Hello everybody, I investigate polycarbonate foils (makrofol) of 90 μm thickness irradiated by U-ions with a charge of z= +28 and a specific energy of 11.4MeV/nucleon. My problem is that in the Srim simulations the charge z is not questioned (or needed?), whereas the stopping power (-dE/dx) in the Bethe-formula is proportional to z^2. I compared the dE/dx values of SRIM (srim.org) with the Bethe-Calculator of Sven Geier (http://www.sgeier.net/tools/bbt.html) and my own Bethe-calculations, they all vary. My aim is the Bragg-curve, but therefore i would like to have the correct values/description of the stopping power. Im sorry for my bad english.