Optical multiplexing for channel reduction in scintillator-based muon tomography system

Muon tomography leverages cosmic-ray muons for non-destructive imaging of dense and shielded objects. However, large-area scintillator-based detectors typically require a high number of readout channels, increasing system complexity and cost. This work presents an optical multiplexing scheme that significantly reduces the number of required channels without compromising spatial resolution. In the proposed approach, photons from multiple scintillator strips are collected via wavelength-shifting fibers and read out by a single Silicon Photomultiplier (SiPM), with an additional masking layer enabling unambiguous decoding. The multiplexing technique is validated through Geant4 simulations incorporating realistic cosmic-ray distributions and demonstrates that reconstructed images retain the resolution of systems with individual readouts. For a 1 × 1 m2 detector with four layers, the proposed method reduces the number of SiPMs and readout channels from 800 to 160, offering a scalable and cost-effective solution for large-area muon tomography.