Charge Exchange of Fast Iodine Ions in a Dense Jet of Carbon Dioxide

Charge distribution measurements were made with 10-75 MeV iodine ions of various incident charge states traversing either a supersonic CO2-jet of variable density in the range 5 x 1014 to 1.5 x 1017 molecules/cm3 or a target of dilute CO2 with a maximum density of 5 x 1014 molecules/cm3. The equilibrium mean charge ts of the iodine ions in the jet is found to be higher than in the dilute gas. The maximum difference of about one charge unit is observed at 75 MeV. Ihere is no indication for a further increase of Lat gas densities above 5 x 1016 molecules/cm3. Cross sections for electron capture and loss were determined by means of a least-squares-evaluation of non-equilibrium charge distributions. Considerable decrease of the capture cross sections for some lower charge states has proved to be responsible for the increase ¿, whereas the loss cross sections do not change measurably with increasing target density.