CHARGE-EXCHANGE OF LOW-ENERGY IONS IN THIN CARBON FOILS .2. RESULTS FOR IONS OF B, C, F, NE, NA, SI, S, CL, AR, K, AND FE

In order to calibrate a novel type of time-of-flight mass spectrometer to be flown in the solar wind, we have continued our investigation of the charge exchange of low energy ions passing thin carbon foils. We analyzed elements with widely different chemical properties: Ions of B, C, F, Ne, Na, Si, S, Cl, Ar, K, and Fe in the energy range 0.5-3 keV/u were passed through carbon foils with thicknesses between 1.1 and 10 mug/cm2, and their charge state distributions and residual energies were determined. It was found that (1) the charge state distribution behind the foil is independent of the charge of the incident projectile, (2) isotopes show the same charge exchange properties at equal velocities as we have found previously, (3) at the lowest energies the charge state distribution is no longer a function of the residual energy alone but depends on both residual energy and foil thickness, (4) probable differences in chemical properties between the front and back surfaces of the foil have no detectable influence on the charge exchange properties, and (5) strong electron shell effects manifest themselves when results for different elements are compared.