GEANT4 simulations of small cosmic ray detection modules based on scintillators and WLS bars

This paper describes the results of GEANT4 simulations for a prototype of detection module designed as a basic element of a low-cost, reconfigurable, modular mini-array for detection of cosmic rays. The basic layout of each individual module is based on a 400 cm2 scintillator tile, optically coupled to a Wavelength Shifter (WLS) bar and a Silicon Photomultiplier (SiPM) for light collection and readout. The array will include about 50 modules in its final stage, to be employed in various geometrical configurations. GEANT4 simulations of the transport of optical photons inside the detector are here reported, with the aim of estimating the key parameters contributing to the photon collection efficiency and compare different solutions.