Optical characteristics of a low-density electric discharge bromine vapor plasma in the UV-VUV spectral region

The emission characteristics of a glow discharge in bromine vapor have been investigated in the spectral region 130–350 nm. The current-voltage characteristics and the emission spectra of the glow discharge with an interelectrode gap of 10 cm and a discharge tube 14 mm in inner diameter have been studied. The emission characteristics have been optimized as functions of the bromine vapor pressure and the power deposited into the plasma. It has been shown that, at a low pressure of the bromine vapor, the emission spectrum of the lamp is determined by the spectral lines of atomic bromine in the range 158–164 nm, which are analogous to the known lines (such as those at 206.2 nm) of atomic iodine in an iodine-containing glow discharge plasma. As the pressure of the bromine vapor increases above 100 Pa, the intensity of these emission lines of the bromine atom decreases and the lamp spectrum is formed by bromine molecular bands in the form of a continuum with sharp boundaries (λ = 165–300 nm).