Signal detection efficiency in multiphoton ionization flame measurements

Journal Article · Tue Nov 20 04:00:00 EST 1990 · Applied Optics; (USA)

DOI:https://doi.org/10.1364/AO.29.004891· OSTI ID:5936047

Smyth, K C ^[1]; Tjossem, P J.H. ^[2]

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1. U.S. National Institute of Standards Technology, Center for Fire Research, Gaithersburg, Maryland (USA)
2. Grinnell College, Physics Department, Grinnell, Iowa (USA)

Multiphoton ionization is often the most sensitive method available for detecting radical species in flame environments. To make accurate relative concentration measurements, however, the electron (or ion) detection efficiency as a function of flame position must be known. Two methods are presented for determining this quantity in a laminar CH{sub 4}/air diffusion flame burning at atmospheric pressure: (1) simultaneous detection of ionization and fluorescence in CO, following two-photon excitation of the {ital B}{sup 1}{sigma}{sup +} state at 230.0 nm; (2) comparison of 3+1 multiphoton ionization of the 4{ital s}{prime} state of argon at 314.4 nm with mass spectrometric measurements. The results show significant variation of the electron detection efficiency in the lean, stoichiometric, and rich flame regions, with the greatest detection sensitivity observed in the high-temperature, primary reaction zones (i.e., near stoichiometric conditions). Corrections to multiphoton ionization data obtained for H atoms are discussed in terms of determining relative concentration profiles across the methane/air diffusion flame. {copyright} 1990 Optical Society of America

• OSTI ID: 5936047
• Journal Information: Applied Optics; (USA), Journal Name: Applied Optics; (USA) Vol. 29:33; ISSN 0003-6935; ISSN APOPA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ABSORPTION SPECTROSCOPY
ALKANES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
COMBUSTION
COMBUSTION PRODUCTS
ELECTROMAGNETIC RADIATION
FLAMES
HYDROCARBONS
IONIZATION
LASER RADIATION
METHANE
MULTI-PHOTON PROCESSES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHOTOIONIZATION
QUANTITY RATIO
RADIATIONS
RADICALS
SPECTROSCOPY
THERMOCHEMICAL PROCESSES