An instrumental method for the determination of corona characteristics in accurately-defined media

In our laboratories, an instrumental method has been developed for the characterization of corona discharges in well-defined media under the conditions of extreme purity and reproducibility. An instrument has been developed, consisting of a stainless steel chamber that contains a corona generator, an induction mixing chamber with a manifold in which the medium of well-defined concentration is prepared, and a vacuum and baking system, used to remove the corona medium and by-products. Our instrument performed well in measurements of a number of gases, ranging from pure nitrogen to various chlorinated and fluorinated hydrocarbons. In most of these measurements, corona characteristics were determined with safety and reproducibility. However, the system is suitable not only for the measurements of corona discharges, but also for other measurements, performed under extreme purity in common gases, and for work with aggressive, explosive, or toxic media, that often exhibit surface contamination phenomena. The system operated reproducibly with sample concentrations from 0.1 to 10000 parts per million by volume. In order to reach the 0.1 and 1 ppm levels, the additives were premixed, when possible in 1 to 10 or 1 to 100 dilutions