Custom Monte Carlo Model to Simulate the Spectroscopic Performance of CsPbBr ₃ Based Perovskite Detectors

Metal halide perovskites (MHPs), particularly CsPbBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>, have shown significant promise as materials for high-energy photon detection due to their favourable charge transport properties and high effective atomic number. However, the reported detector performance in the literature varies widely due to differences in device configurations and measurement conditions. In this work, we present a custom Monte Carlo simulation model designed to evaluate the spectroscopic response of CsPbBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>-based detectors with planar electrode geometry. The model has been adapted from a previously validated framework developed for CdTe and CdZnTe detectors and incorporates realistic physical parameters specific to CsPbBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>, including enhanced hole mobilitylifetime characteristics. Simulated energy spectra were generated for various radioactive isotopes, including Co57, Am241, and Cd109. The results show clear photopeaks corresponding to known gamma energies, and fluorescence features arising from Cs and Pb, consistent with experimental spectra. Comparison with published experimental data highlights strong agreement in spectral shape and energy resolution for the high-energy peaks, validating the model's capability to replicate real detector performance. This work demonstrates the potential of simulation-driven optimisation for next-generation perovskite-based gamma detectors and highlights the importance of hole-dominant signal modelling for accurate spectroscopic analysis.