Geant4 simulation of a scintillator-lead shashlik calorimeter with a SiPM readout

Shashlik calorimeters are sampling calorimeters which, in the last 20 years, have been used in many high-energy experiments: relatively cheap, they can be easily segmented and built in a large variety of geometries and they guarantee energy resolutions comparable to the ones achievable with homogeneous calorimeters. This article presents the complete optical simulation of a prototype of a scintillator lead shashlik calorimeter with silicon photomultipliers readout, characterized in terms of linearity, energy and spatial resolution. The simulation has been used to explain and validate the experimental data, obtained on the PS-T9 beamline at CERN, using electrons in the 1-7 GeV energy range.