SEPs intensities as a function of time. Panels (a) and (b): Energetic electron (panel a) and proton (panel b) measurements from the HET detector on board STEREO-A (STA; red markers) and STEREO-B (STB; blue markers) from the 0.7–1.4 MeV energy channel for electrons and 13.6–15.1 MeV for protons. Panel (c): Energetic iron measurements (30 min-averaged) from the LET detector on board STA and STB (respectively in dark red and dark blue) from the 2.7–10 MeV energy channel.