ammonia monitoring.

    July 2004 - The Aerodyne Research QC-TILDAS Ammonia Monitor is EPA/ETV verified for ambient ammonia monitoring.  The results of the verification test of the EPA Environmental Technology Verification Program (ETV) for the instrument are summarized in the Verification Statement.  A complete description of the technology, verification method and procedures, and detailed results of the test on the Aerodyne Research QC-TILDAS Ammonia Monitor are given in the verification report .

    For more information about this product or associated R&D service contact:  

    Dr. Mark Zahniser
    Vice President
    Director, Center for Atmospheric and Environmental Chemistry

    Phone: 978-663-9500, Ext. 224
    Fax: 978-663-4918
    E-mail: mz@aerodyne.com

     

    Mr. James Akimchuk, Manager of Adminstration

    Phone: 978-663-9500, Ext. 214
    Fax: 978-663-4918
    E-mail: jima@aerodyne.com

          		 

    Aerodyne Research, Inc.  45 Manning Road Billerica, MA  01821-3976  978 663-9500