Two-photon excited LIF determination of H-atom concentrations near a heated filament in a low pressure H(2)environment.
نویسندگان
چکیده
With respect to the investigation of low pressure filament-assisted chemical vapor deposition processes for diamond formation, absolute concentrations of atomic hydrogen were determined by two-photon laserinduced fluorescence in the vicinity of a heated filament in an environment containing H(2) or mixtures of H(2)and CH(4). Radial H concentration profiles were obtained for different pressures and filament temperatures, diameters, and materials. The influence of the addition of various amounts of methane on the H atom concentrations was examined.
منابع مشابه
Nitrogen Atom Detection in Low-Pressure Flames by Two-Photon Laser-Excited Fluorescence
Nitrogen atoms have been detected in stoichiometric flat premixed H2/O2/N2 flames at 33 and 96 mbar doped with small amounts of NH3, HCN, and (CN)2 using two-photon laser excitation at 211 nm and fluorescence detection around 870nm. The shape of the fluorescence intensity profiles versus height above the burner surface is markedly different for the different additives. Using measured quenching ...
متن کاملCharacteristics of the Temporal Behavior of Entanglement between Photonic Binomial Distributions and a Two-Level Atom in a Damping Cavity
In the present study, temporal behavior of entanglement between photonic binomial distributions and a two-level atom in a leaky cavity, in equilibrium with the environment at a temperature T, is studied. In this regard, the master equation is solved in the secular approximation for the density matrix, when the initial photonic distribution is binomial, while the atomic states obey the Boltzmann...
متن کاملتولید دزیمتر LiF: Mg, Ti و مقایسه پاسخ آن با دزیمتر (LiF: Mg, Ti (TLD-100 ساخت شرکت هارشا در برابر پرتوهای گاما
Thermoluminescence dosimeters are small tablets used with 3. 2*3. 2*0. 9mm^3 for measurement of received dose from radioactive various beams. The most common dosimeter is TLD-100 which is lithium-fluoride family and this dosimeter contain magnesium impurities. In this study, first lithium-flouride powder was mixed with titanium and controlled atmosphere samples were heated. After measuring ...
متن کاملAtomic hydrogen concentration profiles at filaments used for chemical vapor deposition of diamond
The quantitative determination of atomic hydrogen concentrations cn in the vicinity of hot filaments is performed with two-photon laser-induced fluorescence. The measurements yield atomic hydrogen concentration profiles up to 28 mm from the filament surface with a spatial resolution of about 0.5 mm. The nonequilibrium nature of the hydrogen dissociation on the filament surface results in a satu...
متن کاملDetermination of acute toxicity and the effects of sub-acute concentrations of CuO nanoparticles on blood parameters in Rutilus rutilus
Objective(s):Copper oxidenanoparticles have different industrial applications so it is inevitable that nanoparticulate products finally find their way into aquatic ecosystems. Nevertheless there is little information available about their effects on some of edible fish. The present study aims to determine the acute toxicity and evaluate the effect of two sub-acute concentrations (50 and 70% 96 ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Applied optics
دوره 29 33 شماره
صفحات -
تاریخ انتشار 1990