Characterization of argon metastable species as function of time, space, and current of a pulsed dc glow discharge

摘要

Optical measurements performed through an iCCD camera equipped with an optical bandpass filter have been carried out on a pulsed dc glow discharge (GD) in order to study the spatial, temporal, and current dependency of the 1s_5 (~3P_2) Ar metastable (Ar*) species. For the spatial and temporal study the pressure was held constant at 1 hPa. The combination of the iCCD camera with the bandpass filter has allowed to acquire time-resolved images of the Ar* in a spatial region between the cathode and the anode. Those measurements have been performed through optical emission and absorption spectroscopy and have shown that the Ar* during the powering phase of the pulsed GD maximize in a spatial region close to the cathode (ca. 1 mm) and that at the end of the pulsed GD, in the so-called afterglow region, the Ar* maximize in a spatial region far from the cathode (between 6-8 mm). Then they reach their maximum intensity within the first 100 us and decay within 200-250 us, both after the end of the GD. It has also been observed that the Ar* species increase by increasing current.