Energy Loss of Fast Oxygen Ions in Metal Foils : Emergence Angle and Change State Dependence

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The purpose of this research project is to investigate the dependence of energy loss of fast oxygen ions which transmitted thin metal foils on their emerging angles and charge states. We are also interested in the relation between charge state fraction adn emerging angle. We measured the angle-dependent energy loss of oxygen ions which have various change states by using Au foils in the term 1991 and 1992. The dependence of charge state fractions of oxygen ions on emerging angles was investigated with 1 to 50 mug/cm^2 carbon foils in the term 1992 and 1993.The charge states of emerging oxygen ions were vertically separated with magnetic field and detected by an position sensitive detector (PSD). Moving the PSD holizontally, we coud measure the angle-dependent energy loss of oxygen ions. As for the Au foil, the energy loss of oxygen ions was found to increase with increasing emerging angles. The amount of the increase was as large as that observed for protons in an Au foil. The charge state fraction was found to be almost independent of emerging angles. It was not confirmed that the energyloss of ions depended upon the charge state of emerging ions. These results were considered to be due to the thickness of the target foil.In order to investigate the dependence of the charge state fraction on emergence angles, we measured the angle-dependent charge fraction of oxygen ions for thin carbon foils. In the case of carbon foils for which the charge state nonequilibrium was observed, the charge fraction of emerging ions was found to depend strongly on emergence angles. Moreover, even for the thickness where charge state equilibrium was already attained we observed that charge fraction varied with increasing emerging angles. These measurements are expected to bring about the knowledge on the differential cross sections of charge changing reactions.