Energy-dependent charge-changing cross sections and proton distribution of 28Si

The charge-changing cross sections (sigma(cc)) of Si-28 on a carbon target were measured with high precision at intermediate energies from 100 to 600 MeV/nucleon. The measured scc decreases rapidly from low energies up to 200 MeV/nucleon, whereas at higher energies it appears almost constant. The energy dependence of scc is compared with a Glauber-type model calculation where only the proton distribution of Si-28 is taken into account. A phenomenological correction factor deduced from the present data satisfactorily reproduces the experimental scc for other stable nuclei, whose charge distributions were determined by electron scattering and muon capture experiments.