A simulation tool for scintillating fibers coupled to SiPM for MIP and heavy ionizing particle identification

The MEG experiment searches for the μ+e+γ decay by stopping on a thin passive target the most intense continuous muon beam in the world. We are studying the possibility to have an active target, which should continuously monitor the muon beam and provide a precise measurement of the decay vertex, complementing the new spectrometer. The detector is based on thin scintillating fibers coupled to silicon photomultipliers (SiPMs), exploiting their insensitivity to the magnetic field, competitive PDE with respect to nominal PMT QE and low HV supply.This device can be used as a stand alone tool. In this paper we present a Monte Carlo simulation for a single fiber coupled to SiPM in order to study the propagation of the photons through the fiber and the response of the SiPM.