<p>This study presents a detailed Monte Carlo simulation of the prompt gamma activation analysis (PGAA) system, containing a sapphire filter (Al₂O₃). The flux distribution in the PGAA collimator was evaluated for different emission angles of the neutron source, indicating a strong angular variation. The neutron spectrum at the collimator exit was analyzed as a function of this angle to assess the effect of the sapphire filter and geometry. The isotopic production yield was calculated in the collimator area for several distances between the source and the collimator. The distribution of deposited heat was studied throughout the PGAA system, including successively the collimator with filter, the beam shutter, the neutron guide, the beam shaper, the irradiation chamber, the Teflon target, the HPGe detector and the beam stopper. The obtained results enable the optimization of the performance and the nuclear and radiological safety of the PGAA system for applications in nuclear analysis.</p>