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High-Performance Fourier Transform Infrared Spectrometer:

High-Performance Fourier Transform Infrared Spectrometer: A Versatile Modular Interdisciplinary Instrument in the Regional Atmospheric Profiling Center for Discovery David A. Bowdle University of Alabama in Huntsville NASA/UAH Atmospheric Science "Brown Bag" Seminar December 4, 2002. A m OR.

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High-Performance Fourier Transform Infrared Spectrometer:

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  1. High-Performance Fourier Transform Infrared Spectrometer: A Versatile Modular Interdisciplinary Instrument in the Regional Atmospheric Profiling Center for Discovery David A. Bowdle University of Alabama in Huntsville NASA/UAH Atmospheric Science "Brown Bag" Seminar December 4, 2002

  2. AmOR OUTLINE • FTIR Theory • FTIR Instrument • Optical Layout • Basic Capabilities • FTIR Science • Planned Use in RAPCD • Potential Interdisciplinary Projects • Brain-storming

  3. Gain, Spectral Resolution, Intergration Time Photo- counts Source Radiance Receiver Area and Solid Angle Optical Efficiency Transmission Extinction Units Instrument Artifacts In situ Mass Extinction Efficiency Correction Reduce By Design Optical Distortion Effective Length Concentration AmOR FTIR THEORY Let spectrum 1 represent a gas sample or a suspended aerosol in the atmosphere or in a laboratory chamber, or an aerosol deposit on a substrate. Let spectrum 0 represent a blank.

  4. NICOLET NEXUS 870 FTIR – EXTERNAL VIEW Interferometer Compartment External Experiment Data Interface Dual Source Compartment Dual Detector Compartment Main Sample Compartment Left External Beam Port AmOR

  5. NICOLET NEXUS 870 FTIR – INTERNAL VIEW Michelson Interferometer) Power Supply Signal Processor Data & Purge Ports DTGS Detector (MIR) Internal Source Compartment InGaAs Detector (NIR) Main Sample Compartment (KBr Windows) Motorized Path Selection Mirrors AmOR

  6. NICOLET NEXUS 870 FTIR – TOP VIEW Motorized Collimating Mirror HeNe Laser Michelson Interferometer) Motorized Aperture Wheel Condensing Mirror (Sample) Condensing Mirror (Source) Globar Source (MIR) Incandescent Source (VIS/NIR) AmOR

  7. NICOLET NEXUS 870 FTIR – OPTICAL PATH External Source Beam Left External Beam Left External Beam AmOR

  8. NICOLET NEXUS 870 FTIR – INTERFEROMETER Piezo-Electric Dynamic Alignment HeNe Laser Fixed Mirror Laser Pickoff Mirror KBr Beam Splitter Extended Range Moving Mirror Drive Dynamic Alignment Phase Detectors AmOR

  9. AmOR NICOLET FTIR CAPABILITIES • Linear scan • Scan speeds up to ~50 Hz • Spectral resolution as fine as ~0.125 cm-1 • Spectral range from 375-11,000 cm-1 • Automated experiment setup including alignment; recognition of key components and accessories; selection of source, detector, and sample chamber; diagnostics; etc. • Easily adaptable to custom attachments • Step scan • Amplitude modulation • Chopper, with lock-in-amplifier • Repeatable sample phenomena • Slow (ms) to ultra-fast (ms) processes • Phase modulation • Dithering of fixed mirror • Analysis of thin layers

  10. AmOR FTIR OPERATION Attend demonstration of Nicolet Nexus 870 FTIR in NSSTC Room 2014 after presentation and brainstorming session

  11. NICOLET NEXUS FTIR - REMOTE SENSING STATION HEPA Filters Solar Tracker Chimney Dimming Incandescents Horizon Scanner Chimney Utility Buss Bar 110, 208 1/Ph, 2083/Ph Air, Vacuum, Nitrogen Data Ports, Light Switch Optical Curtains Optical Bench Cooling Water & Drain Not Shown: Dimming Fluorescents Casework AmOR

  12. AEROSOL mICROPHYSICS AND RADIOMETRY LAB AmOR

  13. AEROSOL mICROPHYSICS AND RADIOMETRY LAB AmOR

  14. RAPCD CHIMNEY INSPECTION Jay Leko interviews for a RAPCD research position Mike Newchurch goes to great lengths to make sure RAPCD works AmOR

  15. AmOR PLANNED USE IN RAPCD • Composition and Concentration of Particles and Trace Gases • Atmospheric Chemistry Measurements • Column optical depth, using multi-spectral Langley plots from a roof-mounted solar tracker with dithered pointing • Horizontal optical thickness, using one-way or two-way transmission with a roof-mounted alt-azimuth scanner • Cloud initiation, cloud particle phase, fog chemistry • Aspirated sample analysis, using bottles, filters, impactors • Size-dependent composition of airborne mineral dust • Deployment in RAPCD mobile van

  16. AmOR PLANNED USE IN RAPCD • Composition and Concentration of Particles and Trace Gases • Atmospheric Chemistry Simulations • Artificial aerosols suspended in air, deposited on substrates • Heterogeneous chemical reactions, chemical kinetics • Calibration/Validation of Atmospheric Sensors and Models • Backscatter enhancement spectra from particle coatings • Composition of calibration particles for lidar backscatter • Optical distortion in particulate deposits on substrates • Scattering from non-spherical particles (e.g., pollen grains) • Polarimetry in transmission, forward scatter, backscatter

  17. AmOR INTERDISCIPLINARY PROJECTS • Satellite remote sensing validation • Precipitation chemistry (remote or aspirated) • Spectral backscatter from simulated river surfaces • Optical emissions and chemical byproducts of lightning • Spectroscopy of simulated interstellar dust grains • Solar spectroscopy and solar variability • Nano-technology, bioaerosol detection • Brief brain-storming session after seminar dismisses

  18. AmOR SUMMARY AND CONCLUSIONS • New high-performance FTIR obtained for RAPCD • Provides versatile tool for atmospheric chemistry research, in both ambient and simulated environments • Initial installation in RAPCD aerosol lab expected in January. Rooftop scanners to be acquired in future proposals. • Offers opportunity for interdisciplinary research ventures by adding modular commercial or in-house accessories

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