Guiding of highly charged ions through tilted capillaries promises to develop into a tool to efficiently collimate and focus low-energy ion beams to sub-micrometer spot size. One control parameter to optimize guiding is the residual electrical conductivity of the insulating material. Its strong, nearly exponential temperature dependence is the key to transmission control and can be used to suppress transmission instabilities arising from flux fluctuations of incident ions which otherwise would lead to Coulomb blocking of the capillary. We demonstrate the strong dependence of transmission of Ar 7+ ions through a single macroscopic glass capillary on temperature and ion flux. Results in the regime of dynamical equilibrium can be described by balance equations in the linear-response regime.

A relatively large yield of neutralized atoms was observed when 3 keV Ar 7+ ions were guided trough polyethylene terephthalate nanocapillaries. Time and deposited-charge dependence of the angular distribution of both the guided ions and the neutrals was measured simultaneously using a two-dimensional multichannel plate detector. The yield of neutrals increased significantly faster than that of guided ions and saturated typically at a few percent level. In accordance with earlier observations, both the yield and the mean emission angle of the guided ions exhibited strong oscillations. For the atoms, the equilibrium was achieved not only faster, but also without significant oscillations in yield and angular position. A phase analysis of these time dependencies provides insight into the dynamic features of the self-organizing mechanisms, which leads to ion guiding in insulating nanocapillaries.

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The time (i.e., integrated charge) dependence of electron transmission through a single glass macrocapillary was studied for incident 500-and 800-eV electrons at different capillary tilt angles. As the transmitted intensity goes to equilibrium, the centroid energies and corresponding energy values of the full width at half maximum of the transmitted electron distributions are found to vary in phase and out of phase with the transmitted intensity, respectively. Stable equilibrium was not fully reached even for large integrated charge due to sharp oscillations in the transmitted intensity. Plots of the recovery charging curves after breakdown show larger charge constants for the first recovery, but subsequently show smaller values that are about equal to one another for a given beam energy. Previously, such oscillations and recovery have not been reported for electrons.

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