High power VUV and UV excilamps

Summary form only given: In the present paper, the review of the basic results obtained at the Laboratory of Optical Radiation at High Current Electronics Institute SB RAS during 2007-2008 years is presented. Efficient radiation of Ar₂, Kr₂, Xe₂, KrBr*, KrCl*, Xel*, XeBr*, XeCl*, Cl₂* molecules and I atoms was obtained in rare gas or in rare gas- Br₂ (Cl₂,I₂) mixtures. Study of radiation parameters and lifetime period of the manufactured barrier discharge excilamp has been performed. Average power of radiation for the just sealed off KrCl (lambda~222 nm) excilamp exceeded 100 W was obtained. UV output power of ~75 W and efficiency of 10 %, respectively, at lambda~308 nm (XeCl* excilamp) were obtained under excitation by pulses with frequency of 100 kHz. The lifetime of gas mixture in small XeCl* barrier discharge excilamps over 3000 hours was demonstrated. VUV output power of ~120 W at lambda~172 nm was obtained under excitation by pulses with frequency of ~100 kHz. Dynamics of discharge formation in KrCl excilamp has been studied. It has been shown that transition to stationary stage of discharge (in the form of separate microdischarges consisting from two cones with connected tops) takes place within one second as four stages with different discharge forms. Before formation of the stationary fourth stage of discharge, which has the highest efficiency of radiation, the spark stage of discharge is registered during which the bright branchy channels (sparks) are observed. It is supposed that discharge transition from spark to diffuse discharge is determined by formation of runaway electrons in the gap.An efficient low-pressure sealed-off cylindrical excilamp with capacitive discharge excitation is under discussion. Investigation was carried out on the characteristics of XeCl (lambda~308 nm), XeBr (lambda~282 nm), KrCl (lambda~222 nm) and XeI (lambda~253 nm) capacitive discharge excilamps. H- gh efficiency of exciplex molecules and simple design were obtained under capacitive HF discharge excitation. The lifetime of gas mixture in KrCl*, XeBr*, XeCl*, XeI* capacitive discharge excilamps over 3000 hours was demonstrated. Investigations of radiation of inert gases with haloids excited by high voltage pulses was carried out in the operating mixtures pressure range of 60-750 Torr at various inert gas/halogen. The highest pulsed power densities of KrCl, XeCl , XeBr , and KrBr molecules radiation were 3.7 kW/cm², 3.1 kW/cm², 4.5 kW/cm², and 2.1 kW/cm² at the efficiencies 5%, 4.8%, 5.5%, and 4%, respectively.