Optical characteristics of a gas discharge in mixtures of sulfur vapor with inert gases

The discharge in mixtures of inert gas with sulfur vapors is an effective source of radiation spectrum, which is similar to solar in the wavelength range of 280-600 nm due to strong emission of S2 molecules. This paper presents optical properties of the pulsed-periodic discharge (the pulse $\le $10 kV with duration of several $\mu $s and repetition frequency of 10 kHz) in mixtures of argon with sulfur vapour in the wavelength range of 300-700 nm. In this wavelength range strong bands of S2 molecules are observed in the discharge radiation along with Ar and S lines. Radiation of S2 bands dominates at argon pressure less than 30 Torr. The radiation efficiency of sulfur dimer bands rises with increase in temperature of gas-discharge tube walls. Kinetics of excited sulfur molecules in the discharge is studied using a global model. Time profiles of plasma species densities under various Ar-S2 mixture compositions during voltage pulses were calculated. It is shown, that densities of S2 excited molecules fast increases at the voltage pulse beginning and reach maximum after about 2 $\mu $s, strong radiation of S2 excited molecules is characteristic for this time.