Left: Probability of finding an injected nucleus or composition of nuclei fully disintegrated after propagating a specified distance (γ = 7 ⋅ 10⁹). The green and purple solid lines in the extremes correspond to ⁴He and ⁵⁶Fe injection, respectively, representing the lightest and heaviest initial compositions. The black solid line uses a similar composition as obtained in fits of the UHECR spectrum (Abdul Halim et al. 2024b). The specific nuclei and their approximate fractions are given in the legend. The dashed black line represents the case where all species share the same fraction and the dot-dashed black line a composition reflecting solar abundances. Right: Occupation probabilities for species in the nuclear cascade for ⁵⁶Fe injection (γ = 7 ⋅ 10⁹). The values are given for two propagation distances in the range where the full disintegration probability is negligible: 2 Mpc (purple) and 10 Mpc (green).