Statistical coincidence model for threshold analysis in radiation position sensing based on scintillation-photon spectral variations

We present a statistical coincidence model for radiation position sensing based on scintillation-photon spectral variations. The model describes coincidence detection between short- and long-wavelength scintillation photons using analytical expressions, enabling much faster computation than Monte Carlo ray-tracing simulations. Comparison with experimental results supports the applicability of the model. Furthermore, theoretical and experimental results clarify the influence of coincidence thresholds on position sensing performance. The proposed model provides a practical tool for analyzing and optimizing coincidence threshold settings in radiation detectors based on scintillation-photon spectral variations.