EQUILIBRIUM CHARGE-STATE DISTRIBUTIONS FOR IODINE IN GASES (1-12-MEV)

Equilibrium charge-state fractions Fi have been measured for iodine beams with energies between 1 and 12 MeV traversing gas targets of H2, He, O2, Ar, and Kr. Charge states from 0 to 14 were detected. At each energy, considerable differences in the charge-state distributions were observed in the different gases; both the mean charge ī and the distribution width σ showed strong dependence on the target gas. At energies above 3 MeV the value of ī was greatest in O2 and least in H2, and at all energies the value of σ was greatest in O2 and least in H2. At 12 MeV, values of ī and σ in O2 were 6.15 and 2.04, respectively, whereas in H2 the corresponding values were 4.02 and 1.12. © 1969 The American Physical Society.