Plasma diagnostics with semiconductor lasers using fluorescence and absorption spectroscopy
Plasma diagnostics based on fluorescence and absorption spectroscopy using narrow-bandwidth semiconductor lasers have been developed in a 1-kW atmospheric-pressure inductively coupled plasma torch. Measurements of species and electron number density, atom (T) and electron (T[sub e]) kinetic temperature, population temperature (T[sub pop]), and ionization temperature (Ti) were inferred from Stark-affected argon lineshapes recorded in the analytical region of the flowfield. Measurements of saturation intensity and nonradiative collisional transfer (quench) rate were inferred from characteristic variations of partially saturated lineshapes with laser intensity. The transitions investigated, 4s[sup 3]P[sub 2] [r arrow] 4p[sup 3]D[sub 3] (8115 [angstrom]), 4s[sup 3]P[sub 1] - 4p[sup 3]D[sub 1] (8104[angstrom]), 4s[sup 3]P[sub 1] [r arrow] 4p[sup 3]D[sub 2] (8425 [angstrom]), 4s[sup 3]P[sub 0] [r arrow] 4p[sup 1]P[sub 1] (7948 [angstrom]), and 4s[sup 1]P[sub 1] [r arrow] 4p[sup 3]P[sub 1] (8625[angstrom]), included each of the states in the argon 4s configuration. The agreement between atom and electron kinetic temperatures, inferred from the Doppler-broadening lineshape component and the Stark width/shift ratio, suggests that all species are in translational equilibrium. Electron number density values are significantly higher than calculated Saha-equilibrium values at the kinetic temperature. Saturation intensity values were inferred from variations in the linecenter, linewidth, and integrated lineshape values of partially saturated profiles with laser intensity. Quench rates were in good agreement with calculated values of collisional transfer rate. Emission diagnostics enabled a determination of the excitation temperature (T[sub ex]), population and ionization temperatures. The results from the laser and emission diagnostics were consistent and suggested that upper-state argon populations may be described by a Boltzmann distribution at the kinetic temperature.
- Research Organization:
- Stanford Univ., CA (United States)
- OSTI ID:
- 6922080
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ABSORPTION SPECTROSCOPY
ENERGY-LEVEL TRANSITIONS
FLUORESCENCE SPECTROSCOPY
LINE BROADENING
PLASMA DIAGNOSTICS
SEMICONDUCTOR LASERS
STARK EFFECT
ELEMENTS
EMISSION SPECTROSCOPY
FLUIDS
GASES
LASERS
NONMETALS
RARE GASES
SEMICONDUCTOR DEVICES
SOLID STATE LASERS
SPECTROSCOPY
700320* - Plasma Diagnostic Techniques & Instrumentation- (1992-)
664200 - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)