Front end electronics for high rate microstrip gaseous chamber readout

HERA-B is an experiment at the ep storage ring HERA at DESY designed to study the violation of CP symmetry in the B system. Groups from the Universities of Heidelberg, Siegen and Zurich develop the inner tracker system of the detector consisting of microstrip gaseous detectors and electronics for about 150 000 channels. For the readout system a completely new development in VLSI technology is necessary, because of the large number of channels and the high occupancy of up to 10% at beam crossing rates of 10 MHz. A simulation program has been developed including the basic detector response and possible filter strategies for optimisation of efficiency (>98%) and for minimisation of uncorrelated trigger signals. Chips, existing and in design phase, are analysed and compared with simulations and measurements. A concept for the complete readout system including first level trigger extraction and transmission of high data rates is presented.