Solar Orbiter/EPT particle data on 2021 October 30. The shock passing the spacecraft is denoted by the dashed black line and the background window used is denoted with a gray box. The top panel shows the original data without background particle intensity considerations (solid lines) and the fitted functions to the temporally evolving background in each energy channel (dashed lines), the middle panel shows a background subtracted data with the mean of the background window as a constant background in each energy channel, and the bottom panel shows a background subtracted data with a temporally evolving background from the fitted functions in the top panel.