Advanced mass spectroscopy techniques for trace analysis
Glow discharge is a kind of plasma that is an electrically neutral highly ionised gas comprising ions, electrons and neutral particles. It is normally derived from applying a potential difference between two electrodes inserted in a cell filled with a gas at specific pressure environment. Thereby, electrons emitted from the cathode are accelerated because of the potential difference and may collide with gas atoms and molecules, providing essentially excited particles. These particles decay to lower levels by emitting light and that is why this is called glow discharge. The various collision processes that take place in plasma result in a generation of several kinds of particles including electrons, atoms, molecules, radicals and ions. Being in constant interaction with each other, these particles constitute a highly complicated gas mixture, the glow discharge plasma. Challenged by this, a Belgian research centre extensively studied the theory of glow discharge plasma and made accurate numerical estimations of the radio frequency plasma gas temperature. This study provided the necessary background for exploring opportunities for developing different ion sources for glow discharge. Aimed at different purposes they developed different variants to glow discharge plasmas, including a direct current glow discharge for massive analysis of non-conducting samples. Moreover, a complementary radio frequency glow discharge ion source could be used for mass spectrometric analysis with many possibilities of improving the received signal. Furthermore, an enhanced planar radio frequency magnetron source could be used for optimisation of the analytical performance of trace analysis of glass and ceramics materials. Apart from the spectrochemical trace analysis of materials in analytical chemistry, the most important applications of glow discharges involve microelectronics and materials technology sciences. Additionally, they may be used in light industry (neon signs) in gas lasers and in flat plasma display panels (large area television screens). Most importantly, they may be used in environmental applications particularly those related with remote environment, such as in the creation of highly effective infrared light emitting diodes (IR-LED). The latter could be used for the remote control of self-explosive concentrations of volatile organic gases via fibre-optics line up to the distance of 2x1km.