Guided transmission of oxygen ions through Al2O3 nanocapillaries

The transmissions of oxygen ions through Al$_{2}$O$_{3}$ nanocapillaries each 50~nm in diameter and 10~$\mu $m in length at a series of different tilt angles are measured, where the ions with energies ranging from 10 to 60~keV and charge states from 1 up to 6 are involved. The angular distribution and the transmission yields of transported ions are investigated. Our results indicate both the existence of a guiding effect when ions pass through the capillary and a significant dependence of the ion transmission on the energy and the charge state of the ions. The guiding effects are observed to be enhanced at lower projectile energies and higher charge states. Meanwhile, the results also exhibit that the transmission yields increase as the tilt angle decreases at a given energy and charge state.