782 ISSN 1054-660X, Laser Physics, 2007, Vol. 17, No. 6, pp. 782–797. © MAIK “Nauka / Interperiodica” (Russia), 2007. Original Text © Astro, Ltd., 2007. † 1. INTRODUCTION In many cases, the development and modernization of existing technologies involves the application of radiation sources. Lasers are the most widely used sources of induced radiation due to several unique fea- tures of laser radiation [1–5]. Nevertheless, spontane- ous sources exhibit advantages in several applications, primarily, due to lower price, simplicity, reliability, long lifetime, and a possibility for choosing spectral, energy, and time characteristics of the device. Sources based on a high-current pulsed discharge in gas are widely used as pulsed sources of spontaneous radiation. These sources are easy-to-use and provide a possibility for a variation in the main characteristics of radiation (spectral distribution, power, pulse duration, etc.). The results obtained for these sources are widely repre- sented in multiple publications in journals, mono- graphs, and reference books see, for example, [6–11]. The working principle of these devices is based on ohmic heating of gas in the presence of an electric cur- rent, which leads to a high-intensity emission of the gas-discharge plasma. Existing technologies and lamps predominantly allow emission in the visible spectral range, and their brightness temperature is about 10 kK [10]. Both cw and repetitively pulsed excitation of these lamps is normally characterized by an insignifi- cant specific energy input. This is the reason for a rela- tively long (10 9 –10 10 pulses) lifetime. † Deceased. The discharge plasma must be heated to no less than 20 kK to realize emission in the UV and VUV spectral ranges. In this case, the emitters are characterized by a hard UV component and are used in photosynthesis and photolysis of various compounds in gas and liquid phases; microelectronics; optical pumping of high- power gas lasers of the visible and UV ranges; UV ster- ilization of liquids, gases, and medical equipment; etc. The purpose is to develop reliable, technically simple, and relatively cheap lamps with high intensity and effi- ciency. Xenon is often used as the working gas due to relatively low near-electrode voltage drops and a high potential gradient [8]. Note that, in spite of the simplic- ity and feasibility of the ohmic heating of plasma, high- power UV sources that satisfy all of the practical requirements are not available. For example, some of the sources must exhibit selective and tunable radiation spectra and high spectral efficiencies in the UV and VUV spectral ranges. It is known that the plasma emission spectra of pulsed discharges contain both line and CW (back- ground) radiation. The line spectrum results from tran- sitions between discrete energy levels of neutral parti- cles and ions with various degrees of ionization. The cw radiation is related to the superposition of spectra formed due to elementary processes (line broadening owing to the interaction of particles, recombination, and free–free transitions) [6, 7, 12, etc.]. The intensity ratio of the lines and cw spectrum depends on the spe- cific power and energy of excitation, the pressure and composition of the working mixture, the configuration GAS LASERS Spectral Characteristics of a High-Current Pulsed Discharge in Xenon E. Kh. Baksht a, ***, A. M. Boichenko b, *, I. V. Galakhov c, **, V. I. Zolotovskii c, **, M. I. Lomaev a, ***, V. A. Osin c, **, D. V. Rybka a, ***, V. F. Tarasenko a, *** A. N. Tkachev b, *, and S. I. Yakovlenko † a High-Current Electronics Institute, Siberian Division, Russian Academy of Sciences, Tomsk, 634055 Russia b Prokhorov General Physics Institute, Russian Academy of Sciences, ul. Vavilova 38, Moscow, 119991 Russia c Russian Federal Nuclear Center, All-Russia Research Institute of Experimental Physics, Sarov, Russia *e-mail: kindep@kapella.gpi.ru **e-mail: osin@iskra5.vniief.ru ***e-mail: VFT@loi.hcei.tsc.ru Received November 16, 2006 Abstract—The radiation characteristics of a pulsed discharge xenon lamp are experimentally and theoretically studied. The data on radiation spectra are obtained for various compositions and pressures of working medium, energies and time profiles of excitation pulse, discharge gap configurations, etc. Electron temperature and mean spectroscopic symbol of emitting ions are estimated. It is demonstrated that cw radiation (continuum) results from the photorecombination transitions. PACS numbers: 52.80.Mg, 52.80.Yr DOI: 10.1134/S1054660X07060023