Guiding of 60keV O⁶⁺ Ions through Nanocapillaries in an Uncoated Al₂O₃ Membrane

We measure the transmission of O⁶⁺ ions with a higher energy of 60 keV (in turn a higher value of E_p/q) through capillaries in an uncoated Al₂O₃ membrane, and obtain agreements with previously reported results in general angular distribution of the transmitted ions and the transmission profile width variation with capillary tilt angle. The transmission fractions as a function of the tilt angle can be fitted to the semi-empirical Gaussian-like function well. Due to using uncoated capillary membrane, our ψ_c is larger than that using gold-coated one, in spite of our larger value of E_p/q, which suggests a larger equilibrium charge Q_∞ in our experiment.