skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Standoff Detection of Isotopes in a NH3 Chemical Plume


We perform standoff detection of 14NH3 and 15NH3 at a 10 Hz rate in a chemical plume with varying concentration using an external cavity quantum cascade laser swept over the range 930-1065 cm-1.

Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: Conference on Lasers and Electro-Optics (CLEO 2017): Applications and Technology, May 14-19, 2017, San Jose, California, Paper No. AM1A.3
Country of Publication:
United States
(140.3600) Lasers; tunable; (280.3420) Laser; sensors; (300.6340) Spectroscopy

Citation Formats

Phillips, Mark C., and Brumfield, Brian E. Standoff Detection of Isotopes in a NH3 Chemical Plume. United States: N. p., 2017. Web. doi:10.1364/CLEO_AT.2017.AM1A.3.
Phillips, Mark C., & Brumfield, Brian E. Standoff Detection of Isotopes in a NH3 Chemical Plume. United States. doi:10.1364/CLEO_AT.2017.AM1A.3.
Phillips, Mark C., and Brumfield, Brian E. Tue . "Standoff Detection of Isotopes in a NH3 Chemical Plume". United States. doi:10.1364/CLEO_AT.2017.AM1A.3.
title = {Standoff Detection of Isotopes in a NH3 Chemical Plume},
author = {Phillips, Mark C. and Brumfield, Brian E.},
abstractNote = {We perform standoff detection of 14NH3 and 15NH3 at a 10 Hz rate in a chemical plume with varying concentration using an external cavity quantum cascade laser swept over the range 930-1065 cm-1.},
doi = {10.1364/CLEO_AT.2017.AM1A.3},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue May 30 00:00:00 EDT 2017},
month = {Tue May 30 00:00:00 EDT 2017}

Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Pacific Northwest National Laboratory (PNNL) has recently developed a hybrid infrared technique for standoff chemical detection. Active infrared detection typically involves a sender and receiver telescope separated by (100's) of meters and is quite sensitive, but is extremely cumbersome to align and is extremely sensitive to misalignment as the two telescopes must not only be parallel, but coaxial. Passive infrared sensing offers facile alignment (simply point the input optics), but relies on a happenstance temperature difference T between the chemical plume and its background. Often times the T found in the field is only 1 or 2 K, and themore » passive method is thus not very sensitive in many cases. The ''semi-active'' technique creates a large temperature difference T by placing an extended blackbody source at some distance away from the receiver telescope. The blackbody is designed to fill the telescope's FOV at a typical distance of 100 m, and provides a typical temperature difference T on the order of 80 to 100 K. Design considerations and experimental results in a direct comparison of passive, active, and semi-active measurements will be discussed« less
  • The ability to perform not only elementally but also isotopically sensitive detection and analysis at standoff distances is important for remote sensing applications in diverse ares, such as nuclear nonproliferation, environmental monitoring, geophysics, and planetary science. We demonstrate isotopically sensitive real-time standoff detection of uranium by the use of femtosecond filament-induced laser ablation molecular isotopic spectrometry. A uranium oxide molecular emission isotope shift of 0.05 ± 0.007 nm is reported at 593.6 nm. We implement both spectroscopic and acoustic diagnostics to characterize the properties of uranium plasma generated at different filament- uranium interaction points. The resulting uranium oxide emission exhibitsmore » a nearly constant signal-to-background ratio over the length of the filament, unlike the uranium atomic and ionic emission, for which the signal-to-background ratio varies significantly along the filament propagation. This is explained by the different rates of increase of plasma density and uranium oxide density along the filament length resulting from spectral and temporal evolution of the filament along its propagation. Lastly, the results provide a basis for the optimal use of filaments for standoff detection and analysis of uranium isotopes and indicate the potential of the technique for a wider range of remote sensing applications that require isotopic sensitivity.« less
  • No abstract prepared.
  • Pacific Northwest National Laboratory (PNNL) continues to expand its library of quantitative infrared reference spectra for remote sensing. The gas-phase data are recorded at 0.1 cm-1 resolution, with nitrogen pressure broadening to one atmosphere to emulate spectra recorded in the field. It is planned that the PNNL library will consist of approximately 500 vapor-phase spectra associated with DOE’s environmental, energy, and public safety missions. At present, the database is comprised of approximately 300 infrared spectra, many of which represent highly reactive or toxic species. For the 298 K data, each reported spectrum is in fact a composite spectrum generated bymore » a Beer’s law plot (at each wavelength) to typically 12 measured spectra. Recent additions to the database include the vapors of several semi-volatile and non-volatile liquids using an improved dissemination technique for vaporizing the liquid into the nitrogen carrier gas. Experimental and analytical methods are used to remove several known and new artifacts associated with FTIR gas-phase spectroscopy. Details concerning sample preparation and composite spectrum generation are discussed.« less
  • The Pacific Northwest National Laboratory is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff concealed weapon detection. The prototype radar imaging system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. Recent improvements to the system include increased imaging speed using improved balancing techniques, wider bandwidth, and image display techniques.