Determination of Electron Density and Temperature in Atmospheric Helium DBD Plasma by Spectroscopic Diagnostics

Abstract

Summary form only given. Dielectric barrier discharge (DBD) of helium at atmospheric pressure was experimentally investigated. Two parallel-plane electrodes are 50 mm in diameter and each was covered by a quartz plate that is 120mm x 120 mm in size and 1 mm in thickness. In order not only to make optical diagnostics side-on, but also end-on, one electrode was made from ITO (indium tin oxide) film that is transparent to discharge light. The gas gap was kept at 5 mm. The time-resolved and space-resolved spectrum (200 nm -900 nm) from discharge plasma was recorded with a spectrometer (SP-2558 from Acton) coupled to the ICCD camera (PIMAX2 1003RB-FG-43 from Princeton Instruments) using fast gate mode (exposure time down to 10 ns). The electron temperature was determined by using a commonly used method, intensity ratio of two spectral lines. With the determined electron temperature, the electron density was deduced basing on "atomic spectral line free parameter deconvolution procedure" in which Stark broadening of a spectral line was separated from the total broadening.