Understanding the detection mechanism of mm wave radiation in glow discharge detectors

Abstract

Sub-mm and mm waves are used in many applications such as spectroscopy and imaging, detection of weapons concealed under clothing, detection of diseases and non-destructive product inspection. By developing the THz detection mechanisms, the quality of this usability can be enhanced considerably. The commercial detectors currently used to detect THz waves range from Shottky diodes to bolometers, Golay cells and pyroelectric detectors. However, many of these detectors have limitations in terms of speed and responsivity. In addition, they have a common disadvantage of being expensive. For these reason, glow discharge detectors (GDDs) can be a good alternative since they are cheap and can detect mm-wave or THz radiations without the aforementioned limitations. To obtain optimal detection parameters, one needs to understand the interaction of the radiation with the plasma particles. In the literature, efforts to explain this interaction has focused on qualitative descriptions with analytical models. However, these theories have not been tested with real discharge parameters. For that reason, in this study, the plasma in the GDD is simulated by using previously developed parallel 1d3v Particle in Cell/ Monte Carlo Collision (PIC/ MCC) code to obtain the plasma parameters and determine the gas mixture ratios. Initial results show that the discharge current approximates the current measured through the home built glow discharge detector. Using these results an accurate simulation of the GDD discharge parameters has been performed. This platform will allow for understanding the effect of mm sub-mm radiation when added to the simulation which can aid in understanding optimum detection parameters.