We extend an existing one dimensional simulation model for avalanche mode RPCs by the inclusion of diffusion and space charge effects. We investigate the influence of space charge on charge spectra, signal rise time, time resolution and charge-to-time correlation. We present a 1.5-dimensional model, which allows fast simulation of events and a two dimensional model that is slower but allows to study the transverse dispersion of avalanches due to space charge. [3,4]. They are constructed of two resistive electrode plates made of bakelite as shown schematically in Fig. 1a. Timing RPCs [5] with gas gaps of 0.2 to 0.3 mm are used in multi gap configurations [6] for Time-Of-Flight purposes [7]. They provide 99% efficiency and time resolutions down to 50 ps [8,9,10,11]. Different technologies with one or more resistive electrode plates are used. The two single gap designs investigated in this publication are shown in Fig. 1.
Preprint submitted to Elsevier Science