This paper presents the results of study of the longitudinal low-pressure glow discharge in a helium/water mixture. This discharge is proposed for use as a mercury-free source of ultraviolet emission. The emission spectra in the ultraviolet range are recorded by a monochromator and analyzed. In order to interpret the experimental results, the numerical modeling is carried out using global model for 46 species and 577 plasma chemical reactions between them. This model allows us to define the main reactions responsible for the generation and quenching of the excited species, which emit in the ultraviolet range. The optimal conditions are found when the lines with wavelengths of 309 nm OH(A-X) and 150–190 nm OH(X-C,B) have the largest intensity.

This paper presents the results of a study of UV and VUV low-pressure lamp pumped by nanosecond capacitive discharge. This lamp works on the mixtures of helium and argon with water vapor (H 2 O) or 'heavy' water (D 2 O). At the capacitive low-pressure lamp emission spectra are mainly narrow band 308 nm OH (A-X) and large band in the VUV spectral range: 140-200 nm OH (C, B, A). Found, that the increasing the partial pressure of H 2 O and D 2 O (>130-150 Pa) led to a decrease in the intensity of VUV radiation of hydroxyl radicals. In the transition from He/H 2 O mixture to He/D 2 O mixture, the optimal pressure of helium is decreased. Reduced partial pressure of argon led to increased intensity of radiation of hydroxyl in the VUV range. The study of emission characteristics of OD*-lamps on a mixture of He/D 2 O and the OH*-lamps on a mixture of He/H 2 O showed that the intensity of the bands OD (X, C, A) is 1.5 times larger than the intensity of the bands OH (X, C, A). The maximum absolute intensity of UV-VUV radiation of the lamp (at a frequency of 1000 Hz) reached 1 W.