Charge-state distribution ofU238in nitrogen gas and carbon foil at 14 and15 MeV/nucleon

The charge-state distributions of U with energies of 14 and 15 MeV=nucleon were measured using nitrogen (N2) gas and carbon foil (C-foil) charge strippers. The most probable charge states of U with energies of 14 and 15 MeV=nucleon in N2 gas attain equilibrium at 60.8 and 62.4, whereas those in C-foils attain equilibrium at 75.8 and 76.7, respectively. Novel empirical formulas for the accurate prediction of the equilibrium charge states of U with energies 10–20 MeV=nucleon in gases and C-foil were derived by fitting the data in the energy range of 1–20 MeV=nucleon. The charge states predicted by using the formulas for gases and C-foil are in good agreement with the data in the energy range of 10–20 MeV=nucleon within an average of 0.23 and 0.21, respectively.