Nadeem Akram

Guiding of slow Ne7+-ions through insulating nano-capillaries of various geometrical cross-sections

We have studied guiding of slow highly charged ions through PET, SiO2, Al2O3, and now, for the first time, insulating nano-capillaries of non-circular cross-section. The guiding effect is been expl ...

Transmission of highly charged ions through nanocapillaries of noncircular cross sections

We report on effects from the geometrical shape of the guiding channels on the ion transmission profile. We find that capillaries of rhombic cross section produce rectangular shaped ion transmission profiles and, vice versa, capillaries of rectangular geometry give a rhombic beam shape. Our trajectory simulations for the incidence of 14-keV Ne7+ ions give clear evidence that the observed effect is due to the image forces experienced by the transmitting ions. They gain transverse energy due the image charge attraction towards the inner surfaces of the capillary. This leads to a defocusing of the ions leaving the capillaries. Due to the blocking of large deflection angles at the exit of the capillary, the transmitted ion beam is tailored into certain geometrical patterns.

Transmission of slow highly charged ions through rectangular nanocapillaries

Transmission of slow highly charged ions through rectangular nanocapillaries in phlogopite mica is studied. The transmission profiles have rhombic pattern at tilt angles within the geometrical opening angle of the capillaries. The time evolution of ion transmission reveals certain features contributing to the tailored transmission profiles.