Charge state distribution of ^{86}Kr in hydrogen and helium gas charge strippers at 2.7 MeV/nucleon

The charge state distributions of krypton (^{86}Kr) with an energy of 2.7 MeV/nucleon were measured using hydrogen (H_{2}) and helium (He) gas charge strippers. A differential pumping system was constructed to confine H_{2} and He gases to a thickness sufficient for the charge state distributions to attain equilibrium. The mean charge states of ^{86}Kr in H_{2} and He gases attained equilibrium at 25.1 and 23.2, respectively, whereas the mean charge state in N_{2} gas at equilibrium was estimated to be less than 20. The charge distributions are successfully reproduced by the cross sections of ionization and electron capture processes optimized by a fitting procedure.