Observation of Atomic Emission Image from Spark Discharge Plasma by Using Two-dimensional Spectrograph

In order to obtain detailed information on the excitation process which takes place in a spark discharge (SD) plasma, a two dimensional image of atomic emission was observed by using an imaging spectrograph equipped with a charge-couple device (CCD) detector. The emission image of copper emission (Cu I 324.75 nm) emitted from a SD plasma region induced in argon at a low pressure has been successfully observed. It indicates that the copper emission is the most intense at plasma zones being 1.5-2.0-mm apart from the sample surface and becomes weaker at larger distance from the central zone of the SD plasma region, and that the emission image changes with time; where the optimal condition of the emission image is obtained at a delay time of 40 mu s. These results could be valuable information in order to have better understanding about the complicated spectrochemical phenomena occurring in the SD plasma.