Infrared signatures for remote sensing
PNL`s capabilities for infrared and near-infrared spectroscopy include tunable-diode-laser (TDL) systems covering 300--3,000 cm{sup {minus}1} at <10-MHz bandwidth; a Bruker Fourier-transform infrared (FTIR) spectrometer for the near- to far-infrared at 50-MHz resolution; and a stable line-tunable, 12-w cw CO{sub 2} laser. PNL also has a beam expansion source with a 12-cm slit, which provides a 3-m effective path for gases at {approximately}10 K, giving a Doppler width of typically 10 MHz; and long-path static gas cells (to 100 m). In applying this equipment to signatures work, the authors emphasize the importance of high spectral resolution for detecting and identifying atmospheric interferences; for identifying the optimum analytical frequencies; for deriving, by spectroscopic analysis, the molecular parameters needed for modeling; and for obtaining data on species and/or bands that are not in existing databases. As an example of such spectroscopy, the authors have assigned and analyzed the C-Cl stretching region of CCl{sub 4} at 770--800 cm{sup {minus}1}. This is an important potential signature species whose IR absorption has remained puzzling because of the natural isotopic mix, extensive hot-band structure, and a Fermi resonance involving a nearby combination band. Instrument development projects include the IR sniffer, a small high-sensitivity, high-discrimination (Doppler-limited) device for fence-line or downwind monitoring that is effective even in regions of atmospheric absorption; preliminary work has achieved sensitivities at the low-ppb level. Other work covers trace species detection with TDLs, and FM-modulated CO{sub 2} laser LIDAR. The authors are planning a field experiment to interrogate the Hanford tank farm for signature species from Rattlesnake Mountain, a standoff of ca. 15 km, to be accompanied by simultaneous ground-truthing at the tanks.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 10161758
- Report Number(s):
- PNL-SA--24200; CONF-9404162--8; ON: DE94014222
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quick scanning TDL spectrometry for atmospheric trace gas monitoring with anti-scintillation performance
High-resolution laser absorption spectroscopy of ozone near 1129. 4 cm (-1). Final report, 25 October 1979 - 24 October 1981
Related Subjects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
54 ENVIRONMENTAL SCIENCES
540120
ABSORPTION SPECTROSCOPY
AIR POLLUTION MONITORING
CARBON TETRACHLORIDE
CHEMICAL AND THERMAL EFFLUENTS
CHEMICALS MONITORING AND TRANSPORT
CHLOROFLUOROCARBONS
EXPERIMENTAL DATA
FIELD TESTS
HANFORD RESERVATION
INFRARED RADIATION
METHYLENE CHLORIDE
NEAR INFRARED RADIATION
OPTICAL RADAR
STORAGE FACILITIES
TECHNOLOGY ASSESSMENT