Glow Characterization in Low-Pressure Radio-Frequency $\hbox{CH}_{2} \hbox{F}_{2}$ and $\hbox{C}_{2}\hbox{H}_{2}\hbox{F}_{4}$  Plasma Deposition Systems
The glow characteristics and deposited film structures of fluorocarbon monomers in radio-frequency glow discharges are investigated using CH<sub>2</sub>F<sub>2</sub> and C<sub>2</sub>H<sub>2</sub>F<sub>4</sub>, which were compared to hydrocarbon monomer such as CH<sub>4</sub>. The glow was characterized and investigated by optical photography, optical emission spectroscopy, and Fourier transform infrared spectrometry. The glow differences were attributed to the nature of the luminous gas phase in respect to polymer-forming species.
Deposition behavior in a low-temperature cascade arc torch (CAT) polymerization process
Two kinds of hydrocarbon type monomers and three kinds of organosilicons were polymerized by a low-temperature cascade arc argon plasma torch. Their deposition behaviors were studied as a function of experimental parameters and monomer elemental compositions. It was found that the normalized deposition rate (DR), expressed as deposition yield of DR/(FM) was determined by a composite operational parameter, W * (FM) c /(FM) where W is the power input, and (FM) c and (FM) m are the mass flow rates of carrier gases and monomers, respectively. Experimental results indicated that the deposition yield is highly dependent on the elementary compositions of monomers. Optical emission spectroscopy study on the argon plasma torch showed that the emission intensity of excited argon neutrals was proportional to the value of the parameter W * (FM) c . These results further certified that excited argon neutrals are the main energy carriers from the cascade arc column to activate monomers in the argon plasma torch.
An analytical approach to the design of electrodes in high-power, fast-transverse-flow CO2 lasers
Abstract Usually, the design of the electrodes of fast-transverse-flow CO 2 lasers relies more on experimental data than on theoretical analysis. Traditional systems sustain a stable, high-power discharge but the current distribution generates a peaked, non-uniform small-signal-gain pattern. We present a theoretical model suitable for the design of electrodes that achieves a quasi uniform gain distribution. The analysis, based on a two-temperature model and the gas-transport equations, computes the electron density that supports a flat gain pattern. Combining the desired electron density with the electron-balance equations, the model determines the required electric field. The results were used to design a new set of electrodes for a home-made fast transverse flow CO 2 laser. A stable, large volume discharge ( 4 × 8 × 90 cm 3 ) with very good uniformity was obtained. The resulting gain distribution was registered in a bi-dimensional map. The peak gain rose from 1.2 m - 1 , attained with the old electrode set, to 1.6 m - 1 with the new one and the gain showed a homogeneous profile.