Left panel: the fraction of the initial energy of protons with energy E > 10¹⁸ eV converted to the energy of electrons from photomeson production at a distance r from the source. Right panel: the percentage of the initial energy of protons with energy E > 10¹⁹ eV converted to the energy of electrons from photomeson production (thick lines) and electrons from pair production (thin lines) at a distance r from the source.