Simulation of the response of the NA57 silicon pixel detector

A model to simulate the response of the Omega3 silicon pixel detector, used in the NA57 experiment, is presented. Geometrical charge sharing, electronic noise, threshold dispersion, capacitive coupling effects and $\delta$-ray production have been taken into account. The model has been tested on the Omega3 chip using Pb-Pb data collected in 1998. The model has also been implemented in the Alice off-line code and it will be used for the new ALICE chip, which is the direct descendant of the Omega3 chip. (7 refs).