When a muon ( with energy around 1 GeV ) pass through a metal, such as Iron, which is about 1 mm in the z direction, how many energy the muon will lose ? Is there any formula to use?
Do a Google search for "muon energy loss in iron" and you'll get a number of links to PDF files by the Particle Data Group (pdg.lbl.gov). They contain equations and tables for charged particles passing through matter, and specifically for muons in iron.