I’ve been wondering about energy loss of alphas and other heavy particles in thin surface coatings but am not sure how reliable the results are. For very thin (say, 10s of nanometers) layers, how can I be sure that the energy deposition values in the thin layer are realistic? Is the best approach to set the step size to ~1 nm in the volume and set a very low cut threshold? Is there a particular physics list best suited for this? Any thoughts would be greatly appreciated!