High power excilamps

Summary form only given. Study of radiation parameters and lifetime period of the manufactured barrier discharge excilamps has been performed. Average power of radiation for the just sealed off KrCl (λ ~ 222 nm) excilamp exceeded 100 W was obtained. The emitter with length of 1200 mm at external diameter 65 mm was tested. Length of a radiating surface has made 1100 mm. The tests were carried out with air cooling system. Maximal radiation power density was of 50 mW/cm², that corresponds to excilamp radiant power more than 100 W. UV output power of ~75 W and efficiency up to 10%, respectively, at λ ~ 308 nm (XeCl* excilamp) were obtained under excitation by pulses with frequency of 100 kHz. Application of water cooling allows increasing the radiant emittance of DBD coaxial excilamps. It was noted that in the coaxial quartz tube KrCl - excilamps excited by a barrier discharge, the maximum emission efficiencies are observed for a discharge in the form of diffuse cones. VUV output power of ~120 W at λ ~ 172 nm was obtained under excitation by pulses with frequency of ~100 kHz. The lifetime of gas mixtures in small XeCl and KrCl barrier discharge excilamps over 12000 and 8000 hours was demonstrated. There were analyzed the changes in the state of the quartz surface of KrCl-emitters after long life time. At the end of the test, the internal surface of the bulbs was covered with a matt coating comprised by the polymer products of chlorsyloxanes, which is an inevitable process in the excilamps containing molecular chlorine as the halogene carrier. The analysis of the optical characteristics of the modified quartz has shown the following. The transparency of the modified quartz in the UV-range spectrum has dropped. The transparency loss difference between the external and internal tubes indicates that the wall temperature influences significantly on the working mixture degradation. This complies with the assumption that the reaction of the - hlorsyloxanes formation is more active in the area with a higher temperature: the temperature of the internal wall of the heated excilamp ~ 150°C, while that of the external one is ~ 100°C. Therefore, it was drawn the conclusion that in order to operate the excilamp emitters subjected to higher energy contributions, it is necessary to use more intensive internal cooling, e.g. water cooling. 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 cones) takes place within one second as four stages with different discharge forms.