Characterization and design considerations of a radio frequency glow discharge spectral source for solid material analysis

This paper reports on the design and fabrication of a radio frequency (rf, 13.56 MHz) powered glow discharge source and its characterization for analytical atomic spectroscopy for solid sample analysis. The most attracting feature of rf coupling is its capability to sputter atomize conductive as well as non-conducive solid materials. The glow discharge lamp described here works under obstructed abnormal discharge condition in which the sample acts as a cathode. The fundamental processes occurring in rf powered glow discharges have been described for its characterization for direct solids elemental analysis. The discharge from the cathode surface, which is in contact with a water-cooled jacket, is observed side-on. The anode orifice diameter has been kept at 6 mm. In order to optimize the lamp performance the effect of discharge power, pressure, and dc self-bias potential, etc. on the emission intensity of copper spectral line (324.7 nm) have been studied.