Design, modeling and simulation of a miniaturized gas ionization sensor: Optimization of the structure and operation

Abstract

Gas ionization sensor (GIS) work on measuring the breakdown voltage of gases that is unique for each gas. The gas breakdown inside the gas chamber occurs due to the ionization of gas molecules by accelerated electron impacts. The acceleration of electrons is very depending on the effective electric field applied on them. In this work we report the design, modeling, and simulation of a miniaturized GIS based on nanowires. In this report it is shown that the local electric field (responsible for the breakdown of gases) at the nanowire tip can be enhanced by optimizing the device structure and parameters such as nanowires shapes, the distance between the nanowires, and the nanowires lengths. We have developed simulating software based on an open source simulator XOOPIC. The simulation tool is based on combined Particle-In-Cell and Monte-Carlo-Collision approaches. The tool is developed to model and simulate the gas ionization sensor to detect various gases with optimized breakdown volatges. In order to enhance and speed up the design and simulations, the effective electric field, and screening effect due to the interaction between electric fields of individual nanowires were preliminary studies. For this we used COMSOL, a multiphysics simulation tool, and the results of these studies were used to model the device utilizing XOOPIC. In our model we have achieved designs for the devices with faster response and lower breakdown voltages for various gases.