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Stable transmission of a sub-μm-sized Ar8+ beam of 64–104-keV energy through glass tandem optics was achieved. The optics consisted of a 4-electrode tapered capillary and a sub-μm-sized tapered capillary tip, arranged in series. To actively discharge the capillary, and thus obtain stable transmission, an electrode was applied with a mechanical relay closing at a 0.01–0.1 Hz frequency. Transmitted beams were observed for tip outlets' diameters of 0.75 and 2.0 μm. When only a 4-electrode capillary was used, a beam density enhancement with a multiplicity of 14 times of the input beam density was achieved. A transmission efficiency up to 70% was observed with good reproducibility when the electrodes were biased with appropriate voltages.

A high-energy H+ microbeam generated by tapered glass capillary optics was applied to a single Escherichia coli cell, in order to evaluate the effects of irradiation on the activity of the flagellar motor and cell growth in real time. The flagellar motor of the tethered cells was stopped by irradiation with an average ion fluence of 2.0 × 1012 protons/cm2. When a lower dose was applied to the cells attached to the substrate, an elongated cell, which seemed ready to divide, divided into two daughter cells; however, the daughter cells did not elongate, neither did further cell division occur.

We present here a cell surgery scheme involving selective inactivation or disruption of cellular structures. Energetic ions are injected into a cell through a tapered glass capillary like a microinjection method. A slight but essential difference from microinjection is that a thin window is prepared at the outlet so that no liquid material can flow in or back through the outlet while still allowing energetic ions to penetrate into the cell. An ∼ MeV He ion beam from such a capillary having 10 μm outlet diameter inactivated a selected volume ( ∼ μm3) of fluorescent molecules located in a HeLa cell nucleus.

The authors have developed a method to produce a microbeam of slow highly charged ions based on a self-organized charge-up inside a tapered glass capillary. A transmission of 8keV Ar8+ beam through the capillary 5cm long with 800∕24μm inlet/outlet inner diameters was observed stably for more than 1200s. The transmitted beam had the same size as the outlet with a beam density enhancement of approximately 10 and a divergence of ±5mrad. The initial beam was guided through a capillary tilted by as large as ±100mrad, and it still kept the incident charge.