Fabrication of Novel Ionization Hydrogen Sensors and Switching Glow-discharge Plasma-Based Gas Leak Probe using Carbon Nanostructures as Electron Emitter

In this thesis, a novel glow-discharge plasma-based sensor is introduced that works by fingerprinting the ionization breakdown characteristics of the unknown gases. It is well established that at a constant temperature and pressure, every gas displays a unique breakdown electric field. In addition the sensor exhibits a fast response and is not limited by considerations of reversibility and recovery. The system setup consists of a two-electrode system including graphite electrode (diameter: 6.5 mm), modified with arc-synthesized carbon nanostructures as anode and an aluminum disk with 2.4 mm diameter as cathode with inter-electrode distance of 700±10 µm inside a glass chamber. Fabricated sensor is able to specific detection of hydrogen (H2) at parts per billion (ppb) levels based on gas ionization process under vacuum condition (~0.01 torr). For H2 detection, ionization current is considered as detection system. A new H2 detection system is introduced based on the image processing of non-thermal glow-discharge plasma of the ionization of H2 at ppb levels based on gas ionization process under vacuum condition (~8 torr). The system setup also consists of a charge coupled device camera as detector. For this purpose, the blue component of the photographic image related to ionization-generated plasma is analyzed .The reason of distinct separation between breakdown voltages of different species, fabricated sensor is optimized for monitoring the leak of various gases such as O2, H2, Ar, He, CH3OH, CO and CO2 based on gas ionization process under vacuum condition (~0.01 torr). For gas leak monitoring, the ionization current is considered as detection system. In another activity, a novel gas phase titrimetry is introduced for acetylene determination at parts per million (ppm) levels based on the non-thermal glow-discharge plasma-based ionization of hydrogen standard gas solution. For this purpose, a constant flow of hydrogen gas solution is introduced to an ionization chamber containing a constant volume of acetylene gas solution. The endpoint (EP) of the titration is also indicated by the image processing of the plasma generated between a two-electrode system.