Glow Discharge Spectrometry Group

Glow-discharge (GD) plasma formation is by the passage of electric current through an inert gas. Most probably, the earliest publication that mentions a GD proof of concept is from 1852 by W.R. Grove who includes it with the study of the electrical conductivity of gases. He introduces sputtering through discharge and thereby describes that the cathode erosion occurs by the electrical discharge. The GD lamp device was designed by Geissler (1857,) producing different colors with various gases later became instrumental to the stable, popular Hollow Cathode lamp, (type of GD) extensively used as an elemental line emission source for Atomic Absorption spectroscopy. Hittorf and Plücker did the early studies of atomic emission spectrometry (AES) using Geissler tubes in 1858, thereby pioneering GD-AES or GD-OES (Optical Emission Spectrometry). The Instrument birth of GD AES/OES for chemical analysis was the development of the Grimm type GD for flat metal samples, commercialized in 1968 as part of a complete spectrometer system. This was a direct current Plasma source, very field proven, stable, with spectra of linear calibration curves buildable. For the easy analysis of solid samples, the Grimm GD has had considerable accomplishment for several types of complex alloys, including multi-matrix materials application. A major improvement of the technique was the addition of Radio Frequency (RF) powered sources including pulsed mode for the Grimm Lamp (late 1980s) enable the analysis of non-conductive surface layers as well. Soon after the introduction of the Grimm lamp, Quantitative and Qualitative depth profiling (QDP) of layers, surfaces, interfaces, substrate, impurities determinations etc became prevalent. Considerably cost friendly GD spectrometers (price and cost of operation) enable it to the instrument of choice. The state-of-art of GD instrumentation and analysis methods will be discussed here