I am looking at muons being lost as they travel through a concrete bunker (with various things inside). The minimum energy (mean) for a muon to go through the walls is about 1.82GeV, and for the stuff inside (flakes of magnesium) it is 2.7GeV. For a piece of heavy metal it is 0.13GeV (it's only a small piece). The mean muon energy in the spectrum is ~6GeV. I want to know whether the attentuation due to the heavy metal is going to be noticeable or if it will be lost amongst the attenuation due to the concrete and magnesium (I have a feeling it won't but I need to prove it). Can you just add the energies and say that for a muon to pass through them all it must have above 4.65GeV? If so then if the heavy metal is not there (reducing the energy needed to 4.52) there probably isn't going to be a significant difference in flux. Is there a better way of going about this?