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Pressure Monitoring Using Hybrid fs/ps Rotational CARSWe investigate the feasibility of gas-phase pressure measurements at kHz-rates using fs/ps rotational CARS. Femtosecond pump and Stokes pulses impulsively prepare a rotational Raman coherence, which is then probed by a high-energy 6-ps pulse introduced at a time delay from the Raman preparation. Rotational CARS spectra were recorded in N2 contained in a room-temperature gas cell for pressures from 0.1 to 3 atm and probe delays ranging from 10-330 ps. Using published self-broadened collisional linewidth data for N2, both the spectrally integrated coherence decay rate and the spectrally resolved decay were investigated as means for detecting pressure. Shot-averaged and single-laser-shot spectra were interrogated for pressure and the accuracy and precision as a function of probe delay and cell pressure are discussed. Single-shot measurement accuracies were within 0.1 to 6.5% when compared to a transducer values, while the precision was generally between 1% and 6% of measured pressure for probe delays of 200 ps or more, and better than 2% as the delay approached 300 ps. A byproduct of the pressure measurement is an independent but simultaneous measurement of the gas temperature.
Document ID
20160006094
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Kearney, Sean P.
(Sandia National Labs. Albuquerque, NM, United States)
Danehy, Paul M.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
May 13, 2016
Publication Date
January 5, 2015
Subject Category
Instrumentation And Photography
Report/Patent Number
NF1676L-20397
Meeting Information
Meeting: AIAA SciTech 2015
Location: Kissimmee, FL
Country: United States
Start Date: January 5, 2015
End Date: January 9, 2015
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 432938.09.01.07.90
CONTRACT_GRANT: DE-AC04-94AL85000
Distribution Limits
Public
Copyright
Public Use Permitted.
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