The Impact of Geometrical Quenching Factor in the Formation of Light Strips in EMA Configurations

For the particle detection when large area coverage is needed and wide surface must be instrumented, the gaseous detectors represent the only possible choice. Using GEM-type structures in the presence of proper quenching gas, it is possible to follow optically the charge particle tracks in gaseous position-sensitive detectors. Depending on the geometric parameters in these structures, this method can consider as an applied method for the detection of alpha particle tracks with specific accuracy. In this work, a Double EMA is presented as a new configuration of an Electron Multiplier Assembly (EMA), and the geometrical quenching factor concerning the electric field arrangement in the EMA through-holes is introduced as an effective parameter for the appearance of visible streamers in the space between EMA plates when they are employed as multiplication regions within a gaseous detector. In EMA arrays, in the presence of P10 gas at the threshold applied voltages, the light strips constantly emerge in the EMA through-holes exposed to radioactive source. In Double EMA, the formation of the regular electric field arrangement in the space of exterior EMA plates decreases the threshold applied voltage, thus enhancement the electron multiplication efficiency in the amplification region. With simulation of the electric field in the multiplication region, there is demonstrated the convergence of the electric field lines in the center of each hole as well as their divergence in the vicinity of the EMA electrodes can play the key role in the creating self-sustaining plasma regions in the EMA wall-less holes.