Penetration of 4.3 and 6.0 MeV/u highly charged, heavy ions through carbon foils

Experimental data on the charge-evolution functions F-q(D), including equilibrium fractions F-q(infinity) are presented when 4.3 MeV/u C2+ and 6.0 MeV/u Mg5+, Ca6+ and Kr13+ ions from the NIRS-HIMAC injector linac passed through carbon foils with the thickness over D = 10-350 mug/cm(2) range. The revised experimental F-q(infinity) values for 6.0 MeV/u C2+, Ne4+, Si5+, Ar8+, Fe9+ and Cu10+ ions previously reported are also given. The charge equilibrium thicknesses DE for bare and H-like ions are evaluated for projectiles lighter than Ca. The F-q(D), F-q(infinity) and D-E data are compared with the results calculated by the ETACHA code and the statistical model. It was found that the ETACHA code can reproduce quite well the observed F-q(D), F-q(infinity) and D-E data for projectiles lighter than Si (atomic number Z = 14) but the discrepancy becomes serious for heavier ions. The prediction of the statistical model for the equilibrium charge-state fractions F-q(infinity) agrees well with the observed experimental data for ions with Z > 18, i.e. heavier than argon. (C) 2004 Elsevier B.V. All rights reserved.