Pressure Dependence of Emission Intensity of Rare-gas Excimer Light Produced by Silent Discharge

Abstract

Spectroscopic research is performed for clarifying the pressure dependence of light emission from both excited xenon atoms and excimers produced by a silent discharge in the pressure range of 2 to 13kPa at the frequency of 60Hz between electrodes which consist of a pair of a needle and a glass-coated cylindrical-shaped metals. In the pressure range of 2 to 4kPa of xenon, two resonance lines of the wavelengths of 147 and 149nm, respectively, are observed separately. With the increase of the pressure, the intensity of those resonance lines become weak and the second continuum of the wavelength of about 172nm caused by excited dimers is eminently recognized. The first continuum does not increase with pressure compared with the second continuum. That may be caused by the loss processes such as collision relaxation. The same pressure dependence of the light intensity is also obtained for the case of krypton in the pressure range of 5 to 20kPa. At the pressure of about 10kPa of xenon, the intensity of first and second continuums becomes similar. As a result, about 30nm full width at half maximum of the emission is obtained. This shows that a wide range of vacuum-ultra-violet emission can be obtained even in one kind of gas by choosing an appropriate pressure.