Laser-induced fluorescence study of discharge plasma in He+Xe mixture gas

Abstract

This paper contains experimental results on the population of the 21S atom of HeI in the discharge plasma of a He+Xe gas mixture. The population measurement was made by the laser-induced fluorescence method with the laser light tuned to the HeI line of 5016 A(21S-31P). The fluorescence intensity of HeI lines was measured as a function of the mixture ratio of Xe to He gas. As the Xe gas was mixed, the fluorescence intensity was significantly reduced at pressures ranging from 0.2 to 1 Torr. Further, an increment of the discharge current made the population of the 21S atom increase more remarkably in the Xe-mixed gas than in the pure He. These behaviors were considered using the measured temperature and density of the electrons, and it was concluded that at 1-Torr the Penning collision of the 21S atom with Xe was effective and dominated the behavior of the 21S atom.