Modeling of SQS propagation induced by alpha rays in gas counters

Referring to optical images of self-quenching streamer (SQS), we have already proposed a possible mechanism of SQS induced by α-rays. To check the validity of the mechanism, we have been designing a model for the computer simulation of SQS propagation. In the present modelling, in order to calculate the discharge growth, a set of continuity equations for electrons and ions is numerically solved in a two-dimensional space. Electron supply from the alpha-ray ionization track is assumed to be dominant process for the streamer development instead of the conventional electron-supply process which is based on the photoionization in the gas medium. The streamer propagation is simulated under the concept of a “two-region model”. A first comparison between computed and experimental results shows a good agreement