New high-pressure diagnostic technique. Final technical report, 1 August 1993-31 July 1996

Technical Report · Mon Oct 21 04:00:00 EDT 1996

OSTI ID:445808

Zhare, R N

The authors research goal was to develop nonintrusive, laser-based optical diagnostic tools for the investigation of trace amounts of molecular species in hostile environments such as plasmas, flashes, flames and other combustion forms. By extending their study on spectroscopic applications of degenerate four-wave mixing (DFWM), they proposed to exploit a new absorption technique, Cavity Ring-Down Spectroscopy (CRDS), which is, in many ways, complementary to other methods for the investigation of the transient species, radicals, and ions present in harsh luminous environments. A spatial profile of CH3 absolute concentration near the hot filament was determined by CRDS using a topological method - Abel inversion of the spatial profile of CH3 absorbance. No rotational lines are resolved from CH3 because of predissociation. A two-photon laser-induced fluorescence (LIF) scheme is proposed to measure atomic hydrogen. The spatial temperature profile near the filament at 20 Torr of pure H2 at different filament temperatures was measured in the same reactor used to measured CH3. This measurement, combined with the CH3 spatial profile gives a better understanding of the two most important gas phase radical species in the hot-filament diamond CVD process.

• Research Organization: Stanford Univ., CA (United States). Dept. of Chemistry
• OSTI ID: 445808
• Report Number(s): AD-A--318479/3/XAB; CNN: Contract F49620-93-I-0442
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
DIAGNOSTIC TECHNIQUES
FLAMES
HYDROGEN
METHYL RADICALS
OPTICAL SYSTEMS
PLASMA
PROGRESS REPORT
SPATIAL DISTRIBUTION
TRANSIENTS