Equilibrium Charge States of Br and I Ions in Solids and Gases in the Energy Range 10-180 MeV

Monoenergetic bromine and iodine ions from the Oak Ridge tandem accelerator and an MP tandem accelerator have been used to investigate the variations of ionic charge states with various gaseous and solid target materials. In these measurements, beams containing a single charge state and energy were obtained by magnetic analysis and passed through solid targets or windowless gas targets before passing through an electrostatic analyzer. The electrostatic analyzer was fitted with a position-sensitive silicon surface-barrier detector. The most probable charge states are compared with the general relationships given by Dmitriev and Nikolaev. Strongly non-Gaussian distributions have been found at certain energies; most of these irregularities have been associated with ionic shell effects and with multiple ionization.